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REESE  LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA 


ccession  No. 


THE    PURIFICATION 


OF 


PUBLIC    WATER 
SUPPLIES 


BY 

JOHN    W.    HILL 
1 1 

CONSULTING  ENGINEER 

MEMBER  AMERICAN  SOCIETY  OF  CIVIL  ENGINEERS,  MEMBER  AMERICAN  WATER  WORKS  ASSOCIATION, 
MEMBER  AMERICAN  PUBLIC  HEALTH  ASSOCIATION 


NEW  YORK 
D.  VAN  NOSTRAND  COMPANY 

LONDON 
E.  &  F.   N.   SPON,   125   STRAND 

i 


COPYRIGHT,  1898, 
BY  D.  VAN  NOSTRAND  COMPANY. 


TYPOGRAPHY    BY    C.  J.    PETERS    &    SON,   BOSTON. 


Plimpton  pres 

NORWOOD,   MASS. 


PREFACE. 


THIS  work  is  in  continuation  of  a  series  of  lectures  and  papers 
on  the  Quality  of  Public  Water  Supplies,  which  the  author  has 
had  the  honor  to  read  before  several  scientific  societies  and  uni- 
versities during  the  past  five  years,  and  is  intended  to  present  in 
a  brief  way,  (i),  the  fact  and  causes  of  pollution  of  sources  of 
public  water  supply;  (2),  the  effect  of  this  pollution  on  the 
typhoid  fever  rates  of  our  larger  cities ;  and  (3),  to  illustrate  by 
a  few  examples  how  the  typhoid  rates  have  been  reduced  by  the 
introduction  of  water  from  purer  natural  sources  and  by  filtration 
of  polluted  waters.  In  connection  with  the  subject  of  water 
quality,  brief  reference  is  made  to  the  water  bacteria,  and  some 
data  are  given  on  the  methods  of  construction  and  operation  of 
sand  filters,  together  with  the  cost  of  filter  construction  in  dif- 
ferent water-works,  and  the  cost  per  million  gallons  of  water 
treated. 

The  principal  object  in  bringing  out  this  work  at  the  present 
time  is  to  impress  upon  city  officials,  health  officers,  and  others 
connected  with  or  interested  in  works  of  public  water  supply,  the 
necessity  of  a  more  vigorous  attack  of  the  problems  of  "Water 
Pollution,"  and  "Purification  of  Water"  intended  for  drinking  and 
other  dietetic  uses. 

The  statistics  of  population  and  typhoid  fever  death  rates 
(Appendix  A)  have  been  obtained  from  health  officers,  water- 
works managers,  and  official  published  reports. 

The  author  has  endeavored  to  acknowledge  all  sources  of 
information  in  the  body  of  the  book  ;  but  especial  thanks  are  due 
Dr.  Dunbar  of  the  Hamburg  Hygienic  Institute  for  several  valu- 
able original  papers  on  water  supply  in  Germany ;  Mr.  Rud  Schro- 
der, inspector  of  the  Hamburg  water-works,  for  much  valuable 


iv  PREFACE. 

information  on  the  operation  of  these  filters ;  and  Mr.  Thomas 
W.  Boughen  of  Cincinnati,  who  by  the  author's  request  kindly 
undertook  to  collect  exact  information  upon  the  details  of  filter 
construction  and  operation  during  a  recent  tour  of  Europe. 

In  the  translation  of  German,  French,  and  Spanish  papers  and 
reports  on  European  water-works  and  the  hygiene  of  water,  he 
has  had  kind  and  valuable  assistance  from  Dr.  Philip  Hillkowitz, 
Charles  E.  Rasinsky,  and  Adolph  G.  Wulff,  graduates  of  the  Uni- 
versity of  Cincinnati.  Valuable  assistance  has  also  been  rendered 
by  Mr.  Paul  Hamilton,  a  graduate  of  the  University  of  Michigan, 
in  the  preparation  of  tabular  matter  on  recent  filter  practice,  etc. 

All  the  illustrations,  excepting  Figs.  10,  11,  and  12,  were  pre- 
pared especially  for  this  work  by  his  son,  Mr.  Henry  C.  Hill,  to 
whom  the  author  is  also  largely  indebted  for  patient  assistance, 
and  many  valuable  suggestions  in  connection  with  the  experimen- 
tal work  and  collation  of  authorities  for  matter  which  appears  in 
the  book. 

Chapter  I.  was  originally  read  as  a  lecture  before  the  Cincinnati 
Section  of  the  American  Chemical  Society  at  the  Cincinnati  Uni- 
versity, Jan.  15, 1897  ;  and  Chapter  II.  was  originally  read  as  a  lec- 
ture before  the  Academy  of  Medicine,  Cincinnati,  May  3,  1897. 
Chapter  IX.  was  originally  read  as  a  paper  on  the  "Sterilization  of 
Drinking- Water  as  a  Means  of  Reducing  the  Typhoid  Fever  Rates  " 

at  Buda-Pest,  September,  1894. 

j.  w.  H. 

CINCINNATI,  June,  1897. 


CONTENTS. 


CHAPTER   I.  PAGE 

INTRODUCTION 1 

Water  the  main  constituent  of  the  animal  system.  Difficulty  of  obtaining  exact  proof 
of  water  quality.  Modes  of  test  admissible  in  physics  not  applicable  to  test  of 
water  quality.  Changes  in  character  of  water  source  by  pollution.  General  confi- 
dence in  present  standards  of  water  quality  still  to  be  established.  Absolutely 
pure  water  not  found  in  nature,  nor  is  it  essential  for  dietetic  purposes.  In  the 
light  of  present  information  cities  are  not  justified  in  supplying  polluted  water 
to  consumers.  Hygienic  laboratory  at  Hamburg.  Management  of  filters  in  Hol- 
land. Sources  of  water  supply  to  the  cities  of  Manchester  and  Vienna.  Work  of 
Massachusetts  State  Board  of  Health  in  behalf  of  public  water  supplies.  The  fil- 
ters of  London  thirty  years  ago.  Zymotic  disease  and  prophylaxis.  Transmission 
of  pathogenic  organisms  through  the  medium  of  water  supply.  Failure  to  find 
the  typhoid  bacillus  in  polluted  water  not  to  be  taken  as  evidence  of  its  non-exist- 
ence. Pure  water  cannot  create  disorders  of  the  animal  system.  Pure  water  better 
than  purified  water.  Filtration  cannot  render  water  absolutely  pure.  Typhoid 
fever  rates  of  London,  Munich,  Berlin,  Chicago,  Pittsburg,  Louisville.  Habits 
of  people  in  the  United  States  and  Europe.  Interest  in  water  supplies  of  high 
hygienic  quality  by  the  large  cities  of  Europe. 

CHAPTER    II. 
SOURCES  OF  PUBLIC  WATER  SUPPLY 14 

Sources  of  water  supply  for  cities.  Hard  water  from  limestone  watersheds.  Other 
sources  of  water  pollution  than  sewage.  Professor  E.  Ray  Lankester's  opinion  on 
b.  typhosus  and  b.  colt  communis.  Rivers  and  lakes  receiving  surface  drainage 
cannot  be  regarded  as  uncontamihated  water  sources.  Sources  of  satisfactory 
water  supply  at  high  elevations  of  rare  occurrence.  Rivers  constitute  the  largest 
general  source  of  water  supply  for  cities.  Dilution  of  sewage-polluted  waters  can- 
not be  depended  upon  for  the  removal  of  disease  germs.  Longevity  of  typhoid 
bacillus  in  water.  Sewage  and  garbage  should  not  be  disposed  of  in  rivers  and 
lakes  which  constitute  sources  of  water  supply.  Dr.  G.  Sims  Woodhead  on  the 
avoidance  of  surface  drainage  into  the  Thames.  Professor  Baumeister  on  the  influ- 
ence of  dilution  of  sewage.  Lakes  subject  to  same  sources  of  water  pollution  as 
are  rivers.  Improvement  of  water  quality  by  sedimentation.  Experiments  by 
Dr.  Miquel.  Lake  Zurich  as  a  source  of  water  supply.  Self-purification  of  sewage- 
polluted  waters  cannot  be  seriously  entertained.  Dr.  Drown's  experiments  on 
aeration  of  polluted  waters.  Theory  of  self-purification  of  rivers  and  lakes.  Im- 
pounding reservoirs  not  safe  sources  unless  drainage  ground  is  laid  waste.  Pollu- 


VI  CONTENTS. 

PAGE 

tion  of  dug  wells.  Ground  water  may  be  well  purified  before  it  is  intercepted  by 
wells.  The  typhoid  fever  rates  as  an  index  of  water  quality.  Feasibility  of  prevent- 
ing direct  sewage  pollution  of  water  sources.  Filtration  to  be  successful  must  meet 
all  the  varying  conditions  of  the  unfiltered  water.  Failures  in  filtration  due  to 
ignorance  and  carelessness.  High  rates  of  filtration  not  admissible.  Deep  driven 
wells  not  always  proper  sources  of  water  supply.  Natural  filtration  through  mate- 
rials in  the  drift  not  always  complete.  Dr.  Rosenau's  investigation  of  deep  well 
water  supplied  to  San  Francisco.  B.  proteus  vulgaris  in  driven  well  water.  Dis- 
trust of  nearly  all  natural  sources  of  water  supply  by  foreign  investigators.  Chol- 
era a  disease  not  indigenous  to  this  country.  Typhoid  fever  the  principal  disease 
to  be  restrained  by  pure  water  or  water  purification.  Objection  to  water  otherwise 
pure,  but  high  in  mineral  constituents.  Sentiment  against  polluted  water  not  as 
strong  as  it  should  be.  Tests  of  water  quality.  Comparison  of  water  supplies  of 
Jersey  City  and  Newark,  N.  J.  Water  supply  of  Lowell  and  Lawrence,  Mass. 
Dr.  Rogers  on  causes  of  mountain  fever.  Mr.  Preller  on  pollution  of  mountain 
water  by  droppings  from  cattle.  Many  diseases  of  domestic  animals  are  also 
diseases  of  man.  Water  the  only  article  of  diet  of  universal  use.  Other  causes 
than  water  responsible  for  some  typhoid  epidemics,  but  polluted  water  is  regarded 
as  the  cause  of  high  continuous  typhoid  rates. 

CHAPTER   III. 
BACTERIAL  CONTENTS  OF  VARIOUS  WATERS 40 

Causes  of  variation  in  numbers  of  bacteria  from  same  source.  Bacteria  in  cistern 
water.  Bacteria  in  Ohio  River  water.  Longevity  of  pathogenic  bacteria  increased 
by  dilution  of  sewage.  Bacterial  contents  of  deep  well  water.  Determinations  by 
Professor  Sedgwick.  Bacterial  tests  of  deep  well  water  by  author.  Bacteria  in  water 
from  Pasteur  filters.  Freudenrich's  tests  of  Pasteur  filters.  Author's  tests  of 
water  from  Pasteur  filters.  Stone  disk  and  tube  filters.  Bacteria  in  water  from 
stone  disk  and  tube  filters.  Influence  of  days  of  growth  on  numbers  of  bacteria  in  a 
water  sample.  Spring  waters.  Bacterial  examinations  by  Dr.  Drown.  Bacterial 
examinations  of  spring  water  by  Professor  Sedgwick.  Tests  of  the  Ohio  River 
water  in  Parietti  solution.  Rainwater.  Bacterial  tests  by  Dr.  Miquel.  Bacterial 
tests  by  author.  Chemical  contents  of  rainwater  by  Dr.  Drown.  Bacterial  con- 
tents of  distilled  water.  Bacterial  contents  of  a  water  suspected  of  sewage  pol- 
lution. Bacterial  contents  of  water  from  small  Anderson  Iron  Purifier  and  sand 
filter.  Bacteria  in  artificial  ice.  Bacteria  in  the  air.  Influence  of  sunlight  on 
bacteria  in  water. 

CHAPTER   IV. 
THE  TYPHOID  BACILLUS  AND  TYPHOID  FEVER 56 

Properties  of  b.  typhosus.  Non-pathogenic  organisms  which  resemble  in  some  re- 
spects b.  typhosus.  Comparison  of  b.  typhosus.  b.  coll  communis,  and  b.  lactis 
aerogenes.  Experiments  on  b.  typhosus  and  b.  coli  communis  in  sterilized  milk. 
B.  coli  communis  and  b.  typhosus  in  polluted  water.  Dr.  Alessi's  experiments 
with  putrid  gases  on  rats,  guinea  pigs  and  rabbits.  Direct  proof  of  the  presence 
of  b.  typhosus  in  a  water  supply  not  essential.  Sanarelli's  papers  on  the  etiol- 
ogy of  typhoid  fever.  Typhotoxin.  Dr.  Jordan  on  the  identification  of  the 
typhoid  bacillus.  Mortality  from  typhoid  fever.  Seasonal  distribution  of  ty- 
phoid fever.  Reduction  of  typhoid  in  Munich.  Dr.  Reincke  on  typhoid  fever 
in  Hamburg  and  Altona.  The  large  cities  as  typhoid  fever  centers. 


CONTENTS.  Vll 

CHAPTER   V 

PAGE 

CLASSIFICATION  OF  CITIES  BY  TYPHOID  FEVER  STATISTICS     ...      70 

Final  test  of  water  supplies  is  the  influence  on  the  public  health.  Cities  of  the  first 
class.  Cities  of  the  second  class.  Cities  of  the  third  class.  Cities  of  the  fourth 
class.  Cities  of  the  fifth  class.  Cities  of  the  sixth  class.  Cities  of  the  sev- 
enth class.  No  city  of  the  United  States  in  the  first  class.  A  reduced  death  rate 
from  typhoid  fever  easy  of  attainment  if  desired  by  municipal  authorities.  Water 
supplies  of  Rotterdam,  Amsterdam,  and  The  Hague.  Water  supplies  of  Vienna, 
Munich,  Dresden,  Berlin,  London,  Edinburgh,  New  York,  Brooklyn,  Hamburg. 
On  the  use  of  beer  and  wine  by  people  of  Europe  and  the  United  States. 

CHAPTER   VI. 
PURE  AND  PURIFIED  WATERS 81 

Superiority  of  pure  and  purified  waters.  Sources  of  pure  water  very  rare.  Definition 
of  "pure"  and  ''purified"  waters.  Degree  of  water  "purity."  Protection  of 
watersheds.  Consumption  and  waste  of  water  in  American  cities.  Sources  of 
ground  water  supply.  Double  system  of  public  water  supply.  Advantage  of  water 
supply  from  sources  of  natural  purity.  Filtration  of  impounded  and  surface  waters 
for  public  supply.  Pollution  of  deep  well  water.  Objections  to  dual  water  sup- 
plies. Influence  of  sterilized  water  on  the  human  system.  Poisonous  mineral 
matters  in  ground  and  surface  waters.  Storage  of  ground  and  surface  waters.  In- 
fluence of  sunlight  on  the  growth  of  algae.  Comparison  of  water  supplies  of  small 
and  large  communities.  Sources  of  water  supply  of  Vienna,  Munich,  Dresden,  etc. 
Use  of  water  from  mechanical  filters  and  driven  wells.  Revenue  the  dominating 
factor  in  the  location  of  cities.  Feasibility  of  procuring  satisfactory  water  from 
natural  sources. 

CHAPTER    VII. 
CITATIONS  ON  TYPHOID  FEVER  EPIDEMICS 91 

Value  of  practical  illustrations  of  the  relation  of  water  quality  and  typhoid  fever. 
Epidemic  at  Lausen.  Epidemic  at  Caterham.  Epidemic  at  Plymouth,  Penn.  Epi- 
demic at  Zurich.  Epidemic  at  Spring  Water,  N.Y.  Epidemics  at  Lowell  and 
Lawrence,  Mass.  Epidemic  at  Sault  Ste.  Marie,  Mich.  Analysis  of  Sault  Ste. 
Marie  water.  Epidemic  at  St.  Louis,  Mo.  Epidemic  at  Elmira,  N.Y.  Relation 
of  San  Francisco  water  and  typhoid  fever.  Typhoid  rates  of  Denver,  Col.  Epi- 
demic at  Middletown,  Conn.  Epidemic  at  Stamford,  Conn.  Epidemic  at  Eliza- 
beth, N.J.  Typhoid  fever  at  Evansville,  Ind. 

CHAPTER   VIII. 
SEDIMENTATION  OF  POLLUTED  WATERS 110 

Experimental  information  rather  meager.  Miquel's  experiments  with  the  Seine 
water.  Limited  subsidence  can  produce  no  marked  change  in  quality.  Effective 
sedimentation  in  large  deep  reservoirs.  Reduction  of  bacteria  in  Ohio  River  water 
by  subsidence.  Reduction  of  bacteria  in  water  from  Lake  Linthrathen  by  subsi- 
dence. Reduction  of  bacteria  in  London  water  by  subsidence.  Experiments  with 
alum  and  slaked  lime  on  Ohio  River  water.  Effect  of  lime  process  on  Colne  Valley 
water.  Experiments  by  Professor  Lankester  with  mud  and  clay  in  Oxford  water. 
Experiments  by  Professor  Lankester  with  alum  and  lime  in  Oxford  water.  Experi- 


Vlll  CONTENTS. 

ments  by  Mr.  Flad  on  sedimentation  of  Ohio  River  water.  Rate  of  subsidence  of 
suspended  matter.  Experiments  by  Mr.  Dibdin  with  lime  in  the  New  River  water. 
Influence  of  lime  for  reduction  of  hardness  on  the  bacterial  contents  of  water.  Cost 
of  applying  the  lime  process  to  the  water  supply  of  London. 

CHAPTER   IX. 
STERILIZATION  OF  DRINKING-WATER .     120 

Purification  of  drinking-water  should  be  conducted  by  the  municipal  corporation  or 
water  company.  Use  of  boiled  water  in  cases  of  doubt.  Filtered  and  boiled 
water.  Investigation  of  the  method  and  cost  of  sterilizing  the  dietetic  water  for  a 
community.  The  Yaryan  process  of  water  sterilization.  Distribution  of  sterilized 
water  through  separate  system  of  small  mains.  Separate  services  for  sterilized  and 
unsterilized  water.  Construction  of  public  improvements  in  the  United  States 
influenced  by  political  considerations.  Use  of  sterilized  water  by  employees  at 
the  Columbian  Exposition.  Objections  which  have  been  raised  to  a  double  supply. 

CHAPTER  X. 
FILTRATION  OF  WATER  SUPPLIES 131 

Works  for  treatment  of  water  for  city  use.  Domestic  filters  not  a  safeguard  against 
contaminated  water.  Continuous  sand  filtration  in  Europe.  Filtration  cannot 
produce  absolutely  pure  water.  Theory  of  filtration.  Biologic  action  of  a  sand 
filter.  Scraping  and  aeration  of  sand-beds.  Action  of  bacteria  on  organic  matter 
in  water.  Penetration  of  sand-bed  by  bacteria.  Experiments  by  Piefke  with  sand 
filters  at  Berlin.  Head  on  Lake  Miiggel  filters.  Refilling  a  scraped  filter.  Inter- 
mittent sand  filters.  Theory  of  action.  Influence  of  the  nitrifying  bacteria  on 
organic  matter  in  water.  Lawrence,  Mass.,  intermittent  filter.  Natural  filtration 
in  the  materials  of  the  drift.  Comparison  of  pure  spring  water  with  purified  river 
water.  Artificial  filtration  more  reliable  than  natural  filtration.  Dr.  Drown's 
opinion  of  natural  filtration.  Sedimentation  and  filtration  in  Europe.  Time  al- 
lowed for  sedimentation  in  different  cities.  Mr.  Binnie  on  filtration  of  water  from 
Welsh  sources.  Filters  of  Altona,  Germany.  Mr.  Kiimmel  on  maximum  rate  of 
filtration.  Rate  of  filtration  at  the  Lawrence,  Mass.,  experiment  station.  Rate 
of  filtration  as  affecting  the  quality  of  Zurich  water.  Bacteria  in  London  waters. 
Operation  of  the  London  filters  (1896).  Bacteria  in  Hamburg  water.  Bacteria  in 
Lawrence  water.  Double  filtration.  Filtration  should  be  measured  by  practical 
results.  Influence  of  storage  on  waters.  Covered  and  open  reservoirs  for  filtered 
water. 

CHAPTER   XL 
TYPES  OF  SAND  FILTERS 158 

Classification  of  sand  filters.  Filters  with  vertical  walls  of  masonry.  Filters  with 
sloped  walls  of  earth.  Regulating  devices.  Advantage  of  sloped  walls  for  open 
filters  in  cold  climates.  Arrangement  of  drains  and  filtering  materials.  Capacity 
of  a  filter.  Scraping  the  surface  of  a  sand-bed.  Rate  of  delivery.  Grading  of 
filtering  materials.  Effective  size  of  sand  grain.  Uniformity  coefficient.  Sterili- 
zation of  filter  sand.  Lawrence,  Mass.,  intermittent  filter.  Rate  of  filtration. 
Periods  of  work  and  intermission.  Expense  of  operation  for  Lawrence  filter  for 
1895.  Rate  of  filtration  for  1895.  Bacterial  results  for  1895.  Cost  of  Lawrence 
filter.  Mr.  Shedd  on  sand  filtration.  Providence,  R.I.,  experiments  with  sand 
filters.  Bacterial  efficiency  of  plain  sand  filter  with  alum.  Lowell,  Mass.,  filter. 
Hudson,  N.Y.,  filters.  Poughkeepsie,  N.Y.,  filters.  Filter  galleries.  Filters  of 


CONTENTS.  ix 

Rotterdam.     Filters  of  The  Hague.     Filters  of  Amsterdam.    Bilters  of  Paris  sub- 
urbs.    Anderson  Iron  Process.     Filters  of  Zurich.     Extent  of  London  filters. 

CHAPTER   XII. 
MECHANICAL  FILTERS .    .  >.    .    184 

Operation.  Comparison  of  rates  with  London  plain  sand  niters.  Types  of  mechani- 
cal filters.  Experiments  at  Providence,  R.I.  Morison  mechanical  filter.  Worst  re- 
sults a  measure  of  efficiency  of  filtration.  Reduction  of  color  by  mechanical  filters. 
Results  with  and  without  alum.  Cost  of  filters.  Cost  of  operation  compared  with 
plain  sand  filters.  Use  of  mechanical  filters  in  American  cities.  Somerville  and 
Raritan,  N.J.,  filters.  Long  Branch,  N.J.,  filters.  Lorain.  Ohio,  filters.  Mechan- 
ical filtration,  Albany,  N.Y.  Mechanical  filtration,  Philadelphia,  Penn.  Elmira, 
N.Y.,  filters.  The  use  of  alum  for  filtration.  Influence  of  alum  on  the  human 
system.  Consumption  of  alum  in  filtration.  Drs.  Thomas  and  Marshall  on  alum 
filtration  for  Philadelphia.  Mechanical  filtration  works  in  cities  of  America. 
Reduction  of  iron  by  mechanical  filters,  Asbury  Park,  N.J.  Dr.  Dunbar  on  reduc- 
tion of  iron  in  German  ground  waters.  Reduction  of  iron  in  ground  water,  Read- 
ing, Mass. 

CHAPTER   XIII. 

HAMBURG  SETTLING-BASINS  AND  FILTERS 208 

History.  Settling-basins.  Conduit  from  settling-basins  to  filters.  Influent  cham- 
bers. Description  of  filters.  Collecting-drains.  Arrangement  of  filtering  materials. 
Washing  of  filtering  materials.  Quantity  of  filtering  materials.  Effluent  chambers 
and  regulating  weir.  Measuring  the  effluent.  Determining  the  size  of  filtration 
works.  Operation  of  the  filters.  Cleaning  a  filter.  Refilling  a  filter.  Clear- 
water  basin.  Period  of  operation  of  filters.  Sand-washing  machinery.  Schroder 
sand  washers.  Capacity  of  sand  washers.  Ice  on  filters.  Mode  of  cleaning  ice- 
covered  filters.  Mager  sand-scraper.  Comparison  of  old  and  new  methods  of  clean- 
ing ice-covered  filters.  Method  of  scraping  sand  during  winter  1896-1897.  Cause 
of  typhoid  epidemic,  autumn  of  1897. 

CHAPTER   XIV. 

THE  FILTERS  OF  THE  BERLIN  WATER-WORKS 230 

Works  at  Stralau  and  description  of  filters.  Works  at  Lake  Miiggel  and  description 
of  filters.  Regulation  of  filters.  Cost  of  covered  filters.  Clear-water  reservoir. 
Operation  of  filters.  Sand-washing  machine.  Bacterial  efficiency  of  filters. 

CHAPTER   XV. 
THE  FISCHER  FILTER  AND  ANDERSON  PURIFIER 238 

Fischer  filter  at  Worms,  Germany.  Cost  of  filter  compared  with  plain  sand  filters. 
Anderson  Revolving  Iron  Purifier.  Experimental  results  obtained  with  the  Ander- 
son Purifier  at  Paris.  Dr.  Dupre  on  Anderson  Purifier  at  Worcester,  Eng.  Cost 
of  purifying  water  by  the  Anderson  process.  Cost  of  installation  of  Anderson 
Purifiers. 

CHAPTER   XVI. 

FILTERS  PROPOSED  FOR  CINCINNATI .    246 

Condition  of  Ohio  River  water.  Experiments  on  Ohio  River  water.  Subsiding-reser- 
voirs.  Description  of  filters.  Arrangement  of  filtering  materials.  Regulating- 
chambers.  Clear  well.  Open  and  closed  filters.  Cost  of  original  and  amended 
plans  of  filters.  Cost  of  Berlin  and  Hamburg  filters. 


X  CONTENTS. 

CHAPTER   XVII. 

PAGE 

COST  OF  FILTERS  AND  FILTRATION 255 

Conditions  effecting  cost  of  works  of  filtration.  Estimated  cost  of  filters  for  Philadel- 
phia. Estimated  cost  of  filters  for  Providence.  Mr.  Hazen's  estimate  of  cost  of 
covered  filters.  Estimated  cost  of  filters  for  Cincinnati.  Open  filters.  Covered 
filters.  Estimated  cost  of  filters  for  Albany.  Capacity  of  clear  well.  Estimate  on 
a  system  of  ten  filters  and  clear  well.  Cost  of  Berlin  and  Hamburg  filters.  Cost 
of  Zurich  filters.  Cost  of  Lawrence  filter.  Rates  of  filtration  per  acre  per  day. 
Rates  proposed  as  standards  for  plain  sand  filters.  Duration  of  service  of  filters. 
Scraping  of  sand-bed.  Rotation  of  sand-bed.  Cost  of  scraping  the  London  filters. 
Washing  sand  for  filters.  Cost  of  filtration.  Estimate  of  cost  by  Mr.  Hazen. 
Estimate  of  cost  for  Philadelphia.  Estimate  of  cost  for  Albany.  Cost  of  filtra- 
tion at  Zurich.  Estimate  of  cost  for  Cincinnati.  Cost  of  filtration  at  London. 
Cost  of  filtration  at  Poughkeepsie,  N.Y.  Cost  of  operating  filters  in  Germany. 
Estimate  of  cost  of  filtered  water  per  capita  per  annum. 

APPENDIX   A. 
TYPHOID  FEVER  STATISTICS  FROM   LARGE  CITIES  OF  THE  WORLD,     268 

APPENDIX  B. 
THE  BACTERIA 272 

Chemical  composition.  Mycoprotein.  Products  of  bacterial  action  on  organic  mat- 
ter. Saprophytes  and  parasites.  Liquefiers  and  non-liquefiers.  Aerobians  and 
anaerobians.  Forms  of  bacteria.  Cocci.  Bacilli.  Spirilla.  Motility  of  certain 
species.  The  flagella.  Putrefactive  and  pathogenic  bacteria.  Chromogenic  spe- 
cies. Ptomains.  Toxins.  Measurement  of  the  bacteria.  Bacteria  in  air,  soil 
and  water.  Putrefactive  organisms  from  sewage  sources.  Spore-bearing  bacteria. 
Number  of  species  found  in  water.  Pathogenic  bacteria  found  in  water.  No 
proof  of  the  diphtheria  bacillus  being  transmitted  by  water.  Staining-properties 
and  differentiation.  Effect  of  high  temperatures  on  water  bacteria.  Bacteria 
resembling  in  some  respects  b.  typhosus  found  in  water.  Bacteria  smaller  than 
b.  typhosus  found  in  water.  Large  bacteria  found  in  water.  Spore-bearing  bacteria 
found  in  water. 

APPENDIX   C. 

THE  LEGAL  LIABILITY  OF  CITIES  AND  WATER  COMPANIES  FOR  DAM- 
AGES BY  SEWAGE  POLLUTED  WATER 287 


LIST   OF   ILLUSTRATIONS. 


FIG.  PAGE 

1.  TYPHOID   FEVER    RATES    NEWARK   AND  JERSEY   CITY,  N.J.     BLACK, 

NEWARK  ;  SHADED,  JERSEY  CITY 33 

2.  TYPHOID  FEVER  AND  RAIN-FALL  FROM  JANUARY,  1882,  TO  DECEMBER, 

1895.     (SAN  FRANCISCO,  CAL.) 105 

4.  I  YARYAN  APPARATUS  FOR  STERILIZING  WATER 127 

5.J 

6.  DIAGRAM  SHOWING  ACCUMULATION  OF  BACTERIA  IN  SAND-BED     .     .  135 

7.  DIAGRAM  SHOWING  OPERATION  OF  LONDON  FILTERS 151 

8.  DETAILS  OF  PROPOSED  FILTER  FOR  ST.  Louis  WATER- WORKS.    (KIRK- 

WOOD)     155 

9.  LONGITUDINAL  SECTION  OF  FILTER.     (LAWRENCE,  MASS.)  ....  167 

10.  EXPERIMENTAL  FILTER.     (PROVIDENCE,  R.I.) 170 

11.  JEWELL  GRAVITY  FILTER 185 

12.  MORISON  EXPERIMENTAL  FILTER.     (PROVIDENCE,  R.I.) 186 

13.  INFLUENT  CHAMBER  SHOWING  REGULATOR.     (HAMBURG,  GER.)     .     .  209 

14.  SECTION  OF  MAIN  DRAIN  AND  FILTERING  MATERIALS.     (HAMBURG, 

GER.) 211 

15.  PLAN  OF  FILTER.     (HAMBURG,  GER.) 212 

16.  EFFLUENT  CHAMBER  SHOWING  WEIR.     (HAMBURG,  .GER.)    ....  215 

17.  DIAGRAM  SHOWING  OPERATION  OF  FILTER  No.  12.    (HAMBURG,  GER.),  216 

18.  DIAGRAM  SHOWING  OPERATION  OF  FILTER  No.  16.    (HAMBURG,  GER.),  217 

19.  SAND- WASHING  PLANT,  HOPPER  No.  1.     (HAMBURG,  GER.)    .     .     .  221 

20.  SAND- WASHING  PLANT,  HOPPER  No.  2.     (HAMBURG,  GER.)         .     .  221 

oo'l 

03  f  SAND-WASHING  PLANT.     (HAMBURG,  GER.) 222 

24J 

25.  DIAGRAM  SHOWING  ICE  ON  FILTERS,  WINTER  OF  1896-1897.     (HAM- 

BURG, GER.) 224 

26.  DEVICE  FOR  SCRAPING  ICE-COVERED  FILTERS.     (HAMBURG,  GER.)   .  225 

27.  PLAN  OF  FILTERS  AT  LAKE  MUGGEL.     (BERLIN,  GER.) 231 

28.  PLAN  OF  REGULATING-CHAMBER.     (BERLIN,  GER.) 233 

29.  SAND-WASHING  MACHINE.     (BERLIN,  GER.) 236 

30.  FISCHER  FILTER.     (WORMS,  GER.) 239 

nnt  i  ANDERSON  REVOLVING  IRON  PURIFIER 242 

oOt>.  l 

31.  ^ 

32rt.  IPROPOSED  PLAN  FOR  OPEN  FILTERS.     (CINCINNATI,  O.)     .     .     .     .  248 
32^.  J 

xi 


THE  PURIFICATION  OF  WATER, 


CHAPTER    I. 

INTRODUCTION. 

WATER  is  an  essential  of  human  existence.  According  to 
Landois,*  58.5  per  cent  of  the  body  weight  is  water,  and  nearly  70 
per  cent  of  the  blood  corpuscles  is  water ;  of  the  serum  of  the 
blood,  90  per  cent  is  water,  f  No  other  article  of  "diet  enters  so 
completely  into  the  construction  and  support  of  the  animal  system. 
A  very  early  writer  held  that  the  blood  of  an  animal  was  life,  $  and 
the  use  of  it  as  an  article  of  food  was  interdicted  by  holy  law. 
Water  being  the  main  constituent  of  the  blood,  it  may  also  be 
regarded  as  the  principal  element  of  animal  life  ;  and  all  diligence 
should  be  exercised  in  procuring  for  dietetic  purposes  a  water 
which,  while  readily  assimilable  by  the  system,  shall  not  be  the 
cause  of  disease. 

It  is  a  curious  fact,  borne  out  by  the  many  costly  and  pains- 
taking investigations  into  the  resources  of  cities  for  public  water 
supply,  that,  after  all,  we  are  not  thoroughly  informed  upon  the 
question  of  water  quality.  This  is  not  in  disparagement  of  the 
labors  of  the  many  able  investigators  along  this  line  of  scientific 
research  ;  but  while  in  nearly  every  other  branch  of  physics  satis- 
factory proof  of  certain  qualities  of  matter  can  be  had,  the  absolute 
proof  of  the  hygienic  quality  of  water  supplies  is  still  beyond  the 
reach  of  our  most  modern  methods  of  research.  If  one  is  disposed 
to  question  this  statement,  his  careful  attention  is  invited  to  the 

*  Landois'  Human  Physiology. 

t  Transactions  American  Society  of  Civil  Engineer 'S,  vol.  xxxii.,  p.  151. 

J  Genesis,  chap,  ix.,  v.  4. 

1 


2  THE  PURIFICATION  OF   WATER. 

views  of  some  of  the  ablest  water  analysts  of  England,  as  shown 
by  the  exhaustive  investigation  of  the  Royal  Commission  on 
Metropolitan  Water  Supply.* 

If  one  is  in  doubt  as  to  the  strength  of  a  bar  of  steel,  he  can 
easily  resolve  his  doubts  by  putting  a  specimen  into  a  testing- 
machine  and  breaking  it.  The  results  will  satisfy  him  upon  all 
the  physical  properties  of  the  metal.  If  he  desires  to  pursue  the 
inquiry  further,  he  can  obtain  very  satisfactory  evidence  of  the 
composition  of 'this  steel,  and  reasoning  a  priori,  can  make  as 
many  bars  substantially  like  his  specimen  as  may  be  desired. 

Examinations  of  water  samples,  however,  are  not  so  satisfac- 
torily conducted.  The  results  obtained  at  one  time  are  not  often 
verified  by  subsequent  tests.  Changes  in  the  chemical  and  bio- 
logical condition  of  the  water  are  constantly  going  on  ;  and  it  is 
not  unlikely  that  a  public  water  supply  might  comply  with  all  the 
recognized  standards  of  potability  at  one  time,  and  be  subject  to 
just  condemnation  at  another.  And  right  here  lies  the  danger 
to  communities  which  depend  upon  water  from  a  common  source. 

The  experience  at  Plymouth,  Penn.  (1885),  shows  how  a  hith- 
erto satisfactory  source  of  water  supply  may  become  an  agent  of 
destruction,  with  no  preliminary  indications  of  the  time  or  nature 
of  the  changes  which  were  taking  place  in  the  previously  pure 
water  of  this  little  mountain  reservoir. 

The  terms  "  pure  "  and  "  impure  "  with  reference  to  water  are 
used  advisedly.  If  the  water  is  safe  for  drinking  and  dietetic  pur- 
poses, it  is  "pure"  although  such  water,  if  from  natural  sources, 
would  not  be  found  chemically  and  bacterially  "  pure  ; "  while  an 
"impure"  water  is  one  that  is  the  cause  of  disease,  even  though 
the  chemist  and  bacteriologist  might  not  be  able  to  decide  upon 
the  evidence  or  nature  of  the  impurity.  Impurities  may  come 
into  water  from  the  atmosphere,  from  surface  drainage,  and  from 
sewage.  But  the  impurities  which  are  feared  in  water  are  the 
pathogenic  and  putrefactive  bacteria,  and  the  ptomains. 

The  pathogenic  bacteria  are  those  specifically  concerned  in 
disease,  and  held  to  be  a  part  of  its  etiology.  The  putrefactive 
bacteria  found  in  all  water  rich  in  organic  matter,  especially  from 

*  London,  Eyre  &  Spottiswoode,  1893. 


JNTR  OD  UC  TION.  3 

sewage  sources,  may  produce  disorders  of  the  •  digestive  tract, 
although  not  held  to  be  the  specific  agents  of  disease.  The 
ptomains  have  never  within  the  author's  knowledge  been  found  in 
water,  although  it  is  reasonable  to  suppose  that  such  may  come 
into  water  from  putrefying  organic  matter  lying  upon  the  fore- 
shores of  rivers  and  lakes ;  but  the  dilution  of  these  will  be  very 
great  in  all  ordinary  instances  of  rivers  and  lakes  constituting 
sources  of  water  supply. 

The  biologist  and  bacteriologist  deal  in  matter  found  only  in 
suspension  in  water ;  and  dangerous  substances  may  exist  in  solu- 
tion, and  their  methods  of  search  would  not  disclose  the  fact.  If 
ptomains  ever  occur  in  a  water  supply  they  will  be  in  solution,  and 
the  ordinary  chemical  water  analysis  will  not  reveal  them.  Indeed, 
the  proof  by  chemical  means  of  a  ptomain  or  toxic  substance  in 
water  will  be  found  upon  investigation  to  be  very  difficult,  if  not 
altogether  impossible,  by  any  known  process.*  It  is  a  disputed 
question  whether  Brieger  and  his  co-laborers  have  really  precipi- 
tated the  toxic  substances  of  bouillon  cultures  of  the  pathogenic 
bacteria,f  and  altogether  it  may  be  held  that  the  absolute  proof  of 
water  quality  is  still  an  unattainable  result. 

This  fact,  however,  should  not  diminish  the  perseverance  of 
the  workers  in  the  field  of  water  analysis  and  purification,  but 
rather  serve  as  a  stimulus  to  stronger  and  higher  efforts  in  behalf 
of  the  thousands  who  annually  perish  from  water-borne  diseases. 

That  certain  waters,  when  judged  by  our  present  standards,  are 
held  to  be  safe  for  drinking  and  other  dietetic  purposes,  while 
other  waters,  judged  by  the  same  standards,  are  held  to  be  unfitted 
for  such  uses,  we  all  know  ;  but  general  confidence  in  these  same 
standards  is  still  to  be  established. 

Absolutely  pure  water  is  not  found  in  nature.  All  water,  from 
whatever  source,  even  freshly  fallen  rain-water,  contains  some  evi- 
dences of  contamination  ;  but  according  to  our  standards,  water 
fit  to  drink  is  often  found  in  natural  sources.  It  is  not  essential 
that  water  for  drinking  and  dietetic  purposes  be  chemically  and 

*  Royal  Commission  on  Metropolitan  Water  Supply,  London,  1893.  Professor  E.  Ray 
Lankester,  Appendices  to  Evidence,  p.  452. 

t  Annales  de  rinstitut  Pasteur,  Sanarelli,  April,  1894. 


4  THE  PURIFICATION  OF   WATER. 

bacterially  pure ;  but  it  is  essential  that  it  contains  no  pathogenic 
organisms,  and  shall  be  free  from  ptomains  due  to  the  action  of 
bacteria  upon  decaying  organic  matter.  Whether  the  latter  have 
really  occurred  in  drinking-water  is  not  certainly  known,  but  some 
investigators  at  the  present  time  seem  to  suspect  the  possibility 
of  it. 

The  pumping  of  water  for  domestic  uses  from  a  source  known 
to  be  polluted  by  sewage  or  otherwise  should  be  severely  con- 
demned. The  delivery  of  water  containing  the  elements  of  fatal 
disease  to  a  confiding  and  helpless  community  should  be  ranked 
with  the  sale  of  intoxicating  liquors  to  minors  and  confirmed  in- 
ebriates. An  attempt  to  kill  people  by  the  systematic  distribution 
of  a  poison  would  be  met  by  the  apprehension  and  punishment  of 
the  offender ;  while  the  delivery  of  water  for  drinking  and  other 
dietetic  uses,  as  fatal  to  some  as  a  dose  of  strychnine,  is  going  on 
in  nearly  every  large  city  of  the  land.  Shall  we  shut  our  eyes  to 
the  fact  that  polluted  water  is  dangerous  to  health,  or  shall  we 
recognize  the  evil,  and  address  ourselves  to  its  remedy  ? 

Every  city  which  continues  to  supply  a  tainted  water  without 
earnest  and  intelligent  efforts  at  abatement,  is  guilty  of  a  barbar- 
ism not  tolerable  in  this  age  of  enlightenment  and  progress.  The 
interest  taken  in  the  quality  of  public  water  supplies  during  the 
past  ten  years  is  well  shown  by  the  work  of  the  Royal  Commission 
on  Metropolitan  Water  Supply,  London  (1893)  ;  by  the  magnifi- 
cent and  far-reaching  work  of  the  Massachusetts  State  Board  of 
Health,  1890,  et  seq.,  and  of  several  important  commissions  upon 
city  water  supply  in  this  country  and  abroad  ;  and,  finally,  by  the 
independent  labors  of  many  able  and  patient  investigators,  like 
Professor  Frankland,  Dr.  Miquel,  Dr.  Prudden,  and  others. 

The  Royal  Commission  on  Water  Supply  to  London  covered 
more  ground,  and  was  more  searching  in  its  investigations,  than 
any  similar  body  that  has  hitherto  acted  on  behalf  of  a  municipal 
corporation  ;  and  without  regard  to  its  conclusions,  which  may  be 
open  to  discussion,  there  can  be  no  doubt  of  the  great  ability  of 
the  commission  and  of  the  men  called  to  give  evidence  before  it. 

The  whole  field  of  inquiry,  from  the  available  capacity  of  the 
London  watershed  to  the  quality  of  the  water  which  may  be  had 


INTR  OD  UC  TION.  5 

from  the  most  perfect  works  for  filtration,  was  fully  covered.  The 
ablest  men  of  England,  in  geology,  medicine,  chemistry,  biology, 
bacteriology,  and  sanitary  and  hydraulic  engineering,  were  called 
before  the  commission,  and  evidence  was  taken  upon  every  point 
which  by  any  means  could  affect  the  quantity  or  quality  of  the 
water  required  by  the  metropolis  ;  and  minute  inquiry  was  made 
into  the  possibility  of  transmitting  certain  zymotic  infectious  dis- 
eases by  drinking-water. 

The  Hygienic  Laboratory  of  Hamburg,  so  far  as  it  relates  to  a 
supervision  of  the  quality  of  water  supplied  to  the  citizens,  is 
perhaps  more  complete  than  that  of  any  other  city  in  the  world. 
Dr.  Dunbar,  a  former  resident  of  St.  Paul,  Minn.,  and  now  a  citi- 
zen of  Germany,  is  in  charge  of  the  laboratory ;  and  every  facility 
is  afforded  him  for  complete  surveillance  and  control  of  the  quality 
of  the  city  water  supply. 

The  management  of  the  niters,  and  maintenance  of  the  quality 
of  the  water  supplied  to  the  chief  cities  of  Holland,  are  as  care- 
fully conducted  in  the  interest  of  the  public  health  as  are  the 
boilers  and  pumping-engines  operated  in  the  interest  of  the  public 
purse.  By  the  combined  efforts  of  the  engineers,  chemists,  and 
bacteriologists  connected  with  the  water-works  of  Holland,  the 
water  is  pumped  with  the  greatest  ecomony  of  fuel,  and  is  con- 
sumed by  the  people  with  the  least  loss  of  life  from  water-carried 
diseases. 

The  city  of  Manchester,  Eng.,  realizing  the  value  to  its  pros- 
perity of  an  unimpeachable  public  water  supply,  has  recently 
bought  a  lake  (Thirlmere)  in  County  Cumberland,  and  much  of 
the  proximate  drainage  ground,  and  conducts  this  water  to  the 
city  through  conduits  aggregating  in  length  one  hundred  and  two 
miles.  Vienna,  from  a  city  having  at  times  typhoid  fever  rates 
as  high  as  any  in  Europe,  by  abandoning  its  former  sources  (the 
Danube  and  wells),  and  seeking  its  water  in  the  Austrian  Alps, 
has  become  one  of  the  least  typhoid  fever  infected  centers  in  the 
world. 

The  extensive  labors  of  the  Massachusetts  State  Board  of 
Health  at  its  Lawrence  experiment  station  have  been  guided  by 
two  chief  objects,  —  one  the  treatment  of  urban  sewage  by  practical 


6  THE   PURIFICATION  OF   WATER. 

methods,  which  will  render  the  effluents  innocuous  to  health,  and 
the  other  the  development  of  information  upon  practical  methods 
of  sand  filtration  of  polluted  waters. 

Independent  investigators  have  been  seeking  information  upon 
the  exact  chemical  and  biological  character  of  various  waters  all 
over  the  world.  Research  has  been  conducted  along  the  line  of 
water  transmission  of  disease  ;  and  the  organisms  concerned  in 
the  etiology  of  infectious  disease  have  been  patiently  and  carefully 
studied. 

The  practical  work  of  cities,  and  the  scientific  work  of  the 
analysts,  clearly  point  to  great  changes  along  the  line  of  public 
water  supply.  Thirty  years  ago  the  sand  filters,  which  we  now 
find  in  the  London  water-works,  were  filtering  water  from  the 
rivers  Thames  and  Lea,  as  they  are  now ;  but  no  one  at  that  time 
suspected  what  these  filters  really  were  doing.  The  water  com- 
panies and  consumers  believed  that  the  filters  were  making  a 
great  improvement  in  the  quality  of  the  polluted  river  waters,  but 
the  physics  of  sand  filtration  were  at  that  time  not  written  and 
not  known. 

Naturally  enough,  processes  conducted  in  ignorance  of  the 
rationale  of  every  step  and  each  reaction  seldom  attain  the  high 
efficiency  which  follows  manipulation  along  lines  based  upon  a 
clear  knowledge  of  all  the  causes  operating  to  produce  a  common 
result.  And  if  the  filters  of  the  London  water-works,  as  ope- 
rated thirty  years  ago,  failed  to  furnish  water  of  a  quality  equal  to 
that  now  obtained,  the  fault  was  not  in  the  principle  of  the  filter, 
but  in  the  lack  of  experimental  information  upon  the  part  of  the 
eminent  engineers,  who,  like  Mr.  James  Simpson,  designed  and 
operated  them.  This  knowledge  has  since  been  supplied  by  the 
Pasteurs,  the  Kochs,  the  Franklands,  and  the  Mills,  who  have  each 
in  his  way  furnished  some  of  the  material  by  means  of  which 
the  practice  of  water  purification  has  reached  a  firm  foundation. 

When  Mr.  James  P.  Kirkwood  went  abroad  in  the  spring  of 
1866,  to  examine  the  works  of  water  purification  at  that  time  in 
use  in  several  European  cities,  notably  London,  the  subject  of 
water  quality  rested  entirely  upon  the  chemical  tests  for  organic 
matter.  The  filter  was  regarded  as  a  fine  strainer,  or  as  Mr.  Kirk- 


INTRODUCTION.  1 

wood  says,*  "They  (the  sand  filters)  become  indeed  screens  of 
the  greatest  delicacy,  intercepting  all  material  impurities,  not  the 
least  of  which  are  the  very  small  fish  with  which  all  waters  are 
crowded  at  certain  seasons." 

Something  smaller  than  fish  were  then  held  back  by  the 
London  filters  ;  this  much  was  known,  but  no  mention  had  then 
been  made  of  the  action  of  bacteria  in  water  on  organic  matter, 
of  the  "  Schmutzdecke,"  which  in  Germany  is  regarded  at  once 
as  the  evidence  and  cause  of  successful  sand  filtration,  or  of  the 
action  of  the  nitrifying  organisms  in  converting  compounds  of 
ammonia  into  nitrous  and  nitric  acids. 

These  things  were  being  done  by  the  London  sand  filters  in 
1866,  not  so  perfectly,  perhaps,  but  in  a  measure  as  they  are  now ; 
yet  the  bacteria  were  in  the  London  water  then  as  at  present,  but 
no  one  was  conducting  gelatin  plate  cultivations,  and  searching  in 
drops  of  water  for  little  organisms,  so  small  in  any  dimension  as 
to  be  beneath  notice,  f 

Organic  matter  in  suspension  in  the  water  was  being  split  up 
into  carbon  dioxide  and  other  gases  and  into  nitrogenous  com- 
pounds by  bacterial  action ;  but  no  one,  not  even  Dr.  Letheby, 
mentioned  it  to  Mr.  Kirkwood  upon  the  occasion  of  his  visit 
to  London.  The  gelatinous  Schmutzdecke,  which  Herr  Piefke  J 
writes  upon  so  ably,  and  argues  as  the  very  essence  of  successful 
sand  filtration,  was  being  formed  on  the  sand-beds  ;  but  the  British 
workman,  who  shoveled  off  the  upper  one-half  or  three-quarters  of 
an  inch  of  sand  from  a  clogged  filter  bed,  never  noticed  it.  The 
partial  or  complete  aeration  of  a  filter  when  it  was  temporarily 
out  of  service  was  never  suspected  as  a  means  of  maintaining 
the  nitrifying  organisms  in  the  sand-bed.  In  short,  the  real  ac- 
tion of  a  sand  filter  was  then  unsuspected,  the  bed  of  sand  being 
considered  somewhat  superior  to  a  molder's  sieve  for  the  intercep- 
tion of  suspended  matter  in  the  water. 

The  celebrated  Dr.  Letheby  §  freely  admitted  "  that  we  have 


*  Filtration  of  River  Waters,  by  James  P.  Kirkwood,  New  York,  1869,  p.  7. 
f  This  term  is  not  here  used  in  the  same  sense  as  under  observation. 
\  Die  Principien  der  Reinwassergewinnung  vermittelst  Filtration,  Berlin,  1887- 
§  Filtration  of  River  Waters,  by  James  P.  Kirkwood,  New  York,  1869,  p.  26.    . 


8  THE   PURIFICATION  OF    WATER. 

not  at  the  present  time  any  absolute  test  for  discovering  organic 
matters  in  water,  much  less  the  nature  of  these  organic  matters;" 
but  great  as  has  been  the  progress  in  the  chemistry,  biology, 
and  bacteriology  of  water  since  Dr.  Letheby  penned  these  lines, 
much  remains  to  be  done  in  applying  the  knowledge  gained  in  a 
practical  way. 

If  it  be  true  that  by  proper  prophylaxis  certain  zymotic  diseases 
may  be  made  to  disappear,  why  are  we  so  slow  in  adopting  the 
remedies  which  science  and  history  have  pointed  out  ?  Are  we 
in  doubt  of  the  correctness  of  our  conclusions,  or  are  we  indiffer- 
ent to  the  sacrifice  of  human  life  ? 

It  is  not  the  author's  purpose  at  this  time  to  discuss  any  special 
methods  of  purification  for  polluted  waters.  This  will  be  done 
under  their  respective  headings  ;  but  the  fact  has  been  demon- 
strated so  often,  especially  abroad,  that  methods  upon  a  large  scale 
can  be  so  conducted  as  to  command  the  quality  of  a  water  supply, 
and  one  who  opposes  the  purification  of  water  supplies  upon  the 
ground  of  impracticability  must  be  set  down  as  not  being  well 
informed  on  water  purification  or  as  an  enemy  of  the  public  health. 

Professor  Percy  Frankland,*  after  comparing  the  operation  of 
the  London  filters  for  a  series  of  years  with  certain  deductions 
which  he  had  drawn  from  an  earlier  investigation  of  these  filters, 
stated  :  — ' 

"  The  importance  of  these  results  lies  in  their  proving  that  in  the  matter 
of  sand  filtration  we  are  no  longer  working  in  the  dark,  but  that  we  now  know 
the  factors  upon  which  the  success  of  the  process  depends,  and  by  attention  to 
which  its  efficiency  may  be  maintained  or  even  increased." 

The  tracing  of  disease  through  a  sewage-polluted  water  may 
be  obscure  to  some;  but  if  a  certain  source  of  water  supply  is 
known  to  be  polluted  at  some  point  with  the  organisms  concerned 
in  disease,  and  it  is  further  known  that  such  organisms,  or  some  of 
them,  can  live  in  water  for  a  length  of  time  sufficient  to  pass  from 
the  place  where  they  enter  this  source  of  water  supply  to  another 
place  where  water  is  taken  up  for  domestic  uses,  is  it  difficult  to 
conceive  that  some  of  the  people  who  drink  this  water  at  the  sec- 

*  Micro-organisms  in  Water,  by  Percy  and  Grace  Frankland,  London,  1894,  p.  131. 


INTR  OD  UC  TION.  9 

ond  place  may  take  these  organisms  into  their  s'ystem  and  lay  the 
foundation  of  disease  ? 

The  typhoid  bacillus  is  seldom  found  in  water,  and  the  failure 
to  find  it  is  too  often  taken  as  an  evidence  of  its  non-existence 
there.*  Dr.  T.  M.  Prudden,  however,  in  a  conversation  with  the 
author,  very  aptly  disposes  of  this  objection  by  stating,  "  If  I  were 
to  go  down  to  the  Battery  and  throw  a  coin  into  New  York  Har- 
bor, do  you  think  I  could  ever  find  it  again?"  The  coin  is  there; 
this  we  know  because  he  threw  it  into  the  water,  and  the  failure 
to  recover  it  cannot  be  taken  as  proof  of  its  non-existence  in  the 
bay,  but  as  an  indication  of  the  inefficiency  of  our  methods  of 
search.  The  same  argument  will  hold  good  in  case  of  failure  to 
find,  among  a  lot  of  vigorous  water  bacteria,  the  typhoid  or  any 
other  disease  germ  which  can  sustain  at  best  only  a  limited,  migra- 
tory existence  in  any  kind  of  water. 

It  is  also  held  by  opponents  of  the  water  transmission  of  infec- 
tious disease  that  the  evidence  is  lacking  of  the  actual  infection 
by  this  means.  Of  course  no  one  sees  the  germ  in  water,  and 
therefore  is  never  distinctly  aware  of  taking  it  into  the  system  in 
this  way ;  but  circumstantial  evidence  of  the  transmission  of  disease 
is  sometimes  as  potent  as  circumstantial  evidence  of  crime,  and 
must  be  accepted  accordingly. 

Upon  another  occasion  the  author  attempted  to  illustrate  the 
passage  of  disease  germs  from  one  point  to  another  in  water  in 
the  following  manner  :  — 

If  we  were  to  take  an  iron  pipe  two  or  three  feet  long,  put  a  marble  in 
one  end,  tilt  the  pipe  slightly,  and  make  the  marble  appear  at  the  other  end, 
you  would  say  that  the  marble  had  passed  through  the  pipe.  You  saw  it  put 
in  at  one  end,  and  in  due  time  it  appeared  at  the  other,  but  you  have  not  really 
seen  the  marble  passing  through  the  pipe.  The  inference,  however,  that  the 
marble  did  pass  through  the  pipe  is  correct ;  there  is  no  other  way  in  which, 
after  it  was  put  in  at  one  end,  it  could  reach  the  other. 

Let  the  marble  be  replaced  by  the  typhoid  bacillus,  and  let  the  pipe  be  a 
river,  or  a  lake,  or  a  reservoir  (as  at  Plymouth,  Penn..  in  1885).  We  can  prove 
by  examination  of  the  faeces  of  typhoid  patients  in  the  early  stages  of  the  dis- 
ease that  the  Eberth  germ  is  passing  into  our  sewers,f  and,  of  course,  into  our 

*   Twenty-fourth  Annual  Report  Massachusetts  State  Board  of  Health,  p.  531. 

t  "  Report  of  Royal  Commission  on  Metropolitan  Water  Supply,"  Minutes  of  Evidence, 


UNIVERSITY 


10  THE  PURIFICATION  OF   WATER. 

larger  sources  of  water  supply.  Eventually  we  will  find,  upon  post-mortem 
examination  of  persons  dying  in  the  early  stages  of  typhoid,  this  same  bacillus 
in  cultures  made  from  the  spleen  and  sometimes  from  the  intestine. 

How  has  it  come  there  ?  We  saw  it  go  into  the  sewer,  and  we  find  it  in 
the  body  of  the  typhoid  victim.  We  know  it  went  from  the  sewer  to  the  river, 
and  we  infer  that  the  river  was  the  carrier  of  the  germ.  We  did  not  see  it 
passing  through  the  water,  neither  did  we  see  our  marble  passing  through  the 
pipe.  We  know  that  the  marble  did  go  through  the  pipe,  and  I  think  the  evi- 
dence now  before  us  sufficiently  demonstrates  that  water  is  the  carrier  of  the 
typhoid  bacillus  from  the  sick  to  the  well. 

It  is  strange  that,  in  spite  of  our  exact  information  upon  the  matters  which 
convert  water  into  sewage,  we  are  so  willing  to  drink  this  dilute  mixture  of  filth. 
We  know  sewage  consists  of  the  wastes  from  the  household  and  factory,  and 
from  the  wash  of  the  streets  and  roads,  and  still  we  drink  the  mixture,  often 
with  no  misgiving,  and  rarely  indeed  with  complaint. 

At  the  same  time,  if  I  were  to  take  a  glass  of  distilled  water  which  is 
wholly  destitute  of  dangerous  organic  matter  and  bacteria,  and  in  your  presence 
put  into  it  even  the  slightest  amount  of  any  of  the  objectionable  wastes  which 
constitutes  sewage,  there  is  not  one  person  who  would  care  to  drink  it.  Senti- 
ment revolts  at  the  bare  suggestion  of  drinking  a  water  with  which  we  have 
seen  filth  mixed,  and  at  the  same  time  we  swallow  just  such  stuff  when  we 
drink  the  water  of  many  of  our  large  cities. 

The  whole  theory  of  water  purification  is  based  upon'  the  con- 
viction that  pure  water  cannot  create  a  disturbance  of  the  animal 
system  or  be  the  cause  of  ill  health,  and  that  certain  organic  mat- 
ter, or  the  products  of  organic  matter,  or  organisms  in  water,  is  the 
cause  of  certain  disorders,  or  are  concerned  in  the  etiology  of  spe- 
cific disease.  It  is  not  necessary  for  one  to  believe  in  the  germ 
theory  of  disease  before  he  can  become  an  advocate  of  pure  water 
supplies.  Long  before  the  ptomains  and  bacteria  were  known, 
certain  able  men  had  pointed  out  that  water  from  sources  appar- 
ently beyond  the  reach  of  pollution  was  more  healthful  to  drink 
than  water  which  was  known  to  be  polluted.  But  to  those  who  do 
believe  in  the  transmission  of  some  infectious  diseases  by  living 
organisms,  it  is  not  difficult  to  perceive  how  sewage-polluted 
waters  may  become  very  dangerous  distributers  of  infection. 

Pure  water  is  held  by  some  to  be  better  than  purified  water. 
This  undoubtedly  is  true ;  but  the  sources  from  which  pure  water 
is  available  are  so  few,  that  it  can  safely  be  assumed  if  cities  are  to 
have  pure  water,  they  must  adopt  artificial  means  to  make  it  so. 


INTRODUCTION.  11 

f  ' 
Thus  filtration  and  sedimentation  are  not  adopted  at  the  present 

time  by  any  city  simply  to  improve  the  appearance  of  water,  and 
make  it  more  welcome  to  the  bodily  senses,  but  as  distinct  safe- 
guards against  water-borne  diseases. 

No  one  should  be  deceived  upon  the  influence  of  sedimentation 
or  filtration  of  polluted  waters.  These  means  never  have  rendered, 
and  probably  never  will  render,  such  waters  pure  ;  but  they  can  be 
devised  and  operated  in  such  a  manner  that  nearly  every  natural 
water  can  be  rendered  less  likely  to  injure  the  human  system,  and 
at  a  cost  which  will  not  be  prohibitory  to  their  use.  A  claim  such 
as  is  sometimes  put  forth,  that  the  water  from  the  filters  of  Lon- 
don has  not  or  cannot  be  the  cause  of  typhoid  fever,*  cannot  be 
universally  admitted. 

Organisms  larger  than  the  typhoid  bacillus  have  repeatedly 
been  detected  in  the  filtered  London  water  ;  f  and  while  the  typhoid 
bacillus  has  not  been  found  among  them,  neither  has  it  been  found 
upon  careful  investigation  in  the  raw  water  before  it  has  gone  to 
the  filters. :f  (According  to  Dr.  G.  Sims  Woodhead,§  it  has  never 
been  found  in  any  rapidly  flowing  river.)  At  the  same  time,  with 
greater  care  in  operation  of  the  filters,  and  with  improved  methods 
of  water  analysis  and  higher  standards  of  purity,  the  typhoid  rates 
of  London  have  shown  a  marked  decline. 

Thus  for  the  decade  1861-1870  ||  the  annual  typhoid  fever 
death  rate  for  London  was  90  per  100,000  of  population.  For  the 
following  decade  the  annual  typhoid  fever  death  rate  was  24  per 
100,000  of  population,  and  for  the  decade  ending  with  1890  the 
annual  typhoid  fever  death  rate  was  19  per  100,000  of  population. 

During  the  seven  years  ending  Dec.  31,  1896,  the  average 
annual  typhoid  fever  death  rate  for  London  was  14.4  per  100,000 
of  population,  or  was  then  one-sixth  of  the  rate  which  prevailed 
thirty  years  before.  This  remarkable  reduction  in  the  typhoid 
rates  cannot  be  credited  to  improvements  in  the  filters,  so  much  as 

*  "  Report  of  Royal  Commission  on  Metropolitan  Water  Supply,"  1893,  Minutes  of  Evi- 
dence, p.  404 ;  also  Potable  Water,  by  Floyd  Davis.  New  York,  1891,  p.  40. 
f  Analytical  Investigation  of  London  Water  Supply,  1896,  p.  10. 
|  "  Report  Royal  Commission,"  Mimdes  of  Evidence,  p.  405. 
§  Ibid.,  p.  505. 
||  Engineering  Record,  Oct.  27,  1894. 


12  THE   PURIFICATION  OF   WATER. 

to  a  better  knowledge  of  how  they  should  be  operated,  and  to  the 
methods  of  water  analysis  developed  during  the  past  fifteen  years. 

Thirty  years  ago  the  London  filters  were  operated  to  secure  a 
clarified  water,  clear  water  seeming  at  that  time  to  mean  pure 
water,  or  water  safe  for  drinking  and  other  dietetic  uses.  We  know 
better  now,  and  limpidity  is  no  longer  taken  as  an  evidence  of 
purity  in  water. 

When  we  consider  that  the  death  rate  from  typhoid  fever  has 
been  as  low  as  three  persons  per  100,000  of  population  in  Munich 
(1892),  while  it  has  been  as  high  as  154  persons  per  100,000  of 
population  in  Chicago  (1891),  the  most  obtuse  must  admit  that 
there  is  something  wrong  in  our  sanitary  works  or  regulations 
which  will  permit  of  a  death  rate  from  typhoid  fever  in  any  city 
of  this  country  fifty  times  as  great  as  that  of  a  certain  city  in 
Europe.  While  the  Munich  rate  is  very  low,  still  it  is  not  excep- 
tional, as  is  shown  by  the  following  rates  for  that  city,  Berlin,  and 
Vienna :  — 

DEATHS   PER   100,000  OF   POPULATION   FROM   TYPHOID   FEVER. 
YEAR,  1890.  1891.  1892.          1893.  1894.         1895.        1896. 

Munich,  8  7  3  15         2-3         3  3 

Berlin,  9  10  8  9  455 

Vienna,  9  6  8  7  565 

Now  compare  these  rates  for  the  same  years  with  those  of 
three  cities  of  the  United  States. 

DEATHS   PER   100,000  OF   POPULATION   FROM   TYPHOID   FEVER. 
YEAR,  1890.  1891.  1892.  1893.          1894.        1895.         1896. 

Chicago,  92         154         106  45         31         32         46 

Pittsburg,  .   .         100         100         111         56         77         61 

Louisville,  88  81  72  84         72         77         45 

Vienna  and  Munich  are  supplied  with  the  purest  of  natural 
waters  from  mountain  springs,  and  the  city  of  Berlin  takes  its 
supply  from  the  River  Spree  and  Lake  Tegel,  the  waters  of  both 
being  passed  through  artificial  sand  filters  before  they  are  served 
to  the  consumers. 

In  comparing  the  typhoid  fever  rates  of  American  and  German 
cities,  perhaps  some  allowance  should  be  made  for  the  difference 


INTRODUCTION.  13 

in  habits  of  the  populations  of  the  respective  localities.  Thus 
Munich  is  said  to  be  one  of  the  greatest  beer-drinking  centers  of 
the  world,  the  consumption  of  this  beverage  having  at  one  time 
reached  as  high  as  one  hundred  and  twenty-five  gallons  per  capita 
per  annum  ;  and  it  is  possible  that  the  low  typhoid  fever  rates 
from  the  German  cities  may  be  due  in  part  to  the  general  absti- 
nence of  the  populations  from  the  public  water  for  drinking  pur- 
poses. 

If  it  be  true  that  the  low  typhoid  fever  rates  of  certain  cities 
in  Europe  are  due  to  the  general  use  of  beer  and  wine  as  beverages 
instead  of  water,  then  this  emphasizes  the  fact  that  a  typhoid  pol- 
luted drinking-water  is  the  principal  cause  of  the  high  typhoid 
fever  rates  in  cities  in  this  country,  and  makes  it  seem  remarkable 
that  cities  like  Munich,  Vienna,  and  The  Hague,  for  examples, 
where  the  typhoid  rates  are  very  low,  and,  as  some  people  claim, 
water  is  not  regarded  as  a  proper  thing  to  drink,  should  pay  so 
much  attention  to  the  quality  of  their  public  water  supplies. 

Why  should  Vienna,  for  instance,  be  at  such  great  expense  to 
bring  water  from  the  Alps,  distant  sixty-five  miles,  if  it  is  not  to 
be  used  for  dietetic  purposes,  when  the  water  of  the  Danube  will 
meet  every  other  requirement  quite  as  well  as  this  "  Schneeberg 
water,"  and  can  be  obtained  at  a  fraction  of  the  cost  involved  in 
the  scheme  of  works  by  which  that  city  is  now  supplied  ? 

The  usual  manner  of  introducing  the  typhoid  germ  into  the 
human  system  is  by  infected  drinking-water ;  therefore  every  city 
should  regard  it  as  a  duty  to  itself  to  see  that  the  water  distributed 
for  drinking  and  other  dietetic  purposes  is  not  the  carrier  of  the 
typhoid  bacillus  or  of  the  organism  productive  of  typhoid  fever. 

Much  has  been  written  upon  the  subject  of  water  supply  and 
the  dangers  of  polluted  waters  to  health,  much  also  has  been  writ- 
ten upon  methods  of  purifying  polluted  waters,  and  doubtless  much 
remains  to  be  written  upon  all  these  subjects  ;  but  from  the  pres- 
ent view,  it  can  be  safely  stated  that  whenever  a  steady,  vigorous 
effort  is  made  by  all  municipalities  to  supply  their  citizens  with 
water  up  to  the  highest  standard  attainable  by  practical  means, 
that  the  case  and  death  rate  from  water-borne  diseases  will  sink  so 
low  as  to  be  no  longer  the  cause  of  alarm. 


14  THE   PURIFICATION  OF   WATER. 


CHAPTER    II. 

SOURCES    OF   PUBLIC   WATER   SUPPLY. 

THE  sources  of  public  water  supply  for  cities  are  rivers,  natural 
lakes,  large  impounding  reservoirs,  usually  at  elevations  sufficient 
to  furnish  a  supply  to  cities  by  gravity  ;  springs,  shallow  dug  wells, 
often  carried  into  the  drift  a  depth  not  much  in  excess  of  the  max- 
imum suction  lift  of  pumping  machinery  ;  and  deep  driven  wells. 
Some  of  the  latter  may  be  artesian,  and  supply  into  large  wells  or 
reservoirs  from  which  the  suction  of  the  pumps  is  taken,  or  may 
be  connected  directly  with  the  pumps. 

Of  course  all  water  supply  must  be  derived  from  the  rainfall, 
whether  it  be  taken  from  streams,  lakes,  impounding  reservoirs,  or 
from  springs  and  wells ;  but  the  water  supply  of  any  particular  lo- 
cality may  not  be  wholly  dependent  upon  the  local  rainfall.  This 
is  true  where  the  source  of  supply  is  a  river  draining  a  large  terri- 
tory, or  where  it  is  obtained  from  springs  or  deep  wells.  In  local- 
ities where  the  outcrop  or  denuded  rock  formation  is  destitute  of 
soluble  materials,  such  as  lime  and  magnesia,  the  water  gathered  in 
impounding  reservoirs  will  be  quite  as  soft  as  that  of  domestic  cis- 
tern water  collected  from  the  roof  of  a  residence  or  other  building. 

In  the  limestone  regions  surface  water,  while  running  off  to  im- 
pounding reservoirs,  comes  in  contact  with  the  outcrop  of  rock,  and 
takes  up  some  of  the  lime  and  magnesia  ;  and  the  impounded  water 
will  be  harder  than  domestic  cistern  water.  River  water  ip  hardness 
and  quality  will  depend  entirely  upon  the  character  of  the  water- 
sheds from  which  it  is  derived,  and  the  materials  with  which  it 
may  come  in  contact  after  it  has  reached  the  channel  of  discharge. 

Aside  from  the  direct  sewage  pollution  of  the  large  rivers  of 
the  world  by  the  refuse  from  the  civilization  which  is  collected 
upon  their  banks,  there  is  another  pollution,  due  to  the  contact  of 
the  water  while  running  off,  with  organic  matter  from  various 


SOURCES   OF  PUBLIC    WATER  SUPPLY.  15 

sources  collected  upon  the  watershed.  Some  of  this  may  be  car- 
ried in  solution  by  the  runoff  of  rainfall  into  the  channel,  while 
other  portions  may  be  carried  along  in  mechanical  suspension. 

The  objection  to  a  polluted  river  or  lake  water  is  not  limited 
to  the  amount  of  sewage  which  it  may  contain.  It  may  be  posi- 
tively objectionable  from  a  sanitary  point  of  view  by  reason  of 
organic  matter,  and  possibly  pathogenic  bacteria,  which  may  come 
into  such  water  from  the  surface  drainage  of  the  tributary  water- 
shed. If  the  opinion  entertained  by  Professor  E.  Ray  Lankester, 
that  the  bacillus  of  typhoid  fever  may  be  an  exacerbated  form  of 
b.  coli  communis  (a  pathogenic  germ  which  is  known  to  be  given 
off  in  the  dejecta  of  sheep  and  other  domestic  animals,  as  well  as 
of  man),  be  confirmed  by  later  investigation,  then  it  is  very  clear 
that  the  special  sewage  pollution  of  a  drinking-water  supply  is  not 
essential  for  the  propagation  of  typhoid  fever,  and  that  there  will 
be  found  in  the  organic  matter  now  coming  into  streams  and  other 
sources  of  public  water  supply,  from  the  runoff  of  rainfall  or  sur- 
face drainage,  all  the  elements  essential  for  the  development  of 
this  particular  disease. 

(It  does  not  appear  that  there  are  many  who  share  the  opinion 
with  Professor  Lankester  that  b.  typhosus  is  an  exalted  form  of  the 
colon  bacillus,  but  time  may  demonstrate  that  his  view  is  correct  ; 
and  if  it  does,  light  will  be  shed  upon  some  of  the  apparently  inex- 
plicable phenomena  connected  with  certain  epidemics  of  typhoid 
fever.) 

Rivers  which  receive  the  drainage  of  cities  or  towns  on  their 
banks  and  the  banks  of  their  tributaries,  even. in  the  absence  of 
known  sewage  pollution,  cannot  be  regarded  as  uncontaminated 
sources  of  public  water  supply ;  and  although  it  may  be  difficult  to 
show  the  presence  of  organic  matter  or  of  bacteria  inimical  to 
health,  still  there  will  always  be  an  amount  of  organic  matter  in 
such  rivers  in  process  of  decomposition,  which  may  give  rise  to  dis- 
orders of  the  human  system,  even  though  they  may  not  be  the 
cause  of  specific  disease. 

It  is"  probable  that  surface  water  can  be  impounded  in  reser- 
voirs from  watersheds  at  elevations  so  high  as  to  avoid  pollution 
from  all  sources  but  the  atmosphere  ;  and  such  water,  although  still 


16  THE   PURIFICATION  OF   WATER. 

open  to  the  influence  of  decomposing  organic  matter  found  every- 
where in  nature,  will  always  be  purer  than  water  collected  in 
rivers,  lakes,  and  ponds  on  the  low  lands. 

Sources  of  water  supply  at  high  elevations  with  a  yield  so  large 
as  to  satisfy  the  requirements  of  cities  are  of  rare  occurrence ;  and 
even  in  the  few  cases  where  such  exist,  the  distance  from  the  mu- 
nicipality to  be  supplied  is  so  great  as  to  make  the  development 
and  utilization  prohibitory  for  any  but  the  larger  cities.  The  city 
of  Vienna  derives  its  supply  of  public  water  at  the  present  time 
altogether  from  large  springs  found  in  the  Schneeberg,  a  portion  of 
the  Austrian  Alps,  and  brings  this  water  through  a  conduit  sixty- 
five  miles  long  to  the  city.  The  city  of  Munich  obtains  its  water 
supply  from  similiar  springs  in  the  Mangfall  valley  of  the  Bavarian 
Alps.  A  few  of  the  smaller  municipalities  in  this  country  derive 
their  public  water  supply  from  springs  or  streams  at  high  eleva- 
tions in  sparsely  settled  or  wild  districts.  But  sources  of  this  char- 
acter are  not  available  by  the  majority  of  the  cities  of  this  or  any 
country ;  and  recourse  must  be  had  to  such  sources  as  are  avail- 
able, and  these,  as  stated  at  the  outset  in  this  chapter,  are  rivers, 
lakes,  ponds,  creeks,  and  dug  and  driven  wells. 

Considering  rivers  as  constituting  by  far  the  largest  source  of 
water  supply  for  municipal  corporations,  it  may  be  accepted  as  an 
axiom  "  that  no  river  is  carrying  during  times  of  flood  a  water 
which  is  fit  for  drinking  purposes  except  it  first  be  artificially  puri- 
fied ; "  and  if  such  rivers,  in  addition  to  the  pollution  which  cannot 
be  avoided  by  the  runoff  of  rainfall  on  the  drainage  areas,  receive 
the  sewage  of  towns  and  cities,  the  water  is  undoubtedly  not  fit 
for  drinking  and  culinary  uses  until  it  has  been  dealt  with  in  such 
a- manner  as  to  render  it  innocuous  to  health.  It  is  frequently  as- 
serted or  implied  in  text-books  and  reports  on  sewage  and  sewage 
disposal,  that  the  noxious  properties  of  sewage  are  destroyed  by 
proper  dilution  ;  but  when  sewage  is  the  carrier  of  disease  germs, 
dilution  cannot  remove  them.  It  will  reduce  the  number  of  such 
germs  per  unit  of  volume  of  the  mixed  sewage  and  water  ;  but  the 
germs  are  still  there,  and  if  taken  into  the  system  through  drink- 
ing-water may  produce  just  as  serious  results  to  as  many  people 
as  if  no  dilution  had  occurred. 


SOURCES   OF  PUBLIC    WATER  SUPPLY.  17 

Dilution  of  sewage  undoubtedly  reduces  ttfe  chances  of  any 
single  individual  imbibing  a  fatal  germ  in  drinking  the  water ;  but 
the  germ  itself  will  be  just  as  dangerous,  and  in  one  aspect  of  the 
case  may  be  more  dangerous,  when  imbibed. 

It  is  well  known  to  bacteriologists  engaged  in  the  analysis  of 
drinking-waters  that  the  typhoid  bacillus,  for  instance,  will  live 
for  the  greatest  length  of  time  in  a  water  devoid  of  other  kinds 
of  bacteria,  and  will  live  for  the  least  length  of  time  in  a  con- 
centrated sewage  rich  in  the  bacteria  of  putrefaction.  The  dilu- 
tion of  sewage  therefore  reduces  the  number  of  bacteria  per  unit 
of  volume  of  the  water,  and  favors  the  vitality  of  the  typhoid 
bacillus.  Considering  that  some  of  the  bacteria  can  survive  for 
many  days  in  water  of  single  distillation  containing  naturally  but 
a  very  minute  amount  of  organic  matter,  it  will  not  be  difficult  to 
apprehend  the  possibility  of  a  high  dilution  of  sewage  distinctly 
favoring  the  longevity  of  the  typhoid  germ  ;  and  the  theory  that 
a  sewage-polluted  water  may  be  rendered  safe  for  drinking  pur- 
poses by  dilution  must  necessarily  neglect  this  fact.  Rivers  and 
their  tributaries  have  for  generations  been  the  receptacles  of 
sewage,  garbage,  and  all  the  wastes  of  civilization  ;  and  even  if  the 
water  came  into  these  channels  free  from  any  objectionable  matter, 
the  practice  of  communities  in  making  them  the  receptacles  of 
sewage  would  condemn  the  water  from  such  sources  as  altogether 
unfitted  for  drinking  and  some  other  uses.  This,  however,  is  well 
recognized,  not  only  in  England  and  other  countries  of  Europe, 
but  in  certain  portions  of  this  country  ;  and  steps  are  being  taken 
to  prevent  the  pollution  of  streams  by  the  refuse  of  organized 
communities. 

Considering  that  even  in  its  best  condition  the  water  of  a  river 
is  of  questionable  hygienic  quality,  one  can  appreciate  the  impor- 
tance of  a  disposal  of  sewage,  garbage,  and  other  wastes,  in  a  man- 
ner that  can  by  no  means  injure  sources  which  are  drawn  upon 
for  public  water  supply. 

Dr.  G.  Sims  Woodhead  *  says  :  — 

"  If  river  water  must  be  used,  every  possible  precaution  should  be  taken 
against  its  being  made  a  receptacle  for  unpurified  sewage.     It  is  almost  im- 
*  Report  Royal  Commission  on  Metropolitan  Water  Supply,  Appendix  C,  p.  491. 


18  THE   PURIFICATION  OF   WATER. 

possible  during  periods  of  flood  to  obtain  it  free  from  large  quantities  of  sur- 
face drainage,  but  it  should  be  insisted  that  in  ordinary  weather  there  should 
be  no  surface  drainage  directly  into  the  Thames  or  into  its  tributaries." 

According  to  Professor  Baumeister,*  we  can  safely  drink  a 
sewage-polluted  water  when  the  sewage  and  water  are  mixed  in 
certain  proportions,  depending  upon  the  amount  of  organic  matter 
in  the  sewage  and  of  that  previously  in  the  water.  But  he  depends 
altogether  on  chemistry  for  the  test  of  potability  of  the  water, 
when  it  is  well  known  that  chemistry  is  powerless  to  reveal  infec- 
tious properties  or  bacteria  in  the  water.  He  states  upon  German 
authority  that  water  may  carry  2^  grains  of  organic  matter  to  the 
gallon  and  still  be  potable.  Looking  at  the  question  from  a  chem- 
ical standpoint  this  may  be  true,  but  from  a  sanitary  standpoint 
any  organic  matter  in  drinking  water  known  to  be  from  a  sewage 
source  will  render  such  water  unsafe  for  drinking. 

The  statement  by  Professor  Baumeister  that  sewage  containing 
29.2  grains  of  organic  matter  to  the  gallon  may  be  mixed  with 
river  water  containing  1.2  grains  of  organic  matter  to  the  gallon, 
in  the  ratio  of  23  gallons  of  water  to  1  gallon  of  sewage,  and  the 
mixture  be  safe  for  drinking  purposes,  seems  to  me  to  be  very 
dangerous,  because  the  sewage  may  contain  the  germs  of  typhoid 
fever  which  no  amount  of  dilution  can  eliminate.  Moreover, 
advice  like  this,  instead  of  promoting  the  purity  of  water  supplies 
and  the  public  health,  is  calculated  to  injure  both. 

It  is  but  fair  to  state  that  Professor  Baumeister  is  looking  at 
the  matter  solely  from  the  standpoint  of  sewage  disposal  into 
running  streams  ;  and  it  is  doubtful  if  the  selfish  motive  of  ridding  a 
community  of  sewage  by  generally  the  easiest  and  cheapest  method 
should  be  allowed  to  prevail,  when  certain  disaster  to  those  who 
may  draw  their  drinking-water  from  the  stream  below  is  bound 
to  follow. 

In  another  paragraph  Professor  Baumeister  says  :  — 

"  The  objection  may  be  raised  to  these  computations  [relating  to  sewage 
dilution]  that  the  limiting  amounts  of  organic  matter  in  potable  water  was  not 
fixed  under  a  supposition  that  a  part  of  it  was  human  excrement." 

*  "  The  Quality  of  Water  Supplies,"  by  the  author,  Transactions  American  Society  of  Civil 
Engineers,  vol.  xxxii.,  p.  149  et  seq. 


SOURCES   OF  PUBLIC    WATER   SUPPLY.  19 

But  all  sewers  receive  some  human  dejecta  •  and  this  at  times 
may  contain  disease  germs,  and  these  germs,  mixing  with  a  so- 
called  potable  water,  are  dangerous.  Adapting  to  our  purpose  the 
memorable  words  of  Mr.  Lincoln,  any  water  likely  to  be  adopted 
for  drinking  purposes  may  be  safe  to  all  people  at  some  times, 
it  may  be  safe  to  some  people  at  all  times,  but  it  may  not  be  safe 
to  all  people  at  all  times  ;  and  the  protection  of  those  who  may  at 
some  time  be  susceptible  to  its  deleterious  influences  should  warn 
us  against  the  use  of  any  drinking-water  known  to  contain  organic 
matter  from  a  sewage  source. 

What  has  been  said  by  way  of  objection  to  rivers  and  their 
tributaries  as  sources  of  water  supply  will  apply  to  lakes  which 
receive  the  drainage  of  rivers  and  the  runoff  of  large  watersheds, 
with  the  reservation,  —  that  in  large  bodies  of  water  the  reduction 
of  organic  matter  by  subsidence  and  bacterial  action  will  proceed 
with  a  more  regular  rate  than  in  rivers.  In  support  of  this  prop- 
osition, the  experiments  of  Dr.  Miquel  upon  water  taken  from  the 
River  Seine  at  a  point  below  the  outfall  of  some  of  the  larger 
sewers  of  Paris  indicate  that  polluted  water  at  rest  through  a 
long  period  of  time  is  sufficient  to  reduce  the  organic  matter  to 
harmless  nitrates  and  nitrites,  and  remove  the  bacteria  altogether ; 
these  (as  organic  matter)  probably  disappearing  as  gases,  or  form- 
ing a  part  of  the  residual  compounds  of  nitric  or  nitrous  acid 
with  the  inorganic  bases. 

The  time  required,  however,  according  to  Dr.  Miquel,  is  very 
great ;  and  excepting  in  cases  of  very  large,  deep  bodies  of  water 
no  such  reduction  can  be  expected. 

The  experiments  of  Dr.  Miquel  have  not  taken  into  considera- 
tion the  seasonal  disturbances  of  large  bodies  of  water,  which 
occur  in  the  spring  and  autumn,  and  are  due  to  the  difference  of 
temperatures  of  the  layers  of  water  at  the  top  and  bottom  of 
large  lakes  and  reservoirs,  which  is  calculated  to  bring  organic 
matter  from  the  bottom  of  such  bodies  of  water,  and  distribute 
it  with  more  or  less  uniformity  throughout  all  the  layers,  from  the 
top  to  the  bottom.  Aside  from  these  seasonal  disturbances',  the 
fact  is  very  well  established,  that  there  is  a  species  of  purification 
going  on  steadily  in  all  large  bodies  of  water,  which  if  uninter- 


20  THE   PURIFICATION  OF   WATER. 

rupted  by  the  accession  of  fresh  organic  matter  from  the  runoff 
of  rainfall  and  the  discharge  from  sewage-polluted  rivers  and 
streams,  such  water  would  eventually  become  absolutely  pure. 
This  of  course  assumes  a  regimen  for  lakes  and  impounding  reser- 
voirs as  well  as  the  lesser  quiescent  bodies  of  water  which  is  not 
found  in  practice,  and  in  the  author's  opinion,  the  time  has  ar- 
rived to  treat  such  sources  of  public  water  supply  in  the  same 
manner  as  we  are  preparing  to  treat  the  water  of  polluted  rivers  ; 
for  the  same  agencies  which  are  operating  to  increase  the  natural 
contamination  of  river  waters  are  also  operating  to  produce  a 
contamination  of  our  lake  and  impounded  waters,  the  difference 
being  more  in  degree  than  in  kind  of  pollution. 

In  his  testimony  before  the  Royal  Commission  on  Metropolitan 
Water  Supply,  Dr.  William  Odling,*  one  of  the  official  analysts 
of  the  water  supplied  by  the  London  companies,  expressed  the 
opinion  that  no  river  or  lake  water  was  potable  until  after  filtra- 
tion, and  laid  particular  stress  upon  the  necessity  of  filtering  lake 
water  before  it  was  used  for  dietetic  purposes. 

This  fact  is  well  illustrated  in  the  experience  of  the  city  of 
Zurich,  which  takes  its  water  from  Lake  Zurich,  a  large  body  of 
-water  at  high  elevation  in  the  Swiss  Alps,  and  supposed  for  many 
years  to  be  an  ideal  source  of  public  water  supply ;  yet  it  is  well 
known  that  alarming  typhoid  fever  rates  have  been  traced  to  the 
polluted  water  of  the  lake,  and  for  a  number  of  years  no  water  has 
been  taken  by  that  city  until  it  has  first  been  passed  through  a 
system  of  sand  filters.  It  is  possible  that  no  natural  water  supply 
in  the  United  States  is  superior  to  that  of  Lake  Zurich,  lying  as 
it  does  far  above  the  usual  sources  of  contamination  ;  but  despite 
this  fact,  we  find  that  even  this  body  of  water  is  not  located  high 
enough,  or  far  enough  away  from  the  habitation  of  man,  to  insure 
its  purity  through  all  time ;  and  if  it  be  essential  to  filter  the 
water  of  Lake  Zurich  before  it  is  delivered  for  drinking  and  other 
domestic  purposes,  why  should  it  not  be  so  with  any  natural  body 
of  water  now  used  as  a  source  of  public  supply  in  this  country  ? 

The  commonly  accepted  opinion  that  sewage-polluted  streams 
are  capable  of  self-purification  by  flow  through  a  reasonable  dis- 

*  Minutes  of  Evidence,  p.  388. 


SOURCES   OF  PUBLIC    WATER  SUPPLY.  21 

. 

tance  can  no  longer  be  seriously  entertained.  The  Sixth  Report 
of  the  Rivers  Pollution  Commission  of  England  contains  the  con- 
clusion "  that  there  is  no  river  in  the  United  Kingdom  which  is 
long  enough  to  purify  itself  of  sewage  received  at  its  source  ; "  and 
it  might  have  added,  nor  in  any  other  country  where  fresh  acces- 
sions of  sewage  are  being  constantly  received  by  rivers  from  cities 
on  their  banks. 

It  is  often  held  that  aeration  of  polluted  waters  has  a  beneficial 
effect  on  their  quality.  This  theory,  however,  is  successfully 
disputed  by  the  experiments  of  Dr.  T.  M.  Drown  for  the  Massa- 
chusetts State  Board  of  Health.  These  experiments  show  no 
oxydizing  effect  of  aeration  on  the  suspended  organic  matter  in 
polluted  waters,  and  a  water  must  be  very  heavily  charged  with 
sewage  before  the  dissolved  oxygen  per  unit  of  volume  of  the 
water  becomes  so  low  as  to  have  an  injurious  effect  on  the  bac- 
teria concerned  in  the  destruction  of  organic  matter.  Aeration 
may  impart  "life,"  as  it  were,  to  water;  but  it  cannot  be  said  to 
have  any  marked  influence  on  its  quality. 

It  is  probable  that  the  self-purification  of  rivers  occurs  in  the 
same  way  as  in  lakes,  —  by  subsidence  of  the  heavier  organic  matter, 
and  by  the  destructive  action  of  the  bacteria ;  and  these  effects,  as 
shown  by  the  experiments  of  Dr.  Miquel  on  the  water  of  the  River 
Seine,  require  considerable  time,  and  are  probably  assisted  by  a 
quiescent  state  of  the  water,  —  two  conditions  not  consistent  with 
rivers  of  steep  or  moderate  slope,  and  exposed  from  point  to  point 
in  their  course  to  renewals  of  organic  matter  from  sewage  and 
drainage  sources. 

Certain  eminent  investigators  still  hold  to  the  opinion  that  self- 
purification  of  polluted  streams  really  occurs,  and  that  this,  com- 
bined with  dilution  of  the  sewage  by  accession  of  fresh  water,  will 
be  sufficient  to  purify  a  contaminated  water  until  it  is  fit  for  drink- 
ing. But  no  reliance  can  be  placed  on  self-purification  ;  and  if  cities 
are  to  have  a  satisfactory  drinking-water  from  a  source  of  known 
pollution,  it  must  be  made  satisfactory  by  some  artificial  means. 

Impounding  reservoirs,  such  as  constitute  the  sources  of  sup- 
ply for  New  York  and  Liverpool,  are  not  open  to  the  same  degree 
of  pollution  as  lakes  and  rivers  ;  but  excepting  the  drainage-ground 


22  THE   PURIFICATION  OF   WATER. 

of  such  sources  is  laid  waste,  and  rendered  free  from  all  animal 
influences,  even  such  water  cannot  be  regarded  as  complying  with 
the  highest  standard  of  hygiene. 

Dug  wells  sunk  a  short  distance  in  the  drift  are  open  to  pollu- 
tion from  surface  drainage ;  and  such  should  never  be  adopted  for 
a  public  supply  except  they  be  far  removed  from  human  habita- 
tion, and  then  only  when  the  materials  through  which  they  are 
dug  contains  a  thick  stratum  of  impervious  clay  overlying  the 
water-bearing  sand  or  gravel.  Wells  of  this  character  usually  are 
limited  in  depth  to  the  suction  lift  of  pumps,  and  intercept  water 
only  in  the  upper  layers  of  the  soil. 

Sometimes  shallow  wells  intercept  veins  of  water  gathered  on 
distant  and  higher  watersheds,  and  the  water  may  have  been  sub- 
jected to  efficient  natural  purification  before  it  reaches  the  well. 
In  such  cases,  if  the  materials  of  the  drift  and  the  manner  of 
constructing  the  well  are  such  as  to  effectually  exclude  all  local 
surface  drainage,  the  water  may  be  of  high  quality  and  altogether 
safe.  It  is  not  an  easy  matter,  however,  to  determine  from  what 
source  intercepted  ground  water  has  come ;  and  shallow  well  water 
should  no't  be  used  for  public  supply  until  repeated  bacterial  and 
chemical  tests,  through  a  reasonable  length  of  time,  have  shown 
no  possible  pollution  by  sewage  or  local  surface  drainage. 

If  it  be  true  that  the  typhoid  fever  death  rates  in  any  large 
community  is  a  reliable  index  of  the  quality  of  the  public  water 
supply,  then  we  are  bound  to  admit  that  our  great  lakes  (sewage 
polluted  as  they  are,  especially  in  the  neighborhood  of  such  cities) 
cannot  be  accepted  as  satisfactory  sources  of  public  water  supply, 
excepting  the  water  be  subjected  to  careful  filtration  before  it  is 
supplied  to  the  consumers. 

TYPHOID   FEVER    DEATH   RATES   PER   1OO,OOO   OF   POPULATION   LIVING. 
CITIES    USING    LAKE    WATER. 


Chicago,  (average  for  seven  years  ending  December   1896),       71 

Milwaukee,  29 

Detroit,  "        "        "         "                                                        30 

Cleveland,  46 

Buffalo,  «        "     sup        "                                                        34 

Average,  42 


SOURCES   OF  PUBLIC    WATER  SUPPLY.  23 

CITIES    USING    RIVER    WATER. 

Pittsburg,       (average  for  seven  years  ending  December,  1896),  84 

Philadelphia,          "        "         «         "            "               "               «  45 

Cincinnati,              "        "         "         «           "               "               "  49 

Louisville,               "        "        "         "           "              "               "  74 

St.  Louis,                "        "        "         "           "              "               «  39 

Average,  58 

CITIES    USING   FILTERED    RIVER    WATER. 

London,          (average  for  seven  years  ending  December,  1896),  14.4 

Berlin,  "  "        "  "  "  "              "  7.1 

Rotterdam,  «  "        «  "  "  «              »  5.7 

Hamburg,  "  «  four  "  »  "               «  9.7  * 

Hamburg,  "  "  three  "  "  "              "  7.0 

Altona,  "  "  six  "  "  »  1895  26.8 

Average,  12.2 

In  addition  to  the  causes  of  pollution  of  river  and  lake  waters 
previously  mentioned,  certain  objectionable  properties  are  some- 
times imparted  to  the  water  by  the  subsoil  drainage  from  irrigated 
and  fertilized  land.  Thus  the  salts  in  phosphates  and  other  ferti- 
lizers, and  the  ammonias  from  land  laid  with  stable  compost,  are 
taken  up  by  the  water  percolating  through  the  arable  ground,  and 
eventually  find  their  way  by  lateral  movement  through  the  soil 
into  sources  of  water  supply.  While  the  simple  addition  of  organic 
matter  to  water  by  this  cause  may  never  be  very  objectionable  in 
itself,  there  is  an  objection  to  imparting  properties  to  water  which 
may  encourage  the  growth  and  development  of  some  of  the  patho- 
genic bacteria,  and  the  increase  of  the  alkalinity  of  water  has 
already  been  pointed  out,  at  least  in  one  instance,  as  the  cause  of 
the  rapid  development  of  the  cholera  bacillus. f  A  professor  of 
chemistry  in  one  of  our  Western  universities  has  stated  to  the 
author,  that  from  his  investigations  typhoid  fever  seems  to  be 
most  persistent  in  those  districts  where  the  water  is  abnormally 
high  in  nitrates  and  nitrites,  and  it  is  altogether  probable  that  the 
subsoil  drainage  of  farm  lands  is  concerned  in  maintaining  this 
condition  of  nitrates  and  nitrites  in  certain  water  sources  which 
are  drawn  upon  for  domestic  supply. 

*  Filters  put  in  service,  May,  1893. 

t  Micro  Organisms  in  Water,  by  P.  F.  &  G.  C.  Frankland,  London,  1894,  p.  300  (Ham- 
burg Epidemic,  1892). 


24  THE   PURIFICATION  OF   WATER. 

The  author  does  not  propose  at  this  time  to  discuss  the  influ- 
ence of  nitrates  or  nitrites  on  the  vitality  of  the  typhoid  bacillus, 
and  will  simply  suggest  that  what  has  hitherto  been  regarded  as  a 
matter  of  no  consequence  in  connection  with  a  public  water  sup- 
ply may  become,  in  the  light  of  future  developments  on  the  biology 
of  this  germ,  a  question  of  grave  concern.  Thousands  of  acres  of 
farm  land  are  to-day  being  annually  treated  with  natural  and  arti- 
ficial fertilizers,  and  the  subsoil  water  from  such  land  is  going  into 
some  of  our  sources  of  water  supply  with  possibly  no  advantage  to 
the  water.  If  the  opinion  now  held  by  some  investigators  be  con- 
firmed by  later  experience,  —  that  the  addition  to  water  of  certain 
salts  from  these  fertilizers  is  favorable  to  the  growth  of  the  ty- 
phoid bacillus,  —  then  a  new  and  difficult  problem  will  be  pre- 
sented in  connection  with  the  other  and  well-recognized  sources 
of  pollution  by  surface  drainage  and  urban  sewage. 

It  is  altogether  feasible  to  provide  against  the  direct  contami- 
nation of  water  supplies  from  sewage  by  requiring  all  communities 
to  treat  this  in  such  manner  that  the  effluent  shall  conform  to  a 
given  standard  of  hygiene  before  it  is  permitted  to  go  into  our 
water  courses,  lakes,  and  ponds  ;  but  the  objection  to  surface  and 
subsoil  drainage  cannot  be  so  easily  disposed  of.  In  the  light  of 
the  present  information  upon  the  subject,  we  are  safe  in  assuming 
that  any  dangers  to  our  sources  of  water  supply  from  these  causes 
must  be  met  by  treatment  of  the  water  after  such  pollution  has 
occurred,  rather  than  by  efforts  to  prevent  pollution  ;  and  if  the 
theory  and  operation  of  sand  filtration  be  accepted  as  established 
conditions,  and  not  as  propositions  still  to  be  proven,  we  can  as- 
sume that  the  filtrate  may  be  brought  to  any  practical  standard  of 
hygiene  without  regard  to  the  quality  of  the  water  from  which  it 
is  obtained. 

Filtration  to  be  successful  must  be  able  to  meet  all  the  vary- 
ing conditions  of  any  water,  and  render  a  filtrate  which  will  be 
substantially  unvarying  in  quality.  While  the  quality  of  the  water 
applied  to  the  filter  may,  and  in  many  cases  will  vary  between 
wide  limits,  the  quality  of  the  filtered  water  must  be  practically 
uniform.  The  London  standard  of  bacterial  quality  of  the  filtered 
water  is  one  hundred  bacteria  per  cubic  centimeter  of  the  filtrate ; 


SOURCES   OF  PUBLIC    WATER   SUPPLY.  25 

and  while  the  counts  are  usually  much  lower  than  this,  under  no 
condition  can  the  filtered  water  show  more  than  this  number  with- 
out passing  the  limits  there  assigned  for  potable  water. 

The  London  standard  is  thus  not  based  upon  the  relation  of 
the  numbers  of  bacteria  in  the  filtrate  to  the  numbers  of  bacteria 
in  the  unfiltered  water,  but  is  an  absolute  standard,  to  which  the 
filtered  water  must  conform  without  regard  to  the  bacterial  con- 
dition of  the  water  as  it  comes  from  its  natural  source.  The 
standard  of  filtered  water,  like  all  standards,  is  an  arbitrary  one, 
and  is  fixed  upon  the  judgment  of  men  best  informed  upon  the 
subject ;  and  as  standards  of  quality  for  any  substance  are  rarely 
placed  beyond  the  reach  of  practical  methods,  it  is  reasonable  to 
infer  that  with  increased  experience  and  knowledge  of  filtration, 
and  with  improved  results  from  the  application  of  research  and 
experiment,  that  the  standard  of  water  quality  will  be  placed  higher 
and  higher,  until  the  limit  of  practical  methods  is  attained. 

That  one  hundred  bacteria  or  colonies  per  cubic  centimeter  of 
filtered  water  is  not  a  rare  or  difficult  achievement  is  well  attested 
by  the  operation  of  the  Chelsea  filters,  which  according  to  Dr.  E. 
Frankland,  the  official  analyst  of  the  water  supplied  by  the  London 
companies,  furnished  a  filtrate  that  contained  for  the  year  1896, 
omitting  the  month  of  June,  an  average  of  21  colonies  of  bacteria 
per  cubic  centimeter  of  water,  the  numbers  being  as  high  as  55  in 
December  and  as  low  as  2  in  September,  while  the  river  water  at 
Hampton  Court,  the  point  of  intake  for  the  Chelsea  water  company, 
contained  so  few  as  1,740  bacteria  per  cubic  centimeter  in  August, 
and  as  many  as  160,000  bacteria  per  cubic  centimeter  in  December 
of  that  year. 

No  operation  suffers  by  care  in  its  performance ;  and  to  the 
caution  as  well  as  skill  displayed  in  the  operation  of  the  London 
filters  is  due  the  low  numbers  of  bacteria  in  the  filtered  water, 
and  the  low  typhoid  fever  rates  of  that  metropolis. 

When  failures  have  been  recorded  in  the  filtration  of  public 
water  supplies,  it  can  be  set  down  as  being  due  to  ignorance  or 
carelessness  in  proportioning  the  filters,  or  to  gross  mismanage- 
ment in  their  operation.  Many  attempts  have  been  made  to  pass 
water  through  sand  filters  at  rates  which  were  not  only  beyond 


26  THE   PURIFICATION  OF   WATER. 

all  precedent,  but  beyond  reason.  Thus  a  certain  water  company, 
which  is  now  supplying  a  city  of  over  150,000  population  east  of  the 
Rocky  Mountains,  has  attempted  to  filter  a  polluted  water  at  the 
rate  of  nearly  200,000,000  gallons  per  acre  per  day  ;  a  rate  one 
hundred  times  greater  than  that  for  the  London  filters,  and  has 
assumed  that  this  water  was  fit  to  go  to  its  consumers,  and  be 
used  for  drinking  and  other  dietetic  purposes.  The  vertical  rate  of 
filtration  in  the  London  and  most  of  the  European  works  seldom 
exceeds  8  to  10  feet  per  day  of  twenty-four  hours,  while  the  esti- 
mated rate  for  this  improved  system  of  filtration  in  the  Western 
city  was  600  feet  per  day,  or  5  inches  per  minute.*  Natural  fil- 
tration through  the  pervious  materials  of  the  drift  is  variously  stated 
to  occur  at  rates  of  7  to  40  feet  per  day  of  twenty  four  hours. 

Under  circumstances  like  these  it  is  not  surprising  that  the 
water  was  really  not  filtered  at  all,  and  went  through  the  mains  to 
the  consumers  with  no  actual  improvement  in  its  hygienic  quality. 

The  typhoid  fever  rates  for  that  city  were  abnormally  high  for 
the  last  six  months  of  the  past  year  (1896),  and  the  health  officials 
very  justly  charged  the  unusual  rates  to  this  sham  filtration. 

In  another  Western  city  an  improved  natural  filter  was  recently 
started  to  operate  at  rates  of  22,000,000  to  44,000,000  gallons  per 
acre  per  day,  with  very  satisfactory  results,  according  to  report  of  the 
designer.  No  analysis  of  the  water  before  and  after  it  passed  this 
filter,  nor  records  of  the  influence  of  such  water  filtration  on  the 
health  of  the  consumers,  are  available  by  the  author ;  but  it  cannot 
be  doubted  that  filtration  under  these  conditions  is  really  no  filtra- 
tion at  all,  and  is  calculated  to  hinder  rather  than  encourage  proper 
efforts  in  the  direction  of  water  purification  by  practical  methods. 

If  the  bacterial  contents  of  a  water  is  a  fair  test  of  quality,  then 
driven  wells  sunk  to  moderate  depths  in  the  drift  do  not  always 
intercept  thoroughly  filtered  water.  Professor  Sedgwick,  of  the 
Massachusetts  State  Board  of  Health,  has  tested  the  water  of  a 
number  of  driven  wells  in  the  vicinity  of  Boston,  with  bacterial 
counts  as  high  as  1,376  per  cubic  centimeter,  while  the  water  from 
other  driven  wells  was  shown  to  contain  so  few  as  30  bacteria  per 
cubic  centimeter. 

*  Transactions  American  Society  of  Civil  Engineers,  vol.  xxxi.,  p.  159. 


SOURCES    OF  PUBLIC    WATER   SUPPLY.  27 

The  author's  tests  have  shown  certain  drivep  wells  to  supply 
water  containing  from  2  to  4  bacteria  per  cubic  centimeter,  while 
other  wells  have  shown  as  many  as  1,060  bacteria  per  cubic  cen- 
timeter. When  chemical  analyses  have  been  made  by  the  author 
contemporaneous  with  the  bacterial  tests,  the  higher  counts  of 
bacteria  in  driven  well  waters  are  usually  accompanied  by  evi- 
dences of  organic  matter  in  the  water. 

High  numbers  of  bacteria  in  driven  well  water  is  sometimes 
said  to  be  due  to  the  condition  of  the  casing-pipe  rather  than  to 
the  water.  But  this  scarcely  can  be  correct  ;  the  manner  of  driving 
tube  wells  and  the  condition  of  the  casing  are  quite  alike  in  all  sit- 
uations, and  counts  of  bacteria  per  cubic  centimeter  of  the  water 
as  widely  separated  as  2  to  1,400  cannot  be  satisfactorily  ac- 
counted for  by  growths  on  the  walls  of  the  pipe. 

Within  the  author's  practice  he  has  seen  no  reason  to  suspect 
any  variation  in  the  condition  of  the  interior  surfaces  of  the  iron 
casings,  while  great  variations  in  the  bacterial  counts  of  driven  well 
water  have  bean  recorded.  It  is  quite  probable,  even  with  foul 
casing-pipes,  that  the  continuous  passage  of  water  of  low  bacterial 
contents  over  the  iron  would  reduce  the  bacteria  to  the  kinds  and 
numbers  of  those  naturally  in  the  water ;  *  and  since  tests  of  the 
water  for  bacteria  are  usually  made  after  long  pumping  of  such 
wells,  it  seems  unreasonable  to  charge  high  numbers  of  bacteria 
in  water  from  tube  wells  to  the  growth  of  species  in  the  organic 
matter  supposed  to  be  on  the  interior  surface  of  the  pipes. 

Natural  nitration  through  the  materials  of  the  drift  must  de- 
pend (like  artificial  filtration  through  prepared  beds  of  sand)  upon 
several  factors,  chief  of  which  are  the  thickness  of  the  layers,  and 
size  of  the  grains  of  sand  and  gravel,  through  which  the  water  passes 
to  the  lower  levels,  where  it  is  collected  in  reservoirs  and  pockets, 
or  intercepted  by  strata  through  which  vadose  currents  are  passing. 

It  cannot  be  assumed  without  analysis  that  natural  filtration 
always  produces  pure  water.  In  some  examples  it  doubtless  does  ; 
in  others  it  may  not.  If  the  pervious  materials  of  the  drift  are 
quite  porous,  allowing  high  rates  of  vertical  percolation,  it  is  possible, 
indeed  probable,  that  such  water,  if  originally  polluted,  will  still  be 

*  Practical  Bacteriology,  Dr.  W.  Migula,  London,  1893,  pp.  151,  166. 


28  THE   PURIFICATION  OF   WATER. 

polluted  at  considerable  depths.  Beds  of  coarse  gravel  below  the 
lower  levels  of  the  ground  water  probably  have  no  influence  on  the 
quality  of  the  water  passing  through  them,  no  straining  effect  can 
be  expected,  nor  is  the  author  aware  of  any  biologic  action  taking 
place  in  deep-seated  strata  of  pervious  materials. 

Dr.  Rosenau  *  of  the  U.  S.  M.  H.  S.,  during  November  of  1895, 
made  a  very  exhaustive  examination  of  the  water  supplied  to  the 
city  of  San  Francisco,  and  found  unmistakable  evidence  of  the 
presence  of  the  colon  bacillus  and  b.  proteus  vulgatis  in  the  San 
Andreas  and  Pilarcitos  waters,  and  evidence  of  the  proteus  variety 
in  the  water  from  the  Crystal  Springs  Reservoir. 

The  Visitacion  water,  from  a  series  of  wells  130  to  180  feet 
deep  in  the  sand  and  gravel,  contained  the  colon  bacillus.  Con- 
cerning these  bacteria  Dr.  Rosenau  says  :  — 

"  The  presence  of  the  proteus  indicates  fermenting  processes,  doubtless 
the  decomposition  of  organic  matter  in  the  water.  This  organism  is  one  of  the 
most  common  and  widely  distributed  putrefactive  bacteria. 

"  The  colon  bacillus  is  an  intestinal  organism,  and  its  presence  in  the 
water  means  contamination  with  alvine  discharges,  either  of  man  or  the  lower 
animals." 

In  the  light  of  what  has  been  said  on  the  inefficiency  of  natural 
nitration  in  certain  localities,  the  discovery  of  b.  coli  communis  in 
water  from  the  wells  of  the  Visitacion  water-works  possesses  es- 
pecial significance.  The  presence  of  this  bacillus  in  water  is  an 
index  of  sewage  pollution,  either  from  man  or  animals  ;  and  the 
evidence  of  sewage  pollution  at  this  depth  (130  to  180  feet) 
clearly  demonstrates  that  natural  filtration  cannot  be  relied  upon 
in  all  localities  or  at  all  times. 

The  water  from  a  well  sunk  in  a  sand-bar  in  the  Ohio  River 
near  the  city  of  Cincinnati,  at  a  depth  of  77  feet,  contained  a 
putrefactive  bacterium  resembling  b.  proteus  vulgaris,  which  lique- 
fied 10  per  cent  gelatin  in  a  cool  cupboard  within  two  days.f  The 
water  from  the  Ohio  River  had  a  hardness  at  this  time  of  2.18 
to  2.40  parts  per  100,000  parts  of  water  ;  while  the  water  from 

*  Public  Health  Reports,  Washington,  D.C.,  April  10,  1896. 

t  Report  of  Engineer  Commission  on  Extension  and  Betterment  of  Cincinnati  Water 
Works,  189(3,  p.  23. 


SOURCES   OF  PUBLIC    WATER  SUPPLY.  29 

the  bottom  of  the  sand-bar  had  a  hardness  of  12  to  13  parts  per 
100,000  parts  of  water,  indicating  ground  water  not  well  purified 
by  percolation  through  the  pervious  materials  of  the  drift. 

It  is  fortunate,  however,  that  the  ground  water  generally  adopted 
for  public  water  supply  is  gathered  originally  on  suburban  or  unim- 
proved land,  the  runoff  of  which  at  its  worst  is  never  polluted  with 
city  sewage,  as  are  our  rivers  and  some  other  bodies  of  water ;  and 
such  water  is  infinitely  less  liable  to  contain  the  bacteria  of  disease 
communicable  by  drinking-water. 

Such  waters,  while  of  higher  purity  than  lake  and  river  waters, 
are  not  always  to  be  accepted  as  indices  of  the  efficiency  of  natu- 
ral filtration,  but  as  waters  which  never  were  seriously  polluted. 

The  distrust  of  all  natural  sources  of  water  supply,  excepting 
deep  wells,  and  springs  at  high  elevations,  by  many  of  the  European 
authorities,  has  given  a  strong  impetus  to  filtration -of  water  in 
foreign  cities.  "With  the  exception  of  mountain  springs  *  such  as 
supply  Vienna  and  Munich,  or  carefully  planned  works  for  ground 
water  such  as  supply  Dresden,  or  deep  well  water  from  the  chalk 
strata  such  as  supplies  the  Kent  district  of  London,  the  foreign 
engineers  seem  to  regard  nearly  all  other  of  the  natural  sources 
of  water  supply  as  open  to  suspicion." 

Certain  standards  of  quality  in  articles  of  diet  are  recognized 
the  world  over,  and  even  the  poorer  grades  of  food  materials  are 
required  by  law  to  be  of  a  quality  that  will  cause  no  injury  to 
health.  All  civilized  nations  insist  upon  absolute  immunity  from 
disease  through  articles  of  diet ;  and  why  should  people  be  less 
concerned  about  the  quality  of  their  domestic  water  supplies  than 
they  are  about  the  quality  of  articles  of  food  ?  No  other  sub- 
stance enters  so  largely  into  the  support  of  the  animal  system  ; 
and  the  same  care  and  safeguards  which  are  applied  to  the  ordi- 
nary articles  of  food  should  be  applied  to  drinking-water,  and  water 
for  most  of  the  domestic  uses. 

The  objection  to  polluted  water  is  not  so  much  to  the  organic 
matter  which  it  may  contain,  as  it  is  to  the  possibility  of  the  pres- 
ence of  some  of  the  bacteria  concerned  in  the  production  of  disease. 

*  The  Water  Supplies  of  Eight  Cities  in  Relation  to  Typhoid  Fever  Rates,  by  the  author, 
Chicago,  1896. 


30  THE   PURIFICATION  OF   WATER. 

At  the  present  time  some  23  of  the  pathogenic  organisms  have 
been  found  in  water  or  sewage,  among  which  are  the  germs  of 
typhoid  fever  and  cholera. 

The  latter  being  a  disease  not  indigenous  to  this  country,  and 
rarely  coming  even  by  importation,  it  is  sufficient  to  consider  the 
typhoid  bacillus  as  the  special  object  to  be  avoided  in  selecting 
sources  of  water  supply,  or  to  be  restrained  by  methods  of  purifi- 
cation of  polluted  waters. 

While  other  pathogenic  organisms  may  be  imbibed  through 
drinking-water,  or  be  taken  into  the  system  through  some  other 
form  of  contact  with  water,  and  set  up  processes  which  lead  to 
disease,  the  proof  of  this  is  still  lacking  ;  and  the  distinguishing 
purpose  of  pure  or  purified  water  is  the  reduction  of  the  typhoid 
fever  rates.  Moreover,  the  use  of  a  naturally  pure  water,  and  the 
processes  resorted  to  for  the  purification  of  polluted  waters,  will 
probably  have  the  same  influence  on  all  other  water-borne  patho- 
genic organisms  as  on  the  typhoid  bacillus ;  and  remedies  which 
will  be  successful  in  excluding  this  one  germ  from  our  domestic 
waters  will  (so  far  as  we  now  know)  operate  with  equal  force 
against  all  other  water-carried  disease  germs. 

Before  discussing  the  probability  of  typhoid  fever  infection  by 
public  water  supplies,  it  may  be  well  to  remark  that  other  dis- 
orders of  the  animal  system  may  be  traced  to  certain  inorganic 
matters  in  water.  Thus  waters  high  in  lime  or  other  bases  are 
not  the  best  for  continuous  use  as  a  drinking-water.  Certain  of 
these  minerals  may,  in  very  limited  quantities  and  at  times,  be  of 
advantage  to  the  animal  system  ;  but  the  continuous  use  of  a  water 
high  in  mineral  contents  is  recommended  by  physicians  only  in 
special  cases,  and  to  correct  certain  disorders  or  symptoms  to 
which  such  waters,  or  rather  their  mineral  contents,  are  fitted. 

In  early  life  that  part  of  the  human  system  which  is  intended 
to  eliminate  the  excess  of  salts  in  water  and  food  is  very  powerful, 
and  capable  of  a  large  amount  of  daily  work  without  injury.  As 
we  grow  older,  and  especially  in  advanced  life,  this  part  of  the 
system  can  be  easily  overworked  ;  and  when  it  is,  the  blood  will 
contain  an  abnormal  amount  of  these  salts  or  their  acid  products 
which  lead  to  very  serious  results.  The  excess  of  salts  often  is 


SOURCES   OF  PUBLIC    WATER  SUPPLY,  81 

deposited  in  the  capillaries  and  other  blood  vessels  where  the  cir- 
culation is  sluggish,  rendering  them  brittle  and  easy  of  rupture  bv 
shocks  or  vascular  pressure. 

Embolisms,  apoplexy,  and  paralysis  may  be  traced  to  this  de- 
posit of  lime  or  some  other  base  (in  excess  in  the  blood),  which 
impedes  the  movement  of  the  fluid  through  the  vascular  system, 
and  produces  stresses  in  some  of  the  more  delicate  vessels  or  cap- 
illaries, which  they  are  unable  to  resist.  This  objection  to  what 
are  usually  termed  hard  waters  for  drinking-purposes  may  be  very 
refined,  and  too  remote  for  practical  consideration  in  the  light  of 
the  more  pronounced  objection  to  the  sewage  pollution  of  waters ; 
but  it  is  worthy  of  thought,  and  continued  study  of  this  aspect 
of  drinking-waters  may  verify  the  author's  opinion,  that  a  soft, 
pure  drinking-water  is  better  for  the  human  system  than  a  hard, 
pure  drinking-water. 

While  there  is  a  popular  sentiment  against  the  use  of  a  water 
known  to  be  sewage  polluted,  this  is  neither  as  strong  nor  as  well 
grounded  as  it  must  be  to  secure  reforms  in  the  water  supplies  of 
many  of  our  cities.  When  people  come  to  understand  that  disease 
and  death  lurk  in  sewage-polluted  waters,  and  that  to  drink  such 
waters,  or  permit  others  to  drink  them,  is  an  invitation  to  suffering 
and  -loss  of  life,  then  communities  will  demand  remedies  for  the 
evils  which  in  many  instances  are  now  but  vaguely  supposed  to 
exist. 

There  are  several  well  recognized  tests  of  the  quality  of  a  water 
supply :  — 

First,  the  test  by  chemical  methods,  which  measures  the 
amounts  of  nitrogenous  organic  matter  in  water  as  ammonias,  the 
chlorides  of  sodium  and  potassium  as  chlorine,  the  reduction  of 
nitrogenous  matters  to  nitric  and  nitrous  acids,  as  nitrates  and 
nitrites,  and  finally  determines  the  presence  of  minerals,  as  arsenic, 
copper,  etc.,  which  may  be  in  quantity  sufficient  to  make  a  given 
water  supply  dangerous  to  health.  Chemistry  divides  up  the  dis- 
solved and  suspended  matters,  and  indicates  the  nature  and  amount 
of  each. 

Second,  the  test  by  biological  methods,  which  deals  exclu- 
sively with  the  number  and  kinds  of  organisms  present,  and  their 


32  THE   PURIFICATION  OF    WATER. 

probable  origin  in  the  water,  and  more  directly  and  certainly 
than  chemistry  determines  the  fitness  of  water  for  domestic 
uses. 

Finally,  the  quality  of  a  given  water  supply  may  be  roughly 
but  effectually  determined  by  allowing  the  people  to  use  it,  and 
noting  its  influence  on  their  health.  This  method  prevails  in 
nearly  all  the  cities  of  this  country ;  and  a  comparison  of  the 
typhoid  fever  rates  from  these  with  the  rates  of  other  cities  where 
the  quality  of  water  supply  is  the  subject  of  careful  and  constant 
supervision,  clearly  demonstrates  the  importance  to  every  com- 
munity of  the  best  water  which  skill  and  money  can  provide. 

For  many  years  the  cities  of  Jersey  City  and  Newark,  N.J., 
drew  their  water  supplies  from  the  Passaic  River  at  Belleville. 
Above  this  point,  as  early  as  1894,  the  river  was  receiving  the 
sewage  from  two  hundred  thousand  people  ;  and,  being  subject  to 
tidal  influence,  some  of  this  sewage  was  carried  up  and  down  past 
the  two  water-works  intakes,  until  it  went  with  ebb-tides  into 
Newark  Bay,  or  was  deposited  by  subsidence  on  the  bottom  of  the 
river.  At  the  time  of  the  author's  examination  of  the  Jersey  City 
water  (August,  18&4),  some  destruction  of  the  sewage  by  the 
action  of  the  bacteria,  infusoria,  and  other  living  organisms,  in  the 
water  evidently  was  going  on,  but  at  a  rate  too  slow  to  have  any 
marked  effect  on  its  quality.  In  April  of  1892  Newark  abandoned 
the  Passaic  River,  and  commenced  to  draw  its  water  supply  from 
impounding  reservoirs  in  the  valley  of  the  Pequannock  River,  while 
Jersey  City  continued  to  take  all  or  part  of  its  water  from  the  Pas- 
saic River  until  November,  1896. 

«  These  two  cities  are  separated  principally  by  a  large  meadow  or  swamp.* 
They  are  embraced  in  the  same  "system  of  electric  street  railroads,  subject  to 
the  same  climatic  conditions,  and,  excepting  their  sources  of  public  water  sup- 
ply, there  is  no  known  reason  why  any  marked  difference  in  the  typhoid  fever 
rates  should  exist  between  them." 

"  A  comparison  of  the  typhoid  rates  for  the  past  seven  years  from  these 
two  cities,  however,  furnishes  important  evidence  that  water  is  the  carrier  of 
the  typhoid  bacillus,  and  that  the  typhoid  death  rate  bears  a  just  relation  to 
the  sewage  pollution  of  our  sources  of  public  water  supply." 

*  Engineering  Record,  March  23,  1895.     (Including  rates  for  1895-1896.) 


SOURCES   OF  PUBLIC    WATER  SUPPLY. 


33 


In  the  following  table  are  given  the  death  rates  from  typhoid 
fever  per  100,000  of  population  living  :  — 


YEAR, 

Death  Rate, 


YEAR, 

Death  Rate, 

Until  1892,  and 
for  nearly  four  months 
of  that  year,  both  cities 
drew  their  water  sup- 
plies from  the  Passaic 
River,  at  Belleville. 
During  April  of  1892, 
the  supply  of  Newark 
was  changed  to  the 
Pequannock  source ; 
while  Jersey  City  con- 
tinued the  use  of  Pas- 
saic water  until  No- 
vember of  1896,  when 
the  whole  supply  of 
that  city  also  was 
obtained  from  the 
Pequannock  River. 
While  the  influence 
of  the  Pequannock 
water  is  not  so  well 
shown  in  the  annual 
records  of  Jersey  City, 
a  study  of  the  monthly 
typhoid  mortality  for 
1896  reveals  the  re- 
markable vileness  of 
the  water  from  the 
old  source. 


JERSEY   CITY,  N.  J. 
1890.       1891.       1892.       1893.       1894. 

91        95        53        60        76 


NEWARK,  N.  J. 
1890.       1891.        1892. 

60       81        45 


1893. 

28 


15 


1895.       1896. 
71       61-62 


1895.       1896. 

17        21 


34 


THE  PURIFICATION  OF   WATER. 


Considering  that  the  average  death  rate  from  typhoid  fever  in 
Newark  since  the  introduction  of  the  Fequannock  water  is  still 
from  two  and  a  half  to  five  times  what  it  would  be  if  supplied 
with  water  like  that  of  some  of  the  larger  cities  of  Europe,  one 
can  understand  how  objectionable  must  be  the  Passaic  River  as  a 
source  of  dietetic  water  supply. 

The  average  rate  for  Newark  for  1890  and  1891  was  70.5  ; 
while  the  average  rate  for  1892  to  1896  inclusive  was  25.2,  or  a 
reduction  of  64.3  per  cent.  The  average  rate  for  Jersey  City  for 
1890  and  1891  was  93  ;  and  the  average  rate  for  1892  to  1896 
inclusive  was  64. 3^  a  reduction  of  30  per  cent. 

This  reduction  in  the  case  of  Jersey  City  is  due  to  other  causes 
than  the  use  of  Pequannock  water ;  and  allowing  for  the  same 
general  influences  in  the  city  of  Newark,  the  net  reduction  in  the 
typhoid  fever  rates  by  Pequannock  water  was  34.3  per  cent. 

The  distinct  influence  of  the  Pequannock  water  when  used  in 
Jersey  City  in  comparison  with  Passaic  water,  is  shown  by  the 
following  table  :  — 

JERSEY   CITY,  N.  J.  (1896).     POPULATION,  187,OO8. 


MONTH. 

PUMPED  FROM 
PASSAIC  RIVER. 
Av.  DAILY  GALS. 

BY  GRAVITY  FROM 
PEQUANNOCK  RIVER. 
Av.  DAILY  GALS. 

PERCENTAGE 
OF  PEQUAN- 
NOCK WATER. 

DEATHS  FROM 
TYPHOID 
FEVER. 

January, 

18,100,000 

6,600,000 

27 

28 

February, 

15,700,000 

10,400,000 

40 

30 

March, 

14,700,000 

11,500,000 

44 

16 

April, 

9,800,000 

13,900,000 

59 

9 

May, 

13,200,000 

13,000,000 

50 

6 

June, 

6,300,000 

21,000,000 

76 

7 

July, 

5,700,000 

22,400,000 

80 

3 

August, 

6,900,000 

22,100,000 

76 

3 

September, 

7,900,000 

19,900,000 

72 

3 

October, 

3,500,000 

22,500,000 

86 

4 

November, 

.  .  . 

25,500,000 

100 

1 

December, 

.  .  . 

28,400,000 

100 

5 

Of  the  115  deaths  from  typhoid  for  the  year  (1896),  74  oc- 
curred during  the  first  three  months,  for  which  time  the  average 
proportion  of  Pequannock  water  was  39  per  cent. 

On  comparing  January  and  February,  when  67  per  cent  of  the 


SOURCES   OF  PUBLIC    WATER   SUPPLY. 


35 


water  supply  was  drawn  from  the  Passaic  River,  with  the  months 
of  November  and  December,  when  all .  the  water  was  from  the 
Pequannock  River,  the  reduction  in  the  typhoid  rates  was  nearly 
90  per  cent. 

From  the  following  table  it  appears  that  the  typhoid  death  rate 
is  generally  higher  in  Jersey  City  for  the  months  of  October, 
November,  and  December,  than  for  the  months  of  January,  Febru- 
ary, and  March,  as  it  usually  is  for  other  cities  ;  and  assuming  this 
to  be  true  for  the  year  1896,  then  with  an  increased  or  complete 
substitution  of  Pequannock  water  for  the  sewage  polluted  Passaic 
water,  there  was  a  reduction  of  over  86  per  cent  in  the  typhoid 
death  rates. 

DEATHS    FROM    TYPHOID   FEVER,  JERSEY    CITY,  N.  J. 


YEAR, 

1893. 

1894. 

1895. 

189G. 

1897. 

POPULATION, 

175,000. 

179,939. 

184,173. 

187,098. 

190,000? 

January, 

12 

16 

12 

28 

1 

February, 

3 

5 

9 

30 

6 

March, 

15 

1 

20 

16 

2 

April, 

7 

6 

19 

9 

2 

May, 

2 

3 

9 

6 

2 

June, 

11 

4 

7 

7 

3 

July, 

6 

10 

7 

3 

1 

August, 

13 

14 

11 

3 

2 

September, 

8 

16 

6 

o 
«J 

2 

October, 

9 

23 

13 

4 

3 

November, 

11 

7 

9 

1 

•  • 

December, 

8 

14 

14 

5 

The  average  deaths  from  typhoid  for  the  months  of  November 
and  December  for  the  years  1893  to  1895  inclusive,  during  which 
time  Passaic  water  alone  was  used  (corrected  for  population  of 
1896),  were  22,  compared  with  which  months  the  deaths  for  1896, 
using  Pequannock  water  alone,  were  6,  or  the  reduction  was  73 
per  cent.  Comparing  the  deaths  for  January  and  February,  1893 
to  1896  inclusive,  with  the  deaths  for  the  same  months  of  1897, 
the  reduction  of  the  death  rate  was  over  76  per  cent,  by  reason  of 
the  complete  substitution  of  Pequannock  for  Passaic  water.  The 
water  from  the  Pequannock  was  first  turned  into  the  Jersey  City 
mains  Jan.  10,  1896. 


36  THE   PURIFICATION  OF   WATER. 

The  city  of  Lawrence,  Mass.,  with  a  population  (1896)  of 
55,000,  draws  its  water  supply  from  the  Merrimac  River,  after  it 
has  received  the  sewage  from  Lowell,  nine  miles  above.  The  city 
of  Lowell,  with  a  population  (1896)  of  85,700,  draws  its  water 
supply  partly  from  the  Merrimac  River,  and  partly  from  a  system 
of  driven  wells.  Lawrence,  however,  has  filtered  its  water  since 
September  of  1893,  while  Lowell  uses  such  water  as  is  drawn 
from  the  river  in  its  natural  state. 

The  typhoid  fever  death  rates  per  100,000  of  population  living, 
for  these  two  cities,  since  1890,  are  shown  in  the  following  table  :  — 

YEAR,        1890.     1891.     1892.      1893.     1894.      1895.     1896. 

Lowell,  158  98  90  61  55  39  42 

Lawrence,       123          115          102  93  48  31  15 

The  average  death  rates  for  the  years  1890  to  1892  inclusive, 
before  filtered  water  was  used  in  Lawrence,  were  for  Lowell  115, 
and  for  Lawrence  113,  or  quite  the  same ;  while  for  the  three 
years,  1894  to  1896  inclusive,  during  which  time  filtered  water  was 
used  in  Lawrence,  the  average  rates  were  for  Lowell  45,  and  for 
Lawrence  31.  The  percentage  of  reduction  in  the  rates  for  Lowell 
was  40,  and  for  Lawrence  over  72,  leaving  a  net  reduction  of  32 
per  cent  to  be  credited  to  the  filtered  water  of  the  latter  city. 

This  is  not  all  that  the  filtered  water  is  entitled  to,  according 
to  reports  from  Lawrence,  which  show  that  many  of  the  mill  opera- 
tives continue  to  use  canal  water,  which  is  unfiltered  Merrimac 
water,  in  defiance  of  the  notices  posted  conspicuously  in  the  mills 
that  canal  water  is  dangerous  to  health,  and  should  not  be  drunk  ; 
and  a  fairer  comparison  will  be  of  the  years  1890  to  1892  inclusive, 
before  the  filtered  water  was  introduced,  with  1896,  when  the  use 
of  filtered  water  was  doubtless  more  general  than  for  1893,  1894, 
and  1895.  Upon  this  comparison,  Lowell  shows  a  reduction  of 
63.5  per  cent  on  the  former  rates,  while  Lawrence  shows  a  reduc- 
tion of  nearly  87  per  cent  on  the  former  rates,  or  a  net  reduction 
in  favor  of  the  filtered  water  of  Lawrence  of  over  23  per  cent. 

An  examination  of  the  table  indicates  that  some  influences 
were  at  work  in  Lowell  since  the  filtered  water  was  introduced  in 
Lawrence,  which  very  materially  reduced  the  typhoid  fever  rates 


SOURCES   OF  PUBLIC    WATER  SUPPLY.  37 

of  the  former  city ;  *  but  whatever  these  influences,  they  were  not 
so  efficient  in  reducing  the  death  rates  as  were  those  of  the  filtered 
water  supplied  to  Lawrence. 

Standing  alone,  the  nitration  of  the  polluted  Merrimac  River 
water  has  reduced  the  typhoid  rates  for  Lawrence  nearly  ninety 
per  cent ;  and  by  the  correction  of  certain  errors  in  the  design  of 
this  filter,  with  total  abstinence  of  the  people  from  unfiltered 
water,  a  greater  reduction  than  this  is  to  be  expected. 

The  great  difficulty  in  the  way  of  advancing  practical  works 
of  water  purification  is  the  lack  of  proof  that  water  is  really  the 
cause  of  disease.  A  moment's  reflection  will  convince  one  that 
apart  from  transmission  by  personal  contact,  as  in  smallpox,  or  by 
food,  as  milk,  etc.,  all  infectious  diseases  must  be  transmitted  to 
human  beings  from  the  air,  the  soil,  or  from  water.  The  evidence 
now  that  certain  diseases  like  tuberculosis  and  diphtheria  are  due 
to  air-borne  germs  is  very  satisfactory.  Similarly  from  the  soil 
we  obtain  the  germs  of  tetanus  and  anthrax,  and  the  evidence  is 
very  convincing  to  the  majority  of  investigators  that  typhoid 
fever  and  cholera  are  almost  exclusively  water-carried  diseases. 

Dr.  Edmund  Rogers,  an  eminent  physician  of  Denver,  Col., 
classes  mountain  fever  with  typhoid  fever.  Both  are  continuous 
fevers,  and  arise  from  similar  causes.  If  the  fever  is  light,  it  is 
called  mountain  fever ;  if  it  becomes  intense,  it  is  called  typhoid. 
Typhoid  seems  to  be  endemic  in  parts  of  certain  States  where 
mountain  water  constitutes  the  supply  for  potable  purposes.  It  is 
a  mistake  to  assume  that  mountain  water  must  be  pure  water, 
where  exposed,  as  it  is  in  many  localities,  to  the  sewage  from 
mining-camps  or  other  permanent  or  migratory  settlements  upon 
the  watershed  above  the  points  at  which  such  water  is  taken  for 
domestic  supply.  Small  centers  of  typhoid  are  found  upon  the 
mountain  slopes  at  all  times,  and  these  may  furnish  material  for 
the  infection  of  cities  dependent  upon  mountain  water. 

*  After  above  paragraph  was  written,  a  communication  to  the  author  from  Mr.  R.  J. 
Thomas,  superintendent  of  the  Lowell  water-works,  contained  the  information  that  since 
February,  1896,  "  No  water  has  been  taken  from  the  river,  direct  nor  through  the  filter  [described 
in  Chapter  XI.],  a  sufficient  supply  of  very  good  water  having  been  obtained  from  a  system  of 
driven  wells." 


38  THE  PURIFICATION  OF   WATER. 

A  foot-note  in  Mr.  Preller's  paper  on  the  water-works  of  Zurich, 
Switzerland,  contains  the  following  statement :  — 

"  Spring  water  rising  in  the  upper  Alpine  reaches  is,  in  spite  of  its  crystal- 
line clearness,  peculiarly  liable  to  pollution  by  the  scattered  droppings  of  graz- 
ing cattle,  unless  the  whole  drainage  area  is  inclosed.  Although  the  water 
purifies  itself  to  a  great  extent  in  the  course  of  its  flow,  it  can  produce  epi- 
demics by  the  droppings  of  diseased  cattle,  of  which  cases  are  recorded  in 
the  upper  Rhine  Valley,  at  Neuchatel,  and  at  Appenzell." 

Here  is  a  danger  to  which  too  little  attention  has  been  given. 
In  considering  the  population  of  a  given  watershed  no  mention 
(within  the  author's  knowledge)  has  ever  been  made  of  the  num- 
ber of  domestic  animals,  while  careful  enumeration  is  given  of  the 
people  per  square  mile.  Domestic  animals  are  not  always  in  a 
state  of  health  ;  and  evidently  any  disease  germs  which  may  be  in 
the  excreta  of  these  scattered  over  a  given  watershed  will  be 
washed  into  the  streams,  lakes,  or  reservoirs  with  each  succeeding 
storm. 

It  is  not  likely  that  any  farmer  would  fancy  having  the  sewage 
from  his  stock  discharged  into  his  domestic  well,  yet  the  same 
thing  really  occurs  when  the  runoff  of  rainfall  on  perhaps  every 
watershed  carries  this  same  sewage  from  domestic  animals  into 
our  sources  of  potable  water  supply. 

Some  of  the  diseases  of  cattle  and  sheep,  for  instance,  are  rec- 
ognized as  diseases  of  man  ;  and  while  no  evidence  exists  that  these 
are  infectious  by  water  carriage,  still  it  is  certainly  very  imprudent 
to  assume  that  no  danger  can  exist  in  this  direction  simply  be- 
cause it  has  not  been  proven. 

It  is  sometimes  held  that  all  typhoid  fever  cannot  be  charged 
to  impure  water  supplies  :  this  may  or  may  not  be  true ;  but  in 
any  family  the  only  things  that  are  common  to  all  its  members 
are  the  water,  the  soil,  and  the  air  surrounding  the  premises  — 
all  other  possible  causes  of  disease  infection  are  affected  by  the 
personal  habits  of  the  members.  Nearly  all  articles  of  diet,  ex- 
cepting water  and  milk  (as  a  beverage),  are  sterilized  by  cooking 
and  baking  before  they  are  ingested ;  and  such  articles  as  are  not 
sterilized  are  usually  washed  with  water  before  they  are  brought 
to  the  table. 


SOURCES   OF  PUBLIC    WATER  SUPPLY.  39 

Other  causes  than  domestic  water  supplies  liave  been  shown 
to  be  responsible  for  typhoid  epidemics,  but  water  only  has  been 
shown  to  be  the  cause  of  our  high  continuous  typhoid  fever  rates. 

The  investigation  of  epidemics  of  typhoid  fever  in  isolated 
localities  has  suggested  that  in  many  of  these  the  cause  must 
have  been  local ;  and  it  has  been  held  that  when  no  known  pol- 
lution of  the  water  supply  by  domestic  sewage  has  occurred,  the 
water  supply  was  blameless. 

A  little  thought  upon  the  subject  suggests  that,  in  settlements 
far  removed  from  the  ordinary  channels  of  typhoid  infection,  the 
same  causes  may  be  at  work  that  we  find  in  more  populous  centers. 

The  colon  bacillus  may  be  found  in  any  water  open  to  pollu- 
tion from  the  excremental  refuse  of  domestic  animals  ;  and  may  it 
not  be  possible  that  the  colon  bacillus  from  a  sheep  or  hog,  when 
taken  into  the  human  system,  becomes  the  active  cause  of  typhoid 
fever  ?  and  if  it  does,  is  it  not  easy  to  understand  how  epidemics 
can  arise,  even  when  no  apparent  cause  may  exist  ?  It  is  not 
known  to  the  author  that  any  one  excepting  Professor  Lankester 
believes  that  the  colon  bacillus  may  become  the  typhoid  bacillus  ; 
and  no  one  but  Harvey,  two  hundred  and  fifty  years  ago,  believed 
in  the  circulation  of  the  blood.  Harvey,  however,  was  right,  while 
the  others  were  wrong ;  and  Lankester  may  be  right  to-day.  Many 
steps  must  be  taken  to  prove  his  views  ;  and  if  proven  by  time, 
the  cause  of  these  isolated  typhoid  cases  will  be  made  very  clear, 
and  water  again  will  be  shown  to  be  the  carrier  of  the  infection. 

The  fact  has  been  repeatedly  shown,  that  certain  so-called 
pathogenic  organisms  have  their  virulence  exalted  by  contact  with 
certain  other  so-called  non-pathogenic  organisms  ;  and  the  com- 
bined effect  of  the  action  of  the  colon  bacillus  normal  to  the 
human  intestine  and  the  colon  bacillus  from  domestic  animals 
may  be  the  symptoms  and  lesions  characteristic  of  typhoid  fever. 

Proof  of  this  is  lacking,  but  certain  epidemics  seem  to  be 
accountable  for  in  no  other  way. 


40  THE   PURIFICATION  OF   WATER. 


CHAPTER    III. 

BACTERIAL    CONTENTS    OF   VARIOUS    WATERS. 

THE  great  variation  in  the  numbers  of  bacteria  counted  from 
the  same  source  on  different  dates  of  the  same  month,  or  upon  a 
series  of  plates  all  inoculated  in  the  same  manner  at  the  same 
time,  has  frequently  been  noted,  and  is  probably  due  primarily  to 
the  lack  of  uniformity  in  the  distribution  of  the  bacteria  through- 
out the  water  sample,  and  somewhat  to  the  nutrient  properties  of 
the  media  employed,  and  temperature  of  growth. 

When  the  nutrient  media  are  from  the  same  solution  for  a 
series  of  three  or  more  plates,  and  the  conditions  in  other  respects 
the  same,  the  author  has  frequently  found  a  great  difference  in 
the  number  of  bacteria  from  successive  drops  of  water  from  the 
same  sample,  which  can  be  reconciled  only  upon  the  theory  of  a 
lack  of  uniform  distribution  of  the  organisms  in  the  water  sample. 
It  is  well  known,  in  the  case  of  a  water  sample  allowed  to  stand 
for  a  few  minutes,  that  the  number  of  organisms  varies  consider- 
ably with  the  depth  at  which  they  are  taken  by  the  dropping  tube, 
the  smaller  number  being  found  near  the  surface  of  the  water, 
and  the  larger  number  at  the  bottom.  To  avoid  an  error  due  to 
depth  of  water  when  the  sample  is  taken  up  for  inoculation  of 
the  nutrient  media,  it  is  customary  to  shake  the  bottle  thoroughly 
before  it  is  opened  and  the  sample  taken,  to  distribute  as  well  as 
possible  the  organisms  throughout  the  whole  volume  of  water. 

The  number  of  bacteria  per  cubic  centimeter  of  a  water  sam- 
ple also  depends  upon  how  the  inoculation  is  made ;  whether  the 
water  is  taken  from  the  collecting  bottle  and  quickly  dropped  into 
the  gelatin,  or  is  given  time  to  permit  of  the  bacteria  settling 
to  the  point  of  the  pipette  before  inoculating  the  tube.  A  test  for 
the  effect  of  gravitation  of  the  bacteria  after  the  sample  of  water 
has  been  taken  up  in  the  dropping  tube  is  given  below :  — 


BACTERIAL    CONTENTS  OF   VARIOUS    WATERS. 


41 


PLATE  I.  —  Water  taken  from  the  beaker  into  the  tube,  and  a  few  minutes 
allowed  for  the  bacteria  to  settle  to  the  point  of  the  tube  before  the  inocula- 
tion was  made. 

PLATE  II.  —  Inoculation  quickly  made  after  the  sample  of  water  was 
taken  into  the  dropping  tube. 

PLATE  III.  —  Same  as  PLATE  II. 

WATER   FROM   DOMESTIC   CISTERN. 

PLATE       I.  —  Bacteria  per  cubic  centimeter,     1,330 
PLATE     II.—          «         "         «  «  460 

PLATE  III.—         "        «         "  «  480 

Tests  of  Ohio  River  water  as  it  comes  through  the  taps  of  Cin- 
cinnati have  been  made  by  the  author  with  the  following  results  : 

BACTERIAL   CONTENTS   OF   OHIO    RIVER   WATER   AS   SUPPLIED   TO   THE 
CITY   OF   CINCINNATI. 


DATE. 

DAYS  OF  GROWTH. 

COLONIES  PER  C.  C.  OF  WATER. 

July  18,  1894, 

4    on  gelatin, 

7,665-    9,570 

"     24,      " 

5     " 

94,050-163,000 

Aug.     1,      " 

7     " 

1,680 

Oct.     4,      " 

4     "  agar, 

9,856 

"      15,      " 

5     "    .   " 

1,872 

"      15,      " 

5     "  gelatin, 

5,820 

"     29,      " 

5     « 

1,760 

Nov.     7,      " 

5     "        " 

2,674 

Mar.   13,  1895, 

6     "        " 

20,724 

July    23,      " 

4     "        " 

2,835-    2,910 

Aug.  30,      " 

4          •  i                 it 

561 

Nov.  29,      " 

4         tt               it 

8,448-    9,120 

Dec.    12,      " 

5     tt        n 

2,455-    3,295 

Jan.     15,  1896, 

n  "    u 

3,146-    4,825 

"     22,      " 

5     » 

1,248-     1,704 

"      27,      " 

4     " 

1,498-     1,701 

Feb.      1,      " 

4     " 

5,025-    5,100 

"         9,      " 

4|  "        « 

1,596-     1,717 

"       10,      " 

6     "        " 

2,030-    2,155 

"       16,      " 

71  ,.        „ 

1,442-     1,680 

"       16,      " 

41  „        « 

1,458-    1,593 

Mar.      1,      "" 

3f  " 

842-     1,446 

"        2,      " 

5     " 

1,051-     1,821 

Apr.    12,      " 

5*  «        » 

1,657-     1,883 

June   29,      " 

4     .< 

2,304-    2,832 

July      4,      " 

4     « 

495-        644 

Dec.    11,      " 

4     " 

10,742-  11,300 

"      13,      " 

4     .* 

6,333-     9,637 

42  THE    PURIFICATION  OF   WATER. 

There  is  nothing  unusual  about  the  bacterial  contents  of  the 
Ohio  River  water.  All  rivers  receiving  sewage,  or  the  wash  of 
soil,  contain  relatively  large  numbers  of  bacteria,  most  of  which 
are  the  common  water  species,  and  concerned  in  the  breaking  up 
of  organic  matter.  The  water  supply  of  Cincinnati  is  subjected 
to  no  kind  of  purification  before  it  is  delivered  to  the  consumers, 
and  any  objection  which  may  exist  to  it  before  it  is  pumped  from 
the  river  still  exists  when  it  reaches  the  consumer.  Cincinnati  is 
one  of  the  cities  of  this  country  which  has  a  high  typhoid  fever 
rate.- 

According  to  Mr.  M.  N.  Baker,*  who  has  given  very  serious 
consideration  to  the  subject  of  sewage  disposal  and  water  purifica- 
tion, "  When  sewage-polluted  water  must  be  used,  means  should 
be  adopted  for  its  purification." 

With  large  dilution  of  sewage  containing  pathogenic  organisms, 
the  chance  of  taking  any  of  these  into  the  stomach  through  the 
medium  of  drinking-water  is  diminished,  but  the  longevity  of  the 
organisms  is  increased.  In  an  undiluted  sewage  the  typhoid  bacil- 
lus would  probably  perish  within  a  short  time.  In  pure  water, 
that  is,  water  free  from  the  energetic  putrefactive  organisms,  the 
typhoid  bacillus  would  live  for  weeks.  If  other  organisms  be 
absent  from  the  water,  i.e.,  if  the  water  is  sterile,  the  typhoid 
bacillus  has  been  known  to  survive  for  three  months. f 

Dr.  Abbott  states  that  no  bacteria  are  found  in  deep  well 
water,J  but  the  author's  experience  has  been  quite  to  the  con- 
trary ;  no  well  water,  however  deep  the  well,  has  failed  to  contain 
some  bacteria,  and  some  moderately  deep  driven  wells  have  shown 
considerable  numbers  upon  bacterial  test. 

The  examinations  by  Professor  Sedgwick,  and  the  table  of 
results  by  the  author  which  are  given  on  pp.  44  and  45,  throw 
some  light  on  the  bacterial  contents  of  well  water. 

Certain  experiments  have  been  made  to  determine  the  effect  of 
domestic  filters  on  Ohio  River  water.  These  filters  are  all  sold  as 
germ-proof  apparatus,  and  the  purchaser  in  most  instances  really 

*  New  Jersey  Sanitary  Association,  Proceedings,  1895,  p.  75. 

t    Water  Supply  for  Cities,  by  author,  University  of  Illinois,  1896.  p.  12. 

\  Principles  of  Bacteriology,  by  A.  C.  Abbott,  M.D.,  Philadelphia,  1894,  pp.  419-436. 


BACTERIAL    CONTENTS  OF   VARIOUS    WATERS.  43 

believes  in  their  efficiency  in  the  prevention  of  th'e  passage  of  bac- 
teria. The  best  domestic  filter  is  the  Pasteur,  with  which  at  this 
time  nearly  every  person  is  familiar ;  but  even  this  will  not  restrain 
the  passage  of  bacteria  for  any  length  of  time.  Variations  in  the 
porosity  of  the  porcelain  tubes  will  increase  or  diminish  the  rate 
of  delivery  of  water  through  the  unglazed  material,  and  correspond- 
ingly affect  the  rapidity  with  which  certain  of  the  bacteria  will 
grow  through  the  pores  of  the  tubes. 

BACTERIAL  CONTENTS  OF  WATER. 

PASTEUR-CHAMBERLAND  FILTERS,  — 

DAYS  OF  GROWTH  COLONIES  PER  C.  C. 

DATE-  ON  GELATIN.  OF  WATER. 

1.  June  16,  1894,  7  62 

Tube  sterilized  just  before  use. 

2.  Oct.  10,  1894,  5  580-974-1,536 

This  filter  in  restaurant,  and  probably  not  well  attended  to. 

3.  Oct.  10,  1894,  5  2 

This  is  a  new  filter  with  freshly  sterilized  tubes. 

4.  Oct.  15,  1894,  10  4 

Sample  from  new  filter. 

5.  Oct.  24,  1894,  5  180-209-436 

This  filter  is  in  a  popular  hotel,  and  carefully  attended  to. 

6.  Nov.  25,  1894,  19  4-8 

This  filter  in  drug-store,  water  used  for  prescription  purposes. 

7.  May  23,  1895,  7  201-236-287 

Same  as  No.  6,  water  still  used  for  prescription  purposes. 

8.  May  23,  1895,  7  167-182-293 

Same  as  No.  2,  tubes  renewed. 

Freudenrich  *  has  made  some  experiments  with  the  Pasteur 
filter  to  determine  the  sterility  of  the  filtrate  at  different  dates 
after  sterilization  of  the  tubes,  and  for  different  temperatures  of 
the  room  in  which  the  filters  were  kept,  and  finds  that  at  a  tem- 
perature of  35°  C.  the  filter  delivered  sterile  water  at  the  end  of 
six  days,  while  at  a  temperature  of  22°  C.  the  filtrate  in  some  cases 
was,  and  in  others  was  not,  sterile  at  the  end  of  ten  days.  The 
cause  of  one  filter  furnishing  sterile  water,  and  another  operating 
under  the  same  conditions  giving  a  filtrate  containing  bacteria,  is 

*  Centralblatt  fur  Barter  iologie,  vol.  xii.,  1892,  p.  240. 


44 


THE  PURIFICATION  OF   WATER. 


explained  by  the  investigator  as  being  due  to  the  difference  m  the 
density  or  porosity  of  the  tubes,  and  to  differences  in  the  micro- 
organisms in  the  water  at  different  times. 

It  has  been  the  author's  experience  with  water  from  niters  of 
this  type  that  they  never  furnish  absolutely  sterile  water  ;  for  upon 
a  series  of  plates  inoculated  with  such  water,  while  some  may  re- 

BACTERIAL   CONTENTS   OF   WELL   WATER,  EASTERN  MASSACHUSETTS. 
(From  Examinations  by  PROFESSOR  W.  T.  SEDGWICK.  *) 


LOCATION  OF  WELL. 

DEPTH  IN 
FEET. 

COLONIES  PER  C.  C.  OF 
WATER. 

Cambridge, 

103 

254-    269 

« 

100 

30 

« 

454 

206-    214 

« 

254 

135-    150 

Lowell, 

.  . 

228 

<( 

.  . 

178(Gly.Agar.) 

Cambridgeport  , 

198 

116 

<« 

198 

192-    193 

(C 

198 

258-    262 

Boston, 

213 

138-    139 

« 

213 

130-    140 

<( 

213 

101-    106 

« 

377 

48-      54 

ii 

377 

149-    158 

Cambridgeport, 

277 

1,240-1,376 

« 

277 

486 

Boston, 

130 

440-    480 

« 

200 

525 

Roxbury, 

180 

57-      60 

Somerville, 

67 

165 

Roxbury, 

750 

38 

main  sterile  for  several  days,  in  due  time  they  will  develop  one  or 
more  colonies.  An  entirely  sterile  plate  he  has  never  met  with. 
Professor  Percy  Frankland,  in  discussing  this  filter,  says  :  — 

"  It  must  be  regarded,  therefore,  still  as  an  open  question  whether  patho- 
genic organisms,  such  as  typhoid  bacilli,  can  or  cannot  grow  through  the 
pores  of  the  Chamberland  (Pasteur)  filter ;  and  until  this  question  has  been 
answered  in  the  negative,  it  is  obvious  that  in  using  these  cylinders  they  should 
be  frequently  cleaned  and  sterilized." 

*   Twenty-sixth  Annual  Report  Massachusetts  State  Board  of  Health,  p.  435. 


BACTERIAL   CONTENTS  OF   VARIOUS    WATERS, 


45 


Not  having  the  details  of  the  Freudenrich  tests,  it  is  impos- 
sible to  compare  the  results  from  abroad  with  those  obtained  here. 
Tests  of  Pasteur  filters,  in  such  condition  as  they  are  found  in 
hotels  and  restaurants,  have  given  from  180  to  1,500  bacteria  per 

BACTERIAL   CONTENTS   OF   WATER   FROM   DRIVEN   WELLS. 

(From  Examinations  by  Author.) 


DATE. 

LOCATION. 

GROWTH  ON 
GELATIN, 
DAYS. 

DEPTH  OF 
WELL  it: 
FEET. 

COLONIES 

PER    C.    C. 

OF  WATER. 

REMARKS. 

1895 

Lebanon,  O. 

5 

62 

260-1060 

Boring  No.  7. 

1895 

Wyoming,  O. 

34 

146 

109 

.  .   . 

1895 

Lebanon,  O. 

5 

115 

7 

Boring  No.  12. 

" 

« 

8 

115 

4 

<( 

(( 

« 

11 

115 

8 

(4 

1895 

St.  Maryls,  O. 

5 

265 

3-    14 

In  lime  rock. 

it 

" 

74 

265 

3-     14 

" 

n 

« 

9| 

265 

6-     14 

« 

M 

14 

5 

280 

53-    67 

14 

1896 

Dayton,  Ky. 

54 

82 

34 

Dayton  sandbar. 

14 

« 

54 

82 

38 

<( 

« 

it 

54 

82 

39 

" 

1896 

Dayton,  O. 

44 

70 

1 

Pumping. 

« 

M 

44 

70 

52 

.   .   . 

(( 

II 

44 

70 

60 

Natural  flow. 

" 

14 

44 

70 

66 

n 

<( 

(1 

4 

70 

146-  149 

« 

M 

(( 

5 

70 

31-    39 

After    72    hours   of 

pumping. 

1896 

Wyoming,  O. 

4 

146 

7 

From  discharge  pipe 

of     pump     while 

pumping. 

« 

(i 

4 

146 

73-    75 

From  tap,  residence. 

1897 

Wyoming,  O. 

4 

146 

285-  305 

«(       «         <t 

(( 

" 

9 

146 

2.6-   7.8 

From  discharge  pipe 

of  pump. 

cubic  centimeter  ;  and  the  low  counts  of  2  to  4  bacteria  per  cubic 
centimeter  have  been  obtained  from  tubes  not  previously  used. 

In  regard  to  Freudenrich's  *  experiments  with  water  from  the 
Pasteur  filter,  unfortunately  we  have  the  results  of  his  investiga- 
tions without  the  details  as  to  nutrient  media  employed,  or  tem- 

*  Fire  and  Water,  Nov.  3,  1894. 


46  THE   PURIFICATION  OF   WATER. 

perature  and  time  allowed  for  the  colonies  to  develop  in  the 
inoculated  gelatin  (or  other  media).  If  Freudenrich's  inocula- 
tions were  made  in  the  standard  gelatin-peptone  solution,  and  the 
plates  or  dishes  were  examined,  as  is  customary,  at  the  end  of 
three  or  four  days,  one  can  understand  how  such  plates  might 
show  no  growth  at  all  ;  but  if  the  examinations  be  delayed  for  a 
week  or  ten  days,  we  should  expect  to  find  colonies  of  water  bac- 
teria appearing  on  such  plates. 

From  his  own  experiments  with  water  from  new  Pasteur  filter- 
tubes,  the  author  has  never  failed  to  find  colonies  of  water  bacteria, 
if  sufficient  time  is  given  for  these  to  develop  ;  and  this  may  be 
partly  accounted  for  by  the  nutrient  properties  of  the  gelatin,  and 
the  great  difference  in  time  of  growth  between  different  bacteria 
found  in  water,  some  appearing  in  twenty-four  hours,  while  others 
require  from  one  to  three  weeks  to  grow.  If  a  plate  is  planted 
with  slow-growing  bacteria,  an  examination  of  such  plate  at  the 
end  of  four  days  may  reveal  no  colonies  at  all,  and  such  water 
would  incorrectly  be  declared  sterile.  For,  evidently,  if  any  water 
bacteria  are  found  growing  on  the  plate  after  being  kept  for  two 
or  three  weeks  in  the  moist  chamber  at  room  temperature,  such 
bacteria  must  have  been  in  the  water  when  the  plate  was  inocu- 
lated. Of  course  it  is  assumed  in  such  cases  that  the  plate  has 
been  carefully  guarded  against  the  introduction  of  adventitious 
germs. 

Stone  disk  and  tube  filters,  of  which  quite  a  number  of  forms 
are  now  being  made  and  sold,  are  not  to  be  regarded  as  germ 
proof,  although  so  labeled  ;  and  from  the  treatment  which  they 
receive  after  being  introduced  into  a  residence,  they  usually  be- 
come a  positive  menace  to  the  health  of  the  family  dependent 
upon  them  for  their  drinking-water.  It  is  not  denied  that  these 
filters  are  successful  in  clarifying  turbid  waters  ;  but  a  collection 
of  sponges  will  do  the  same  thing,  and  no  one  supposes  that  a 
sponge  filter  will  restrain  the  passage  of  bacteria.  Water  may  be 
rendered  perfectly  limpid  by  filtration ;  but  colorless  or  clear  water, 
and  pure  or  purified  water,  are  not  the  same. 

Clarified  water  may  be  the  carrier  of  pathogenic  bacteria  quite 
as  well  as  turbid  water ;  while  turbid  water,  apart  from  the  inor- 


BACTERIAL    CONTENTS   OF   VARIOUS    WATERS. 


47 


ganic  substances  (in  solution  or  suspension)  wliich  gives  it  color, 
may  be  very  pure.  Clarification  and  filtration  are  not  one  and  the 
same  thing  ;  although,  as  a  rule,  properly  filtered  water  usually  is 
colorless,  unless  the  color  is  derived  from  peaty  substances,  in 
which  event  the  hygienic  quality  may  be  greatly  improved  by  fil- 
tration without  removing  the  color. 


BACTERIA   IN    WATER    FROM    DOMESTIC    FILTERS. 


STONE  DISK  FILTERS, — 


DATE. 


DAYS  OF  GROWTH      COLONIES  PER 
ON  GELATIN.       C.  C.  OF  WATER. 

1.  Sept.     2,  1894,  5|  19,035-48,600 

This  filter  in  a  very  popular  restaurant,  with  the  legend  on  the  menu :  "  The  water  of  this 
establishment  is  filtered  through stone  filter,  and  is  absolutely  pure." 

2.  Dec.    18,  1894,  5  3^859-5,733 

This  filter  in  private  residence  filtering  cistern  water. 

3.  July     12,  1895,  4  11,704-14,605 

Same  as  No.  2. 

4.  July    20,  1895,  4  29,765 

Same  as  Nos.  2  and  3. 

5.  April  12,  1896,  5£  2,873-3,628 

New  filter  in   service  few  hours  before  sample  was  taken 
which  offers  its  patrons  pure  filtered  water. 

6.  Dec.      9,  1896,  5  1,299-1,308 

Filter  in  residence. 


this  also  is  in  a  restaurant 


STONE  TUBE  FILTER,  — 

7.  July    17,  1895,  4 

8.  July     19,  1895,  6 

9.  July     21,  1895,  8 

SAND  FILTERS,— 

10.  May    21,  1895,  4 

In  restaurant. 

11.  Dec.    17,  1895,  7 

Experimental  filter. 

12.  Jan.        1,  1896,  7 

Experimental  filter. 

13.  Sept.    20,  1896,  2 


125-175     Showing  effect  of 
335-440     time  on  development 
410-535     of  colonies. 


153-176-180  Without  coagulant. 

30-34-36  With  coagulant. 

20-85  «            « 

77-105  «            " 


This  sample  of  water  reported  by  chemist  as  being  free  from  alb.  ammonia. 


SAND  AND  CHARCOAL  FILTER, — 
14.  March  30,  1896,  3 

Filter  in  residence. 


2,445-2,512 


48  THE   PURIFICATION  OF   WATER. 

It  will  be  noted  that  the  number  of  colonies  from  a  given 
water  sample  depends  upon  the  days  which  the  plate  is  permitted 
to  grow  before  the  count  is  made.  Referring  to  the  stone  tube  fil- 
ter, the  water  from  which  was  tested  July,  1895,  by  prolonging  the 
growth  from  four  to  eight  days,  the  count  was  increased  more  than 
three  times  ;  and  all.  the  colonies  finally  found  on  these  plates  were 
due  to  bacteria  in  the  water  at  the  time  of  inoculation.  The  same 
increased  growth  due  to  time  of  inoculation  is  strikingly  shown  in 
the  following  table  of  bacteria  from  spring  waters,  where  in  one 
instance  the  count  rose  from  424  at  the  end  of  two  days  to  1,440 
at  the  end  of  six  days.  Other  illustrations  of  the  influence  of  time 
on  the  counts  will  be  noted  in  the  several  tables  of  bacterial  con- 
tents vyf  various  waters. 

Spring  waters  sold  in  Cincinnati  for  table  use  have  given  the 
following  results  when  tested  for  bacterial  contents  :  — 

SPRING   WATER. 

(Samples  collected  at  the  source,  and  planted  within  two  hours.) 

DATE.  SPRINGS.  .  DAYS  OF  GROWTH  BACTERIA  PER 

ON  GELATIN.  C.  C.  OF  WATER. 

Sept.  2,  1895,         Tallewanda,  Ohio,  4  128-148 

Nov.  3,      "  "  "  4  85-402 

(From  Bottled  Spring  Water.) 

Geneva  bottled  spring  water,  planted  Aug.  1,  1895,  gave  the 
following  results  :  — 

Counted  at  end  of  2  days,  424  colonies  per  c.  c.  of  water. 

«                u         4     «  \  024         "         "         "         " 

«                «         5     «  1,160         "         "         "         " 

«               «         6     "  1,440         "         "         "         " 

Dr.  T.  M.  Drown,  from  analyses  of  forty-one  spring  waters  in 
Massachusetts,*  found  :  — 

2  springs  contained  1  bacteria  per  c.  c.  of  water  each. 

5         a  u  2  "  "  " 

7         «  "         an  average  of          7  u  "  " 

Q  u  u  u  u  16  "  "  " 

7         u  «  «         u  29  "  "  " 

Q  u  u  u  u  70  <t  <<  « 

*   Twenty-third  Annual  Report  Massachusetts  State  Board  of  Health,  p.  356. 


BACTERIAL    CONTENTS    Of    VARIOUS    WATERS. 


49 


3  springs  contained  an  average  of  159  bacteria  per  C.  C.  of  water  each. 

1          «  "  "  259  "  "  " 

1          «  «  446  «  «  « 

1  u  «  u  973  H  a  n 

2  "  "  "         •     1,844  "  "  " 

Professor  W.  T.  Sedgwick  *  has  examined  the  water  in  a  number 
of  springs  in  the  country  district  of  southern  New  Hampshire  with 
the  following  results  :  — 


No. 

DATE  OF 
ANALYSIS. 

BACTERIA  PER  C.  C.  OF  WATER 

On  Gelatin. 

On  Agar. 

1 

Nov.  29,  1894, 

252-258 

145-167 

2 

« 

134-163 

133 

3 

« 

92-105 

72-  79 

4 

« 

95-106 

89-  96 

5 

« 

193-218 

203-217 

6 

tt 

43-100 

36-  72 

The  author,  in  searching  for  b.  typhosus  and  allied  organisms 
in  the  Ohio  River  water,  has  made  several  tests  with  the  solution 
proposed  by  Parietti  for  destruction  of  the  non-pathogenic  bacteria 
in  water,  with  the  results  as  given  in  the  table  on  page  50.  The 
influence  of  varying  quantities  of  the  acid  solution  is  distinctly 
shown  by  the  test  of  Jan.  5,  1896. 

The  test  of  Aug.  7,  1895,  indicates  the  influence  of  time  on 
plates  inoculated  with  Ohio  River  water,  after  treatment  of  the 
gelatin  with  a  strong  dose  (Jfa  c.c.)  of  the  Parietti  solution.  At 
the  end  of  four  days  (the  usual  time  of  incubation  of  water  bac- 
teria at  room  temperature)  no  growth  at  all  had  occurred,  while 
three  days  later  twelve  colonies  had  appeared,  and  three  days  later 
than  this  the  growth  had  increased  six  times.  In  endeavoring  to 
reduce  the  number  of  bacteria  in  a  water  sample  by  dosing  the 
gelatin  with  the  Parietti  solution,  considerable  care  must  be  exer- 
cised to  avoid  the  destruction  of  the  typhoid  bacillus  if  it  be  pres- 
ent. It  is  well  known  that  several  other  organisms  will  resist 
larger  doses  of  the  acid  solution  ;  and  upon  any  plate,  when  search 
is  being  made  for  b.  typhosus,  one  must  expect  to  find  several  other 

*   Twenty-sixth  Annual  Report  Massachusetts  State  Board  of  Health,  p.  43(5  et  seq. 


50 


THE  PURIFICATION  OF   WATER. 


bacteria,  if  the  latter  happen,  as  is   usual,  to  be  present  in  the 
water. 

It  is  commonly  supposed  that  freshly  fallen  rain-water  contains 
few  bacteria.  According  to  Miquel  (Paris),  rain-water  at  Mont- 
souris,  in  the  suburbs  of  the  city,  contained  4.3  bacteria  per  cubic 
centimeter,  while  rain-water  caught  in  the  middle  of  the  city  con- 
tained 19  bacteria  per  cubic  centimeter. 

INFLUENCE  OF  PARIETTI  SOLUTION  ON  GROWTH  OF  BACTERIA. 
CINCINNATI,  OHIO,  TAP  WATER. 


DATE. 

DAYS  OF 
GROWTH  ON 
GELATIN. 

KIND  OF  WATER. 

COLONIES  PER 
C.  C.  OF  WATER. 

Aug.    7,  1895, 

4 

Plain  water, 

804 

Aug.    7,     « 

4 

City  water  in  10  c.  c.  of  15%  gelatin 

treated   with    y\  c-    c-    of    Parietti 

solution, 

No  growth. 

Aug.  10,  1895, 

7 

«    * 

12 

Aug.  13,     « 

10 

" 

72 

Dec.  12,     « 

5 

Plain  water, 

2,455-3,295 

Dec.  12,     " 

5 

City   water    treated   with   6  drops  = 

i  c.  c.  of  Parietti  solution  in  10  c.  c. 

of  10%  gelatin, 

25-      29 

Dec.  15,  1895, 

n 

Plain  water, 

3,146-4,825 

Dec.  15,     " 

7J 

City   water   treated   with   6   drops  = 

i  c.  c.  of  Parietti  solution  in  10  c.  c. 

of  10%  gelatin, 

59-    119 

Jan.     5,  1896, 

18 

City   water    treated   with  4  drops  — 

^  c.  c.  of  Parietti  solution  in  10  c.  c. 

of  10%  gelatin, 

853 

Jan.      5,  1896, 

18 

City    water    treated    with   5  drops  = 

I  c.  c.  of  Parietti  solution  in  10  c.  c. 

of  10%  gelatin, 

658 

Jan.     5,  1896, 

18 

City    water    treated    with  6  drops  = 

i  c.  c.  of  Parietti  solution  in  10  c.  c. 

of  10%  gelatin, 

227 

The  author,  however,  finds  that  the  numbers  of  bacteria  in 
rain-water  depend  upon  the  time  at  which  the  collection  of  the 
sample  is  made.  If  at  the  beginning  of  a  shower,  the  numbers 
may  be  high,  while  after  a  few  hours  of  rainfall  the  atmosphere 
appears  to  have  been  washed  of  its  bacterial  contents,  when  the. 


BACTERIAL    CONTENTS   OF   VARIOUS    WATERS. 


51 


numbers  become  very  low.  The  notes  below  illustrate  the  influ- 
ence of  time  of  rainfall  upon  the  bacterial  contents  of  the  water. 
The  author's  samples  were  collected  in  the  suburbs  of  Cincinnati, 
where  the  conditions  were  quite  like  those  of  the  country. 

Fresh  rain-water  from  short  shower  caught  in  sterilized  bottle  placed 
on  the  ground  clear  of  trees  and  houses. 

DATE  OF  TEST.  DAYS  OF  GROWTH.  COLONIES  PER  C.  C. 

July  22,  1895.  4  5,495-5,759. 

A  sample  of  rain-water  collected  July  28,  1895,  on  4  days' 
growth,  gave  414  molds  and  624  colonies  per  cubic  centimeter. 

Rain-water  collected  at  end  of  twelve  hours  of  rainfall. 

DATE.  DAYS  OF  GROWTH.  COLONIES  PER  C,  C. 

July  12,  1896,  3i  15-18 

July  13,  1896,  4i  54-57 

As  further  interesting  information  upon  the  chemical  quality  of 
freshly  fallen  rain-water,  the  following  analyses  by  Dr.  Thomas  M. 
Drown  are  quoted  :  — 

CHEMICAL  ANALYSIS  OF  RAIN-WATER* 

(Parts  per  100,000.) 


DATE. 

STATION. 

AMMONIA. 

NITROGEN  AS 

CHLO- 
RINE. 

Free. 

Albuminoid. 

Nitrates. 

Nitrites. 

1888. 

July       7, 

North  Andover, 

.0047 

.0038 

.0070 

.0000 

.    .    . 

Sept.  18, 

«             <( 

.0016 

.0026 

.0040 

.0000 

.  .  . 

Sept.  12, 

Lawrence, 

.0298 

.0024 

.0000 

.0000 

.007 

Oct.     2, 

« 

.0414 

.0030 

.0100 

.0000 

.    .    . 

Nov.  27, 

« 

.0164 

.0014 

.0050 

.0002 

.360 

1889. 

May  21, 

Lawrence, 

.0086 

.0026 

.0030 

.0001 

.070 

June   17, 

Jamaica  Plain,  Boston, 

.0564 

.0152 

.0180 

.0004 

.130 

1890. 

Mar.  28, 

Newton  Highlands, 

.0154 

.0034 

.0050 

.0001 

.060 

1887. 

Dec.  26, 

Boston  (snow), 

.0258, 

.0038 

.0030 

*  Massachusetts  State  Board  of  Health,  1890,  Part  I.,   "  Report  on  Water   Supply  and 
Sewerage,"  p.  562.  • 


52  THE   PURIFICATION  OF   WATER. 

Quite  a  profitable  business  has  been  established  in  several  of 
the  larger  cities  in  the  manufacture  and  sale  for  table  use  of  dis- 
tilled water.  A  test  of  such  water  as  supplied  in  Cincinnati  gives 
a  very  favorable  result  :  — 

DISTILLED   WATER.     (Single  Distillation.) 

DAYS  OF  GROWTH        BACTERIA  PER  C.  C. 
DATE-  ON  GELATIN.  OF  WATER. 

Oct.  29,  1895,  4  30-52 

Oct.  31,  1895,  6  38-80 

The  following  water  was  suspected  of  having  caused  typhoid 
fever  in  one  of  the  State  institutions  of  Ohio  :  — 

(Sample  taken  from  tap  in  Superintendent's  Office.) 

DAYS  OF  GROWTH        BACTERIA  PER  C.  C. 
DATE. 

ON  GELATIN.  OF  WATER. 

Sept.  11,  1896,  3  845-862-897 

Many  of  the  above  colonies  were  rapid  liquefiers,  compelling 
the  count  of  the  dishes  at  end  of  three  days  to  avoid  complete  loss 
of  test. 

Same  water  tested  Sept.  29,  four  days  growth  on  gelatin. 

One  dish  gave  239  bacteria  per  cubic  centimeter  of  water. 

Second  dish,  gelatin  wholly  liquefied  and  count  impossible. 

Some  tests  of  the  influence  of  a  small  Anderson  Revolving  Iron 
Purifier  on  water  from  the  Ohio  River  gave  results  as  follows  :  — 

ANDERSON    REVOLVING   IRON    PURIFIER. 
(Laboratory  Test  of  Ohio  River  Water.) 

DAYS  OF  GROWTH  COLONIES  PER  C.  C. 

DATE.  KIND  OF  WATER.  QN  GELATIN.  OF  WATER. 

June  29,  1896,  Plain  city  water,  4  2,304-2,832 

"  "  Anderson  Purifier,  4  50-  90 

July  4,  1896,  Plain  city  water,  4  495-  644 

"  "  Anderson  Purifier,  4  39-  119 

Reference  will  be  made  to  this  performance  again  in  discussion 
of  this  mode  of  water  purification  ;  but  at  this  point  it  should  be 
remarked,  that  the  conditions  under  which  the  experiments  were 
conducted  did  not  favor  the  best  performance  of  the  device,  but 


BACTERIAL    CONTENTS   OF   VARIOUS    WATERS.  53 

were  deemed  sufficient  to  indicate,  in  a  rough  way,  how  the  con- 
tact of  the  fragments  of  iron  in  the  purifier  aided  in  the  removal, 
by  subsequent  sand  filtration,  of  the  larger  percentage  of  the 
bacteria  contained  in  the  raw  water. 

Artificial  ice  made  from  distilled  water  is  now  largely  sold  in 
many  cities,  particularly  where  the  climate  is  prohibitory  of  the 
collection  of  ice  from  lakes  and  ponds.  A  test  of  such  ice,  as 
supplied  in  the  city  of  Cincinnati  and  vicinity,  is  given  below :  — 

TESTS   OF  ARTIFICIAL   ICE   SUPPLIED   IN    CINCINNATI. 

DAYS  OF  GROWTH  COLONIES  PER  C.  C. 

ON  15,%  GELATIN.  OF  WATER. 

July  12,  1896,  3£  17-  37 

July  13,  1896,  4£  99-105 

In  testing  water  samples  for  bacterial  contents,  in  addition  to 
the  usual  precautions  to  avoid  contamination  from  the  atmosphere, 
it  is  advisable  to  make  an  occasional  test  of  the  air  of  the  work- 
room, as  a  guide  to  the  probable  amount  and  kinds  of  organisms 
which  might  accidentally  come  into  a  sample  under  observation. 
Such  tests  by  the  author  indicate  a  considerable  variation  in  the 
numbers  of  air  germs  which  will  fall  on  an  open  sterile  gelatin 
plate  in  the  same  room  at  different  times. 

BACTERIAL   CONDITION   OF  AIR   OF  WORKROOM. 

DATE.  TIME  OF  EXPOSURE.         GROWTH.  MOLDS.         COLONIES. 

July   14,  1894,          10  minutes,  4  days,  26  69 

Nov.  15,  1895,         15       «  9     «  2  43 

Mar.  29,  1896,         15  7     "  2  4 

Certain  experiments  have  shown  sunlight  to  be  a  powerful 
agent  in  the  destruction  of  nearly  all  forms  of  bacterial  life. 
With  respect  to  the  influence  of  sunlight  on  the  bacterial  life  in 
river  water,  Dr.  E.  Frankland,  in  his  "  Report  on  the  Quality  of 
London  Waters  for  1895,"  says:*  — 

"  With  regard  to  the  effect  of  sunshine  upon  bacterial  life,  the  interesting 
observations  of  Dr.  Marshall  Ward  leave  no  doubt  that  sunlight  is  a  powerful 
germicide ;  but  it  is  obvious  that  its  potency  in  this  respect  must  be  greatly 

*  Annual  Summary  of  Vital  Statistics,  London.  1895,  p.  67. 


54  THE   PURIFICATION  OF   WATER. 

diminished,  if  not  entirely  annulled,  when  the  solar  rays  have  passed  through 
a  stratum  of  water  even  of  comparatively  small  thickness  before  they  reach 
the  living  organisms.  By  a  series  of  ingeniously  contrived  experiments  Mr. 
Burgess  has  demonstrated  the  correctness  of  this  view.  A  sterile  bottle  was 
half  filled  with  Thames  water,  and  violently  agitated  for  five  minutes  to  insure 
equal  distribution  of  the  organisms.  Immediately  afterwards  a  number  of 
sterile  glass  tubes  were  partially  filled  with  this  water,  and  sealed  hermetically. 
Three  of  these  tubes  were  immediately  packed  in  ice,  and  the  remainder  were 
attached  in  duplicate,  at  different  distances  apart,  to  a  light  wire  frame,  which 
was  then  suspended  vertically  in  the  river.  The  experiments  were  made  near 
the  Grand  Junction  Water  Company's  intake,  at  a  place  favorable  for  the  sun's 
rays  to  fall  on  the  river  without  any  obstruction.  The  river  was  at  that  time 
in  a  very  clear  condition,  and  contained  but  little  suspended  matter,  while  the 
day  was  fine,  although  clouds  obscured  the  sun  occasionally.  The  tubes  were 
exposed  to  light  in  the  river  for  four  and  a  half  hours  (from  10.30  A.M.  to  3  P.M., 
on  May  15,  1895).  At  the  end  of  this  time  the  tubes  were  packed  in  ice  for 
transport  to  the  laboratory,  where  the  cultivation  was  started  immediately.  The 
colonies  were  counted  on  the  fourth  day,  and  yielded  the  following  numbers  :  — 

COLONIES  PER  C.  C. 


OF   WATER. 


Thames  water  packed  in  ice  immediately  after  collection,  2,127 

«  "      after  exposure  to  sunlight  for  4|  hours  at 

surface  of  river,  1,140 

"  "      after  exposure  to  sunlight  for  4|  hours  at 

6  inches  below  surface  of  river,  1,940 

"  «      after  exposure  to  sunlight  for  4|  hours  at 

1  foot  below  surface  of  river,  2,150 
"           "      after  exposure  to  sunlight  for  4£  hours  at 

2  feet  below  surface  of  river,  2,430 
«           "      after  exposure  to  sunlight  for  4^  hours  at 

3  feet  below  surface  of  river,  2,440 

These  experiments  show  that  on  the  15th  of  May  the  germici- 
dal  effect  of  sunlight  on  Thames  microbes  was  nil  at  depths  of  one 
foot  and  upwards  from  the  surface  of  the  water.  It  cannot  there- 
fore excite  surprise  that  the  effect  of  sunshine  upon  bacterial  life 
in  the  great  mass  of  Thames  water  should  be  nearly,  if  not  quite, 
imperceptible. 

Upon  the  contrary,  the  influence  of  sunlight  on  the  contents  of 
shallow  reservoirs  has  been  held  to  exert  a  very  perceptible  effect 
on  bacterial  life  in  the  water.  Bacteriological  cultivation  is  usu- 
ally conducted  in  cupboards  or  incubators,  from  which  the  light  is 


BACTERIAL    CONTENTS  OF   VARIOUS    WATERS.  55 

rigorously  excluded  to  avoid  the  inhibiting  influence  of  light  upon 
the  cultures,  and  this  effect  is  known  to  be  due  to  light  indepen- 
dent of  heat  from  the  sun's  rays  ;  and  one  would  have  supposed 
that  in  clear  water,  through  which  the  light  would  penetrate  for 
some  distance,  a  stronger  influence  would  have  been  manifested 
than  is  shown  by  the  experiment  quoted. 

That  the  effect  of  sunlight  is  held  by  some  experienced  inves- 
tigators to  be  of  value  in  the  reduction  of  bacterial  life  in  polluted 
waters,  is  apparent  by  the  following  quotation  from  a  letter  to  the 
author  by  Mr.  Rud  Schroder,  inspector  of  the  Hamburg  Water- 
Works:— 

11  In  such  places,  where  the  winter  temperatures  do  not  vary  from  ours 
[Hamburg],  I  believe  open  filters  are  to  be  preferred  on  account  of  their  facil- 
ity in  being  worked  and  cleaned  ;  and  last,  but  not  least,  in  regard  to  their  bac- 
teriological efficiency  due  to  the  rays  of  the  sun." 


56  THE  PURIFICATION  OF   WATER. 


CHAPTER    IV. 

THE   TYPHOID   BACILLUS    AND   TYPHOID   FEVER. 

THE  connection  of  b.  typlwsus  with  the  etiology  of  typhoid 
fever  is  now  so  well  established,  and  the  relation  of  polluted  water 
supplies  to  typhoid  fever  so  generally  recognized,  that  a  brief  review 
of  the  chief  characteristics  of  this  bacillus  and  allied  organisms 
found  in  water  will  not  be  inappropriate. 

B.  typhosus,  obtained  from  a  human  spleen,  will  give  the  fol- 
lowing characteristics  :  — 

(1)  The  bacillus  will  not  liquefy  gelatin. 

(2)  It  will  not  coagulate  sterilized  milk. 

(3)  It  will  not  produce  gas  when  cultivated  in  glucose  bouillon 
in  the  fermentation  tube. 

(4)  It  will  not  give  the  indol  reaction. 

(5)  When  grown  in  a  peptone  solution  containing  potassium 
nitrate,  it  is  said  to  reduce  nitrate  to  nitrite.* 

(6)  Under  the  microscope  drop  cultures  show  great  activity 
of  the  bacillus.      (This  the  author  finds  depends  upon  the  age  of 
the  culture ;    cultures   near   the   original   source   (spleen)  exhibit 
greater  motility  than   old    cultures,   and    in    degenerate   cultures 
motility  seems  to  be  no  longer  a  property  of  the  bacillus.) 

(7)  The  vacuoles,  or  unstained  spaces  in  the  plasma,  are  rarely 
absent. 

(8)  Filaments  are  often  found  in  stained  young  cultures. 
The  invisible  growth  on  sterilized  potato  is  no  longer  regarded 

as  a  test  in  differentiation  of  the  typhoid  bacillus.  Other  germs 
will  give  the  same  effect,  and  the  invisible  growth  is  not  constant 
even  with  the  typhoid  organism. 

In  chemical  composition  the  typhoid  bacillus  is  not  known  to 
differ  from  the  harmless  bacteria.  Under  the  microscope  it  resem- 

*  Annual  Report  Massachusetts  State  Board  of  Health,  1891,  p.  641. 


THE    TYPHOID   BACILLUS  AND    TYPHOID   FEVER.  57 

bles  a  diminutive  rod  with  round  ends,  of  length 'about  three  times 
the  width.  The  length,  however,  is  not  uniformly  three  times  the 
width  ;  for  longer  and  shorter  individuals  will  be  seen  on  cover  glass 
preparations,  and  not  infrequently  long  threads  or  undivided  fila- 
ments will  be  noticed  in  preparations  from  young  cultures.  Nu- 
merous flagella,  or  whiplike  appendages,  spring  from  the  cellulose 
envelope,  and  endow  the  bacilius  with  motility.  When  stained  with 
carbol-fuchsin  the  bacillus  appears  as  a  brilliant  red  rod. 

In  looking  for  the  typhoid  bacillus  in  a  sewage-polluted  water, 
in  addition  to  certain  non-pathogenic  organisms  resembling  b. 
typhosus  in  some  respects,  one  is  very  liable  to  encounter  two 
other  germs  nearly  identical  with  the  typhoid  bacillus.  These  are 
b.  coli  communis  and  b.  lactis  aerogenes. 

These  three  bacilli  resemble  (or  differ  from)  each  other  in  the 
following  respects  :  — 

(1)  All  are  non-liquefiers.     That  is  to  say,  all  bacteria  will 
either  (a),  grow  in  gelatin  and  liquefy  the  material,  or  (£),  will 
grow  in  the  material  without  liquefying  it. 

(2)  While  there  is  a  distinct   difference  between   the  three 
bacilli  in  microscopic  appearance,  and  b.  coli  communis  and  b.  lactis 
aerogenes  seem  to  have  definite  proportions  not  easily  mistaken, 
the  typhoid  bacillus  possesses  such  vagaries  of  proportion  that  at 
times  it  seems  to  resemble  closely  the  other  germs.     Although 
b.  coli  communis  is  always  thinner  than  the  typhoid  bacillus,  and 
b.  lactis  aerogenes  always  shorter,  the  length  of  b.  coli  communis 
often   agrees   with   the   length   (from  a  parallel   culture)   of   the 
typhoid  bacillus,  and  the  width  of  b.  lactis  aerogenes  is  about  the 
same  as  the  typical  typhoid  rod,  while  all  have  rounded  ends. 

(3)  All  grow  in  gelatin   stick  cultures  quite  alike. ;  b.  lactis 
aerogenes  the  quickest  and  most  luxuriantly,  and  b.  typhosus  the 
slowest  and  with  least  energy.      Between  b.  typhosus  and  b.  lactis 
aerogenes,  b.  coli  communis  occupies  a  middle  ground.     All  produce 
a  dirty  white  expansion  on  sloped  agar. 

(4)  When  cultivated  in  glucose  bouillon  in  the  fermentation 
tube,  these  organisms  grov/  equally  well  in  the  presence  or  absence 
of  air;  the  bouillon  in  the  open  leg  (exposed  through  the  cotton 
plug  to  the  air),  and  in  the  closed  leg  (from  which  all  air  has  been 


58  THE  PURIFICATION  OF   WATER. 

removed  during  the  sterilization  of  the  contents  of  the  tube), 
exhibiting  similar  turbidity.  When  the  allied  germs,  b.  coli  coin- 
munis  and  b.  lactis  aerogenes,  are  cultivated  in  the  fermentation 
tube,  an  abundance  of  gas  is  produced  in  the  closed  leg,  while  the 
typhoid  bacillus,  when  so  grown,  produces  no  gas  ;  and  this  test 
has  been  proposed  by  Dr.  Theobald  Smith  *  for  the  identification 
of  b.  typhosus. 

When  the  test  is  one  to  determine  whether  a  certain  germ  is 
the  typhoid  bacillus  or  b.  coli  communis,  the  fermentation  tube  will 
settle  the  question  ;  but  alone  it  will  not  determine  whether  a  sus- 
pected germ  found  in  water  is  the  typhoid  bacillus  or  some  other 
organism.  In  Ohio  River  water  the  author  has  found  bacilli  which 
grow  in  the  fermentation  tube  quite  like  the  typhoid  bacillus,  but 
which  are  known  by  further  tests  not  to  be  this  germ. 

(5)  When  the  typhoid  bacillus  is  grown   in   sterilized   milk 
having  a  slightly  acid  reaction,  it  will  increase  the  acidity  per- 
ceptibly, but  neither  in  the  presence  nor  absence  of  heat  will  the 
milk  be  coagulated  ;  while  b.  coli  communis,  when  grown  in  milk, 
produces  a  large  increase  of  acidity,  and  sometimes  coagulates  the 
milk  in  the  tube  at  room  temperature,  and  always  coagulates  the 
milk  upon  the  application  of  heat  for  a  few  minutes. 

(6)  When  cultivated  in  gelatin  or  agar  to  which  one  or  two 
per  cent  of  glucose  is  added,  the  typhoid  bacillus  will  grow  more 
luxuriantly  than  in  plain  gelatin,  but  produces  no  gas,  while  b.  coli 
communis  and  b.  lactis  aerogenes,  when  so  cultivated,  produce  an 
abundance  of  gas. 

(7)  B.  typhosus  in   drop   cultures   is   possessed   of  great   ac- 
tivity, executing  within   the  field   of  the   microscope  motions  of 
translation  and  rotation,  and  sinuous  movements  to  and  fro  ;  b. 
coli  communis  has  a  sluggish  motion,  wholly  unlike  that  of  the 
typhoid   organism  ;   while  b.   lactis  aerogenes  is  not   possessed  of 
motility  at  all. 

(8)  All  of  these  organisms  are  said  to  be  found  in  the  dejecta 
of  man,  and   b.  coli  communis  and  b.  lactis  aerogenes  also  in  the 
dejecta  of  animals. 

*  The  Fermentation  Tube,  by  Theobald  Smith,  Washington,  B.C.,  1893. 


THE    TYPHOID  BACILLUS  AND    TYPHOID  FEVER. 


59 


The  following  experiments  by  the  author  wifh  b.  typhosus  and 
b.  coli  communis  in  sterilized  milk  throw  some  light  upon  the  re- 
spective acid-resisting  properties  of  these  organisms  :  — 

TESTS   OF   B.    TYPHOSUS   AND   B.    COLI    COMMUNIS   IN    STERILIZED   MILK. 

(Acidity  of  5  c.  c.  of  milk  tested  before  sterilization  with  a  j1^  normal  solution  of 
caustic  soda.  All  cultures  grown  at  room  temperature.) 

Five  cultures  were  used :  — 

(A)  B.  typhosus  obtained  from  Dr.  T.  M.  Prudden,  New  York. 

(B)  B.  typhosus  obtained  from  Dr.  O.  L.  Cameron,  Cincinnati. 

(C)  B.  typhosus  obtained  from  Dr.  O.  L.  Cameron,  Cincinnati. 

(D)  B.  coli  communis  obtained  from  Dr.  O.  L.  Cameron,  Cincinnati. 

(E)  B.  typhosus  obtained  from  spleen,  Cincinnati  Hospital. 


DATE. 

CULTURE. 

ORIGINAL 
ACIDITY  OF 
MILK. 

DAYS 

OF 

GROWTH. 

FINAL 
ACIDITY  OF 
MILK.* 

INCREASE 

OF 

ACIDITY.* 

1894 

Dec.  24, 

A  (2) 

0.75 

4| 

0.775 

0.025 

" 

B 

0.75 

4| 

0.825 

0.075 

14 

C 

0.75 

H 

0.925 

0.175 

« 

C 

0.75 

0.950 

0.200 

1895 

Jan.     1, 

A 

0.80 

4 

0.910 

0.110 

" 

A 

0.80 

4 

0.930 

0.130 

« 

B 

0.80 

4 

1.100 

0.300 

Jan.   21, 

B(2) 

0.70 

5 

0.800 

0.100 

" 

D 

0.70 

5 

2.400 

1.700 

" 

D 

0.70 

5 

2.500 

1.800 

Jan.   26, 

A 

0.70 

5 

0.950 

0.250 

(C 

A 

0.70 

5 

0.850 

0.150 

Mar.    2, 

E 

0.70 

6 

0.900 

0.200 

« 

E 

0.70 

6 

0.880 

0.180 

Mar.    8, 

A 

0.70 

4 

0.975 

0.275 

" 

E 

0.70 

4 

0.925 

0.225 

June    6, 

A 

0.70 

5 

0.900 

0.200 

" 

E(3) 

0.70 

5 

1.000 

0.300 

While  b.  typJwsus  will  grow  side  by  side  with  b.  coli  communis 
in  sterilized  milk  with  a  slight  increase  of  the  acidity  of  the  milk, 
the  latter,  on  the  contrary,  will  increase  the  acidity  of  milk  to  the 
point  of  coagulation. 

Culture  "  A  "  indicated  an  increase  of  22  per  cent  in  the  acid- 

*  Acidity  of  milk  stated  in  cubic  centimeters  of  caustic  soda  solution. 


60  THE  PURIFICATION  OF   WATER. 

ity  of  milk ;  culture  "  B  "  an  increase  of  21  per  cent ;  culture  "  C  " 
an  increase  of  25  per  cent;  culture  "E"  an  increase  of  30  per 
cent ;  and  culture  "  D  "  (b.  colt  communis)  indicated  an  increase 
of  233  per  cent  in  the  acidity  of  milk.  The  increase  of  acidity  of 
sterilized  milk  by  b.  coli  commimis  as  compared  with  b.  typhosits  is 
nearly  ten  to  one. 

Aside  from  the  able  demonstration  of  its  untenability  by  Dr. 
Dunbar,*  the  theory  which  prevailed  a  few  years  since  that  an  acid 
solution  might  be  made  in  which  b.  typhosus  would  develop,  while 
b.  coli  communis  would  perish,  is  clearly  shown  to  be  an  impossi- 
bility by  the  experiments  detailed  above.  The  difference  in  the 
increase  of  acidity  of  sterilized  milk  by  b.  typhosus  and  b.  coli  com- 
munis, however,  is  an  important  factor  in  the  differentiation  of 
these  organisms.f 

A  curious  circumstance  calculated  to  support  Professor  Lan- 
kester's  view  of  the  origin  of  b.  typhosus  is,  that  while  the  colon 
bacillus  has  been  often  found  in  polluted  waters,  the  typhoid  ba- 
cillus has  been  found  upon  very  rare  occasions,  and  considerable 
uncertainty  surrounds  quite  a  number  of  the  alleged  discoveries 
of  the  latter  bacillus  in  water  supplies.  Doubtless  in  all  cases  of 
sewage  pollution  of  water,  the  colon  bacillus  is  much  more  numer- 
ous than  the  typhoid  bacillus,  because  the"  former  may  come  into 
the  sewage  from  many  sources,  while  the  latter  can  come  only  from 
those  suffering  with  typhoid  fever,  and  even  in  such  cases  the 
bacillus  is  said  to  be  given  off  only  during  the  earlier  stages  of 
illness. 

B.  lactis  aerogenes,  likewise  a  bacillus  of  the  intestine,  by  its 
resemblance  in  several  respects  to  b.  typhosus  and  b.  coli  communis, 
is  very  liable  in  the  earlier  stages  of  differentiation  to  be  mistaken 
for  either.  It,  however,  may  be  determined  much  easier  that  a 
given  organism  is  b.  coli  communis  or  b.  lactis  aerogenes,  than  that 
it  is  b.  typhosus ;  and  this  difficulty  in  differentiating  a  germ  sup- 
posed to  be  b.  typhosus,  obtained  outside  the  animal  body,  is  a 

*  Zeitschrift  fiir  Hygiene,  1892,  p.  485. ' 

t   Twenty-third  Annual  Report  Massachusetts  State  Board  of  Health,  p.  640. 


THE    TYPHOID   BACILLUS  AND    TYPHOID  FEVER. 


61 


stumbling-block  in  the  way  of  direct  proof  ttfat  a  given  water 
supply  contains  the  typhoid  germ. 

The  rapidity  with  which  the  bacillus  usually  acts  when  inocu- 
lated into  the  lower  animals  renders  these  experiments  an  uncer- 
tain test  in  differentiation,  although  the  researches  of  Dr.  Alessi  * 
with  typhoid  cultures  on  guinea  pigs  show  that  considerable  time 
may  elapse  between  inoculation  and  death  of  these  animals.  These 
experiments  indicate  that  rats  which  die  survived  the  infection  from 
12  to  36  hours,  rabbits  from  24  hours  to  4  days,  while  guinea  pigs 
survived  the  inoculation  from  8  hours  to  13  days. 

The  investigations  of  Dr.  Alessi  show  that  while  putrid  gases, 
i.e.,  sewer  gas,  may  increase  the  susceptibility  of  the  lower  ani- 
mals to  typhoid  fever  infection,  they  cannot  be  considered  as  a 
cause.  Many  animals  were  experimented  upon  ;  and  with  the  ex- 
ception of  rats  first  exposed  to  the  influence  of  putrid  gases  and 
then  used  as  controls,  all  the  animals  not  inoculated  with  the 
typhoid  culture  recovered.  The  following  table  contains  a  rfeumt 
of  the  mortality  of  the  animals  from  these  experiments  :  — 

EXPERIMENTS   WITH   CULTURES   OF   B.  TYPHOSUS  AND  B.  COLI  COMMUNIS. 


PERCENTAGE  OF  MORTALITY. 

CULTURE  USED. 

ANIMALS. 

Inoculated 

Control 

Animals. 

Animals. 

B.  typhosus  (A), 

Rats, 

75 

7 

" 

Guinea  Pigs, 

79 

0 

« 

Rabbits, 

100 

0 

B.  typhosus  (B), 

Guinea  Pigs, 

80 

0 

<« 

Rabbits, 

70 

0 

B.  coli  communis, 

Guinea  Pigs, 

83.3 

0 

It  is  held  at  the  present  time  by  the  best-informed  students 
along  this  line,  that  if  a  given  source  of  water  supply  is  exposed  to 
constant  or  even  occasional  sewage  contamination,  and  that  such 
sewage  contains  the  dejecta  from  typhoid  patients  in  hospitals  and 
residences,  it  is  not  necessary  to  have  direct  proof  of  the  presence 
of  the  typhoid  bacillus  in  such  water  to  justify  its  condemnation. 

*  "On  Putrid  Gases  as  Predisposing  Causes  of  Typhoid  Infection,"  by  Dr.  Giuseppe 
Alessi,  Journal  of  the  Sanitary  Institute,  London,  January,  1896,  p.  505. 


62  THE  PURIFICATION  OF   WATER. 

The  circumstantial  evidence  that  the  organism  'is  in  such  water 
is  sufficient,  and  the  failure  to  find  the  bacillus  upon  test  should 
not  be  taken  as  evidence  of  its  non-existence. 

The  typhoid  bacillus,  originally  isolated  and  described  by 
Eberth,  has  been  made  the  subject  of  careful  study  by  Koch, 
Gaffky,  Frankell,  and  Simmonds,  and  latterly  by  Joseph  Sanarelli, 
of  the  Pasteur  Institute,  Paris.  Several  papers  by  Sanarelli  have 
appeared  in  discussion  of  the  organism,  —  its  connection  with  the 
etiology  of  typhoid  fever,  the  symptoms  and  lesions  produced,  and 
results  of  inoculation  in  the  lower  animals, — of  which  the  more 
important  deductions  and  opinions  are  worthy  of  mention. 

The  so-called  typhotoxin,  described  by  Brieger  as  a  product  of 
the  vital  activity  of  the  Eberth  bacillus,  is  considered  by  Sanarelli 
only  as  an  ordinary  product  of  decomposition,  arising  from  the 
changes  which  occur  in  the  albuminoid  substances  of  the  culture 
media,  or  to  bacterial  poisons  previously  existing  in  the  culture. 

Of  the  Stas-Otto  method  by  which  typhotoxin  is  obtained  it 
has  been  said  :  *  — 

"  However,  the  method  is  not  free  from  criticism.  The  great  number  of 
chemical  manipulations  to  which  the  organic  matter  is  subjected  is  liable  to 
lead  to  the  formation  of  some  basic  substances,  and  to  the  destruction  of 
others.  One  is  justified  in  considering  the  isolated  base  as  preexisting  in  the 
original  material,  only  when  it  produces  symptoms  identical  with  those  caused 
by  the  substance  from  which  it  is  extracted." 

Vaughan  and  Novy,  however,  assume  that  Brieger  has  actually 
isolated  the  poisonous  product  of  the  typhoid  bacillus  ;  while  Sana- 
relli rejects  typhotoxin,  so-called,  as  a  product  of  the  Eberth  germ. 
Sanarelli  calls  attention  to  the  fact  that  "  recent  investigators  have 
shown  that  evaporation  of  the  albuminous  liquids  in  the  presence 
of  hydrochloric  acid  and  their  subsequent  extraction  with  alcohol 
is  alone  sufficient  to  produce  bodies  considered  by  Brieger  as  pto- 
maines, and  the  typhotoxin  does  not  produce  a  morbid  state  com- 
parable with  that  of  typhoid  fever,"  and  concludes  that  all  attempts 
to  ascertain  the  chemical  nature  of  the  poison  produced  by  the 
•typhoid  bacillus  are  failures. 

*  Ptomaines  and  Leucomaines,  by  Vaughan  and  Novy,  Philadelphia,  1891,  p.  170. 


THE    TYPHOID  BACILLUS  AND    TYPHOID   FEVER.  63 

Sanarelli  argues  that  no  matter  by  what  channel  the  typhoid 
bacillus  enters  the  system,  its  seat  of  operation  is  not  the  small 
intestine  (Peyers  glands),  as  heretofore  supposed,  but  the  spleen. 
Here  it  grows  and  elaborates  the  toxin  which  is  taken  into  the  cir- 
culation, and  produces  certain  local  effects  which  are  characteristic 
of  typhoid  fever.  He  holds  that  the  toxic  product  of  the  growth 
of  b.  typJwsus  in  the  spleen,  when  taken  into  the  circulation,  para- 
lyzes the  walls  of  the  intestine,  and  destroys  its  powers  of  resistance 
to  the  action  of  b.  coli  communis,  and  that  all  local  effect  in  the 
ileum  is  to  be  charged  to  the  latter  organism,  and  not,  as  has  been 
generally  supposed,  to  the  action  of  b.  typhosus  on  the  mucosa  and 
vessels  of  the  intestine. 

He  maintains  that  all  local  symptoms  of  typhoid  fever  are  like 
the  symptoms  in  the  ileum,  altogether  due  to  the  toxic  properties 
imparted  to  the  circulation  by  the  growth  and  development  of  b. 
typhosus  in  the  spleen.  He  claims  that  the  typhoid  bacillus  has 
never  been  isolated  from  the  dejecta,  nor  from  the  anatomical 
changes  in  the  intestine,  and  argues  that  if  typhoid  fever  has  its 
beginning  and  end  in  the  digestive  tract,  why  do  we  not  find  the 
b.  typhosus  there  from  the  very  beginning,  before  the  symptoms 
characteristic  of  the  disease  are  noticed.  The  diarrhea,  he  insists, 
is  maintained  and  aggravated  by  b.  coli  commnnis.  This  remark- 
able series  of  papers  contains  the  following  conclusions  :  — 

"  The  extraordinary  multiplication  of  the  colon  bacillus,  and  its  tendency 
to  destroy  all  other  bacteria  and  become  the  sole  representative  of  the  intesti- 
nal species,  are  the  results  of  an  active  biologic  work,  incessant  and  complex. 
.  .  .  When  the  poison  (elaborated  by  b.  typhosus}  has  attained  the  extreme 
limit  of  its  tolerance  by  the  subject,  the  fever  ceases,  and  collapse  ends  the 
scene.  It  is  this  period  of  collapse  which  we  reproduce  experimentally  on 
animals.  In  them  the  typhoid  virus  permeates  the  system,  and  manifests  its 
effects  too  rapidly  to  give  it  time  to  react  by  means  of  fever  during  the  early 
stages  of  intoxication.  If  the  bacillus  of  Eberth  could  produce  its  toxin  in  the 
human  system  as  rapidly  as  the  cholera  spirilla  do  theirs,  typhoid  fever  would 
be  like  cholera,  —  a  disease  short  of  duration  and  without  fever." 

According  to  Sanarelli,  by  reason  of  their  lower  powers  of 
resistance,  the  action  of  b.  typhosus  on  the  lower  animals  is  too 
rapid  to  produce  the  train  of  effects  which  are  recorded  of  this 
disease  in  man. 


64  THE   PURIFICATION  OF   WATER. 

To  the  medical  practitioner  these  conclusions  of  Sanarelli,  if 
confirmed  by  further  investigation,  should  possess  great  value, 
and  be  an  aid  to  him  in  revising  his  methods  of  treatment  of 
typhoid  fever.  To  the  sanitarian  they  also  possess  interest,  as 
showing  the  manner  in  which  a  certain  bacterium  (b.  coli  corn- 
munis),  always  in  the  human  intestine,  and  frequently  found  in 
sewage -polluted  waters,  may  indirectly  be  endowed  with  extra 
pathogenic  powers,  and  sustain  a  relationship  to  typhoid  fever 
not  heretofore  suspected. 

The  typical  typhoid  bacillus,  the  bacillus  of  Eberth,  is  found  in 
the  spleen,  and  occasionally  in  some  other  organs  of  one  who  has 
died  during  the  early  stages  of  typhoid  fever.  This  organism,  as 
is  well  known,  has  morphological  and  biological  characteristics 
unlike  the  colon  bacillus  ;  and  considering  the  well-founded  doubts 
of  the  several  alleged  discoveries  of  the  true  typhoid  germ  in  water 
supplies,  while  many  investigators  have  isolated  the  colon  bacillus 
from  this  source,  some  strength  is  imparted  to  Professor  Lankes- 
ter's  assumption  that  b.  typhosus  may  be  an  exacerbated  form  of 
b.  coli  communis. 

It  has  been  stated  that  Malvoz  of  Liege,  by  successive  culti- 
vations of  b.  coli  commtmis  in  a  slightly  acid  bouillon,  produced  a 
species  showing  the  characteristics  of  Eberth's  bacillus. 

The  influence  of  environment  on  species  is  well  known ;  and  may 
it  be  possible  that  b.  coli  communis,  when  taken  into  the  human 
system  through  the  medium  of  drinking-water,  in  certain  persons 
finds  there  the  conditions  favorable  to  its  development  into  what 
we  know  as  b.  typhosus  ?  Certain  schools  *  refuse  to  recognize  a 
difference  between  these  two  organisms,  although  they  do  not  go 
so  far  as  Professor  Lankester,  and  assume  that  one  may  become 
the  other.  They  regard  the  two  bacilli  as  different  forms  of  the 
same  species,  and  treat  b.  coli  communis  as  a  cause  of  typhoid  fever. 

Dr.  Jordan,!  of  the  University  of  Chicago,  in  a  very  able  paper 
on  the  characteristics  of  the  typhoid  bacillus,  says  :  - 

*  Sanarelli :  Annales  de  r Institute  Pasteur,  Nov.  25,  1892. 

t   The  Identification  of  the  Typhoid  Fever  Bacillus,  by  Edwin  O.  Jordan,  Ph.D.,  Chicago, 


THE    TYPHOID  BACILLUS  AND    TYPHOID  FEVER.  65 

"  While  the  close  similarity  of  the  colon  bacillus  anft  the  typhoid  bacillus 
is  necessarily  recognized  'by  every  one,  and  while  it  is  admitted  that  there  is  no 
single  criterion  that  absolutely  distinguishes  the  latter  from  all  the  perplexing 
'varieties'  and  'related  forms,'  it  is  nevertheless  maintained  by  many  that  the 
sum  total  of  the  morphological  and  physiological  characters  presents  a  true 
and  unmistakable  picture  of  the  specific  organism  of  typhoid  fever.  These 
investigators  hold  that,  although  the  varieties  may  approach  more  or  less 
closely  to  the  typical  typhoid  germ,  they  may  always  be  distinguished  from  it 
by  at  least  some  one  character  which  is  not  shared  by  the  genuine  typhoid 
organism." 

In  his  summary  on  the  existing  information  upon  the  differen- 
tiation of  the  typhoid  organism  from  the  colon  bacillus  and  allied 
germs,  among  other  conclusions  he  states  :  — 

(1)  "  There  is  usually  found  in  the  spleen  and  other  organs  of  an  indi- 
vidual dying  with  typhoid  fever,  a  bacillus  which  possesses  certain  definite 
morphological  and  physiological  characters.  .  .  . 

(5)  "The  cases  of  alleged  conversion  of  one  'species'  or  'variety'  (b.  coli 
communis}  into  another  (b.  typhosus}  do  not  carry  conviction,  and  are  suscept- 
ible of  other  interpretations  than  those  advanced  regarding  them." 

So  far  as  protection  to  our  public  water  supplies  is  concerned, 
this  diversity  of  opinion  on  the  typhoid  bacillus  as  an  independ- 
ent organism  can  have  little  weight.  The  means  adopted  for  the 
exclusion  of  b.  typhosus  from  our  drinking-waters  will  also  exclude 
the  colon  bacillus.  At  least,  it  is  not  now  known  that  a  filter 
properly  constructed  and  operated  will  not  be  equally  effective  in 
restraining  the  passage  of  either  germ  ;  and  methods  of  sterilization 
such  as  are  in  use  on  sea-going  vessels  are  bound  to  eliminate  both 
organisms  from  our  drinking-waters.  There  is,  however,  this  dif- 
ference to  be  considered  between  the  generally  accepted  theory 
of  the  transmission  of  the  typhoid  bacillus  from  the  sick  to  the 
well  through  the  direct  sewage  pollution  of  drinking-waters,  and 
the  theory  of  Professor  Lankester  of  the  colon  bacillus  under 
proper  conditions  becoming  the  typhoid  bacillus,  that  if  the  latter 
should  be  substantiated,  the  exposure  to  typhoid  fever  from  water 
sources  is  much  greater  than  has  generally  been  supposed  ;  and  no 
surface  water  supply,  the  drainage  area  of  which  is  inhabited  by 
domestic  animals,  can  be  regarded  as  proof  against  a  possible  con- 
tamination by  b.  coli  communis. 


66 


THE   PURIFICATION  OF   WATER. 


The  percentage  of  mortality  from  typhoid  fever  is  variously 
stated  in  text-books,  and  some  statistics  from  the  later  experience 
of  American  cities  with  this  disease  are  given  in  the  table  which 
follows  :  — 

TYPHOID  FEVER  MORTALITY. 


CITY. 

PERIOD  TAKEN. 

CASES 
REPORTED. 

DEATHS. 

PERCENTAGE 

OF 

MORTALITY. 

Lowell,  Mass., 

Sept.,  1890,  to  Jan.     1891, 

550 

89 

16.2 

«           « 

Nov.,  1892,  to  Feb.,  1893, 

141 

30 

21.3 

Lawrence,  Mass., 

Nov.,  1892,  to  Feb.,  1893, 

141 

28 

20.0 

Springfield,  Mass., 

July,   1892,  to  Sept.,  1892, 

155 

32 

20.6 

St.  Louis,  Mo., 

April,  1892,  to  Mar.,  1893, 

3,624 

514 

14.2 

«<           «( 

Aug.,  1892,  to  Jan.,  1893, 

3,455 

453 

13.1 

Pittsburg,  Pa., 

1891, 

1,047 

248 

23.7 

«           « 

1892, 

1,145 

256 

22.4 

<(           « 

1893, 

2,398 

294 

12.3 

Schenectady,  N.Y., 

July,  1890,  to  April,  1891, 

300 

70 

23.3 

Cincinnati  Hospital, 

1891, 

85 

11 

13.0 

«           « 

1892, 

59 

7 

12.0 

«           <t 

1893, 

108 

4 

3.7 

«           « 

1894, 

117 

14 

12.0 

«           « 

1895, 

98 

10 

10.2 

It  is  a  fact  well  known  to  physicians  and  investigators,  that 
typhoid  fever  is  everywhere  a  disease  which  sets  in  late  in  sum- 
mer or  early  in  autumn,  and  continues  above  the  normal  rate 
until  midwinter,  after  which  it  usually  shows  a  decline,  falling  to 
the  lowest  case  and  death  rates  during  the  months  of  spring.  The 
theory  of  Pettenkofer  and  others  of  the  Munich  school,*  that  the 
disease  rises  and  falls  in  intensity  as  the  level  of  the  ground  water 
falls  and  rises,  is  partly  supported  by  the  usual  seasonal  distribu- 
tion of  typhoid. 

In  spring  the  level  of  ground  water  is  high,  and  the  typhoid 
rates  low.  In  the  autumn  the  level  of  the  ground  water  is  low, 
while  the  typhoid  rates  are  high  ;  but  so  many  proofs  are  at  hand 
showing  high  typhoid  rates  with  high  levels  of  ground  water,  and 
low  typhoid  rates  accompanied  by  low  levels  of  ground  water,  that 
the  Pettenkofer  theory  of  a  connection  between  the  level  of  the 

*  Cholera,  by  Dr.  Max  Von  Pettenkofer,  translated  by  Dr.  T.  M.  Hime,  London,  1893 
(chart  facing  title-page). 


THE    TYPHOID  BACILLUS  AND    TYPHOID  FEVER.  67 

ground  water  and  typhoid  fever  is  not  of  general  application,  and 
cannot  point  to  a  probable  general  cause  for  this  disease  in  the 
lowering  of  the  level  of  ground  water. 

Another  theory  of  the  cause  of  the  rise  in  the  typhoid  fever 
rates  during  autumn  is  based  on  the  assumption  that  the  early 
rains  carry  into  the  streams  and  lakes  which  constitute  so  many 
sources  of  water  supply,  sewage  and  offal  which  has  accumulated 
upon  the  ground  and  along  the  banks  of  streams  during  the  period 
of  drought.  Opposed  to  this  theory,  however,  is  the  almost  uni- 
form condition  that  the  typhoid  rates  begin  to  rise  before  the  fall 
rains  occur.  Indeed,  the  maximum  rate  is  often  reached  in  the 
autumn,  before  rains  have  fallen  sufficient  in  volume  to  swell  the 
streams,  and  wash  organic  refuse  from  the  banks. 

Dr.  Woodhead  *  has  indirectly  suggested  a  theory  which,  prop- 
erly expanded,  seems  to  furnish  a  good  reason  for  the  seasonal 
influence  on  the  typhoid  rate  ;  viz.,  that  the  development  of  the 
typhoid  bacillus  in  water  will  depend  upon  the  temperature  of 
the  water  in  which  it  is  migrating,  low  temperature  discoura- 
ging the  growth  of  the  bacillus,  while  high  temperature  favors  it. 
During  the  early  autumn  the  lakes  and  rivers  are  at  the  highest 
temperature,  which  continues  with  slow  diminution  (in  the  tem- 
perate zone)  well  into  the  winter.  During  this  period  of  high 
natural  water  temperature,  typhoid  fever  usually  rises  to  its  great- 
est intensity  for  the  year ;  and  when  the  temperature  of  the  water 
naturally  declines,  and  approaches  its  lowest  point  after  midwinter, 
the  typhoid  rates  also  subside  and  reach  their  minimum. 

This  theory  of  the  rise  and  fall  of  typhoid  rates  does  not  depend 
upon  floods  nor  upon  the  level  of  the  ground  water,  and  is  entirely 
consistent  with  the  information  upon  the  growth  of  the  typhoid 
bacillus  in  the  human  body  and  in  the  usual  culture  media. 

The  influence  of  proper  preventive  measures  on  typhoid  fever 
is  shown  by  the  experience  of  Vienna  and  Munich. 

Professor  Von  Zeimssen  f  of  the  latter  city  a  few  years  ago 
stated  "  that  the  reduction  in  the  cases  in  the  hospital  had  almost 

*  Royal  Commission  on  Metropolitan  Water  Supply,  London,  1893,  Minutes  of  Evi- 
dence, p.  506. 

t  On  Typhoid  Fever  in  Baltimore,  by  Dr.  William  Osier,  1892. 


68  THE  PURIFICATION  OF   WATER. 

changed  the  character  of  the  service,  and  they  had  scarcely  patients 
enough  to  illustrate  the  disease  in  the  clinical  courses."  Dr.  Osier 
is  disposed  to  credit  this  reduction  in  the  typhoid  rates  in  these 
cities  to  improved  sewerage,  when  it  is  really  due  largely  to  the 
remarkable  improvements  in  their  public  water  supplies,  Munich 
having  abandoned  its  old  sources  in  wells  and  the  River  Isar  for 
mountain  springs  in  the  Mangfall  valley,  and  Vienna  having  aban- 
doned its  wells  and  the  Danube  for  the  Schneeberg  springs  in  the 
Alps. 

Improvements  in  sewerage  should  reduce  the  susceptibility  of  a 
people  to  typhoid  infection,  but  the  cause  is  removed  when  pure 
water  is  substituted  for  polluted  water. 

The  channels  of  typhoid  fever  infection  for  a  large  city  are 
clearly  indicated  in  a  recent  paper  by  Dr.  J.  J.  Reincke,  On  the 
Epidemiology  of  Typhoid  Fever  in  Hamburg  and  Altona  ;  *  and  as 
applicable  especially  to  Hamburg  before  filtration  of  the  Elbe  water 
was  adopted,  he  mentions  :  — 

(1)  Importation  of  typhoid  by  way  of  the  sea  and  the  upper  Elbe,  and 
infection  of  the  water  of  the  river  in  front  of  the  city  by  travelers. 

(2)  Infection  of  the  water  of  the  Elbe  by  patients  in  the  city,  whose  dis- 
infected dejecta  is  carried  by  the  sewage  into  the  river. 

(3)  Infection  of  the  Elbe  water  from  people  on  the  ships,  city  dock  labor- 
ers, and  bathers. 

(4)  Infection  by  means  of  food  which  had  come  in  contact  with  the  Elbe 
water. 

(5)  Infection  through  the  unfiltered  Elbe  water  distributed  to  the  people 
prior  to  May,  1893. 

(6)  Infection  by  patients  and  food  brought  into  Hamburg  from  neighbor- 
ing places. 

(7)  Secondary  infection  within  the  city  by  direct  transmission,  or  infection 
of  food  and  wells.    [Causes  which  he  holds  were  peculiarly  numerous  and  effec- 
tive in  the  second  half  of  the  great  epidemics.] 

Concerning  the  seasonal  distribution  of  typhoid,  he  shows  how 
the  number  of  cases  increase  in  autumn  and  decline  towards  spring. 
He  points  to  the  fact  that  in  Germany  the  years  1857,  1865,  and 
the  early  70's  were  years  of  high  typhoid  fever  rates,  and  the  years 
of  1860  and  1867  were  years  of  phenomenally  low  typhoid  fever 

*  Hamburg,  1896. 


THE    TYPHOID   BACILLUS  AND    TYPHOID  FEVER.  69 

rates  ;  and  suggests  that  "  there  must  be  certain  'influences  at  work 
(here)  that  are  more  far-reaching  than  the  predisposing  causes." 

He  mentions  conditions  heretofore  remarked,  that  the  epi- 
demics of  typhoid  which  originate  in  the  autumn  have  a  gradual 
decline,  while  epidemics  which  originate  during  the  late  winter  or 
early  spring  months  show  a  sharp  rise  and  fall  of  intensity  and  a 
sudden  disappearance.  Seasons  of  drought  with  low  levels  of  ground 
water  he  considers  as  favoring  high  typhoid  rates,  while  wet  sea- 
sons and  high  ground  water  levels  he  regards  as  unfavorable.  Dur- 
ing dry  seasons  there  is  greater  body  heat  with  more  thirst,  and  a 
larger  consumpion  of  water  for  drinking  and  bathing  purposes, 
which  increases  the  liability  to  infection. 

Dr.  Reincke  combats  Pettenkofer's  theory  of  the  cause  of 
typhoid  fever,  while  agreeing  with  him  that  the  proper  prophy- 
laxis for  the  disease  is  to  be  found  in  high  quality  of  public  water 
supplies  and  efficient  sewerage  and  drainage.  The  very  signifi- 
cant statement  is  made,  that  if  typhoid  fever  epidemics  are  pre- 
vented in  the  cities  there  will  be  none  in  the  country,  and  as  a 
consequence  there  can  be  no  reimportation  of  cases  into  the  cities. 

The  author,  after  careful  investigation,  reached  the  conclusion 
several  years  ago  that  the  sewage-polluted  waters  of  the  cities  were 
largely  responsible  for  typhoid  fever  in  the  country  districts,  and 
agrees  with  Dr.  Reincke  that  the  typhoid  rates  of  any  city  is  a 
measure  of  the  efficiency  of  its  works  of  sanitation. 

Speaking  of  Hamburg,  he  says  "that  the  present  favorable 
and  heretofore  unattainable  status  of  typhoid  fever  is  to  be  largely 
credited  to  the  filtered  water  supply,  as  indicated  by  the  fact  that 
this  disease  has  not  diminished  among  the  people  on  the  vessels 
arriving  at  the  port." 


70  THE  PURIFICATION  OF   WATER. 


CHAPTER    V. 

CLASSIFICATION    OF    CITIES    BY   TYPHOID   FEVER 
STATISTICS. 

IT  has  been -held  (and  correctly  in  the  author's  opinion)  that 
the  best  test  of  the  quality  of  a  city  water  supply  was  the  typhoid 
fever  rates  of  that  city.  Thus  a  city  with  water  of  high  quality 
should  show  low  typhoid  rates,  and  a  city  with  water  of  known 
sewage  pollution  should  show  high  typhoid  rates.  The  final  test 
of  all  public  water  supplies  is  the  influence  of  these  on  the  health 
of  the  consumers ;  and  in  order  to  institute  a  comparison  of  cities 
upon  the  basis  of  quality  of  water  supply,  the  author  proposed,  in  a 
lecture  recently  delivered  before  the  faculty  and  students  of  the 
University  of  Illinois,*  to  classify  the  larger  cities  of  the  world, 
embraced  within  the  scope  of  modern  health  statistics,  upon  their 
typhoid  fever  death  rates. 

Thus  cities  of  the  first  class  must  show  a  death  rate  from 
typhoid  fever  of  not  more  than  10  per  100,000  of  population 
living. 

Cities  of  the  second  class  must  show  a  rate  not  higher  than  20 
per  100,000  of  population  living. 

Cities  of  the  third  class  must  show  a  rate  not  higher  than  30 
per  100,000  of  population  living,  and  in  like  manner  by  tens  until 
the  sixth  class  was  reached.  All  cities  having  a  typhoid  death  rate 
in  excess  of  60  per  100,000  of  population  living  are  grouped  in 
the  seventh  class.  The  classification  is  made  upon  the  average 
rates  for  the  years  1890  to  1896,  inclusive,  for  the  principal  cities 
of  the  United  States,  Canada,  and  Europe,  including  two  cities  in 
Egypt  and  two  cities  in  Australia.  The  statistics  from  which  the 
classification  is  made  will  be  found  in  the  table  of  Typhoid  Fever 
Statistics,  Appendix  A. 

*   Water  Supply  of  Cities,  Champaign,  111.,  189G. 


CLASSIFICA  riON  OF  CITIES  B  Y  TYPHOID  FE  VER  STA  TISTICS.     71 


CLASS    I.  — CONTAINING  ALL   CITIES  SHOWING  A   TYPHOID   FEVER   DEATH 
RATE   OF   1O  OR    LESS   PER   1OO.OOO   OF  POPULATION    LIVING. 

CLASS   I. 


CITY. 

SOURCE  OF  WATER  SUPPLY. 

POPULATION. 

TYPHOID 
FEVER 
DEATH 
RATE. 

Hague, 

From  sand  dunes, 

187,545 

4.7 

Rotterdam, 

Filtered  water  from  River  Maas, 

276.338 

5.7 

Munich, 

Spring  water  from  Mangfall  Valley, 

406,000 

6.0 

Dresden, 

Filter  wells  and  gallery  by  River  Elbe, 

342,340 

6.2 

Vienna, 

Springs  in  the  Schneeberg, 

1,526,623 

6.6 

Berlin, 

Filtered  water   from   River   Spree   and 

Lake  Tegel, 

1,695,313 

7.1 

Copenhagen, 

Filtered  from  wells  and  springs, 

333,714 

9.0 

CLASS   II. 


CITY. 

SOURCE  OF  WATER  SUPPLY. 

POPULATION. 

TYPHOID 
FEVER 
DEATH 
RATE. 

Christiania, 

182,856 

10.6 

Breslau, 

Filtered  from  River  Oder, 

377,062 

10.7 

Amsterdam, 

Haarlem  dunes,  and  River  Vecht,  filtered, 

489,496 

11.9 

Stockholm, 

Lake  and  well  water, 

267,100 

12.3 

London, 

Kent  wells,  and  filtered  water  from  Riv- 

ers Thames  and  Lea, 

4,421,955 

14.4 

Trieste, 

161,866 

14.7 

Edinburgh, 

Impounded  and  filtered  water  from  Pent- 

land  Hills, 

276,514 

16.4 

Hamburg, 

Filtered  water  from  River  Elbe, 

625,552 

17.7 

Brooklyn, 

Impounded  water,  and  open  and  driven 

wells, 

1,140,000 

18.0 

New  York, 

Impounded  water  from  Croton  and  Bronx 

Rivers, 

1,934,077 

19.3 

CLASS    III. 


TYPHOID 

FEVER 

CITY. 

SOURCE  OF  WATER  SUPPLY. 

POPULATION. 

DEATH 

RATE. 

Paris, 

Rivers  Seine,  Marne,  and  Vanne,  Ourcq 

Canal,  artesian  wells,  and  springs, 

2,511,629 

22.0 

Sydney,  N.S.W. 

Impounded  water  from  Upper  Nepean 

River, 

423,600 

22.0 

Glasgow, 

Loch  Katrine, 

705,052 

23.0 

Buda-Pest, 

Ground  water  from  wells, 

579,275 

23.0 

72 


THE   PURIFICATION  OF   WATER. 

CL AS  S  III.  —  Continued. 


CITY. 

SOURCE  OF  WATER  SUPPLY. 

POPULATION. 

TYPHOID 
FEVER 
DEATH 
RATE. 

Brussels, 

518,387 

23.5 

Manchester, 

Lake  Thirlmere, 

530,000 

25.7 

New  Orleans, 

Drinking-water  from  tanks  and  cisterns, 

275,000 

25.9 

Altona, 

Filtered  from  River  Elbe, 

148,934 

26.8 

Davenport, 

Mechanical  filter,  Mississippi  River, 

35,000 

28.6 

Venice, 

Impounded  water, 

163,254 

28.7 

Milwaukee, 

Lake  Michigan, 

257,500 

29.3 

Brisbane,  Qu. 

93,657 

29.7 

CLASS   IV. 


DATE. 

SOURCE  OF  WATER  SUPPLY. 

POPULATION. 

TYPHOID 
FEVER 
DEATH 
RATE. 

Detroit, 

Detroit  River, 

279,000 

30.1 

Boston, 

Lake  Cochituate  and  Sudbury  River, 

508,694 

32.6 

Buffalo,  ' 

Niagara  River,  at  head, 

350,000 

34.3 

Turin, 

344,203 

34.3 

Rome, 

Fontanadi  Trevi,  Aqua  Felice,  and  Paoli, 

473,296 

35.7 

Dayton, 

Driven  wells, 

85,000 

36.0 

Liverpool, 

Lake  Vyrnwy  (Wales), 

632,000 

36.3 

Providence, 

Pawtuxet  River, 

150,000 

36.4 

Covington, 

Ohio  River, 

50,000 

36.6 

Newark, 

Impounded    water    from     Pequannock 

River, 

230,000 

38.1 

San  Francisco, 

Impounded  water  from  mountain  springs, 

330,000 

38.4  v, 

St.  Louis, 

Mississippi  River, 

570,000 

39.0 

CLASS  V. 


CITY. 

SOURCE  OF  WATER  SUPPLY. 

POPULATION. 

TYPHOID 
FEVER 
DEATH 
RATE. 

Prague, 

364,632 

41.4 

Baltimore, 

Gunpowder  River,  Lake  Roland, 

507,398 

43.6 

Nashville, 

Filter  gallery,  Cumberland  River, 

87,754 

44.7 

Philadelphia, 

Schuylkill  and  Delaware  Rivers, 

1,188,793 

45.0 

Cleveland, 

Lake  Erie, 

330,279 

46.4 

Denver, 

South  Platte  River  and  Marston  Lake, 

150,000 

47.2 

Toronto, 

Lake  Ontario, 

196,666 

49.3 

Cincinnati, 

Ohio  River, 

341,000 

49.4 

CLASSIFICA  TION  OF  CITIES  B  Y  TYPHOID  FE  VER  STA  TISTICS.     73 


CLASS  VI. 


CITY. 

SOURCE  OF  WATER  SUPPLY. 

POPULATION. 

TYPHOID 
FEVER 
DEATH 
RATE. 

Dublin, 

River  Vartry,  impounded  water,  filtered, 

349,594 

52.3 

Quincy, 

Mechanical  filters,  Mississippi  River, 

42,000 

53.6 

Moscow, 

Mytisch  springs  and  ponds,  Moscow  and 

Yanza  Rivers, 

753,469 

54.4 

Newport, 

Ohio  River, 

30,000 

57.7 

Knoxville 

Mechanical  filters,  Tennessee  River, 

45,000 

59.7 

(with  suburbs), 

Milan, 

441,948 

59.7 

CLASS   VII. 


CITY. 

SOURCE  OF  WATER  SUPPLY. 

POPULATION. 

TYPHOID 
FEVER 
DEATH 
RATE. 

Indianapolis, 

Driven  wells,  and  White  River, 

165,000 

64.5 

Chattanooga, 

Mechanical  filters,  Tennessee  River, 

.  40,000 

68.2 

Washington, 

Potomac  River, 

278,150 

71.1 

Chicago, 

Lake  Michigan, 

1,619,226 

71.2 

Jersey  City, 

Passaic  and  Pequannock  Rivers, 

187,098 

72.5 

Louisville, 

Ohio  River, 

211,100 

74.3 

Lawrence,  Mass., 

Filtered  water  fromMerrimac  River, 

55,000 

75.3 

St.  Petersburg, 

Filtered  water  from  River  Neva, 

954,400 

77.2 

Lowell,  Mass., 

Merrimac  River,  driven  wells, 

85,700 

77.6 

Pittsburgh, 

Alleghany  River, 

280,000 

84.2 

Atlanta, 

Mechanical      filters,    Chattanooga 

River, 

110,000 

85.1 

Alexandria,  Egypt, 

River  Nile,  by  canal, 

231,396 

143.4 

Cairo,  Egypt, 

River  Nile,  by  canal, 

374,838 

168.3 

CLASSIFICATION    BASED   ON   LAST  YEAR   REPORTED  (1896). 
CLASS  I. 


CITY. 

POPULATION. 

RATE. 

CITY. 

POPULATION. 

RATE. 

Amsterdam, 

489,496 

3 

Vienna, 

1,526,623 

5 

Munich, 

406,000 

3 

Hamburg, 

625,552 

6 

Hague, 

187,545 

4 

Stockholm, 

267,100 

6 

Dresden, 

342,340 

4 

Copenhagen, 

333,714 

7 

Berlin, 

1,695,313 

5 

Breslau, 

377,062 

8 

74 


THE   PURIFICATION  OF   WATER. 


CLASS   II. 


CITY. 

POPULATION. 

RATE. 

CITY. 

POPULATION. 

RATE. 

Paris, 

2,511,629 

11 

Lawrence, 

55,000 

15 

Rotterdam, 

276,338 

12 

Edinburgh, 

276,514 

16 

Altona, 

148,934 

13 

New  York, 

1,934,077 

16 

Trieste, 

161,886 

13 

Milwaukee, 

257,500 

18 

London, 

4,421,955 

14 

Brussels, 

518,387 

18 

Brooklyn, 

1,140,000 

15 

St.  Louis, 

570,000 

19 

CLASS   III. 


CITY. 

POPULATION. 

RATE. 

CITY. 

POPULATION. 

RATE. 

Buffalo, 

350,000 

20 

Dayton, 

85,000 

25 

Detroit, 

279,000 

20 

Quincy, 

42,000 

26 

Davenport, 

35,000 

20 

Venice, 

163,254 

27 

Sydney, 

423,600 

20 

Providence, 

150,000 

27 

Newark,  N.J., 

230,000 

21 

Rome, 

473,296 

27 

Glasgow, 

705,052 

23 

Prague, 

364,632 

28 

Manchester, 

530,000 

23 

Toronto, 

196,666 

28.5 

Turin,- 

344,203 

24 

Buda-Pest, 

579,275 

29 

CLASS   IV. 


CITY. 

POPULATION. 

RATE. 

CITY. 

POPULATION. 

RATE. 

Chattanooga, 

40,000 

30 

Liverpool, 

632,000 

•32 

San  Francisco, 

330,000 

31 

Christiania, 

182,856 

33 

Boston, 

508,694 

32 

New  Orleans, 

275,000 

33 

Covington, 

50,000 

32 

Philadelphia, 

1,188,793 

34 

Knoxville, 

37,000 

32 

Baltimore, 

507,398 

37 

(without  suburbs), 

CLASS  V. 


CITY. 

POPULATION. 

RATE. 

CITY. 

POPULATION. 

RATE. 

Indianapolis, 

165,000 

41 

Dublin, 

349,594 

45 

Lowell,  Mass., 

85,700 

42 

Chicago, 

1,619,226 

46 

Cleveland, 

330,279 

43 

Moscow, 

753,469 

46 

Louisville, 

211,100 

45 

Cincinnati, 

341,000 

48 

CLASS  VI. 


CITY. 

POPULATION. 

RATE. 

Washington, 
Nashville, 
Milan, 

278,150 
87,754 
441,948 

51 
55 
55 

CLASSIFICA  TION  OF  CITIES  B  Y  TYPHOID  FE  VER  STA  TISTICS.     75 


CLASS  VII. 


CITY. 

POPULATION. 

RATE. 

CITY. 

POPULATION. 

RATE. 

Atlanta, 

110,000 

60 

Newport,  Ky., 

30,000 

63.0 

Brisbane, 

93,657 

60 

Alexandria, 

231,396 

89 

Pittsburg, 

280,000 

61 

Cairo, 

374,838 

141 

Denver, 

150,000 

61 

St.  Petersburg, 

954,400 

142 

Jersey  City, 

187,098 

61.5 

A  review  of  the  statistics  furnished  by  the  tables  reveals  some 
interesting  facts  :  — 

No  city  in  the  United  States  appears  in  the  first  class,  and  only 
two  cities  (Brooklyn  and  New  York)  appear  in  the  second  class. 
All  other  cities  in  these  two  classes  are  found  abroad. 

Considering  that  as  an  average  for  seven  years,  and  for  the  last 
year,  from  seven  to  ten  of  the  large  cities  of  the  world  fall  within 
the  limit  of  the  first  class,  it  is  painfully  evident  that  a  typhoid 
fever  death  rate  of  10  per  100,000  of  population  living  is  easy  of 
attainment  when  municipal  corporations  really  desire  to  bring  it 
about.  Few  people  realize  the  relative  standing  of  cities  in  the 
hygiene  of  their  public  water  supplies  ;  and  this  classification  will 
enable  a  comparison  to  be  made,  which  should  convince  even  the 
skeptical  that  in  the  matter  of  our  public  water  supplies  we  are  far 
behind  the  larger  cities  of  Europe. 

Referring  to  the  cities  of  the  first  and  second  class,  Rotterdam 
draws  its  water  supply  from  the  River  Maas,  one  of  the  mouths  of 
the  Rhine,  and  passes  it  through  sand  filters  before  it  is  delivered 
to  the  consumers.  Amsterdam*  and  The  Hague  draw  their  water 
supplies  from  the  sand  dunes,  and  afterwards  subject  it  to  careful 
filtration.  Vienna  and  Munich  depend  upon  water  from  large 
springs  at  high  elevation  in  the  Alps  ;  the  former  in  the  Schnee- 
berg,  65  miles  southwest  of  the  capital,  and  the  latter  in  the  Mang- 
fall  valley,  37  miles  from  the  city.  Dresden  is  supplied  from  an 
infiltration  well  on  the  banks  of  the  Elbe,  which,  according  to  Mr. 
B.  Salbach,f  intercepts  an  underground  flow  parallel  to  the  river. 

Berlin,  the  largest  city  in  the  first  class,  draws  its  water  from 


*  This  city  takes  a  portion  of  its  water  supply  from  the  River  Vecht. 
t    Transactions  American  Society  of  Civil  Engineers,  vol.  xxx.,  p.  293. 


76  THE   PURIFICATION  OF   WATER. 

two  sources,  —  the  Stralau  Works  from  Lake  Tegel,*  an  expansion 
of  the  River  Havel,  and  the  Frederickshagen  Works  from  Lake 
Miiggel,  an  arm  of  the  River  Spree.  At  both  stations  the  water 
is  subjected  to  sand  filtration  before  it  is  pumped  to  the  distribut- 
ing reservoirs  or  mains.  Some  of  the  most  conscientious  and  com- 
plete investigations  of  sand  filtration  have  been  conducted  with  the 
niters  of  these  works  by  Plagge,  Proskauer,  Piefke,  and  others. 

Either  spring  water  or  filtered  well  and  river  waters  constitute 
the  sources  for  the  cities  in  the  first  class. 

London  falls  in  the  second  class,  and  here  the  sources  of  supply 
are  the  Rivers  Thames  and  Lea,  and  wells  in  the  chalk  or  soft 
limestone.  The  enormous  consumption  of  water  by  this  city,  now 
quite  200,000,000  imperial  gallons  per  day,  compels  an  abstrac- 
tion at  times  of  quite  30  per  cent  of  the  whole  stream  flow  of  the 
Thames,  and  even  a  larger  proportion  of  the  Lea. 

The  watersheds  of  these  streams  are  heavily  populated  by  urban 
and  rural  communities  ;  and  in  spite  of  precautions  to  prevent  sew- 
age contamination  of  the  water,  there  is  no  doubt  that,  with  a  low 
stream  flow  and  small  dilution  of  sewage  effluents,  the  pollution  of 
the  raw  river  waters  at  times  is  very  great.  A  review  of  the  his- 
tory of  the  London  sand  filters  and  their  operation  further  suggests 
that  the  same  solicitude  for  water  quality  is  not  found  here  as  in 
some  of  the  Dutch  and  German  cities,  and  to  these  facts  may  be 
ascribed  the  higher  death  rates  from  typhoid  fever  in  London  than 
in  the  cities  grouped  in  the  first  class. 

The  natural  conditions  of  the  water  supplies  of  Edinburgh,  New 
York,  and  Brooklyn  are  in  some  respects  alike,  with  the  probability 
that  the  New  York  watershed  is  more  completely  protected  from 
manifest  sewage  pollution  than  the  watershed  of  Edinburgh  in  the 
Pentland  Hills.  Filtration  of  the  water  is  occasionally  resorted  to 
by  the  latter  city,  according  to  Mr.  J.  P.  Kirkwood,  mainly  to  cor- 
rect the  turbidity  ;  and  it  is  not  known  that  any  large  improvement 
has  taken  place  in  the  manner  of  operating  the  filters  of  late  years. 
The  hygiene  of  the  water  supply  of  Edinburgh  should  be  like  that 
of  New  York,  and  the  typhoid  fever  rates  support  this  view. 

*  The  works  at  Stralau  have  not  been  operated  for  several  years,  but  are  kept  in  reserve. 
All  water  is  now  supplied  from  the  Lake  Miiggel  Works. 


CLASSIFICA  TION  OF  CITIES  B  Y  TYPHOID  FE  VER  STA  TISTICS.     77 

Hamburg,  a  city  which  for  a  period  of  seven  years  falls  in  the 
second  class,  but  which  since  the  introduction  of  filtered  water  is 
found  in  the  first  class,  has  had  an  unique  experience.  Prior  to 
May,  1893  (the  spring  following  the  cholera  epidemic),  the  water 
was  drawn  from  the  Elbe,  and,  apart  from  a  limited  sedimentation 
in  reservoirs  of  small  capacity,  was  sent  to  the  consumers  with  no 
improvement  in  its  quality.  Since  the  date  mentioned  all  water 
has  been  filtered  under  the  supervision  of  Dr.  Dunbar,  director  of 
the  Hygienic  Institute,  and  Mr.  Rud  Schroder,  inspector  of  the 
Water- Works,  with  the  result  that  the  typhoid  rates  have  been  re- 
duced quite  73.5  per  cent.  No  other  change  has  been  made  in 
the  water  supply  than  its  filtration.  The  water  of  the  Elbe,  with 
its  sewage  pollution  from  all  sources  above  the  city,  is  used  now 
as  heretofore ;  but  none  of  it  goes  into  the  distributing  mains  until 
it  is  first  passed  through  an  elaborate  system  of  plain  sand  filters. 

Cities  which  depend  upon  water  supplies  from  sources  known 
to  be  sewage  polluted,  and  of  which  no  attempt  is  made  at  puri- 
fication, very  naturally  suffer  from  high  typhoid  rates ;  and  an 
examination  of  the  cities  in  classes  four  to  seven  shows  that  nearly 
all  of  them  are  in  our  own  country. 

The  classification  of  cities  for  the  last  year  of  report  (1896) 
enables  Hamburg,  Newark,  Jersey  City,  and  Lawrence  to  show 
what  has  been  accomplished  toward  reduction  of  the  typhoid  rates 
by  the  substitution  of  good  for  bad  water. 

With  reference  to  the  use  of  public  water  supplies  for  dietetic 
purposes,  in  cities  of  Europe,  the  author,  in  a  recent  lecture  upon 
the  hygiene  of  water,  published  in  the  Dietetic  and  Hygienic 
Gazette,  Philadelphia,  October,  1896,  says:  — 

"When  comparisons  are  made  of  the  typhoid  death  rates  of  cities  in 
Europe  with  cities  in  this  country,  the  claim  is  sometimes  urged  that  the 
people  of  Europe,  and  especially  of  Germany,  are  not  water  drinkers,  that 
beer  is  their  usual  beverage ;  and  upon  the  other  hand,  that  the  people  of  the 
United  States  are  not  beer  drinkers,  but  water  drinkers,  and  therefore  more 
exposed  to  water-carried  infections.  When  it  is  stated  that  *The  Hague  has 
a  typhoid  death  rate  of  5  per  100,000  of  population,  this,  according  to  some 
critics,  is  not  to  be  taken  as  an  evidence  of  the  high  quality  of  water  supplied 
to  the  city,  but  as  an  indication  that  the  people  of  The  Hague  generally  do 
not  drink  water,  and  depend  upon  beer  or  some  other  manufactured  beverage." 


78  THE  PURIFICATION  OF   WATER 

"  This  expression  of  doubt  by  some,  that  water  may  be  so  purified  by  artifi- 
cial means,  or  may  be  naturally  so  pure  as  to  largely  diminish  the  probability 
of  one  contracting  typhoid  fever  by  drinking  it,  suggests  inquiry  along  three 
lines :  — 

"1.  Is  the  water  supplied  to  certain  foreign  cities  such  as  to  reduce  the 
typhoid  fever  rates  or  inhibit  the  disease,  if  it  were  generally  used  as  a  bever- 
age ? 

"  2.  Is  the  water  generally  used  for  drinking  in  the  larger  cities  of  the 
United  States  such  as  to  be  the  probable  cause  of  our  high  typhoid  fever 
rates  ? 

"3.  Is  it  true  that  the  people  of  London,  Berlin,  Hamburg,  and  other 
European  cities  are  largely  beer  drinkers,  while  the  people  of  Boston,  New 
York,  Cincinnati,  and  other  American  cities  are  largely  water  drinkers? 

"  It  is  not  possible  to  answer  the  first  question  directly.  Despite  the  great 
chemical  and  bacterial  improvement  by  sedimentation  and  (or)  filtration  of 
certain  polluted  waters  like  that  of  the  Elbe  at  Hamburg,  and  the  Maas  at 
Rotterdam,  one  cannot  say  positively  that  such  waters,  even  after  treatment, 
will  not  contain  the  typhoid  bacillus,  or  be  the  carrier  of  infection  to  some ; 
and  we  are  compelled  to  measure  the  improvement  in  quality  of  such  waters 
by  their  influence  upon  the  health  of  the  people  who  use  them. 

"In  regard  to  the  quality  of  water  supplied  to  the  people  of  certain  cities 
in  Europe,  it  should  be  manifest,  if  this  was  not  to  be  used  as  a  drinking- 
water,  that  a  very  large  annual  expense  could  be  avoided  in  those  cities  by 
pumping  water  direct  into  the  reservoirs  or  street  mains  from  any  convenient 
source,  without  attempting  in  any  manner  an  improvement  in  its  quality  be- 
fore it  is  distributed  to  the  consumers. 

"  Water  of  high  hygienic  quality  is  not  required  for  the  sprinkling  of 
streets  and  lawns,  for  the  extinguishment  of  fires,  for  the  flushing  of  sanitary 
apparatus,  for  steam  boilers,  and  many  other  uses ;  and  if  the  water  is  not  to 
be  used  for  drinking  and  other  dietetic  purposes,  great  care  and  expense  in 
the  selection  of  a  source  of  supply,  or  in  efforts  at  improvement  of  the  quality 
of  water,  are  surely  wasted. 

"  Considering  that  over  ninety-eight  per  cent  of  the  consumption  of  water 
by  any  large  city  is  for  purposes  wholly  unaffected  by  its  hygienic  quality,  it 
would  seem  very  singular  indeed  that  a  city  like  Berlin  (for  instance)  should 
be  at  an  extra  expense  of  ten  dollars  per  million  gallons  to  fit  the  water  for 
drinking  purposes,  before  a  gallon  of  it  is  permitted  to  go  into  the  public  mains. 
This  great  cost  for  purification  of  the  water  from  Lakes  Miiggel  and  Tegel  is 
not  necessary  if  the  water  is  to  be  used  only  for  street  sprinkling  or  other  pur- 
poses apart  from  drinking  and  the  requirements  of  the  cuisine.  Moreover,  the 
water  from  Lake  Miiggel,  after  it  has  passed  through  the  filters  at  Fredericks- 
hagen,  as  we  have  shown,  is  chemically  and  bacterially  as  pure  as  many  nat- 
ural spring  or  deep  well  waters  which  are  known. to  be  altogether  safe  for 
drinking  purposes,  and  chemically  and  bacterially  pure  or  nearly  pure  waters 


CLASSIFICA  TION  OF  CITIES  B  Y  TYPHOID  FE  VETTSttTIS TICS.     79 


are  not  needed  for  any  of  the  many  uses  of  water,  excepting  for  drinking,  cook- 
ing, and  the  washing  of  uncooked  articles  of  diet.  No  one  would  propose  an 
elaborate  and  expensive  treatment  of  a  polluted  water  unless  some  portion  of 
it  was  to  be  drunk. 

"  The  water  of  the  River  Elbe,  when  it  reaches  Hamburg,  is  of  sufficient 
purity  for  all  ordinary  purposes  ;  but  the  most  modern  works  upon  a  large  scale 
for  the  improvement  of  polluted  waters  have  recently  been  devised  by  that 
city,  and  these  works  are  carefully  operated  to  reduce  the  noxious  properties 
of  the  Elbe  water  before  it  is  distributed  to  the  citizens.  This  work  of  purifi- 
cation is  not  intended  to  make  the  water  better  for  the  great  majority  of  the 
uses  to  which  it  is  applied,  but  to  make  it  a  water  which  the  inhabitants  can 
drink  with  the  least  risk  of  infection  from  typhoid  fever  and  other  water-carried 
diseases.  If  it  were  a  fact,  as  some  are  disposed  to  think,  that  the  people  of 
Hamburg  do  not  drink  water,  why  should  that  city  be  at  such  great  effort  and 
expense  to  render  the  water  of  the  Elbe  fit  to  drink  before  it  is  permitted  to 
go  to  the  consumers  ? 

"  But  the  most  pronounced  efforts  to  procure  a  supply  of  public  water  which 
certainly  shall  not  be  the  cause  of  infection  is  found  at  The  Hague,  where  the 
water  is  first  obtained  from  wells  driven  in  the  sand  dunes  and  afterwards 
passed  through  filters  of  sand,  the  grade  of  which  is  finer  than  that  of  nearly 
every  other  city  which  has  adopted  sand  filtration.  The  water  of  The  Hague 
as  it  comes  from  the  driven  wells  in  the  dunes  very  likely  is  equal  to  that  of 
any  of  the  driven  well  waters  which  we  are  accustomed  to  drink  with  a  feeling 
of  perfect  security.  But  the  officials  of  that  city,  not  content  with  a  water 
which  at  its  source  is  far  superior  to  nearly  all  of  our  public  waters,  set  about 
to  improve  its  hygienic  quality  by  slow  filtration  through  beds  of  fine  sand,  with 
the  result  that  their  city  has  had  for  many  years  nearly  the  lowest  recorded 
typhoid  fever  death  rate  of  any  of  the  large  cities  of  the  world.  Are  we  to 
ascribe  this  low  typhoid  rate  to  the  drinking  of  beer,  gin,  or  Schiedam  schnapps 
by  the  people  of  The  Hague,  or  shall  we  credit  it  to  the  drinking  of  this  excep- 
tionally pure  water  from  the  public  mains  ? 

"  From  such  information  as  the  author  has  been  able  to  obtain,  it  is  alto- 
gether probable  that  in  the  consumption  of  beverages  other  than  water  we  are 
quite  abreast  of  the  people  of  this  old  Dutch  city,  and  the  only  certain  differ- 
ence in  the  conditions  surrounding  the  two  cities  which  would  affect  the  typhoid 
rates  is  found  in  the  quality  of  their  respective  public  water  supplies. 

"  It  is  not  difficult  to  answer  the  second  question.  Nearly  all  the  water 
supplies  of  the  large  cities  of  this  country  are  polluted  with  household  sewage, 
and  are  the  carriers  of  the  typhoid  bacillus  from  the  sick  to  the  well.  Having 
knowledge  of  the  fact  that  many  of  our  large  cities  are  daily  drawing  water  for 
drinking  and  other  purposes  from  sources  of  known  sewage  pollution,  it  is 
proper  to  look  upon  the  typhoid  rates  of  such  cities  as  the  natural  result  of  this 
indifference  to  one  of  the  first  laws  of  health,  viz.,  a  pure  drinking-water. 

"  In  regard  to  the  third  line  of  inquiry  the  author  is  not  able  to  state  the 


80  THE   PURIFICATION  OF   WATER, 

per  capita  per  annum  consumption  of  beer  by  many  of  the  larger  cities  of 
Europe;  but  the  greatest  consumption  is  accredited  to  Munich,  which  for  one 
year  used  125  gallons  per  capita.*  An  investigation  of  the  probable  consump- 
tion of  beer  by  the  larger  cities  of  this  country  reveals  the  startling  fact  that 
even  the  city  of  Boston  consumed  65  gallons  of  beer  per  capita  during  the  year 
1894,  while  Cincinnati  indulged  itself  to  the  extent  of  80  gallons  per  capita,  and 
Milwaukee,  for  the  same  year,  reached  the  respectable  figure  of  105  gallons 
per  capita.  Of  the  list  of  ten  of  the  larger  cities  of  the  United  States,  the  low- 
est per  capita  per  annum  consumption  for  the  year  1894  was  46  gallons,  and  the 
highest  105  gallons.  The  amount  of  beer  made  and  drunk  in  the  United  States 
for  1894  allows  nearly  16  gallons  for  every  man,  woman,  and  child  of  the  whole 
population.  We  all  know  that  large  quantities  of  beer  (and  other  artificial 
beverages)  are  made  and  sold  in  this  country,  and  we  know  that  these  are  not 
substituted  for  the  industrial  and  sanitary  uses  of  water.  From  the  limited 
information  at  command,  I  am  sure  it  would  be  a  mistake  to  assume  that  the 
people  of  Europe  drink  nothing  but  beer,f  or  that  the  people  of  this  country 
drink  nothing  but  water." 

*  Encyclop&dia  Britannica,  ninth  edition,  vol.  xvii.,  p.  32. 

f  The  average  daily  consumption  of  water  by  Munich,  1895-1896,  was  12,947,683  U.  S. 
gallons,  corresponding  to  a  daily  per  capita  consumption  of  32.38  gallons. 


PURE  AND  PURIFIED    WATERS.  81 

f  ' 


CHAPTER   VI. 

PURE   AND    PURIFIED    WATERS. 

WATER  supplies  from  sources  of  known  purity  undoubtedly  are 
superior  to  purified  water  from  polluted  sources  ;  but  these  are  very 
rare,  and  only  a*  few  cities  peculiarly  favored,  like  Vienna,  Munich, 
and  Dresden  abroad,  and  some  of  the  smaller  cities  and  villages 
in  this  country,  can  make  them  available.  The  water  from  certain 
mountain  springs  and  streams,  and  from  some  deep  wells,  from 
the  standpoint  of  hygiene,  may  be  considered  "  pure ; "  while  that 
supplied  to  cities  where  filtration  or  sedimentation  in  large  reser- 
voirs is  practiced,  may  be  regarded  as  "  purified  "  water. 

Viewed  from  a  chemical  and  bacterial  standpoint,  there  is  no 
degree  to  pure  water  ;  but  from  the  hygienic  point  of  view  there 
may  be,  and  apparently  are,  degrees  of  purity.  The  water  of 
Vienna  is  said  to  be  naturally  pure,  so  is  the  water  of  Manchester 
(England)  and  New  York ;  but  accepting  the  typhoid  fever  rates 
as  an  index  of  water  quality,  the  water  of  Vienna  is  by  far  superior 
to  that  of  either  of  the  other  two  cities.  Manchester  and  New 
York  attempt  to  protect  the  drainage  grounds  of  their  sources, 
and  preserve  the  water  from  direct  sewage  pollution,  which  efforts 
are  only  partially  successful.  Vienna,  Munich,  and  a  few  other 
cities  seek  their  water  supplies  in  sources  which  apparently  are 
beyond  the  reach  of  pollution. 

Liverpool,  like  New  York  and  Boston  (new  works),  has  sought 
its  water  supply  in  a  district  which  is  sparsely  inhabited,  and  not 
exposed  to  the  sewage  from  large  organized  communities  ;  and  as 
an  additional  precaution  in  behalf  of  the  public  health,  provision 
is  made  for  filtration  of  this  water  before  it  reaches  the  city. 

In  considering  sources  of  water  supply  in  mountain  springs  at 
moderate  distance  from  cities  to  be  supplied,  and  sources  in  deep 
wells,  it  should  not  be  overlooked  that  similar  sources  cannot  be 


82  THE   PURIFICATION  OF    WATER. 

made  available  for  all  or  even  many  cities.  Nor  should  the  fact 
be  ignored,  that  the  enormous  per  capita  consumption  in  nearly 
every  American  city  renders  the  problem  of  a  "  pure  "  or  "puri- 
fied" water  supply  for  our  cities  much  more  difficult  of  solution 
than  in  the  cities  of  Europe.  Berlin,  with  about  the  same  popula- 
tion as  Chicago,  uses  less- than  one-fourth  of  the  quantity  of  water 
per  diem  ;  London,  with  a  population  of  over  5,000,000,  probably 
uses  no  more  water  than  Philadelphia ;  while  Hamburg,  with  nearly 
twice  the  population  of  Cincinnati,  uses  less  than  three-fourths  as 
much  water.  The  consumption  or  rather  the  waste  of  water  in 
many  cities,  is  a  serious  impediment  to  improvement  in  works  of 
public  water  supply ;  and  the  abuse  of  water  privileges  must  be 
curbed,  if  we  are  to  have  water  of  the  same  quality  as  that  of  many 
of  the  cities  of  Europe. 

Of  the  larger  cities  of  the  United  States  which  derive  their 
water  supplies  from  driven  wells,  Brooklyn  thus  obtains  from 
many  sources,  covering  a  large  territory,  about  32,000,000  gallons 
per  day,*  or  over  four-tenths  of  the  daily  supply.  The  maximum 
yield  of  the  system  of  artesian  wells  at  Memphis,  Tenn.,  has  been 
stated  at  16,000,000  gallons  per  day.f  The  maximum  capacity  of 
the  system  of  driven  wells  at  Dayton,  Ohio,  is  given  as  6,750,000 
gallons,  and  at  Lowell,  Mass.,  as  12,000,000  gallons  per  day.J 
Upon  the  same  authority  the  average  daily  consumption  of  water 
from  the  system  of  driven  wells  at  South  Bend,  Ind.,  is  1,900,000 
gallons  ;  and  the  maximum  daily  consumption  from  the  artesian 
wells  at  Jacksonville,  Fla.,  is  given  as  1,557,557  gallons.  Many 
smaller  cities  have  systems  of  artesian  or  non-flowing  wells  which 
yield  from  a  few  hundred  thousand  to  one  or  two  million  gallons 
per  day,  and  all  such  may  be  regarded  as  highly  favored  by  nature 
in  the  matter  of  their  public  water  supplies. 

In  Europe,  especially  in  Germany,  it  is  the  policy  to  seek 
public  water  supplies  in  sources  of  natural  purity,  such  as  moun- 
tain springs  and  deep  wells,  where  these  are  available,  and  to 


*  Mr.  I.   M.  DeVarona,  in  Report  on  the  Future  Extension  of  the  Water  Supply  of  the 
City  of  Brooklyn,  189(5,  p.  26. 

f  Report  on  Extension  and  Betterment  of  Cincinnati  Water-Works,  1896,  p.  27. 
J  Manual  of  American  Water-Works,  1897. 


PURE   AND  PURIFIED    WATERS.  83 

limit  the  consumption  of  water  to  the  yield  'of  such  sources. 
When  the  yield,  as  at  Dortmund  for  instance  is  relatively  large, 
the  allowance  per  capita  per  diem  is  correspondingly  liberal ;  while 
at  Leipsic,  where  the  yield  of  ground  water  is  relatively  small, 
the  per  capita  consumption  also  is  small. 

In  order  to  utilize  to  the  fullest  extent  the  natural  sources  of 
pure  water  for  public  supply,  the  people  of  Germany  are  willing 
to  limit  the  use  and  waste  of  such  water  sometimes  to  very  small 
•per  capita  daily  allowances,  reasoning,  doubtless,  that  the  require- 
ments of  hygiene  are  better  satisfied  with  small  amounts  of  pure 
water  than  large  volumes  of  polluted  water. 

Among  the  larger  cities  of  Europe  which  depend  partly  or 
wholly  upon  ground  waters  may  be  mentioned  London,  the  Kent 
Works  of  which  during  July,  1896,  supplied  from  deep  wells  a 
daily  average  of  23,270,000  U.  S.  gallons  to  an  estimated  popula- 
tion of  583,436,  allowing  thus  nearly  40  gallons  per  capita. 

In  the  table  on  the  following  page  are  given  the  principal 
cities  of  Germany,  etc.,  which  depend  in  whole  or  part  on  ground 
water  supplies.* 

If  the  double  system  of  water  supply  which  prevails  in  parts  of 
Paris  (where  the  very  excellent  water  of  the  Vanne  is  used  for 
dietetic  purposes)  should  be  adopted  by  cities  in  this  country, 
then  it  will  in  most  instances  become  a  comparatively  easy  task  to 
secure  the  limited  quantity  of  water  required  for  drinking  and  culi- 
nary uses,  either  from  sources  of  known  purity  or  by  very  careful 
filtration. 

The  great  advantage  of  water  from  a  source  not  open  to  sew- 
age or  semi-sewage  pollution,  as,  for  instance,  deep  wells  intercept- 
ing water  which  has  been  thoroughly  purified  in  passing  through 
the  drift,  over  water  purified  by  any  process  of  filtration,  is  found 
in  the  fact  that  such  water  is  at  all  times  safe ;  whilesafety  to  the 
public  of  purified  water  depends  altogether  upon  the  skill  and  care 
of  the  officials  in  charge  of  the  filters.  A  lack  of  technical  knowl- 
edge or  vigilance  upon  their  part  may  result  in  great  damage  to 
the  health  of  the  people  supplied. 

Naturally  "pure"  water  is  not  available  by  the  great  majority 

*  Statistische  Zusammenstellung  der  Betriebs  Ergebnisse  von  Wasser-werken,  Munich,  1895. 


84 


THE   PURIFICATION  OF   WATER. 


of  cities.  To  supply  a  so-called  pure  water  to  London  from 
sources  in  Wales,  nearly  $200,000,000  will  be  required  ;  and  even 
in  that  instance  it  is  proposed  by  the  County  Council  to  filter  the 

GERMAN    CITIES   SUPPLIED   WITH   GROUND   WATER. 


CITIES. 

DATE 

OF 

REPORT. 

POPULATION. 

DAILY  YIELD 
OF  WELLS. 
U.  S.  GALS. 

PER  CAPITA 
DAILY 
ALLOWANCE. 
U.  S.  GALS. 

PROPORTION 
OF  WATER 
FROM  WELLS. 

Schalke, 

1893 

280,000 

11,429,790 

40.8 

All. 

Dortmund, 

1893-4 

170,000 

9,617,260 

56.6 

" 

Cologne, 

1893-4 

286,000 

8,425,535 

29.5 

" 

Dresden, 

1893 

309,000 

6,912,000 

22.4 

» 

Bochum, 

1893-4 

148,500 

6,764,100 

45.5 

it 

Leipsic, 

1893 

391,000 

6,131,170 

15.7 

u 

Stockholm, 

1893 

251,000 

6,045,850 

24. 

U 

Copenhagen, 

1893 

337,500 

5,990,789 

17.8* 

Essen, 

1893-4 

135,000 

4,869,495 

•     36. 

All. 

Barmen, 

1893-4 

125,000 

4,380,533 

35. 

U 

Augsburg, 

1893 

80,000 

4,253,900 

53.2 

" 

Dusseldorf, 

1893-4 

157,000 

4,204,468 

27. 

U 

Charlottenburg, 

1892-3 

255,000 

4,204,987 

15.8 

U 

Elberfeld, 

1893-4 

144,000, 

3,906,663 

27.1 

U 

Miilheim,  Ruhr, 

1893-4 

67,000 

3,729,280 

55.7 

it 

Hannover, 

1893-4 

221,000 

3,477,132 

15.7 

II 

Freiberg, 

1893 

51,000 

3,157,980 

62. 

" 

Frankfort, 

1893 

198,800 

3,057,138 

.  .  . 

40$ 

Duisburg, 

1893-4 

73,875 

2,793,280 

37.8 

All. 

Carlsruhe, 

1893 

80,000 

2,7.63,514 

34.5 

ii 

Halle, 

1893-4 

123,000 

2,605,294 

21.1 

a 

Crefeld, 

1893-4 

106,000 

2,301,588 

22.0 

II 

Witten, 

1893-4 

45,000 

2,195,849 

48.8 

II 

Strasburg, 

1893-4 

95,000 

1,964,511 

20.6 

ti 

Vienna, 

1893 

998,000 

1,877,795 

10# 

Upon  this  aspect 


water  before  it  is  delivered  to  the  consumers, 
of  the  water  question  Dr.  Leff man  f  says  :  — 

"  When  propositions  for  nitration  are  made,  it  is  usual  for  some  persons 
to  suggest  that  a  pure  water  supply  should  be  selected.  .  .  .  Surface  water 
is  so  liable  to  pollution  that  the  word  « pure '  has,  in  regard  to  it,  only  a  com- 
parative sense ;  and  in  establishing  an  elaborate  water  supply,  we  should  estab- 
lish systems  of  storage  and  nitration,  no  matter  how  excellent  may  be  the 
district  in  which  the  water  is  collected  and  through  which  it  flows." 

*  Springs  and  wells,  proportion  not  given.  f  Public  Health,  1897,  p.  118. 


PURE   AND   PURIFIED    WATERS.  85 

Changes  may  occur  in  the  quality  of  water  from  natural  sources 
by  subsequent  pollution  of  the  tributary  watersheds.  Large  water- 
sheds constituting  the  sources  of  supply  for  cities  are  more  exposed 
than  small  watersheds  used  by  villages,  and  absolute  security  in 
either  case  is  to  be  had  only  by  complete  control  of  the  effective 
drainage  grounds. 

The  water  of  deep  wells  may  become  polluted  by  sewage  from 
improvements  which  encroach  on  their  drainage  area  ;  and  the  area 
drained  by  such  wells  should  be  free  from  habitation,  and  such 
commercial  operations  as  are  calculated  to  contaminate  the  soil  and 
pollute  the  rainfall  which  percolates  through  the  soil  to  the  wells. 

A  proposition  by  the  author  (1894)  to  sterilize  by  distillation, 
and  distribute  through  a  separate  system  of  mains,  that  portion  of 
a  city  water  supply  which  was  used  for  drinking  and  dietetic  pur- 
poses, developed  much  adverse  criticism.  Partly,  as  alleged,  be- 
cause such  water,  when  deprived  of  the  minerals  in  solution,  would 
not  be  so  favorable  to  the  animal  system  as  are  natural  waters  ; 
partly  because  of  the  difficulty  of  educating  people  to  the  use  of 
sterilized  water  when  other  water  was  less  expensive  and  more 
convenient  to  obtain;  and  partly  because  of  the  expense  of  a  dupli- 
cate system  of  mains  to  distribute  such  water  to  the  consumers. 

The  first  objection  is  the  only  one  worthy  of  serious  considera- 
tion. If  it  is  true  that  sterilized  water  exerts  a  prejudicial  influence 
on  digestion  or  any  of  the  animal  functions,  then  it  should  not  be 
recommended  ;  but  observation  among  people  who  are  regularly 
using  distilled  water  does  not  bear  out  the  assertion  sometimes  made, 
that  such  water  is  less  beneficial  for  dietetic  uses  than  clean  cistern 
or  pure  well  water.  Neither  is  the  author  aware  that  systematic 
experiments  have  ever  been  conducted  to  ascertain  the  real  influence 
of  sterilized  water  on  the  human  system,  unless  it  may  be  held 
that  the  favorable  results  of  the  use  of  distilled  water  in  the  United 
States  navy  and  on  ocean  steamships  furnishes  the  desired  data. 
If  the  salts  and  minerals  lost  by  distillation  are  really  essential  to 
a  perfect  drinking-water,  it  would  seem  to  be  much  safer  to  add 
these  in  proper  proportions  to  distilled  water,  than  to  assume  the 
risk  to  health  which  accompanies  the  indiscriminate  use  of  natural 
waters  for  drinking. 


86  THE   PURIFICATION  OF   WATER. 

If  it  were  true  that  a  distilled  water,  lacking  in  lime,  soda, 
potash,  etc.,  was  unfitted  for  the  manufacture  of  teeth  and  bone  in 
young  children,  this  fact  should  be  manifest  in  the  children  of 
suburban  and  other  villages,  which  depend  almost  entirely  for 
drinking  upon  cistern  water.  The  author's  observation  for  many 
years  along  this  line  furnishes  no  proof  that  cistern  water,  if  clean 
and  free  from  objectionable  organic  matter  and  bacteria,  is  not  a 
perfectly  safe  and  satisfactory  drinking-water.  In  fact,  rain-water 
falling  in  suburban  districts,  caught  on  clean  slate  roofs,  and  col- 
lected in  clean  cisterns,  should  furnish  the  purest  and  best  of 
natural  waters.  Underground  cisterns  intended  for  the  collection 
and  storage  of  drinking-waters  should  be  tight,  and  not  subject  to 
contamination  through  the  soil  from  neighboring  cesspools  and 
vaults ;  otherwise,  pollution  may  occur,  and  such  cistern  water 
would  be  quite  as  objectionable  in  a  hygienic  view  as  any  other 
sewage-polluted  water. 

Certain  spring  and  well  waters  may  be  quite  free  from  organic 
matter  and  bacteria,  and  still  be  dangerous  to  health  by  reason  of 
minerals  in  solution.  Lead,  arsenic,  copper,  etc.,  and  iron  in  excess, 
are  objectionable  ingredients  of  drinking-waters  ;  and  petroleum 
above  one  part  in  two  millions,  it  has  been  stated,  unfits  water  for 
drinking.*  Some  of  these  substances  may  be  in  waters  which,  when 
tested  by  bacteriological  methods  and  the  microscope,  would  be 
found  very  pure.  Chemistry,  however,  can  reveal  and  measure  them. 

While  certain  surface  waters  can  be  carried  in  large,  deep  res- 
ervoirs with  an  improvement  in  quality,  water  from  ground  sources 
cannot  be  stored  in  open  shallow  reservoirs  without  developing  a 
growth  of  vegetable  and  animal  matter,  the  luxuriance  of  which 
depends  upon  the  climate  and  sunlight,  and  to  some  extent  upon 
the  mineral  constituents  of  the  water.  Tall  tanks  and  stand-pipes, 
the  depth  of  which  is  usually  greater  than  that  of  earthen  reser- 
voirs, and  the  water  area  small  in  relation  to  capacity,  may  be 
used  to  store  ground  waters  without  apparent  change  in  quality ; 
but  in  these  the  quantity  of  water  stored  is  always  small  when 
compared  with  the  daily  consumption. 

*   Water  Supply,  Chemical  and  Sanitary,  Wm.  Ripley  Nichols,  New  York,  1883,  p.  75. 


PURE   AND   PURIFIED    WATERS.  87 

The  investigations  of  Mr.  G.  C.  Whipple,  of*the  Massachusetts 
State  Board  of  Health,*  show  very  conclusively  that  sunlight  is 
the  controlling  factor  in  the  development  of  algous  growths  in 
stored  waters,  which  suggests  that  the  light  should  always  be 
rigorously  excluded  from  reservoirs  and  large  tanks  intended  for 
the  reception  of  ground  waters.  It  has  been  the  author's  usual 
practice  to  cover  steel  tanks  and  towers  for  the  storage  of  ground 
waters,  but  he  is  not  aware  of  any  trouble  or  complaint  arising 
from  the  storage  of  ground  waters  in  the  few  open  tanks  of  works 
with  which  he  has  been  associated. 

According  to  Professor  Mason, f  "  to  keep  a  ground  water  in 
good  condition  it  is  necessary  to  cover  the  reservoir.  Such  waters 
are  usually  charged  with  mineral  matter  suitable  for  plant  food, 
and  the  higher  organisms  will  be  likely  to  grow  therein  unless 
light  be  excluded." 

The  rapid  development,  during  the  summer,  of  vegetable 
growths  in  shallow  open  reservoirs  carrying  ground  waters,  is  well 
known  ;  and  the  growth  and  (or)  decay  of  some  of  these  organisms 
have  produced  unpleasant  tastes  and  odors  in  stored  waters,  but  no 
proof  is  at  hand  that  they  have  been  the  specific  cause  of  disease. 
Numerous  investigations  have  shown  that  asterionella,  nostoc,  oscil- 
laria,  and  other  of  the  green  algce,  crenotJirix  (fungi)  and  uroglena 
(infusoria),  have  each  at  times  imparted  peculiar  tastes  or  odors  to 
stored  waters  ;  and  it  is  altogether  likely  that  other  of  the  micro- 
scopic organisms  in  water  may  be  concerned  in  producing  effects 
which  justify  objections  to  the  use  of  such  waters  from  an  aesthetic 
standpoint,  even  if  not  positively  injurious  to  health. 

Assuming  that  the  development  of  vegetable  organisms  in 
stored  waters  depends  principally  upon  the  penetration  of  light, 
it  is  obvious  why  turbid  river  and  surface  waters  can  be  stored  in 
large,  deep  reservoirs  for  great  lengths  of  time  without  injury,  and, 
as  a  rule,  with  positive  improvement  in  their  quality.  During  the 
early  days  of  storage  the  color  is  so  strong,  and  the  water  so  nearly 
opaque,  that  there  is  no  penetration  of  light ;  and  upon  subsidence 
of  the  heavier  matters  in  suspension  many  of  the  vegetable  organ- 

*  Journal  of  New  England  Water  Works  Association,  September,  1896. 
t    Water  Supply,  by  William  P.  Mason,  New  York,  1896,  p.  261.  m 


88  THE  PURIFICATION  OF   WATER. 

isms,  including  the  bacteria,  are  carried  down,  and  deposited  on  the 
bottom  and  slopes  of  the  reservoirs.  Upon  the  other  hand,  the 
usual  properties  of  ground  water,  viz.,  — 

(1)  Limpidity  and  lack  of  color, 

(2)  Small  or  no  organic  matters  in  suspension, 

(3)  Large  amounts  of   dissolved    salts  readily  assimilable  by 
plant  life,  —  are  favorable  to  the  growth  of  cryptogams. 

Add  to  these  light  and  heat  by  exposure  in  open  reservoirs, 
and  all  the  conditions  are  present  essential  to  the  rapid  growth  of 
algae.  The  Vanne  water,  which  is  used  for  dietetic  purposes  in 
portions  of  Paris,  is  obtained  from  springs ;  and  to  preserve  it 
without  change  of  quality  it  is  conducted  to  the  city  in  a  closed 
conduit,  received  in  distributing  reservoirs  from  which  the  light 
is  carefully  excluded,  and  reaches  the  consumer  quite  as  pure  as 
it  was  upon  issuing  from  its  mountain  source. 

The  smaller  cities  and  villages  often  are  peculiarly  favored  in 
sources  of  satisfactory  public  water  supply ;  while  larger  cities, 
where  the  consumption  of  water  per  capita  and  in  the  aggregate 
is  greatly  in  excess  of  that  of  the  smaller  communities,  are 
compelled  to  procure  the  required  daily  volumes  of  water,  in 
many  instances,  from  sources  utterly  unfit  for  domestic  uses.  A 
mountain  spring  or  system  of  driven  wells,  which  will  furnish  an 
abundance  of  pure  water  to  some  small  municipality,  would  be 
too  insignificant  for  consideration  as  a  source  of  water  supply 
to  a  city  ;  and  intelligent  people  are  prone  to  neglect  the  fact  that 
a  water  source  which  may  meet  the  requirements  of  a  village  of 
a  few  thousand  population  would  be  inadequate  to  supply  even 
the  drinking  and  culinary  water  of  a  large  city. 

Referring  to  present  sources  of  city  water  supply,  it  can  be 
said  that  Vienna,  Munich,  Dresden,  Stockholm,  Copenhagen,  a 
portion  of  Paris  and  other  cities  abroad,  together  with  several  of  the 
smaller  cities  and  many  villages  in  this  country,  have  water  sup- 
plies which  are  naturally  pure  ;  while  London  (omitting  the  Kent 
Works),  Berlin,  Hamburg,  Liverpool,  and  many  smaller  cities  in 
Europe,  Lawrence,  Mass.,  and  several  other  cities  in  this  country, 
have  purified  water  supplies. 


PUKE   AND   PURIFIED    WATERS.  89 

• 

In  this  connection  it  is  difficult  to  discuss  the  water  supplies  of 
cities  in  America  using  mechanical  filters.  The  typhoid  fever  rates 
of  these  cities  are  considerably  higher  than  the  rates  of  cities  in 
Europe  which  use  plain  sand  filtration  for  the  purification  of 
polluted  waters  ;  and  inquiry  among  the  manufacturers  of  the 
filters,  and  the  officials  of  the  water-works  using  them,  reveals  the 
startling  information  that  (in  instances  at  least)  the  filtered  water 
is  not  generally  used  by  the  people  of  such  cities.  This  is  also 
true  of  certain  cities  and  villages  which  have  very  excellent  water 
supplies  from  natural  sources. 

In  a  certain  city  of  Ohio,  where  the  public  water  supply  is  from 
a  system  of  driven  wells  and  of  very  excellent  quality,  it  is  said 
that  less  than  one-fourth  of  the  population  draw  their  water  supply 
from  the  city  mains.  The  remainder,  after  nearly  thirty  years' 
experience  with  a  public  system  of  water- works,  still  depend  for 
domestic  purposes  upon  the  water  from  wells  and  cisterns.  In  the 
interest  of  the  public  health,  and  where  the  public  water  supply  is 
unexceptional,  the  use  of  wells  and  cisterns  for  drinking-water 
should  be  prohibited  (as  they  are  in  Vienna),  and  the  use  of  the 
public  water  be  made  compulsory.  Of  what  avail  is  it  to  secure 
water  of  high  quality  if  the  people  are  permitted  afterwards  to 
take  their  drinking  and  dietetic  water  from  sources  of  doubtful 
value,  and,  as  is  well  known  to  many  sanitary  officers,  from  sources 
exposed  to  sewage  pollution  ? 

It  is  a  strange  anomaly  that  in  the  larger  cities  (many  of  which 
are  supplied  with  sewage-polluted  waters)  all  the  people  are  by 
the  force  of  circumstances  compelled  to  take  their  water  from  the 
public  mains,  while  in  the  small  cities  and  villages,  in  which  the 
public  water  is  often  of  most  excellent  quality,  the  use  of  the  better 
water  is  altogether  optional  with  the  people. 

It  is  impossible  to  tell  how  much  physical  suffering  might  be 
traced  to  water  supplies,  which  are  regarded  by  municipal  corpora- 
tions and  water  companies  as  fit  for  domestic  uses,  and  to  the 
continuous  use  by  cities  of  waters  of  known  sewage  pollution. 
Certain  it  is  that  typhoid  fever,  cholera  (in  the  Orient),  and  other 
intestinal  disorders,  annually  claim  thousands  of  victims,  which 
would  be  saved  if  all  people  were  equally  and  sincerely  interested 


90  THE  PURIFICATION  OF   WATER, 

in  having  drinking  and  dietetic  waters  of  the  highest  attainable 
purity. 

In  the  mountains,  where  the  population  is  sparse,  water  of  sat- 
isfactory quality  and  in  abundance  is  often  found.  But  at  lower 
elevations,  along  the  rivers  and  lakes,  and  at  tide  water,  where  the 
people  are  collected  in  large  numbers,  mountain  sources  of  water 
supply  are  rarely  available.  Doubtless  "  there  is  enough  whole- 
some water  on  the  face  of  the  earth  to  supply  all  the  inhabitants 
thereof,"  but  the  conditions  clearly  demonstrate  that  this  is  not 
well  distributed. 

Cities  have  been  located,  not  according  to  the  rules  of  hygiene, 
but  according  to  the  requirements  of  commerce.  Revenue  has 
been  the  dominating  factor ;  and  upon  the  sanitarian  has  fallen 
the  burden  of  rectifying  evils  which  have  followed  the  total  disre- 
gard in  so  many  cases  of  the  fundamental  laws  of  health. 

In  the  introduction  to  this  work  a  statement  is  made  that 
"water  is  an  essential  of  human  existence;"  and  this  is  true,  not 
only  as  it  is  used  in  connection  with  the  body  needs,  but  in  con- 
nection with  the  fruits  of  the  soil,  in  tempering  the  atmosphere 
and  heat  of  the  earth's  crust,  and  in  many  other  ways.  Restricted 
to  our  animal  requirements,  it  may  be  said  that  "  pure  water  "  is 
"an  essential  of  health,"  while  "impure  water"  involves  hazards 
to  life  and  health  which  we  have  no  right  to  incur. 

It  is  feasible  for  a  small  percentage  of  the  world's  population 
to  procure  water  supplies  from  natural  sources  which  will  satisfy 
the  most  advanced  requirements  of  hygiene,  but  for  the  great 
majority  of  the  people  satisfactory  water  supplies  are  obtainable 
only  by  works  of  artificial  purification. 


CITATIONS  ON  TYPHOID  FEVER  EPIDEMICS.  91 


CHAPTER    VII. 

CITATIONS    ON   TYPHOID    FEVER   EPIDEMICS. 

PRACTICAL  illustrations,  so  far  as  they  are  available,  concerning 
the  causes  of  typhoid  fever  epidemics,  are  especially  valuable  in 
supporting  the  theory  that  a  sewage-polluted  water,  or  a  water 
carrying  the  germs  of  typhoid  fever,  will  produce  infection  of  the 
same  disease  in  persons  who  may  drink  such  water,  or  who  in 
some  way  may  have  ingested  food  which  has  been  in  contact  with 
such  water.  In  this  connection  it  is  not  necessary  that  a  line 
should  be  drawn  between  the  colon  bacillus  and  the  typhoid  bacil- 
lus as  found  in  the  human  spleen  ;  either  or  both  may  be  going 
into  the  sewers  of  cities,  and  from  the  sewers  into  rivers,  lakes, 
and  other  sources  of  public  water  supply.  It  is  sufficient  and 
prudent  to  assume  that  the  dejections  of  a  typhoid  patient  may 
contain  the  specific  organism  which  is  the  cause  of  this  disease, 
and  in  the  instances  noted  in  this  chapter  the  evidence  is  at  times 
overwhelmingly  in  support  of  this  view. 

LAUSEN,  SWITZERLAND. 

The  typhoid  epidemic  which  occurred  in  this  village  during  the 
latter  part  of  1872  has  been  mentioned  so  frequently  and  with  so 
much  respect  as  to  make  it  a  classic  in  the  epidemiology  of  this 
disease.  The  circumstances  were  briefly  as  follows  :  A  few  cases 
of  typhoid  fever,  occurring  at  a  distance  of  one  or  two  miles 
from  the  village,  were  supposed  to  have  caused  a  contamination  of 
the  water  of  the  village  well,  from  which  an  infection  of  130  per- 
sons, with  8  fatalities,  in  due  time  followed.  From  the  official 
report  of  the  epidemic  by  the  health  officer  of  Basle,  it  appears 
that  a  brook,  passing  near  the  premises  where  the  original  cases 
of  typhoid  occurred,  was  used  for  the  washing  of  the  linen  of  the 
patients,  and  at  the  same  time  as  a  channel  for  the  disposal  of 


92  THE  PURIFICATION  OF   WATER. 

the  typhoid  dejections.  The  course  of  this  brook  caused  it  to 
join  another  stream  which  passed  through  Lausen  at  a  considera- 
ble distance  below  the  village ;  but  for  some  time  it  had  been  sus- 
pected that  an  underground  connection  existed  between  the  brook 
at  a  place  below  the  original  location  of  the  fever  and  the  village 
well,  although  from  surface  indications,  any  sewage  discharged 
into  the  brook  would  pass  into  the  larger  stream  below  the  village, 
and  not  be  the  cause  of  pollution  to  the  village  water  or  create  an 
offense  to  its  population. 

After  the  epidemic,  an  investigation  showed  that  the  brook 
did  have  an  underground  connection  with  the  village  well ;  and 
notwithstanding  the  percolation  of  the  water  through  a  mile  or 
more  of  pervious  material,  typhoid  germs,  which  came  into  the 
brook  from  the  source  of  the  original  infection,  were  carried  into 
the  public  well,  and  spread  the  disease  in  the  village  at  such  an 
alarming  rate  that  one  in  every  six  of  the  whole  population  was 
attacked.  The  original  case  of  typhoid  fever  was  held  to  have 
been  imported  into  the  neighborhood  of  Lausen. 

A  resumJ  of  the  simple  facts  in  this  instance  shows  :  — 

1.  No  typhoid  fever  had  been  known  of  in  Lausen  for  sixty 

years,  and  the  general  health  of  the  people  was  excep- 
tionally good. 

2.  During  the  summer  of  1872,  several  cases  of  typhoid  had 

occurred  outside  of  the  village,  at  a  distance  of  a  mile 
or  more. 

3.  The  Furlen  Brook  was  used  as  a  channel  of  discharge  for 

the   dejections   of   the    original    patients,   and   for    the 
washing  of  their  linen. 

4.  Salt,  thrown  into  the  brook  below  the  original  location  of 

the  disease,  in  due  time  appeared  in  the  water  of  the 
Lausen  public  well. 

5.  The  infection  was  limited  to  those  who  drank  of  the  water 

of  the  public  well,  while  families  which  abstained  from 
the  use  of  the  water  of  this  well  were  not  affected. 

The  Lausen  circumstance  has  been  so  well  described  in  certain 
books  and  reports  upon  the  subject,  that  it  is  here  introduced 


CITATIONS   ON   TYPHOID   FEVER  EPIDEMICS,  93 

t 

principally  to  show  that  natural  filtration  so-called,  through  the 
pervious  materials  of  the  drift,  while  it  may  render  water  very  fair 
to  look  upon,  cannot  be  accepted  as  a  safeguard  against  typhoid 
infection,  if  the  cause  of  infection  should  exist  in  the  locality  of  a 
source  of  ground  water  supply  such  as  was  had  in  Lausen. 

CATERHAM,  ENGLAND. 

The  outbreak  of  typhoid  fever  at  Caterham  occurred  in  the 
early  part  of  1879,  and  was  reported  on  early  in  April  of  that  year. 
In  this  instance  there  were  upward  of  100  attacks  of  the  disease, 
of  which  19  were  fatal.  It  was  proved  beyond  doubt  (according 
to  Mr.  Edward  Easton,  Chairman  of  the  Caterham  Water  Com- 
pany), that  the  origin  of  the  epidemic  was  due  to  the  evacuations 
of  one  workman  accidentally  contaminating  the  water  of  the  well. 
This  workman,  although  suffering  with  a  "  walking "  case  of  ty- 
phoid fever,  was  employed  in  the  tunnels  connecting  the  wells 
which  constituted  the  source  of  water  supply  for  Caterham  and 
Redhill.  While  so  employed,  his  frequent  dejections  were  col- 
lected in  a  bucket,  and  from  time  to  time  hoisted  out  of  the  well. 
During  one  trip  of  the  bucket  an  accident  occurred,  causing  a  por- 
tion of  its  contents  to  be  spilled  into  the  water  ;  and  from  this  in 
due  time  grew  an  epidemic  of  typhoid  fever,  alarming  in  propor- 
tion to  the  population  of  the  district  supplied  from  this  source. 

Of  this  unfortunate  occurrence,  Dr.  Thorne  Thorne,  who  con- 
ducted the  investigation,*  says  :  — 

"  The  water  supply  of  Redhill  and  Caterham  was  derived  from  deep  wells 
in  the  chalk  and  lower  greensand.  It  was  discovered  that  a  workman  em- 
ployed in  excavating  an  adit  between  two  of  the  wells  had  previously  con- 
tracted enteric  (typhoid)  fever  at  Croydon,  and  had  been  overtaken  by  diarrhoea 
on  several  occasions  while  working  in  the  well.  There  appeared  no  doubt 
that  the  poison  of  the  excreta  was  conveyed  to  the  drinkers  of  the  well  water, 
and  communicated  the  disease." 

The  circumstances  of  the  affair  are  revolting  in  the  extreme  ; 
and  how  a  person  suffering  with  the  early  symptoms  of  typhoid 
could  be  permitted  to  follow  his  occupation  immediately  in  the 

*  "  Report  Royal  Commission  on  Metropolitan  Water  Supply,"  Appendices  to  Minutes  of 
Evidence,  p.  533. 


94  THE  PURIFICATION  OF   WATER. 

presence  of  the  water  from  which  a  small  population  drew  its  daily 
supply,  is  beyond  comprehension. 

Aside  from  a  specific  cause  of  disease  which  may  be  traced  to 
this  lapse  of  moral  responsibility  upon  the  part  of  some  one,  it  is 
disgusting  to  know  that  a  man  would  be  so  far  lost  to  the  sense  of 
decency  as  to  continue  his  labors  under  conditions  like  these.  Here 
was  a 'system  of  wells  from  which  a  large  number  of  people  were 
daily  drawing  water  for  drinking  and  other  purposes,  in  which 
some  repairs  or  improvements  were  being  conducted  while  the 
water  was  being  pumped  out  of  them  for  domestic  consumption, 
and  a  workman  known  to  be  suffering  with  diarrhea,  if  nothing 
worse,  was  permitted  to  follow  his  labors  in  the  wells,  and  dispose 
of  his  dejections  in  a  manner  which  was  offensive  to  sentiment, 
even  if  proper  precautions  had  been  observed  to  prevent  contami- 
nation of  the  water.  But  such  precautions  were  not  observed  ;  and 
in  due  time  the  bucket  was  tipped,  some  of  its  contents  went  into 
the  water,  and  upwards  of  100  persons  were  made  to  suffer  as  a 
consequence  of  a  proceeding  which  was  little  short  of  a  crime. 

In  the  exhaustive  examination  conducted  by  the  Royal  Com- 
mission on  Water  Supply  for  London  (1893),  this  Caterham  oc- 
currence is  mentioned  several  times  by  the  witnesses  ;  and  the 
principal  deduction  drawn  from  it  by  the  Commission  was,  that  if 
the  dejections  of  this  workman  had  been  tipped  into  the  River 
Thames  instead  of  the  Caterham  wells,  it  would  have  been  so 
largely  diluted  as  to  have  had  no  effect  on  the  health  of  the  people 
who  take  their  water  from  the  Thames  companies. 

Stripping  the  matter  of  all  verbiage,  it  appears  that  100  cases 
of  typhoid  fever  with  19  deaths  were  traced  to  the  contamina- 
tion of  this  Caterham  water,  by  the  accidental  discharge  of  a  portion 
of  the  dejecta  from  a  mild  case  of  typhoid  fever. 

PLYMOUTH,  PA. 

The  town  of  Plymouth,  Pa.,  in  the  spring  of  1885  was  visited 
by  a  severe  epidemic  of  typhoid  fever,  which  had  its  origin  in  the 
pollution  of  the  public  water  supply  by  the  dejections  of  a  single 
isolated  patient. 

The  water  of  the  town  is  impounded  in  a  reservoir  at  an  eleva- 


CITATIONS   ON   TYPHOID   FEVER  EPIDEMICS.  95 

* 

tion  sufficient  to  maintain  a  supply  by  gravity ;  and  upon  the  drain- 
age ground  of  this  reservoir,  at  the  time  of  and  before  the  epi- 
demic, lived  a  family,  a  member  of  which  was  temporarily  located 
in  Philadelphia.  This  member  came  home  ill  with  typhoid  fever 
during  the  winter  of  1884-1885  ;  and  to  avoid  infection  of  the 
family  vault,  his  dejections  were  thrown  upon  the  snow  or  ice-cov- 
ered ground  some  distance  from  the  residence.  When  the  warm 
rains  of  late  winter  set  in,  the  snow  and  ice  about  the  premises 
melted,  and  ran  into  the  reservoir.  Within  two  or  three  weeks  an 
epidemic  of  typhoid  fever  occurred  in  Plymouth  ;  and  out  of  a  pop- 
ulation of  about  8,000,  over  1,100  were  stricken  with  the  disease, 
of  which  114  were  fatal  cases. 

In  the  Lausen  epidemic,  the  typhoid  germs  went  into  the 
water  of  the  Furlen  brook  ;  the  water  of  the  brook,  or  a  portion  of 
it,  went  into  the  village  well.  Result,  an  epidemic  of  typhoid 
fever  in  a  little  village  which  for  more  than  two  generations  had 
been  wholly  exempt  from  this  disease. 

In  the  Caterham  and  Redhill  epidemic  the  dejections  of  a 
typhoid  patient  were  mixed  with  the  water  of  a  well  which  con- 
stituted the  source  of  supply  for  a  small  population ;  this  water 
was  pumped  to  the  patrons  of  the  water  company,  and  an  epi- 
demic of  typhoid  fever  followed. 

In  the  Plymouth  epidemic,  the  typhoid  fever  dejections  were 
thrown  upon  the  frozen  soil ;  rains  followed,  and  the  runoff  of 
rainfall  and  melted  ice  carried  these  into  the  reservoir  which  con- 
stituted the  water  supply  for  the  city.  Result,  a  typhoid  epidemic 
which  at  the  time  attracted  the  attention  of  the  whole  country. 

In  connection  with  the  epidemic  at  Plymouth,  Pa.,  the  following 
from  the  Engineering  Record,  July  18, 1896,  will  be  of  interest :  — 

"  The  report  was  made  public  last  week  of  Dr.  Chas.  P.  Knapp,  County 
Inspector  of  the  Pennsylvania  State  Board  of  Health,  of  Wyoming,  Pa.,  who 
in  April  last  investigated  the  water  supply  of  Plymouth,  Pa.,  where  typhoid 
fever  has  been  prevalent  for  some  time  past.  Dr.  Knapp  reported  that  the 
water  of  Plymouth  is  subject  to  contamination  from  a  dairy  farm  on  the  head 
waters  of  the  stream  from  which  the  supply  is  taken.  This  is  the  same  farm- 
house and  stream  to  which  was  traced  in  1885  the  typhoid  epidemic  in  Plym- 
outh, when  there  were  1,500  cases  and  150  deaths."* 

*  The  cases  and  deaths  from  this  epidemic  have  been  differently  reported  by  different 
authorities. 


96  THE  PURIFICATION  OF  WATER. 

ZURICH,  SWITZERLAND. 

"  In  the  spring  of  1884,  Zurich  was  visited  by  a  virulent  outbreak  of 
typhoid  fever,  which,  beginning  in  the  month  of  March,  reached  its  maximum 
intensity  in  April,  and  practically  disappeared  by  the  end  of  June,  fully  two 
per  cent  of  the  population  having  been  attacked  and  nine  per  cent  of  the 
cases  proving  fatal.  The  Commission  appointed  to  inquire  into  the  cause  of 
this  epidemic  arrived  at  the  conclusion  that  the  infection  could  not  be  traced 
to  abnormal  meteorological  or  sanitary  conditions ;  but  that  the  filtered  Lim- 
mat  water,  although  clear  and  chemically  satisfactory,  contained  an  abnormal 
quantity  of  bacteria.  It  was  subsequently  discovered  that,  owing  to  the  dredg- 
ing operations  in  connection  with  the  new  quay-works,  the  impure  matter 
deposited  at  the  bottom  of  the  river  had  been  stirred  up,  and,  not  being  effec- 
tually retained  by  the  submerged  filter-bed,  had  found  its  way  into  the  con- 
crete main,  which  was  by  no  means  water-tight,  and  had  been  damaged  during 
the  blasting  and  removal  of  an  erratic  block  from  the  bed  of  the  Limmat. 
The  reason  why  the  defective  condition  of  both  filter-bed  and  conduit  did  not 
arouse  suspicion  until  after  the  outbreak  of  the  epidemic  was  twofold,  —  first, 
the  Limmat  water  was  generally  so  clear  and  chemically  pure  that  filtration 
was  considered  of  altogether  secondary  importance  ;  and,  secondly,  the  per- 
meability of  the  concrete,  laid  at  2  to  3  meters  depth  below  the  river  bed,  was 
regarded  as  an  advantage  rather  than  a  defect,  inasmuch  as  the  sand  in  which 
the  conduit  was  imbedded  was  supposed  to  act  as  a  'filtering  medium.  The 
bacteriological  investigations,  in  conjunction  with  the  proved  percolation  of 
impure  matter  through  the  filter  and  conduit,  stamped  the  Limmat  water  as  the 
vehicle  of  infection.  .  .  .  Hence,  at  Zurich,  the  necessity  was  promptly  rec- 
ognized of  providing  an  entirely  new  water  supply  for  the  town  and  suburbs."* 

(The  submerged  filter  mentioned  above  has  been  experimented 
with  by  several  cities  in  this  country.  It  is  a  filter  constructed  in 
the  bed  of  the  river,  of  such  materials  as  may  be  convenient,  with 
no  provisions  for  cleaning  or  renewal  of  the  filtering  materials. 
Such  filters,  wherever  used  within  the  author's  knowledge,  have 
been  failures  as  sanitary  devices.) 

SPRING  WATER,  N.Y. 

Spring  Water  in  1889  was  a  village  of  600  population,  situated 
two  and  one-half  miles  south  of  Hemlock  Lake,  which  constitutes 
the  source  of  water  supply  for  Rochester,  N.Y.  This  village  was 
on  the  watershed  of  the  lake,  and  typhoid  fever  occurring  there 

*  Preller  on  the  Zurich  Water  Works,  London,  1892,  p.  7. 


CITATIONS   ON   TYPHOID   FEVER  EPIDEMICS.  97 

was  a  menace  to  the  health  of  the  larger  comrnunity.  The  water 
supply  of  the  village  was  obtained  from  open  and  driven  wells 
sunk  a  short  distance  into  the  drift. 

A  so-called  endemic  of  typhoid  fever,  which  occurred  in  this 
village  during  October  and  November  of  that  year,  was  made  the 
subject  of  careful  investigation  by  Mr.  George  W.  Rafter  (then 
assistant  engineer  of  the  Rochester  Water- Works)  and  Dr.  M.  L. 
Mallory.  The  following  information  is  taken  from  the  Report  of 
these  gentlemen  to  the  chief  engineer  of  the  water-works  :  — 

"  The  earliest  clearly  defined  case  of  typhoid  fever  we  found  to  be  that  of 
...  a  boy  thirteen  years  of  age,  who,  when  taken  sick  with  the  disease  on 
Sept.  29,  was  employed  at  Snyder's  Hotel.  .  .  .  Not  only  is  the  well  at  this 
place  in  close  proximity  to  the  privy  (thirty  feet  away),  but  half-way  between 
the  well  and  the  privy  we  found  a  board  slop  drain,  which  undoubtedly  dis- 
charges into  the  well  a  considerable  portion  of  its  contents.  The  family 
claimed,  however,  that  the  water  of  this  well  had  been  considered  bad  for  a 
year  and  a  half,  and  none  of  it  had  been  used  for  domestic  purposes  during 
that  time ;  the  water  so  used  having  been  all  obtained  from  the  well  on  the 
adjoining  premises.  .  .  .  We  found  the  pump  in  working  order,  with  pail 
beneath  the  spout  partly  filled  with  water,  and  with  a  dipper  in  the  pail.  On 
questioning  the  servant  girl,  it  appeared  very  evident  that  the  water  was  some- 
times used.  .  .  . 

"  Our  view  as  to  the  origin  of  these  cases  of  typhoid  fever  in  the  village 
.  .  .  is  therefore  as  follows:  The  hotel  was  certainly  an  original  center  of 
infection  as  ...  four  persons  living  there  were  taken  sick  with  the  disease ; 
and  while  we  are  unable  to  establish  the  fact  definitely,  we  consider  it  very 
probable  that  some  '  walking '  case  of  typhoid  fever  stopped  at  the  hotel,  and 
.  .  .  inoculated  the  hotel  privy  with  germs  of  typhoid  contained  in  the  dejec- 
tions. The  chemical  analyses  of  the  water  of  the  hotel  well,  .  .  .  and  the 
bacteriological  examinations,  both  show  the  water  to  be  exceedingly  bad, 
unfitted  for  domestic  use,  and  the  environment  such  as  to  lead,  with  the  cer- 
tainty of  a  mathematical  demonstration,  to  the  conclusion  that  there  is  gross 
pollution  from  the  privy  and  slop  drain." 

The  village  of  Spring  Water  at  the  time  of  this  outbreak  had  a 
population  of  600,  of  which  20  were  attacked  with  typhoid  fever. 
"  The  soil  upon  which  the  village  stands  is  of  an  open,  pervious 
character  for  a  depth  of  10  to  20  feet,"  while  the  wells  (open  and 
driven)  had  a  depth  of  10  to  18  feet.  Previous  to  this  attack 
of  typhoid  fever  the  village  had  a  record  of  being  an  unusually 
healthful  locality. 


98  THE  PURIFICATION  OF   WATER. 

It  is  stated  in  the  report  that  the  Eberth  bacillus  (b.  typhosus) 
was  found,  upon  examination  by  Dr.  H.  C.  Ernst  of  Harvard  Uni- 
versity, in  a  sample  of  water  from  one  of  the  wells  supposed  to 
have  been  concerned  in  spreading  the  infection. 

The  admixture  of  filth  and  drinking-water,  which  was  assumed 
to  have  been  the  secondary  cause  of  this  epidemic,  is  going  on  on 
a  very  large  scale  all  over  the  land,  with  this  difference,  however, 
that  in  Spring  Water  the  mixing  was  done  right  on  the  premises 
of  the  citizens,  while  the  plan  usually  pursued  is  to  pollute  the 
water  supply  of  one  city  with  the  sewage  of  another.  Will  a  time 
arrive  when  there  will  be  a  law  on  the  Federal  statute  book  which 
will  give  the  Engineer  Corps  of  the  War  Department  full  power 
to  prevent  the  sewage  pollution  of  all  navigable  streams  and  bodies 
of  water  under  its  control,  and  when  all  water  craft  will  be  com- 
pelled to  dispose  of  their  sewage  and  garbage  in  some  other  man- 
ner than  by  dumping  it  ad  libitum  into  these  rivers  and  lakes, 
which  constitute  the  sources  of  water  supply  for  so  many  populous 
cities  and  towns? 

LOWELL,  MASS. 

During  the  autumn  and  winter  of  1890-1891,  the  city  of 
Lowell,  Mass.,  was  visited  with  a  severe  epidemic  of  typhoid  fever, 
which  had  its  origin  in  two  or  three  cases  of  typhoid  fever  in  a 
small  manufacturing  village  (North  Chelmsford)  situated  on  Stony 
Brook,  a  small  stream  which  flowed  into  the  Merrimac  River 
about  three  miles  above  the  Lowell  Water- Works  intake.  Within 
due  time  after  typhoid  developed  at  Lowell,  the  city  of  Lawrence, 
on  the  Merrimac  River  about  nine  miles  below  Lowell,  was  also 
stricken  with  typhoid  fever.  The  city  of  Lowell  discharges  its 
sewage  into  the  river  below  the  city,  while  the  city  of  Lawrence 
below  draws  its  water  supply  from  the  river  after  it  has  been 
polluted  by  the  Lowell  sewage. 

Thus  from  Stony  Brook  the  disease  was  traced  to  Lowell,  and 
from  Lowell  to  Lawrence.  Stony  Brook  was  inoculated  through 
the  use  of  wooden  privies  overhanging  and  discharging  the  fecal 
matter  into  the  stream,  which  in  turn  carried  the  bacillus  of  typhoid 
into  the  Merrimac  River,  from  which  it  was  pumped  into  the  Lowell 


CITATIONS  ON   TYPHOID  FEVER  EPIDEMICS.  99 

reservoir,  and  distributed  to  the  citizens  through  the  public  water 
mains.  The  fecal  discharges  of  the  typhoid  patients  at  Lowell 
went  into  the  sewers  ;  these  in  turn  inoculated  the  river  below  that 
city,  and  furnished  the  infection  to  the  sister  city  of  Lawrence, 
which  pumped  the  typhoid-infected  water  to  its  reservoir,  and  like 
Lowell,  supplied  it  to  its  citizens  through  the  public  water  mains. 

Very  careful  investigations,  conducted  by  Professor  W.  T. 
Sedgwick,  biologist  to  the  State  Board  of  Health  of  Massachusetts, 
clearly  established  the  origin  of  the  epidemic  among  the  people 
living  on  Stony  Brook,  and  its  carriage  to  the  cities  of  Lowell  and 
Lawrence  through  the  medium  of  the  public  water  supply.* 

SAULT  STE.  MARIE,  MICH. 

"  The  city  of  Sault  Ste.  Marie  takes  its  water  supply  above  the  rapids, 
and  ordinarily  it  is  very  pure  water.  In  the  fall  of  1890,  owing  to  a  break  in 
the  lock,  more  than  two  hundred  boats  were  detained  for  two  days  above  the 
lock  and  in  the  immediate  vicinity  of  the  intake.  Some  ten  days  later  typhoid 
fever  appeared,  and  the  deaths  were  reported  to  be  not  less  than  thirty.  All 
the  cases  appeared  within  a  few  weeks,  and  sample  (analysis  below)  was  taken 
at  this  time."  f 

ANALYSIS  OF   WATER   FROM   SAULT   STE.    MARIE. 

SOURCE.  —  LAKE   MICHIGAN. 


PARTS  PER  100,000. 

BACTERIA. 

PER  C.  C. 

KIND  OF 
BACTERIA  FOUND. 

Free  Ammonia. 

Albuminoid. 

Chlorine. 

0.0224 

0.0168 

0.33 

2,000 

B.   Venensous. 

This  water  was  regarded  as  the  cause  of  typhoid  fever  ;  and 
b.  venenosus,  according  to  Dr.  Vaughan,  is  classed  as  a  pathogenic 
organism.  "  One  drachm  of  a  bouillon  culture,  twenty-four  hours 
old,  injected  into  the  abdominal  cavity  of  a  rat,  produced  death." 

ST.   Louis,  Mo. 

During  the  year  1892-1893,  the  city  of  St.  Louis,  Mo.,  U.S.A., 
had  an  unusual  case  and  death  rate  from  typhoid  fever,  the  annual 
mortality  from  this  disease  rising  from  34  to  103  per  100,000  of 
population  living. 

*  Report  Massachusetts  State  Board  of  Health,  1892,  p.  668. 

t  A  Bacteriological  Study  of  Drinking  Water,  by  Victor  C.  Vaughan,  Ph.D.,  M.D.,  Ann 
Arbor,  Mich.,  1892,  pp.  8-12. 


100  THE   PURIFICATION  OF   WATER. 

A  careful  investigation  by  the  public  health  department  re- 
vealed the  fact  that  in  those  districts  of  the  city  where  the  water 
from  the  public  mains  was  not  generally  used  for  drinking-pur- 
poses,  the  citizens  were  almost  wholly  exempt  from  the  infection, 
and  that  with  few  exceptions  the  cases  were  all  confined  to  a  dis- 
trict the  people  of  which  drew  all  or  part  of  their  drinking-water 
from  the  public  mains.*  The  water  supply  of  St.  Louis  is  obtained 
by  pumping  from  the  Mississippi  River,  and  the  only  purification 
attempted  is  to  allow  24  to  36  hours  for  sedimentation  in  several 
low-level  reservoirs. 

ELMIRA,  N.Y. 

This  city  was  visited  by  an  epidemic  of  typhoid  fever  during 
January  and  February  of  1896,  the  cause  of  which  was  carefully 
inquired  into  by  Professor  Olin  H.  Landreth  of  Schenectady,  N.Y. 
From  his  very  complete  report  the  following  facts  are  gleaned  :  — 

Elmira  is  situated  on  the  Chemung  River,  with  a  population  at 
the  time  of  the  epidemic  of  37,500.  In  the  cities  and  villages 
above  Elmira,  on  the  river  and  its  tributaries,  and  within  a  reach 
of  50  miles,  an  aggregate  population  of  40,000  is  found,  among  less 
than  three-fourths  of  which  70  cases  of  typhoid  fever  were  reported 
to  have  occurred  prior  to  the  outbreak  or  increase  in  the  typhoid 
rates  at  Elmira. 

Of  this  number  six  cases  were  on  premises  which  sewered  to 
the  river,  and  "  a  larger  number  with  less  definite  but  equally 
direct  connection  with  the  river."  According  to  the  report,  the 
time  required  for  the  passage  of  sewage  from  the  most  remote 
point,  where  previous  cases  of  typhoid  had  been  recorded,  to  the 
water-works  intake  at  Elmira,  would  be  but  a  few  hours. 

During  December  (1895),  there  had  been  fifteen  days  of  con- 
tinuous cold  weather,  followed  late  in  the  month  by  heavy  rains 
which  caused  a  freshet  in  the  river,  and  carried  down  with  the  run- 
off of  rainfall  considerable  polluting  matter  collected  on  the 
frozen  ground. 

The  epidemic  of  typhoid  in  Elmira  followed  the  flood  in  the 
Chemung  River. 

*  Annual  Report  of  Health  Commissioner,  1892-93,  p.  120. 


CITATIONS  ON  TYPHOID  FEVER  EPIDEMICS.  101 

~~  f 

Samples  of  water  from  the  river  at  the  intake  of  the  Elmira 
Water- Works,  sixteen  miles  below  the  nearest  .point  of  sewage  pol- 
lution, taken  Dec.  28,  1895,  and  Jan.  21,  1896,  gave  from  45,000 
to  1,080  bacteria  per  cubic  centimeter,  among  whicJi  was  found  tJie 
colon  bacillus.  The  larger  number  of  bacteria  per  cubic  centimeter 
of  water  was  found  while  the  river  was  in  flood  or  directly  after ;  a 
condition  often  noticed  in  connection  with  rivers  subject  to  a  wide 
range  of  flow.  Aside  from  the  very  large  number  of  bacteria 
found  at  the  earlier  date  of  examination,  there  were  other  unmis- 
takable evidences  of  sewage  pollution  of  the  water. 

Search  for  the  typhoid  bacillus  failed  to  reveal  its  presence  in 
the  water ;  but  this  is  not  surprising,  for  we  fail  to  find  it  even 
under  much  more  favorable  conditions,  and  the  failure  to  find  it 
is  only  negative  evidence  that  it  is  not  in  the  water. 

After  a  careful  review  of  all  the  facts  bearing  upon  the  epi- 
demic, Professor  Landreth  reached  the  following  conclusions  :  — 

1.  The    milk    supply   was    in    no    way   responsible    for   the 

epidemic. 

2.  The  city  water  supply  was  unquestionably  the  means  by 

which  the  infection  was  introduced  and  the  epidemic 
originated. 

3.  The  city  water  supply  was,  in  all  probability,  infected  by 

the  typhoid  bacillus  from  the  Chemung  River  from  cases 
occurring  up-stream  during  the  summer  or  fall  of  1895. 

4.  The  city  water  supply  as  now  taken  from  the  collecting 

gallery  is  quite  probably  liable  to  infection  at  any  time 
from  the  occurrence  of  typhoid  fever  cases  near  the 
gallery,  in  unsewered  premises,  through  the  medium  of 
the  ground  water,  and  may  already  have  suffered  such 
infection. 

5.  A  number  of  cases  of  fever  during  the  latter  stages  of  the 

epidemic  are  due  to  secondary  infection  from  adjacent 
previous  cases,  largely  through  the  medium  of  wells 
infected  from  vaults  and  cesspools. 

6.  Well  water  should  be  very  thoroughly  boiled  before  being 

considered  safe  for  use.  It  is  now  more  liable  to  infec- 
tion than  river  water. 


102  THE   PURIFICATION  OF   WATER. 

PARIS,  FRANCE. 

In  Popular  Science  for  December,  1895,  Mr.  Stoddard  Dewey 
is  authority  for  the  following  statement :  — 

"  In  the  French  army  stationed  at  Paris  in  1888,  there  were  824  cases  of 
typhoid  fever,  and  in  1889,  1,179  cases  of  typhoid  fever.  During  this  time  the 
army  had  been  drinking  the  sewage-polluted  water  of  the  River  Seine.  In 
1889  the  water  of  the  River  Vanne  was  substituted  for  that  of  the  Seine, 
when  the  number  of  cases  for  the  next  four  years,  1890-1893  inclusive,  was 
reduced  to  299,  276,  293,  and  258.  Through  an  accident  the  water  of  the 
Vanne  became  contaminated,  and  for  the  next  three  months  the  cases  rose  to 
436.  The  Vanne  again  became  comparatively  free  from  contamination;  and 
for  the  next  four  months  of  1895,  but  eight  cases  in  all  occurred,  and  these 
were  charged  to  some  other  water  than  that  of  the  River  Vanne." 

SAN  FRANCISCO,  CAL. 

The  investigation  of  the  public  water  supply  of  this  city  in  its 
relation  to  typhoid  fever,  by  Dr.  M.  J.  Rosenau,  has  been  men- 
tioned in  a  previous  chapter ;  and  in  order  to  appreciate  the  full 
force  of  the  facts  disclosed,  the  following  brief  description  of  the 
sources  of  supply  is  quoted  from  the  official  report  to  the  Super- 
vising Surgeon-General,  U.  S.  M.  H.  S. 

"  The  Spring  Valley  Water  Company  furnishes  San  Francisco  most  of  its 
water.  Its  principal  source  is  from  three  catch  basins,  made  by  damming 
conveniently  shaped  valleys,  between  12  and  20  miles  from  the  city,  in  San 
Mateo  County.  These  three  reservoirs  are  known,  respectively,  as  Crystal 
Springs,  San  Andreas,  and  Pilarcitos.  From  each  a  pipe-line  leads  to  the 
city,  thus  making  three  water  districts.  These  districts  are  irregularly  shaped, 
and  discontinuous,  owing  to  engineering  difficulties.  These  three  systems  are 
connected  in  such  a  manner  that  the  water  from  any  one  reservoir  may  be 
pumped  to  either  of  the  other  two  districts.  This  fact  negatives  the  impor- 
tance of  regarding  the  districts  as  separate,  from  a  sanitary  standpoint.  Smaller 
reservoirs  in  the  city  are  used  more  for  the  purpose  of  storage  in  case  of  sud- 
den increased  demand,  by  fire,  or  from  accident,  than  for  obtaining  pressure. 
The  flow  is  continuous. 

"The  Visitacion  Water  Company  supplies  about  600  consumers  in  the 
southern  section  of  the  city.  The  source  of  this  water  is  from  eight  wells  sunk 
in  Bay  View  Valley,  on  the  outskirts  of  the  city.  Six  of  these  wells  are  150  feet 
deep,  one  is  180,  the  other  130  feet  through  sand  and  gravel.  The  wells  do  not 
flow  spontaneously,  and  are  fitted  with  deep-well  pumps.  They  are  known  as 


CITATIONS   ON   TYPHOID   FEVER   EPIDEMICS.  103 

artesian  wells ;  but  as  they  do  not  pass  through  an  imp'ervious  stratum,  they 
do  not  comply  with  the  original  meaning  of  that  term. 

"  IVells.  —  From  the  best  information  at  my  command,  there  are  very  few 
private  wells  for  drinking  and  household  purposes  in  the  city." 

The  usual  methods  for  collecting  and  planting  water  samples 
were  followed,  the  samples  b'eing  taken  from  taps  in  houses.  All 
water  was  collected  by  Dr.  Rosenau,  with  the  usual  precautions  to 
insure  a  proper  sample,  and  to  avoid  the  introduction  of  adventi- 
tious organisms.  "  Special  care  was  exercised  to  select  a  tap  that 
led  directly  from  the  mains."  Fermenting  organisms  were  iso- 
lated by  the  fermentation  tube,  according  to  the  method  proposed 
by  Dr.  Theobald  Smith. 

"  In  several  instances  the  colon  bacillus  was  isolated  by  planting  \  cubic 
centimeter  of  the  suspected  water  directly  upon  Wurtz  milk-sugar  litmus  agar, 
and  growing  the  plants  at  41°.5-42°  C.  This  slight  modification  of  Smith's 
method  has  proven  useful,  not  only  for  isolating  suspicious  organisms,  but  it 
is  believed  it  may  be  used  to  give  a  proximate  idea  of  their  number  to  the 
cubic  centimeter. 

"  In  case  the  above  methods  failed  to  find  fermenting  organisms,  the 
water  was  further  studied  upon  gelatin  and  glycerin  agar,  with  the  result 
that,  in  seven  samples,  eight  suspicious  organisms  were  found.  These  all 
proved  to  be  forms  belonging  to  the  group  of  proteus,  and  resembling  b.  pro- 
teus vulgaris.  They  all  grew  well  at  room  temperature,  also  at  37°,  but  not 
at  41°.5  C." 

Thirty-six  samples  of  water  collected  from  widely  separated 
points  were  examined  between  Dec.  4,  1895,  and  Feb.  7,  1896. 

"  Fermenting  organisms  were  isolated  from  14  of  the  36  samples ;  8  of 
these  14  contained  proteus,  and  the  remaining  6  the  colon  bacillus.  ...  In  the 
San  Andreas  water,  both  the  colon  bacillus  and  proteus  were  found.  In 
the  Pilarcitos  water  also,  both  proteus  and  the  colon  organisms  were  isolated. 
In  the  Crystal  Springs  water,  only  an  occasional  proteus  was  met  with.  The 
greater  freedom  from  fermenting  organisms  enjoyed  by  this  water  is  in  accord 
with  the  control  of  the  watershed,  and  indicates  what  may  be  accomplished 
in  preventing  contamination  of  the  water  by  excluding  all  habitation  from  the 
water  basin.  The  Visitation  (deep  well)  water  was  found  to  contain  the 
colon  bacillus" 

Concerning  tbe  colon  bacillus,  the  Report  quotes  a  paragraph 
from  Dr.  Abbott  *  which  is  worthy  of  reproduction  here. 

*  The  Principles  of  Bacteriology,  by  A.  C.  Abbott,  M.D.,  Philadelphia,  1894,  p.  422. 


104  THE  PURIFICATION  OF   WATER. 

"  In  the  normal  intestinal  tract  of  all  human  beings  and  many  other  mam- 
mals, as  well  as  associated  with  the  specific  disease  producing  bacterium  in 
the  intestines  of  typhoid  fever  patients,  is  an  organism  that  is  frequently  found 
in  polluted  drinking-waters,  and  whose  presence  is  proof  positive  of  pollution 
by  either  normal  or  diseased  intestinal  contents  ;  and  though  efforts  may  result 
in  failure  to  detect  the  specific  bacillus  of  .typhoid  fever,  the  finding  of  the 
other  organism,  the  bacterium  coli  communis,  justifies  one  in  expressing  the 
opinion  that  the  water  under  consideration  has  been  polluted  by  intestinal 
evacuations  from  either  human  beings  or  animals.  Waters  so  located  as  to  be 
liable  to  such  pollution  can  never  be  considered  as  other  than  a  continuous 
source  of  danger  to  those  using  them." 

To  which  Dr.  Rosenau  adds,  "  This  organism  was  found  in 
samples  from  San  Andreas,  Pilarcitos,  and  Visitacion." 

"  The  fact  that  the  colon  bacillus  was  more  readily  isolated  from  the 
water  after  the  heavy  rains,  and  that  fermentation  was  also  more  frequent 
after  the  heavy  rains  than  before,  would  indicate  soil-washings  as  one  of  the 
sources  of  this  organism  in  the  water ;  but  that  its  presence  in  the  water  is  not 
alone  the  result  of  soil-washings  of  pasture  lands  is  indicated  by  a  study  of  the 
typhoid  fever  records.  Typhoid  fever  is  a  constant  factor  in  San  Francisco, 
and  a  study  of  (the  relation  of)  the  death  rate  from  this  disease  to  (the)  rainfall 
shows  a  striking  coincidence  in  several  years ;  i.e.,  a  marked  rise  in  deaths 
following  the  first  heavy  rains." 

In  a  table  covering  the  period  July,  1882,  to  June,  1895,  inclu- 
sive, Dr.  Rosenau  has  given  in  parallel  columns  the  total  monthly 
rainfall  and  deaths  from  typhoid  fever,  from  which  the  diagram 
on  the  opposite  page  has  been  drawn. 

Referring  to  the  diagram,  which  gives  the  totals  of  rainfall  and 
deaths  from  typhoid  fever  for  fourteen  years,  it  does  not  appear 
that  the  higher  typhoid  rates  are  always  coincident  with  the  higher 
rates  of  rainfall.  In  fact,  the  death  rate  fourth  in  magnitude  for 
this  interval  of  time  occurred  during  the  month  of  least  rainfall 
(August).  Generally,  however,  the  curve  of  typhoid  fever  deaths 
declines  with  the  curve  of  rainfall,  and  rises  before  the  period  of 
high  precipitation  begins. 

DENVER,  COL. 

During  the  past  year  (1896),  the  typhoid  rates  being  higher 
than  usual,  an  investigation  of  the  probable  causes  was  instituted 


CITATIONS   ON  TYPHOID  FEVER  EPIDEMICS. 


105 


by  the  health  commissioner,  with  the  result  that  the  public  water 
supply  was  held  accountable  for  the  increase  of  the  case  and  death 
rates  for  this  disease.* 


Inches  of  Rainfall  for  14  Years. 
By  Months. 


Fig.  2.     Totals  of  Rainfall  and  Deaths  from  Typhoia  Fever,  for  a  Period  of  14  Years,  San 
Francisco,  Cat.,  from  January,  1882,  to  December,  1895. 

(From  Notes  in  Dr.  Rosenarfs  Report  on  City  Water  Supply.) 

The  Report  contains  a  table  of  the  deaths  from  typhoid  fever 
for  the  years  1892  to  1896  inclusive,  for  the  months  of  June  to 

*  Preliminary  Report  of  the  Health  Commissioner  to  the  Mayor,  Denver,  Oct.  12, 1896. 


106  THE   PURIFICATION  OF   WATER. 

September,  from  which  the  months  of  July,  August,  and  Septem- 
ber, are  reproduced  below  :  — 

DEATHS   FROM    TYPHOID   FEVER. 
YEAR,  1892.  1893.  1894.  1895.  1896. 

July,  28326 

August,  12               4               8               5             13 

September,  9               5               8               8             28 

Total,  23             17             19             15             47 

Commenting  upon  this  the  health  commissioner  says :  — 

"  Is  it  to  be  wondered  at  that  such  an  increase  of  typhoid  fever  prevalence 
in  a  few  weeks  should  have  called  attention  to  the  water  supply?  Investiga- 
tion of  the  location  of  the  cases  showed  that  they  were  fairly  well  distributed 
throughout  the  city;  and  so  far  as  could.be  determined  there  was  no  local 
cause  operative  in  any  part  of  the  city  to  cause  this  disease,  nor  was  there 
any  one  possible  cause  of  infection  common  to  all  those  affected  except  the 
water  they  drank.  .  .  ." 

"  We  know  that  when  a  certain  small  percentage  of  cases  due  to  local  in- 
fection of  milk  or  other  food,  or  contracted  by  nurses,  is  eliminated,  the  great 
bulk  of  cases  of  typhoid  fever  in  all  epidemics  is  due  to  the  one  common  cause, 
—  an  infected  water  supply.  When  the  probable  sources  of  that  infection  are 
discovered,  it  is  the  plain  duty  of  those  upon  whom  the  responsibility  lies  to 
suggest  the  remedies.  Failure  to  adopt  the  remedial  measures  that  are  neces- 
sary, means  deliberate  acceptance  of  responsibility  for  the  resultant  loss  of 
human  life." 

The  city  of  Denver  has  two  distinct  sources  of  water  supply,  — 
one  from  the  Platte  River,  and  the  other  from  an  artificial  reser- 
voir called  Marston  Lake,  the  latter  source  being  fed  from  moun- 
tain streams.  Both  sources  were  found  by  the  health  officials  to 
be  exposed  to  sewage  pollution  ;  and  although  it  was  claimed  that 
the  water  of  the  river  and  lake  was  filtered  before  it  was  delivered 
to  the  consumers,  the  Report  indicates  that  this  was  wholly  inef- 
fectual, and  not  calculated  to  improve  its  quality. 

MlDDLETOWN,    CONN. 

This  was  an  epidemic  of  typhoid  caused  by  oysters  which  had 
been  fattened  in  Quinepiac  River,  near  the  mouth  of  a  private 
drain  or  sewer,  from  premises  where,  during  the  time  the  oys- 


CITATIONS   ON  TYPHOID  FEVER  EPIDEMICS.  107 

ters  were  planted,  two  cases  of  typhoid  fever  Mad  occurred.  The 
epidemic  followed  a  banquet  or  supper  given  in  the  autumn  of 
1894  by  two  of  the  societies  of  Wesleyan  College,  at  which  some 
of  the  students  indulged  in  the  oysters  raw,  while  the  others  ate 
only  cooked  oysters.  The  students  who  ate  raw  oysters  were  the 
only  ones  affected. 

The  oysters  had  been  taken  from  distant  beds,  and  replanted 
in  this  little  stream  for  the  purpose  of  "  plumping"  them  by  hav- 
ing a  current  of  fresh  water  run  over  them  during  ebb  tides.  The 
current  of  fresh  water  in  this  case  was  probably  charged  with  the 
germs  of  typhoid  fever  from  the  two  cases  mentioned  above. 
The  reports  on  the  epidemic  indicate  that  the  oysters  had  not 
been  planted  at  the  mouth  of  the  sewer  for  any  great  length  of 
time  before  they  were  taken  up  for  sale ;  but,  considering  the  oys- 
ter as  a  natural  scavenger  of  the  organic  matter  in  sewage,  this 
time  was  altogether  sufficient  for  the  absorption  of  some  of  the 
sewage  and  disease  germs  from  the  sewer  which  discharged  into 
the  river  just  above  the  oyster-bed. 

The  students  who  ate  only  cooked  oysters  escaped  infection, 
the  cooking  being  sufficient  to  sterilize  the  oysters  and  such  liquid 
as  was  contained  in  the  shells. 

In  this  instance  the  dejections  of  the  original  typhoid  patients 
were  thrown  into  the  sewer,  and  the  sewer  discharged  into  the 
river  about  three  hundred  feet  above  the  oyster-bed.  The  typhoid 
germs  were  absorbed  by  the  oysters,  and  the  oysters  were  ab- 
sorbed by  the  students,  with  the  usual  result  in  such  cases,  that 
typhoid  fever  reappeared  among  the  students  who  ate  the  unster- 
ilized  oysters. 

STAMFORD,  CONN. 

;'  There  has  been  considerable  alarm  at  Stamford,  Conn.,  over  an  epidemic 
of  typhoid  fever.  Over  160  cases  appeared  in  a  short  time,  and  the  investiga- 
tion of  the  State  Board  of  Health  showed  that  all  were  on  the  route  of  one 
milk-seller.  The  investigators  came  to  the  conclusion  that  impure  milk  was 
the  source  of  the  disease.  The  milkman  bought  his  milk  from  farmers  about 
Stamford  ;  but  as  these  farmers  also  sold  their  milk  to  other  persons  who  were 
not  reported  ill,  it  was  evident  that  the  germs  entered  the  milk  after  it  came 
into  the  possession  of  the  retailer. 


108  THE  PURIFICATION  OF   WATER. 

"  It  was  found  that  the  milkman  washed  his  cans  in  water  from  a  well  on 
his  premises,  which,  upon  being  analyzed,  proved  to  be  totally  unfitted  for 
drinking-purposes,  and  dangerous  to  use.  This  case,  like  the  Montclair  epi- 
demic, .  .  .  shows  that  an  infected  milk  supply  may  be  answerable  for  many 
typhoid  outbreaks  which  are  not  chargeable  to  a  water  supply."  * 

The  mass  of  evidence  on  the  cause  of  typhoid  fever  abroad  and 
in  this  country  is  to  the  effect  that  it  is  a  water-carried  disease ; 
and  even  in  those  epidemics  where  (as  at  Stamford,  Conn.,  April, 
1895,  and  Montclair,  N.J.,  April,  1894)  milk  was  the  immediate 
distributer  of  the  germ,  water  used  in  connection  with  the  dairy 
operations  has  been  the  carrier  of  the  typhoid  bacillus.  From 
which  it  follows,  that  if  the  typhoid  organism  is  kept  out  of  our 
water  supplies,  typhoid  fever  would  cease  to  exist  as  a  scourge  of 
the  youth  and  promise  of  our  land.f 

ELIZABETH,  N.  J. 

"  Typhoid  fever  has  become  epidemic  here,  over  fifty  cases  having  been 
reported;  and  a  joint  investigation  by  the  Local  and  State  Boards  of  Health 
is  probable.  To  the  use  of  polluted  water  is  attributed  the  outbreak."  J 

"  There  is  a  marked  increase  in  the  number  of  typhoid  fever  cases  in 
this  city.  Not  less  than  forty  cases  are  now  being  treated  by  the  doctors, 
and  four  deaths  have  occurred,  all  the  victims  being  adults."  § 

"  E M ,  aged  thirteen,  died  to-day  of  typhoid  fever  at  the  Alexian 

Hospital.  It  is  the  fifth  fatal  case  during  the  epidemic.  His  home  was  on 
Rahway  Avenue,  where  the  disease  prevails,  and  where  polluted  wells  were 
discovered.  Nine  cases  are  in  the  Elizabeth  General  Hospital,  and  House 
Physician  Whitehead  is  ill,  with  symptoms  of  typhoid."  || 

EVANSVILLE,   IND. 

«  Dr.  Metcalf,  of  the  Indiana  State  Board  of  Health,  has  been  in  Evans- 
ville  to  examine  into  the  cause  for  the  prevalence  of  typhoid  fever.  There  are 
one  hundred  cases  of  this  disease  reported  by  the  local  physicians.  Dr.  Met- 
calf accepted  the  opinion  shared  by  the  physicians  that  impure  water,  more 
than  anything  else,  was  at  fault.  Two  of  the  largest  sewers  empty  into  the 
Ohio  River,  from  which  the  water  supply  is  taken  near  the  city  water-works."  ** 

*  Engineering  Record,  May  11,  1895.  §  New  York  Times,  Aug.  21,  1894. 

f  Fire  and  Water,  Sept.  22,  1894.  ||  New  York  Times,  Sept.  2,  1894. 

\  New  York  Times,  Aug.  20,  1894.  **  Fire  and  Water,  May  11, 1895. 


CITATIONS   OF   TYPHOID  FEVER   EPIDEMICS.  109 

Thirty-five  thousand  deaths  a  year  in  the 'large  cities  of  the 
United  States  are  said  to  be  due  to  typhoid  fever  alone,  a  disease 
the  causes  of  which  are  fully  understood,  and  which  sanitarians 
declare  is  entirely  preventable.  The  mischief-making  germ  is 
usually  taken  into  the  system  in  drinking-water,  which  has  been 
contaminated  with  dejecta  from  other  victims  residing  many  miles 
away.  In  some  cases  when  there  is  a  typhoid  epidemic,  the  out- 
break is  traceable  to  the  use  of  water  from  a  well  located  near  cess- 
pools ;  in  others  to  the  common  supply  of  a  town,  either  a  river  or 
a  lake.  To  guard  against  pollution,  cities  should  obtain  control  of 
the  land  around  the  source  of  their  water  supply,  and  by  rigid  reg- 
ulations insure  such  purity  as  sensibly  to  reduce  the  death  rate. 
But  where  such  a  stream  as  the  Mississippi,  or  such  a  lake  as  Michi- 
gan, is  the  reliance  of  any  great  center  of  population,  precautions 
of  this  sort  are  obviously  impracticable.  Hence,  measures  must  be 
taken  either  by  individual  consumers  or  municipal  authorities  to 
sterilize  the  water  supply  whenever  there  is  occasion  for  suspicion.* 

The  difficulty  of  impressing  upon  some  people  the  dangers  of 
a  polluted  water  supply  is  due  to  the  fact  that  the  drinking  of  such 
water  is  not  followed  by  instant  death,  j  But  where  is  the  sub- 
stantial difference  between  death  from  an  instant  cause,  and  after 
two  or  three  or  more  weeks  of  wasting  fever?  The  former  would 
be  preferred  by  most  men.  Because  the  drinking  of  a  polluted 
water  does  not  kill  at  once,  like  a  dose  of  active  poison,  it  is  none 
the  less  a  poison  to  some  susceptible  systems  ;  and  any  corporation 
which,  after  the  fact  of  pollution  is  known,  refuses  to  supply  a  safe 
water  when  a  safe  water  can  be  had,  or  refuses  to  so  deal  with  the 
present  water  as  to  render  it  innocuous  to  health,  is  deserving  of 
the  just  censure  of  a  suffering  public. :f 

The  following  quotation  would  seem  to  indicate  that  this  view 
of  the  matter  is  sometimes  taken :  — 

"  Warren,  Ohio,  won  a  great  victory  over  the  Warren  Water  Company. 
The  judgment  for  $7,621.35,  obtained  by  the  company  against  the  city  in  the 
lower  court  recently,  was  canceled  by  the  Circuit  Court,  which  held  that  the 
company  had  not  furnished  pure  water,  as  bound  to  do  under  its  contract."  § 

*  New  York  Weekly  Tribune,  Oct.  3,  1894.          \  See  Appendix  C. 

f  Fire  and  Water,  Sept.  22,  1894.  §  New  York  Tribune,  Nov.  18, 1894. 


110  THE  PURIFICATION  OF   WATER. 


CHAPTER  VIII. 

SEDIMENTATION   OF   POLLUTED    WATERS. 

EXPERIMENTAL  information  upon  the  influence  of  sedimentation 
on  the  quality  of  water  supplies  is  rather  meager  ;  although  the  fact 
is  well  known  that  sedimentation  for  even  a  few  hours,  with  certain 
waters,  has  a  marked  feect  on  their  appearance,  while  sedimenta- 
tion for  great  lengths  of  time,  according  to  Miquel,  has  wholly 
eliminated  the  evidences  of  organic  matter  and  bacteria  in  the 
water  of  the  River  Seine.  It  is  reasonable  to  suppose  that  in  due 
time  all  organic  matter  in  a  polluted  water,  contained  in  a  subsid- 
ing or  impounding  reservoir,  would  be  appropriated  by  the  bacteria 
of  putrefaction  and  converted  into  ammonia  compounds  ;  and  these, 
then  acted  upon  by  the  nitrifying  organisms,  and  converted  into 
nitrous  and  nitric  acids,  which  uniting  with  the  bases,  such  as  lime, 
magnesia,  soda,  potash,  etc.,  in  the  water,  will  be  precipitated  as 
insoluble  harmless  compounds. 

Such  sedimentation  as  is  really  effective  in  connection  with 
works  of  public  water  supply  is  probably  limited  to  the  precipita- 
tion by  gravity  alone  of  the  suspended  matters  which  give  color 
to  the  water,  such  as  sand,  clay,  and  the  complex  combination  of 
inorganic  and  organic  matter  called  "silt"  Some  chemical  and 
biologic  changes  occur  in  the  water  during  this  precipitation  of 
suspended  matter  by  gravity ;  but  when  the  sedimentation  is 
limited  to  a  few  hours  or  a  few  days,  it  is  doubtful  if  any  marked 
improvement  in  the  quality  has  taken  place. 

Some  improvement  in  color  of  turbid  waters  will  usually  take 
place  within  a  few  hours,  unless  the  color  is  due  to  finely  divided 
peaty  substances,  but  no  change  in  the  organic  matter  or  bacterial 
contents  and  species  will  in  most  instances  occur. 

Sedimentation  of  a  character  which  will  really  affect^ the  hygiene 
of  water  requires  great  length  of  time,  and  should  be  conducted  in 


SEDIMENTATION  OF  POLLUTED    WATERS. 


Ill 


very  large  deep  reservoirs,   which  precludes  an  attempt  at  purifi- 
cation of  polluted  waters  by  sedimentation  alone  by  most  cities. 

The  following  table  contains  the  counts  and  percentages  of  re- 
duction of  bacteria,  in  the  water  of  the  Ohio  River,  for  an  interval 
of  time  not  exceeding  thirty-two  days.  The  Cincinnati  tap  water, 
although  pumped  to  a  distributing  reservoir,  really  has  no  time  for 
sedimentation  before  it  leaves  this  reservoir  and  is  used  by  the 
consumers  ;  while  the  Covington,  Ky.,  reservoirs  are  of  such  ca- 
pacity in  relation  to  the  daily  consumption,  that  usually  there  is 
about  one  month's  time  allowed  for  subsidence  before  the  water 
passes  from  the  reservoirs  to  the  consumers. 

REDUCTION   OF    BACTERIA   BY   SUBSIDENCE.* 


DATE  OF 
INOCULATION. 

DAYS  OF 
GROWTH  ON 
GELATIN. 

BACTERIA 
PER  C.  C.  OF  WATER. 

PERCENTAGE 
OF  BACTERIA 
IN  COVINGTON 
WATER. 

REDUCTION  BY 
SEDIMENTATION. 

PER    CENT. 

Cincinnati. 

Covington. 

1896 
Jan.    17, 

5 

1,472 

272 

18.50 

81.50 

"     23, 

4 

1,599 

194 

12.13 

87.87 

"     28, 

4 

5,002 

172 

3.39 

96.61 

"     28, 

4| 

182 

3.59 

96.41 

Feb.    4, 

4| 

1,656 

53 

3.20 

96.80 

"       4, 

6 

2,042 

56 

2.74 

97.26 

"       8, 

n 

1,561 

63 

4.04 

95.96 

"     11, 

*i 

1,526 

75 

4.95 

95.05 

"     17, 

7 

684 

20 

2.92 

97.08 

"     21, 

4 

329 

26 

7.90 

92.10 

"     21, 

7 

1,232 

112 

9.09 

90.91 

"     26, 

3} 

1,144 

84 

7.34 

92.66 

"     26, 

5 

1,436 

102 

7.10 

92.90 

The  numbers  of  bacteria  and  percentage  of  reduction  in  the 
Covington  water  were  at  times  very  gratifying,  and  indicate  what 
may  be  expected  in  situations  where  the  water  can  be  carried  in  a 
quiescent  state  in  large  reservoirs  for  several  months  before  it  is 
drawn  off  for  use. 

According  to  Professor  Percy  Frankland,  the  average  number 
of  bacteria  in  the  two  streams  which  discharge  into  the  Loch  Lin- 
thrathen,  the  source  of  water  supply  of  Dundee,  was  1,240,  while 

*  Report  of  Engineer  Commission  on  Extension  and  Betterment  of  Cincinnati  Water 
Works,  1896,  p.  15. 


112 


THE   PURIFICATION  OF   WATER. 


the  average  number  of  bacteria  in  the  water  issuing  from  the  lake 
was  30,  showing  a  reduction  in  bacterial  contents  of  the  water  by 
subsidence  of  97.6  per  cent. 

The  same  authority  gives  the  following  results  from  samples  of 
water  from  the  West  Middlesex  Works  for  1892  :  — 

BACTERIA  PER  C.  C.  OF  WATER. 

Thames  water  at  Hampton,  1,437 

Same  water  after  passing  two  storage  reservoirs,  177 

Showing  a  reduction  of  87.7  per  cent  in  the  bacteria  by  a  few  days' 
subsidence. 

In  the  report  of  bacterial  examinations  of  the  river  waters 
supplied  to  London  for  1895,  Dr.  E.  Frankland  gives  the  following 
data  :  — 

AVERAGE  FOR  TWELVE   MONTHS. 


SOURCE  OF  WATER. 

BACTERIA  PER 
C.  C. 

PERCENTAGE 
OF  REDUCTION. 

Thames  at  Hampton, 

•    13,646 

.    .    . 

Chelsea  reservoirs,  13  days'  storage, 

3,177 

76.7 

West  Middlesex  reservoir,  6.3  days'  storage, 

971 

92.9 

Lambeth  reservoir,  6.4  days'  storage, 

3,520 

74.0 

Grand  Junction  reservoir,  short  storage, 

917 

94.0 

River  Lea,  Angel  Road, 

14,075 

.  .  . 

East  London  reservoirs,  15  days'  storage, 

6,280 

55.4 

The  reductions  above  are  obtained  from  natural  subsidence, 
without  the  aid  of  chemicals.  The  author's  experiments  with 
potash  alum  and  slaked  lime,  on  the  suspended  matter  in  the 
Ohio  River  water  have  given  the  following  results :  — 

TAP  WATER  TREATED  WITH   POTASH  ALUM  AND   SLAKED  LIME;   SUSPENDED 
MATTER  ALLOWED  TO  SUBSIDE  DURING  24  HOURS  IN  ICE-CHEST. 


DATE. 

KIND  OF  WATER. 

DAYS  OF 
GROWTH  ON 
GELATIN. 

COLONIES 

PER  C.  C. 

OF  WATER. 

Dec. 
<( 
<( 

11,  1896, 

a        « 

(i        « 

Plain  tap  water, 
Treated  with  2.57  gr.  of  alum  per  gal., 
Treated  with  3.  74  gr.  of  slaked  lime  per  gal.  , 

4 
3 
4 

11,021 
1,674-1,803 
55-      59 

Reduction  by  alum  (without  filtration)  per  cent,         84.22 
Reduction  by  lime  (without  filtration)  per  cent,          99.48 

SEDIMENTATION  OF  POLLUTED    WATERS.  113 

Another  test  of  the  same  water,  treated  with  two  and  a  half 
milligrams  of  potash  alum  to  two  ounces  of  water,  kept  in  ice-chest 
for  forty-eight  hours,  sample  taken  without  disturbing  sediment  in 
bottle,  cultivated  on  gelatin,  gave  the  following  results  :  — 

DATE.  DAYS  OF  GROWTH.       COLONIES  PER  C.  C.  OF  WATER. 

December  13,  1896,  4  1,866-2,315 

Reduction  by  alum  (without  filtration)  per  cent,          81.04 

Hard  water  from  the  Colne  Valley  Water- Works,  according  to 
Professor  Percy  Frankland,  contains  322  bacteria  per  cubio  centi- 
meter, and  after  treatment  for  reduction  of  hardness  by  the  Clark 
process,  with  two  days'  subsidence,  contains  4  bacteria  per  cubic 
centimeter,  indicating  a  reduction  of  the  bacterial  contents,  by  the 
lime  process  and  two  days'  sedimentation,  of  nearly  99  per  cent. 

Another  experiment  by  the  same  authority,  using  the  Clark  pro- 
cess in  combination  with  a  mechanical  separator  in  which  4only  two 
hours  were  allowed  for  deposition  of  the  lime,  gave  the  following 
results  :  — 

Artesian  well  water  (London)  contained  182  bacteria  per  cubic 
centimeter,  while  the  treated  water  issuing  from  the  mechanical 
separator  contained  4  bacteria  per  cubic  centimeter,  showing  a 
reduction  of  nearly  98  per  cent  in  the  bacterial  contents  of  the 
water. 

The  following  experiments  upon  assisted  subsidence  of  the 
bacteria  in  water  are  given  by  Professor  E.  Ray  Lankester,  in  his 
evidence  before  the  Royal  Commission  on  Metropolitan  Water 
Supply :  *  — 

EXPERIMENTS   SHOWING   EFFECT   OF   SUBSIDENCE  OF  MUD  AND   CLAY  ON 
THE   NUMBER   OF   BACTERIA  IN    SUSPENSION    IN    WATER. 

1.  Three  jars,  A,  B,  C,  each  holding  one  liter  of  Oxford  tap 
water,  were  taken  on  June  27,  1892.  To  A  were  added  and  well 
stirred  in,  25  grams  of  sterilized  kaolin  ;  to  B,  similarly  12  grams 
of  sterilized  kaolin  ;  C  was  untouched.  After  15  hours  the  kaolin 
had  completely  subsided,  and  plate  cultures  were  made  from  each 

*  Appendix  C,  p.  456. 


114  THE   PURIFICATION  OF   WATER. 

jar  in  order  to  determine  the  relative  number  of  bacteria  now  in 
suspension  in  the  water. 

From  A,  1,200  colonies  per  c.  c.  were  obtained. 
"      B,  2,790 
"      C,  7,040 

Repetitions  of  the  experiment  yielded  similar  results,  showing 
that  as  much  as  five-sixths  of  the  bacteria  present  were  carried  down 
by;  the  subsiding  kaolin,  when  added  in  proper  quantity. 

N  2.  On  July  7  river  mud  sterilized  by  heat  (80  degrees  C.)  was 
substituted  for  kaolin.  To  one  liter  jar  of  Oxford  tap  water  30 
grams  of  the  river  mud  were  added  and  stirred  in,  while  a  second 
liter  jar  of  the  same  water  was  kept  for  comparison.  The  jars 
stood  undisturbed  for  20  hours.  The  river  mud  having  now  com- 
pletely subsided,  plate  cultures  of  the  water  in  the  two  jars  were 
made.  That  to  which  nothing  had  been  added  showed  55,000 
colonies  per  cubic  centimeter,  while  that  to  which  the  river  mud 
had  been  added  showed  only  15,400  colonies. 

The  experiment  with  sterilized  river  mud  was  repeated  on  July 
26  and  27  with  similar  results  ;  viz.,  a  reduction  of  the  bacteria  by 
subsidence  of  the  mud  to  the  extent  of  nearly  three-fourths. 

(These  experiments  have  importance  not  only  for  the  history  of 
bacteria  in  the  river  normally,  but  especially  for  the  question  of 
the  storage  of  flood  water.  The  subsidence  of  the  mud  suspended 
in  such  flood  water  would  largely  tend  to  purify  the  water  from 
any  excess  of  bacteria.) 

3.  Experiments  on  addition  of  lime  to  river  water.  June  18, 
1892,  two  liter  jars  of  river  water  (Thames,  Oxford)  were  taken  ; 
to  one,  6£  grams  of  slaked  lime  were  added.  After  two  days,  plate 
cultivations  were  made  from  the  water  in  each  jar ;  that  to  which 
no  lime  had  been  added  showed  5,000  colonies  ;  that  to  which  the 
lime  had  been  added  showed  only  280  colonies  per  cubic  centimeter. 

Reduction  by  lime  94.4  per  cent. 

A  similar  experiment  with  tap  water  on  June  20  gave  120 
colonies  without  lime  as  against  15  colonies  where  the  lime  had 
been  added. 

Reduction  by  lime  87.50  per  cent. 


SEDIMENTATION  OF  POLLUTED    WATERS. 


116 


Alum  has  a  still  more  remarkable  effect  than  lime  on  the 
bacteria  in  river  water.  On  the  17th  of  September  two  liters  of 
tap  water  were  taken  for  comparison.  To  one  (liter)  \  gram  of 
alum  was  added.  After  subsidence  (i.e.,  24  hours)  the  untouched 
water  gave  (1)  15,130  colonies,  while  the  water  to  which  the  alum 
had  been  added  gave  none  at  all.  On  the  26th  of  September  a 
similar  experiment  gave  (2)  2,380  colonies  in  the  untouched  water, 
and  8  in  that  to  which  alum  had  been  added. 

Reduction  by  alum  (1)  =  100.00  per  cent. 

Reduction  by  alum  (2)  =    99.66  per  cent. 

The  alum  used  by  Professor  Lankester  amounted  to  14.60 
grains  per  gallon,  which  at  1.6  cents  per  pound  would  make  the 
cost  of  treatment  per  million  U.  S.  gallons  $33.32  for  chemicals 
alone.  No  mention  is  made  of  the  presence  of  undecomposed  alum 
in  the  water,  but  it  cannot  be  doubted  that  with  such  a  proportion 
of  alum  a  considerable  astringency  must  have  been  imparted  to 
the  water. 

EXPERIMENTS    ON    THE    PRECIPITATION    OF    THE    SUSPENDED    MATTER 
IN   OHIO   RIVER   WATER. 

The  data  detailed  in  the  table  below  were  collected  by  Mr. 
Edward  Flad,  C.E.,  in  connection  with  certain  experiments  on 
sedimentation  for  the  city  of  Cincinnati,  1889,  and  indicate  that 
sedimentation  for  an  interval  as  short  as  40  hours  will  reduce  the 
suspended  matter  by  weight  nearly  80  per  cent. 

EXPERIMENTS   ON  THE    PRECIPITATION   OF  THE   SUSPENDED   MATTER   IN 
OHIO   RIVER   WATER   AT  CINCINNATI,   OHIO. 


No.  OF 
SAMPLE. 

DATE,  1889. 

HOURS  OF 
SETTLING. 

SILT  HELD  IN  SUSPENSION 
PARTS  BY  WEIGHT  PER  1,000. 

PERCENTAGE 
OF  SILT 
REMOVED  BY 
SETTLING. 

Before  Settling. 

After  Settling. 

4 

Jan.     7 

42.2 

0.3635 

0.1225 

66.3 

2 

9 

47.0 

0.3610 

0.1135 

68.5 

5 

11 

46.3 

0.2350 

0.1435 

38.9 

7 

13 

48.0 

0.1005 

0.0490 

51.2 

8 

15 

47.1 

0.0920 

0.0330 

64.1 

14 

17 

47.3 

0.3900 

0.1305 

66.5 

13 

19 

46.5 

0.1590 

.  .  . 

.  .  . 

17 

21 

48.2 

0.2011 

0.0932 

53.6 

26 

23 

41.5 

0.0865 

0.0246 

71.5 

116 


THE  PURIFICATION  OF   WATER. 


EXPERIMENTS  ON   PRECIPITATION.-  Continued. 


No.  OF 
SAMPLE 

DATE,  1889. 

HOURS  OF 
SETTLING. 

SILT  HELD  IN  SUSPENSION 
PARTS  BY  WEIGHT  PER  1,000. 

PERCENTAGE 
OF  SILT 
REMOVED  BY 
SETTLING. 

Before  Settling. 

After  Settling. 

24 

Jan.  25 

30.4 

0.0405 

0.0540 

19 

26 

40.4 

0.0955 

0.0220 

75.9 

29 

29 

5.3 

0.1640 

0.0720 

56.1 

30 

29 

40.3 

0.2235 

0.0580 

74.0 

31 

31 

30.3 

0.2225 

0.1098 

50.6 

33 

Feb.     1 

41.2 

0.3095 

0.0720 

76.8 

34 

3 

31.5 

0.2760 

0.0910 

67.0 

38 

4 

42.0 

0.1900 

0.0445 

76.5 

40 

6 

28.2 

0.1615 

0.0615 

61.9 

43 

7 

40.3 

0.1548 

0.0560 

63.8 

61 

9 

30.3 

0.0555 

0.0325 

39.6 

60 

10 

40.4 

0.0450 

0.0220 

51.1 

44 

12* 

30.6 

0.0415 

0.0360 

13.2 

62 

13 

41.1 

0.0462 

0.0188 

69.3 

67 

15 

30.2 

0.0665 

0.0125 

81.2 

69 

16  > 

39.4 

0.2635 

0.0330 

85.8 

77 

18 

31.0 

0.5425 

0.1287 

76.3 

74 

19 

40.5 

0.5900 

0.1085 

81.6 

75 

21 

31.5 

0.5623 

0.1628 

71.1 

78 

22 

41.2 

0.3780 

0.0945 

75.0 

80 

24 

29.6 

0.3455 

0.0855 

75.3 

83 

25 

40.3 

0.3811 

0.0930 

75.6 

84 

27 

47.1 

0.2940 

0.0765 

74.0 

A  review  of  the  data  in  the  table  indicates  that  the  greatest 
percentage  of  reduction  of  the  silt  accompanies  the  greatest  tur- 
bidity of  the  river  water. 

Experiments  by  the  author  upon  the  rate  of  reduction  of  the 
suspended  matter  in  the  Ohio  River  water  have  given  the  follow- 
ing results  :  — 

SEDIMENTATION  OF   SUSPENDED   MATTER   IN  OHIO   RIVER  WATER, 
DECEMBER,  1896. 

PARTS  PER  100,000. 

Original  amount  of  matter  in  suspension,  54.00 

Matter  in  suspension  at  end  of  two  days,  15.00 

Matter  in  suspension  at  end  of  four  days,  13.50 

.     Matter  in  suspension  at  end  of  six  days,  12.00 

Showing  a  reduction  of  72  per  cent  of  the  suspended  matter  in 

two  days,  75  per  cent  in  four  days,  and  77.8  per  cent  in  six  days. 

The  rate  of  subsidence  will  depend  upon  the  specific  gravity  of 


SEDIMENTATION  OF  POLLUTED    WATERS. 


117 


the  matter  in  suspension,  and  the  quiescence  of  the  water  under- 
going sedimentation.  When  the  specific  gravity  of  the  suspended 
matter  is  considerably  in  excess  of  one,  and  the  water  altogether 
at  a  state  of  rest,  the  precipitation  will  be  rapid.  Conversely,  with 
a  specific  gravity  of  the  suspended  matter  not  much  above  that  of 
water,  and  the  water  in  a  state  of  agitation,  the  sedimentation  will 
be  slow,  and  under  unfavorable  conditions  there  may  be  no  precipi- 
tation by  subsidence  at  all. 

The  reduction  of  organic  matter  in  water  by  subsidence  is  due 
partly  to  precipitation  of  matters  heavier  than  water,  and  partly  to 
destruction  of  organic  matter  in  suspension  by  bacterial  action  ; 
while  the  reduction  of  the  bacterial  contents  of  water  by  sedimen- 
tation is  accomplished  partly  by  precipitation  of  the  bacteria  in 
contact  with  the  suspended  matter,  and  partly  by  the  natural 
decay  of  the  less  hardy  species  of  the  water  bacteria.  In  the 
biologic  action  which  occurs  in  large  bodies  of  water,  the  weaker 
species  of  the  bacteria,  as  organic  matter,  are  absorbed  by  or  be- 
come food  for  the  stronger  species  ;  and  this  process  of  the  destruc- 
tion of  the  weaker  by  the  stronger  forms  goes  on  until  all  food 
supply  is  exhausted,  whereupon  the  strongest  species 'perish,  and 
in  a  manner  still  to  be  explained  are  converted  into  the  harmless 
nitrogenous  compounds,  and  as  such  are  precipitated  along  with 
the  inorganic  matters  in  suspension  in  all  surface  waters. 


REDUCTION    OF   HARDNESS   AND   BACTERIAL    CONTENTS 
BY   ADDITION    OF     LIME. 

Experiments  conducted  by  Mr.   Dibdin,*  on  the  water  of  the 
New  River  Company  furnished  the  following  results  :  — 


DATE. 

BEFORE  TREATMENT. 

AFTER  TREATMENT. 

PERCENTAGE  OF 
REDUCTION. 

Hardness. 

Bacteria. 

Hardness. 

Bacteria. 

Hardness. 

Bacteria. 

Dec.  16,  1895. 

17.4 

96 

5.4 

12 

68.4 

87.5 

Dec.  18,      " 

17.4 

110 

5.0 

6 

71.3 

94.5 

Dec.  20,      " 

17.4 

60 

8.5 

16 

51.2 

73.4 

1896. 


Analytical  Investigations  of  London  Water  Supply,  London  County  Council,  January, 


118  THE  PURIFICATION  OF   WATER. 

The  lime  treatment  reduced  the  red  color  in  the  water,  by 
Lovibond's  tintometer,  100  per  cent,  and  the  yellow  color  35  per 
cent.  No  change  was  noticed  in  the  "free  ammonia"  after  and 
before  treatment,  while  the  albuminoid  ammonia  was  reduced  23 
per  cent.  The  chlorine  was  unaffected  by  the  treatment,  while  the 
oxygen  absorbed  on  a  four-hour  test  before  and  after  treatment  was 
reduced  25  per  cent. 

The  total  solids  were  reduced  from  an  average  of  24.3  parts 
per  100,000  parts  of  water  before  treatment  to  11.8  parts  after 
treatment.  In  all  the  tests  the  water  was  dosed  with  9.4  per  cent 
of  a  saturated  lime-water.  Of  these  tests  Mr.  Dibdin  says,  "  It 
would  therefore  seem  that  by  the  adoption  of  the  system  of  soft- 
ening, the  present  supply,  in  respect  to  its  chemical  quality  and 
bacteria,  would  be  improved  to  a  degree  comparable  with  that  of 
the  Welsh  sources."  * 

Such  experience  as  has  been  had  along  the  line  of  reduction  of 
hardness  in  water  for  city  supply  has  revealed  the  interesting  fact, 
that  the  addition  of  lime  to  a  hard  (polluted)  water  is  effective  in 
the  purification  of  the  water,  as  well  as  in  the  reduction  of  the 
hardness,  as  indicated  by  the  experiments  previously  noted. 

Elaborate  appliances  for  the  lime  treatment  of  water  are  now 
being  built  by  several  companies  abroad,  and  the  author  is  in- 
formed that  the  Jewell  Filter  Company  of  Chicago  has  built  some 
apparatus  for  this  purpose  for  cities  in  this  country. 

With  reference  to  the  cost  of  water  softening  on  .a  very  large 
scale,  the  following  information  is  abstracted  from  Reports  by  Mr. 
W.  J.  Dibdin,  chemist,  and  Sir  Alex.  R.  Binnie,  engineer,  to  the 
London  County  Council,  on  the  London  Water  Supply  for  1895. 

Considering,  according  to  Mr.  Dibdin,  the  cost  of  lime  alone 
for  a  daily  treatment  of  200,000,000  imperial  gallons,  this  will 
amount  to  £35,000  or  $175,000  per  year.  Considering  the  cost 


*  It  is  not  within  the  province  of  this  work  to  discuss  projects  of  water  supply  ;  but  it  may  be 
of  interest  to  mention  that  the  Welsh  sources  with  which  Mr.  Dibdin  compares  the  lime-treated 
London  water  are  ably  and  elaborately  presented  in  a  Report  by  Sir  Alexander  R.  Binnie  to  the 
London  County  Council,  entitled,  Available  Sources  of  Water  Supply  for  London,  June,  1894. 

The  development  of  these  sources  in  Wales  will  provide  a  daily  supply  of  415,000,000  im- 
perial gallons,  at  an  estimated  cost  of  nearly  $200,000,000,  the  water  to  be  conducted  to  the 
metropolis  through  two  aqueducts  150  and  176  miles  long. 


SEDIMENTATION  OF  POLLUTED    WATERS.  119 

of  lime  and  all  labor,  Mr.  Binnie  puts  this  at*  .£300  to  £310  per 
million  imperial  gallons  treated  daily  per  year,  while  the  cost  of  ap- 
paratus and  buildings  for  lime  treatment,  he  estimates  at  .£3,500  to 
£4,500  or  $20,000  per  million  imperial  gallons  treated  daily.  For 
the  present  daily  consumption  of  water  by  London  (200,000,000 
imperial  gallons),  Mr.  Binnie  puts  the  annual  cost  at  £60,000  or 
$300,000. 

Reducing  these  figures  to  our  measures  and  values,  the  annual 
cost  for  1,000,000  U.  S.  gallons  treated  per  day,  for  a  reduction 
from  a  hardness  of  17  degrees  by  Clark's  scale  to  about  5  degrees 
for  lime  alone,  according  to  Mr.  Dibdin,  becomes  1708.00  ;  and 
the  whole  cost  of  lime  and  labor,  according  to  Mr.  Binnie,  will  be 
$1,270.32,  or  about  ^  cent  per  1,000  gallons  of  water  treated. 
These  figures  are  based  upon  the  treatment  of  240,000,000  U.  S. 
gallons  per  day,  and  this  cost  would  naturally  not  be  applicable  to 
small  quantities  of  water  per  diem. 


120  THE   PURIFICATION  OF   WATER. 


CHAPTER    IX. 

STERILIZATION    OF   DRINKING-WATER.* 

SEVERAL  years  ago,  in  discussing  the  hygiene  of  public  water 
supply,  the  author  took  the  ground,  that,  as  the  proportion  of  water 
used  for  drinking-purposes  was  one-half  per  cent  or  less  of  the 
whole  quantity  consumed  by  the  takers  from  a  public  source,  the 
better  plan  was  not  to  attempt  to  secure  the  whole  supply  of  po- 
table quality,  but  to  render  any  water  available  fit  for  drinking- 
purposes  by  domestic  filtration.  Later  experience  satisfies  him 
that  this  plan  will  not  answer  for  several  reasons  :  — 

1.  All  consumers  of  a  public  water  supply  cannot,  or  will  not, 

use  domestic  filters. 

2.  There  is  no  domestic  filter  which  is  absolutely  proof  against 

the  dangers  of  polluted  water. 

3.  Even  if  a  satisfactory  filter  was  obtainable,  it  is  doubtful  if 

the  average  householder  would  give  this  the  attention 
it  requires  to  keep  it  at  all  times  in  condition  to  act  as 
a  safeguard. 

In  view  of  which  the  conclusion  has  been  reached,  that  if  the 
consumer  is  to  have  a  safe  drinking-water,  it  must  come  to  him  in 
this  condition  through  the  public  water  mains.  In  other  words, 
the  matter  of  purity  must  be  looked  after  by  the  municipal  corpo- 
ration or  the  water  company.  The  prevalence  of  typhoid  fever  in 
any  city  or  town  having  a  public  water  supply  is  evidence  that 
the  water  now  generally  furnished  to  consumers  is  unpotable,  and 
that  municipal  corporations  and  water  companies  are  delivering  to 
their  consumers  water  containing  the  specific  organism  of  typhoid 
fever. 

*  A  portion  of  this  chapter  is  abstracted  from  a  paper  by  the  author,  read  at  the  Eighth 
International  Congfess  of  Hygiene  and  Demography,  Buda-Pest,  Austria,  September,  1894. 


STERILIZATION  OF  DRINKING-WATER. 

It  is  common  for  physicians  in  case  of  doubt  of  the  purity  of  a 
water  supply,  to  recommend  that  water  for  drinking-purposes  be 
boiled  ;  but  the  boiling  of  water  renders  it  insipid  and  unpalatable, 
and  it  is  claimed  by  some  of  the  manufacturers  of  filters  that  water 
deprived  of  certain  of  its  natural  gases  and  solids  in  solution  (as  it 
will  be  by  boiling)  is  not  as  wholesome  as  natural  waters.  The 
author  has  been  unable  to  obtain  any  reliable  information  of  the 
influence  on  the  human  system  of  the  salts  and  gases  in  solution 
in  natural  waters,  and  is  uncertain  whether  the  continuous  use  of 
boiled  water  as  a  beverage  will  be  deleterious.  Considering  that 
filtered  and  boiled  water  will  be  limpid  and  sterile  and  deprived  of 
all  toxic  properties,  and  assuming  that  such  water  will  not  be  in- 
jurious to  the  system,  may  not  the  problem  of  an  absolutely  safe 
drinking-water  finally  be  solved  by  combined  filtration  and  distilla- 
tion ?  If  carried  out  to  its  legitimate  conclusion  this  would  mean 
the  treatment  of  a  sufficient  quantity  of  water  by  the  municipal 
corporation  for  drinking  and  culinary  purposes,  and  the  delivery  of 
this  to  consumers  through  an  independent  system  of  comparatively 
small  mains.  But  the  expensive  apparatus  for  distillation ;  the  cost 
of  duplicating  the  street  mains,  even  with  pipes  of  small  diameter ; 
and  especially  the  large  annual  expense  of  operation,  —  might  at 
first  sight  seem  to  prohibit  any  attempt  by  this  process  to  purify 
water  on  a  large  scale. 

For  the  purpose  of  estimating  the  probable  cost  of  this  method 
of  water  purification  for  city  use,  let  us  take  an  American  city 
with  a  population  of  400,000,  and  allow  a  daily  consumption  of 
water  for  all  purposes  of  40,000,000  U.  S.  gallons,  or  100  gallons 
per  head  of  population  ;  of  which  quantity  it  will  be  assumed 
that  2^  per  cent,  or  1,000,000  gallons  per  day,  is  used  exclu- 
sively for  drinking  and  cooking  purposes,  including  water  for  the 
washing  of  culinary  vessels  and  apparatus.  To  sterilize  by  heat 
1,000,000  U.  S.  gallons  of  water  per  day  of  24  hours  will  require 
an  hourly  distillation  of  347,100  pounds  ;  and  assuming  the  average 
temperature  of  the  filtered  water  (or  feed  water)  to  the  boilers 
to  be  60°  Fahr.,  and  the  pressure  of  distillation  to  be  six  pounds 
above  the  atmosphere,  then  the  total  heat  to  be  added  to  each 
pound  of  water  will  be  1,124  B.  T.  u. 


122  THE   PURIFICATION  OF   WAITER. 

If  the  steam  in  going  from  the  boilers  to  the  surface  con- 
densers be  made  to  pass  through  suitable  closed  heaters,  through 
which  also  the  cold  water  to  the  boilers  is  being  pumped,  then  a 
part  of  the  heat  of  the  steam  will  be  given  up  to  the  feed  water, 
and  a  smaller  amount  of  heat  will  be  required  from  the  coal  or 
other  fuel  to  sterilize  a  given  amount  of  water,  and  a  smaller  ca- 
pacity of  boilers  and  surface  condensers  will  be  required.  Since 
the  cold  water  from  the  niters  will  be  pumped  under  full  boiler 
pressure  through  these  closed  heaters,  it  will  be  possible  (if  such 
heaters  are  of  sufficient  capacity)  to  supply  to  the  water  not  only 
the  sensible  heat,  but  a  part  of  the  latent  heat  from  the  heat  in 
the  steam  before  it  is  finally  condensed  in  the  surface  condensers ; 
or  of  the  heat  in  the  sterilized  water  a  large  percentage  can  be 
recovered  and  utilized  in  heating  the  filtered  water  to  the  boilers, 
with  a  corresponding  saving  of  fuel. 

The  cost  of  fuel  being  the  bete  notrin  the  problem  of  steriliz- 
ing by  heat  the  drinking-water  for  a  city,  it  is  desirable  that  the 
facts  in  connection  with  the  expenditure  of  fuel  be  carefully  and 
fully  considered.  The  rate  at  which  the  feed  water  is  pumped  to 
the  boilers  being  the  same  as  the  rate  of  flow  of  steam  through 
the  heaters  to  the  condensers,  it  follows,  that,  if  the  heaters  were 
large  enough  and  sufficient  time  allowed  for  the  passage  of  the 
steam  through  them,  and  there  were  no  losses  of  heat  by  radia- 
tion, etc.,  one-half  of  the  heat  of  the  steam  would  be  transferred 
to  the  water  on  its  way  to  the  boilers ;  or  of  the  1,124  heat  units 
added  per  pound  of  water  in  the  boilers,  562  units  would  be  car- 
ried back  in  the  feed  water.  But  the  recovery  of  50  per  cent  of 
the  heat  assumes  an  efficiency  beyond  the  reach  of  ordinary  heat- 
ing apparatus  ;  and  some  allowance  must  be  made  for  the  losses 
by  conduction  and  radiation,  and  by  contact  of  air,  which  can  safely 
be  put  at  10  per  cent ;  and  considering  the  very  slow  rate  of 
transfer  of  heat  when  the  temperature  of  the  steam  (partially  con- 
densed) and  that  of  the  feed  water  approximate  each  other,  it 
will  be  safe  to  allow  another  10  per  cent  loss  upon  account 
of  time  ;  from  which,  as  a  practical  proposition,  it  is  estimated 
that  of  the  heat  carried  off  from  the  boilers  by  the  steam,  30 
per  cent  may  be  recovered  in  the  feed-water  heaters,  leaving 


STERILIZATION  OF  DRINKING-WATER.  123 

70  per  cent  to  be  taken  up  by  the  cooling  water  in  the  surface 
condensers. 

It  will  therefore  be  necessary  to  supply  to  each  pound  of  water 
pumped  into  the  boilers  1,124  x  .7  =  787  heat  units ;  and  with 
coal  and  boilers  showing  an  efficiency  of  11,250  heat  units  per 
pound  of  fuel,  each  pound  of  coal  will  distill  14.3  pounds  of  water 
at  6  pounds  pressure  above  the  atmosphere ;  and  for  the  distilla- 
tion or  sterilization  of  347,100  pounds  per  hour  (1,000,000  U.  S. 
gallons  per  day),  there  will  be  required  291  tons  (2,000  pounds) 
of  coal,  or  an  annual  consumption  of  106,215  tons. 

The  boiler  capacity  to  distill  this  amount  of  water  daily  has 
been  estimated  as  follows  :  An  ordinary  return  tubular  boiler  sup- 
plied with  water  at  60°  Fahr.,  and  working  at  six  pounds  pressure 
above  atmosphere,  will  easily  evaporate  3.5  pounds  per  hour  per 
square  foot  of  heating  surface ;  and  if  the  heat  required  per  pound 
of  water  be  787  instead  of  1,124  thermal  units,  then  each  superfi- 
cial foot  of  heating  surface  can  be  expected  to  evaporate  5  pounds 
of  water  per  hour ;  and  for  the  evaporation  of  347,100  pounds  per 
hour,  there  will  be  required  a-u^sm  =  69,420  square  feet  of  heat- 
ing surface.  Allowing  2,000  square  feet  to  each  boiler,  there  will 
be  required  35  boilers,  each  6  feet  6  inches  diameter  by  18  feet 
long,  with  the  proper  complement  of  tubes.  The  feed-water  heat- 
ers to  heat  the  filtered  water  and  partially  condense  the  steam  from 
the  boilers  have  been  estimated  in  the  following  manner  :  — 

Each  square  foot  of  surface,  taking  the  tube  in  the  heater  as 
-fV  inch  or  less  in  thickness,  will  readily  transfer  4,000  thermal 
units  per  hour,  equivalent  to  the  heating  through  337°  Fahr.  of 
12  pounds  of  water  ;  and  to  heat  3-±7£o_o  pounds  will  require 
29,000  square  feet  of  heating  (or  cooling)  surface  in  the  heaters  ; 
or  with  an  allowance  of  1,000  square  feet  of  surface  to  each 
heater,  there  will  be  required  29  heaters  to  deal  with  1,000,000 
gallons  of  water  per  day. 

Surface  condensers  constructed  with  thin  brass  tubes  can  be 
estimated  to  condense  15  pounds  of  steam  per  square  foot  of  cool- 
ing surface  per  hour ;  and  if  these  also  are  of  1,000  square  feet 
each,  there  will  be  required,  to  deal  with  1,000,000  gallons  of  water 
in  24  hours,  23  such  condensers. 


124  THE  PURIFICATION  OF   WATER. 

The  apparatus,  therefore,  which  we  have  outlined  for  the  sterili- 
zation by  heat  of  1,000,000  U.  S.  gallons  of  water  per  day,  consists 
in  detail  of  a  duplicate  filter  plant,  each  half  of  1,000,000  gallons 
daily  capacity ;  pumping  machinery  in  duplicate  of  1,000,000 
gallons  daily  capacity  to  take  the  filtered  water  and  supply  it  to 
the  boilers  ;  steam-boilers  to  evaporate  the  water  under  low  pres- 
sure ;  closed  feed-water  heaters  to  cool  the  steam  and  heat  the 
feed  water ;  surface  condensers  to  condense  the  steam  ;  and  pump- 
ing machinery  to  take  the  condensed  steam  and  sterilized  water, 
and  pump  it  into  the  mains  for  distribution  to  the  consumers. 
The  filters,  heaters,  and  steam-boilers  will  require  buildings  for 
their  protection  from  the  weather,  while  the  condensers  may  be 
exposed  to  the  weather  without  detriment  to  their  operation  or 
durability.  In  addition  to  the  apparatus  mentioned,  for  a  city 
of  the  population  we  have  assumed,  there  will  be  required  about 
350  miles  of  mains  of  small  diameter,  to  distribute  the  sterilized 
water  to  the  various  premises  to  be  supplied. 

We  are  now  ready  to  estimate  the  cost  of  constructing  and 
operating  such  a  plant  for  water  purification  :  — 

COST  OF  CONSTRUCTION. 

Two   filter   plants,    each   of    1,000,000   gallons   daily 

capacity,  $15,000.00 

Filter-house,  4,000.00 

Thirty-five  steam-boilers,  complete,  63,000.00 

Twenty-nine  feed-water  heaters,  complete,  29,000.00 

Twenty-three  surface  condensers,  complete,  34,500.00 

Boiler-house,  30,000.00 

Two  sets  of  pumping  machinery,  each  set  of  1,000,000 
gallons  daily  capacity,  to  supply  the  filtered  water 
to  the  boilers,  9,000.00 

Two  sets  of  pumping  machinery,  each  set  of  1,000,000 
gallons  daily  capacity,  to  pump  the  sterilized  water 
into  the  mains,  12,000.00 

Pumping-station,  12,000.00 

Add  for  pipes,  valves,  etc.,  at  sterilizing-station,  20,000.00 

350  miles  of  mains  at  an  average  cost  of  $4,500  per 

mile,  1,575,000.00 

Total,  $1,803,500.00 
Cost  per  capita  of  population,  $4.50. 


STERILIZATION  OF  DRINKING-WATER-  125 

FIXED  ANNUAL  CHARGES. 

Interest  on  cost  of  construction  at  5^>,  $90,175.00 
Annual  payment  to  sinking-fund  to  redeem  construc- 
tion bonds  invested  at  4^  for  40  years,  18,972.82 
Total,  $109,147.82 

OPERATING  EXPENSES. 

106,215  tons  of  coal  at  $2,  $212,430.00 

Forty-five  men  at  $2  per  day,  and  five  men  at  $3  per  day,  38,325.00 

Total  annual  cost,  $359,902.82 

Annual  cost  of  operating,  and  fixed  charges  per  capita,  $0.90 

Or  for  filtration  and  sterilization  of  the  drinking-water  for  a 
city  of  400,000  population,  the  cost  per  capita  per  annum  cannot 
be  in  excess  of  $1.  Are  we  prepared  to  pay  this  for  absolute 
immunity  from  typhoid  fever  and  other  water-borne  diseases  ? 

The  Yaryan  Company  of  New  York  has  kindly  furnished  the 
author  an  estimate  of  cost  and  operation  for  a  water-sterilizing 
plant  upon  its  system,  which  will  be  more  economical  of  fuel  and 
labor  than  the  simple  apparatus  described.  Adopting  in  our 
estimate  the  figures  supplied  by  this  company,  the  costs  are  as 
follows  :  - 

COST  OF  CONSTRUCTION. 

Filters  and  filter-house,  $     19,000.00 

Yaryan  quadruple  effect  sterilizer,  225,000.00 

Boiler-house,  30,000.00 

Pumping  machinery  and  station,  33,000.00 

Distributing  mains,  1,575,000.00 

Total,  $1,882,000.00 

FIXED  ANNUAL  CHARGES. 

Interest  and  sinking-fund,  $113,898.64 

OPERATING  EXPENSES. 

100  tons  of  coal  per  day,  at  $2,  for  one  year,  $73,000.00 

15  men  at  $2  per  day,  and  4  men  at  $3  per  day,  15,330.00 

Total  annual  cost,  $202,228.64 

Annual  cost  of  operating  and  fixed  charges  per  capita,  $0.50 
Or  $.0554  per  1,000  gallons,  sterilized  and  delivered. 

This  scheme  for  water  purification  involves,  as  shown,  a  sepa- 
rate system  of  small  mains  to  convey  the  sterilized  and  filtered 
water  from  the  works  to  the  consumers,  and  requires  a  separate 


126  THE  PURIFICATION  OF   WATER. 

service  pipe  from  these  mains  to  bring  the  water  into  each  prem- 
ises, after  which,  as  a  measure  of  hygiene,  the  use  of  such  water 
for  drinking  and  cooking  purposes  should,  if  found  necessary, 
be  made  compulsory. 

It  will  be  noticed  that  no  allowance  has  been  made  in  the  cost 
of  operating  for  the  cooling  water  to  the  surface  condensers,  because 
the  97-98  per  cent  (or  as  much  of  it  as  may  be  required)  of  un- 
sterilized  water  supplied  to  the  city  may  be  made  to  pass  through 
the  condensers  as  cooling  water  without  extra  cost. 

In  regard  to  the  figures  heretofore  given,  it  is  not  the  purpose 
to  state  with  precision  all  the  details  of  cost  of  this  method  of 
water  purification,  but  rather  to  lay  down  a  principle,  and  let  it  be 
worked  out  for  each  particular  case.  Doubtless  in  some  cities  the 
cost  of  construction  and  operation  will  be  less  than  has  been  shown, 
while  in  others,  for  local  reasons,  it  may  be  greater.  But  it  is  rea- 
sonable to  claim  that  sterilized  and  filtered  water  can  be  obtained 
in  our  larger  cities  within  the  cost  given,  or  at  about  one-tenth 
cent  per  gallon ;  and  the  purpose  of  the  approximate  figures  stated 
on  the  previous  page  is  to  show  that  the  cost  per  unit  of  volume, 
or  per  capita  of  population,  for  absolutely  sterile  water,  is  not  so 
great  as  to  prohibit  its  use  if  demanded  by  the  people. 

Water  such  as  this  process  of  purification  will  furnish  can 
neither  be  the  habitat  nor  carrier  of  any  kind  of  bacteria  (nor  of 
the  toxalbumins  which  these  may  develop)  ;  and  if  any  organisms 
came  into  it  adventitiously,  they  would  perish  for  lack  of  food. 

One  great  difficulty  in  the  way  of  introducing  a  process  for 
the  sterilization  of  drinking-water  on  a  large  scale  in  the  United 
States,  lies  in  the  well-known  fact  that  the  construction  of  public 
works  of  any  magnitude  in  most  cities  is  seized  upon  as  a  political 
advantage  by  the  dominant  party ;  and  the  average  tax-payer,  upon 
whom  the  burden  of  cost  falls,  usually  views  with  alarm  any  prop- 
osition to  inaugurate  an  improvement  requiring  a  large  outlay  of 
money,  in  spite  of  the  fact,  perhaps,  that  his  health  or  that  of  his 
family,  and  possibly  their  lives,  may  depend  upon  the  construction 
of  such  works.  In  cities,  however,  like  Berlin,  Vienna,  and  St. 
Petersburg,  which  are  under  imperial  control,  no  difficulty  should 
be  experienced  in  establishing  a  process  for  the  sterilization  and 


STERILIZATION  OF  DRINKING-WATER. 


127 


Side  Elevation. 
Fig.  4-. 


Section  Showing  Circulation. 
Fig.  5. 

Figs.  3,  4,  and  5.     Yaryan  Apparatus  for  Sterilizing  Water.    Quadruple  Effect 


128  THE   PURIFICATION  OF   WATER. 

special  distribution  of  the  small  percentage  of  water  used  for 
drinking  and  culinary  purposes  whenever  the  health  boards  are 
ready  to  recommend  it.  When  this  shall  be  done  by  these  or  any 
other  cities,  and  the  sterilized  water  is  used  by  all  the  citizens, 
then  such  cities  will  be  absolutely  free  from  typhoid  fever  and 
other  water-borne  diseases  so  far  as  these  may  be  chargeable  to 
the  local  water  supply.  But  no  amount  of  care  upon  the  part  of 
any  city  to  defend  its  water  supply  from  pollution,  or  render  it  safe 
to  health  as  a  drinking-water  after  pollution,  can  prevent  the  im- 
portation of  typhoid  fever  from  some  other  locality,  where  the 
hygienic  regulations  for  the  drinking-water  are  less  rigid,  and 
where  the  water  contains  the  typhoid  germ.  From  which  we 
reason  that  a  system  or  process  for  the  purification  of  drinking- 
water,  to  be  wholly  effective,  must  be  universal  in  its  application  ; 
but  no  sanitary  improvement,  however  essential  it  may  be  to 
health,  has  been,  or  ever  will  be,  applied  everywhere  at  one  and 
the  same  time.  It  must  have  its  origin  in  some  city,  the  effica- 
cious results  must  be  shown  and  published  ;  whereupon  other 
cities,  towns,  and  localities  will  speedily  adopt  it,  and  in  due  time 
the  benefits  of  such  improvement  will  be  enjoyed  by  all  the  civil- 
ized people  of  the  earth. 

During  the  World's  Fair  at  Chicago,  1893,  all  the  employees, 
numbering  nearly  15,000,  used  sterilized  drinking-water,  with  the 
result  that  so  long  as  this  water  only  was  used,  no  diarrheal 
troubles  were  reported  among  the  men.  Upon  the  few  occasions 
when  for  short  intervals  of  time  the  sterilized  drinking-water  was 
discontinued,  intestinal  disorders  arose ;  and  where  typhoid  fever 
occurred,  it  was  traced  to  a  disregard  of  the  rules  of  the  Exposi- 
tion with  reference  to  drinking-water.* 

The  sterilization  of  the  water  was  effected  by  passing  it 
through  an  ordinary  feed-water  heater,  where  it  was  raised  to  212° 
Fahr.,  and  kept  at  this  temperature  for  a  short  time.  Analysis  of 
the  water  revealed  no  bacterial  life. 

According  to  Surgeon-General  Tryon  of  the  United  States 
Navy,f  "  It  may  be  stated  that  the  medical  officers  of  the  navy 

*  Proceedings  Fourteenth  Annual  Meeting  A.  W.  W.  Association,  pp.  22-24. 

t   Water  Supply,  Chemical  and  Sanitary,  Wm.  P.  Mason,  New  York,  1896,  p.  156. 


STERILIZATION  OF  DRINKING-WATER.  129 

recognize  the  great  value  of  distilled  water  in  the  improvement  in 
health  that  has  followed  its  introduction,  particularly  in  certain 
foreign  stations." 

No  one  will  venture  to  deny  that  water  properly  sterilized  by 
heat  in  an  ordinary  steam-boiler  will  be  absolutely  safe  for  drink- 
ing-purposes.  All  the  bacteria  or  organic  matter  (in  solution) 
originally  in  such  water  will  be  wholly  destroyed  or  precipitated 
by  evaporation  under  atmospheric  pressure  in  a  closed  generator ; 
and  if  we  accept  the  proof  that  water  is  the  carrier  or  original 
cause  of  typhoid  fever,  then  we  are  compelled  to  admit  that  water 
properly  sterilized  cannot  foster  or  carry  the  bacillus.  With  such 
water  universally  used  for  drinking  and  cooking  purposes,  the 
typhoid  bacillus  would  perish,  and  typhoid  fever  cease  to -exist. 

With  few  exceptions,  it  is  vain  to  look  for  water  wholly  safe 
for  drinking-purposes  at  its  source.  Few  cities  enjoy  such  water 
to-day,  otherwise  among  their  inhabitants  who  use  the  water  ex- 
clusively typhoid  fever  would  be  unknown ;  and  doubtless  in  any 
city  where  the  water  is  of  such  quality  that  analysts  have  pro- 
nounced it  safe  for  drinking-purposes,  it  is  being  drunk  to  the 
exclusion  of  any  other  available  water. 

The  principal  objections  which  have  been  offered  to  a  double 
water  supply,  whether  the  water  of  better  quality  is  improved  by 
sterilization  or  filtration,  or  is  naturally  of  high  quality,  are  :  — 

1.  The  better  water  will  not  always  be  used  for  drinking  and 

dietetic  purposes.  Some  people  will  forget  the  danger 
of  drinking  the  unpurified  water,  and  resort  to  that 
which  is  most  convenient,  thereby  defeating  the  very 
purpose  of  a  double  supply. 

2.  It  is  urged  that  many  of  the  poorer  people  cannot  afford 

to  introduce  two  kinds  of  public  water  into  their  houses. 

3.  In  many  instances  the  better  water  will  be  used  for  other 

than  dietetic  purposes. 

The  first  of  these  objections  can  be  overcome  by  proper  edu- 
cation and  example.  The  instinct  of  self-preservation  must  be 
wrought  upon,  and  the  natural  tendency  to  take  the  better  of  two 
things  equally  attainable  may  be  expected  to  encourage  the  use  of 


130  THE   PURIFICATION  OF   WATER. 

the  better  water  for  drinking  and  culinary  purposes.  The  second 
objection  can  be  overcome  by  gentle  .compulsion,  in  the  same 
manner  that  other  sanitary  improvements  are  carried  out  by  mu- 
nicipal corporations  at  the  cost  of  the  property  benefited.  The 
third  objection  can  readily  be  overcome  by  metering  the  purer 
water  supply,  and  in  cases  where  such  water  is  freely  used  about 
the  premises  the  cost  thereof  will  be  paid  by  the  consumer. 

It  is  probable  that  now  a  system  of  double  water  supply  is 
rather  too  refined  for  most  municipal  corporations,  but  it  is  possible 
that  such  may  be  demanded  by  future  generations.  Many  physi- 
cians and  hygienists  at  the  present  time  favor  the  dual  system, 
through  one  branch  of  which  water  of  the  highest  quality  is  to  be 
delivered  for  drinking  and  culinary  purposes,  while  through  the 
other,  water  for  the  coarser  uses  is  supplied  to  the  consumers. 

NOTE. —  Referring  to  the  Yaryan  Apparatus  for  the  sterilization  of  drinking-water  (p.  125), 
quite  extensive  plants  on  this  system  have  been  in  operation  for  several  years  at  Perim  and 
Kosseir,  on  the  Red  Sea,  and  at  Troon,  Scotland ;  converting  from  6,000  to  12,000  gallons  of 
sea-water  into  fresh  water  per  day  of  24  hours,  with  an  expenditure  of  about  \  pound  of  coal 
per  gallon  of  water  distilled,  including  the  water  for  the  boilers,  and  the  fuel  for  operating  the 
necessary  pumping-machinery. 


FILTRATION  OF   WATER  SUPPLIES.  131 


CHAPTER    X. 

FILTRATION   OP   WATER   SUPPLIES. 

THE  purpose  of  this  chapter  is  the  discussion  of  devices  and 
plans  for  the  purification  of  large  volufnes  of  water  for  city  use, 
and  is  not  intended  to  touch  upon  the  subject  of  domestic  filters. 
The  author  believes  that  domestic  filters,  however  well  designed, 
are,  in  the  hands  of  the  users,  a  delusion  and  a  snare ;  and  instead 
of  being  a  safeguard  against  water-borne  diseases,  they  really  en- 
courage the  growth  of  the  water  bacteria,  among  which  at  times 
may  be  pathogenic  organisms. 

The  tests  noted  in  Chapter  III.,  on  Bacterial  Contents  of 
Various  Waters,  is  therefore  the  only  reference  to  domestic  filters ; 
and  these  have  been  included  among  others  of  water  in  and  about 
the  city  of  Cincinnati. 

Continuous  sand  filtration  as  practiced  in  Europe  has  gone 
through  an  experience  of  nearly  fifty  years,  and  one  would  suppose 
that  this  length  of  time  should  be  sufficient  to  remove  the  matter 
from  the  domain  of  experiment  and  establish  it  in  the  domain  of 
fact.  Still,  curiously  enough,  there  are  some  who  discuss  sand  fil- 
tration as  practiced  abroad  very  much  as  they  do  the  subject  of 
air  navigation  and  the  mobile  perpetuum,  —  things  very  interesting 
in  themselves,  but  quite  impossible  of  any  practical  results.  This 
indifference  to  the  wonderful  performance  of  sand  filters  in  Euro- 
pean cities  is  a  bar  to  the  development  of  works  of  water  purifica- 
tion in  this  country,  and  is  the  cause  of  a  large  continuous  loss  of 
valuable  lives  and  much  physical  suffering,  eighty  to  ninety  per 
cent  of  which  might  be  averted  if  artificial  works  of  water  purifi- 
cation were  as  largely  used  in  this  country  as  they  are  abroad. 

Some  writers  in  their  enthusiasm  have  declared  that  sand  filters 
properly  constructed  and  operated  will  furnish  pure  water.  This 
is  a  mistake.  No  filter  operated  upon  a  practical  basis  has  ever 


132  THE   PURIFICATION  OF   WATER. 

furnished  pure  water ;  but  the  so-called  purified  water  is  so  much 
superior  to  the  unfiltered  water  that  it  will  meet  the  practical 
requirements  of  cities  and  communities  to-day,  and  when  the  time 
is  reached  that  people  demand  absolutely  pure  water,  methods  for 
furnishing  it  will  doubtless  be  forthcoming.  For  the  present,  and 
as  a  practical  method  of  water  purification,  filtration  may  be  re- 
garded as  entitled  to  full  credit  at  the  hands  of  city  officials  and 
water-works  managers. 

Filtration,  as  the  term  is  defined  and  generally  understood, 
consists  of  an  interception  or  straining  out  from  a  fluid  such  sus- 
pended matter  as  is  larger  in  some  dimension  than  the  pores  of 
the  filtering  medium.  The  action  is  supposed  to  be  purely  mechan- 
ical, and  the  efficiency  of  a  filter  will  be  measured  by  the  fineness 
or  coarseness  of  the  filtering  material.  The  filtration  of  water, 
however,  demonstrates  that  the  fineness  of  the  filtering  material 
(sand)  is  not  exactly  a  measure  of  the  efficiency,  and  the  finest 
or  smallest  grain  of  sand  does  not  always  give  the  best  results. 

This  fact,  then,  would  naturally  suggest  that  the  straining 
action  is  only  a  part  of  the  work  accomplished  by  the  filter;  and  in 
addition  to  the  interception  of  certain  suspended  matters  at  the 
surface  of  the  sand-bed,  some  other  forces  are  at  work  to  reduce 
the  suspended  matter,  including  the  bacteria,  in  the  water.  One 
of  these  forces  is  now  known  to  be  the  action  of  the  bacteria 
on  the  organic  matter.  This  is  called  the  biologic  action  of  the 
filter. 

All  the  common  species  of  bacteria  found  in  water  are  sapro- 
phytes, and  depend  for  subsistence  on  dead  organic  matter.  In 
fact,  the  bacteria  are  chiefly  concerned  in  the  destruction  of  this 
organic  matter,  and  its  conversion  into  harmless  nitrates.  The 
action  of  certain  well-known  forms  of  water  bacteria  upon  sloped 
agar,  is  seen  to  be  the  production  of  a  film,  or  expansion  so-called, 
of  its  products  of  vital  activity  over  the  surface,  and,  if  possessed 
of  anaerobic  properties,  in  the  body  of  the  agar.  This  expansion 
is  indicative  of  the  effect  and  propagation  of  the  bacteria  on  the 
food  material. 

The  bulk  of  the  suspended  matter,  including  the  bacteria  in 
water,  will  be  intercepted  at  the  surface  of  the  sand.  Here  the 


FILTRATION  OF   WATER  SUPPLIES.  133 

process  of  splitting  up  the  organic  matter  inio  its  nitrogenous 
and  carbonaceous  elements  is  continually  going  on ;  the  carbons 
going  off  as  carbon  dioxides  and  other  gases,  and  the  nitrogenous 
matters  being  converted  into  nitrous  and  nitric  acids,  which  in  turn 
unite  with  the  bases  in  the  water,  forming  nitrites  and  nitrates,  in 
themselves  harmless  products  of  bacterial  action. 

This  biologic  action  of  a  filter  is,  after  all,  its  most  important 
function.  The  simple  straining  process  of  a  bed  of  sand  or  of 
other  filtering  material,  while  competent  to  render  turbid  water 
clear,  could  have  but  little  effect  upon  the  bacteria,  because  many 
of  these  are  so  small  in  some  dimension  as  to  grow  through  a 
sand-bed  of  almost  any  practicable  fineness.  The  action  of  the 
organisms  in  the  water  on  the  organic  matter  results  in  the  pro- 
duction of  a  thin  semi-gelatinous  film  over  and  around  the  grains 
of  sand  in  the  upper  layers  of  a  bed,  which  in  due  time  becomes 
so  dense  as  to  clog  it,  and  require  a  high  head  to  force  the  desired 
amount  of  water  through  the  sand  ;  whereupon  such  sand-bed  is 
temporarily  taken  out  of  service,  the  water  drawn  down  some  dis- 
tance below  the  surface,  and  the  upper  fraction  of  an  inch  of  the 
sand  removed.  With  the  new  surface  of  sand  exposed,  the  filter 
is  ready  for  service  again. 

When  the  water  is  drawn  off  a  filter  for  renewal  of  the  surface 
of  the  sand-bed,  two  important  events  occur.  One  consists  of  the 
paring  off  of  a  thin  layer  of  the  clogged  sand  mentioned  above ; 
and  the  other  of  a  complete  or  partial  aeration  of  the  sand-bed,  by 
means  of  which  the  nitrifying  bacteria  in  the  bed  are  supplied  with 
air  (oxygen),  without  which,  according  to  the  authorities  who  have 
especially  studied  these  organisms,*  the  nitrifying  bacteria  would 
soon  perish,  and  their  functions  in  the  reduction  of  nitrogenous 
organic  matter  to  nitrous  and  nitric  acids  be  lost. 

All  sand  filters  are  therefore  intermittent  filters.  None  work 
continuously.  Each  time  the  water  is  drawn  down  below  the  sur- 
face of  the  sand-bed,  there  is  a  partial  aeration  of  the  sand;  and 
when  the  water  is  drawn  off  entirely,  during  the  operation  of  par- 
ing away  the  upper  one-half  (£)  inch  or  so  of  dirty  sand,  the  bed 
is  rested,  as  it  were,  and  complete  aeration  occurs. 

*  Winogradsky,  Warington,  Percy  Frankland,  Dr.  E.  O.  Jordan,  and  Mrs.  Ellen  H.  Richards. 


134  THE   PURIFICATION  OF   WATER. 

This  upper  dirty  layer  of  sand,  which  contains  inorganic  mat- 
ter intercepted  from  the  water,  and  the  products  of  vital  activity 
of  the  water  bacteria,  is  called  the  "  Schmutzdecke  "  by  Mr.  Piefke, 
who,  the  author  believes,  was  the  first  to  point  out  the  manner  in 
which  the  semi-gelatinous  film  was  formed,  and  how  it  consisted 
of  intercepted  matter  in  suspension,  and  organic  matter  in  process 
of  destruction  by  bacterial  agency. 

To  one  untutored  in  bacteriologic  work,  it  may  be  difficult  to 
understand  the  action  of  the  bacteria  on  nutrient  matter  in  water  ; 
but  to  bacteriological  students  it  is  sufficient  to  state  that  in  a  fil- 
ter the  action  of  the  bacteria  upon  suitable  food  material  found  in 
the  water  will  be  like  that  of  bacteria  cultivated  in  sterilized  arti- 
ficial media.  The  materials  found  in  water  may  be  more  or  less 
suitable  for  some  of  the  water  bacteria ;  and  those  which  find  the 
organic  matter  fitted  to  their  needs  will  flourish  on  the  surface  of 
a  sand-bed,  and  appropriate  to  their  support  such  matter  as  may  be 
found  in  suspension  or  intercepted  at  or  near  the  surface  of  the 
sand. 

It  is  abundantly  proven  that  the  bacteria  do  not  penetrate  the 
sand-bed  to  any  great  depth,*  and  the  surface  of  the  sand  where 
the  interception  of  suspended  matter  must  occur  is  also  the  prin- 
cipal seat  of  operations  of  the  bacteria  and  other  organisms  in  the 
water.  The  bacteria  are  not  the  only  forms  of  life  in  water,  and 
some  allowance  must  be  made  for  the  destructive  action  of  the 
infusoria  and  other  forms  of  aquatic  life  upon  the  organic  matter 
of  which  all  these  forms  are  themselves  a  part. 

The  following  diagram  and  description  showing  the  rate  at 
which  the  bacteria  grow  in  the  sand-bed  from  the  surface  down- 
ward, is  taken  from  Mr.  Gill's  paper  on  the  filters  at  the  Freder- 
ickshagen  Station  of  the  Berlin  Water-Works. 

"It  has  been  stated  above  that  the  number  of  bacteria  colonies  is  greatest 
at  the  surface  of  the  sand,  and  decreases  very  rapidly  in  successive  layers  be- 
neath. In  Fig.  G,  0,  .r,  z,  y,  represents  the  2-foot  deep  sand-layer  of  a  filter. 
If  with  0  as  origin,  and  distances  along  0,  x,  representing  depths  of  sand-layer, 
and  those  along  0,  j/,  numbers  of  bacteria  colonies  per  kilogram  of  sand,  the 

*  The  Filtration  of  the  Miiggel  Lake  Water  Supply,  Berlin,  by  Henry  Gill,  M.I.C.E., 
London,  1895,  p.  12. 


FILTRATION  OF   WATER  SUPPLIES. 


135 


60,000,000  bacteria  colonies  per  kilogram  of  the  ripe  sarfd  be  plotted  at  each 
of  the  depths  0,  4,  8,  12,  and  24  inches,  the  line  h,  w,  parallel  to  0,  x  is  arrived 
at.  The  hatched  strip  0,  x,  m,  h,  then  represents  the  ripe  condition  of  filter 
sand  after  long  use,  in  which  condition  a  powerful  water  current  and  attrition 
of  the  grains  against  each  other  fail  to  free  them  from  the  bacteria.  If  now, 
with  the  same  abscissae,  the  734,  190,  150,  92,  and  60  millions  be  plotted  as 
ordinates,  the  curve  m,  p,  q,  r,  is  arrived  at.  This  curve  exhibits  pictorially 
the  density  of  the  bacteria  colonies  in  the  various  layers  of  a  sand  filter  at  the 
close  of  a  period  of  service  when  it  gives  the  best  results." 


Surface  of  Sand  Bed 


24" Sand  Bed 


<5and 


tnin 
i 

i 


Gravel 
Fig.  6.    Diagram  Showing  Accumulation  of  Bacteria  in  Sand-Bed. 


The  "Schmutzdecke,"  or  film  of  intercepted  suspended  matter 
and  products  of  bacterial  action,  is  a  delicate  membrane  lacking  in 
consistency,  and  easily  broken  by  too  rapid  changes  of  pressure 
(head)  on  the  sand-bed ;  and  when  broken  bad  results  are  liable  to 
follow.  The  author  cannot  do  better  than  quote  again  from  Mr. 
Gill  upon  this  feature  of  sand  filtration.* 

"  Since  the  bacteria  are  liable  to  be  washed  downwards  by  a  stream  of 
greater  force  than  that  which  prevailed  when  they  came  into  contact  with  the 
sand  grains,  it  is  of  the  utmost  importance  to  avoid  an  increase  of  speed, 
especially  a  sudden  increase.  Mechanical  arrangements  must  be  adopted  to 
prevent  this,  and  it  must  be  impossible  that  any  filter  in  action  can  in  any  way 
affect  the  yield  of  the  neighboring  filter.  The  chief  cleansing  action  takes 
place  in  the  mud  deposit  on  the  surface  of  the  sand,  and  in  the  sand  immediately 
at  the  surface.  In  this  region  the  coating  of  deposit  is  soft,  and  with  its  dense 
population  requires  careful  and  tender  treatment  to  avoid  squeezing  out  the 
bacteria  by  undue  pressure.  It  is  obvious  that  as  soon  as  an  appreciable 


*   The  Filtration  of  the  Miiggel  Lake   Water  Supply,  Berlin,  by  Henry  Gill,  M.I.C.E., 
London,  1895,  p.  12. 


136  THE   PURIFICATION  OF   WATER. 

deposit  has  taken  place  on  the  sand  surface,  any  increase  of  '  head  '  must  be 
chiefly  caused  by  the  layer  of  this  deposit.  If  the  sand  beneath  is  not  abso- 
lutely homogeneous,  as  it  cannot  be,  any  increase  of  pressure  may  cause  a 
depression  and  a  tearing  of  the  mud-skin  on  the  less  dense  parts  of  the  surface 
of  the  sand.  Through  such  a  rupture  the  bacteria  are  at  once  washed  by  the 
increased  local  current  which  ensues  into  the  sand  beneath,  and  may  be  carried 
through  the  entire  layer.  Yet  a  gradual  increase  of  pressure  must  of  necessity 
take  place,  when  the  yield  is  to  be  constant,  in  order  to  overcome  the  increas- 
ing friction  of  the  passage  of  the  water  through  the  filtering  medium,  in  pro- 
portion as  its  insterstices  become  gradually  closed  by  the  deposit.  Nor  is  such 
increase,  if  gradual,  injurious,  provided  certain  limits  be  not  exceeded. 

Mr.  Gill  states  that  the  maximum  "  head  "  for  the  Miiggel  Lake 
filter  is  2  feet,  but  this  has  been  increased  in  other  instances  to 
5  or  6  feet  without  an  apparent  breaking  of  the  surface  film  on 
the  sand-bed. 

After  a  filter  has  been  scraped,  and  refilled  with  filtered  water 
from  below  to  the  surface  of  the  sand,  water  should  r3e  drawn  from 
the  settling-basin  onto  the  filter  to  the  full  depth  of  high-water 
mark,  and  allowed  to  stand  several  hours  before  any  flow  occurs 
from  the  filter.  This  interval  of  rest  will  be  in  continuation  of  the 
subsidence  of  the  suspended  matter  in  the  water,  and  will  assist  in 
the  formation  of  a  coat  of  slime  over  the  sand-bed  before  the  flow 
is  started.  After  the  water  has  remained  at  rest  for  a  few  hours 
over  the  sand-bed,  the  flow  should  be  started  cautiously,  at  a  low 
rate,  and  gradually  increased  until  the  maximum  allowable  rate  has 
been  attained. 

ACTION   OF  THE  INTERMITTENT  SAND   FILTER. 

In  the  continuous  sand  filter  substantially  the  whole  work  of 
purification  is  accomplished  at  or  near  the  surface  of  the  sand-bed. 
The  "  Schmutzdecke,"  or  dirty  cover,  which  is  regarded  by  foreign 
engineers  as  an  essential  of  proper  eand  filtration,  is  not  consid- 
ered of  special  importance  in  the  intermittent  filter.  In  this  it  is 
assumed  that  the  organic  matter  in  the  water  is  reduced  by  the 
action  of  the  bacteria  in  the  bed  of  sand  to  nitrous  and  nitric  acids, 
which  unite  with  the  bases  in  the  water,  forming  insoluble  and 
harmless  nitrites  and  nitrates;  This  work  is  chiefly  accomplished 
by  the  nitrifying  bacteria,  discovered  by  Winogradsky  in  the  soil 


FILTRATION  OF  WATER  SUPPLIES,  137 

at  Zurich,  and  by  Dr.  Jordan  and  Mrs.  Richards  in  the  sewage 
at  Lawrence,  Mass. ;  but  the  ordinary  water  bacteria  are  also  useful 
in  breaking  up  the  organic  matter  in  water  before  it  is  acted  upon 
by  the  nitrifiers. 

The  intermittent  filter  receives  the  water  for  a  number  of  hours 
or  days,  and  then  rests  for  a  number  of  hours  or  days,  until  the 
water  held  in  the  sand-bed  has  drained  away,  and  the  interstitial 
spaces  are  filled  with  air,  when  the  filter  is  supplied  with  water  as 
before. 

Thus,  while  the  action  is  intermittent  from  day  to  day,  it  other- 
wise is  continuous  in  operation,  the  scraping  and  cleaning  of  the 
sand  being  only  such  as  ca»  readily  be  done  during  the  short 
intervals  of  rest. 

In  the  intermittent  sand  filter  the  bed  of  sand  for  the  whole 
depth  is  supposed  to  act  in  the  work  of  water  purification,  while 
the  upper  one-half  inch  or  less  of  sand  is  known  in  the  continuous 
filter  to  be  concerned  in  the  reduction  of  the  bacterial  contents  as 
well  as  of  other  matters  held  in  suspension  by  the  water.  The 
operation  of  the  Lawrence,  Mass.,  filter,  since  it  was  put  in  regular 
service,  suggests  that  there  has  been  some  departure  from  the 
original  method  of  use,  and  that  in  the  days  of  continual  service, 
and  the  resting  and  scraping  of  the  sand-bed,  it  conforms  mose 
nearly  than  was  intended  to  the  method  of  operation  pursued  with 
sand  filters  abroad. 

By  the  thorough  and  frequent  aeration  of  the  sand-bed,  it  is  held 
by  the  designer  (Mr.  Mills)  that  there  will  be  a  "burning  up"  of 
the  organic  matter  intercepted  at  the  surface  and  in  the  depth 
of  the  filter,  and  by  proportioning  properly  the  duration  of  ser- 
vice and  rest,  with  a  complete  draining  of  the  bed  each  time  it  is 
rested,  all  organic  matter  will  be  consumed.  The  aeration  of  the 
sand-bed  is  intended  to  maintain  the  vitality  of  the  nitrifying 
bacteria,  which  are  the  organisms  concerned  in  the  final  destruc- 
tion of  the  organic  matter,  and  its  conversion  into  nitrites  and 
nitrates. 

It  is  the  theory  that  the  intermittent  filter  is  capable  of  con- 
tinuous renewal  by  the  forces  within  itself,  and  the  large  periodical 
expense  required  to  restore  the  sand-bed  of  the  continuous  filter  to 


138 


THE   PURIFICATION  OF    WATER. 


its  normal  condition  will  be  materially  reduced.  Enough  experi- 
ence has  not  been  had  with  this  system  of  filtration  to  express  an 
opinion  upon  its  adaptability  to  other  waters  than  that  of  the  Mer- 
rimac  River ;  but  both  in  the  bacterial  results  and  typhoid  rates  of 
Lawrence,  since  it  was  put  in  service  four  years  ago,  it  seems  not 
to  have  attained  the  high  standard  of  efficiency  reached  by  the 
continuous  sand  filters  of  Europe. 

Any  statement  heretofore  made  upon  the  operation  of  sand 
filters  is  assumed  to  be  the  natural  action  without  the  aid  of  ex- 
traneous materials  to  assist  in  the  precipitation  of  suspended  mat- 
ters, or  in  the  formation  of  a  coagulum  at  the  surface  of  the  sand. 
Aside  from  the  use  of  particles  of  iron  in  a  revolving  cylinder 
(Anderson  process),  it  is  not  known  that  any  artificial  agency  is 
relied  upon  to  insure  the  successful  operation  of  sand  filters  in 
Europe. 

From  a  knowledge  of  natural  filtration  as  it  occurs  in  the  drift, 
it  is  easy  to  perceive  that  artificial  sand  filtration  may  be  made  to 
accomplish  results  far  superior  to  natural  filtration  as  it  some- 
times occurs.  Thus  the  size  and  uniformity  of  the  sand-grains,  the 
effective  head,  and  rate  of  flow  through  the  sand-bed,  may  be  so 
proportioned  that  the  resultant  filtrate  is  equal  in  purity  to  spring 
or  deep  well  water.  And  this  result  can  be  obtained,  not  seldom, 
but  at  all  times,  and  without  regard  to  the  original  condition  of  the 
water.  Assuming  that  the  typhoid  fever  death  rate  is  a  correct 
index  of  the  quality  of  a  public  water  supply,  then  it  appears  that 
filtration  can  produce  a  water  which  will  rival  the  purest  of  natural 
waters. 

The  water  of  Vienna  and  Munich  is  mountain  spring  water, 
not  surpassed  by  any,  and  equaled  by  that  of  few  cities  of  the 
world.  The  typhoid  rates  by  the  author's  scale  (Chapter  V.)  for 
these  cities  since  1890  have  been:  — 

DEATH   RATES  FROM  TYPHOID   FEVER  PER  100,000  OF  POPULATION   LIVING. 


YEARS, 

1890. 

1891. 

1892. 

1893. 

1894. 

1895. 

1896. 

AVERAGE. 

Vienna, 

9 

6 

8 

7 

5 

6 

5 

6.55 

Munich, 

8 

7 

8 

15 

2.5 

3 

3 

5.94 

FILTRATION  OF    WATER  SUPPLIES. 


139 


Omitting  the  rate  for  1893  for  Munich,  when  there  appears 
to  have  been  an  unwarranted  increase  in  the  typhoid  rates,  the 
average  for  the  other  six  years  becomes  4.4. 

The  water  of  Rotterdam  and  Berlin  is  filtered,  the  first  from 
the  River  Maas,  and  the  second  from  the  Rivers  Spree  and  Havel, 
both  of  which  have  received  sewage  and  surface  drainage  from 
urban  and  rural  territory  before  the  water  reaches  the  intakes  of 
these  works. 

DEATH   RATES    FROM   TYPHOID   FEVER  PER   100,000  OF   POPULATION   LIVING. 


YEARS, 

1890. 

1891. 

1892. 

1893. 

1894. 

1895. 

1896. 

AVERAGE. 

Rotterdam, 

6 

4 

6 

5 

4.8 

2 

12 

5.7 

Berlin, 

9 

10 

8 

9 

4 

5 

5 

7.14 

Note  the  fact  that  the  death  rate  for  Rotterdam  is  lower  than 
for  either  Vienna  or  Munich.  Note  also  that  the  comparison  is  not 
between  cities  of  one  country  where  the  consumption  of  beer  and 
other  beverages  is  high,  and  of  another  country  where  from  mod- 
esty, if  for  no  other  reason,  we  must  claim  that  the  consumption 
of  beverages  other  than  water  is  low. 

Aside  from  the  fact  of  equal  quality  as  shown  by  comparison 
of  spring  and  filtered  waters,  the  theory  of  sand  filtration,  properly 
studied,  leads  to  the  conclusion  that  water  of  more  uniform  quality 
can  be  had  from  artificial  filters  than  from  irregular  and  scattered 
sand-beds  as  found  in  the  drift,  in  some  of  which  the  size  and 
irregularity  of  sand-grain  and  position  of  the  sand-bed  are  not  cal- 
culated for  proper  filtration.  Spring  water  and  well  water  may  be 
pure,  but  we  cannot  state  with  assurance  how  it  has  been  made 
pure  ;  while  with  filtered  water  we  know  how  purity,  so-called,  has 
been  obtained,  and  by  repeating  the  process  of  purification  we  can 
reproduce  the  quality  of  filtrate. 

The  insufficiency  of  natural  filtration  through  the  drift  is  well 
recognized  by  those  who  have  given  the  matter  serious  considera- 
tion. Dr.  Drown,  in  the  Report  of  the  Massachusetts  State  Board 
of  Health  for  1891,  p.  355,  says:  — 


"  Although  water  badly  contaminated  with  sewage  or  the  wastes  of  human 
life  may  be  purified  by  thorough  nitration  so  as  to  be  free  from  organic  matter 


140  THE  PURIFICATION  OF   WATER. 

and  bacteria,  yet  in  cases  of  ground  waters  of  this  origin  and  character  we  sel- 
dom feel  complete  security  that  the  conditions  of  perfect  filtration  will  always 
exist.  A  long-continued  rainfall,  for  instance,  may  result  in  more  rapid  filtra- 
tion, and  consequently  less  perfect  purification  ;  or  the  creation  of  new  sources 
of  contamination  nearer  the  spring  may  result  in  its  dangerous  pollution. 

"It  is  for  such  reasons  that  a  certain  suspicion  always  attaches  to  ground 
waters  which  have  at  any  time  in  their  history  been  seriously  polluted.  The 
use  of  ground  waters,  whether  springs  or  wells,  in  built-up  communities,  should 
therefore  be  avoided ;  for  we  have  no  control  over  the  conditions  of  filtration, 
and  have  no  means  of  knowing  (except  by  constant  vigilance  in  the  examina- 
tion of  the  water)  when  a  water  hitherto  well  purified  may  become  injuriously 
impure.  The  danger  from  the  use  of  ground  waters  in  populous  regions  in- 
creases v/ith  the  increase  of  population,  and  with  the  nearness  of  the  sources 
of  pollution  to  the  spring  or  well." 

The  methods  of  water  purification  which  have  given  such 
excellent  results  in  cities  of  Europe  are  generally  sedimentation 
for  a  few  days  in  large  reservoirs,  combined  with  slow  filtration 
through  beds  of  sand ;  and  in  some  situations,  like  that  of  Berlin 
at  Lake  Miiggel,  where  there  is  usually  but  little  turbidity  to  the 
water,  it  is  at  times  pumped  direct  from  the  lake  to  the  filters. 

Sedimentation  is  accomplished  in  reservoirs  which  will  hold 
from  a  day  to  several  days'  supply.  While  at  a  state  of  rest  in 
these  reservoirs,  much  of  the  suspended  matter  which  imparts 
color  to  the  water  will  be  precipitated,  and  form  layers  of  mud  on 
the  bottom  and  sides  of  the  basin. 

While  a  few  days'  subsidence  of  turbid  polluted  water  may 
have  no  large  influence  upon  its  quality,  it  will  remove  much  of 
the  suspended  matter  which  otherwise  will  clog  a  sand  filter,  and 
reduce  its  term  and  efficiency  of  service. 

Careful  study  of  the  subject  of  sand  filtration  has  led  to  the 
opinion  that  it  is  possible  to  have  the  sand  so  fine  and  the  rate 
of  filtration  so  slow  that,  theoretically,  all  suspended  matter,  in- 
cluding the  bacteria  will  be  arrested  on  or  in  the  sand-bed.  But 
this  would  require  enormous  areas  of  filter  surface,  with  limited 
commercial  efficiency,  and  the  cost  of  water  so  obtained  would 
be  prohibitory  on  a  large  scale. 

In  order,  however,  to  approach  as  nearly  as  practicable  the 
ideal  condition  of  filtrate  at  a  reasonable  cost,  it  is  desirable  that 


FILTRATION  OF   WATER  SUPPLIES.  141 

all  the  heavier  matter  should  be  removed  by  subsidence  before  the 
water  is  put  on  the  filters.  Hence  the  use,  in  the  water-works  of 
London,  Hamburg,  and  other  foreign  cities,  of  subsiding  reservoirs 
in  which  the  water  is  stored  for  several  hours  or  days  before  the 
process  of  filtration  begins. 

It  is  not  possible  to  make  a  sewage-polluted  water  fit  for 
drinking-purposes  by  subsidence  alone,  excepting  the  water  is 
permitted  to  remain  in  a  wholly  quiescent  state  in  large,  deep 
reservoirs  for  many  months  or  years ;  a  condition  altogether  im- 
practicable for  most  cities  ;  while  subsidence  for  a  few  hours  or 
days  will  reduce  the  suspended  matter  and  silt  in  most  turbid 
waters  to  a  state  which  will  admit  of  the  use  of  comparatively  fine 
sand  in  the  filters,  and  rates  of  delivery  higher  than  the  average 
of  European  practice.  The  Engineer  Commission  on  the  Im- 
provement of  the  Water-Works  of  the  city  of  Cincinnati,  proposed 
a  rest  of  the  Ohio-river  water  in  subsiding  reservoirs  for  four  days 
before  it  was  drawn  off  to  the  filters. 

The  time  allowed  for  sedimentation  before  the  water  is  thrown 
on  the  filters  varies  in  different  cities,  and  sometimes  is  controlled 
by  financial  rather  than  hygienic  considerations.  The  following 
table  contains  the  data  upon  this  subject,  from  a  few  of  the  works 
abroad  which  combine  subsidence  with  filtration  :  — 

TIME  ALLOWED   FOR  SEDIMENTATION. 


LONDON, 

Chelsea  Works, 

12.0  days. 

West  Middlesex, 

5.6     « 

Southwark, 

4.1     « 

Grand  Junction, 

3.3     « 

Lambeth, 

6.0     « 

New  River, 

4.4     « 

East  London, 

15.0     « 

HAMBURG, 

19-30  hours. 

ROTTERDAM, 

24     « 

BERLIN,  Frederickshagen  Works,        24     « 

The  views  of  English  engineers  at  present  distinctly  favor  sed- 
imentation of  surface  waters  previous  to  filtration  ;  and  the  new 
works  proposed  by  Sir  A.  R.  Binnie  for  the  supply  of  London, 
notwithstanding  the  water  impounded  from  the  Welsh  sources  is 


142  THE   PURIFICATION  OF   WATER. 

naturally  of  very  high  quality,  contemplates  nitration  of  this  water 
before  it  is  distributed  to  the  consumers. 

In  his  report  on  the  new  sources  of  supply  proposed  for 
London,  Mr.  Binnie  says  :  — 

"  Although  it  will  be  seen  from  the  chemist's  analyses  of  the  water  of  the 
Usk,  the  Yrfon,  the  Towy,  the  Wye,  etc.,  that  the  waters  in  their  natural  state 
are  of  greater  purity  and  contain  less  solid  matter  than  the  London  water 
after  nitration,  and  although  these  waters  will  be  stored  and  be  subjected  to 
subsidence  in  the  large  reservoirs  which  I  have  described,  and  in  some  cases 
will  be  decanted  or  drawn  off  from  one  reservoir  into  another,  yet  I  consider 
that  when  all  precautions  are  taken,  the  water  should  be  filtered  before  deliv- 
ering to  the  consumer." 

According  to  certain  principles  formulated  by  the  Imperial 
Board  of  Health,  Berlin  (1893),  the  rate  of  nitration  should  not 
exceed  4  inches  vertical  .per  hour,  or  8  feet  per  day,  which  corre- 
sponds to  a  daily  rate  per  acre  of  2,606,630  U.  S.  gallons.  From 
some  experiments  by  the  late  Mr.  W.  Kiimmel,  engineer  of  the 
Altona,  Germany,  Water- Works,*  at  rates  of  filtration  of  4,  8,  and 
16  feet  vertical  per  day,  he  obtained  the  best  bacterial  results  from 
the  higher  rates,  as  indicated  by  the  following  table  :  — 

1,303,315  U.  S.  gallons  per  acre  per  day  =  11  to  97  colonies  per  c.  c. 
2,606,630  «  «  «        =    5  to  79 

5,213,260  «  «  "        =    7  to  72        « 

Mr.  Kiimmel  did  not  regard  8  feet  per  day  as  "beyond  doubt 
the  maximum  of  safe  filtration;"  he  thought  though,  that  "the 
danger  of  a  trespassing  pathogenic  organism  is  much  more  unlikely 
at  the  lower  than  at  the  higher  rates,  and  that  the  best  velocity 
was  not  the  same  for  all  waters."  He  felt  confident  "that  the 
difference  in  the  mineral,  vegetable,  and  animal  admixtures  is  of 
high  importance  in  this  question,"  and  that  we  should  endeavor  to 
ascertain  the  best  rate  for  each  separate  water  and  water-works. 

From  the  latest  published  Annual  Report  of  the  Massachusetts 
State  Board  of  Health  (1895),  the  following  notes  from  the  exper- 
imental filters  at  the  Lawrence  station  are  taken  :  — 

*   Transactions  American  Society  of  Civil  Engineers,  vol.  xxx.,  p.  333. 


FILTRATION  OF   WATER   SUPPLIES. 


143 


INTERMITTENT   SAND    FILTERS. 


AVERAGE 

RATE  OF  FILTRATION. 

BACTERIA 

BACTERIA 

PERCENTAGE  OF 

GALLONS  PER  ACRE  PER  DAY. 

PER    C.  C.  IN 

PER  C.  C.   IN 

BACTERIA 

RIVER  WATER. 

FILTRATE. 

REMOVED. 

2,000,000 

11,600 

29 

99.75 

2,500,000  to  5,000,000 

16,300 

137 

99.16 

5,000,000  to  7,000,000 

11,600 

72 

99.38 

CONTINUOUS   SAND   FILTERS. 


AVERAGE 

AVERAGE 

RATE  OF  FILTRATION. 

BACTERIA 

BACTERIA 

PERCENTAGE  OF 

GALLONS  PER  ACRE  PER  DAY. 

PER    C.  C.  IN 

PER  C.  C.  IN 

BACTERIA 

RIVER  WATER. 

FILTRATE. 

REMOVED. 

1,000,000  to    2,500,000 

13,950 

72 

99.49 

2,500,000  to    5,000,000 

18,220 

273 

98.56 

5,000,000  to    7,000,000 

11,600 

73 

99.37 

7,000,000  to  10,000,000 

16,500 

130 

99.22 

The  average  results  given  in  the  table  were  obtained  with  sands 
varying  in  "  effective  size"  from  0.14  to  0.48  mm.,  and  "uniform- 
ity coefficient "  from  1.6  to  3.7,  while  the  thickness  of  sand-bed 
varied  from  60  to  7  inches.  Considering  the  efficiencies  of  the 
filters  with  sand-beds  not  less  than  48  inches  in  thickness,  the  5 
intermittent  filters  for  rates  of  filtration  from  2,000,000  to  6,600,- 
000  gallons  per  acre  per  day  gave  an  average  bacterial  reduction 
of  99.32  per  cent,  while  the  8  continuous  filters  for  rates  of  filtra- 
tion from  2,000,000  gallons  to  8,200,000  gallons  per  acre  per  day 
gave  an  average  bacterial  reduction  of  99.32  per  cent.* 

The  influence  of  rate  of  filtration  on  the  organic  matter  and 
bacterial  contents  of  the  Zurich  filtered  water  is  shown  by  Dr.  A. 
Bertschinger  of  the  Municipal  Laboratory  of  Zurich,  in  the  follow- 
ing table :  — 


CHEMICAL  QUANTITIES 

RATE  OF  FILTRATION  PER  ACRE  PER  DAY  IN  U.  S.  GALLONS. 

FILTERED  WATER. 

4,356,000. 

5,227,200. 

8,712,000. 

16,262,400. 

21,489,600. 

Organic  matter, 

1.65 

1.69 

1.70 

1.70 

2.02 

Free  ammonia, 

0.0007 

0.0008 

0.0004 

0.0004 

0.0006 

Albuminoid  ammonia, 

0.0028 

0.0027 

0.0027 

0.0027 

0.0037 

Bacteria  per  c.  c.  in  filtrate, 

20 

31 

22 

15 

18 

*   Twenty- seventh  Annual  Report  Massachusetts  State  Board  of  Health,  p.  505. 


144 


THE  PURIFICATION  OF   WATER. 


Commenting  on  these  results,  Mr.  Preller  *  says  (adapting  his 
figures  to  U.  S.  gallons  and  rates  per  acre  per  day)  :  — 

"  These  results  show,  therefore,  that,  provided  the  filter-beds  are  in  efficient 
working  order,  neither  the  chemical  nor  the  bacteriological  purity  of  the  filtered 
water  is  impaired  by  increasing  the  rate  of  percolation  from  5,953,200  to 
16,262,400  U.  S.  gallons  per  acre  per  day,  a  fact  which  is  at  variance  with  the 
view  advanced  elsewhere,  that  the  mean  rate  of  percolation  for  sand-filters 
should  be  limited  to  3,194,400  U.  S.  gallons  per  acre  per  day." 

According  to  Mr.  Schroder,  the  number  of  bacteria  in  the  un- 
filtered  Elbe  water  at  Hamburg  ranges  from  800  to  3,000,  while 
the  filtered  water  seldom  contains  above  30  colonies  per  cubic 
centimeter,  and  at  times  is  as  low  as  20  colonies  per  cubic  cen- 
timeter, showing  a  reduction  of  97.5  to  99.0  per  cent  in  the 
bacterial  contents  of  the  raw  water. 

The  following  tables  from  Dr.  E.  Frankland's  f  bacterial  an- 
alysis of  the  water  supplied  by  the  London  companies  from  the 
Rivers  Thames  and  Lea,  are  very  interesting  when  viewed  from 
the  standpoint  of  artificial  water  purification  upon  a  large  scale. 

COMPANIES  WHICH   TAKE   WATER  FROM  THE   RIVER  THAMES. 
CHELSEA  WATER  COMPANY. 
BACTERIA    PER   C.    C.    OF   WATER. 


MONTH. 

UNFILTERED 
WATER. 

AFTER  12  DAYS' 
STORAGE. 

AFTER 
FILTRATION. 

January, 

11,560 

1,360 

20 

February, 

26,800 

460 

44 

March, 

18,000 

240 

28 

April, 

7,520 

Lost. 

4 

May, 

2,060 

140 

24 

June, 

6,760 

1,150 

178 

July, 

2,220 

420 

20 

August, 

1,740 

200 

18 

September, 

4,300 

140 

2 

October, 

39,760 

340 

8 

November, 

8,560 

280 

12 

December, 

160,000 

854 

55 

Average, 

24,107 

508 

34 

Average  percentage  of  reduction  by  subsidence,  97.85 

Average  percentage  of  reduction  by  subsidence  and  filtration,     99.86 

*  Zurich  Water  Works,  C.  P.  Du  R.  Preller,  London,  1892,  p.  26. 

t  Annual  Summary  of  Vital  Statistics,  London,  1896,  p.  Ixxiv.,  et  seq. 


FILTRATION  OF   WATER  SUPPLIES. 


145 


WEST   MIDDLESEX   COMPANY. 
BACTERIA    PER   C.    C.    OF   WATER. 


MONTH. 

UNFILTERED 
WATER. 

AFTER  5.6  DAYS' 
STORAGE. 

AFTER 
FILTRATION. 

January, 

11,560 

3,460 

44 

February, 

26,800 

1,820 

16 

March, 

18,000 

2,340 

24 

April, 

7,520 

720 

20 

May, 

2,060 

280 

4 

June, 

.      6,760 

1,000 

301 

July, 

2,220 

680 

8 

August, 

1,740 

300 

6 

September, 

4,300 

120 

14 

October, 

39,760 

740 

30 

November, 

8,560 

5,520 

25 

December, 

160,000 

26,760 

120 

Average, 

24,107 

3,605 

si 

Average  percentage  of  reduction  by  subsidence,  85.05 

Average. percentage  of  reduction  by  subsidence  and  nitration,     99.79 


SOUTHWARK    AND    VAUXHALL    COMPANY. 
BACTERIA    PER   C.    C.    OF    WATER. 


MONTH. 

UNFILTERED 
WATER. 

AFTER  4.1  DAYS' 
STORAC.E. 

AFTER 
FILTRATION. 

January, 

11,560 

.    . 

32 

February, 

26,800 

234 

March, 

18,000 

.    . 

102 

April, 

7,520 

.    . 

1,116 

May, 

2,060 

36 

June, 

6,760 

.    . 

24 

July, 

2,220 

.    . 

188 

August, 

1,740 

.    . 

12 

September, 

4,300 

.    . 

68 

October, 

39,760 

.    . 

16 

November, 

8,560 

142 

December, 

160,000 

920 

8,020 

Average, 

24,107 

832.5 

Average  percentage  of  reduction  by  filtration  alone, 


96.55 


146 


THE  PURIFICAl^ION  OF   WATER. 


GRAND   JUNCTION   COMPANY. 
BACTERIA   PER   C.    C.    OF    WATER. 


MONTH. 

UNFILTERED 
WATER. 

AFTER  3.3  DAYS' 
STORAGE. 

AFTER 
FILTRATION'. 

January, 

11,560 

290 

28 

February, 

26,800 

400 

83 

March, 

18,000 

380 

97 

April, 

7,520 

1,110 

112 

May, 

2,060 

540 

56 

June, 

6,760 

567 

376 

My, 

2,220 

410 

32 

August, 

1,740 

510 

21 

September, 

4,300 

360 

63 

October, 

39,760 

740 

49 

November, 

8,560 

1,580 

110 

December, 

160.000 

38,000 

1,106 

Average, 

24,107 

3,741 

178 

Average  percentage  of  reduction  by  subsidence,  84.48 

Average  percentage  of  reduction  by  subsidence  and  filtration,     99.20 


LAMBETH  COMPANY. 
BACTERIA    PER   C.    C.    OF    WATER. 


MONTH. 

UNFILTERED 
WATER. 

AFTER  6.0  DAYS' 
STORAGE. 

AFTER 
FILTRATION. 

January, 

11,560 

6,560 

56 

February, 

26,800 

13,380 

56 

March, 

18,000 

5,120 

40 

April, 

7,520 

5,340 

12 

May, 

2,060 

1,080 

8 

June, 

6,760 

1,280 

130 

July, 

2,220 

1,340 

20 

August, 

1,740 

600 

60 

September, 

4,300 

1,080 

30 

October, 

39,760 

4,660 

12 

November, 

8,560 

2,920 

24 

December, 

160,000 

56,000 

116 

Average, 

24,107 

8,280 

47 

Average  percentage  of  reduction  by  subsidence,  65.65 

Average  percentage  of  reduction  by  subsidence  and  filtration,     99.81 


FILTRATION  OF   WATER   SUPPLIES. 


147 


COMPANIES    WHICH    TAKE    WATER    FROM    THE  fclVER    LEA. 

NEW   RIVER    COMPANY. 
BACTERIA   PER    C.    C.    OF    WATER. 


MONTH. 

UNFILTEKED 
WATER. 

AFTER  4.4  DAYS" 
STORAGE. 

AFTER 
FILTRATION. 

January, 

2,510 

1,040 

31 

February, 

2,080 

1,580 

31 

March, 

4,240 

1,820 

11 

April, 

1,340 

500 

4 

May, 

1,340 

300 

7 

June, 

1,640 

420 

17 

J«iy, 

1,500 

480 

12 

August, 

840 

340 

67 

September, 

2,540 

600 

16 

October, 

4,400 

820 

7 

November, 

3,200 

4,880 

69 

December, 

14,540 

7,480 

266 

Average, 

3,347 

1,693 

45 

Average  percentage  of  reduction  by  subsidence,  49.42 

Average  percentage  of  reduction  by  subsidence  and  filtration,    98.65 


EAST   LONDON   COMPANY. 
BACTERIA    PER    C.    C.    OF    WATER. 


MONTH. 

UNFILTERED 
WATER. 

AFTER  15  DAYS' 
STORAGE. 

AFTER 
FILTRATION. 

January, 

6,720 

3,140 

68 

February, 

7,880 

1,600 

69 

March, 

20,640 

1,460 

49 

April, 

Lost. 

Lost. 

52 

May, 

8,180 

1,180 

81 

June, 

11,720 

2,340 

208 

July, 

2,680 

1,520 

43 

August, 

6,020 

2,140 

68 

September, 

32,000 

2,160 

41 

October, 

12,220 

1,460 

53 

November, 

10,880 

3,200 

62 

December, 

80,000 

13,420 

145 

Average, 

18,085 

3,056 

78 

Average  percentage  of  reduction  by  subsidence,  83.10 

Average  percentage  of  reduction  by  subsidence  and  filtration,    99.56 


148 


THE   PURIFICATION  OF   WATER. 


PERCENTAGE   OF   BACTERIA   REMOVED. 


WATER  COMPANY. 

No.  OF  DAYS  OF 
SUBSIDENCE. 

BY 

SUBSIDENCE. 

BY  SUBSIDENCE 
AND  FILTRATION. 

Grand  Junction, 

3.3 

84.48 

99.26 

New  River, 

4.4 

49.42 

98.65 

West  Middlesex, 

5.6 

85.05 

99.79 

Lambeth, 

6.0 

65.65 

99.81 

Chelsea, 

12,0 

97.85 

99.86 

East  London, 

15.0 

83.10 

99.56 

Southwark  and 

Percentage  of  Bacteria  removed  by  Fil- 

Vauxhall, 

.  tration  without  Subsidence. 

96.55 

The  preceding  tables  have  been  given  in  some  detail  in  order 
to  discuss  the  numbers  of  bacteria  in  the  water  after  filtration. 
The  first  observation  which  one  will  naturally  make  is  the  extreme 
variation  of  results  for  different  months  by  the  same  company, 
and  for  the  same  months  by  the  different  companies.  Keeping  in 
view  the  London  standard  of  bacterial  contents  of  potable  water, 
—  i.e.,  100  colonies  per  cubic  centimeter,  —  it  appears  that  all  of 
the  companies  complied  with  the  standard  for  the  month  of  Janu- 
ary. Only  one  of  the  seven  companies  (Southwark)  failed  to 
comply  with  the  required  standard  for  February ;  and  only  one 
company,  the  Southwark  again,  failed  to  bring  the  bacterial  con- 
tents of  the  filtrate  within  the  prescribed  limit  for  the  month  of 
March. 

The  record  of  the  Southwark  Company  indicates  very  bad 
work  for  several  months,  and  as  an  average  for  the  year,  and  is 
to  be  accounted  for  only  upon  the  ground  of  insufficient  filter 
capacity,  or  gross  negligence  in  the  manipulation  of  the  filters. 
Once  only  did  the  Chelsea  and  New  River  Companies,  and  twice 
only  during  the  year  did  the  West  Middlesex,  Lambeth,  and  East 
London  Companies  pass  the  bacterial  limit,  while  the  work  of  the 
Southwark  and  Grand  Junction  Companies  for  the  year  was  gen- 
erally very  poor. 

With  the  exception  of  the  Chelsea  Company,  the  work  of  the 
filters  for  December  was  not  up  to  the  standard  of  London  water. 
Referring  to  the  Chelsea  Company,  and  omitting  the  bad  work  of 
the  filters  for  June,  the  average  for  the  other  eleven  months  was 


FILTRATION  OF   WATER   SUPPLIES.  149 

21.4  bacteria  per  cubic  centimeter,  of  filtered  water,  at  times  fall- 
ing so  low  as  2  and  never  exceeding  55.  Neglecting  the  bad  work 
of  the  West  Middlesex  filters  for  the  months  of  June  and  Decem- 
ber, the  average  for  the  other  ten  months  was  19.1,  the  lowest 
count  being  4,  and  the  highest  count  44  bacteria  per  cubic  centi- 
meter. 

An  examination  of  all  the  tables  reveals  the  fact  that  four  of 
the  companies  at  times  brought  the  bacterial  condition  of  the  water 
down  to  8  or  less  per  cubic  centimeter  of  the  filtrate,  and  since 
these  very  encouraging  exhibits  do  not  always  occur  simultane- 
ously by  months,  it  must  be  credited  to  management  of  the  filters 
or  favorable  company  conditions,  rather  than  to  conditions  prevail- 
ing in  the  unfiltered  waters. 

It  is  apparent  from  the  tables  that  the  performance  of  the 
filters  of  the  London  works  for  the  winter  months  is  in  some 
instances  very  unsatisfactory,  and  this  must  be  due  to  a  cause 
which  is  susceptible  of  remedy.  If  it  is  chargeable  to  uncovered 
filters,  then  covering  should  be  resorted  to.  But  the  Hamburg 
authorities  assure  the  author  that  they  have  been  able  with  un- 
covered filters,  and  by  an  ingenious  device  for  scraping  the  sand 
under  the  ice-cake  (see  Fig.  26)  which  forms  in  their  climate,  to 
keep  the  bacteria  in  the  filtered  water  down  to  30  per  cubic  cen- 
timeter. It  is  well  known  that  the  winters  are  more  rigorous 
in  Hamburg  than  in  London  ;  and  if  it  be  possible  to  satisfy  the 
hygienic  requirements  in  Hamburg  during  the  winter,  it  surely 
should  be  possible  to  do  so  in  London. 

It  will  also  be  noticed  that  the  low  bacterial  counts  in  the 
filtrate  do  not  always  follow  the  lower  counts  in  the  unfiltered 
river  water ;  thus,  the  Chelsea  filters  were  successful  in  reducing 
the  number  of  bacteria  in  the  water  to  4  per  cubic  centimeter 
with  7,520,  and  to  2  per  cubic  centimeter  with  4,300  in  the  ap- 
plied water ;  when  with  only  1,740  and  2,220  colonies  in  the  river 
water,  the  bacteria  in  the  filtrate  rose  to  18  and  20  per  cubic  cen- 
timeter. 

For  the  West  Middlesex  Company  the  conditions  seem  to 
change  somewhat,  the  lower  counts  of  bacteria  in  the  river  water 
being  followed  by  lower  counts  in  the  filtrate.  This  is  not  always 


150  THE  PURIFICATION  OF   WATER. 

true,  even  for  this  company  :  for  with  26,800  bacteria  per  cubic 
centimeter  in  the  river  water,  the  bacteria  in  the  filtrate  were  as 
low  as  16  per  cubic  centimeter  ;  while  with  only  4,300  in  the  river 
water,  the  bacteria  in  the  filtrate  were  14  per  cubic  centimeter  of 
the  water.  The  cause  of  these  variations  and  apparent  vagaries 
may  be  found  in  the  relative  condition  of  the  filters  in  service 
during  the  respective  months.  If  the  bacterial  examinations  hap- 
pened shortly  after  one  or  more  filters  had  been  cleaned,  the 
counts  in  the  filtrates  might  be  relatively  high  ;  while  if  the  ex- 
amination had  just  preceded  the  cleaning  of  a  filter,  the  count 
might  be  relatively  low. 

Aside  from  the  poor  work  accomplished  at  times  by  the  Lon- 
don filters,  it  is  manifest  that  filtration,  properly  conducted,  can 
produce  remarkable  changes  in  the  bacterial  contents  and  quality 
of  sewage-polluted  waters.  The  general  results  as  shown  by  the 
tables  indicate  marvelous  possibilities  which  can  be  attained  by 
filtration  under  a  rigorous  discipline  upon  the  part  of  the  health 
authorities,  and  a  proper  accountability  upon  the  part  of  the  water 
companies. 

Failure  to  attain  a  low  bacterial  condition  of  the  filtrate,  as  we 
have  seen,  is  not  due  to  the  weather,  nor  to  the  bacterial  con- 
tents of  the  unfiltered  water,  but  to  causes  which  an  inflexible 
regimen  would  speedily  remove.  A  review  of  the  seven  water- 
works of  London  which  take  their  supply  from  rivers  would  be 
unfair  if  it  failed  to  state  the  fact  that  these  companies  were 
hard  pressed  at  times  to  secure  the  required  quantity  of  water ; 
and  it  is  doubtless  true,  that  if  the  supply  of  water  from  the 
Thames  and  River  Lea  was  at  all  times  ample,  and  not  a  matter 
of  grave  concern,  the  English  engineers  would  undertake  to  sup- 
ply a  filtrate  which  should  never  exceed  the  prescribed  standard 
of  bacterial  contents,  and  usually  be  lower  than  that  of  average 
spring  waters. 

The  diagram  on  page  151  contains,  to  uniform  scale,  (1)  the 
depth  or  thickness  of  finer  sand-bed  ;  (2)  the  rate  in  imperial 
gallons  per  acre  per  day ;  and  (3)  the  percentage  of  bacteria  in  the 
applied  water  removed  by  filtration, — for  each  of  the  seven  Lon- 
don companies  which  filter  their  water  supplies.  The  solid  black 


FILTRATION  OF   WATER  SUPPLIES. 


151 


surfaces  show  the  thickness  of  sand-beds ;  the  finely  hatched  sur- 
faces show  the  rate  of  nitration  per  acre  per  day ;  and  the  coarsely 


hatched  surfaces  the  percentage  of  bacterial  efficiency.     The  ordi- 
nates  originate  at  a  common  zero  plane. 


152 


THE   PURIFICATION  OF   WATER. 


The  following  very  interesting  table  is  taken  from  Mr.  F.  A. 
Meyer's  paper*  on  the  Hamburg  Water-Works  (p.  23)  :  — 

NO.   OF    BACTERIA   PER   C.   C.   OF   WATER   AT   VARIOUS   POINTS   OF   THK 
HAMBURG  WATER-WORKS. 


SOURCE  OF  SAMPLE. 

BACTERIA  PER  C.  C. 
OF  WATER. 

Dec.  23,  1893 

Jan.  17,  1894 

New  intake  from  River  Elbe,  Billwarder  Island, 

1,665 

1,953 

From  settling-basins, 

674 

1,031 

From  main  conduit  to  filters,            "             " 

909 

1,053 

Unfiltered  water  from  Filter  No.     1,  Kalte  Hofe, 

818 

.  . 

"                 "             "     No.    3,             " 

1,094 

"     No.  19, 

782 

"    No.  20, 

.  . 

1,061 

Filtered   water    from    Filter  No.     1,             " 

18 

.  . 

"     No.     2, 

.  . 

33 

"                 "             "    No.    3,             " 

.  . 

31 

"                 "             "    No.    4,             " 

8 

.  . 

"                 "             "    No.    5,             " 

18 

.  . 

"                 "             "    No.     6,             " 

. 

21 

«                 «             «    No>    7^ 

7 

"                "            "    No.    8,             " 

.  . 

35 

"                 "             "    No.  11, 

33 

28 

"                 "             "    No.  12,             " 

45 

30 

"    No.  15, 

.  . 

.  . 

"    No.  16, 

24 

16 

"                 "             "    No.  17,             " 

29 

14 

"    No.  18, 

7 

4 

"    No.  19, 

11 

9 

"                 «'             "    No.  20,             " 

.  . 

18 

"     No.  21,             " 

.  . 

"                 "             "    No.  22,  t           " 

.  . 

.  . 

From  the  new  main  collecting  channel,         " 

19 

17 

tt         «    01(J          <t                   «                   «                       tt 

23 

26 

From  siphons  to  the  clear-water  basin,  Rothenburgsort, 

25 

23 

From  clear-water  basin,                                    " 

31 

24 

From  pumping-well, 

28 

40 

From  tap  in  the  Hygienic  Institute,  Hamburg, 

97 

85 

From  tap  at  No.  25  Gunther  Street,          " 

94 

69 

NOTE.  —  Where  no  numbers  of  bacteria  are  given,  the  filters  were  not  in  service  on  the  day 
the  test  was  made. 

*  Chapter  XIII. 

f  The  plan  of  the  works  at   Hamburg  contemplates  twenty-two  filters,  of  which   Filters 
Nos.  9,  10,  13,  and  14  are  to  be  constructed. 


FILTRATION  OF   WATER  SUPPLIES.  153 

The  average  for  the  10  filters  in  service  f)ec.  23,  1893,  was 
20  bacteria  per  cubic  centimeter,  while  for  the  11  filters  in  ser- 
vice Jan.  17,  1894,  the  average  was  22  bacteria  per  cubic  centi- 
meter in  the  filtered  water,  a  reduction  of  98.8  to  98.9  per  cent  of 
the  bacteria  in  the  river  water. 

The  increase  in  numbers  from  the  filters  to  the  taps  at  the 
Institute  of  Hygiene,  and  on  Gunther  Street  in  the  city,  is  not 
in  accord  with  the  experience  at  Lawrence,  Mass.,*  where  the 
numbers  of  bacteria  are  generally  found  to  be  less  as  the  water 
passes  from  the  clear-well  of  the  filter  to  the  service  taps  in  the 
city. 

LAWRENCE,    MASS.      CITY    FILTER. 

BACTERIA  PER  C.  C.     AVERAGES  FOR  1895. 

OUTLET  OF 

MERRIMAC  EFFLUENT  DISTRIBUTING  TAP  AT  TAP  AT 

RIVER  WATER.        FROM  FILTER.  RESERVOIR.  CITY  HALL.  EXPERIMENT  STATION. 

10,666  122  122  84  77 

From  daily  bacterial  examinations  for  the  six  months  ending 
April  30,  1896,  the  following  averages  are  given  :  f  — 

LAWRENCE,    MASS.      CITY   FILTER. 

BACTERIA  PER  C.  C.  OF  WATER. 

OUTLET  OF 

MERRIMAC  EFFLUENT  DISTRIBUTING  TAP  AT  TAP  AT 

RIVER  WATER.  FROM  FILTER.  RESERVOIR.  CITY  HALL.         EXPERIMENT  STATION. 

7,533  134  119  86  85 

The  Hamburg  filters  were  started  in  operation  five  months 
before  the  Lawrence  filter,  and  the  influence  of  the  better  water 
on  the  bacteria  in  the  street  mains  should  be  no  less  in  the  former 
than  in  the  latter  city.  Such  information  as  has  come  to  the 
author  on  this  subject  indicates  that  within  a  period  of  three 
months  or  less,  the  regimen  of  the  purified  water  is  fully  estab- 
lished in  the  street  mains  and  service  pipes,  and  neglecting  the 
influence  of  a  possible  higher  temperature  of  the  water  in  the  ser- 
vice pipes  than  in  the  clear-well  of  the  filters,  the  former  should 
show  fewer  bacteria  than  the  freshly  filtered  water.  The  Law- 

*    Twenty-seventh  Annual  Report  Massachusetts  State  Board  of  Health,  p.  573,  et  seq. 
t  Ibid.,  p.  581. 


154  THE   PURIFICATION  OF   WATER. 

rence  experience  is  in  accord  with  this  theory,  and  the  author's 
investigations  along  this  line  generally  indicate  that  with  filtered 
water  in  pipes,  and  therefore  not  exposed  to  light  and  air,  nor  to 
increased  temperature,  the  bacteria  diminish  in  numbers  per  cubic 
centimeter  after  the  water  leaves  the  filters. 


DOUBLE    FILTRATION. 

During  the  investigation  by  the  Royal  Commission  on  Metro- 
politan Water  Supply,  it  was  suggested  by  Dr.  E.  Frankland,* 
that  the  quality  of  the  London  river  waters  might  be  improved  by 
a  second  or  double  filtration.  At  first  sight  this  proposition  looks 
very  favorable,  and  if  the  operation  of  a  sand  filter  was  the  same 
as  that  of  a  fine  strainer  it  would  doubtless  improve  the  quality 
of  the  water  by  passing  it  successively  through  two  or  more  filters 
of  diminishing  sizes  of  sand ;  but  considering  the  action  of  a  filter 
in  the  removal  of  bacteria  from  water  as  a  biological  process,  then 
double  filtration  might  yield  a  poorer  filtrate  than  single  filtration. 

The  formation  of  the  gelatinous  film  on  the  surface  of  the 
sand,  and  the  closing  of  the  pores,  is  hastened  by,  and,  in  fact,  is 
partly  due  to  the  deposition  of  the  suspended  organic  matter  in 
the  water.  In  the  process  of  double  filtration  this  organic  matter 
would  be  almost  wholly  arrested  upon  the  first  filter,  leaving  a 
small  amount  of  material  in  the  water  from  which  to  form  the 
film  on  the  second  filter,  and  the  partially  purified  water  would  in 
all  probability  pass  through  the  latter  with  little  improvement  in 
quality.  A  preliminary  filtration  through  a  thin  bed  of  coarse 
sand,  which  would  intercept  the  larger  and  heavier  suspended 
matters,  might  be  of  advantage  in  some  instances,  but  as  a  rule, 
double  filtration  cannot  be  regarded  as  the  proper  remedy  for 
unsatisfactory  single  filtration. 

The  biologic  work  of  a  plain  sand  filter  has  been  so  well 
established  that  any  proposition  which  inferentially  rejects  this 
theory  of  action  should  be  very  carefully  considered  before  it  is 
adopted  in  practice. 

The  film  at  the  surface  of  the  sand-bed  consists  partly  of  the 

*  Minutes  of  Evidence,  p.  482,  et  seq. 


FILTRATION  OF   WATER  SUPPLIES.  155 

intercepted  suspended  matters,  and  partly  of  the  products  of  bac- 
terial action  on  the  suspended  organic  matter  in  the  water,  and 
this  film  in  due  time  becomes  in  itself  a  very  fine  strainer,  retain- 
ing thus  at  the  top  of  the  sand-bed  the  food  for  support  of  bacte- 
rial life ;  and  double  filtration,  to  be  successful,  must  contemplate 
a  free  passage  of  much  of  the  food  material  and  bacteria  through 
the  sand-bed  of  the  first  filter,  to  form  the  film  on  the  sand  of  the 
second  filter. 

The  author  would  gauge  the  performance  of  a  filter  by  its  prac- 
tical results,  and  practical  results  are  to  be  found  in  the  influence 
of  the  water  upon  the  typhoid  fever  rates  of  the  city  supplied  from 
such  filter.  It  matters  not  how  much  the  bacteria  are  reduced  in 
percentage  of  the  applied  water,  or  how  far  nitrogenous  organic  mat- 
ter has  been  advanced  towards  nitrous  and  nitric  acids,  if  the  ty- 
phoid fever  rates  have  not  been  lowered.  But  with  a  reduction  of 
the  bacteria,  and  conversion  of  organic  matter  into  harmless  com- 
pounds, there  ought  to  be  a  reduction  in  the  typhoid  fever  rates. 
That  it  should  be  so  none  will  deny.  But  since  the  reduction  of 
the  typhoid  fever  rates  is  what  we  are  aiming  at,  why  not  make 
this  the  measure  of  efficiency,  and  let  the  standard  of  operation  of 
filters  be  based  upon  the  percentage  reduction  of  case  and  death 
rates,  —  or  better  still,  let  the  contracts  and  performance  be  based 
upon  a  given  death  rate  from  typhoid  fever,  which  shall  follow  the 
use  of  such  filtered  water? 

This  is  the  practical  result  which  cities  desire,  and  for  which, 
when  men  are  found  with  sufficient  confidence,  combined  with 
knowledge,  to  pledge  such  results,  the  author  believes  they  are 
willing  to  pay.  It  is  all  very  well  to  point  to  a  reduction  of  99.9 
per  cent  of  the  bacterial  contents,  and  to  the  great  chemical  changes 
which  have  taken  place  in  the  water  while  passing  through  the 
filter  ;  but  these  are  only  steps  in  the  journey,  the  end  being  the 
reduction  of  the  typhoid  rates. 

If  the  register  of  vital  statistics  shows  a  reduction  by  the  use 
of  filtered  water  from  40  to  8  per  100,000  of  population,  or  a  per- 
centage reduction  of  80  in  the  typhoid  rates,  what  need  we  care 
about  the  degree  of  bacterial  and  chemical  changes  ?  Here  we  have 


156  THE  PURIFICATION  OF   WATER. 

something  tangible,  something  that  the  people,  as  well  as  the  bacte- 
riologist and  chemist,  can  grasp,  and  appreciate  at  its  full  value. 

INFLUENCE    OF    STORAGE    ON    FILTERED    WATERS. 

With  reference  to  the  time  which  water  may  be  carried  in  sto- 
rage after  filtration,  this  will  depend  to  some  extent  upon  the  origi- 
nal source  of  the  water.  Surface  waters  always  exposed  to  light 
will  be  less  affected  by  the  growths  of  flora  and  fauna  than  ground 
waters.  No  water,  whether  pure  or  purified,  will  be  so  destitute  of 
organic  matter  and  bacteria  as  to  no  longer  furnish  the  material 
for  further  algous  and  bacterial  development.  But  if,  among  the 
forms  of  bacterial  life  in  stored  waters,  there  are  none  of  the  patho- 
genic species,  and  in  the  organic  matter  in  process  of  destruction 
there  are  no  ptomains,  no  objection  from  the  standpoint  of  hy- 
giene can  possibly  be  raised  to  the  processes  which  may  be  going 
on  in  stored  water. 

The  experience  abroad  universally  favors  the  covering  of  sto- 
rage or  service  reservoirs  for  filtered  water.  Whether  this  precau- 
tion is  absolutely  necessary  in  all  cases  has  not  been  shown  as  the 
result  of  carefully  conducted  investigations,  and  it  is  possible  that 
certain  waters  can  be  filtered  and  carried  without  injury  to  quality 
in  open  reservoirs  for  many  days.  Iron,  lime,  sulphur,  and  other 
salts  in  solution  in  waters,  favor  the  growth  of  some  species  of 
vegetable  life ;  and  the  nature  of  the  dissolved  mineral  substances 
in  water  doubtless  has  a  strong  influence  on  its  quality,  if  carried 
in  storage  after  filtration. 

It  is  stated  in  connection  with  the  Anderson  Iron  Purifiers  at 
Paris,  that  the  water  from  these  is  carried  for  nearly  three  weeks 
in  covered  reservoirs  without  change  in  bacterial  contents,  color, 
taste,  or  odor.  Upon  the  contrary,  the  water  from  the  Lawrence, 
Mass.,  filter  is  pumped  to  an  open  distributing  reservoir ;  and  the 
only  cause  of  complaint  which  the  author  has  noticed  in  the 
Annual  Reports  since  the  filter  was  started  in  service  has  been 
the  formation  of  ice  on  the  reservoir  and  filter.  The  reservoir, 
when  filled  to  a  depth  of  25  feet,  has  a  water  surface  694  by  375 
feet,  contains  40,000,000  gallons,  and  represents  about  13  days' 


FILTRATION  OF   WATER   SUPP 


157 

0 '  • 
storage.      It  consists  of  two  equal  compartments,  and  the  water  is 

delivered  to  either  or  both  divisions  of  the  reservoir  at  will. 

The  experience  at  Quincy,  111.,  with  stored  filtered  water,  is 
very  different  from  that  at  Lawrence,  Mass.  At  the  former  place, 
since  filtration  has  been  practiced,  during  the  summer  months 
"there  is  a  vegetable  growth  of  a  mossy  character  which  some 
seasons  imparts  a  fishy  or  woody  taste  to  the  water  and  other 
seasons  does  not."  At  Quincy  mechanical  filtration  with  alum 
is  resorted  to,  while  Lawrence  depends  upon  plain  sand  filtration. 
(The  author  is  not  aware  of  any  investigations  upon  the  influence 
of  undecomposed  alum  in  water  on  certain  species  of  plant  life,  and 
it  is  possible  when  these  are  made,  they  may  show  that  plants 
having  a  strong  affinity  for  potash  or  sulphur,  will  flourish  in  water 
purified  with  alum.)  The  reservoir  at  Quincy  has  an  available 
water  depth  of  22  feet,  a  water  surface  of  350  by  250  feet,  and 
contains  18,000,000  gallons.  The  average  daily  consumption  dur- 
ing 1896  was  1,261,900  gallons,  and  the  reservoir  contains  at  the 
present  time  about  14  days'  supply. 

By  Act  of  Parliament,  1855,  the  water  companies  of  London 
were  required  to  cover  all  distributing  reservoirs  which  received 
filtered  water  within  a  radius  of  five  miles  from  St.  Paul's ;  and 
according  to  the  statistics  of  the  London  works  for  1893,  the 
aggregate  capacity  of  these  reservoirs  represented  about  four- 
fifths  of  the  average  daily  consumption,  or  20  hours'  supply.  At 
Berlin,  Hamburg,  and  other  cities  of  continental  Europe,  which, 
like  London,  use  filtered  waters,  the  distributing  reservoirs  are 
of  small  relative  dimensions,  and  not  intended  for  storage,  but  to 
compensate  for  the  varying  rates  of  consumption  during  the  day. 


158  THE   PURIFICATION  OF    WATER. 


CHAPTER  XI. 

TYPES    OP   SAND    FILTERS. 

SAND  FILTERS  may  be  classed  as  of  four  types  :  — 

1.  The  so-called   continuous   filters  of  European  practice,   as 

designed   by  Mr.  James   Simpson  of   the  Chelsea   and 
Lambeth  Water- Works. 

2.  The  intermittent  filter,  as  designed  by  Mr.  Hiram  F.  Mills, 

C.  E.,  for  the  water-works  of  Lawrence,  Mass. 

3.  Natural  filtration  into  collecting  galleries,  as  illustrated  in 

the  water-works  of  Lyons  and  Angers,  France,  and  in 
some  cities  of  this  country. 

4.  Mechanical  filters,  in  which  the  sand-bed  is  restored  to  its 

normal  condition  by  washing,  without  removal  from  the 
filter. 

In  situations  where  artificial  filters  are  to  be  covered,  there  will 
be  a  saving  in  space  by  constructing  the  walls  of  masonry  backed 
by  puddle,  as  shown  by  Fig.  8  ;  but  with  open  filters,  such  as 
are  used  in  London  and  Hamburg,  certain  advantages  are  to  be 
had  from  the  sloped  walls,  as  shown  by  Fig.  13  (Chapter  XIIL). 
Where  filters  are  liable  to  be  covered  with  an  ice-cake,  and  the 
method  of  sand  cleaning  under  the  ice  as  practiced  at  Hamburg  is 
adopted  (Fig.  26),  then  a  sloped  inside  wall  is  absolutely  essential 
to  the  proper  operation  of  this  apparatus.  The  continuous  filter  is 
usually  rectangular  in  plan  ;  but  this  is  varied  to  suit  the  location, 
some  of  the  London  filters  being  circular.  So  far  as  form  affects 
filtration,  the  beds  may  take  any  of  the  regular  shapes  in  plan  ;  but 
for  convenience  of  scraping  and  removing  the  sand,  the  rectangular 
form  is  to  be  preferred.  Regulating  devices  to  limit  the  head  on 
a  filter  are  regarded  now  as  essential  features  of  such  works,  in 
order  to  remove  as  far  as  possible  from  the  attendants  the  power 


TYPES  OF  SAND  FILTERS. 


159 


to  seriously  interfere  with  the  regularity  of  operation  of  a  filter. 
These  regulating  devices  generally  consist  of  floats  which  rise  and 


Section  of  Gathering  Drain. 

Fig.  8.    St.  Louis  Water-Works.    Details  of  Filters. 

fall  with  the  water  in  the  inlet  and  outlet  wells,  actuating  large 
balanced  valves  which  are  automatically  raised  and  lowered  to 
admit  more  or  less  water  through  the  passages. 


160  THE   PURIFICATION  OF   WATER. 

In  cases  where  automatic  regulators  are  lacking,  sliding  weirs 
and  valves  or  gates,  adjustable  by  hand,  under  intelligent  super- 
vision, will  accomplish  the  same  results.  In  order  that  the  effective 
head  on  the  filter  and  rate  of  nitration  might  be  conveniently  reg- 
ulated, Mr.  Kirkwood  proposed  the  device  shown  by  Fig.  8,  con- 
sisting of  a  weir  which  could  be  raised  or  lowered  in  guides  by 
means  of  the  winch  shown  at  the  ground  level.  With  this  device 
the  draught  upon  the  clear- well,  and  the  raising  and  lowering  of 
the  water-level  therein,  can  have  no  effect  upon  the  rate  of  delivery 
of  the  filter. 

The  continuous  sand  filter  of  European  practice  consists  of  a 
shallow  reservoir  with  inclined  or  sloping  sides  when  made  with 
earthen  walls,  or  with  vertical  sides  if  made  of  masonry.*  The 
surface  area  of  these  reservoirs  ranges  from  an  acre  or  less  to  as 
much  as  two  acres.  The  depth  of  the  reservoir  is  10  or  12  feet, 
according  to  the  local  character  of  the  water,  the  materials  avail- 
able for  the  filter-beds,  and  the  views  of  the  designer. 

The  two  general  methods  of  construction  of  the  basin  part  of 
plain  sand  filters  is  clearly  shown  by  Fig.  8,  which  is  a  section 
of  the  filter  proposed  by  Mr.  Kirkwood  for  the  city  of  St.  Louis 
(1866),  and  by  Fig.  15  (Chapter  XIII.),  which  is  a  plan  and  sec- 
tion of  the  filters  of  Hamburg.  When  the  walls  are  vertical,  as 
shown  by  Mr.  Kirkwood's  plan,  these  must  be  of  masonry,  backed 
with  puddle  or  an  impervious  clay.  When  made  with  slopes  inside, 
the  slope  should  be  of  water-tight  materials,  or  puddled,  and  faced 
with  a  pavement  or  lining  of  concrete,  asphalt,  brick,  or  stone  set 
in  mortar.  Should  ice  form  on  the  water  in  the  filter,  the  thrust 
of  the  cake  is  less  liable  to  injure  the  sloped  sides  than  the  vertical 
walls,  while  the  cost  of  construction  favors  the  basin  with  sloped 
walls. 

In  the  bottom  of  this  reservoir  is  placed  a  system  of  lateral 
parallel  drains,  which  collect  the  water  from  all  parts  of  the  filter, 
and  conduct  it  to  one  or  more  main  central  drains,  by  which  it  is 
removed  from  the  filter  to  the  clear-well,  and  from  this  it  is  pumped 
to  distributing  reservoirs,  or  direct  into  the  distributing  mains. 

Over  the  drains  in  the  bottom  of  the  filter  is  laid  a  course  of 

*  "  Hygiene  of  Water,"  by  the  author,  Dietetic  and  Hygienic  Gazette,  1896,  p.  599. 


TYPES   OF  SAND   FILTERS.  161 

• 

broken  stone  or  large  gravel  about  12  or  15  inches  thick  ;  over 
this  a  layer  of  small  gravel  6  inches  thick  ;  over  this  a  layer  of 
coarse  sand  6  to  12  inches  thick;  and  on  top  of  the  coarse  sand  is 
placed  a  layer  of  graded  sand  from  24  to  36  inches  thick.  This 
upper  layer  of  sand  is  the  real  filtering  material,  the  layers  of 
sand  and  gravel  below  simply  being  beds  for  the  support  of  this 
finer  bed  of  graded  sand  at  the  top  of  the  filter. 

The  capacity  of  a  filter  is  stated  as  the  average  number  of 
gallons  which  it  will  deliver  per  acre  per  day  during  the  time  it  is 
in  service.  When  the  filter  is  new  and  the  sand  surface  clean,  the 
rate  of  delivery  will  be  quite  up  to  the  average  rate,  even  with  a 
few  inches  difference  of  water  level  over  the  sand  and  in  the  efflu- 
ent chamber  ;  but  as  the  sand  becomes  clogged  with  the  suspended 
matters  in  the  water,  and  by  the  products  of  bacterial  action  upon 
the  organic  matter,  the  effective  head  of  water  on  the  sand-bed 
must  be  gradually  increased,  to  filter  the  water  at  or  near  the 
standard  rate,  until  in  due  time  the  limiting  head  is  reached,  and 
the  rate  of  delivery  of  the  filter  diminishes  until  it  is  no  longer 
profitable  to  operate  it,  when  the  water  is  shut  off  from  it  altogether, 
and  the  filter  taken  temporarily  out  of  service. 

The  upper  layer  of  graded  sand  is  then  carefully  scraped  for  a 
depth  of  about  one-half  inch,  the  dirty  sand  removed  and  washed 
by  mechanical  apparatus  devised  for  the  purpose,  and  stored  in  the 
sand-house  preparatory  to  putting  it  back  on  the  filter  whenever 
the  successive  scrapings  have  reduced  the  thickness  of  the  upper 
sand-bed  to  15  or  20  inches.  The  thickness  of  the  upper  layer  of 
sand  is  seldom  reduced  to  less  than  15  inches,  and  the  lower  layers 
of  sand  and  gravel  are  not  disturbed  or  renewed  at  all  unless  some 
radical  overhauling  of  a  filter  is  shown  to  be  necessary  by  the  bac- 
terial analyses  of  the  water. 

During  the  time  of  service  of  such  a  filter,  it  is  acting  continu- 
ously without  interruption,  day  and  night ;  and  the  rate  of  delivery 
is  maintained  either  by  manual  labor  or  automatic  regulating  de- 
vices as  near  to  an  established  standard  as  possible. 

The  rate  of  delivery  will  depend  (1)  upon  the  grade  of  sand 
in  the  upper  layer,  (2)  the  effective  head  of  water  on  the  sand-bed, 
and  (3)  the  condition  of  the  water  when  it  comes  to  the  filter. 


162  THE  PURIFICATION  OF  'WATER. 

Neglecting  the  grade  of  sand  and  head,  which  are  subject  to  con- 
trol, it  can  generally  be  said  that  the  rate  of  operation  will  depend 
upon  the  condition  of  the  water.  Therefore,  when  filters  are 
operated  in  connection  with  subsiding  reservoirs,  i.e.,  where  the 
work  of  purification  is  a  process  of  filtration  combined  with  sedi- 
mentation, the  larger  the  amount  of  work  done  in  the  subsiding 
reservoirs,  the  finer  may  be  the  grade  of  sand  used,  and  the  higher 
the  rates  of  delivery  of  the  filters  per  unit  of  sand  surface.  The 
smaller  size  of  sand-grain  within  certain  limits  will  insure  an  im- 
proved quality  of  filtrate,  and  the  higher  rate  of  delivery  will  effect 
a  reduced  cost  of  treatment  per  million  gallons  of  water. 

Grading  of  Filter  Materials.  —  In  order  that  a  filter  shall  give 
satisfactory  results,  both  in  rate  of  operation  and  quality  of  filtrate, 
it  is  necessary  that  the  filtering  materials,  especially  the  bed  of  sand, 
shall  be  selected  with  regard  to  the  size  of  its  grains,  and  the  rela- 
tion to  each  other  by  weight  of  these  several  sizes  in  a  bed  of  mixed 
sand.  In  practice,  wherever  much  experience  has  been  had  with 
sand  filters,  the  materials  are  classified  as  boulders  (or  broken 
stone),  gravel,  and  sand,  the  gravel  being  used  frequently  of  two 
sizes,  and  denominated  as  coarse  and  fine  gravel,  and  the  sand  of 
two  general  grades,  a  coarser  grade  above  the  small  gravel,  and 
the  finer  filtering-sand  at  the  top  of  the  filter-bed. 

Filtering  materials,  as  used  at  the  experiment  station  of  the 
Massachusetts  State  Board  of  Health,  are  examined  as  to  "  size  " 
and  "  uniformity  "  of  size  of  grains  or  particles,  and  graded  to  suit 
the  particular  work  to  which  they  are  applied.  Chemical  and  bac- 
terial analyses  are  also  made  of  the  matter  attached  to  the  sand 
grains,  which  it  appears,  even  after  repeated  washings,  is  not 
entirely  removed.* 

The  larger  materials  can  readily  be  graded  by  hand  picking ; 
sands  not  less  than  0.10  mm.  mean  diameter  are  separated  and 
graded  into  commercial  sizes  by  a  series  of  sieves  of  brass  wire,  set 
in  metal  rims  and  shaken  in  a  machine,  for  a  time  sufficient  to 
secure  the  passage  through  the  sieves  of  all  but  the  particles  larger 
than  the  mesh  of  the  wire  cloth,  while  particles  of  sand  smaller 
than  0.10  mm.  in  any  diameter  are  graded  by  water  elutriation. 

*  Miiggel  Lake  Water  Supply,  by  Henry  Gill,  p.  11. 


TYPES  OF  SAND  FILTERS.  163 

The  method  of  separation  of  a  mixed  sand* into  its  several  sizes 
by  means  of  sieves  is  obvious,  and  requires  no  explanation.  Water 
elutriation  of  sand  consists  in  adding  to  a  volume  of  distilled 
water,  measured  in  a  beaker,  a  definite  weight  of  clean,  dry  sand  ; 
and  after  a  thorough  mixing  of  the  sand  and  water  by  means  of  a 
strong  current  of  air  passed  through  a  glass  tube,  a  given  time  is 
allowed  for  the  precipitation  by  gravity  of  the  sand  to  the  bottom 
of  the  beaker.  It  is  well  known  that  after  the  mixing  of  solids  in 
a  fluid,  the  larger  and  heavier  particles  settle  first,  and  an  experi- 
ment will  demonstrate  that  all  grains  of  sand  of  not  less  than  a 
given  diameter  will  be  precipitated  within  a  given  time.  By  allow- 
ing more  time,  grains  of  smaller  size  and  weight  will  settle  out  of 
the  water ;  and  by  allowing  sufficient  time,  all  the  grains,  however 
small  they  may  be,  will  have  been  precipitated  to  the  bottom  of 
the  beaker,  and  the  distilled  water  above  will  be  free  from  all  sus- 
pended sand. 

Adopting  the  results  of  sand  measurement  by  the  Massachu- 
setts State  Board  of  Health  (with  230  cubic  centimeters  of  water 
and  5  grams  of  sand),  after  a  thorough  mixing  of  the  sand  in  the 
water,  all  grains  which  are  precipitated  to  the  bottom  of  the  beaker 
within  15  seconds  are  considered  as  of  not  less  than  0.08  mm.  diam- 
eter. Similarly,  all  grains,  which  upon  mixing  and  allowing  one 
minute  for  subsidence  are  collected  at  the  bottom  of  the  beaker, 
are  regarded  as  of  not  less  than  0.04  mm.  diameter,  and  all  grains 
which  remain  suspended  in  the  water  at  the  end  of  one  minute  are 
regarded  as  'of  less  than  0.04  mm.  diameter.  The  weight  of  the 
smallest  particles  in  a  mixture  of  sand,  the  largest  grains  of  which 
are  less  than  0.10  mm.  diameter,  is  obtained  by  deducting  from 
the  whole  mass  (5  grams)  the  added  weight  of  the  grains  larger 
than  0.08  mm.  diameter,  and  the  grains  less  than  0.08  mm.  but 
larger  than  0.04  mm.  diameter.  The  difference  is  held  to  be  the 
weight  of  the  grains  less  in  diameter  than  0.04  mm. ;  i.e.,  sizes  from 
0.10  mm.  down  to  0.08  mm.,  and  from  0.08  mm.  to  0.04  mm.,  are 
determined  by  water  elutriation,  while  smaller  sizes  are  held  to 
be  the  difference  between  the  whole  weight  and  the  sum  of  the 
weights  of  the  two  larger  sizes. 

In  stating  the  dimensions  used  for  comparison  of  sand-grains 


164  THE   PURIFICATION  OF   WATER. 

in  a  mass  of  sand  constituting  a  filter-bed,  two  terms  have  been 
proposed  by  the  Massachusetts  State  Board  of  Health*  which  are 
convenient  for  general  use. 

Effective  Size  of  Sand-Grain.  —  This  is  that  diameter  of  grain 
in  a  mass  of  sand  of  which  10  per  cent  of  the  mass  by  weight  is 
smaller,  and  90  per  cent  is  larger  in  size.  Thus,  if  upon  physical 
analysis  of  a  body  of  sand  by  sieves  or  any  convenient  method,  it 
is  found  that  the  largest  diameter  for  the  10  per  cent  by  weight  of 
the  smaller  grains  is  0.50  mm.,  and  90  per  cent  is  of  diameter 
larger  than  0.50  mm.,  then  0.50  mm.  would  be  regarded  as  the 
"effective  size."  Or,  assuming  the  mass  of  sand  to  be  regularly 
graded  from  the  finest  to  the  coarsest  particles,  then  the  "  effec- 
tive size"  will  be  that  size  of  which  10  per  cent  of  the  whole  mass 
by  weight  is  smaller  in  diameter. 

Uniformity  Coefficient.  —  This  is  the  ratio  of  the  diameter  of 
the  sand-grain  of  which  by  weight  60  per  cent  is  finer  than  itself, 
to  the  diameter  or  size  of  which  10  per  cent  is  finer  than  itself. 
If  by  weight  60  per  cent  of  a  sample  of  sand  is  less  than  0.50  mm., 
and  10  per  cent  is  less  than  0.25  mm.,  the  "  uniformity  coefficient  " 
is  =g  =  2 ;  or  the  diameter  of  grains  of  which  60  per  cent  is  finer 
than  itself,  divided  by  the  "effective  size,"  gives  the  " uniformity 
coefficient." 

The  lower  the  "uniformity  coefficient,"  i.e.,  the  more  regular 
in  size  are  the  grains  of  sand  in  any  mass,  the  larger  will  be 
the  water  space  or  voids.  With  a  high  "  uniformity  coefficient," 
i.e.,  with  great  irregularity  of  size  in  the  sand-grains,  the  smaller 
will  be  the  water  space  or  voids. 

The  influence  on  the  bacterial  efficiency  of  filters  of  the  "  effec- 
tive size  "  of  sand-grains,  with  widely  different  rates  of  filtration, 
is  shown  by  the  table  on  the  following  page. 

The  term  "  effective  size  "  must  not  be  confounded  with  the 
average  size  of  sand-grain  in  a  sample.  The  average  size  in  a 
mass  of  mixed  sand  being  always  larger  in  diameter  than  the 
"  effective  size."  The  results  obtained  at  Lawrence  indicate  that 
the  finer  10  per  cent  of  sand  has  as  much  influence  on  filtration 
as  the  coarser  90  per  cent. 

*   Twenty-fourth  Annual  Report  Massachusetts  State  Board  of  Health,  p.  541. 


TYPES   OF  SAND   FILTERS. 


165 


EXPERIMENTAL   FILTERS,   LAWRENCE,   MASS.,   1895. 


RATE  OF 

EFFECTIVE  SIZE 

TYPE  OF  FILTER. 

FILTRATION. 
GALLONS  PER  ACRE 

OF 

SAND-GRAINS. 

UNIFORMITY 
COEFFICIENT. 

BACTERIAL 
EFFICIENCY. 

PER  DAY. 

MILLIMETERS. 

Continuous, 

1,980,000 

0.14 

2.2 

99.49 

« 

3,576,000 

0.23 

2.3 

99.73 

«( 

6,780,000 

0.29 

2.7 

99.37 

(i 

4,280,000 

0.38 

3.5 

99.51 

(C 

4,680,000 

0.48 

2.4 

99.45 

Intermittent, 

1,960,000 

0.14 

2.2 

99.75 

(t 

3,096,000 

0.23 

2.3 

99.16 

tt 

6,600,000 

0.29 

2.4 

99.38 

« 

4,500,000 

0.48 

2.4 

99.57 

Sterilization  of  Filter  Sand.  —  The  sterilization  of  the  sand-bed 
of  the  mechanical  filter  used  in  the  Providence,  R.I.,  tests*  was 
shown  by  Mr.  Weston  to  have  no  influence  upon  the  bacterial 
efficiency  of  the  filter ;  boiling  of  the  sand  in  water  for  "  one  hour 
and  fifty  minutes  "  did  not  improve  its  capacity  to  restrain  the 
passage  of  bacteria.  Piefke,  of  the  Berlin  Water- Works,f  previ- 
ously had  experimented  with  sterilized  sand  in  a  small  filter,  with 
the  result  that  "more  organisms  were  found  in  the  filtrate  than 
in  the  unfiltered  water." 

The  same  result  has  repeatedly  been  shown  during  the  experi- 
ments of  the  Massachusetts  State  Board  of  Health  at  Lawrence.J 
"  Heating  the  sand  and  pouring  the  boiling  water  through  it 
caused  100  times  as  many  bacteria  to  pass  through  it  with 
sewage  for  three  months  as  passed  through  a  similar  filter  whose 
sand  and  first  water  had  not  been  heated." 

Experience  has  amply  demonstrated  that  the  proper  treatment 
of  sand  for  use  in  water  filters  is  a  thorough  washing,  finally,  with 
filtered  water,  until  all  detachable  matter  is  removed  from  the 
grains,  and  in  this  condition  the  sand  placed  in  the  filter.  The 
improved  chemical  and  bacterial  results  of  washed  over  sterilized 
sand  suggests  that  the  bacteria,  which  find  a  suitable  nidus  in  a 


*  Report  on  Results  Obtained  -with  Experimental  Filters,  Providence,  R.I.,  p.  119. 

t  1887. 

\  H.  F.  Mills,  Transactions  American  Society  Civil  Engineers,  vol.  xxx.,  p.  359. 


166  THE   PURIFICATION  OF   WATER. 

sand-bed  after  the  sand  has  been  washed,  are  useful  in  the  destruc- 
tion of  organic  matter  and  of  some  species  of  water  bacteria. 


LAWRENCE,   MASS.,   INTERMITTENT    SAND    FILTER. 

This  filter  is  the  outgrowth  of  two  forces  :  (1)  the  abnormally 
high  typhoid  fever  rates  of  the  city  of  Lawrence ;  and  (2)  the 
labors  of  the  State  Board  of  Health  along  the  line  of  water  purifi- 
cation. It  consists  of  a  single  filter  with  a  sand  area  of  2.50  acres  ; 
and  instead  of  a  horizontal  surface,  like  the  European  filters,  the 
bed  of  sand  is  furrowed  or  channeled  from  side  to  side  to  provide 
a  uniform  thickness  of  sand  through  which  the  water  from  all 
points  is  compelled  to  percolate  to  the  collecting  drains  at  the 
bottom  of  the  filter. 

The  mean  elevation  of  the  surface  of  the  sand-bed  is  2  feet 
below  low  water  in  the  Merrimac  River,  and  the  filter  is  flooded  for 
this  depth  from  the  river.  The  tank  in  which  the  filter  is  con- 
structed consists  of  an  excavation  in  the  bank  of  the  river,  with  a 
bottom  elevation  averaging  7  feet  below  low-water  mark. 

The  general  dimensions  of  this  filter,  as  given  in  the  Report 
of  the  Massachusetts  State  Board  of  Health  for  1893,  are  as 

follows  :  — 

Width  of  filter,  150  feet. 

Length  of  filter,  750    " 

Effective  area  of  sand  surface,  2.50  acres. 

Depth  of  filtering-sand,  5.00  feet. 

Effective  size  of  sand,  0.25  mm. 

The  underdrains  were  placed  30  feet  apart.  On  the  line  of 
each  drain  the  excavation  is  carried  down  to  elevation  8  feet  below 
low-water  mark  in  the  river,  for  a  width  of  5  feet ;  and  the  crests 
of  the  ridges  midway  between  the  underdrains  are  at  elevation 
6  feet  below  low-water  mark,  and  5  feet  wide.  From  the  crest 
down  to  the  channel  for  the  underdrains,  the  bottom  is  sloped  at 
the  rate  of  5  feet  horizontal  to  1  foot  vertical. 

Over  the  ridges  the  depth  of  filtering-sand  was  made  3  feet 
for  a  width  of  5  feet,  and  over  the  line  of  underdrains  the  depth 
of  sand  was  made  6  feet  for  a  width  of  5  feet,  the  surface 


TYPES   OF  SAND   FILTERS. 


167 


slope  of  the  sand  from  the  ridges  to 
the  crests  being  10  feet  horizontal  to 
1  foot  vertical. 

The  section  given  in  Fig.  9  indi- 
cates the  manner  in  which  the  bottom 
of  filter  and  surface  of  sand-bed  were 
furrowed. 

From  the  description  in  the  report, 
it  appears  that  each  furrow  or  channel 
with  its  underdrain  and  superimposed 
filtering  material  is  complete  in  itself, 
the  underdrain  terminating  in  a  10-inch 
pipe  which  passes  through  the  masonry 
wall  of  an  old  filter  gallery  (lying  paral- 
lel to  the  new  filter).  This  filter  gal- 
lery became,  upon  completion  of  the 
new  intermittent  filter,  the  clear-water 
reservoir  from  which  the  pumps  take 
water.  Assuming  each  30  feet,  then,  a 
complete  section  of  the  filter,  there  are 
25  such  sections  in  the  whole  bed. 

The  underdrains  consist  partly  of 
broken  stone,  and  partly  of  glazed 
sewer  pipe  from  4  to  10  inches  diam- 
eter, the  larger  pipe  going  through  the 
wall  of  the  former  filter  gallery.  Con- 
sidering an  underdrain  150  feet  long 
(width  of  filter),  the  broken  stone  and 
pipe  are  placed  as  follows  :  — 

Broken  stone,  90  feet. 

Four-inch  sewer  pipe,  6     " 

Six-inch  sewer  pipe,  50     " 

Eight-inch  sewer  pipe,  4    « 

Total,  150  feet. 

The  general  slope  or  grade  of  the 
drain  is  given  as  1  foot  fall  in  100  feet 
of  length. 


:-*-»- 


— '-* 


',9 


Fig.  9. 

Longitudinal  Section  of  Lawrence 
(Mass.)  Filter. 


168  THE   PURIFICATION  OF   WATER. 

The  water  is  brought  from  the  river  through  a  24-inch  iron 
pipe,  which  discharges  into  an  open  conduit,  at  one  side  of  the 
filter,  from  which  channels  of  concrete  are  extended  to  within  32 
feet  of  the  farther  side  of  the  sand-bed.  This  conduit,  together 
with  the  lateral  channels,  are  intended  to  secure  a  uniform  distri- 
bution of  the  water  over  the  surface  of  the  filter  bed. 

In  the  construction  of  this  filter,  the  bottom  (as  is  customary 
to  prevent  entrance  and  mixing  of  ground  water  with  the  filtered 
water)  was  not  made  water-tight,  neither  was  the  filter  covered  as 
the  climate  seems  to  require,  for  the  reason  as  given  by  Mr.  Hazen.* 

"It  was  no  easy  matter  to  secure  the  consent  of  the  city  government  to 
the  expenditure  of  even  the  sum  used ;  there  was  much  skepticism  as  to  the 
process  of  filtration  in  general,  and  it  was  said  that  mechanical  niters  could  be 
put  in  for  about  the  same  cost.  Insisting  upon  the  more  complete  and  expen- 
sive form  might  have  resulted  either  in  an  indefinite  postponement  of  action, 
or  in  the  adoption  of  an  inferior  and  entirely  inadequate  process.  Still,  I  feel 
strongly  that  in  the  end  the  greater  expense  would  have  proved  an  excellent 
investment  in  securing  softer  water,  and  in  the  greater  facility  and  security  of 
operating  the  filter  in  winter." 

The  filter  was  proportioned  for  a  daily  rate  of  2,000,000  gallons 
per  acre,  assuming  that  it  would  be  in  service  for  16  hours  and  at 
rest  for  8  hours,  which  would  make  the  actual  rate  3,000,000  gallons 
per  acre  per  day  while  in  service.  According  to  the  report  for 
1895,  the  rate  was  1,200,000  gallons  per  acre  per  day,  as  an  average 
for  the  year. 

During  the  year  1895,  1,096,000,000  gallons  of  water  were 
passed  through  the  filter,  f  and  the  total  expense  for  maintenance 
was  87,400,  or  $6.75  per  million  gallons  of  water  filtered. 

For  scraping  and  replacing  the  sand, 
For  removing  ice, 

For  washing  1,500  cubic  yards  of  sand, 
Total, 
(Laborers  paid  $2.00  per  day.) 

Omitting  cost  of  removing  ice,  which  would  be  unnecessary  in 
milder  climates,  the  cost  per  million  gallons  of  water  filtered  be- 

*  Filtration  of  Public  Water  Supplies,  New  York,  1895,  p.  98. 

f    Twenty  seventh  Annual  Report  Massachusetts  State  Board  of  Health,  p.  572  et  seq. 


TYPES   OF  SAND   FILTERS.  169 

comes  84.10.  This  being  a  single  filter  on  the  intermittent  plan, 
it  cannot  be  handled  so  advantageously  as  filters  in  series  ;  and  the 
cost  of  operation  per  million  gallons  should  be  greater  than  in  a 
large  plant  embracing  a  series  of  continuous  filters,  in  which  one 
or  more  filters  could  be  taken  out  of  service  from  time  to  time  and 
cleaned  at  convenience. 

The  filter  was  operated  for  1895  at  an  average  rate  of  -WV-  = 
3,000,000  gallons  per  day.  With  an  effective  area  of  sand  surface 
of  2.5  acres,  and  assuming  the  filter  to  have  been  in  service  two- 
thirds  of  the  time,  the  average  rate  of  filtration  per  acre  was 
1,800,000  gallons  per  day.  Estimating  the  population  of  Law- 
rence for  1895  at  50,000,  the  average  daily  consumption  of  water 
amounted  to  60  gallons  per  capita. 

The  following  are  the  average  bacterial  results  for  the  year  :  — 

Bacteria  in  Merrimac  River  water,  5,000-  20,000  colonies  per  c.  c. 

Bacteria  in  effluent  from  filter,  38-       368  colonies  per  c.  c. 

Average  bacterial  reduction,  98.4  per  cent. 

This  filter  is  reported  to  have  cost  §65,000,  or  $26,000  per 
acre  of  effective  filtering  surface. 

In  speaking  of  the  merits  of  plain  sand  filtration,  Mr.  J.  Her- 
bert Shedd,  C.E.,  who  has  given  very  earnest  consideration  to 
the  matter  of  improvement  of  the  Providence,  R.I.,  water  supply, 
says :  —  * 

"  The  construction  of  sand  filters  for  slow  filtration  is  not  an  experiment. 
Their  use  and  value  have  been  demonstrated  in  great  numbers  of  cases  through 
long  periods  of  years.  The  only  reasons  that  I  know  for  departing  from  this 
long-established  practice  is  in  the  effort  to  get  cheaper  first  cost,  or  because 
the  necessary  area  for  their  establishment  is  not  available.  In  the  case  of  the 
city  of  Providence  there  are  about  70  acres  of  suitable  land  near  the  pumping- 
station,  bought  for  this  purpose  more  than  20  years  ago  and  still  available. 
Since  it  has  been  found  that  a  mechanical  filter  is  likely  to  cost  $281,000, 
plans  have  been  made,  levels  taken,  test  pits  dug,  and  estimates  made  for  a 
sand  filter  for  slow  filtration  on  that  land,  with  all  necessary  settling  space, 
supply  conduits  and  screens,  leading  mains,  and  other  appurtenances,  complete 
for  connecting  the  plant  with  our  present  works.  My  estimate  of  the  cost  of 

*  Engineering  Record,  July  22,  1894. 


170 


THE   PURIFICATION  OF   WATER. 


supplying  all  materials  and  doing  this  work  is  about  $208,000  ;  but  whether 
my  estimates  have  any  value  or  not,  the  commissioner  of  public  works  has  in 
his  possession  a  bid  from  responsible  contractors  who  offer  to  do  the  whole 
work  complete  for  $200,000'. 

"  The  cost  of  annual  maintenance  of  the  slow  filtration  plant  will  be,  I 
think,  very  materially  less  than  the  cost  of  maintaining  a  mechanical  plant  of 
the  same  daily  capacity." 

PLAIN    SAND    FILTRATION. 

The  Report  on  the  Providence  experiments  furnishes  some 
interesting  information  upon  plain  sand  filtration  with  a  filter  of 


Fig.  10.     Experimental  Filter,  Providence,  R.  I. 


<t 


the  form  shown  in  Fig.  10.     Two  filters  of  this  style  were  tested 
by  Mr.  Weston,  from  March  27  to  Oct.  5,  1893,  with  occasional 


TYPES  OF  SAND  FILTERS. 


171 


intermissions  for  cleaning  filters  and  changing  sand  ;  and  for  tests 
of  the  influence  of  alum,  on  so-called  natural  filtration.  These 
filters  were  worked  at  rates  of  1,000,000  to  35,000,000  gallons 
per  acre  per  day.  (Fig.  10.) 

Considering  Filter  No.  1,  from  May  15  (before  which  date  the 
operation  was  discontinuous)  to  July  15  (after  which  date  the  con- 
ditions of  operation  were  varied  almost  daily),  the  rates  of  filtra- 
tion varied  from  1,000,000  to  3,500,000  gallons  per  acre  per  day. 
Considering  Filter  No.  2,  from  April  15  (before  which  date  the 
operation  was  quite  irregular,  doubtless  due  to  the  starting  of 
novel  experiments)  to  Sept.  13  (after  which  date  the  operation 
was  discontinuous),  the  rates  of  filtration  varied  from  1,000,000 
to  35,000,000  gallons  per  acre  per  day.  In  the  review  of  the  per- 
formance of  Filter  No.  2,  the  work  is  omitted  from  July  25  to 
July  29  (four  days),  when  alum  was  used.  These  filters  were 
restored  to  service  after  the  sand-beds  became  clogged,  sometimes 
by  washing  the  sand  with  a  reverse  current  of  water,  and  some- 
times by  scraping  the  sand.  The  following  table  will  show  how 
this  occurred  by  dates  for  the  two  filters  :  — 


DATE. 

FILTER  No.  1. 

PERIOD  OF 
SERVICE,  DAYS. 

FILTER  No.  2. 

PERIOD  OF 
SERVICE,  DAYS. 

1893. 

March  27, 

Started, 

.    .    . 

Started, 

.    .    . 

April    21, 

Sand  renewed, 

19 

.  .   . 

.   .    . 

"       29, 

Sand  washed, 

3 

.   .   . 

... 

May      10, 

Sand  renewed, 

4 

.  .  . 

.   .    . 

"       11, 

.  .   . 

Sand  repacked, 

33 

June     14, 

Sand  scraped, 

26 

.   .  . 

.  .  . 

July      14, 

.   .  . 

... 

Sand  washed, 

51 

"       16,* 

Sand  scraped, 

26 

.   .  . 

.  .  . 

"       24, 

.   .   . 

Sand  washed, 

8 

"       27, 

.   .   . 

.   .  . 

Sand  washed, 

3 

August  23,* 

.   .   . 

.   .  . 

Sand  scraped, 

21 

When  the  filters  were  cleaned  by  washing,  the  current  of  water 
was  reversed  as  in  mechanical  filters.  At  times  the  sand-beds 
were  scraped  in  the  usual  way,  taking  off  about  one-half  inch  of 


*  After  these  dates  the  manner  of  operation  was  very  irregular. 


172 


THE   PURIFICATION  OF  WATER. 


sand.      The  size  of    sand   used   in   these   niters    is    given  in  the 
Report  as  follows  :  — 


DATE. 

FILTER  No.  1. 

FILTER  No.  2. 

March  27, 

Effective  size  0.81  mm.,  uniform- 

Effective size  0.81  mm.,  uniform- 

ity coefficient,  2.2. 

ity  coefficient,  2.2. 

April    21, 

Effective  size  0.18  mm.,  uniform- 

ity coefficient,  2.1. 

May      10, 

Effective  size  0.35  mm.,  uniform- 

Repacked bed  with  same  sand. 

ity  coefficient,  2.0. 

July      29, 

Repacked    bed    with    same    size 

sand. 

Aug.     14, 

Effective  size  0.81  mm.,  uniform- 

ity coefficient,  2.2. 

Considering  these  niters  after  April  15,  when  they  were  started 
in  service  at  regular  and  standard  rates  of  filtration,  Filter  No.  1 
was  in  operation  for  63  days,  of  which  36  days  gave  bacterial  effi- 
ciencies for  the  effluent  of  over  98  per  cent,  and  22  days  gave 
bacterial  efficiencies  of  over  99  per  cent,  with  bacterial  counts  in 
the  filtrate  at  times  as  low  as  2,  4,  8,  and  10  colonies  per  cubic  cen- 
timeter. For  the  same  interval  of  time,  Filter  No.  2  was  ope- 
rated for  69  days,  of  which  41  days  gave  bacterial  efficiencies  of 
more  than  98  per  cent,  and  30  days  gave  bacterial  efficiencies 
of  more  than  99  per  cent,  with  bacterial  counts  in  the  nitrate  as 
low  as  6,  9,  10,  and  12  colonies  per  cubic  centimeter. 

From  July  17  to  July  24,  a  period  of  seven  days,  Filter  No.  2 
was  operated  at  an  average  rate  of  29,043,000  gallons  per  acre  per 
day,  with  an  average  bacterial  efficiency  of  98.5  per  cent.  Dur- 
ing this  period  the  highest  bacterial  efficiency  was  99.9  per  cent, 
the  bacteria  being  reduced  from  9,067  per  cubic  centimeter  in  the 
applied  water  to  10  per  cubic  centimeter  in  the  filtered  water,  and 
the  lowest  bacterial  efficiency  was  92.9  per  cent,  when  the  bacteria 
was  reduced  from  565  per  cubic  centimeter  in  the  applied  water  to 
40  per  cubic  centimeter  in  the  filtered  water. 

The  average  bacterial  efficiency  for  the  Morison  Mechanical 
filter,  using  alum,  from  July  20,  1893,  to  Jan.  30,  1894,*  is  given 
as  follows  :  — 


*  Report  on  Results  Obtained  -with  Experimental  Filters,  Providence,  R.I.,  1896,  pp.  55-57. 


TYPES   OF  SAND   FILTERS.  173 


• 


For  end  growths,  97.21 

For  «  ninety-hour  growths,"  97.86 

From  Aug.  15  to  Sept.  13  (1893),  Filter  No.  1  was  operated 
with  "alum  and  free  flow"  for  a  period  of  23  days,  while  Filter 
No.  2  was  operated  as  a  plain  sand  filter  for  22  days.  During 
this  interval  of  time  both  filters  were  packed  with  sand-grains  of 
an  "  effective  size"  of  0.81  mm.,  and  a  "uniformity  coefficient"  of 
2.2.  The  rates  of  filtration  and  bacterial  efficiencies  are  tabled 
below  :  — 

FILTER  RATE  OF  FILTRATION.  BACTERIA. 

GALLONS  PER  ACRE  PER  DAY.  PERCENTAGE  REMOVED. 

No.  1   (with  alum),  30,100,000  82.11 

No.  2   (without  alum),  30,900,000  89.45 

These  figures  indicate  no  advantage  in  the  use  of  alum,  not- 
withstanding the  rate  of  filtration  was  less  than  one-fourth  of  the 
standard  rate  which  Mr.  Weston  has  proposed  for  filters  of  the 
mechanical  class  using  alum  as  a  coagulant.  Filter  No.  2  was 
always  operated  with  an  "effective  size"  of  sand-grains  of  0.81 
mm.,  while  Filter  No.  1  was  operated  with  sand-grains  of  an 
"effective  size"  of  0.81  mm.,  0.18  mm.,  and  0.35  mm. 

During  the  interval  of  time  taken  for  comparison  of  filtration 
"with  alum"  and  filtration  "without  alum,"  the  "effective  size" 
of  sand-grains,  condition  of  the  applied  water,  and  rates  of  filtra- 
tion were  the  same.  The  "effective  size"  of  sand-grains  for  the 
Morison  mechanical  filter  was  0.59  mm.,  with  a  "uniformity 
coefficient "  of  1.5. 

The  influence  of  sand  finer  in  "effective  size"  than  0.81  mm. 
is  shown  by  comparison  of  the  operation  of  Filter  No.  1,  when 
it  was  packed  with  sand  of  an  "effective  size"  of  grain  0.35  mm., 
with  Filter  No.  2,  which  was  packed  with  sand-grains  of  the  larger 
size. 

The  average  bacterial  efficiencies  of  Filter  No.  1,  operating 
without  alum,  from  May  25  to  July  15,  1893,  a  period  of  42 
days,  during  which  time  the  sand-bed  was  scraped  once,  were  as 
follows  :  — 


174  THE  PURIFICATION  OF   WATER. 

FILTER  No.  1.    Sand-Bed  Scraped  and  Filter  started  in  service  May  15. 

EFFECTIVE  SIZE  OF  SAND,  0.35  MM.     UNIFORMITY  COEFFICIENT,  2.0. 

AVERAGES. 

_  RATE  OF  FILTRATION.  PERCENTAGE  OF 

INTERVAL  OF  TIME.  _  _ 

GALLONS  PER  ACRE  PER  DAY.  BACTERIA  REMOVED. 

May  25-June  13,  2,300,000  98.3 

During  above  test  the  numbers  of  bacteria  per  cubic  centimeter 
in  the  effluent  were  often  below  100,  and  at  times  as  low  as  8,  24, 
and  26. 

Sand-Bed  Scraped  and  Filter  Started  in  Service  June  15. 

AVERAGES. 

RATE  OF  FILTRATION.  PERCENTAGE  OF 

GALLONS  PER  ACRE  PER  DAY.  BACTERIA  REMOVED. 

June  15-July  15  2,280,000  97.9 

During  this  latter  interval  the  numbers  of  bacteria  per  cubic 
centimeter  in  the  filtrate  were  often  less  than  100,  and  at  times 
as  low  as  2,  4,  9,  10,  11,  13,  and  18. 

The  average  bacterial  efficiencies  of  Filter  No.  2,  operating 
without  alum,  from  May  25  to  July  13,  1893,  a  period  of  40  days, 
during  which  time  there  was  no  scraping  of  the  sand-bed,  were  as 
follows  :  — 

FILTER  No.  2.     Sand  Removed  and  Filter  Started  in  service  May  13. 

EFFECTIVE  SIZE  OF  SAND,  0.81  MM.     UNIFORMITY  COEFFICIENT,  2.2. 
AVERAGES. 

RATE  OF  FILTRATION.  PERCENTAGE  OF 

GALLONS  PER  ACRE  PER  DAY.  BACTERIA  REMOVED. 

May  25-June  13  2,316,400  98.1. 

During  this  interval  of  time  the  bacteria  in  the  effluent  were  as 
low  as  14  to  16  per  cubic  centimeter. 

Sand-Bed  Unscraped  Since  Previous  Use. 

AVERAGES. 
T  RATE  OF  FILTRATION.  PERCENTAGE  OF 

GALLONS  PER  ACRE  PER  DAY.  BACTERIA  REMOVED. 

June  15-July  13  2,296,250  97.4 

During  this  interval  of  time  the  numbers  of  bacteria  in  the 
effluent  were  as  low  as  9,  12,  and  16  per  cubic  centimeter. 

A  comparison  of  these  tables  indicates  no  special  advantage  in 
the  sand  of  smaller  size  of  grain. 


TYPES   OF  SAND   FILTERS.  175 

• 

These  results  taken  as  a  whole  clearly  show  that  plain  sand 
filtration  as  conducted  during  the  Providence,  R.I.,  experiments  is 
quite  as  efficient  as  mechanical  filtration  with  "  alum,"  and  is  not 
calculated  to  impart  an  astringency  or  acidity  to  the  filtrate,  which 
may  be  positively  hurtful  to  some  systems. 

Mr.  Weston's  experiments  with  plain  sand  filters  in  the  author's 
opinion  are  entitled  to  more  consideration  than  they  have  been 
given  in  the  official  Report.  Here  are  two  sand  filters,  30  inches 
diameter,  operating  naturally  at  rates  1,000,000  to  35,000,000  gal- 
lons per  acre  per  day,  with  average  bacterial  efficiencies  of  97,  98, 
99,  and  occasionally  100  per  cent  (the  higher  results  sometimes 
being  obtained  with  the  higher  rates  of  filtration)'.  The  average 
efficiency  for  Filter  No.  2,  without  alum,  at  rates  of  25,000,000  to 
35,000,000  gallons  per  acre  per  day  for  about  the  same  length  of 
time,  is  the  same  as  the  average  bacterial  efficiency  of  the  Mori- 
son  mechanical  filter  after  the  sand-bed  was  washed  with  a  solu- 
tion of  caustic  soda. 

LOWELL,    MASS.,    FILTER-BED. 

The  following  description  of  this  filter  is  taken  from  the  Manual 
of  American  Water-Works,  1889-1890,  p.  63.  Population,  78,000. 

Built  in  1876,  in  gravel  between  the  filter  gallery  and  the 
river  :  100  by  114  feet  at  bottom,  which  is  8  feet  below  the  level 
of  the  Pawtucket  dam.  On  the  gravel  is  laid  a  dry  stone  drain, 
15  inches  square  at  the  river  end,  100  feet  long,  and  30  inches 
square  at  the  end  nearest  the  gallery,  where  it  terminates  in  a  10- 
foot  circular  brick  chamber,  connected  with  the  filter  gallery  by  a 
30-inch  pipe.  From  the  central  drain  27  lateral  stone  drains  are 
laid,  each  8  by  12  inches.  The  filtering  materials  consist  of: — 

18  inches  fine  sand. 

6     "         coarse  screened  sand. 
10     "         coarse  gravel  (J-inch  diameter). 
36     "         §-inch  cobble  stones. 
70  inches  total  depth  of  filtering  materials. 

"  In  the  spring  of  1877  a  freshet  deposited  18  inches  of  sand 
and  silt  on  the  filter-bed  ;  and  it  was  necessary  to  admit  some  water 


176  THE   PURIFICATION  OF   WATER. 

directly  from  the  river  until  the  deposit  was  removed  in  Septem- 
ber, when  for  83  days  the  filter-bed  and  gallery  yielded  the  full 
(daily)  supply  to  the  city  of  1,750,000  gallons.  In  1878  the  filter 
furnished  the  full  daily  supply  of  1,879,810  gallons  for  43  days. 
It  was  found  that  with  a  one-inch  silt  deposit  the  filter  yielded  but 
little  water.  From  August,  1878,  to  June,  1879,  the  surface  of  the 
bed  was  not  cleaned,  and  in  this  time  20  inches  of  silt  had  accu- 
mulated. After  being  cleaned,  it  supplied  the  gallery  for  only  9 
days  before  another  inch  of  silt  entirely  stopped  the  yield.  Find- 
ing that  the  bed  needed  cleaning  three  times  a  month,  that  the 
cost  would  be  $25  each  time,  and  that  it  could  only  be  done  when 
the  river  was  low  and  free  from  ice,  further  cleaning  was  given  up, 
until  1888,  when  the  new  inlet  was  put  in  and  the  bed  cleaned,  it 
was  practically  useless,  four-fifths  of  the  water  used  being  pumped 
directly  from  the  river." 

This  filter  consisted  of  a  single  bed  with  no  provision  for  peri- 
odical resting  and  cleaning.  From  the  description  it  would  seem 
that  the  cleaning  and  restoring  of  the  filter  to  its  original  condi- 
tion were  not  thought  of  at  the  time  of  its  construction.  In  fact, 
it  was  expected  to  work  continuously,  and  never  clog  with  inter- 
cepted suspended  matter  and  the  products  of  bacterial  action. 
From  the  dimensions  given,  the  filter  had  an  "  effective  area  "  of 
0.26  of  an  acre,  and  ran  for  83  days,  delivering  water  at  the  rate  of 
6,734,000  gallons  per  acre  per  day.  At  another  time  it  was  ope- 
rated for  43  days  at  the  rate  of  7,230,000  gallons  per  acre  per  day, 
when  it  clogged  and  was  taken  out  of  service.  For  ten  months 
the  filter  was  run  without  cleaning,  during  which  time  20  inches 
of  silt  accumulated  on  the  bed. 

The  statement  that  it  required  cleaning  three  times  each  month 
is  not  remarkable,  considering  the  rate  of  filtration,  but  that  it 
cost  f  25  to  clean  one-quarter  of  an  acre  of  sand  filter  is  remark- 
able. The  cost  of  cleaning  the  filters  of  the  East  London  Water- 
Works  is  $25  per  acre ;  but  this  is  considered  there  a  high  price, 
and  is  accepted  only  to  secure  rapid  work  under  contract,  and  have 
the  filters  out  of  service  for  the  shortest  periods  of  time.  Why 
it  should  cost  four  times  as  much  to  clean  the  Lowell  filter  is 
not  clear,  unless,  as  it  appears,  there  was  no  sedimentation  of  the 


TYPES  OF  SAND   FILTERS.  177 

fj 

Merrimac  River  water  before  it  was  put  on  the  bed.  Assuming, 
however,  that  the  filter  might  have  been  kept  in  successful  opera- 
tion at  a  cost  of  $ 900  per  year,  and  the  average  yield  of  water 
was  1,800,000  gallons  per  clay,  or  657,000,000  gallons  per  year, 
the  cost  would  have  been  less  than  11.40  per  million  gallons ;  a 
very  low  price  indeed. 

It  seems,  however,  that  the  filter  was  not  combined  with  a 
settling-basin,  could  only  be  cleaned  "  when  the  river  was  low  and 
free  from  ice,"  and  no  provision  was  made  for  treatment  of  the 
river  water  when  this  single  filter  was  out  of  service. 

Considering  the  time  it  was  built,  twenty  years  ago,  and  after 
modern  filtration  had  been  established  for  nearly  thirty  years  in 
the  London  Water-Works,  it  is  singular  that  so  many  mistakes 
occurred  in  the  design  of  this  Lowell  filter. 

HUDSON,    N.Y.,    FILTERS. 

The  following  description  of  these  filters  is  taken  from  the 
Manual  of  American  Water-Works,  1889-1890,  p.  152.  Popula- 
tion, 10,000. 

Filters.  —  Built  1874-1875.  Two  of  them  adjoining  the  res- 
ervoir. One  with  an  area  of  9,071  square  feet,  and  the  other  with 
an  area  of  23,017  square  feet  at  top  of  filtering  material.  Water 
is  admitted  to  either  basin  through  masonry  wells,  the  walls  of 
which  are  even  with  the  top  of  the  filtering  materials. 

The  filtering  materials  from  the  top  downward  consist  of  :  — 

6  inches  fine  white  sand. 
18      "       coarse  dark  sand 

6      "       i-inch  gravel. 

6      "       ^-inch  gravel. 

6      "       1-inch  broken  stone. 

6      "       2-inch  broken  stone. 
24      "       4-8-inch  broken  stone. 
72  inches  total  depth  of  filtering  materials. 

"The  bottom  of  the  basin  has  a  6-inch  layer  of  concrete,  slop- 
ing slightly  towards  center  and  outlet.  A  dry  masonry  stone  cul- 
vert leads  along  the  bottom  of  basin  to  an  effluent  chamber,  from 


178  THE  PURIFICATION  OF   WATER. 

which  water  passes  to  a  storage  reservoir,  or  can  be  drawn  directly 
to  the  city.  When  dirty,  the  top  layer  of  fine  sand  is  removed  with 
flat  shovels  to  a  depth  of  one  inch,  washed,  and  replaced.  The 
larger  filter  was  constructed  in  1888." 

The  average  daily  consumption  of  water  was  stated  as  1,483,389 
gallons,  which  with  an  "effective  filtering  area"  of  0.737  acre  for 
the  two  filters,  indicates  an  average  rate  of  filtration  of  2,013,000 
gallons  per  acre  per  day.  These  filters  have  been  in  service  since 
1875. 

POUGHKEEPSIE,   N.Y.,    SETTLING-BASINS    AND    FILTERS. 

The  following  description  of  these  filters  is  taken  from  the 
Manual  of  American  Water -Works  for  1889-1890,  p.  175.  Popu- 
lation, 22,000. 

Settling-Basins  and  Filters.  —  The  former  is  30  feet  above  the 
mean  level  of  the  lower  pump-well,  25  by  60  feet,  by  12  feet  deep, 
and  in  three  compartments.  There  are  two  filter-beds,  each  73^ 
by  200  feet,  by  12  feet  deep,  with  5  feet  of  filtering  materials 
arranged  as  follows  :  — 

24  inches  sand. 

6       "       |-inch  gravel. 

6       "       2-inch  broken  stone. 
24       "       4-8  inch  broken  stone. 
60  inches  total  depth  of  filtering  materials. 

The  materials  rest  on  a  concrete  floor,  in  which  are  open  cul- 
verts conveying  the  filtered  water  to  an  intermediate  basin,  6  by  85 
feet,  by  16  feet  deep.  From  this  it  passes  to  a  reservoir,  28  by  88 
feet,  by  17  feet  deep,  and  from  here  by  408  feet  of  18-inch  pipe 
to  the  pump-well. 

"  The  filter-beds  cost  §54,000.  The  cost  of  removing  ice,  clean- 
ing beds,  and  washing  sand,  in  1888,  was  $809.00  ;  cost  per  million 
gallons,  $1.32  ;  cost  of  repairs  was  $86.00." 

Taking  the  average  daily  consumption  of  water  at  1,669,358 
gallons  per  day,  and  the  effective  filtering  area  as  0.675  acre,  the 
rate  of  filtration  at  the  date  mentioned  was  2,473,100  gallons  per 
acre  per  day.  It  has  doubtless  been  much  higher  since  1888-1889. 
These  filters  have  been  in  service  since  1878. 


TYPES   OF  SAND   FILTERS.  179 

• 
FILTER    GALLERIES. 

These,  as  exemplified  in  the  water-works  of  Lyons  and  Angers, 
France,  are  chambers  in  which  the  water  is  collected  by  infiltration 
from  the  surrounding  pervious  materials.  As  constructed,  they 
consist  of  dry  masonry  walls  and  covers,  placed  at  an  elevation 
below  low  water  in  the  adjacent  river  or  other  source  of  supply, 
and  unlike  filter  beds,  the  materials  through  which  the  water  perco- 
lates to  these  galleries  cannot  be  conveniently  cleaned  or  graded. 
Abroad  it  is  believed  that  these  filter  galleries  collect  water  from 
the  river  or  other  visible  sources ;  but  experience  in  this  country 
indicates  that  such  filter  galleries,  like  wells  sunk  in  the  bank  of  a 
river,  generally  intercept  water  percolating  through  the  drift.  In 
fact,  such  wells  sunk  in  the  banks  of  the  Ohio  River,  within  the 
limestone  formation  of  the  channel  and  watershed,  always  furnish 
water  quite  as  hard  as  that  of  wells  further  inland. 

In  some  situations  these  galleries  doubtless  intercept  or  tap 
an  "  underflow  "  of  streams,  but  such  water  is  not  precisely  water 
filtered  from  these  sources,  but  is  the  natural  percolation  of  water 
through  the  drift  parallel  to  the  streams.  The  remarks  in  Chapters 
II.  and  X.  upon  natural  filtration  through  the  materials  of  the  drift 
apply  to  these  so-called  natural  filter  galleries. 

From  Mr.  Kirkwood's  Filtration  of  River  Waters  *  the  follow- 
ing data  are  taken  on  the  rate  of  percolation  per  acre  of  bottom 
area  of  some  of  these  galleries  :  — 

RATE  OF   PERCOLATION. 

LOCATION.  U.  S.  GALLONS  PER  ACRE  PER  DAY. 

Toulouse,  France,  12,545,280 

Lyons,  «  6,403,320 

Angers,  «  13,068,000  (New  gallery.) 

Perth,  Scotland,  7,927,920 

The  kind  of  water  supplied  by  these  galleries  should  be  that 
of  shallow  wells  sunk  in  the  drift,  and  the  chemical  and  bacterial 
contents  may  be  inferred  from  the  tests  of  water  samples  from 
such  wells  for  any  given  locality.  Aside  from  the  fact  that  these 

*  D.  Van  Nostrand,  N.Y.,  1869. 


180  THE  PURIFICATION  OF   WATER. 

galleries  are  liable  to  intercept  surface  water  insufficiently  filtered, 
and  will  eventually  clog  and  fail  to  supply  a  profitable  amount  of 
water,  the  filtering  materials  are  beyond  the  reach  of  daily  super- 
vision and  manipulation,  and  as  a  general  proposition  such  sources 
are  not  to  be  recommended  for  domestic  water  supply.  There  are 
localities  where  filter  galleries  will  furnish  an  altogether  acceptable 
water  supply  ;  but  very  careful  investigation  of  the  water  quality 
and  environment  of  the  source  should  be  made  before  such  water 
is  adopted  for  drinking  and  dietetic  purposes. 


EUROPEAN    FILTERS. 

From  the  notes  collected  for  the  author  during  1896,  upon  some 
European  filters,  the  following  data  are  taken  with  reference  to 
the  arrangement  and  nature  of  the  filtering  materials,  and  rates 
of  filtration  in  U.  S.  gallons  :  - 

ROTTERDAM,  population,  276,338. 

Water  from  the  River  Maas  carried  for  24  hours  in  settling- 
basins  before  it  is  put  on  the  filters. 

Area  of  filtering  surface,  9  acres  in  18  beds. 
Standard  area  of  filter,  0.50  acre. 

ARRANGEMENT  OF   FILTERING  MATERIALS. 

Sand  at  top  of  bed  (effective  size,  0.34  mm.),*  30  inches. 

Gravel  (over  underdrains),  12       " 

Boulders,  12       " 

Total  depth  of  filtering  materials,  54  inches. 

Head  of  water  on  filters,  42       " 

Average  rate  of  filtration  per  acre  per  day,  1,818,200  gallons. 

Average  bacteria  per  c.  c.  in  river  water,  f  6,000-10,000 

Average  bacteria  per  c.  c.  in  filtrate,  90-99 

Average  bacterial  reduction  by  filtration,  98.82  per  cent. 
Average  present  daily  consumption  of  water,  about     7,000,000  gallons. 

Daily  per  capita  consumption,  25       " 

*  The  effective  size  of  sand-grains  in  this  and  the  following  tables  is  given  on  authority  of 
Mr.  Hazen. 

t  Bacteriological  tests  made  every  day. 


TYPES   OF  SAND   FILTERS.  181 


« 


THE  .HAGUE,  population,  187,545. 
Water  from  wells  sunk  in  the  sand  dunes. 
Area  of  filtering  surface,  3.66  acres  in  6  beds. 
Standard  area  of  filter,  0.61  acre. 

ARRANGEMENT   OF   FILTERING   MATERIALS. 

Fine  dune  sand  at  top  of  filter  (effective  size,  0.19  mm.),    30  inches. 
Gravel,  12       « 

Boulders,  12       " 

Total  depth  of  filtering  materials,  54  inches. 

Head  of  water  on  filters,  39       " 

This  water  is  of  very  excellent  quality  before  it  is  put  on  the 
filter-beds. 

Average  rate  of  filtration  per  acre  per  day  is  1,497,400  gallons, 
which  is  sometimes  increased  to  4,280,000  gallons  per  acre  per 
day. 

The  thickness  of  sand-paring  is  about  |  inch,  the  dirty  sand 
being  given  to  truck  gardeners  for  use  as  a  fertilizer. 

Average  present  daily  consumption  of  water,  about     5,480,000  gallons. 
Daily  per  capita  consumption,  29       " 

AMSTERDAM,  population,  489,496. 

Source  of  water  supply :  Haarlem  sand  dunes  and  River 
Vecht. 

Area  of  filtering  surface,  5.36  acres  in  4  beds,  4.76  acres  in 
7  beds. 

ARRANGEMENT  OF    FILTERING   MATERIALS. 

Fine  dune  sand  at  top  of  bed  (effective  size,  0.17  mm.),  30  inches. - 

Gravel,  12       « 

Boulders  (over  underdrains),  12       " 

Total  depth  of  filtering  materials,  54  inches. 

Head  of  water  on  filters,  39       " 

Two  filters,  each  having  an  area  of  2,860  square  meters  (0.706 
acre),  costing,  it  is  stated,  $20,000  or  114,200  per  acre,  have 
recently  been  built. 


182  THE   PURIFICATION  OF   WATER. 

Rate  of  filtration  per  acre  per  day,  3,208,700  gallons. 

Average  daily  consumption  of  water,  10,331,000       " 

Daily  per  capita  consumption,  21       " 

PARIS  SUBURBS,  population,  600,000. 

Supplied  by  Compagnie  Generate  des  Eaux,  from  Choisy-le- 

Roi,  Nogent-sur-Marne,  and  Neuilly-sur-Marne.  This  company 

uses  the  Anderson  Revolving  Iron  Purifier  and  sand  filters. 

Area  of  filters  at  Choisy-le-Roi,  2.30  acres,  15  beds. 

Area  of  filters  at  Neuilly-sur-Marne,  2.30     "  15     " 

Area  of  filters  at  Nogent-sur-Marne,  0.75     "  4     " 

Total,  5.35  acres,  34  beds. 

ARRANGEMENT   OF   FILTERING  MATERIALS. 

Fine  sand  at  top  of  filter,  24  inches. 
Gravel,  6       " 

Boulders,  6       " 

Total  depth  of  filtering  materials,  36  inches. 

Head  of  water  on  filters,  36       " 

Rate  of  filtration  per  acre  per  day,          I  Amwwm  1   gall°ns. 

^  '±,OUU,UUU  J 


June,  1896,  it  was  claimed  that  the  several  stations  about  Paris 
where  this  process  was  in  operation  were  delivering  17,000,000 
gallons  of  filtered  water  per  diem,  with  a  reduction  of  bacteria 
from  20,000  per  cubic  centimeter  in  the  unfiltered  water  to 
300-400  in  the  filtered  water  (by  the  Miquel  method  of  cultiva- 
tion), indicating  an  efficiency  of  98.25  per  cent. 

With  this  iron  process  the  top  sand  in  the  filters  is  worked 
from  a  maximum  thickness  of  24  inches  to  a  minimum  thickness 
of  1*2  inches.  The  filters  are  open  ;  and  in  winter,  when  an  ice- 
cake  of  sufficient  thickness  is  formed,  the  water  level  is  lowered 
until  the  floating  sheet  of  ice  rests  on  the  sand,  when  some  of  the 
matter  which  has  accumulated  at  the  surface  of  the  sand  and 
clogged  the  filter  adheres  to  the  under  side  of  the  ice,  and  upon 
filling  the  filter  again  from  below  and  floating  the  ice,  the  surface 
of  the  sand  is  opened  and  the  rate  of  filtration  increased. 

A  statement  is  made  in  connection  with  the  Anderson  process 
at  Paris,  which,  if  true,  is  very  significant  ;  i.e.,  that  the  filtered 


TYPES   OF  SAND  FILTERS.  183 

• 

water  may  be  carried  in  storage  for  as  many  as  twenty  days  with- 
out an  increase  in  the  bacterial  contents.  It  is  supposed  that 
the  salts  of  iron  have  an  inhibiting  effect  on  the  growth  of  the 
bacteria,  algae,  etc.,  in  the  treated  water. 

ZURICH,  population  (1892)  93,000. 
Source  of  water  supply :  Lake  Zurich  and  springs. 
Filtering  area,  0.835  acre  in  5  beds. 

Three  covered  filters,  21,690  square  feet,  7,230  square  feet 
each. 

Two  open  filters,  14,967  square  feet,  7,483  square  feet  each. 

ARRANGEMENT   OF   FILTERING   MATERIALS. 

Fine  sand  at  top  of  bed  (effective  size,  0.30  mm.),  32  inches. 

Coarse  sand,  6       « 

Small  gravel,  4      " 

Coarse  gravel  (over  underdrains),  6       " 

Total  depth  of  filtering  materials,  48  inches. 

Head  of  water  on  filters,  39.6    " 

Average  rate  of  filtration  per  acre  per  day,  5,850,000  gallons. 

Average  consumption  of  filtered  water  per  day,  4,884,000       " 

Average  consumption  of  spring  water  per  day,  792,000       " 

Total  average  consumption,  5,676,000  gallons. 

Average  consumption  per  capita  per  day,  61       " 

LONDON. 

According  to  Mr.  Hawksley,*  the  total  area  of  filters  in  use 
by  the  London  companies  (1892)  was  110  acres,  dealing  with 
119,000,000  U.  S.  gallons  per  day,  from  which  it  appears  that  the 
average  rate  of  filtration  was  about  1,800,000  gallons  per  acre 
per  day.  The  average  area  of  the  London  filters  is  about  one 
acre  each. 

*  Appendices  to  Minutes  of  Evidence,  taken  by  Royal  Commission  on  Metropolitan 
Water  Supply,  1893,  p.  347. 


184  THE   PURIFICATION  OF   WATER. 


CHAPTER   XII. 

MECHANICAL   FILTERS. 

THE  mechanical  filter  is  distinctly  an  American  invention,  and 
like  many  inventions  is  primarily  designed  to  accomplish  a  large 
amount  of  work  within  a  small  compass  and  short  time. 

Certain  physical  operations  have  been  wonderfully  improved  in 
both  speed  and  quality  by  modern  invention,  but  it  cannot  be  said 
that  this  is  true  of  water  filtration.  While  the  slowest  rates  of  fil- 
tration do  not  invariably  give  the  best  results,  at  the  same  time 
certain  moderate  rates  per  unit  of  sand  area  cannot  be  increased 
without  risk  of  impairing  the  quality  of  the  filtrate.  The  mechan- 
ical filter  is  expected  to  operate  at  prodigious  rates  per  unit  of  sand 
area,  when  compared  with  the  very  moderate  rate  of  the  European 
type  of  sand  filter. 

This  can  best  be  shown  by  comparison  of  the  rates  of  the  Lon- 
don filters  for  1896  with  the  estimated  best  rate  for  the  Morison 
mechanical  filter  in  the  Providence,  R.I.,  tests  :  — 

RATES  OF  FILTRATION  PER  ACRE  PER  DAY. 

U.    S.   GALLONS. 

Average  rate  for  all  the  London  Filters,  1896,  2,120,000 

Providence  Experimental  Mechanical  Filter,  128,000,000 

The  sand  used  in  the  mechanical  filter  is  of  coarser  grain  than 
in  the  London  filters,  and  this  enormous  difference  of  rate  could 
not  be  maintained  were  it  not  for  two  conditions  not  found  in  the 
operation  of  the  plain  sand  filter.  (1)  The  frequent  washings  of 
the  sand-bed,  and  (2)  the  use  of  alum  as  a  coagulant  to  quickly 
form  on  the  surface  of  the  sand,  the  coagulum  which  takes  the 
place,  but  cannot  be  regarded  as  the  equivalent  of  the  "  Schmutz- 
decke,"  or  natural  film  produced  by  subsidence  of  suspended  matter 
and  bacterial  action  at  the  surface  of  the  plain  sand  filter. 

The  mechanical  filter,  so-called,  is  mechanical  only  so  far  as 


ME  CHA  NIC  A  L    FIL  TERS. 


185 


machinery  operated  by  power  is  applied  for  the  raking  and  agita- 
tion of  the  sand  while  being  cleansed,  and  for  the  regular  dosing 
of  the  applied  water  with  the  alum  solution.  The  process  of  filtra- 
tion, excepting  as  the  flocculent  alum  precipitate  may  affect  it,  is 
altogether  natural. 

Mechanical  filters  may  be  of  two  types,  —  those  which  operate  by 
a  gravity  head  or  draft  on  the  sand-bed,  and  those  which  operate 


Fig.  11.    Jewell  Gravity  Filter. 

under  pressure ;  sometimes  the  full  pressure  of  the  water-works 
system.  In  either  case  the  machine  consists  of  a  tank  of  wood  or 
metal,  vertical  or  horizontal,  in  which  the  bed  of  sand  is  carried 
on  a  system  of  screens  or  strainers,  and  arranged  with  a  rake  or 
agitator,  which  is  slowly  revolved  around  in  the  tank  through  the 
bed  of  sand.  When  the  sand  is  being  stirred  by  the  revolving 
rake  a  reverse  current  of  water  is  passed  through  the  filter-bed,  to 
wash  away  such  suspended  matter  as  may  have  been  intercepted 


186 


THE  PURIFICATION  OF   WATER. 


Top  of  Bed -^ 


from  the  applied  water  during  the  previous  interval  of  use  of  the 
filter. 

The  Gravity  Mechanical  Filter  shown  in  Fig.  11  is  manufac- 
tured by  the  O.  H.  Jewell  Filter  Company  of  Chicago,  and  con- 
sists of  a  settling-tank  and  sand- 
bed  combined  in  one  tank,  the 
lower  part  containing  the  settling- 
tank  and  the  upper  part  the  filter. 
The  head  is  produced  by  a  vacu- 
um in  the  effluent  pipes  under  the 
sand-bed.  In  this  type  of  filter 
the  revolving  rakes  are  at  rest  on 
the  sand-bed  while  the  filter  is  in 
service,  and  are  put  in  rotation 
after  the  sand-bed  has  been  "loos- 
ened up "  for  washing  by  a  re- 
verse current  of  water.  Provision 
is  made  for  washing  the  sand 
either  with  filtered  or  unfiltered 
water. 

The  most  elaborate  Report  now 
available  on  the  performance  of 
this  type  of  filter  is  that  made  by 
Mr.  Edmund  B.  Weston,  C.E.,  on 
what  is  termed  the  "Morison  Ex- 
perimental Filter,"  from  which, 
through  the  kindness  of  Mr.  J.  Her- 
bert Shedd,  city  'engineer  of  Provi- 
dence, R.I.,  the  author  is  permitted 
to  abstract  for  the  purpose  of  this  work. 

The  drawing,  Fig.  12,  is  reproduced  from  the  Report  men- 
tioned, in  which  the  filter  is  described  as  follows  by  Mr.  Weston :  — 

"  Upon  the  screens  shown  at  the  bottom  of  the  filter,  the  filtering  medium 
or  filter-bed  of  crushed  quartz  is  located,  the  total  depth  being  two  (2)  feet 
and  ten  (10)  inches.  The  effective  size  of  the  grains  of  quartz  which  com- 
pose the  upper  two  (2)  feet  is  0.59  mm.,  and  the  uniformity  co-efficient  1.5. 


Outlet 


Height  14- ft,  Diameter  30  inches. 


Fig.  12.    Morison  Experimental  Filter, 
Providence,  R.I. 


MECHANICAL   FILTERS.  187 

The  lower  ten  (10)  inches  of  quartz  is  of  a  much  toarser  quality.  The 
screens  allow  the  water  to  pass  through  them  during  the  different  operations 
of  working  the  filter,  downward  while  filtering,  and  upward  during  the  pro- 
cess of  washing  the  filter-bed.  They  prevent  the  quartz  or  any  foreign  sub- 
stances from  entering  the  collecting-pipes  or  passing  off  with  the  filtered  water. 

"  The  manner  in  which  the  filter  was  operated  during  the  experiments  is 
as  follows  :  At  the  end  of  a  run,  or  immediately  before  starting  the  filter,  the 
filter-bed  was  thoroughly  washed  by  forcing  up  through  the  screens  and  filter- 
bed  a  reverse  flow  of  water  under  pressure,  the  mechanical  rake  or  agitator, 
shown  in  the  cut,  being  operated  at  the  same  time,  which  added  materially  to 
the  efficient  cleansing  of  the  filter-bed.  The  water  was  forced  up  through  the 
bed,  and  the  agitator  kept  in  motion,  until  the  water  flowing  from  the  overflow 
drain-pipe  was  as  clear  as  it  was  before  it  was  used  for  washing  the  filter-bed. 
The  necessary  valves  were  then  operated,  and  the  water  and  the  sulphate  of 
alumina  turned  onto  the  filter. 

"  The  rates  of  the  filtration  of  water  mentioned  in  this  report  all  represent 
an  average  rate  per  acre  per  24  hours  unless  otherwise  specified.  The  standard 
rate  of  filtration  decided  upon  at  the  commencement  of  the  experiments  was 
128,000,000  gallons  per  acre  per  24  hours.  When  the  term  sulphate  of  alu- 
mina is  used,  it  is  intended  as  an  abbreviation  of  basic  sulphate  of  alumina. 

"In  making  the  experiments  with  this  filter  the  following  details  were 
carefully  investigated,  as  well  as  many  other  points  relative  to  the  efficient 
working  of  the  filter,  viz.  :  — 

"  1.    The  chemicals  best  adapted  for  the  purification  of  the  Pawtuxet  River 

water. 
"  2.    The  best  method  of  applying  the  chemicals,  and  the  quantity  to  add 

to  the  applied  water  for  each  gallon  of  water  filtered. 
"  3.    If  any  portion  of  the  chemicals  that  were  added  to  the  applied  water 

were  present  in  the  filtered  water. 
"  4.    The  rate  in  gallons  per  acre  per  24  hours  which  could  be  efficiently 

filtered. 

"  5.    The  bacteriological  and  chemical  purification  of  the  water. 
"  6.    The  percentage  which  the  color  of  the  water  would  be  reduced  by 

filtration. 

"  7.    The  washing  of  the  filter-bed. 

"  8.    The  time  which  would  be  required  for  washing  the  filter-bed. 
"  9.    The  quantity  of  water  which  would  be  required  to  wash  the  filter-bed. 
"  10.    The  quantity  of  water  which  it  would  be  necessary  to  run  to  waste 

after  washing  the  filter-bed. 

"  11.  The  length  of  time  which  the  filter  would  run  after  starting,  before  it 
would  be  necessary  to  shut  down  and  wash  the  filter-bed  on  ac- 
count of  the  water  gradually  rising  to  its  prescribed  limit  in  the 
filter,  owing  to  the  filter-bed  becoming  gradually  clogged  up. 


188  THE   PURIFICATION  OF   WATER. 

"  12.  The  effective  stability  of  the  quartz  and  supplementary  precipitate 
bed;  viz.,  whether  it  could  be  depended  upon  to  do  its  work 
thoroughly  during  the  whole  of  the  time  that  the  filter  was  in 
operation,  or  whether  at  times  it  would  be  liable  to  crack  or 
break,  or  have  its  efficiency  reduced  in  any  manner. 

"13.  The  loss  of  head  due  to  the  water  flowing  through  the  filter-beds 
and  screens. 

"  During  the  preliminary  experiments,  the  chemicals  used  were  basic  sul- 
phate of  alumina,  chloride  of  alumina,  carbonate  of  soda,  bicarbonate  of  soda, 
caustic  soda,  and  chloride  of  iron.  The  soda  salts  were  used  in  connection 
with  sulphate  of  alumina.  It  was  found,  however,  that  basic  sulphate  of  alu- 
mina added  to  the  applied  water  produced  the  best  results.  Basic  sulphate  of 
alumina,  therefore,  is  the  only  chemical  that  has  been  used  since  the  prelimi- 
nary experiments. 

"  The  theory  of  mechanical  filtration,  when  basic  sulphate  of  alumina  has 
been  added  to  the  applied  water,  may  be  described  as  follows :  The  alumina 
causes  an  artificial  precipitation.  A  portion  of  the  alumina  is  decomposed, 
forming  sulphates  of  other  bases  and  a  flocculent  precipitate  of  aluminic 
hydrate.  A  portion  of  it  also  combines  directly  with  the  organic  matter 
present  in  the  water,  coagulating  the  same,  and  thus  helping  to  increase  the 
precipitation.  A  sufficient  quantity  of  the  precipitate  having  been  deposited 
upon  the  top  of  the  sand  or  quartz-bed  of  the  filter,  and  plugged  into  the  in- 
terstices of  the  upper  layer  of  sand  or  quartz-grains,  the  filter  is  ready  for 
service. 

"  At  the  commencement  of  the  experiments  with  the  Morison  mechanical 
filter,  it  was  discovered  that  satisfactory  results  could  not  be  obtained  by  sim- 
ply dropping  the  sulphate  of  alumina  into  the  applied  water  at  the  rate  of  \ 
grain  per  gallon,  as  it  would  take  from  one  to  three  hours  after  the  filter  was 
started  for  a  sufficient  quantity  of  the  precipitate  to  form  in  order  to  do  good 
work.  After  experimenting  in  different  ways,  it  was  found  that  if  a  "free 
flow  "  of  about  a  pint  of  coagulant,  containing  about  nine  hundred  and  eleven 
(911)  grains  of  sulphate  of  alumina  for  an  average  rate  of  filtration  of  about 
128,000,000  gallons  per  acre  per  24  hours,  was  allowed  to  run  into  the  filter, 
immediately  after  the  water  was  let  on,  in  a  space  of  time  of  not  more  than 
six  (6)  minutes,  a  quantity  of  coagulant  corresponding  to  one-half  (£)  grain  of 
sulphate  of  alumina  per  gallon  of  filtered  water  being  dropped  in  at  the  same 
time  from  a  different  receptacle  than  that  containing  the  "free  flow,"  a  suffi- 
cient amount  of  precipitate  would  be  formed  to  do  good  work  in  one-half  hour 
or  less  after  the  water  commenced  to  flow  from  the  filter. 

"  At  the  commencement  of  a  run  of  the  filter,  the  applied  water  was  at 
first  gradually  let  into  the  filter,  it  being  regulated  at  the  same  time.  After 
the  normal  quantity  commenced  to  flow  into  the  filter  a  constant  flow  was 
maintained,  and  the  depth  of  water  in  the  filter  gradually  increased  proportion- 


MECHANICAL    FILTERS.  189 

ately  during  the  run  as  the  supplementary  precipitate  bed. was  formed,  and 
the  filter-bed  became  plugged  with  precipitate.  The  rise  of  water  practically 
accommodated  itself  to  the  circumstances,  and  caused  a  constant  flow  of 
water  through  the  filter,  which  I  considered  extremely  essential  in  order  to 
obtain  good  results. 

"  One  of  the  most  serious  problems  that  it  was  necessary  to  solve  when 
the  experiments  were  commenced,  was  to  ascertain  if  the  basic  sulphate  of 
alumina  that  was  added  to  the  applied  water  was  entirely  decomposed  before 
the  water  was  discharged  from  the  filter." 

A  sample  of  the  sulphate  of  alumina  used  had  the  following 
composition  :  - 

ONE-HALF  (£)   GRAIN 
PER  CENT. 

CONTAINS  IN  GRAINS. 

Insoluble  residue,  0.52  0.0026 

Alumina  (A12O8),  15.78  0.0789 

Sulphur  Trioxide  (SO3),  36.79  0.1840 

Water  (by  difference),  46.91  0.2345 

100.00  0.5000 

After  a  series  of  experiments  upon  this  filter,  extending  from 
April  5,  1893,  to  Jan.  80,  1894,  Mr.  Weston  reached  the  follow- 
ing conclusions  :  — 

The  chemical  best  adapted  for  the  purification  of  the  Pawtuxet 
River  water  was  basic  sulphate  of  alumina,  the  quality  used  con- 
taining 15.8  to  17.5  per  cent  of  alumina. 

The  best  method  of  applying  the  chemicals,  and  the  quantity 
required  per  gallon  of  water,  have  been  described  as  \  grain  per 
gallon  plus  "free  flow  "  for  not  more  than  six  minutes,  equivalent 
to  T%  grain  of  sulphate  of  alumina  per  gallon  of  water  for  an  aver- 
age run  of  16  hours,  43  minutes. 

Upon  the  appearance  of  any  portion  of  the  chemicals  added  to 
the  water  in  the  filtrate,  he  says  :  — 

"  The  results  that  I  have  mentioned,  that  were  obtained  by  applying  the 
logwood  and  acetic  acid  test  for  alum,  in  conjunction  with  filter  paper,  have 
demonstrated,  I  think,  that  none  of  the  basic  sulphate  of  alumina  was  present 
during  the  experiments  in  the  filtered  water,  in  rts  original  state,  after  the  water 
had  been  flowing  from  the  filter  twenty-one  (21)  minutes.  The  only  indica- 
tion of  alumina  found  in  the  filtered  water  was  a  minute  quantity  of  finely  sus- 
pended hydrate,  resulting  from  the  addition  of  the  alumina,  that  came  through 
the  filter-bed  with  the  water  that  was  being  filtered.  .  .  . 


190  THE   PURIFICATION  OF   WATER. 

"  An  analysis  by  Professor  Thomas  M.  Drown  .  .  .  shows  that  0.0292  of  a 
grain  of  alumina  (A12  O3)  per  gallon  was  found  in  a  sample  of  Pawtuxet  River 
water,  that  had  been  taken  directly  from  the  river,  and  afterwards  filtered 
through  a  double  thickness  of  Swedish  paper,  and  that  0.0584  of  a  grain  of 
alumina  (A10  O3)  per  gallon  was  found  in  a  sample  of  the  same  water  after 
sulphate  of  alumina  had  been  added  to  it,  at  the  rate  of  one-half  (A)  grain  per 
gallon  ;  and  the  very  slight  flocculent  precipitate  produced,  filtered  off  through  a 
double  thickness  of  filter  paper,  shows  an  increase  of  alumina  (A12  O3)  of 
0.0292  of  a  grain." 

The  rate  at  which  the  water  was  "  filtered  successfully  "  ranged 
from  90,000,000  gallons  to  193,000,000  gallons  per  acre  per  24 
hours,  "the  average  rate  of  nitration  being  about  128,000,000" 
gallons  per  acre. 

The  average  bacterial  efficiency  of  the  filter  for  two  short  in- 
tervals of  time,  selected  from  the  ten  months  of  experiment,  viz., 
Oct.  17  to  Nov.  11,  1893,  a  period  of  25  days,  and  from  Jan.  24  to 
Jan.  30,  1894,  a  period  of  7  days,  was  a  reduction  of  98.6  per  cent 
of  the  bacterial  contents  of  the  applied  water.  For  various  rea- 
sons Mr.  Weston  rejects  the  work  of  the  filter  for  87  per  cent  of 
the  time  of  test,  and  bases  the  bacterial  efficiency  upon  these  two 
short  intervals  of  time.  Upon  the  subject  of  bacterial  efficiency, 
Mr.  Weston  says  :  — 

"  I  do  not  consider  that  the  efficiency  of  a  filter  should  be  entirely  based 
upon  the  average  results  obtained,  although  this  is  generally  the  standard  upon 
which  the  efficiency  is  based,  but  that  the  worst  results  obtained  should  be 
duly  considered.  In  order  to  present  my  ideas  upon  this  subject  more  clearly 
I  will  assume  a  rather  improbable  case.  For  example,  if  100  individual  results 
were  used  in  working  up  an  average,  90  of  these  results  might  each  show  an 
efficiency  of  100  per  cent,  and  10  of  them  might  each  show  an  efficiency  of 
only  80  per  cent,  or  in  other  words,  10  per  cent  of  the  total  results  would  be  18 
per  cent  below  the  average  result,  which  in  my  opinion  would  be  sufficient 
grounds  to  condemn  a  filter.  Yet  the  average  of  the  whole  number  would  be 
98.0  per  cent,  which  is  a  very  good  result." 

The  author  concurs  with  Mr.  Weston,  with  the  additional  sug- 
gestion that  the  efficiency  of  a  filter  for  hygienic  purposes  should 
be  measured  altogether  by  its  worst  results,  and  not  by  the  best 
or  even  the  average  results. 

The  filtration  of  a  public  water  supply  should  assume  that  under 


MECHANICAL   FILTERS.  191 

the  most  unfavorable  conditions  of  the  applied  water,  the  filtrate 
shall  comply  with  a  given  standard  of  hygiene,  and  any  estimate 
of  the  influence  of  such  water  upon  the  health  of  the  people  who 
drink  it  should  be  based  upon  these  worst  conditions.  In  short, 
the  nitration  of  a  public  water  supply  should  assume  a  certain 
uniformity  in  the  quality  of  the  nitrate,  without  regard  to  the  man- 
ual operation  of  the  filters,  or  to  the  condition  of  applied  water. 
The  filter  itself  should  be  so  constructed,  and  the  regulations  under 
which  it  is  operated  such,  that  the  quality  of  the  filtrate  shall  sat- 
isfy some  acceptable  standard  at  all  times.  Phenomena  and  phys- 
ical aberrations  may  be  tolerated  in  scientific  investigations,  but 
the  practical  purification  of  a  polluted  public  water  supply  should 
involve  no  phenomena  and  no  vagaries  to  the  prejudice  of  the 
public  health. 

The  reduction  of  color  by  filtration,  using  alum  with  the  "  Mor- 
ison  filter,"  ranged  from  66.3  per  cent  for  the  night  observations 
to  77.9  per  cent  as  an  average  for  the  day  observations. 

The  average  time  required  to  wash  the  bed  of  sand  in  the  filter 
was  about  11  minutes  ;  and  the  amount  of  water  required  to  wash 
the  sand-bed,  and  the  amount  which  was  run  to  waste  after  the 
filter  was  washed  and  started  in  service,  was  about  7.8  per  cent  of 
the  quantity  filtered.  Of  this  quantity  4.9  per  cent  was  required 
to  wash  the  filter-bed,  and  2.9  per  cent  was  run  to  waste  after  the 
filter  was  started  again. 

The  average  length  of  "run"  of  the  filter  between  cleansings 
was  16  hours  and  43  minutes,  and  the  average  loss  of  head 
for  a  delivery  of  128,000,000  gallons  per  acre  per  diem  of  24 
hours  was  2.44  feet.  Mr.  Weston  estimates  the  cost  of  ope- 
rating a  Morison  mechanical  filter  plant  of  15,000,000  U.  S.  gal- 
lons daily  capacity,  as  $5.69  per  one  million  gallons  of  water 
filtered. 

From  a  single  experiment  by  Dr.  T.  M.  Drown,  in  connection 
with  the  Providence  filter  tests,  it  appears  that  the  addition  of 
one-half  (£)  grain  per  gallon  of  the  sulphate  of  alumina  to  the 
Pawtuxet  River  water,  increased  the  alumina  from  0.0292  grain 
per  gallon  to  0.0584  grain  per  gallon,  and  increased  the  sulphuric 
acid  in  the  water  from  0.3129  to  0.5214  grain  per  gallon. 


192  THE  PURIFICATION  OF   WATER. 

Although  Mr.  Western  has  made  a  very  long  and  exhaustive 
study  of  the  mechanical  filter,  with  "alum  "  as  a  coagulant,  in  his 
summary  he  rejects  the  majority  of  his  data,  and  draws  his  con- 
clusions from  :  — 

Two  days'  operation  of  the  filter  in  July. 
Seven  days'  operation  of  the  filter  in  October. 
Eight  days'  operation  of  the  filter  in  November. 
Two  days'  operation  of  the  filter  in  December. 
Twenty-four  days'  operation  of  the  filter  in  January. 

Or  out  of  ten  months'  continuous  experiment,  he  takes  43  days, 
as  showing  the  possibilities  of  this  method  of  water  filtration  ;  of 
which  time,  six  days  embrace  a  treatment  of  the  sand-bed  hitherto 
untried  with  any  type  of  filter.  The  average  amount  of  alum 
used  during  these  43  days  was  about  T7o  grain  per  gallon  of 
water. 

So  far  as  the  chemical  and  bacterial  reductions  in  the  applied 
water  are  concerned,  it  may  be  accepted  that  the  mechanical  filter, 
used  with  "  alum  "  as  a  coagulant,  will  accomplish  about  the  same 
results  as  will  natural  filtration ;  but  with  the  latter  no  injurious 
property  can  be  imparted  to  the  water,  while  with  "alum  "  proper- 
ties more  objectionable  than  the  pollution  sought  to  be  removed 
may  be  found  in  the  filtrate. 

The  following  costs  of  construction  and  operation  of  mechanical 
and  plain  sand  filters  are  taken  from  estimates  made  by  Mr. 
Weston  for  the  city  of  Providence,  R.I.  The  cost  of  filters  is 
based  on  an  available  daily  capacity  of  15,000,000  gallons. 

MECHANICAL  FILTERS. 


NUMBER  AND  KIND. 

COST  OF  FILTERS 
PER  MILLION  GALLONS  OF 
DAILY  CAPACITY. 

COST  OF  FILTRATION 
PER  MILLION  GALLONS  OF 
WATER  TREATED. 

60  Steel  Filters, 
60  Cypress    " 
51  Steel 
51  Cypress    " 

$16,344.80 
15,296.80 
14,160.30 
13  262.30 

$7.67 
7.86 
7.25 
7.41 

MECHANICAL   FILTERS, 


193 


PLAIN  SAND  FILTERS. 


KIND  OF  FILTERS. 

COST  OF  FILTERS 
PER  MILLION  GALLONS  OF 
DAILY  CAPACITY. 

COST  OF  FILTRATION 
PER  MILLION  GALLONS  OF 
WATER  TREATED. 

Filters  with  vaulted 
masonry  coverings, 
Filters  with  timber  coverings, 
Open  filters, 

$35,000.00 
21,906.53 
19,414.66 

$8.86 
8.14 
6.87 

In  the  figures  for  cost  of  operation  of  the  mechanical  filters, 
the  cost,  including  alum,  is  taken  in  all  cases  at  §4.52  per  million 
gallons  of  water  treated ;  and  the  cost  of  operation  of  the  plain 
sand  filters,  as  deduced  by  Mr.  Weston  from  the  Reports  of  the 
Massachusetts  State  Board  of  Health  at  Lawrence,  is  taken  at 
84.39  per  million  gallons  of  water  treated. 

The  cost  per  million  gallons  of  water  filtered  is  taken  in  the 
table  as  the  whole  cost,  including  interest  at  four  per  cent  on  cost 
of  filters,  buildings,  and  all  appurtenances,  and  charges  for  deterio- 
ration of  plant,  cost  of  chemicals  (for  mechanical  filters),  and  all 
labor  required  to  operate  the  works. 

Other  uses  of  the  mechanical  filter,  in  several  cities  in  New 
Jersey,  are  given  in  an  interesting  paper  by  Mr.  M.  N.  Baker,  C.E., 
contributed  to  the  New  Jersey  Sanitary  Association,  1895,  from 
which  the  following  quotations  are  made  :  — 

"Without  attempting  to  trace  the  various  stages  through  which  the  me- 
chanical filter  has  passed,  it  may  be  said  that  it  aims  to  purify  large  volumes 
of  water  with  a  small  body  of  filtering  material,  relying  upon  frequent  wash- 
ings to  keep  the  material  clean." 

"  Mechanical  filters  are  now  used  on  over  one  hundred  American  water 
supplies,  against  perhaps  ten  filter-bed  plants  worthy  the  name.  Many  factors 
have  contributed  to  the  greater  use  of  mechanical  than  slow  sand  filters  in  this 
country.  Chief  of  these  is  the  commercial  aspect  of  mechanical  filtration  and 
a  former  entire  misconception  of  the  principles  of,  and  the  results  which  may 
be  accomplished  with,  filter-beds.  Mechanical  filters  have  been  vigorously 
pushed  by  sales  agents  wherever  bad  water  has  been  reported.  Filter-beds 
stand  or  fall  on  their  own  merits,  as  they  are  not  patented,  and  no  one  is  finan- 
cially interested  in  securing  their  adoption.  The  misconceptions  regarding 
filter-beds  have  come  to  light  with  the  recognition  of  the  germ  theory  of  dis- 
ease, and  improved  methods  and  interpretation  of  the  bacterial  examinations 


194  THE   PURIFICATION  OF   WATER. 

of  water.     For  years  water  contained  disease  and  other  germs,  and  filter-beds 
removed  many  of  them  without  any  one  knowing  it. 

"  Most  of  the  plants  built  by  the  mechanical  filter  companies  have  been 
designed  to  remove  suspended  matter  and  color  where  these  were  so  marked 
as  to  render  the  water  almost  intolerable.  These  ends  many  of  the  mechan- 
ical filters  have  accomplished  most  admirably.  Meanwhile,  most  communities 
have  remained  satisfied  with  water  that  looks  well,  without  regard  to  the  dan- 
gerous impurities  it  may  contain,  or  have  secured  new  supplies  from  more 
favorable  sources.  With  the  modern  advances  in  sanitary  science,  attention 
has  recently  been  turned  to  the  importance  of  removing  sewage  impurities  from 
polluted  waters,  if  the  latter  must  be  used ;  and  of  late  filter-beds  and  mechan- 
ical filters  have  been  constructed  with  this  end  in  view. 

"  I  believe  it  probable  that  good  bacteriological  results  are  possible  with 
mechanical  filtration.  I  am  certain  that  they  can  be  obtained  with  sand  filter- 
beds,  and  that  suspended  matter,  vegetable  stains,  and  iron  can  be  removed 
by  means  of  mechanical  filters. 

"  Filter-beds  will  also  remove  color,  suspended  matter,  and  iron,  if  supple- 
mented by  aeration,  as  well  as  sewage  impurities." 

The  following  data  from  the  Somerville  and  Raritan  Water- 
Works  are  given  by  Mr.  Baker:  — 

Source  of  supply,  Raritan  River. 

Population  supplied  (1890),  6,417. 

Capacity  of  filter,  1,500,000  gallons  per  day. 

Average  daily  filtration  for  1894,  about  800,000  gallons. 

Cost  of  filters,  exclusive  of  buildings,  $15,600.  Of  the  opera- 
tion of  these  filters,  Mr.  Baker  says  :  — 

"  As  this  plant  was  put  in  to  remove  matters  in  suspension,  its  efficiency 
should  be  judged  by  its  removal  of  total  solids.  These  were  reduced  from 
26.72  to  15.98  parts  per  100,000,  a  reduction  of  10.74  parts  in  26.72,  or  about 
42  per  cent.  The  color  is  reported  as  having  been  changed  from  dark  brown 
to  faint.  The  reduction  of  organic  matter,  as  indicated  by  the  albuminoid  am- 
monia, was  nearly  70  per  cent." 

The  analyses  from  which  these  figures  are  taken  contain  meas- 
urable quantities  of  nitrites  and  nitrates  for  the  river  water,  while 
none  are  given  for  the 'filtered  water.  Successful  filtration  gene- 
rally indicates  an  increase  of  nitrites  and  nitrates.  Referring  to 
the  ammonias,  the  albuminoid  ammonia  is  reduced  from  .049  to 
.015,  and  the  "  free  "  ammonia  is  increased  from  .013  to  .052  part 
per  100,000. 


MECHANICAL   FILTERS. 


195 


The  permanent  hardness  of  the  water  by  addition  of  sulphates 
was  increased  from  3.75  parts  to  6.75  parts  per  100,000,  while  the 
temporary  hardness  (carbonates)  was  reduced  from  3.50  parts  to 
0.50  part  per  100,000,  the  gain  in  sulphates  being  exactly  bal- 
anced by  the  loss  in  carbonates.  Alum  is  used  as  the  coagulant. 

Long  Branch,  according  to  Mr.  Baker,  has  a  mechanical  filter 
plant  of  3,000,000  gallons  daily  capacity,  treating  water  from  Whale 
Pond  Brook.  These  are  pressure  filters,  working  under  a  head  of 
40  pounds.  The  loss  of  head  in  passing  the  water  through  the 
filter  is  stated  at  five-tenths  pound.  Five  per  cent  of  the  total 
water  purified  is  required  for  washing  the  sand  in  the  filters.  The 
filters,  including  buildings,  cost  $31,000. 

From  the  analyses  given  in  Mr.  Baker's  paper  the  following 
data  are  taken  :  — 


PARTS  PER  100,000  OF  WATER. 

BEFORE  FILTRATION. 

AFTER  FILTRATION. 

Free  ammonia, 

0.132 

0.0035 

Albuminoid  ammonia, 

0.0445 

0.0095 

Nitrites, 

0.0025 

0.0015 

Nitrates, 

0.087 

0.087 

Permanent  hardness, 

.  .  . 

1.00 

Temporary       " 

2.25 

1.24 

Total  solids, 

9.52 

.       7.14 

Organic  and  volatile  matters, 

4.24 

1.74 

Bacteria  per  c.  c., 

268.00 

3.0 

Potash  alum  is  used  in  this  filter. 


THE    JEWELL    GRAVITY    FILTERS    AT    LORAIN,    OHIO. 

Through  the  kindness  of  the  Jewell  Filter  Company  of  Chicago, 
the  author  is  enabled  to  include  the  results  of  its  process  of  water 
purification  at  Lorain,  Ohio,  for  the  months  of  March  and  April, 
1897.  From  the  notes  furnished,  which  are  quite  complete,  the 
following  resumt  is  drawn  :  — 

MARCH,  1897. 

Bacteria  in  untreated  water,  3,725 

"         "    filtered  water,    _  88 

Percentage  of  reduction,  97.61 

Grains  of  alum  used  per  gallon  of  water,  1.87 

Average  water  treated  daily,  2,712,400  gallons. 


196  THE   PURIFICATION  OF   WATER. 

APRIL,  1807. 

Bacteria  in  untreated  water,  1,835 

"         "    filtered  water,  31 

Percentage  of  reduction,  98.29 

Grains  of  alum  used  per  gallon  of  water,  1.99 

Average  water  treated  daily,  2,774,500  gallons. 

In  this  case  the  alum  per  gallon  of  water  treated  is  about 
2  grains,  which,  at  ITGO  cent  per  pound,  represents  a  cost  of  |4.80 
per  million  gallons  of  water  for  the  chemical  alone,  an  amount 
equal  to  the  average  cost  of  plain  sand  nitration,  according  to  the 
reports  from  works  where  such  filters  are  in  daily  use.  The  actual 
consumption  of  alum  per  gallon  of  water  is  over  three  times  the 
amount  which  Mr.  Weston,  in  the  report  on  mechanical  niters 
for  the  city  of  Providence,  regarded  as  necessary  for  proper  fil- 
tration. 

Adding  to  the  cost  for  alum  the  estimate  by  Mr.  Weston 
of  the  cost  for  labor,  wash-water,  water  run  to  waste,  etc.,  viz., 
$2.80,  the  total  cost  of  mechanical  nitration,  based  on  the  Lo- 
rain  experience,  will  be  $7.60  per  one  million  gallons  of  water 
treated. 

According  to  Mr.  James  H.  Blessing,  of  the  New  York  Filter 
Company,  in  a  statement  to  the  city  of  Albany,  N.Y.,*  the  cost 
for  mechanical  filtration  at  that  place,  including  labor,  alum,  etc., 
will  be  from  $2.44  to  $2.94  per  million  gallons.  This  estimate  is 
very  difficult  to  reconcile  with  the  estimated  cost  at  Providence, 
and  the  probable  actual  cost  at  Lorain  ;  in  fact,  Mr.  Blessing 
makes  the  cost  for  Albany  from  one-half  to  two-thirds  the  cost 
for  alum  alone  at  Lorain,  and  considerably  less  than  one-half  of 
the  total  cost  as  figured  by  Mr.  Weston  for  the  proposed  me- 
chanical filter  plant  for  Providence,  R.I. 

MECHANICAL   FILTERS,    ALBANY,    N.Y. 

Mr.  Hazen,f  in  his  report  on  filtration  for  Albany,  estimates 
the  cost  of  mechanical  filtration  as  follows  :  — 

*  An  Address  to  the  Common  Council,  Feb.  27,  1897. 

t  Report  to  Board  of  Water  Commissioners,  Albany,  Feb.  13,  1897,  p.  27. 


MECHANICAL   FILTERS. 


197 


COST  OF  FILTRATION  PER  MILLION  GALLONS. 


LOCATION  OF  FILTERS. 

LUMBER  DISTRICT. 

BLEECKER  RESERVOIR. 

Labor  and  power  for  operation  of  filters, 
Alum,  143  Ibs.  at  1.6/, 
Wash-water, 

$1.50 
2.29 

$1.50 
2.29 
0.50 

Total, 

3.79 

4.29 

Mr.  Blessing's  estimates, 

2.44 

2.94 

The  estimated  cost  of  mechanical  filters  for  Albany  is  given  as 
follows  :  — 

COST  OF  MECHANICAL  FILTERS  PER  MILLION  GALLONS  OF  DAILY  CAPACITY. 


LOCATION. 

HAZEN. 

BLESSING. 

Lumber  district, 
Bleecker  Reservoir, 

$12.938.24 
12,118.22 

$  6,064.42 
10,431.37 

The  cost  of  filtration  quoted  for  Albany  does  not  include  (as 
in  the  report)  the  cost  of  lifting  the  water  to  the  filters,  which  will 
vary  in  different  locations,  and  with  gravity  sources  may  not  be 
required  at  all.  The  cost  of  filters  includes  the  pro  rata  allowance 
for  contingencies.  Mr.  Hazen  estimates  on  gravity  filters  for  both 
locations.  Mr.  Blessing  estimates  on  gravity  filters  for  the  lum- 
ber district,  and  on  pressure  filters  for  the  Bleecker  reservoir. 

The  prices  for  filters  per  million  gallons  of  daily  capacity  do 
not  include  land,  nor  such  structures  as  are  required  at  Albany  to 
make  the  filtered  water  available  in  service. 

MECHANICAL   FILTRATION    FOR    PHILADELPHIA. 

From  a  proposition  of  the  Morison-Jewell  Filtration  Company 
to  the  city  of  Philadelphia  *  the  following  data  is  by  permission 
extracted  :  — 

Daily  capacity  of  filters,  30,000,000  gals. 

Rate  of  filtration  per  acre  of  sand  area  per  day,  128,000,000     " 
Time  allowed  for  subsidence  of  water  in  settling-tanks,     One  hour. 

Total  cost  of  filters,  foundations,  and  buildings,  $300,000.00 
Cost  per  1,000,000  gallons  of  capacity,  $10,000.00 

*  June  8, 1897. 


OF  THB 


UNIVERSITY 


198  THE  PURIFICATION  OF   WATER. 

The  manufacturers'  estimated  cost  for  operation  of  these  filters, 
with  an  allowance  of  f  grain  of  sulphate  of  alumina  per  gallon  of 
water,  is  given  as  $3.61  per  one  million  gallons  of  water  filtered, 
which  would  be  increased  to  $6.43  per  million  gallons  if  the  con- 
sumption of  alum  should  be  as  high  as  2  grains  per  gallon. 

MECHANICAL   FILTERS,    ELMIRA,    N.Y. 

The  city  of  Elmira,  N.Y.,  is  supplied  with  water  from  Morison- 
Jewell  mechanical  filters,  using  sulphate  of  alumina  as  a  coagulant. 
These  filters  have  a  daily  capacity  of  6,000,000  gallons,  and  are 
operated  at  the  rate  of  100,000,000  gallons  per  acre  per  day  of  24 
hours.  The  water  passes  through  the  settling-tanks  by  continuous 
flow  at  a  rate  which  is  equivalent  to  the  detention  of  the  raw  river 
water  in  the  tanks  for  about  30  minutes  before  it  passes  to  the 
filters.  Dr.  Ravenel,*  of  the  University  of  Pennsylvania,  has  made 
the  following  bacteriological  analyses  of  the  water  before  and  after 
filtration. 

The  first  of  the  following  tables  gives  the  bacterial  results  for 
mechanical  filtration  without  a  coagulant,  while  the  second  shows 
the  bacterial  efficiency  with  basic  sulphate  of  alumina  used  at  the 
rate  of  1.4  grain  per  gallon  of  water  :  — 

BACTERIAL   CONTENTS   OF  WATER,   WITHOUT  COAGULANT. 


DATE. 

RAW  WATER. 

AFTER  PASSING 
SETTLING-TANK. 

FILTERED  WATER. 

June  10,  1897. 

885  per  c.  c. 

746  per  c.  c. 

36  per  c.  c. 

11    " 

513    »      « 

556    «      » 

Samples  lost. 

12      " 

625    «      « 

527    «      " 

40  per  c.  c. 

13      « 

351    "      " 

208    "      « 

132    «      " 

14      « 

434    «      « 

366    "      " 

34    «      " 

15      « 

425    «      « 

216    «      « 

13    «      " 

16      « 

566    "      " 

407    "      " 

15    «      " 

17      " 

432    »      " 

358    "      " 

21    "      « 

BACTERIAL  CONTENTS  OF  WATER,  USING  BASIC  SULPHATE  OF  ALUMINA 
1&  GRAIN  PER  GALLON  OF  WATER. 


DATE.  RAW  WATER.  sSuN™.  FILTERED  WATER. 

June  10,  1897.    885  per  c.  c.    576  per  c.  c.     26  per  c.  c. 

11  «      513  "   "     413  "   «      40  »   " 

12  «  625    »      «  457     "      "  12     »      " 
Communicated  by  the  Morison-  Jewell  Filtration  Company,  New  York,  July,  1897. 


MECHANICAL   FILTERS.  199 


DATE. 

RAW  WATER. 

AFTER  MASSING 
SETTLING-TANK. 

FILTERED  WATER. 

June  13,  1897. 

351  per  c.  c. 

129  per  c.  c. 

10  per  c.  c. 

14      " 

434    «      « 

258    «      « 

0    "      " 

15      « 

425    "      « 

333     »      « 

6     "      « 

16      « 

566     "      « 

315    «      « 

13    «      « 

17      « 

432    «      » 

117    «      « 

12    "      « 

In  these  tests  the  water  was  taken  from  the  Chemung  River, 
and  carried  for  short  intervals  of  time  in  settling-tanks.  For  the 
first  test  without,  and  for  the  second  test  with  a  coagulant. 

The  average  numbers  of  bacteria,  and  bacterial  efficiencies 
of  sedimentation  and  filtration,  without  a  coagulant,  were  as  fol- 
lows :  — 

Average  bacteria  in  river  water,  529      per  c.  c. 

Average  bacteria  in  subsided  water,  423       "      " 

Average  bacteria  in  filtered  water,  26.5    "      " 
Reduction  of  bacteria  by  subsidence,  20     per  cent. 

Reduction  of  bacteria  by  subsidence  and  filtration,  95       "      " 

(In  striking  the  average  of  bacteria  per  c.  c.  for  the  filtered 
water  without  a  coagulant,  the  determination  for  June  13  is 
omitted  ;  as  the  figures  given  clearly  indicate  an  abnormal  result, 
the  cause  of  which  is  not  explained  in  the  excerpt  of  the  report 
in  possession  of  the  author.) 

In  the  second  test  a  coagulant  was  used,  with  the  following 
average  numbers  of  bacteria  per  c.  c.  of  water  and  bacterial 
efficiencies,  by  subsidence  and  filtration  :  — 

Average  bacteria  in  river  water,  529        per  c.  c. 

Average  bacteria  in  subsided  water,  325         "      " 

Average  bacteria  in  filtered  water,  15         "      " 

Reduction  of  bacteria  by  subsidence,  38.6    per  cent. 

Reduction  of  bacteria  by  subsidence  and  filtration,  97.16     "      « 

The  addition  of  sulphate  of  alumina  to  the  Chemung  water 
increased  the  efficiency  of  subsidence  and  filtration  2.16  per  cent, 
but  in  this  instance  the  percentage  reductions  are  of  minor 
importance  to  the  low  numbers  of  bacteria  found  in  the  fil- 
trates. 


200  THE  PURIFICATION  OF   WATER. 

THE  USE  OF  ALUM  FOR  FILTRATION. 

If  the  decomposition  of  alum  in  mechanical  filters  depends 
upon  the  amount  of  bases,  as  lime,  soda,  etc.,  in  the  water,  then 
no  free  or  unappropriated  sulphuric  acid  can  at  any  time  be  pres- 
ent, because  all  such  will  be  found  in  combination  with  the  alu- 
mina (alum),  or  with  the  lime,  etc.,  as  sulphates  ;  and  in  this 
case  an  excess  of  alum  applied  to  the  water  would  result  in  a 
hydrated  sulphate  of  alumina,  some  of  which  may  appear  in  the 
nitrate.  Alum  can  be  dissolved  in  distilled  water  wholly  free  from 
organic  matter  or  earthy  salts  ;  but  no  decomposition  of  the  alum 
will  in  such  case  occur,  because  of  the  lack  of  a  base  to  appro- 
priate or  unite  with  the  sulphuric  acid.  Astringency  would  be 
imparted  to  the  water ;  and  a  physiological  question  then  arises, 
upon  the  effect  on  the  absorbent  vessels  of  the  digestive  tract,  of 
the  continuous  use  of  water  containing  an  astringent. 

So  far  as  information  from  medical  sources  has  come  to  the 
author  upon  this  question,  it  indicates  an  objection  to  the  continu- 
ous use  of  a  drinking-water  purified  by  alum  ;  the  disorders  trace- 
able to  it  being  impaired  digestion,  irritation  of  the  mucous 
membrane  of  the  stomach,  and  when  gastric  troubles  already  exist, 
a  dangerous  aggravation  of  these  may  follow  the  continuous  use 
of  water  containing  perceptible  astringent  properties.  For  the 
bath  and  laundry,  and  for  some  industrial  purposes,  water  puri- 
fied by  an  addition  of  alum  is  well  known  to  be  objectionable. 

When  mechanical  filters  are  used  for  the  treatment  with  alum 
of  polluted  soft  waters,  as  are  the  waters  of  many  of  the  rivers 
of  the  central  and  western  portions  of  the  United  States,  lime  as 
milk  of  lime  is  sometimes  added  to  the  water  before  the  alum  is 
introduced,  to  furnish  a  base  for  the  sulphuric  acid  in  the  sulphate 
of  alumina  to  unite  with.  This  practice,  the  author  is  informed,  is 
in  use  in  several  water- works  supplied  with  Jewell  filters,  with  an 
improvement  over  the  use  of  alum  alone,  in  the  quality  of  the 
filtrate,  and  a  reduced  cost  for  chemicals.  In  the  case  of  one  city 
using  Mississippi  River  water,  it  is  reported  that,  by  the  addition 
of  lime  to  the  water,  the  work  of  the  filters  is  more  regular,  and 
the  consumption  of  sulphate  of  alumina  kept  within  2  grains  per 
million  gallons  of  water  treated. 


MECHANICAL   FILTERS,  201 


• 


The  superintendent  of  a  Western  water- works,  in  writing  to 
the  author,  says  :  — 

"  When  the  river  is  soft,  which  is  the  case  after  heavy  rains,  we  use  lime- 
water  in  the  pump-well,  thus  supplying  carbonate  of  lime  for  the  alumina  to 
act  upon.  This  has  proven  an  economical  measure,  as  less  alumina  is  required 
when  the  carbonates  are  present  in  large  quantities,  and  compared  with  sul- 
phate of  alumina,  lime  is  inexpensive." 

The  published  circular  of  one  of  the  prominent  manufacturers 
of  mechanical  niters  contains  the  statement :  "  As  a  general  rule, 
when  operating  niters  at  full  capacity  .  .  .  the  amount  of  alum 
.  .  .  required  varies  from  TV  to  2  grains  per  gallon,"  and  "within 
certain  limits  the  alum  required  is  inversely  proportional  to  the 
rate  of  filtration."  The  smaller  amount  of  alum  mentioned  (yV 
grain  per  gallon)  is  very  much  less  than  the  amount  reported  to 
the  author  from  any  public  water-works  which  employs  mechan- 
ical nitration.  Indeed,  the  larger  amount  (2  grains  per  gallon) 
seems  to  more  nearly  represent  the  consumption  of  alum  in 
practice. 

The  author  has  been  informed  by  manufacturers  and  users 
of  mechanical  filters,  that  one  of  the  difficulties  with  the  use  of 
alum  in  the  waters  of  our  Western  rivers  is  the  variable  quantity 
required  for  good  results  from  day  to  day.  That  while  \  grain 
or  less  per  gallon  of  water  would  be  sufficient  one  day,  6  grains 
would  be  necessary  to  obtain  satisfactory  results  another  day. 
This  represents  not  only  a  large  cost  for  alum,  but  raises  a  ques- 
tion of  the  reliability  of  a  process  of  water  purification  subject  to 
such  a  wide  range  of  behavior  in  actual  service ;  and  this  large 
variation  in  the  quantity  of  coagulant  required,  it  is  stated,  is 
not  always  accompanied  by  known  corresponding  changes  in  the 
quality  of  the  unfiltered  water. 

The  table  on  page  202  shows  the  influence  of  rate  of  filtration 
and  variable  quantities  of  alum  per  gallon  of  applied  water  on  the 
bacterial  efficiency  of  the  Lorain  filters.* 

Before  dismissing  this  subject,  the  author  desires  to  quote  a 
pertinent  paragraph  in  conclusion  of  a  report  to  the  Philadelphia 

*  Ohio  Sanitary  Bulletin,  Columbus,  Ohio,  October,  1897,  p.  117. 


202 


THE   PURIFICATION  OF   WATER. 


LORAIN,  OHIO,    MECHANICAL    FILTERS. 
(From  Examinations  by  MR.  F.  S.  HOLLIS.) 


BACTERIA  PER  C.C.  OF  WATER. 

PERCENTAGES. 

RATE  OF  FILTRATION. 

ALUM. 

BACTERIA 

GALLONS  PER  ACRE 
PER  DAY. 

GRAINS 
PER  GALLON. 

LAKE  WATER. 

FILTRATE. 

BACTERIAL 
REDUCTION. 

REMAINING 

IN 

FILTRATE. 

66,489,984 

2.58 

1,441 

16 

98.9 

1.1 

68,999,040 

2.50 

385 

6 

98.4 

1.6 

69,626,304 

2.27 

367 

9 

97.5 

2.5 

80,289,792 

1.07 

154 

14 

90.9 

9.1 

71,508,096 

0.94 

189 

26 

86.3 

13.7 

Water  Department,  by  Drs.  N.  Wiley  Thomas  and  John  Marshall, 
on  the  subject  of  "alum  "  filtration  for  the  city  water  supply  :  — 

"  It  appears  practically  impossible  to  rapidly  filter  the  city's  supply  with- 
out the  use  of  a  coagulant ;  and  while  any  method  of  filtration  must  of  neces- 
sity be  largely  experimental,  yet  in  view  of  the  unsatisfactory  results  of  our 
examination  of  the  water  obtained  from  the  Roeske  filter,  and  in  consideration 
of  the  approximation  of  the  Long  Branch  filter  to  the  spirit  of  the  specifica- 
tions —  the  water  after  treatment  being  sensibly  improved  —  (although  it  does 
not  literally  fulfill  the  conditions  in  the  specifications  stated,  yet  it  might  pos- 
sibly do  so  at  Belmont),  we  beg  leave  to  suggest  the  erection  and  operation  of 
a  plant  of  the  character  proposed  by  the  New  York  Filter  Company  at  the 
Belmont  Water-Works,  under  the  considerations  proposed,  provided  that  every 
possible  precaution  be  taken  to  prevent  an  excessive  use  of  alum,  if  this  sub- 
stance be  employed  as  a  coagulant ;  and,  if  the  sulphate  of  alumina  be  selected, 
that  corresponding  care  be  exercised  that  it  shall  be  free  from  dangerous  im- 
purities, and  shall  be  introduced  only  in  sufficient  amount  to  produce  the 
necessary  coagulation ;  and  finally  that  limestone  be  made  a  part  of  the  filter- 
bed,  to  insure  the  presence  of  an  adequate  amount  of  lime  compounds  not 
already  converted  into  sulphate,  to  take  up  the  products  of  the  decomposition 
of  the  alum,  as  well  as  to  facilitate  the  breaking  up  of  that  compound." 

An  examination  of  the  Manual  of  American  Water-  Works  for 
1897  reveals  the  use  of  various  kinds  of  filters  in  the  water-works 
of  one  hundred  and  sixty-one  cities  and  villages.  About  two- 
thirds  of  this  number  are  represented  by  the  different  forms  of 
mechanical  filters,  of  which  the  largest  works  are  collected  in 
the  table  on  page  203.  The  daily  aggregate  capacity  of  all  the 
mechanical  filters  in  water-works  of  the  United  States  is  about 
190,000,000  gallons. 


MECHANICAL   FILTERS. 


203 


CITY. 

DAILY 
CAPACITY  IN 

GALLONS. 

CITY. 

DAILY 
CAPACITY  IN 
GALLONS. 

Wilkes-Barre,  Pa., 

10,000,000 

Cedar  Rapids,  Iowa, 

4,000,000 

Chattanooga,  Term., 

9,000,000 

Elgin,  III, 

4,000,000 

Davenport,  Iowa, 

7,500,000 

Newport,  R.  I., 

4,000,000 

Atlanta,  Ga., 

7,000,000 

Burlington,  Iowra, 

3,500,000 

Elmira,  N.  Y., 

6,000,000 

Biddeford  and  Saco,  Me., 

3,000,000 

Oakland,  Cal., 

6,000,000 

Columbia,  S.  C., 

3,000,000 

Quincy,  111., 

5,000,000 

Decatur,  III, 

3,000,000 

Bangor,  Me., 

5,000,000 

Greenwich,  Conn., 

3,000,000 

Little  Rock,  Ark., 

5,000,000 

Keokuk,  Iowa, 

3,000,000 

Knoxville,  Tenn., 

5,000,000 

Lorain,  Ohio, 

3,000,000 

Niagara  Falls,  N.  Y., 

4,500,000 

Long  Branch,  N.  J., 

3,000,000 

Terre  Haute,  Ind., 

4,500,000 

The  only  large  city  which  has  attempted  to  purify  its  water 
supply  by  alum  and  mechanical  filtration  is  New  Orleans.*  Louis- 
ville, Ky.,  has  been  conducting  experiments  for  the  past  two  years 
upon  mechanical  nitration  with  alum,  the  results  of  which  are  not 
yet  available  by  the  public.  The  typhoid  fever  statistics  of  the 
smaller  cities  using  mechanical  filters  have  not  been  compiled,  but 
the  author's  investigations  along  this  line  indicate  a  lower  effici- 
ency for  rapid  sand  nitration  with  alum,  than  by  plain  slow  sand 
nitration  as  employed  in  the  purification  of  polluted  waters  abroad. 

"  While  much  is  claimed  for  the  bacterial  efficiency  of  mechan- 
ical filters,  the  fact  remains  that  the  claims  are  not  so  firmly  veri- 
fied by  scientific  research  as  are  those  of  slow  sand  filtration."  f 


REMOVAL   OF   IRON   FROM    GROUND   WATERS. 

From  Mr.  Baker's  description  of  the  mechanical  filters  used  in 
connection  with  the  water-works  of  Asbury  Park,  NJ.,J  the  follow- 
ing information  has  been  drawn  :  — 

The  filters  were  introduced  to  reduce  the  amount  of  iron  in  the 
ground  water  which  constitutes  the  supply  for  these  works.  The 
capacity  is  2,000,000  gallons  per  acre  per  day,  and  each  pair  of  fil- 
ters consists  of  two  steel  tanks,  6  feet  diameter  and  28  feet  long, 

*  Nineteenth  Annual  Report,  New  Orleans  Water-Works  Company,  1897,  p.  5. 
f  Manual  of  American  Water-Works,  New  York,  1897,  p.  N. 
t  Proceedings  New  Jersey  Sanitary  Association,  1895,  p.  92. 


204  THE  PURIFICATION  OF   WATER. 

of  f-inch  plates,  with  double  riveted  longitudinal  seams.  The  first 
tank  of  each  pair  of  filters  contains  quartz  or  sand,  and  the  second 
tank  contains  animal  charcoal.  The  depth  of  filtering  material  is 
about  four  feet.  During  winter  the  filters  are  washed  once  every 
24  hours,  and  during  summer  once  every  12  hours.  No  coagulant 
is  used.  Before  reaching  the  filters  the  water  is  aerated  by  the 
Pohle  air  lifts  which  are  used  to  raise  the  water  from  the  wells  to 
the  receiving-tanks.  The  water  is  obtained  from  7  wells,  4^-inch 
casings,  each  600  feet  deep,  and  2  wells,  6-inch  casings,  one  1,021 
feet  and  the  other  1,132  feet  deep.  The  cost  of  the  filters,  includ- 
ing foundations,  is  stated  as  120,000. 

From  experiments  by  Dr.  T.  M.  Drown  the  following  net  results 
were  obtained  :  — 

The  iron  in  solution  in  the  water  of  the  two  deeper  wells  was 
1.125  and  1.1378  parts  per  100,000  respectively.  For  the  600 
feet  deep  wells,  from  several  determinations,  the  iron  amounted  to 
0.1791  part  per  100,000. 

Aeration  and  filtration  of  the  water  gave  the  following  reduc- 
tions in  the  amount  of  iron  :  — 

Filtering  through  sand  alone,  87.9  per  cent, 

u  «  H        a  92.7  « 

«  u  «        u  96.9  « 

«  «  "        "  95.5  " 

u  a  n        u  97.7  " 

"  "  "  and  charcoal,     95.0  " 

«  "  "        "  «  98.0  " 

n  n  a.        u  a  98.2  " 

Concerning  the  necessity  of  filtration  through  charcoal,  Dr. 
Drown  says  :  — 

"  If  we  take  the  last  two  days  only,  when  the  pumps  were  working  at  their 
maximum  rate,  the  removal  of  iron  by  the  sand  filter  was  98.3  per  cent,  and  by 
both  filters  98.51  per  cent,  or  only  0.21  per  cent  additional  removal  by  the 
charcoal  filter." 

The  filters  at  Asbury  Park  have  been  in  operation  since  Janu- 
ary, 1895  ;  they  are  of  the  pressure  type,  the  water  being  pumped 
under  a  pressure  of  54.5  pounds  to  the  consumers,  with  a  loss  of 
3  to  5  pounds  in  passing  the  filters. 


MECHANICAL   FILTERS.  205 

The  reduction  of  iron  in  ground  waters  by  aeration,  and  filtra- 
tion through  sand,  has  been  practiced  for  some  years  in  Germany. 

Dr.  Dunbar,  the  director  of  the  Hamburg  Institute  of  Hygiene, 
has  made  quite  an  extensive  investigation  of  the  various  processes 
employed,*  from  which  the  following  facts  are  taken  :  — 

The  earlier  method,  pointed  out  independently  by  Anklam  and 
by  Oesten,  consists  of  aeration  of  such  water  in  long  canals,  or  by 
dropping  the  water  in  finely  divided  streams  from  an  altitude  of 
2  meters  (6.5  feet).  With  some  waters  this  has  given  good  re- 
sults, with  others  it  has  failed  almost  entirely.  Thus  in  one 
instance  the  oxide  of  iron  (Fe2  O3)  was  1.10  mg.  per  liter  in  the 
raw  water,  and  0  in  the  treated  water,  showing  a  complete  reduc- 
tion or  removal  of  the  iron.  In  another  instance  the  reduction  of 
the  iron  oxide  was  only  from  24  mg.  to  20  mg.  per  liter,  showing 
a  reduction  or  removal  of  only  16  to  17  per  cent  of  the  iron  in  the 
untreated  water. 

The  Piefke  method  consists  of  the  percolation  of  the  water 
through  a  chamber  filled  with  coke.  The  efficiency  of  this  method 
is  said  to  be  increased  as  the  coke  becomes  covered  with  the  iron 
and  other  substances  precipitated  from  the  water.  Upon  a  large 
scale  this  method  has  reduced  the  iron  in  ground  water  from  40 
mg.  per  liter  to  merely  a  trace. 

The  Kronke  method  of  iron  reduction  in  water  consists  of  the 
treatment  of  the  water  first  by  chemicals,  usually  a  salt  of  iron, 
and  then  by  lime.  By  this  process  all  the  iron  can  be  eliminated 
from  water.  The  chemicals  consist  of  1  gram  of  ferric  chloride 
and  5  to  10  grams  of  lime  to  100  liter  of  water.  The  apparatus 
required  consists  of  a  mixing-tank,  a  measuring-vessel,  and  a  filter 
to  intercept  the  precipitated  iron.  The  use  of  this  process  has 
given  reductions  of  the  iron  in  the  untreated  water  as  shown  in 
the  first  table  on  the  following  page. 

The  cost  of  the  iron  salts  and  lime  required  by  this  method, 
according  to  Dr.  Dunbar,  varies  from  ^  to  \  cent  per  cubic  meter 
(264.2  gallons)  of  water. 

The  process  for  reduction  of  iron  in  water  by  flow  through  a 

*  "  On  the  Nature  and  Treatment  of  Ground  Waters  Containing  Iron,  etc.,"  Zettschrift 
fur  Hygiene,  vol  xxii.,  1896,  p.  68  et  seq. 


206 


THE  PURIFICATION  OF   WATER. 


OXIDE   OF   IRON   IN   WATER. 


UNTREATED  WATER. 
MG.  PER  LITER. 

TREATED  WATER. 
MG.  PER  LITER. 

PERCENTAGE  OF 
REDUCTION. 

8.00 

0.10 

98.75 

9.20 

0.00 

100.00 

10.00 

0.00 

100.00 

1.95 

0.10 

94.87 

24.00 

0.15 

99.37 

bed  of  animal  charcoal,  in  which  the  deferrization  is  due  either  to 
oxidation  in  the  pores  of  the  filter,  or  to  the  influence  of  the  calca- 
reous constituents  of  the  filter  material,  shows  in  some  instances  a 
complete  removal  of  the  iron.  Such  filters  diminish  in  efficiency 
from  day  to  day,  but  can  be  restored  to  their  original  capacity  by 
immersion  of  the  animal  charcoal  in  dilute  hydrochloric  acid.  The 
influence  of  time  on.  such  a  filter  is  shown  in  the  following 
table :  *  - 

REDUCTION   OF   OXIDE  OF    IRON    IN  WATER   BY   FLOW  THROUGH 
A   BED  OF  ANIMAL  CHARCOAL. 


DAYS  OF 
SERVICE. 

ORIGINAL  FEZ  O3 
MG.  PER  LITER. 

AFTER  FLOW 
THROUGH  FILTER 
(FE203). 
MG.  PER  LITER. 

PERCENTAGE  OF 
REDUCTION. 

1 

.    . 

0.25 

98.96 

2 

.    . 

0.25 

98.96 

3 

.    . 

0.40 

98.34 

4 

24.0 

0.55 

97.71 

5 

24.5 

0.65 

97.35 

6 

0.80 

96.74 

7 

.    . 

0.75 

96.94 

8 

.   . 

1.50 

93.88 

9 

.    . 

2.50 

89.80 

10 

. 

1.50 

93.88 

11 

1.40 

94.29 

The  Massachusetts  State  Board  of  Health  has  very  carefully 
investigated  the  subject  of  iron  in  ground  waters,  and  the  follow- 
ing paragraph  has  been  taken  from  its  Twenty-seventh  Annual 
Report :  — 

*  "  On  the  Nature  and  Treatment  of  Ground  Waters  Containing  Iron,  etc.,"  Zeitschrift 
fiir  Hygiene,  vol.  xxii.,  1896,  p.  135. 


MECHANICAL   FILTERS.  207 

0 

"  Many  experiments  have  been  made  at  different  times  with  a  view  to  a 
removal  of  the  iron  by  oxidation  and  subsequent  filtration  of  the  water  through 
sand  to  remove  the  precipitated  iron  oxide.  The  results  obtained  by  this 
means  have  been  very  variable.  But  in  general  it  may  be  said,  that  when  the 
iron  is  present  in  the  water  in  small  amount,  say,  not  over  0.3  of  a  part  per 
100,000,  the  iron  will  separate  out  of  the  water  almost  completely  on  exposure 
to  the  air  for  24  to  36  hours,  in  the  form  of  a  rusty  precipitate,  which  can  be 
removed  entirely  by  filtration  through  sand  at  a  rapid  rate.  Forced  aeration 
by  filtering  through  sand  with  a  current  of  air  was  found  in  almost  all  cases  to 
hasten  the  oxidation  and  separation  of  the  iron  oxide." 

The  performance  of  the  iron  reduction  plant  at  Reading,  Mass., 
from  a  series  of  analyses  extending  from  July  27,  1896,  to  Oct.  6, 
1896,  indicates  reductions  ranging  from  83.16  to  100  per  cent  of 
the  amount  originally  in  the  water.  In  this  instance  the  plant  con- 
sists of  a  Warren  mechanical  filter,  used  with  lime,  forced  aeration, 
and  sulphate  of  alumina,  for  the  precipitation  and  coagulation  of 
the  iron.  In  one  instance  the  iron  originally  in  the  water  is  stated 
as  0.356  part  per  100,000,  and  in  the  treated  water  as  0.020 
part  per  100,000,  showing  a  reduction  of  94  per  cent.*  Analyses 
by  Professor  Henry  Carmichael,  Boston,  September,  1896,  gave 
the  iron  oxide  in  the  original  water  as  0.1070  part  per  100,000, 
and  in  the  filtered  water  as  0.0107  part  per  100,000,  showing  a 
reduction  by  the  Warren  process  of  90  per  cent. 

*  "Removal   of   Iron   from  Ground  Water,"  M.   N.  Baker,  Engineering  News,  Nov.  26, 
1896. 


208  THE   PURIFICATION  OF   WATER. 


CHAPTER  XIII. 

HAMBURG  SETTLING-BASINS  AND  FILTERS. 

THE  following  description  of  the  water  purification  works  at 
Hamburg  is  based  upon  a  very  elaborate  paper  by  Mr.  Meyer,  the 
chief  engineer.*  These  works  were  under  construction  at  the 
time  of  the  cholera  epidemic,  September,  1892,  and  stimulated  by 
this  awful  calamity  (which  was  largely  due  to  the  condition  of  the 
water  supply  of  the  city),  the  work  on  the  filters  during  the  inter- 
vening months  was  carried  on  day  and  night  by  the  aid  of  electric 
lights,  and  finished  in  May  of  the  following  year. 

These  works  are  the  most  modern  in  all  proportions  and  ap- 
pointments, and  illustrate  on  a  grand  scale  the  combined  effect 
of  sedimentation  and  filtration  on  the  water  from  the  River  Elbe  ; 
a  source  of  supply  which  will  bear  comparison  with  some  of  the 
sewage-polluted  rivers  of  this  country. 

The  water  is  first  pumped  from  the  Norder  Elbe  into  four 
settling-basins,  each  393.6  feet  wide  by  1,148  feet  long,  and  11.15 
feet  deep.  The  effective  depth  of  these  basins  is  stated  as  6.56 
feet,  and  the  available  water  capacity  of  all  as  about  84,500,000 
U.  S.  gallons.  The  usual  time  allowed  for  sedimentation  is  19  to 
30  hours,  according  to  information  furnished  the  author  by  Mr. 
Rud  Schroder,  inspector  of  the  Hamburg  Water- Works. 

These  settling-basins  are  excavated  in  the  earth,  with  inside 
slopes  three  horizontal  to  one  vertical.  The  bottom  and  slopes 
are  puddled,  and  covered  with  a  pavement  of  brick  or  tile.  Of 
the  total  depth  of  water,  4.59  feet  is  below  the  invert  of  the 
effluent  pipe,  and  represents  the  space  allowed  for  accumulation 
of  mud,  silt,  etc.,  in  the  bottom  of  the  basin.  The  material  pre- 
cipitated by  subsidence  from  the  river  water  can  from  time  to 

*  Das  Wasserwerk  der  Frein  und  Hansestadt  Hamburg,  by  F.  Andreas  Meyer,  Ham- 
burg, 1894. 


HAMBURG  SETTLING  BASINS  AND   FILTERS. 


209 


time  be  flushed  out  of  the  basins  through 
a  36-inch  cast-iron  waste-pipe,  which  is  con- 
trolled by  a  stop  valve  in  the  embankment. 

"  The  main  conduit  of 
masonry,  from  the  settling- 
basins  on  Bill  warder  Island 
to  the  filters  on  the  Kalte 
Hofe,  is  9,020  feet  long,  8.5 
feet  diameter,  until  it  reaches 
the  group  of  filters,  around 
which  it  is  reduced  to  5.25 
feet  diameter  for  a  length  of 
885.6  feet.  From  this  main  conduit  short 
branch  pipes  3.936  feet  diameter  lead  to  the 
influent  chambers  of  each  of  the  filters." 

"  The  influent  chamber  to  each  filter  con- 
tains two  compartments.  In  the  first  is  placed 
a  double-seat  (balanced)  valve  connected  by 
means  of  a  lever  or  walking-beam  to  a  float  in 
the  second  compartment,  by  means  of  which, 
when  the  water  on  the  filter  reaches  the  de- 
sired elevation,  the  valve  is  closed  automatic- 
ally. The  water  flows  upon  the  filter  through 
two  openings  in  the  side  of  the  chamber,  the 
bottoms  of  which  are  at  the  same  elevation  as 
the  surface  of  the  sand  in  the 
filters  (see  Fig.  13). 

"All    the     filters    except 
one  are  rectangular   in  plan, 
this    one    being    shaped    to 
the  topography  of  the  island. 
All  the  filters  are  open,  and 
constructed  with  inside  slopes, 
two   horizontal  to   one   verti- 
cal.    Sloped  embankments  were  used,  partly 
because  the   marshy  soil  would  not  support 
walls  of  masonry,  and  partly  because  the  ac- 


210  THE   PURIFICATION  OF   WATER. 

tion  of  the  expanding  ice  on  the  paved  slopes  would  not  so  readily 
injure  them." 

According  to  the  Hamburg  officials,  open  filters  have  an  ad- 
vantage over  closed  filters  in  being  more  easily  cleaned,  operated, 
and  inspected.  Exposure  to  the  air  can  work  no  injury  to  the 
water  on  the  filter ;  upon  the  contrary,  it  is  held  that  the  decom- 
position of  organic  matter  is  aided  by  contact  with  the  air.  The 
water  in  the  settling-basins  and  filters,  which  becomes  warmer  than 
the  river  water  during  the  summer,  is  again  cooled  in  the  long  con- 
duits and  covered  reservoir.* 

"  The  location  of  Hamburg,  near  the  German  Ocean,  precludes 
the  probability  of  ice  forming  on  the  filters  for  long  periods.  It 
should  be  mentioned,  however,  that  during  the  winter  the  water  in 
the  River  Elbe  is  generally  quite  clear,  and  the  intervals  between 
scrapings  of  the  sand  are  therefore  considerably  lengthened. 

"  The  Hamburg  filters  have  very  large  dimensions  compared 
with  other  works,  namely,  7,650  square  meters  (1.89  acre)  each. 
The  objection  to  large  filters  heretofore  has  been  that  the  clean- 
ing of  them  is  not  so  easily  accomplished  as  are  those  of  small 
area.  If  this  objection  was  real,  there  is  no  doubt  that  smaller 
beds  would  be  made  of  those  now  used  in  the  Hamburg  water- 
works. The  experience  had  with  these  filters  seems  to  show  that 
the  cleaning  can  be  easily  accomplished  ;  and  there  is  no  reason 
why  the  beds  should  be  made  smaller  than  is  necessary  from  an 
economic  standpoint,  in  order  not  to  have  an  excess  of  filtering 
area  in  reserve,  or  out  of  service  during  the  time  of  scraping  and 
renewal  of  the  sand.  For  this  reason  the  size  of  the  single  filters 
in  any  system  of  filtration  should  not  exceed  a  given  per  cent  of 
the  total  filtering  area.  In  these  works,  containing  eighteen 
filters,  it  does  not  appear  that  the  unit  area  has  been  made  too 
large.  By  reducing  the  areas  of  filters,  the  walls  of  which  are 
sloped,  a  great  deal  of  otherwise  useful  surface  would  be  lost  in 
the  increased  length  of  embankments,  the  number  of  influent  and 
effluent  chambers  would  be  increased,  and  the  land  required  for 

*  The  author  is  informed  that  the  water  in  the  covered  storage  reservoirs  at  Rothenburgs- 
ort  is  usually  cooler  by  2  degrees  Fahr.  in  summer  than  the  water  as  it  is  pumped  from  the 
river  to  the  settling-basins. 


HAMBURG  SETTLING-BASINS  AND   FILTERS. 


211 


a  given  effective  filtering  area  would  also  be  increased.  Finally, 
the  cost  of  construction  and  operation  of  the  works  would  be 
increased  on  the  one  hand,  while,  on  the  other,  the  convenience  of 
operation  would  be  diminished.  It  therefore  seemed  to  be  more 
advantageous  for  Hamburg  to  have  large  filter-beds  ;  and  the  expe- 
rience of  four  years  has  demonstrated  that  neither  in  the  operation 
of  the  filters,  nor  in  the  bacteriological  results  from  the  filtrate, 
can  any  objection  be  found. 

"The  imperviousness  of  the  filters  and  embankments  in  the 
more  or  less  sandy  soil  of  the  Kalte  Hofe  was  obtained  in  the  fol- 
lowing manner  :  — 

"  Upon  a  layer  of  good  marsh  soil,  14  inches  thick,  was  placed 
a  layer  of  plastic  clay  puddle  4  inches  thick.  The  clay  was  pre- 
pared either  by  ordinary  clay-cutters,  or  by  grinding  in  pug  mills, 
such  as  are  used  in  the  manufacture  of  tile  and  brick.  The  bot- 
tom was  paved  with  bricks  laid  flatwise  in  cement  mortar,  while 
the  inner  slopes  were  paved  with  a  layer  of  bricks  on  edge.  The 
upper  edge  of  the  slope  paving  was  finished  with  a  strip  of  con- 
crete. The  outer  slopes  of  the  embankments  were  sodded.  The 
embankments  between 
the  filters  were  finished 
with  a  gravel  path,  in 
the  middle  of  which  the 
narrow  gauge  railway 
tracks  for  the  sand  cars 
were  laid. 

"After  the  water  has 
percolated  through  the 
sand  and  gravel  to  the 
bottom  of  the  filters,  it 
is  received  in  collecting- 
drains,  constructed  as 

shown  by  Fig.  14.  The  main  collecting-drain,  which  extends  from 
the  effluent  chamber  of  the  filter,  is  built  upon  a  separate  founda- 
tion in  the  filter-bed.  It  is  22  inches  high,  32  inches  wide  in  the 
clear,  with  brick  side  walls,  and  cover  stones  of  granite.  Into  this 
the  side  drains,  7.5  inches  high  and  6  inches  wide,  are  connected. 


—      Wafer 


Sand 


:* 


Z  Meters. 

1  '6'   )'  z'  V  4-'   5'  <&'  V  8'  &'  \0' 

Fig.  14.    Section  of  Main  Drain  and  Filtering  Materials, 

Hamburg,  Ger. 


212 


THE   PURIFICATION  OF   WATER. 


"The  branch  collecting-drains  of  brick,  laid  dry,  are  entirely 
surrounded  by  gravel.  The  top  of  the  granite  slabs  on  the  main 
drain  projects  into  the  sand  about  4  inches.  The  water  which 
collects  in  the  gravel  layer  either  flows  directly  into  the  main 
collector,  through  openings  in  the  brick  side  walls,  or  enters  the 
branch  collectors  through  similar  openings,  and  then  flows  to  the 
main  collector.  From  the  main  collector  the  clear  water  enters 
the  effluent  well  shown  in  Fig.  15. 

"The  arrangement  of  the  filtering  materials  is  shown  by  Fig. 
14.  The  water  stands  in  the  filter  at  about  3.6  feet  above  the 


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20'  40'  60'   ao'   100'      «0' 
Fig.  15.    Plan  of  Filters,  Hamburg,  Ger. 

sand,  and  must  penetrate  a  thickness  of  3.28  feet  (one  meter)  of 
fine  sand,  when  the  filter  is  first  put  in  operation,  which,  upon 
successive  parings,  may  be  diminished  to  a  thickness  of  16  inches. 
The  dirty  sand  is  scraped  off  in  successive  thicknesses  of  three- 
eighths  to  one-half  inch,  and  conveyed  to  the  sand  washer  to  be 
cleaned,  and  then  takes  its  place  again  in  the  filter.  The  layer 
of  sand  rests  upon  a  layer  of  gravel  24  inches  thick,  the  sizes  of 
which  are  so  arranged  that  the  upper  finer  material  cannot  pene- 
trate the  lower  coarser  material,  and  the  latter  cannot  enter  the 
collecting-drains. 


HAMBURG   SETTLING-BASINS  AND   FILTERS.  213 

ARRANGEMENT   OF    FILTERING   MATERIALS. 

„.  .    <  Effective  size,  0.30-0.34  mm.  r     . 

Fine  sand   \  _  ^40  inches. 


(  Uniformity  coefficient,  2.0  -2.3 
Gravel,  different  sizes,  24       " 

Total  depth  of  filtering  materials,  64  inches. 

Head  of  water  on  filter,  42       " 

"To  clean  the  filtering  materials  after  these  were  brought  from 
the  various  natural  deposits,  five  sand-washing  machines  were 
erected  at  different  points  on  the  work. 

"  The  gravel  which  was  taken  from  the  pits  had  to  be  freed 
from  the  mud  and  sand  attached  to  it,  and  also  assorted  into  the 
various  sizes  corresponding  to  the  layers  in  the  filters.  This 
double  object  is  accomplished  by  means  of  slightly  inclined  cylin- 
drical iron  drums,  having  numerous  projections  on  the  interior. 
The  gravel  being  placed  at  the  upper  end,  the  drum  is  revolved, 
while  numerous  jets  of  water  are  played  upon  the  material.  At 
the  lower  end  are  placed  a  number  of  shaking  sieves  of  various 
degrees  of  fineness,  one  above  the  other,  by  which  the  gravel  is 
separated  according  to  the  commercial  sizes,  and  then  falls  into 
wagons  placed  under  the  sieves. 

"  The  sand  is  taken  from  pits  and  banks.  Cylindrical  iron  drums 
were  also  used  for  the  purpose  of  cleaning  the  sand,  arranged  in 
such  a  way  that  of  the  raw  material,  when  threwn  upon  a  shaking 
sieve,  the  finer  particles  were  washed  through  this  sieve,  leaving 
the  coarser  material  upon  it.  It  was  then  introduced  into  the  lower 
end  of  the  slightly  inclined,  slowly  revolving  drum  (see  Fig.  29). 

"  By  means  of  a  number  of  spiral  vanes  upon  the  inside  of  the 
drum,  with  small  intervening  spaces,  the  mixture  of  sand  and  water 
was  conveyed  to  the  upper  end  of  the  drum,  where  it  was  dis- 
charged into  a  hopper.  As  the  sand  left  the  drum  it  was  again 
played  upon  by  a  strong  stream  of  water,  which  was  directed 
partly  into  the  interior  of  the  drum,  and  partly  on  the  sand  which 
was  flowing  out. 

"  By  this  arrangement  the  sand  gradually  came  in  contact  with 
cleaner  water  as  it  rose  to  the  upper  end  of  the  drum,  while  the  foul 
water  found  an  exit  from  the  lower  end  of  the  drum.  The  washed 
sand  was  then  shoveled  into  dump  cars  and  conveyed  to  the  filters. 


214  THE   PURIFICATION  OF   WATER. 

The  small  gravel  obtained  upon  separation  and  grading  of  the  sand 
was  washed,  and  used  as  the  top  layer  of  gravel  in  the  filters. 

During  a  day  and  night  turn  of  the  washing  apparatus,  the  fil- 
tering material  prepared  for  use  was  about  2,614  cubic  yards,  for 
which  were  required  :  — 

8  drums  worked  on  stone  and  coarse  gravel. 
4  drums  worked  on  smaller  gravel. 
26  drums  worked  on  sand. 

The  total  quantity  required  (for  eighteen  filters)  amounted,  in 
round  numbers,  to  104,640  cubic  yards  of  gravel  and  stone,  and 
248,520  cubic  yards  of  sand.  For  the  cleaning  of  the  stone, 
gravel  and  sand,  filtered  water  was  used  exclusively,  except  for 
the  materials  which  were  placed  in  the  first  filter,  for  which,  of 
course,  filtered  water  was  not  then  available. 

"  The  regulation  of  the  quantity  of  water  flowing  from  the  fil- 
ters is  accomplished  in  the  following  manner.  The  effluent  well 
contains  several  compartments,  through  which  the  water  must  pass 
successively.  From  the  main  collecting-drain,  the  water  enters 
the  first  compartment,  and  rises  to  an  elevation  corresponding  to 
the  elevation  of  the  raw  water  on  the  filter.  The  water  passes 
from  the  first  into  the  second  compartment  over  an  adjustable 
weir,  by  means  of  which  the  quantity  flowing  from  the  filters  will 
always  be  the  same.  The  dimensions  of  the  weir  are  such  that 
the  lower  edge  can  be  placed  at  a  point  2.30  feet  below  the  water 
level  of  the  filter.  When  the  weir  is  at  its  highest  position  the 
flow  of  water  is  checked  entirely,  and  the  filter  is  taken  out  of 
service  (see  Fig.  16). 

"One  attendant  can  regulate  the  position  of  the  weirs,  and 
serve  ten  filters  if  necessary.  To  the  weir  is  fastened  a  scale,  and 
a  float  placed  about  three  feet  to  the  rear  of  the  weir  operates  a 
pointer  which  indicates  on  the  scale  the  difference  in  height  of 
the  water  levels.  The  float  is  placed  to  the  rear  of  the  chamber 
to  avoid  the  influence  of  the  currents  of  water  flowing  over  the 
regulating  weir. 

"When  the  difference  of  height  is  constant,  i.e.,  when  the 
pointer  covers  a  certain  mark  on  the  scale  corresponding  to  the 


HAMBURG  SETTLING-BASINS  AND   FILTERS. 


215 


quantity   of   water   which   the   filter  was  in- 
tended to  yield,  the  flow  over  the  weir  will 
be     uniform    for    equal     intervals    of    time. 
Thus,  if  the  rate  of  percola- 
tion   through    the    sand    be 
2.56  inches  per  hour,  we  can 
deduce  the  height  from   the 
formula,    Q  =  a.  b.  h. 


in   which   b  —  1.0    m.  :   g  = 
9.81    m.,    the    coefficient,    a, 
being    obtained    from    obser- 
vation of  the  fall  of  the  un- 
filtered   water  when    the    supply   valve    was 
closed.     The  term  a  was  deduced  as  0.503, 
and  the  quantity  of  water   per   second 
was  observed  to  be  0.136  c.  m.,  and  (usin 
7,650  sq.  m.  as  the  useful  area  of  a  filter), 
we  obtain  h  =  0.155  m. 

"  It  was  intended  to  measure  the  quan- 
tity of  filtrate  by  the  difference  in  height 
between  the  water  levels  of  the  two  well 
chambers  separated  by  the  weir,  and  to  regis- 
ter this  difference  in  height  by  an  automatic 
apparatus,  but  attempts  in  this  direction  have 
not  given  satisfactory  results. 

"  From  the  second  of  the  well  chambers 
the  water  passes  through  an 
iron  pipe  into  a  third  com- 
partment, and  from  this  into  a 
branch  canal  2.624  feet  wide, 
and  then  to  its  respective 
branch  clear-water  conduit. 

"  In  determining  the  size 
of  the  filter  works,  a  velocity 
of  filtration  of  2.5  inches  per  hour,  or  5  feet 
per  day  vertical,    has   been   used  as  a  basis 
(this  is  a  measure  of  the  quantity  of  water 


216 


THE  PURIFICATION  OF   WATER. 


leaving  the  filter  when  the  influent  valve  is  closed)  ;  and  in  opera- 
tion the  attempt  is  made  to  not  exceed  this  rate  of  percolation, 
and  to  avoid  rapid  changes  in  the  rate  of  filtration.  But  variations 
in  consumption  (as  between  holidays  and  week-days,  or  between 
a  warmer  and  a  colder  day)  can  Le  compensated  by  a  temporary 
increase  in  the  rate  of  filtration,  as  it  will  scarcely  be  possible  to 
have  (at  Hamburg)  clear-water  reservoirs  of  such  size  as  will  pro- 
vide for  large  hourly  variations  in  the  demands  for  water. 

It  has  not  been  proven  by  the  experience  with  the  Hamburg 
filters  to  the  present  time  that  the  filtrate  is  affected  by  such 
variations  in  the  rate.*  In  fact,  the  daily  records  of  the  operation 
of  the  various  filters  indicate  that,  under  certain  circumstances, 
there  is  no  increase  in  the  numbers  of  bacteria  in  the  water  when 
the  rate  is  changing. 

The  two  following  diagrams  for  Filters  Nos.  12  and  16,  which 
have  been  compiled  from  the  daily  records  of  the  Hamburg  Hy- 
gienic Institute,  indicate  the  influence  of  changes  in  the  rate  of 
filtration,  on  the  bacterial  contents  of  the  filtered  water. 


k 


2,000,000 


1,000,000 


Filter  No.\2. 
Fig.  17.    Diagram  Showing  Operation  of  Filter  No.  12,  Hamburg,  Ger. 

Filter  No.  12  was  started  in  service  Dec.  12,  1893,  and  stopped 
for  scraping  of  the  sand  Jan.  27,  1894,  having  run  without  inter- 
ruption for  47  days.  Filter  No.  16  was  started  Dec.  6,  1893,  and 
stopped  Jan.  25, 1894,  having  run  without  interruption  for  51  days. 

*  April,  1897. 


HAMBURG  SETTLING-BASINS  AND  FILTERS. 


217 


These  two  diagrams  are  an  interesting  study  of  the  operation 
of  plain  sand  filters  on  a  large  scale.  Referring  to  that  for  Filter 
No.  12,  it  will  be  noted  that  the  rate  of  filtration  was  1,689,096 
gallons  per  acre  per  day,  for  the  first  24  days.  On  the  25th  day, 
the  rate  was  1,900,224  gallons  per  acre,  for  the  26th  day,  1,951,972 
gallons,  and  on  the  next  day  it  was  again  1,689,096  gallons  per 
acre ;  after  which,  to  the  47th  day,  the  rate  varied  from  1,329,379 
gallons  to  1,900,224  gallons  per  acre  per  day. 

During  this  interval  of  time  the  bacteria  per  cubic  centimeter 
ranged  from  23  colonies  on  the  44th  day,  to  93  colonies  on  the 
17th  and  19th  days  ;  never  reaching  the  limit  assigned  by  the 


K- December  1893. ->!< January  1&94. -X 


2,000,000 


1,000,000 


Filter  No.  1 6. 
Fig.  18.     Diagram  Showing  Operation  of  Filter  No.  16,  Hamburg,  Ger. 

German  Imperial  Institute  of  Hygiene  (100  colonies  per  cubic 
centimeter  of  the  filtrate),  and  averaging,  for  the  whole  time 
the  filter  was  in  service,  47  colonies  per  cubic  centimeter  of  the 
filtered  water. 

Filter  No.  16  was  operated  for  a  period  of  30  days  at  the  rate 
of  1,689,096  gallons  per  acre  per  day,  then  for  one  day  at  the 
rate  of  1,900,224  gallons  per  acre  per  day,  then  for  one  day  at 
the  rate  of  1,951,972  gallons,  and  for  the  next  two  days  at  the 
standard  rate  of  1,689,096  gallons  per  acre  per  day  ;  after  which, 
for  the  remainder  of  the  period  of  51  days,  the  rate  varied  from 
1,329,379  gallons  to  1,900,224  gallons  per  acre  per  day. 

For  the  51  days  of  service  of  the  filter,  the  bacteria  per  cubic 


218 


THE   PURIFICATION  OF   WATER. 


centimeter  of  filtrate  varied  from  55  colonies  on  the  2d  day  of 
service  to  6  colonies  on  the  25th  day,  the  average  for  the  whole 
time  being  21  bacteria  per  cubic  centimeter  of  filtrate. 

The  general   bacterial   efficiency  of    the    Hamburg    filters    is 
shown  by  the  following  table  :  — 


SOURCE  OF  SAMPLE. 

BACTERIA  PER  C.  C.  OF  WATER. 

Unfiltered  water  from  the  Elbe, 
From  the  filters, 
Average  bacterial  reduction,  per  cent, 

800-3000 

20-    30 

98.64 

Whenever  a  filter  has  reached  a  point  in  its  periodical  "  run  " 
where  it  requires  a  head  of  water  on  the  sand  in  excess  of  the 
maximum  allowed,  viz.,  42-44  inches,  in  order  to  obtain  the 
standard  rate  of  delivery,  it  is  taken  out  of  service,  the  sand 
scraped,  and  after  observing  the  usual  precautions  in  refilling,  is 
started  again. 

At  Hamburg  the  drainage  pipes  of  the  filters  are  20  inches 
diameter,  and  controlled  by  an  ordinary  stop  valve.  All  the  drain- 
age pipes  discharge  into  a  common  masonry  conduit  or  sewer  about 
4  feet  diameter,  which  traverses  the  Kalte  Hofe,  and  connects  with 
a  pump  well  on  the  bank  of  the  River  Elbe. 

(Mr.  Meyer  is  silent  upon  the  manner  of  discharging  the 
contents  of  this  pump-well.  Water  drawn  from  the  bottom  of  a 
filter  after  it  is  taken  out  of '  service  will  be  filtered  water,  and  if 
not  changed  in  quality  in  passing  through  the  drainage  conduit, 
could  with  safety  be  pumped  into  the  clear-water  conduit  which 
conveys  the  water  from  the  filters  to  the  clear-water  basin  at 
Rothenburgsort.  The  first  run  of  a  filter  after  it  is  started  in 
operation  is  probably  also  discharged  into  this  same  drainage  con- 
duit or  sewer,  and  collected  finally  in  the  same  pump-well,  from 
which  it  should  be  pumped  into  the  river.  The  double  use  of 
this  drainage  conduit  is  open  to  criticism.  In  one  aspect  of  the 
case  it  indicates  the  waste  of  filtered  water  which  might,  with  a 
proper  arrangement  of  pipes  or  conduits,  be  saved  and  used ;  and 
in  another,  the  possible  after  pollution  of  water  which  had  left 
the  filter  in  condition  for  domestic  use.) 


HAMBURG  SETTLING-BASINS  AND  FILTERS.  219 

0 

To  refill  and  start  a  filter,  water  from  the  clear-water  conduit 
is  allowed  to  flow  backward  through  sluice  gates  in  the  effluent 
well  to  the  central  collecting-drain,  from  this  to  the  lateral  brick 
drains,  and  finally  upward  through  the  gravel  and  sand  until  it 
stands  at  a  depth  of  eight  inches  above  the  surface  of  the  sand. 
Further  filling  is  then  accomplished  by  opening  the  valve  in  the 
influent  chamber,  after  which  the  automatic  float  and  valve  in  this 
chamber,  in  connection  with  the  adjustable  weir  in  the  effluent 
chamber,  regulates  the  head  on  the  sand  and  the  discharge  of  the 
filter,  within  the  limits  fixed  in  practice. 

Each  filter  is  connected  with  a  clear-water  conduit  of  brick 
masonry  8.5  feet  diameter,  2,460  feet  long,  which  lies  parallel  to 
the  dike  of  the  Elbe.  This  conduit  at  one  point  is  connected  with 
the  old  conduit  through  which  the  water  was  taken  from  the  river 
for  the  old  settling-basins  prior  to  May,  1893.  The  connection 
was  made  by  means  of  a  side-shaft,  and  so  arranged  that,  during 
the  construction  of  the  filters,  each  filter  could  be  allowed  to  dis- 
charge its  filtrate  into  the  old  conduit ;  and  after  a  sufficient  num- 
ber of  filters  were  put  in  service  to  supply  the  whole  quantity  of 
water  consumed  by  the  city,  the  connection  between  the  old 
intake  from  the  river  and  the  new  filtered-water  conduit  was  tem- 
porarily closed.  During  September  of  1893,  a  leak  was  discovered 
in  the  temporary  bulkhead,  and  the  connection  between  the  old  and 
new  conduits  was  closed  with  a  permanent  bulkhead  of  concrete. 

From  the  clear-water  conduit  on  the  Kalte  Hofe,  the  water  is 
carried  by  an  inverted  siphon  of  welded  steel  pipe  6.56  feet  dia- 
meter, across  the  Billwarder  Bay,  to  a  basin  or  clear-water  reservoir 
on  the  Rothenburgsort,  from  which  the  filtered  water  is  pumped 
to  the  city. 

The  clear-water  basin  is  covered  with  a  masonry  vaulting  rest- 
ing on  pillars,  the  arches  of  which  are  coated  with  a  layer  of 
asphalt,  to  exclude  the  water  which  may  percolate  through  the 
earth  and  sand  which  is  placed  above  the  arches,  and  the  whole 
covering  is  finally  finished  with  a  layer  of  sod.  Drain  tile  is 
placed  over  the  arches,  to  carry  off  the  seep  water  which  may  find 
its  way  through  the  covering. 

The  capacity  of  the  clear- water  basin  (1897)  is  stated  to  be 


220  THE  PURIFICATION  OF   WATER. 

6,182,280  U.  S.  gallons,  while  the  average  daily  consumption  of 
water  for  1896  is  given  as  31,524,080  gallons,  indicating  that  this 
clear-water  reservoir  was  filled  and  emptied  about  five  times  each 
day.  The  maximum  daily  consumption  for  1896  was  38,407,811 
gallons,  at  which  time  the  clear-water  basin  contained  less  than 
four  hours'  average  consumption.  The  author  is  informed  that, 
during  the  summer,  the  temperature  of  the  water  falls  about  2° 
Fahr.,  between  the  river  and  the  clear-water  reservoir,  while  in 
the  winter  the  temperature  rises  between  these  two  points  about 
the  same  amount. 

The  average  length  of  "  run  "  of  a  filter  between  scrapings, 
at  Hamburg,  is  about  forty  days.  But,  as  the  author  is  informed, 
under  favorable  conditions  of  the  water  from  the  river,  during  the 
winter  of  1896-1897,  one  filter  successfully  delivered,  between 
scrapings  of  the  sand,  a  column  of  water  105  m.  (344.5  feet) 
high,  which  is  equivalent  to  112,215,438  U.  S.  gallons  per  acre,  or 
at  the  standard  rate  of  percolation  for  these  filters  (1,689,096  gal- 
lons per  acre  per  day),  represents  an  uninterrupted  service  for  66 
days. 

The  average  daily  per  capita  consumption  of  water  by  Ham- 
burg for  1896  was  50  U.  S.  gallons. 

THE    SCHRODER    SAND-WASHER. 

The  sand-washers  now  in  use  at  the  Hamburg  Water-Works 
are  the  invention  of  Mr.  Rud  Schroder,  inspector  of  the  filters ;  and 
each  set  consists  of  seven  conical  boxes  or  hoppers  of  iron  or  steel, 
in  the  lower  ends  of  which  are  fitted  Korting  ejectors.  Filtered 
water  under  a  head  of  thirty-six  feet  is  supplied  to  the  ejectors 
from  a  manifold,  while  the  sand  is  fed  into  the  first  hopper  by 
manual  labor.  The  mixture  of  sand  and  water  is  carried  up 
through  a  vertical  pipe  by  the  action  of  the  ejector,  and  dis- 
charged into  the  next  hopper  of  the  series.  The  current  of  water 
through  the  ejector  performs  two  offices;  one,  the  transportation 
of  the  sand  from  hopper  to  hopper,  and  the  other,  the  separation 
and  washing  of  the  dirty  sand.  The  dirty  wash-water  overflows 
the  upper  edges  of  the  hopper,  and  is  carried  off  by  suitable 


HAMBURG  SETTLING-BASINS  AND  FILTERS. 


221 


troughs.  Seven  hoppers  of  the  form  shown  in  the  drawing  (Figs. 
19  and  20)  are  found  sufficient  to  effectually  wash  the  sand 
scraped  from  the  filters,  and  restore  it  to  a  condition  fit  to  go 
into  the  filters  again. 

From  the  vertical  pipe  in  each  hopper  a  trough  conveys  the 
mixture  of  sand  and  water  to  the  next  hopper  of  the  series.  By 
Fig.  22,  it  will  be  seen  that  these  ejector  washers  are  arranged  in 
sets  of  two,  each  set  consisting  of  a  sand-chute,  a  small  receiving- 

Sand-Washing  Plant,  Hamburg,  Ger. 


Fig.  19  (Hopper  No.  7). 


Fig.  20  (Hopper  No.  2). 


hopper  at  the  bottom  of  the  sand-chute,  and  six  larger  elevated 
hoppers.  From  the  last  hopper  the  washed  sand  is  discharged 
onto  a  platform,  from  which  it  is  shoveled  into  the  tram-cars. 
The  surplus  water  from  the  sand  is  conveyed  away  by  troughs  to 
the  rear  of  the  platform. 

These  hoppers  are  about  2  feet  6  inches  square,  excepting  the 
first  of  the  series,  which  is  2  feet  square.  The  first  hopper  which 
receives  the  sand  is  about  1  foot  8  inches  deep,  while  the  remain- 
ing hoppers  are  about  2  feet  2  inches  deep.  The  converging 
chute  into  which  the  "  fouled  "  sand  is  dumped  is  4  feet  2  inches 


222 


THE  PURIFICATION  OF   WATER. 


Fig.  Z4. 
Transverse  Section  C— D 


Sand-Washing  Plant,  Hamburg,  Ger. 


HAMBURG  SETTLING-BASINS  AND   FILTERS.  223 

• 

by  6  feet  6  inches  at  the  top,  and  4  feet  deep.  This  is  provided 
with  a  gate  and  screen  at  the  bottom,  through  which  the  flow  of 
sand  to  the  first  of  the  washing-hoppers  is  regulated.  The  water- 
pipe  from  the  manifold  to  the  ejector  is  \\  inches  diameter,  and 
the  elevator  pipe  above  the  ejector  is  3  inches  diameter.  A  chilled 
iron  throat  is  screwed  into  the  lower  end  of  the  elevator  pipe  to 
resist  the  grinding  action  of  the  mixture  of  sand  and  water. 

From  Mr.  Schroder's  description  of  this  apparatus,*  as  used 
with  the  Hamburg  filters,  one  complete  set  of  washers  and  all 
appurtenances  cost  about  $2,400.  Four  sets  of  washers  are  suffi- 
cient for  the  service  of  18  filters  of  1.89  acres  each,  or  34  acres  of 
filtering  area.  The  expenditure  of  water  per  cubic  yard  of  sand 
washed  averages  4,043  U.  S.  gallons,  applied  under  a  head  of  36 
feet.  As  stated  before,  filtered  water  only  is  used  for  sand-wash- 
ing. This  style  of  washer  is  regarded  at  Hamburg  as  being  more 
economical  in  labor  than  the  drum  washers  employed  at  Berlin 
and  in  the  London  Water-Works,  although  requiring  about  twice 
the  quantity  of  water  for  washing  the  sand  and  operating  the 
ejectors. 

The  capacity  of  one  set  of  the  Hamburg  sand-washers  is 
stated  by  Mr.  Schroder  to  be  4  c.  m.,  or  5.23  cubic  yards,  of  sand 
cleaned  per  hour.  The  author  is  informed  that  these  ejector  sand- 
washers  have  been  in  constant  service  since  1894,  cleaning  annu- 
ally about  25,000  c.  m.  (32,675  cubic  yards)  of  "fouled  "  sand  from 
the  filters,  and  have  during  this  time  given  entire  satisfaction. 

The  following  notes  are  from  the  operation  of  these  Water- 
Works  for  1896  :  - 

Total  consumption  of  water  for  all  purposes,  11,506,300,000  U.  S.  gallons. 
Consumed  in  washing  sand  from  filters,  91,800,000  U.  S.  gallons. 
Percentage  of  filtered  water  required  by  the  Schroder  sand-washers,  0.80. 

(In  Chap.  XVII.  it  will  be  noted  that  the  English  type  of  sand- 
washers,  in  use  at  Berlin,  and  formerly  used  at  Hamburg,  require 
about  T4o  of  one  per  cent  of  the  filtered  water  for  washing  the 
"fouled"  sand  scraped  from  the  filters.) 

*  Zeitschrift  des  Vereines  Deutscher  Ingenieure,  vol.  xxxix.,  Hamburg,  1894. 


224 


THE   PURIFICATION  OF   WATER. 


THE    MAGER    SAND-SCRAPING    DEVICE. 

The  winters  of  Hamburg  have  been  sufficiently  rigorous  since 
the  filters  were  started  in  service  to  produce  some  inconvenience 
in  the  scraping  of  the  sand-beds  after  the  ice  forms  on  the  water, 
which  has  occurred  as  early  as  November,  and  continued  until  late 
in  February.  The  following  diagram,  from  the  records  of  the 
Hamburg  Water- Works,  illustrates  the  time  of  formation,  duration 
and  thickness  of  the  ice-cover  over  the  niters,  during  the  winter 
of  1896-1897. 


,   1696 ->*• r 1897 

Nov.  — ->|< December- >j<- -  January  >K -February > 

.  Zl    26     11      6     II      18     21     26    311     6      II      16     7>f    26    3l'l      6      II      16     21     26 


Fig.  25.     Diagram  Showing  Ice  on  Filters,  Winter  of  1896-1897,  Hamburg,  Ger. 

From  this  diagram  it  will  be  seen  that  the  ice  began  to  form 
on  the  filters  Nov.  23,  1896,  and  continued  until  Feb.  27,  1897, 
attaining  a  thickness  of  about  13  inches.  During  this  time  sev- 
eral of  the  filters  in  service  were  cleaned  by  the  Mager  apparatus, 
to  be  described. 

Before  the  invention  of  the  Mager  sand-scraping  apparatus  the 
filter-beds  were  cleaned  by  hand-dredging  from  the  after  end  of  a 
scow,  which  was  slowly  moved  across  the  water  from  side  to  side 
of  a  filter,  by  means  of  a  wire  rope  stretched  from  bank  to  bank, 
which  engaged  with  a  whim  or  capstan  mounted  on  the  scow.  In 
order  to  conduct  the  work  in  this  manner,  it  was  necessary  to  first 
cut  away  or  break  and  remove  the  ice  from  that  portion  of  the 
water  where  the  traverse  of  the  scow  and  scrapers  was  to  be  made. 
The  scrapers  were  mounted  on  long  poles,  and  provided  with  bags 
or  other  receptacles  for  the  sand  scraped  from  the  surface  of  the 


HAMBURG  SETTLING-BASINS  AND   FILTERS.  225 

bed.  As  rapidly  as  these  receptacles  were  loaded,  the  scow  was 
stopped,  the  scrapers  and  accumulation  of  "fouled"  sand  lifted  on 
board  and  dumped.  The  scrapers  were  then  put  in  position  again, 
and  the  motion  of  the  scow  resumed  across  the  filter. 

The  traverse  of  the  scow  and  hand-scrapers  was  from  side  to 
side  of  the  filter,  reversing  the  position  of  the  scrapers  with  each 
traverse,  and  shifting  the  position  of  the  wire  rope  a  distance  equal 
to  the  width  of  the  swath  or  path  scraped  during  the  preceding 
traverse. 

The  hand  scrapers  were  always  worked  from  the  after  end  of 
the  scow,  and  upon  accumulating  on  board  a  load  of  "  fouled " 
sand,  this  was  wheeled  to  the  bank,  and  carried  to  the  sand- 
washers. 


Fig.  26.    Device  for  Scraping  Ice-Covered  Sand-Filters,  Hamburg,  Ger. 

By  successive  traverses  from  slope  to  slope  the  whole  area  of 
the  sand-bed  was  scraped,  and  the  filter  restored  to  service. 

The  use  of  this  apparatus  required  the  breaking  of  the  ice  over 
the  whole  water  area,  and  involved  an  expense  of  labor  and  time 
which  brought  about  the  invention  of  the  apparatus  shown  in 
Fig.  26. 

The  Mager  device  consists  of  a  large  float  which  impinges 
against  the  under  side  of  the  ice  cake,  and  a  metal  scraper  hung 
from  the  float  by  a  pair  of  oscillating  arms.  Two  chains,  con- 
nected to  the  scraper  and  the  float,  limit  the  oscillation  of  the 
arms,  and  with  reference  to  the  float,  regulate  the  depth  of  the 
swath  cut  in  the  surface  of  the  sand.  To  the  scraper  is  attached 
a  bag  which  receives  the  "fouled"  sand  as  it  is  cut  from  the  sur- 


226  THE   PURIFICATION  OF   WATER. 

face  of  the  bed.  The  float  and  scraper  is  introduced  at  one  end 
of  the  filter  under  the  ice,  and  by  means  of  two  capstans,  placed 
one  upon  each  of  the  two  longer  embankments  of  the  filter,  and 
two  wire  ropes  attached  to  the  float,  the  float  and  scraper  is 
dragged  from  side  to  side  of  the  filter  without  removing  or  break- 
ing the  ice-cover. 

When  the  scraper  has  made  a  full  traverse  across  the  filter,  by 
pulling  upon  one  of  the  two  lines  connected  with  the  sand-bag,  it 
is  turned  inside  out  like  a  stocking,  and  the  contents  emptied  on 
the  inner  slope  of  the  embankment.  Upon  traversing  the  filter  in 
the  opposite  direction,  the  scraper  is  reversed,  and  upon  reaching 
the  further  slope  the  sand  is  discharged  by  pulling  upon  the  other 
line  and  reversing  the  bag.  In  this  manner  the  float  and  scraper 
is  drawn  from  side  to  side  of  the  filter  until  the  whole  bed  of  sand 
is  scraped,  the  "  fouled  "  sand  being  left  upon  the  slopes  or  at  the 
edge  of  the  sand-bed. 

As  each  traverse  is  made,  the  capstans  on  the  embankments 
are  moved  along  the  filter  a  distance  equal  to  the  width  of  the 
swath  cut  in  the  sand  by  the  previous  traverse  of  the  scraper. 

This  apparatus  requires  only  the  cutting  away  of  a  narrow  strip 
of  ice  at  each  end  of  the  filter,  and  at  the  side  slopes,  for  the  intro- 
duction and  removal  of  the  float  and  scraper,  for  the  operation  of 
the  wire  cables  which  drag  the  float  under  the  ice  from  side  to 
side  of  the  filter,  and  for  handling  the  lines  which  reverse  the 
sand-bag  and  discharge  its  contents. 

A  comparison  of  the  time  required  to  scrape  the  sand-bed  with 
the  scow  and  hand  scrapers,  with  the  time  required  by  the  Mager 
float  and  scraper,  indicates  a  reduced  cost  of  labor  for  the  latter ;  and 
a  comparison  of  the  after  periods  which  the  filter  will  run,  and  the 
volumes  of  water  delivered  before  a  new  scraping  is  required,  in- 
dicates a  gain  in  the  efficiency  of  the  filter  ;  i.e.,  the  periods  of  sub- 
sequent operation  are  longer,  and  the  quantities  of  water  delivered 
by  the  filter  are  greater,  than  with  the  apparatus  previously  in  use. 

From  tables  in  a  paper  by  Mr.  E.  Mager,  descriptive  of  this 
apparatus,*  the  following  data  are  derived  :  — 

*  Process  of  Cleaning  the  Open  Filters  of  the  Hamburg  Water-Works  During  the  Winter. 
By  Ed.  Mager,  Engineer,  Hamburg,  1897,  pp.  4,  6. 


HAMBURG  SETTLING-BASINS  AND   FILTERS.  227 


.  BY  THE   OLD   METHOD   OF   SAND-SCRAPING. 

Average  time  required  to  clean  one  filter,  4.3  days. 

Least  "       "       "       "  3          « 

Greatest    «          "          "       "       "       "  7          « 

Generally  4  days  were  sufficient  to  scrape  the 

sand  from  a  bed  of  1.89  acres  area. 
Average  length  of  time  the  filters  were  in  ser- 

vice after  scraping,  15          " 

Least  time  the  filters  were  in  service  after 

scraping,  4.0       " 

Greatest  time  the  filters  were  in  service  after 

scraping,  29.0        " 

Generally  the  filters  were  in  service  after  scrap- 

ing, 17.4       « 

Average  yield  of  (one)   filter  after  scraping,  28,493,336  U.  S.  gallons. 
Least  yield,  7,040,402 

Greatest  yield,  48,725,085       «         « 

Generally  the  average  yield  after  scraping  the 

sand  was,  33,588,010       «         « 

Upon  a  second  scraping  of  one  filter  by  the  former  process, 
6  days  were  required  to  remove  the  "  fouled  "  sand,  after  which  the 
filter  was  in  service  for  only  5  days,  and  the  yield  was  7,645,155 
gallons. 

With  the  Mager  apparatus  for  scraping  the  sand-bed  under  the 
ice,  the  average  time  required  for  the  cleaning  of  three  filters  was 
2.3  days  each.  The  average  period  of  operation  of  the  filters  was 
17  days,  and  the  yields  of  filtered  water  were  as  follows  :  — 

Average  yield,  38,774,256  U.  S.  gallons. 

Least          "  24,767,165      « 

Greatest     «  57,910,790      « 

Upon  a  second  cleaning,  one  of  the  filters  required  5  days  for 
scraping  the  sand,  with  an  after  operation  of  12  days,  and  a  yield 
of  19,235,873  gallons. 

Generally,  after  cleaning  the  sand-bed  with  the  Mager  apparatus, 
the  yield  of  filtered  water  is  from  one-third  to  one-half  as  much  as 
when  the  same  bed  is  laid  dry  and  scraped  with  shovels  in  the 
usual  way. 


228 


THE   PURIFICATION  OF   WATER. 


At  present  the  average  time  required  for  the  scraping  of  a  sand- 
bed  of  1.89  acres  with  the  Mager  apparatus  is  about  40  hours. 

Referring  to  the  diagram  (Fig.  25),  during  the  interval  of  time 
when  the  surface  of  the  water  on  the  niters  was  frozen,  niters  were 
cleaned  with  the  Mager  apparatus  as  follows  :  — 


NUMBER 

OF 

FILTER. 

DATE  OF 
SCRAPING. 

DURATION  OF 
AFTER  SERVICE. 
DAYS. 

NUMBER 

OF 

FILTER. 

DATE  OF 
SCRAPING. 

DURATION  OF 
AFTER  SERVICE. 
DAYS. 

7 

December  10, 

16 

January         1, 

7 

January      11, 

31 

16 

January      22, 

21 

7 

January      14, 

6 

January        9, 

7 

February    15, 

32 

6 

February    21, 

43 

8 

December  26, 

4 

January       16, 

8 

January      15, 

20 

4 

February      7, 

22 

8 

January      19, 

12 

January      22, 

8 

February      9, 

21 

12 

February    24, 

33 

Another  method  which  was  resorted  to  during  the  past  winter 
for  scraping  the  sand-bed  is  described  by  Mr.  Schroder.  The  ice 
was  cut  away  from  one-half  the  bed,  and  the  water  level  lowered 
until  the  ice-cake  rested  on  the  sand.  Workmen  were  then  put 
upon  the  dry  portion  of  the  bed,  and  removed  the  "fouled"  sand 
by  hand-scraping.  The  filter  was  then  filled  with  water,  the  ice- 
cake  floated  over  to  the  opposite  side,  and  the  water  again  lowered 
until  the  remaining  half  of  the  filter  was  laid  bare.  This  half  was 
then  scraped  by  hand  in  the  same  manner,  after  which  the  filter 
was  filled  and  put  in  regular  service.  An  operation  like  this  of 
course  requires  that  the  temperature  of  the  air  shall  be  above  the 
freezing-point  during  the  interval  of  time  when  the  water  is  off 
the  filter. 

About  the  first  week  of  November,  1897,  the  daily  newspapers 
of  the  United  States  contained  an  account  of  an  epidemic,  or  un- 
warranted increase,  of  typhoid  fever  in  Hamburg  during  the  fall 
of  that  year.  Desirous  of  ascertaining  if  this  was  caused  by  the 
failure  of  the  filters  to  properly  purify  the  raw  Elbe  water,  or  if 
the  increase  in  typhoid  was  traceable  to  other  causes,  the  author 
requested  an  explanation  of  the  Hamburg  officials  ;  and  from  the 
letter  in  reply  the  following  quotations  are  extracted  :  — 


HAMBURG   SETTLING-BASINS  AND   FILTERS.  229 

"  The  investigations  by  the  Medical  Board  *have  shown  that 
the  increase  in  typhoid  fever  during  the  fall  of  1897  was  due 
either  to  the  use  of  raw  milk  or  unfiltered  Elbe  water,  and  there 
was  no  evidence  to  show  any  connection  between  this  rise  in  the 
typhoid  rates  and  the  filtered  public  water  supply. 

"The  use  of  the  raw  water  for  drinking-purposes  is  partly  due 
to  the  following  facts  :  - 

"  For  a  time  after  our  epidemic  of  cholera  in  1892  (when  natu- 
rally the  people  had  a  dread  of  the  unfiltered  Elbe  water),  no  cases 
of  typhoid  occurred.  With  the  lapse  of  time,  this  fear  of  the  raw 
river  water  has  somewhat  subsided  ;  and  notwithstanding  the  warn- 
ing signs  set  up  at  frequent  intervals  along  the  harbor  against 
using  (for  drinking  or  dietetic  purposes)  the  unfiltered  river  water, 
some  people  associated  with  the  river  interests  are  reckless  enough 
to  use  this  water. 

"  Excepting  such  cases  as  were  due  to  raw  (unsterilized)  milk, 
it  may  therefore  be  of  interest  to  you  to  know  that  all  other  cases 
of  typhoid  fever  have  been  stated  by  our  Medical  Board  as  being 
derived  from  the  use  of  raw  river  water  in  the  harbor,  and  not 
from  the  use  of  our  filtered  water,  which  remains  up  to  date  of 
excellent  quality." 


230  THE   PURIFICATION  OF   WATER. 


CHAPTER   XIV. 

THE   FILTERS    OF   THE   BERLIN    WATER-WORKS. 

THE  original  filters  of  the  Berlin  Water- Works  at  the  Stralau 
station,  built  in  1855-1856,  were  uncovered,  and  as  described  by 
Mr.  Kirkwood,*  consisted  of  six  beds,  with  an  area  of  about  4.86 
acres,  or  0.81  acre  to  each  filter.  The  filtering  materials  consisted 
of  small  boulders,  gravel,  and  sand.  No  lateral  drains  were  used  to 
convey  the  filtered  water  to  the  central  drain,  the  boulders  at  the 
bottom  of  the  bed  performing  this  office. 

The  arrangement  of  the  filtering  materials  was  as  follows  :  — 

Fine  sand  at  top  of  bed  (effective  size,  0.35  mm.),  18  inches. 

Coarse  sand,  12       " 

Coarser  sand,  6       " 

Gravel  under  the  sand,  and  boulders  at  bottom  of  filter,       22       " 
Total  depth  of  filtering  materials,  58  inches. 

Depth  of  water  on  filters,  54-60       " 

According  to  Mr.  Kirkwood,  ice  from  15  to  20  inches  in  thick- 
ness had  formed  over  the  filters  during  "  long  and  severe  winters  ;  " 
and  as  a  protection  to  the  filter  walls,  the  ice-cake  was  broken 
around  the  edges  "  by  workmen  appointed  to  that  duty."  This 
difficulty  with  the  ice,  and  the  impossibility  at  that  time  of  properly 
cleaning  the  sand-beds  in  winter,  led  to  the  adoption  of  covered 
filters  in  the  Lake  Miiggel  Works,  to  be  described.  As  originally 
constructed,  the  filters  at  the  Stralau  station  were  open  ;  but  since 
1893  these  filters  have  been  covered. 

The  new  water-works  of  Berlin  are  located  on  the  north  shore 
of  Lake  Miiggel,f  a  branch  and  enlargement  of  the  River  Spree, 

*  Filtration  of  River  Waters,  by  J.  P.  Kirkwood,  1869,  p.  112. 

f  The  Filtration  of  the  Miiggel  Lake  Water  Supply,  Berlin,  by  Henry  Gill,  Institution  of 
Civil  Engineers,  London,  1895,  p.  14. 


THE   FILTERS  OF   THE  BERLIN   WATER-WORKS. 


231 


about  12  miles  from  the  center  of  the  city.  *Lake  Miiggel,  so- 
called,  is  2.90  miles  long  and  1.43  miles  wide,  with  a  depth  over 
the  greater  part  of  the  area  of  26£  feet. 


Unaltered  Water 
Inlet  Pipe 


Pilfered  Water 
Out-let  Pipe 

Washout  Pipe 


Fig.  27.    Plan  of  Filters  at  Lake  Miiggel,  Berlin,  Ger. 

The  works  are  designed  to  supply  47,280,000  gallons  of  water 
per  day,  and  contain  44  filters,  each  of  an  area  of  0.576  acres,. or  a 
total  sand  surface  of  25.344  acres,  divided  into  four  groups  of  11 


232  THE   PURIFICATION  OF   WATER. 

filters  each.  It  is  assumed  in  these  works  that  3  filters  of  each 
group  will  at  all  times  be  out  of  service  for  cleaning  and  renewal  of 
the  sand,  or  be  held  in  reserve ;  hence  T8T  of  the  total  filtering 
capacity  only  will  be  available.  The  estimated  rate  of  filtration 
is  2.448  gallons  per  square  foot  of  sand  surface  per  hour,  or 
2,559,237  gallons  per  acre  per  day.  The  available  filter  area  is 
assumed  to  be  18.432  acres,  and  the  daily  capacity  as  47,171,856 
gallons  per  day. 

The  filtering  materials  are  arranged  as  follows  :  — 

Fine  sand  at  top  of  bed  (effective  size,  0.35  mm.),  24  inches. 

Gravel,  12 

Boulders,  12       " 

Total  depth  of  filtering  materials,  48  inches. 

Head  of  water  on  filters,  maximum,  31.5       « 

Head  of  water  on  filters,  minimum,  3.6       " 

(Mr.  Gill  estimates  the  voids  or  water  space  in  the  compacted  sand  as 
J  of  the  whole  mass.) 

The  rate  of  discharge  from  a  filter  is  a  nearly  constant  quan- 
tity ;  and  to  effect  this  with  an  increasing  head  on  the  sand-bed,  the 
water  flows  from  the  effluent  chamber  to  the  clear-well  through  a 
submerged  orifice,  the  head  over  which  is  maintained  at  a  uniform 
height  by  the  adjustment  of  a  sluice  gate,  placed  in  the  division 
wall  of  the  effluent  chamber,  between  the  sluice  chamber  and  the 
weir  chamber.  The  adjustment  of  the  gate  from  day  to  day  serves 
to  maintain  the  difference  of  level  between  the  water  on  the  filter 
and  the  water  in  the  sluice  chamber,  to  obtain  the  desired  rate  of 
percolation  through  the  sand,  and  the  proper  head  on  the  sub- 
merged orifice  in  the  weir  chamber.  (See  Fig.  28.) 

By  this  device  (the  invention  of  Mr.  Gill)  any  variation  in  the 
demand  for  water  can  neither  increase  nor  diminish  the  rate  of 
flow  through  the  filters,  and  will  only  lower  or  raise  the  level  of 
water  in  the  clear-well. 

The  Muggel  filters  are  covered  with  groined  arches,  the  sup- 
porting piers  of  which  are  placed  14.37  feet  center  to  center  in 
each  direction.  At  the  center  of  each  arch  over  four  piers,  an 
opening  is  placed,  which  admits  of  a  thorough  lighting  up  of  the 
bed  of  sand  for  the  purpose  of  cleaning. 


THE   FILTERS   OF   THE   BERLIN   WATER-WORKS. 


233 


According  to  the  experience  at  Zurich,  the  cost  of  operating  is 
lower  for  the  closed  filters  than  for  the  open  filters,*  while  the  re- 
verse seems  to  be  true  at  Berlin  ;  for  the  closed  filters  are  said  to 
entail  a  cost  of  $10.00  f  per  million  U.  S.  gallons,  the  highest  cost 
for  any  European  filtration  works  from  which  reports  have  been 
obtained  by  the  author.  Aside  from  the  special  difficulties  due  to 
the  formation  of  ice  on  the  open  filters  in  climates  like  that  of  Ber- 
lin, the  cost  of  scraping,  removing,  and  renewing  the  sand  should 


Filter 


Showing  Level  of  Water 
in  Sluice  Chamber. 


Fig.  28.    Plan  of  Regulating  Chamber. 
(Gill  on  the  Filtration  of  the  Miiggel  Lake  Water-Supply.} 

be  the  least  with  open  filter-beds,  and  why  the  closed  filters  at  Zu- 
rich (after  omitting  the  charge  for  breaking  the  ice)  should  cost 
less  for  operating  than  the  open  filters,  requires  some  explanation. 
At  Berlin  the  clear-water  reservoir  is  also  covered  with  a 
masonry  vaulting;  and  the  whole  work,  as  described  by  Mr.  Gill, 
is  of  the  most  substantial  kind. 

*   Water  Supply  of  Ziirich,  Preller,  p.  37. 

f  Said  to  include  interest  and  sinking-fund  charges. 


234  THE   PURIFICATION  OF   WATER. 

The  new  water-works  at  Lake  Miiggel  were  planned  to  supply 
a  population  of  1,700,000  with  an  allowance  of  27.5  U.  S.  gallons 
per  capita,  which  would  indicate  an  approximate  present  pumpage 
and  filtration  of  46,750,000  U.  S.  gallons  of  water  per  diem. 

From  an  elaborate  description  by  the  late  Mr.  Henry  Gill  of  the 
method  for  operation  of  the  filters  at  Lake  Miiggel,  the  following 
resume  is  taken. 

The  filter  is  started  in  service  by  filling  from  below  with  filtered 
water.  The  water  is  allowed  to  percolate  slowly  upward  through 
the  bed  of  sand  in  order  to  displace  the  air  and  fill  all  the  voids 
between  the  sand-grains.  In  filling  a  filter  the  influent  and  efflu- 
ent gates  are  closed,  and  the  water  drawn  back  through  an  inde- 
pendent valve  and  pipe  from  the  clear-well.  As  soon  as  the  water 
has  risen  4  inches  above  the  bed  of  sand,  the  influent  gate  is 
opened,  and  further  filling  is  cautiously  conducted  with  unfiltered 
water.  After  a  head  of  1.6  feet  above  the  sand  has  been  attained, 
the  unfiltered  water  is  quickly  run  on  the  filter  until  the  full  ope- 
rating head  is  reached.  Mr.  Gill  recommends  that  a  filter  be  filled 
at  a  rate  of  not  more  than  4.7  inches  per  hour,  to  avoid  disturbance 
of  the  sand. 

After  a  filter  has  been  filled,  it  should  be  rested  with  the  water 
over  the  sand-bed  for  24  hours,  in  order  that  the  pores  of  the  sand- 
bed  may  be  partially  closed  by  sedimentation  ;  and  in  cases  when 
this  length  of  rest  is  inadmissible,  and  the  filter  must  be  put  in 
service  earlier  to  maintain  the  supply  of  filtered  water,  it  should 
be  brought  very  gradually  up  to  its  normal  work.* 

Sudden  variations  in  head  or  pressure  on  the  sand-bed  should 
be  avoided,  to  prevent  injury  to  the  film  of  silt  and  the  products 
of  bacterial  action  at  the  surface  of  the  sand.  After  the  normal 
rate  of  filtration  has  been  attained,  the  deposit  on  the  surface  of 
the  sand  increases  from  day  to  day,  and  the  effective  head  neces- 
sary to  obtain  the  normal  discharge  of  water  from  the  filter  will 
also  have  to  be  increased  by  adjustment  of  the  sluice  gate  in  the 

*  In  the  Journal  of  the  Sanitary  Institute,  October,  1895,  p.  387,  Professor  Percy  Frank- 
land  says : — 

"  It  is  of  importance  to  hasten  the  formation  of  the  surface  slime ;  and  to  this  end  the  water 
should  be  run  onto  the  filter,  and  left  there  undisturbed  for  twelve  hours  before  filtration  is 
actually  commenced." 


UNIVERSITY 


THE   FILTERS   OF   THE   BERLIN    WATER-WORKS.  235 

• 

effluent  chamber.  With  these  filters,  according  to  Mr.  Gill's  rules, 
when  the  difference  of  water  level  on  the  sand-bed  and  in  the 
sluice  chamber  reaches  1.64  feet,  the  filter  must  be  taken  out  of 
service. 

Upon  taking  a  filter  out  of  service  the  influent  and  effluent 
valves  are  closed,  and  the  water  level  lowered  to  the  layer  of  gravel, 
or  to  the  floor  of  the  filter,  no  water  being  left  in  the  bed  of  sand. 
It  is  desirable,  each  time  a  filter  is  taken  out  of  service,  to  thor- 
oughly aerate  the  sand-bed.  The  upper  surface  of  the  sand  is 
pared  with  shovels,  the  cut  in  the  surface  not  exceeding  0.4  inch. 
Care  should  be  observed  to  avoid  taking  off  a  thicker  layer  of  the 
"fouled"  sand.  The  scraped  sand  is  gathered  in  heaps  in  the 
center  of  each  vault,  and  carried  in  barrows  to  the  sand-house  for 
washing  and  storage. 

Mr.  Gill  thinks  that  a  closed  filter,  after  cleaning,  should  be 
exposed  to  the  atmosphere  for  several  days  (excepting  in  winter, 
when  the  temperatures  are  below  the  freezing-point),  and  thor- 
oughly ventilated  before  it  is  started  again. 

"  Fouled"  sand  from  a  filter  is  washed  and  stored  until  required 
to  renew  the  thickness  of  bed  in  the  filter.  In  all  cases  the  origi- 
nal thickness  is  reduced  to  16  inches.  After  the  last  paring  has 
been  taken  from  the  surface,  the  bed  is  filled  with  washed  sand 
until  the  original  thickness  is  obtained. 

After  sand  has  been  scraped  from  a  filter  and  taken  to  the 
washing-machine,  it  should  be  so  thoroughly  washed  that  a  sample 
stirred  in  a  beaker  of  distilled  water  will  produce  no  turbidity. 

The  sand- washers  used  at  Berlin  (Fig.  29)  are  of  the  revolv- 
ing-drum type,,  the  kind  originally  in  use  at  Hamburg,  and  which 
were  discarded  there  for  the  ejector  washers  described  in  Chap- 
ter XIII. 

In  the  operation  of  these  washers,  the  rate  at  which  the  mate- 
rial is  worked  through  the  drum  will  depend  upon  the  speed  of 
rotation,  whil'e  the  quantity  of  water  supplied  to  the  drum  is  regu- 
lated by  a  tap  or  valve.  By  varying  the  speed  of  rotation  and  the 
flow  of  water,  a  thorough  washing  of  the  material,  no  matter  how 
foul  it  may  be,  can  be  accomplished  by  the  time  the  sand  reaches 
the  discharge  end  of  the  drum. 


236 


THE   PURIFICATION  OF    WATER. 


A  circular  weir  at  the  inlet  end  can  be  raised  or  lowered,  and 
thus  increase  or  diminish  the  volume  of  water  retained  at  all  times 
in  the  drum.  It  is  advisable  (especially  in  summer)  to  wash  the 


scraped  sand  as  soon  as  it  comes  from  the  filters,  and  store  it  ready 
for  future  use. 

The  earliest  recorded  comparison  (see  Chapter  XI.)  of  steril- 


THE  FILTERS   OF   THE   BERLIN   WATER-WORKS.  237 

ized  sand,  and  sand  washed  but  not  sterilized,  was  made  at  the 
Stralau  station  of  the  Berlin  Water-Works,  with  the  result  that 
the  best  nitrate  invariably  was  obtained  from  a  bed  of  washed, 
unsterilized  sand.* 

The  water  from  Lake  Miiggel  is  very  variable  in  bacterial 
contents,  having  sometimes  as  many  as  6,000  colonies  per  cubic 
centimeter,  and  at  other  times  so  few  as  200  colonies  per  cubic 
centimeter.  In  the  operation  of  the  niters  it  is  the  aim  to  keep 
the  bacterial  contents  of  the  filtrate  within  the  German  standard, 
i.e.,  100  colonies  per  cubic  centimeter  of  water;  and  seldom  do  the 
numbers  of  bacteria  exceed  90  per  cubic  centimeter  in  the  filtered 
water,  while  counts  as  low  as  40  per  cubic  centimeter  are  often 
made.  Not  considering  the  time  when  the  bacterial  contents  of 
the  lake  water  is  very  low,  the  general  reduction  of  bacteria  by 
the  niters  is  nearly  99  per  cent. 

*  Lake  Miiggel  Water  Supply,  Gill,  p.  9,  10. 


238  THE  PURIFICATION  OF   WATER. 


CHAPTER   XV. 

THE  FISCHER  FILTER  AND   ANDERSON  PURIFIER. 

THE    FISCHER    PLAQUE    FILTER. 

THIS  is  an  invention  of  Mr.  Fischer,  Director  of  the  water- 
works of  Worms,  Germany,  where  it  has  been  in  operation  for 
four  years  past,  and  consists  of  hollow  plates  or  bricks  about  one 
meter  (40  inches)  square  and  20  cm.  (8  inches)  thick,  with  5  cm. 
(2  inches)  of  space  in  the  middle  of  the  plate,  which  gives  an 
effective  thickness  of  filtering-plate  of  3  inches.  These  plates, 
or  plaques,  are  made  of  a  mixture  of  clean  sharp  sand  and  finely 
pulverized  glass,  obtained  from  the  waste  of  glass-works,  broken 
bottles,  etc.  This  mixture,  when  fused,  may  be  given  any  form 
desired,  and  upon  cooling  forms  a  porous  mass  through  which 
water  may  be  filtered  under  pressures  depending  primarily  upon 
the  density  of  the  material.  The  head  under  which  this  form  of 
filter  works  at  Worms  is  given  in  the  Consular  Report*  as  3  to  4 
feet. 

From  a  drawing  which  accompanies  the  Report,  it  appears  that 
the  hollow  brick,  or  plaque  as  it  is  called,  is  made  up  of  two  solid 
plates,  40  inches  square  and  3  inches  thick,  bolted  together  on  a 
frame  of  metal  (?),  with  which  the  plates  make  water-tight  joints, 
and  leaving  a  water  space  or  cell  between  the  plates  2  inches  in 
width.  These  hollow  plates  or  bricks  are  set  on  edge  in  two  tiers, 
as  shown  by  the  drawing,  in  a  suitable  water-tight  tank  or  res- 
ervoir, with  a  water  space  of  3  or  4  inches  between  adjacent  pairs 
of  plates.  The  reservoir  is  then  filled  with  water  until  a  head  is 
obtained  sufficient  to  secure  the  desired  rate  of  filtration  through 
the  plates. 

The  water  passes  through  the  3-inch  thickness  of  plate  from 
the  tank  to  the  cell  inside,  from  which,  by  suitable  pipes,  it  is 

*  Advance  Sheets  of  U.  S.  Consular  Reports,  February,  1897. 


THE   FISCHER  FILTER  AND   ANDERSON  PURIFIER.        239 


drawn  off  to  the 
clear-water  reser- 
voir. The  suspend- 
ed matter  in  the 
water  is  intercept- 
ed at  or  near  the 
outer  surface  of  the 
plates  ;  and  when 
the  pores  become 
so  plugged  as  to  re- 
duce the  capacity  of 
the  filter  to  a  rate 
of  delivery  at  which 
it  becomes  unprof- 
itable to  operate  it, 
the  water  is  drawn 
from  the  tank,  and 
by  reversing  the 
current  the  filtered 
water  is  caused  to 
pass  from  the  cen- 
tral cells  outward 
through  the  pores  of 
the  plates,  and  the 
accumulated  s  u  s  - 
pended  matter  in- 
tercepted at  the 
surface  is  washed 
away,  and  flushed 
from  the  plates  and 
the  tank  by  a  hand 
hose. 

The  principle  of 
filtration  is  the  same 
as  that  employed  in 
the  Berkefeld  and 
Pasteur  type  of  fil- 


240  THE   PURIFICATION  OF   WATER. 

ters,  and  the  method  of  reversing  the  current  to  wash  the  filter 
the  same  as  is  employed  in  the  mechanical  filter. 

The  original  sand  filter  at  Worms  contained  13,000  square  feet 
of  filtering  surface,  and  filtered  at  the  rate  of  792,510  U.  S.  gal- 
lons per  day,  equivalent  to  2,655,700  gallons  per  acre  per  day ; 
while  a  battery  of  500  of  these  Fischer  plates  or  hollow  bricks 
is  said  to  have  yielded  the  same  amount  of  filtered  water  as  the 
sand  filter. 

Estimating  the  effective  area  of  one  face  of  a  plaque  at  one 
square  meter,  and  of  both  faces  at  two  square  meters,  or  21.528 
square  feet,  then  500  such  plaques  (of  which  30  are  shown  in  Fig. 
30,  each  pair  of  plates  being  bolted  together  making  a  hollow 
brick)  would  contain  10,764  square  feet,  and  the  rate  of  percolation 
through  the  3  inches  of  porous  material  would  be  73.6  gallons 
per  square  foot  per  day,  equivalent  to  a  vertical  rate  of  9.8  feet  per 
day. 

(It  is  stated  in  the  Report  that  the  estimated  cost  of  a  sand 
filter  of  13,000  square  feet  of  area  was  130,000,  which  would  make 
the  cost  per  acre  more  than  1100,000.  This  figure  seems  to  be  in 
error  ;  for  nothing  approaching  it  in  cost  has  heretofore,  within  the 
author's  knowledge,  been  reported.  Open  filters  in  series,  includ- 
ing clear-well  and  accessories  upon  an  elaborate  plan,  can  be  con- 
structed in  this  country  within  a  cost  of  $40,000  per  acre,  and 
estimating  concrete  coverings  at  $11,000  per  acre,  the  cost  of 
covered  filters  may  be  as  low  as  $51,000  per  acre,  which  is  about 
one-half  the  cost  assigned  in  the  Report  for  the  sand  filters  in  use 
at  Worms  prior  to  the  introduction  of  the  Fischer  filter.) 

The  Fischer  filter  cost  $9,600,  or  about  $12,000  for  1,000,000 
gallons  of  daily  capacity. 

The  Report  states,  "  From  a  long  series  of  analyses  and  careful 
observations  made  by  the  sanitary  authorities  at  Worms,  it  appears 
that  the  efficiency  of  the  two  systems  of  filtration,  which  are  there 
worked  side  by  side,  are  practically  identical,  so  far  as  regards 
their  effect  upon  the  chemical  purity  of  the  water  ;  but  the  percent- 
age of  bacteria  left  by  the  Fischer  process  is  somewhat  greater 
than  is  left  by  the  sand  filter,  when  clean  and  in  good  working 
condition." 


THE   FISCHER  FILTER  AND   ANDERSON  PURIFIER.         241 

The  porosity  of  these  Fischer  plaques  is  doubtless  greater 
than  the  porcelain  tubes  of  the  Pasteur-Chamberland  filter,  through 
which  bacteria  are  known  to  grow  within  a  few  days  after  sterili- 
zation ;  and  since  sterilization  of  these  sand  and  glass  plaques  is 
not  practicable,  —  only  washing  with  a  reversed  current  of  filtered 
water,  —  there  is  danger  of  the  same  deterioration  of  quality  of 
filtrate  which  has  often  been  observed  by  the  continuous  use 
(unsterilized)  of  the  Pasteur  tubes. 

THE    ANDERSON    REVOLVING    IRON    PURIFIER. 

The  following  description  of  this  device  and  its  mode  of  opera- 
tion is  taken  from  a  recent  publication  by  the  Anderson  Purifier 
Company  entitled  Water  Purification  :  — 

"  This  process  consists  in  passing  the  water  while  on  its  way  to  the  settling- 
beds  through  a  wrought-iron  cylinder  (Fig.  30  «),  supported  horizontally  on 
hollow  trunnions  forming  the  inlet  and  outlet  to  the  cylinder.  This  is  kept 
in  continual  slow  rotation,  and  contains  a  charge  of  metallic  iron  in  small 
pieces.  The  iron  is  continually  lifted  and  showered  down  through  the  water 
by  means  of  scoops  fixed  within  the  cylinder.  The  speed  of  rotation  of  the 
machine  is  about  6  feet  per  minute  at  the  periphery.  The  water  is  passed 
through  at  the  rate  of  from  a  third  to  a  fifth  of  the  capacity  of  the  cylinders 
per  minute,  thus  keeping  the  water  in  contact  with  the  iron  for  from  three  to 
five  minutes,  according  to  the  quality  of  the  water.  The  cylinders  are  made  in 
various  sizes;  for  example,  a  machine  18  feet  long  and  5  feet  in  diameter  is 
capable  of  treating  nearly  a  million  gallons  per  day,  and  is  charged  with  about 
2  tons  of  any  sort  of  scrap  iron,  one  of  the  most  convenient  forms  being  punch- 
ings  from  boiler  plates. 

"  This  churning  with  scrap  iron  causes  the  water  to  take  up  a  small  quantity 
of  iron,  from  a  tenth  to  a  fifth  of  a  grain  per  gallon,  which,  in  precipitation, 
effects  the  purification  of  the  water. 

"  On  leaving  the  cylinder  these  particles  of  iron  are  in  the  form  of  ferrous 
hydrate ;  but  as  the  water  is  immediately  exposed  to  the  influence  of  the  air,  this 
becomes  quickly  changed  to  ferric  hydrate,  which  is  precipitated  in  particles 
more  or  less  coarse  according  to  the  nature  of  the  water  under  treatment.  On 
leaving  the  cylinder  the  water  is  passed  into  a  settling-bed,  or  simple  troughs, 
in  which  the  iron  is  completely  oxidized  by  exposure  to  the  air,  and  in  which 
the  precipitate  immediately  settles. 

"  The  action  of  the  ferric  hydrate  on  all  impurities  in  the  water  is  one  of 
coagulation,  the  formation  of  a  precipitate  in  the  water  tending  to  throw  out 
of  solution  the  dissolved  organic  substances.  This  explanation  of  the  action 
of  the  iron  process  upon  the  organic  impurities  of  a  water  applies  equally  well 


242 


THE  PURIFICATION  OF   WATER. 


to  its  action  upon  microbes.  Experience  shows  that  the  microbes  become 
entangled  in  the  precipitate,  and  either  subside  with  it  to  the  bottom  of  the 
settling-tank,  or  remain  upon  the  surface  of  the  filter/' 


After  extensive  experiments  had  been  made  with  this  process 
upon  the  sewage-polluted  water  of  the  River  Seine  at  Boulogne- 


THE  FISCHER   FILTER  AND  ANDERSON  PURIFIER.        243 

sur-Seine,  with  very  gratifying  results  according  to  the  report  of 
Dr.  Miquel,  it  was  adopted  by  the  Compagnie  Generale  des  Eaux, 
for  the  supply  of  the  suburbs  of  Paris.  The  process  has  been 
made  a  part  of  the  works  at  Choisy-le-Roi,  Nogent-sur-Marne,  and 
Neuilly-sur-Marne,  and  is  proportioned  for  the  treatment  (at  all 
the  stations)  of  18,500,000  U.  S.  gallons  per  diem. 

From  Dr.  Miquel's  bacterial  tests  of  the  performance  of  this 
process  at  Boulogne-sur-Seine,  the  following  averages  for  a  period 
of  six  months,  February  to  July  inclusive,  1893,  are  taken  :  — 

COLONIES  PER  C.  C.  OF  WATER. 

Unfiltered  water  from  River  Seine,  396,000 

Filtered  water,  1,702 

Percentage  of  reduction,  99.57 

The  water  of  the  River  Vanne,  at -the  same  time,  contained 
1,110  colonies  per  cubic  centimeter.  This  is  a  very  pure  water 
from  protected  mountain  sources,  107  miles  distant,  and  in  Paris 
is  regarded  as  the  standard  for  dietetic  water. 

The  method  pursued  by  Dr.  Miquel  and  other  French  workers 
in  bacteriology  is  calculated  to  show  the  bacteria  per  cubic  centi- 
meter of  a  water  sample  about  ten  times  as  high  as  the  method 
employed  in  Germany,  England,  and  America ;  and  for  comparison 
with  our  statements  of  the  bacterial  counts  from  various  waters 
his  figures  should  be  divided  by  this  number,  which  will  give  about 
the  following  results  :  — 

BACTERIA  PER  C.  C. 

Seine  water  (unfiltered),  39,600 

Seine  water  (filtered),  170 

Vanne  water,  111 

The  special  merit  of  the  Anderson  process  is  found  in  its 
ability  to  increase  the  rate  of  precipitation  of  the  suspended  mat- 
ter, including  bacteria,  without  the  use  of  chemicals  as  a  coagulant, 
the  same  result  being  accomplished  by  the  "ferrous  hydrate," 
formed  by  the  contact  of  the  iron  particles  with  the  water,  which 
upon  aeration  is  precipitated  as  a  "  ferric  hydrate." 

According  to  the  circular  from  which  the  above  information  was 
drawn,  the  expense  of  operating  the   small  plant,  including  the 


244  THE   PURIFICATION  OF   WAITER. 

filters,  at  Boulogne-sur-Seine,  was  about  $1.50  per  million  U.  S. 
gallons.  The  process  is  not  in  use  in  any  English  water-works, 
although  tried  at  one  time  under  unfavorable  conditions  at  the 
water-works  of  Worcester.*  Of  this  test  Dr.  Dupre  says:  — 

"1.  The  revolving  purifier  process,  judged  merely  from  a  chemical  point 
of  view,  has  been  a  considerable  success  as  regards  at  least  7  out  of  the  11 
fortnightly  samples  examined  ;  and  if  the  process  could  be  conducted  in  such 
a  manner  that  all  the  filtered  water  equaled  these,  there  would  be  nothing  left 
to  desire ;  while  from  a  bacteriological  point  of  view  it  has  been  eminently  suc- 
cessful in  practically  every  case. 

"  2.  From  a  sanitary  point  of  view  most  of  the  samples  of  filtered  water 
are  open  to  no  objection. 

"3.  The  process,  as  hitherto  worked  at  Worcester,  does  not  effect  any 
very  noticeable  reduction  in  the  color  of  the  water  whenever  there  is  much 
peaty  matter  present. 

"  4.  From  a  sanitary  point  of  view  the  presence  of  peat  is  not,  however,  a 
serious  evil. 

"  5.  Similar  results  might  no  doubt  have  been  obtained  by  means  of  sand 
filtration  only.  To  obtain  them  in  this  way  it  would,  however,  be  necessary  to 
increase  the  present  filtering  area  by  at  least  50  per  cent,  since  the  rate  of  fil- 
tration should  then  not  exceed  4  inches  per  hour;  whereas  the  present  rate  of 
supply  cannot  be  kept  up  under  a  rate  of  at  least  6  inches  per  hour,  and  even 
then  no  provision  would  be  made  to  supply  the  place  of  filters  thrown  out  of 
work  for  cleaning." 

The  author's  experiments  with  a  small  Anderson  purifier  (on 
the  Ohio  River  water)  have  given  as  averages  of  several  tests 
from  86.13  to  97.28  per  cent  reductions  of  the  bacteria  in  the  raw 
water ;  but,  as  stated  in  Chapter  III.,  this  purifier,  and  especially 
the  filter  used  in  connection  with  it,  were  not  calculated  to  favor 
the  process,  and  should  not  be  weighed  against  the  more  elabo- 
rate experiments  of  Dr.  Miquel,  1893,  on  the  process  as  used  at 
Boulogne-sur-Seine. 

The  claims  by  the  manufacturers  for  the  Anderson  rjrocess  of 
treatment  before  the  water  enters  the  subsiding  reservoirs  are :  — 

"  1.  Filtration,  after  the  water  has  been  purified  by  means  of  the  revolving 
purifier  process,  is  carried  on  at  about  twice  the  customary  speed,  thus  effect- 
ing a  saving  of  about  half  the  area  of  filter  surface  required. 

*  Report  of  Dr.  A.  Dupre,  London,  November,  1892. 


FILTERS  PROPOSED  FOR   CINCINNATI.  245 

"  2.  The  saving  thus  effected  much  more  than  counterbalances  the  cost  of 
the  revolving  cylinders. 

"  3.  The  purification  is  much  more  thorough  and  much  less  liable  to  ac- 
cidental disturbance,  and  removes  a  greater  percentage  of  microbes. 

"4.  The  working  cost  is  low,  as  the  iron  employed  is  very  cheap,  and 
with  efficient  settlement  the  cost  of  filter  cleaning  is  very  small." 

The  cost  of  a  revolving  purifier  plant,  including  all  usual  con- 
nections, is  stated  at  $5,000  per  million  gallons  of  daily  capacity. 
A  series  of  cylinders,  and  the  usual  connections  and  appurtenances 
(not  including  the  filters),  required  to  treat  20,000,000  gallons  of 
water  daily,  would  thus  cost  $100,000. 

According  to  Mr.  E.  Devonshire  of  the  Anderson  Purifier 
Company,  the  cost  of  plain  sand  filters  abroad  is  $15,000  to 
$20,000  per  million  gallons  of  daily  capacity,  while  with  the  re- 
duced filter  area  required  by  the  Anderson  process,  these  figures 
are  reduced  to  $9,000  and  $12,000  per  million  gallons  of  daily 
capacity ;  and  he  estimates  the  average  cost  of  a  combined  purify- 
ing and  filtering  plant  at  $15,500  per  million  gallons  of  capacity 
per  day.  It  is  stated  by  the  company  that  the  cost  of  treatment 
by  this  process,  including  the  care  of  the  sand  filters,  "will  not 
exceed  $2.00  per  million  gallons." 


246  THE   PURIFICATION  OF   WATER. 


CHAPTER    XVI. 

FILTERS   PROPOSED   FOR   CINCINNATI. 

THE  water  supply  of  Cincinnati  has  for  years  been  in  a  deplo- 
rable condition,  and  different  measures  for  relief  have  been  proposed 
at  various  times  during  the  past  thirty  years.  As  early  as  1865 
Mr.  James  P.  Kirkwood  proposed  settling  reservoirs  and  plain  sand 
filters  for  the  treatment  of  the  Ohio  River  water  before  it  was 
supplied  to  the  consumers.  This  method  of  water  purification, 
with  such  modifications  as  the  intervening  time  has  suggested, 
was  recommended  by  the  Commission  of  Engineers  appointed  to 
report  plans  and  estimate  of  cost  for  extension  and  betterment  of 
the  city  water-works.*  The  plans  embrace  subsidence  in  large 
reservoirs  for  four  days  previous  to  the  delivery  of  the  water  to 
the  filters. 

The  premises  and  conclusions  upon  the  matter  of  water  puri- 
fication, as  set  forth  in  the  Report  of  the  Engineer  Commission, 
abridged  and  corrected  for  the  present  purpose,  were  as  follows  :  — 

"  Experiments  indicate  that  subsidence  for  four  days  will  remove 
from  the  Ohio  River  water  a  very  large  percentage  of  the  suspended 
matter,  and  relieve  the  filters  of  that  part  of  the  work  which  is 
chiefly  concerned  in  the  clarification  of  the  water.  The  effect  of 
this  will  be  to  cause  the  filters  to  pass  a  larger  quantity  of  water 
per  unit  of  area  between  successive  parings  or  cleanings  of  the 
sand." 

"  Much  of  the  work  now  required  of  the  filters  abroad  will  be 
accomplished  in  the  subsiding  reservoirs  ;  and  by  a  fair  division  of 
the  work  between  the  subsiding  reservoirs  and  the  filters,  relying 
upon  the  former  largely  for  clarification  and  improvement  of  the 
color,  and  upon  the  latter  wholly  for  the  reduction  of  the  bacteria 

*  This  commission  reported  March  20, 1896. 


FILTERS  PROPOSED   FOR    CINCINNATI.  247 

(and  finer  suspended  matter),  better  results  can  be  had  in  the 
quality  of  effluent  and  economy  of  operation  than  by  filtration 
alone." 

"  The  subsiding  reservoirs  have  been  designed  for  ready  cleans-- 
ing from  the  silt  and  other  suspended  matter  in  the  water  which 
will  be  deposited  upon  the  bottom  and  slopes,  and  are  so  arranged 
in  unit  capacity  that  at  all  times  at  least  250,000,000  gallons,  and 
usually  300,000,000  gallons,  cf  sedimentation  capacity  will  be  in 
service." 

"  The  filters  were  designed  for  a  total  capacity  of  66,000,000 
gallons  per  day,  and  a  least  effective  capacity  of  60,000,000  gallons 
per  day.  The  net  aggregate  area  of  water  and  sand  surface  is 
22  acres,  allotting  two  acres  to  each  of  the  eleven  filters.  The 
estimated  rate  of  delivery  is  3,000,000  gallons  per  acre  per  day." 

"To  obtain  the  highest  quality  of  effluent  with  the  maximum 
allowable  rate  of  filtration,  regulators  will  be  used  on  both  the 
inflow  and  outflow  pipes,  limiting  the  head  on  the  sand-bed  and 
the  loss  of  head  between  the  water  on  the  filter  and  the  level  of 
water  in  the  effluent  chambers  to  such  measures  as  may  be  found 
to  give  the  most  satisfactory  results  in  practice." 

The  subsiding  reservoirs  are  six  in  number,  and  each  has  a 
capacity  of  50,000,000  gallons  when  filled  to  a  depth  of  30  feet. 
The  bottom  dimensions  are  705  feet  by  210  feet,  with  dimensions 
at  the  full  water-line  of  855  feet  by  360  feet.  The  top  width  of 
embankment  has  been  fixed  at  20  feet,  with  inside  slopes  2J  hori- 
zontal to  one  vertical,  and  outside  slopes  2  horizontal  to  one  verti- 
cal. The  bottom  and  inside  slopes  are  to  be  covered  with  2  feet 
of  puddle,  over  which  will  be  a  pavement  of  concrete  6  inches 
thick.  The  top  of  the  embankment  will  be  paved  with  concrete 
and  small  broken  stone  rolled  in  place,  to  form  a  foot-walk  and 
driveway  around  and  between  the  reservoirs. 

The  dimensions  of  sand-bed  and  water  surface  of  each  filter 
are  220  feet  wide  by  400  feet  long.  The  depth  of  the  filter,  from 
the  top  of  coping  to  the  concrete  floor,  is  11  feet.  The  filters 
have  been  planned  with  masonry  walls,  vertical  on  the  inside  and 
battered  by  offsets  on  the  outside.  Under  the  bottom  of  the  filter 
a  layer  of  puddle  12  inches  thick  has  been  shown,  and  over  this 


248 


THE  PURIFICATION  OF   WATER. 


puddle  is  placed  a  concrete  floor  6  inches  thick.     The  walls  are 
started  on  a  course  of  puddle  12  inches  thick,  with  a  broad  footing, 


Fig.32b. Transverse  Section. 
F/grs.  37  anrf  32.    Proposed  Filter  Bed  for  the  City  of  Cincinnati,  0.,  1896. 

and  around  the  walls  puddle  of  varying  widths  will  be  packed  up 
to  the  level  of  the  ground. 


FILTERS  PROPOSED   FOR    CINCINNATI.  249 

Each  filter  has  two  acres  of  sand  and  water  surface,*  and  is 
provided  with  two  main  drains  laid  to  a  grade  of  6  inches  in  200 
feet,  each  main  drain  being  graded  from  the  center  of  the  length 
of  the  filter  chamber  to  the  effluent  chambers  at  the  ends  of  the 
filter,  to  collect  the  water  from  one-fourth  the  area  of  the  filter, 
and  discharge  this  right  and  left  to  the  effluent  chambers."  The 
dimensions  of  each  section  are,  therefore,  110  feet  by  200  feet. 

One  filter  of  2  acres  sand  area  is  divided  into  four  parts  or 
sections  of  \  acre  each,  from  which  the  filtered  water  is  collected, 
and  delivered  to  the  four  effluent  chambers  ;  and  any  variation  in 
the  quality  of  filtrate  supplied  by  each  \  acre  of  the  filter  can  be 
detected  by  proper  tests  of  the  water  at  the  effluent  chambers. 
The  sections,  Figs.  32  a  and  32  b,  show  the  method  of  construction 
proposed.  The  excavation  will  be  carried  to  such  bottom  eleva- 
tion as  will  provide  for  the  filling  between  and  for  the  embank- 
ments around  the  filters,  with  due  allowance  for  shrinkage  in 
volume  of  material  by  rolling  and  the  action  of  the  elements. 

The  concrete  floor  and  masonry  side  and  end  walls  constitute 
the  basin  or  reservoir  for  the  reception  of  the  main  and  lateral 
drains  and  the  filtering  materials.  Each  section  of  the  floor  is  a 
shallow  trough,  with  a  general  grade  toward  its  respective  effluent 
chamber.  The  regulator  on  the  influent  side  of  the  filter  consists 
of  a  30-inch  balanced  valve,  and  a  metal  float  which  closes  the 
influent  valve  when  a  head  of  4  feet  over  the  sand  layer  is  reached. 
Upon  the  effluent  side  the  yield  of  the  filter  is  conducted  to  the 
clear-well  through  a  24-inch  pipe,  controlled  by  a  balanced  valve 
and  float,  which  limits  the  delivery  of  each  \  acre  of  the  filter  to 
1,500,000  gallons  per  day. 

"  The  main  drains  are  built  of  brick,  with  portholes  in  the 
three  upper  courses  to  receive  the  water  from  the  small  lateral 
drains,  and  are  covered  with  close  jointed  stone  slabs  3  inches 
thick.  The  walls  of  the  main  drains  are  12  inches  thick,  and 
rest  on  a  concrete  foundation  6  inches  thick." 

The  main  drains  are  2  feet  wide  and  2  feet  high  in  the  clear, 
two  of  which  are  provided  for  each  acre  of  filtering  surface. 

"  The  lateral  drains  are  of  vitrified  salt-glazed  tile,  with  butt 

*  Compare  Hamburg  Filters,  Chap.  XIII. 


250  THE   PURIFICATION  OF   WATER. 

joint  of  arched  section  with  flat  bottoms,  and  perforated  on  the 
top  and  sides.  The  inside  dimensions  are  6  inches  wide  and 
8  inches  high.  These  are  laid  on  the  concrete  floor  to  a  grade 
of  3  inches  in  52.5  feet.  The  lateral  drains  are  spaced  11.8  feet 
center  to  center. 

"  The  filtering  materials  are  arranged  as  follows  :  — 

Fine  graded  sand  (at  top  of  filter),  30  inches. 

Coarse  sand,  15      " 
Small  gravel,  6      " 

Coarse     "  L5      " 

Total  depth  of  filtering  materials,  66  inches. 

Depth  of  water  over  sand,  48      " 

"  Each  filter  is  provided  with  one  influent  and  four  effluent 
chambers  ;  and  each  chamber  is  provided  with  an  automatic  regu- 
lating-valve to  control  the  depth  of  water  over  the  sand-bed,  and 
regulate  the  rate  of  flow  from  the  filters  to  the  clear-well.  Each 
filter  is  supplied  through  a  30-inch  branch  pipe,  connected  with  a 
48-inch  supply  main.  Each  branch  pipe  is  provided  with  a  stop- 
valve  to  shut  off  the  flow  to  the  filter  when  it  is  out  of  service 
and  being  cleaned.  Provision  also  is  made  for  the  draining  of  the 
water  to  such  level  below  the  surface  of -the  sand-bed  as  may  be 
desired,  or  to  empty  the  filter  of  water  altogether. 

From  the  influent  chamber  two  lines  of  20-inch  cast-iron  pipe 
pass  right  and  left  across  the  ends  and  down  the  longer  sides  of 
the  filter,  from  which  short  pieces  of  8-inch  cast-iron  pipe  de- 
liver the  unfiltered  water  on  the  filter-bed.  These  branch  pipes 
are  placed  40  feet  center  to  center. 

The  author  believes  that  the  influent  pipes  should  enter  the 
filter  a  few  inches  (not  more  than  one  foot)  above  the  sand,  to 
avoid  the  necessity  of  a  complete  refilling  of  a  filter  with  filtered 
water,  and  the  disturbance  of  the  sand  surface  by  the  fall  of  water 
from  the  influent  pipes  while  filling  a  filter  to  the  standard  level. 

"  The  clear-well  is  planned  as  a  masonry  structure,  with  walls 
vertical  on  the  inside  and  battered  by  offsets  on  the  outside,  and 
is  started  on  a  layer  of  puddle  18  inches  thick,  over  which  is 
placed  a  layer  of  concrete  6  inches  thick.  Outside  the  walls  pud- 


FILTERS  PROPOSED   FOR   CINCINNATI.  251 

die  of  varying  widths  will  be  rammed  up  to 'a  level  with  the 
ground.  The  clear-well  inside  has  a  length  of  1,180  feet  and  a 
width  of  148  feet,  giving  a  net  area  of  4  acres,  which,  with  a 
depth  of  15  feet,  contains  20,000,000  gallons,  or  one-fourth  of  the 
daily  capacity  of  the  high-service  pumping-engines. 

"  Much  thought  has  been  bestowed  upon  the  problem  of  open 
and  closed  filters  for  Cincinnati,  and  due  consideration  has  been 
given  to  the  practice  of  filter  construction  abroad.  In  latitudes 
where  the  winters  are  rigorous  it  is  essential  that  the  filters  be 
covered  to  secure  good  results. 

"  In  temperate  climates,  like  that  of  London,  all  the  filters  are 
open.  In  the  extreme  climates  of  St.  Petersburg,  Warsaw,  and 
Koenigsberg  the  filters  are  covered  to  avoid  the  danger  due  to  a 
complete  freezing  over  of  the  water  on  the  sand-bed,  and  more 
especially  to  prevent  freezing  of  the  sand  when  the  filter  is  taken 
out  of  service. 

"The  filters  of  Berlin  (a  city  in  a  climate  nearly  like  that  of 
Cincinnati),  are  covered,  while  the  latest  filter  works  of  Germany, 
those  of  Hamburg,  are  of  the  open  type. 

"  The  normal  temperature  of  the  winter  months  should  govern 
in  this  matter ;  and  a  comparison  of  the  temperatures  of  the  three 
winter  months  for  the  past  eleven  years  for  Cincinnati,  with  the 
mean  January  temperatures  of  Berlin  and  Hamburg,  are  given  in 
the  following  table  :  — 

MEAN   NORMAL  WINTER  TEMPERATURES. 
CITY.  DECEMBER.  JANUARY.  FEBRUARY. 

Cincinnati,  36.75  30.66  34.27 

Berlin,  .  .  31 

Hamburg,  .  .  31 

"  From  this  it  appears  that  the  mean  January  temperature  of 
Cincinnati  is  about  the  same  as  that  of  the  German  cities  noted ; 
but  of  the  eleven  years  embraced  in  the  average  for  Cincinnati, 
seven  had  mean  January  temperatures  below  the  freezing-point. 

"  In  the  light  of  th.e  long  and  valuable  experience  of  the  other 
German  cities  in  the  matter  of  filter  construction  and  operation,  it 
is  difficult  to  conceive  how  Hamburg  could  have  made  a  mistake 


252  THE   PURIFICATION  OF   WATER. 

in  a  matter  apparently  so  easy  of  solution  as  the  covering  or  non- 
covering  of  its  niters.  Altona,  adjoining  Hamburg,  and  subject 
to  the  same  winter  climate,  had  used  open  filters  for  thirty-two 
years  before  Hamburg  built  its  filters ;  and  although  some  com- 
plaint had  arisen  in  Altona  against  open  filters,  it  does  not  seem 
that  this  was  strong  enough  to  cause  the  use  of  covered  filters  in 
Hamburg. 

The  commission  decided  to  recommend  filters  without  cover- 
ings, with  a  provision  in  the  report  for  the  vaulting  of  the  filters, 
should  experience  demonstrate  the  necessity  of  these.  Informa- 
tion from  Hamburg,  received  since  the  Report  was  submitted, 
indicates  that  the  covering  of  filters  in  climates  similar  to  Cincin- 
nati is  not  essential  to  satisfactory  results,  either  in  the  quality  of 
filtrate  or  in  the  management  of  the  filters  during  the  winter. 

The  project  of  water  purification  for  Cincinnati  contemplates 
eleven  open  filters,  each  of  two  acres  of  sand  and  water  surface ; 
and  estimating  in  the  usual  manner  for  engineering  structures, 
the  cost  of  the  filters,  including  all  necessary  pipes,  valves,  regu- 
lators, etc.,  is  $65,146.50  for  one  filter.  The  cost  of  clear-well  of 
masonry  construction  was  $162,696.90,  and  the  total  cost  for  the 
filtering-works  was  estimated  as  follows  :  — 

ORIGINAL    PLAN    FOR   CINCINNATI    FILTERS. 

11  filters,  2  acres  of  filtering  area  each,  at  $65,146.50,       $716,611.50 
Clear-well,  20,000,000  gallons  capacity,  162,696.90 

$879,308.40 

Add  10  per  cent  for  sand-washing  and  conveying  ma- 
chinery, contingencies,  etc.,  87,930.84 
45.06  acres  of  land,  at  $150.00,  6,759.00 
Total  for  11  filters,  clear-well,  and  all  appurtenances,  $973,998.24 
Cost  per  acre  of  filtering  area,  44,272.65 
Cost  per  1,000,000  gallons  of  estimated  capacity,  14,757.55 

Subsequent  to  the  report  of  the  commission  the  author  investi- 
gated the  cost  of  these  filters,  if  constructed  after  the  Hamburg 
plan,  with  sloped  walls  of  earth  instead  of  masonry,  the  sand  sur- 
face to  remain  the  same  as  before ;  viz.,  two  acres,  influent  and 
effluent  chambers  of  masonry,  and  all  distributing  and  collecting 


FILTERS  PROPOSED   FOR   CINCINNATI.  253 

9  * 

pipes  and  channels  of  the  same  construction  as  before,  from  which 

the  following  resume  is  drawn  :  — 

AMENDED   PLAN   FOR  CINCINNATI    FILTERS 

11  filters,  2  acres  of  filtering  area  each,  at  $53,960,  $593,560.00 

Clear-water  reservoir,  20,000,000  gallons  capacity,   at 

$3,000  per  million,  60,000.00 

$653,560.00 

Add  10  per  cent  for  sand-washing  and  conveying  ma- 
chinery, contingencies,  etc.,  65,356.00 
52.5  acres  of  land,  at  $150.00,  7,875.00 
Total  for  11  filters,  clear-water  reservoir,  and  all  appur- 
tenances, $726,791.00 
Cost  per  acre  of  filtering  area,  33,036.00 
Cost  per  1,000,000  gallons  of  estimated  capacity,  11,012.00 

In  this  estimate  the  clear-water  reservoir  is  also  considered  as 
a  plain  earthen  reservoir  with  sloped  walls,  paved  with  concrete 
six  inches  thick,  same  as  filter  basins. 

The  estimates  of  cost  for  a  system  of  plain  sand  filtration  for 
Cincinnati  were  made  from  plans  prepared  with  unusual  care  in 
view  of  the  novelty  of  the  proposition  to  filter  60,000,000  gallons 
of  river  water  per  diem,  and  it  is  not  known  that  any  feature  of 
successful  filtration  was  omitted  in  the  plans  or  overlooked  in  the 
estimate.  The  prices  for  materials  and  construction  adopted  in 
the  detailed  estimates  are  really  higher  than  the  prices  prevailing 
at  this  time  (1897),  and  the  author  is  confident  that  entirely 
satisfactory  and  durable  works  can  be  constructed  within  the 
estimates  given. 

With  reference  to  the  great  cost  of  the  filter  works  at  Berlin, 
Mr.  Gill's  plans  have  been  studied  very  carefully ;  and  aside  from 
the  fact  that  he  has  included  in  the  cost  of  the  purification  works 
the  cost  of  certain  features  of  the  Lake  Miiggel  works,  which  in  the 
author's  opinion  are  not  strictly  chargeable  to  the  filters,  but  should 
be  charged  to  the  pumping-works,  the  whole  work  was  conducted 
upon  a  very  costly  scale,  scarcely  justified  even  in  permanent  works 
of  public  water  supply. 

(During  a  long  experience  with  public  works  the  author  has 
seen  much  money  wasted  in  certain  details  of  construction  which 


254  THE  PURIFICATION  OF   WATER. 

have  been  due  to  inexperience  or  perverted  judgment  upon  the 
part  of  the  constructors.  Thus  reservoirs,  thoroughly  constructed, 
complete  in  every  essential,  and  as  durable  as  such  structures  may 
be,  have  been  completed  by  some  engineers  at  a  cost  of  $2,500  per 
million  gallons  of  available  capacity,  while  in  other  situations  equally 
as  favorable  for  this  class  of  works,  the  engineer  has  succeeded  in 
using  up  over  $4,000  per  million  gallons  of  reservoir  capacity,  with 
no  material  gain  in  the  quality  of  the  finished  structure.  Point 
lace  on  the  legs  of  a  pair  of  overalls,  or  the  sleeves  of  a  machinist's 
jacket,  would  add  nothing  to  the  utility  of  these  garments,  while 
costing  many  times  as  much  as  the  garments  themselves.  In  like 
manner  the  author  has  seen  works  overloaded  with  trimmings 
which  attract  the  eye,  while  obviously  lacking  in  some  of  the 
essentials  for  convenient  service  and  durability.  In  the  construc- 
tion of  filters  and  appurtenances  the  same  extravagance  which  is 
often  displayed  in  other  engineering  structures  may  enter  into 
these  with  no  benefit  whatever  to  the  works  themselves.) 

The  manner  in  which  the  filters  and  appurtenances  for  the 
Hamburg  Water- Works  were  forced  to  an  early  completion  by 
working  night  and  day,  in  order  to  avoid  the  possible  return  of 
cholera  in  1893,  manifestly  increased  the  cost  of  labor,  and  possibly 
of  materials,  over  the  cost  of  what  might  have  been  obtained  with 
slower  and  more  deliberate  construction ;  and  yet  these  works  are 
very  complete  in  every  essential  of  modern  filter  construction,  and 
cost  a  trifle  over  one-half,  per  acre  of  effective  area,  than  that  of 
the  filters  in  the  Berlin  Water-Works.  The  Berlin  filters  are  cov- 
ered ;  but  allowing  $13,000  per  acre  for  concrete  vaulted  covers, 
then  the  Hamburg  filters  would  have  cost  but  two-thirds  as  much 
as  the  Berlin  filters. 

(The  people  are  always  ready  to  condemn  the  prodigality  of  a 
private  spendthrift,  and  how  much  more  justly  may  we  condemn 
the  public  spendthrifts  who,  through  ignorance  and  arrogance, 
presume  to  squander  the  contents  of  the  public  purse.) 


COST  OF  FILTERS  AND  FILTRATION.  255 


CHAPTER  XVII. 

COST   OF   FILTERS   AND   FILTRATION 

So  many  variable  conditions  enter  into  the  cost  of  construct- 
ing a  system  of  water  filters,  that  any  figures  given  in  a  work  of 
this  kind  must  be  accepted  rather  as  suggestions  than  estimates 
which  can  be  used  with  safety  in  any  locality.  The  topography 
and  nature  of  the  ground  upon  which  filters  are  to  be  constructed, 
the  local  prices  of  labor  and  materials,  the  nearness  and  quality 
of  available  filtering  materials,  the  character  throughout  the  year 
of  the  water  to  be  filtered,  the  necessity  of  previous  sedimenta- 
tion with  certain  waters,  the  quality  of  filtrate  to  be  obtained,  and 
many  other  obvious  conditions,  must  be  taken  into  consideration 
in  determining  and  designing  a  system  of  filters  on  a  large  scale 
for  public  water  supply.  The  same  ingenuity  and  judgment  in 
the  use  of  available  locations  and  materials  of  construction  are 
to  be  taken  advantage  of  in  the  building  of  works  of  filtration,  as 
in  other  engineering  structures.  Successful  filtration  seems  to  be 
more  dependent  upon  management  than  on  the  construction  of  the 
works,  and  plain  construction,  such  as  we  find  in  the  purification 
works  of  Hamburg,  with  the  skill  and  vigilance  there  displayed  in 
the  management  of  the  filters,  will  meet  all  practical  requirements. 

PHILADELPHIA,  PA. 

Mr.  Hazen,  in  a  Report  to  the  Woman's  Health  Protective 
Association,*  estimates  the  cost  of  filters  there  (omitting  value 
of  land)  as  given  in  the  first  table  on  page  256. 

These  prices  include  settling-basins,  low-lift  pumps,  filters  and 
clear-wells,  and  the  pipes,  valves,  and  regulators  required  to  co-n- 
nect  the  filters  in  service.  In  all  instances  noted  above,  the  maxi- 

*  A  Practical  Plan  for  Sand  Filtration  in  Philadelphia,  1896. 


256 


THE   PURIFICATION  OF   WATER. 


STATION. 

DAILY  AVERAGE 
CAPACITY, 
GALLONS. 

GROSS  COST. 

COST  PER  AVERAGE 
MILLION  GALLONS. 

Belmont, 
Queen  Lane, 
Cambria, 
Frankford, 

14,000,000 
26,000,000 
60,000,000 
20,000,000 

$    317,000 
587,000 
1,578,000 
389,000 

$22,643.00 
22.577.00 
26,300.00 
19,450.00 

mum  capacity  of  the  filters  is  50  per  cent  above  the  average,  and 
a  statement  of  cost  upon  the  total  or  maximum  daily  capacity  of 
filters  will  be  as  follows  :  — 


STATION.     ' 

COST  PER  MAXIMUM 
MILLION  GALLONS. 

STATION. 

COST  PER  MAXIMUM 
MILLION  GALLONS. 

Belmont, 
Queen  Lane, 

$15,095.30 
15,051.30 

Cambria, 
Frankford, 

$17,533.30 
12,966.60 

From  Mr.  Shedd's  estimates  on  filters  for  Providence,  R.I.,  the 
following  costs  are  obtained  :  — 


TYPE  OF  FILTER. 

DAILY  CAPACITY, 
GALLONS. 

GROSS  COST. 

COST  PER  MILLION  GAL- 
LONS OF  CAPACITY. 

Mechanical, 
Plain  sand, 
Proposal  on  plain  sand, 

15,000,000 
« 
« 

$281,000 
208,000 
200,000 

$18,733.30 
13,866.60 
13,333.30 

According  to  Mr.  Hazen,*  covered  filters  on  the  European 
model  will  cost  $70,000  per  acre,  or  allowing  for  a  rate  of  filtra- 
tion of  2,500,000  gallons  per  acre  per  day,  the  cost  per  million 
gallons  of  daily  capacity  will  be  828,000  ;  but  upon  comparison 
with  careful  estimates  by  the  author,  on  open  and  covered  filters, 
for  the  city  of  Cincinnati,  this  price  is  excessive. 

Open  filters,  not  including  clear-well,  sand-washing  and  con- 
veying machinery,  and  land,  if  built  on  favorable  ground,  should 
cost,  in  the  vicinity  of  Cincinnati,  as  follows:  — 

With  vertical  masonry  walls,  per  acre  of  filtering  area,  $32,573.30 
With  earthen  embankments,  and  slopes  paved  with 

concrete,  per  acre  of  filtering  area,  $26,980.00 


*  Filtration  of  Public  Water  Supplies,  p.  120. 


COST  OF  FILTERS  AND  FILTRATION.  257 

Estimates  furnished  the  author  by  an  expe*rt  in  concrete  con- 
struction indicate  that  concrete  coverings  for  above  filters  will 
cost  about  111,000  and  113,000  respectively  per' acre  of  effective 
sand  surface  ;  making  the  cost  of  covered  filters  as  follows  :  — 

COVERED   FILTERS. 

With  vertical  masonry  walls  and  concrete  coverings, 

per  acre  of  filtering  area,  $43,573.00 

With  earthen  embankments,  slopes  paved  with  con- 
crete and  coverings  of  concrete,  per  acre  of  filter- 
ing area,  $39,980.00 

In  his  Report  to  the  city  of  Albany,  Mr.  Hazen  modifies  his 
estimate  of  cost  somewhat.*  Here  he  gives  the  cost  of  eight  fil- 
ters (0.70  acre  each)  at  $251,000,  to  which  may  be  added  $10,000 
for  piping  about  filters,  etc.,  making  the  cost  of  covered  filters 
$46,607  per  acre,  a  price  which  agrees  more  nearly  with  the  re- 
sults of  the  author's  estimates  of  cost  of  construction. 

The  clear-well,  or  reservoir,  to  equalize  the  delivery  from  a 
system  of  filters,  should  have  a  capacity  equal  to  \  or  \  the  maxi- 
mum daily  yield  of  filters  ;  and  this,  if  constructed  as  a  plain  reser- 
voir with  paved  inner  slopes,  will  cost  from  $2,500  to  $3,500  per 
million  gallons  of  capacity. 

Assuming  10  filters,  open  pattern,  with  earthen  walls  and 
paved  inner  slopes,  of  the  dimensions  given  in  the  description 
of  the  Cincinnati  filters  (Chapter  XVI.),  the  total  cost  of  filters 
and  clear-well,  exclusive  of  land,  should  not  exceed :  — 

10  filters,  2  acres  each,  $539,600.00 

Add  10  per  cent  for  sand  washing  and  conveying 

machinery,  and  contingencies,  53,960.00 

Clear-water  basin,  of  a  capacity  of  20,000,000  gal- 
lons, at  $3,000  per  million,  60,000.00 

Total,  exclusive  of  land,  $653,560.00 

Cost  per  million  gallons  of  daily  capacity  (allowing 
one  filter  to  be  always  out  of  service,  and  2,500,000 
gallons  average  daily  rate  of  filtration  per  acre),  $14,523.55 

*  Report  on  Filtration  of  Water  Supply,  Albany,  1897,  p.  27. 


258  THE   PURIFICATION.   OF   WATER. 

In  the  estimates  for  plain  sand  filters  for  the  proposed  exten- 
sion and  betterment  of  the  Cincinnati  Water-Works,  the  clear- 
well  was  designed  as  a  masonry  structure  of  4  acres  area  and 
17  feet  deep,  and  estimated  to  cost  $163,000,  or  at  the  rate  of 
$7,409  per  acre  of  filtering  area. 

Estimating  on  open  filters  and  clear-well  of  masonry  construc- 
tion, which  may  be  desirable  or  necessary  in  some  locations  :  — 

10  filters,  2  acres  each,  $651,466.00 

Add  10  per  cent  for  sand  washing  and  conveying 

machinery,  and  contingencies,  65,146.60 

Clear-well,  148,180.00 

Total,  exclusive  of  land,  $864,792.60 

Cost  per  million  gallons  of  daily  capacity  (allowing 
one  filter  always  to  be  out  of  service,  and  2,500,000 
gallons  average  daily  rate  of  filtration  per  acre),  $19,217.60 

COST  OF   FILTERS,   INCLUDING  CLEAR-WELLS  AND  ALL  APPURTENANCES. 

Berlin,  covered  (Lake  Miiggel),*  $68,000  per  acre. 

Berlin,  uncovered  (Stralau),  48,570    "       " 

Hamburg,  uncovered,  38,857    "       " 

The  Berlin  covered  filters,  as  will  be  observed  upon  reference 
to  the  description  of  these  in  Chapter  XIV.,  are  of  a  very  costly 
construction ;  and  some  of  the  appurtenances  included  in  the  cost 
are  usually  found  in  existing  water-works  to  which  filtration  may 
in  the  future  be  applied.  The  Hamburg  filters  are  of  the  most 
recent  and  modern  construction,  and  approach  more  nearly  the 
estimated  cost  for  open  filters  in  series  in  this  country. 

From  Mr.  Preller's  paper  on  the  Zurich  Water-Works,!  the 
cost  of  covered  filters  was  $70,857  per  acre,  and  for  the  open  fil- 
ters $46,464  per  acre,  prices  which  are  higher  than  those  of  other 
works  in  Germany.  These  prices  are  stated  to  include  only  the 
filter  basins  and  filtering  materials,  and  possibly  the  pipes,  valves, 
and  conduits  necessarily  included  in  the  construction  of  the  filter 
basins  and  influent  and  effluent  chambers. 

*  Mr.  Gill  states  the  cost  of  the  covered  filters  at  Lake  Miiggel  as  £15,000  per  acre,  equal  to 
$72,750.00.     Mr.  Anklam,  superintendent  of  these  works,  furnishes  the  prices  given  above, 
f  Proceedings  Institution  of  Civil  Engineers,  London,  1892. 


COST  OF  FILTERS  AND   FILTRATION.  259 

The  cost  of  the  Lawrence,  Mass.,  filter  was*$26,000  per  acre ; 
and  this  price  it  is  understood  covers  all  the  work  in  construction 
of  the  filter  and  its  connection  with  the  previously  existing  filter 
gallery,  which  then  became  the  clear-well  of  the  filter. 

The  city  of  Ashland,  Wis.,*  recently  constructed  three  small 
plain  sand  filters,  each  of  \  acre  area,  at  a  gross  cost  of  $40,178.00. 
It  was  estimated  that  the  extra  cost  of  these  filters  due  to  local 
difficulties  was  $5,367.00,  and  the  net  cost  under  ordinary  condi- 
tions was  assumed  at  $34,811.00  for  one-half  acre.  These  filters 
are  covered  with  masonry  instead  of  concrete  vaulting,  which  also 
materially  increased  their  cost.  Two  of  these  filters  have  sand  of 
an  "effective  size"  0.27  mm.  and  "uniformity  coefficient  "  1.9  ; 
and  one  has  sand  of  an  "effective  size"  0.40  mm.  and  a  "uni- 
formity coefficient "  1.6.  The  sand  in  all  beds  is  4  feet  thick. 

RATES    OF    FILTRATION    FOR    PLAIN    SAND    FILTERS. 

The  rates  of  filtration  per  acre  per  day,  as  practiced  in  different 
cities,  are  given  as  follows  :  — 

At  the  time  of  Mr.  Kirkwood's  visit  to  Europe  the  daily  average 
rate  of  percolation  was  3,920,400  gallons  per  acre,  equal  to  12  feet 
vertical  per  day.  Mr.  James  Simpson,  engineer  of  the  Chelsea 
and  Lambeth  Water- Works  (the  pioneer  in  sand  filtration),  adopted 
a  standard  rate  of  86.4  gallons  per  square  foot  (3,763,584  gallons 
per  acre  per  day),  corresponding  to  a  vertical  rate  of  percolation  of 
11.55  feet  per  day.  The  present  average  rate  for  the  London  fil- 
ters is  about  1,800,000  gallons  per  acre  per  day,  corresponding  to 
a  vertical  rate  of  percolation  of  5.52  feet. 

The  filters  of  the  New  River  Works  sometimes  reach  a  rate 
as  high  as  3,136,320  gallons  per  acre  per  day,f  while  the  rate  at 
which  it  becomes  no  longer  profitable  to  operate  a  filter  is  placed 
by  Mr.  Hervey  of  the  West  Middlesex  Works  at  1,303,000  gallons 
per  acre  per  day ;  and  when  the  rate  of  percolation  reaches  2  inches 
per  hour  the  filter  is  taken  out  of  service,  the  sand-bed  scraped, 
and  the  filter  started  for  another  period  of  useful  work. 

*  Engineering  News,  Nov.  25,  1897,  p.  338. 

t  According  to  Mr.  E.  L.  Morris,  engineer  of  these  works. 


260  THE   PURIFICATION  OF    WATER. 

The  Hamburg  rate  is  1,700,000  gallons  per  acre  per  day,  cor- 
responding to  a  vertical  rate  of  5.22  feet.  Mr.  Gill  proposed  for 
the  Miiggel  Lake  filters  for  Berlin  a  vertical  rate  of  8  feet  per 
day,  equal  to  2,606,630  gallons  per  acre  per  day.  The  rate  at 
Zurich  is  5,850,000  gallons  per  acre,  equal  to  a  vertical  rate  of 
17.95  feet  per  day. 

The  rate  proposed  for  a  sand  filter  to  be  used  in  connection 
with  the  Marston  Lake  Water  Supply  for  the  city  of  Denver,  was 
195,500,000  gallons  per  acre  per  day,  corresponding  to  a  vertical 
rate  of  percolation  of  600  feet.*  (There  is  a  suggestion  in  the 
paper  which  describes  these  filters  that  they  were  to  be  operated 
with  a  coagulant,  but  a  late  report  on  them  indicates  that  this  was 
abandoned,  if  ever  used.)  A  filter  devised  for  Tacoma,  Washing- 
ton, is  said  to  work  at  rates  of  22,000,000  to  44,000,000  gallons 
per  acre  per  day,  corresponding  to  vertical  rates  of  67.5  and  135.0 
feet  per  day.f  Plain  sand  filtration  cannot  be  continuously  con- 
ducted at  such  rates  as  these  with  any  improvement  in  the  quality 
of  the  water ;  and  they  are  here  mentioned  in  order  that  the  con- 
trast between  these  rates  and  the  rates  which  long  experience 
abroad  has  sanctioned  may  be  impressed  upon  water-works  offi- 
cials, with  the  hope  that  such  works  of  water  purification  as  may 
be  attempted  in  this  country,  instead  of  showing  an  utter  disre- 
gard of  fundamental  principles,  will,  if  it  is  possible,  be  constructed 
and  operated  upon  plans  which  will  yield  even  better  results  than 
the  works  found  in  the  cities  of  Europe. 

Mr.  Hazen,  in  estimating  upon  the  cost  of  filters  and  filtration, 
employs  a  rate  of  2,500,000  gallons  per  acre  per  day,  correspond- 
ing to  a  vertical  rate  of  percolation  of  7.68  feet. 

From  the  reports  of  the  Massachusetts  State  Board  of  Health, 
satisfactory  results,  both  chemically  and  bacterially,  in  the  filtrate, 
were  had  with  rates  of  filtration  as  high  as  7,500,000  gallons  per 
acre,  corresponding  to  a  vertical  rate  of  23  feet  per  day. 

The  Ashland  (Wis.)  plain  sand  filters,  for  the  year  ending 
February  28,  1897,  were  worked  at  an  average  rate  of  2,180,064 
gallons  per  acre  per  day,  equivalent  to  a  vertical  rate  of  6.69  feet. 

*   Transactions  American  Society  of  Civil  Engineers,  vol.  xxxi.,  pp.  158-60. 
!    Transactions  American  Society  of  Civil  Engineers,  vol.  xxxv.,  p.  44  et  seq. 


COST  OF  FILTERS  AND   FILTRATION.  261 

• 
DURATION    OF    SERVICE    OF    FILTERS. 

The  period  or  interval  of  time  between  cleanings  or  renewal 
of  the  sand  surface  of  a  filter  has  a  direct  bearing  on  the  cost  of 
filtration.  Obviously  the  clearer  the  water  and  the  lower  the  rate 
of  percolation  the  longer  will  be  the  interval  of  service.  With  a 
given  condition  of  the  water  as  it  comes  to  the  filter  the  capacity 
can  be  stated  in  millions  of  gallons  filtered  between  cleanings,  and 
the  capacity  divided  by  the  average  rate  of  percolation  per  day  will 
give  the  number  of  days  of  filter  service. 

Thus,  a  filter  which,  between  parings  of  the  sand-bed,  will 
deliver  60,000,000  gallons  per  acre,  at  an  average  rate  of  perco- 
lation of  2,000,000  gallons  per  acre  per  day,  will  have  a  period 
of  operation  of  30  days.  A  filter  which  will  deliver  100,000,000 
gallons  per  acre,  between  parings  of  the  sand-bed,  at  an  average 
rate  of  percolation  through  the  sand  of  2,500,000  gallons  per  acre 
per  day,  will  have  a  period  of  operation  of  40  days. 

The  period  of  operation  for  the  London  filters  ranges  from 
30  to  40  days,  depending  upon  the  condition  of  the  water  as  it  is 
drawn  from  the  River  Thames  or  River  Lea,  and  the  time  allowed 
for  subsidence  in  the  storage  reservoirs  before  the  water  is  put  on 
the  filters.  From  the  evidence  taken  by  the  Royal  Commission 
on  Metropolitan  Water  Supply  the  period  of  operation  was  given. as 
short  as  21  days  in  one  instance,  and  as  long  as  70  days  in  another. 
One  witness  stated  that  some  of  the  filters  of  his  works  had  been 
in  service  over  forty  years,  without  any  attention  being  given  to 
them  other  than  the  scraping,  washing,  and  replacing  of  the  cleaned 
sand  in  the  beds  from  time  to  time. 

The  Hamburg  filters,  omitting  the  short  periods  which  have 
been  mentioned  as  occurring  during  the  winter,  have  worked  for 
periods  of  47,  51,  and  66  days.  However,  the  usual  period  of  ser- 
vice at  Hamburg  is  about  40  days.  At  Zurich  the  covered  filters 
are  reported  to  have  an  average  period  of  service  of  50  days,  while 
the  open  filters  require  cleaning  every  40  days  of  use.  In  these 
works  the  sand-bed  is  scraped  successively  until  the  remaining 
thickness  is  reduced  to  12  inches. 

At  Berlin  the  filters  are  scraped  after  about  every  40  days  of 


262  THE   PURIFICATION  OF   WATER. 

service ;  and  once  in  four  years  the  whole  bed  of  sand  is  taken  out, 
washed,  and  replaced  in  the  filter. 

During  the  experiments  conducted  by  Mr.  Weston,  with  small 
plain  sand  filters  at  Providence,  at  rates  of  percolation  less  than 
30,000,000  gallons  per  acre  per  day,  the  periods  of  operation 
ranged  from  30  to  50  days,  while  at  the  higher  rates  of  percolation 
the  period  of  operation  was  about  20  days. 

The  general  practice  by  the  London  water  companies,  in 
restoring  a  filter  to  service  from  time  to  time,  is  to  scrape  off 
about  |  inch  of  the  clogged  sand  until  a  minimum  thickness 
(varying  with  the  different  companies)  of  the  sand-bed  is  reached, 
whereupon  the  whole  bed  of  sand  is  readjusted  in  position.  The 
sand  remaining  after  the  last  scraping  is  then  taken  out  of  the 
filter,  and  replaced  by  the  sand  previously  scraped  from  the  bed 
and  washed,  above  which  the  other  sand  in  the  filter  is  spread, 
scraped  off,  and  washed  in  due  time.  By  this  method  the  whole 
bed  of  sand  at  long  intervals  is  scraped  off,  taken  to  the  washer, 
and  returned  to  the  filter.  Thus  during  one  complete  cycle  of 
"filling"  and  "scraping"  of  the  sand-bed,  the  whole  body  of  sand 
will  be  rotated,  the  lower  sand  coming  to  the  top  of  the  filter,  and 
the  previous  top  sand  going  to  the  bottom,  thus  avoiding  the 
probability  of  converting  the  lower  portion  of  the  sand-bed  into 
a  favorable  soil  for  the  cultivation  of  bacteria. 

As  stated  in  a  previous  chapter,  the  filters  of  some,  if  not  all, 
the  London  water-works  are  generally  scraped  and  the  sand  de- 
livered on  the  banks  of  the  filter  by  contract,  the  price  paid  being, 
as  stated  by  Mr.  W.  B.  Bryan,  engineer  of  the  East  London  Water 
Company,  X5,  or  about  $25.00  per  acre. 

The  period  of  operation  of  the  sand  filter  at  Lawrence,  Mass. 
(1895),  was  about  27  days,  and  at  each  scraping  of  the  sand-bed 
|  inch  was  taken  off  and  washed.  The  sand  is  washed  by  ma- 
chinery. During  1895,  1,500  cubic  yards  of  "fouled"  sand  were 
scraped  from  the  filter  and  washed,  at  a  cost  of  68  cents  per 
cubic  yard,  or  81.02  per  million  gallons  of  water  filtered.  About 
\\  cubic  yards  of  sand  were  scraped  per  million  gallons  of  water 
drawn  from  the  filter.  At  Hamburg  about  two  cubic  yards  of 
sand  are  scraped  off  the  filters  and  washed  per  million  gallons 


COST  OF  FILTERS  AND   FILTRATION.  263 

of  water  filtered.  There  the  cost  per  cubic  yard  of  scraping  and 
washing  sand  is  considerably  less  than  the  cost  of  washing  alone 
at  Lawrence.  This  is  partly  to  be  accounted  for  by  the  much 
larger  quantity  of  sand  scraped  and  washed  at  Hamburg,  and  by 
the  lower  cost  of  common  labor. 

In  the  report  of  the  Ashland  (Wis.)  filters  mentioned  on 
page  259,  it  is  stated  that  the  cleaning  of  the  sand  of  one  bed 
(£  acre)  for  the  year  ending  February  28,  1897,  consumed  £ 
clay,  and  cost  18.50,  making  the  cost  of  removing  and  cleaning 
the  sand  per  acre  $51.00.  The  total  cost  for  cleaning  and  renew- 
ing the  sand  for  one  year  was  $899.37,  during  which  time  the 
filters  delivered  397,860,000  gallons  of  water,  with  a  cost  of 
$2.26  per  million  gallons  filtered.  While  the  cost  per  acre  for 
cleaning  and  renewing  the  "fouled"  sand  is  very  high  even  for 
small  filters  like  these,  the  cost  per  million  gallons  of  water  filtered 
is  correspondingly  low,  and  suggests  the  probability  of  a  poor 
quality  of  filtrate. 

LOSS    OF    WATER    IN    CLEANING    FILTERS. 

The  cost  of  washing  sand  at  Berlin  is  stated  at  2,020  gallons 
of  water  per  cubic  yard ;  while  at  Hamburg,  with  the  ejector 
washers,  the  consumption  of  water  is  said  to  be  4,040  gallons  per 
cubic  yard  of  sand.  At  Zurich  the  cost  of  washing  sand  by 
machinery  is  given  at  17  \  cents  per  cubic  yard,  but  no  mention  is 
made  of  the  quantity  of  water  required,  while  the  cost  of  washing 
and  placing  the  sand  in  the  filters  is  reported  as  46  cents  per 
cubic  yard.  This  is  for  the.  new  sand,  and  the  price  doubtless  is 
larger  than  for  washing  and  replacing  the  "  fouled  "  sand  scraped 
from  the  filters. 

In  Chapter  XII.,  the  statement  is  made  upon  the  authority  of 
Mr.  E.  B.  Weston  that  the  filtered  water  required  to  wash  the 
sand-bed  of  the  Morison  mechanical  filter  during  the  Providence 
tests,  and  the  water  run  to  waste  after  the  filter  was  started, 
represented  about  eight  per  cent  of  the  water  filtered,  leaving 
thus  92  per  cent  available  for  consumption. 

The  data  upon  the  proportion  of  filtered  water  from  mechani- 


264  THE  PURIFICATION  OF   WATER. 

cal  filters  actually  available  for  consumption  is  rather  meager,  and 
some  of  that  which  we  have  not  very  exact.  Quoting  from  Mr. 
Baker's  paper  on  the  use  of  mechanical  filters  by  certain  cities  of 
New  Jersey,*  the  mechanical  filters  at  Long  Branch  require  about 
5  per  cent,  while  the  filters  at  Asbury  Park  require  about  10  per 
cent,  of  the  total  pumpage  for  washing  the  sand-beds.  At  Key- 
port,  "  Filtered  water  is  used  in  washing.  When  the  filters  had 
been  in  operation  only  some  two  months,  it  was  stated  that  15  per 
cent  of  the  water  pumped  was  required  for  washing,  but  that  the 
contractor  had  promised  to  reduce  this." 

In  a  circular  published  by  one  of  the  manufacturers  of  me- 
chanical filters,  it  is  stated  in  one  instance  that  3.97  per  cent  of 
the  total  pumpage  was  used  for  washing  the  sand-bed. 

With  the  mechanical  filters  at  Lorain,  Ohio,  it  is  stated  that 
5.22  per  cent  of  the  filtered  water  is  used  in  washing  the  sand.f 

At  Hamburg  the  water  for  sand-washing  (1896)  represented 
less  than  one  per  cent  of  the  total  delivery  by  the  filters,  while  at 
Berlin  less  than  one-half  per  cent  of  the  filtered  water  is  lost  in 
washing  the  sand  scraped  from  the  sand-beds. 

COST    OF    FILTRATION. 

The  cost  of  operating  sand  filters  abroad,  according  to  the 
statement  of  the  officials,  are  so  various  and  widely  different  as  to 
suggest  that  some  of  these  include  items  of  expense  not  necessa- 
rily connected  with  filtration  per  se,  but  which  are  embraced  in  the 
ordinary  expenses  of  water-works  operation,  while  some  are  given 
so  ridiculously  low  as  to  raise  a  suspicion  of  error  in  the  opposite 
direction. 

The  cost  per  million  gallons  of  water  treated  (not  including 
interest  and  sinking-fund  charges,  and  omitting  the  charge  for  re- 
moval of  ice)  for  the  Lawrence,  Mass.,  filters  for  1895  was  84.10  ; 
and  estimating  interest  charges  on  $65,000  at  5  per  cent,  and  sink- 
ing-fund payments  invested  at  4  per  cent  for  40  years,  the  total 
cost  per  million  gallons  for  that  year  was  §7.69.  Taking  account 

*  M.  N.  Baker,  Proceedings  New  Jersey  Sanitary  Association,  1895,  p.  84  et  seq. 
t  Ohio  Sanitary  Bulletin,  October,  1897,  p.  115. 


COST  OF  FILTERS  AND   FILTRATION.  265 

of  the  cost  of  clearing  the  filter  of  ice,  and  including  interest  and 
sinking-fund  charges,  the  total  cost  per  million  gallons  of  water 
filtered  was  $10.34. 

On  page  121  of  Mr.  Hazen's  book  on  The  Filtration  of  Pub- 
lic Water  Supplies,  the  cost  per  million  gallons  for  treatment  of 
8,000,000  gallons  per  day,  including  interest  and  sinking-fund 
charges  at  six  per  cent  (no  time  of  redemption  given),  is  esti- 
mated at  $12.50.  Omitting  interest  and  sinking-fund  charges, 
the  cost  is  figured  at  85.30.  In  his  report  to  the  Woman's 
Health  Protective  Association  of  Philadelphia,  he  puts  the  cost, 
with  previous  sedimentation,  at  $3.50  per  million  gallons  ;  while  at 
Albany,  with  preliminary  sedimentation,  he  estimates  the  cost  at 
$2.50  per  million  gallons,  and  without  preliminary  sedimentation, 
at  $3.50  per  million  gallons.  (These  prices  do  not  include  inte- 
rest and  sinking-fund  charges.) 

The  cost  of  filtration,  not  including  interest  and  sinking-fund 
charges,  at  Zurich,  is  stated  as  61  cents  for  the  covered  filters, 
and  94  cents  for  the  open  filters,  per  1,000,000  U.  S.  gallons. 
The  average  cost  for  both  open  and  closed  filters,  including  inte- 
rest and  sinking-fund  charges,  is  deduced  from  Mr.  Preller's  notes 
as  $6.71  per  million  U.  S.  gallons  filtered. 

A  very  careful  estimate  of  all  items  of  expense  entering  into 
the  operation  of  the  filters  proposed  for  Cincinnati,  with  due 
allowance  for  loss  of  sand  in  handling  and  washing,  superin- 
tendence, daily  laboratory  work,  and  depreciation  of  such  portions 
of  the  apparatus  as  is  subject  to  wear,  based  upon  60,000,000 
gallons  of  water  treated  daily,  gave  $3.50  per  million  gallons, 
exclusive  of  interest  and  sinking-fund  charges ;  although  $4.00  per 
million  gallons  was  used  in  estimating  the  probable  cost  of  filtra- 
tion in  the  report  on  these  works. 

The  cost  of  filtration  in  any  instance  (omitting  interest  and 
sinking-fund  charges)  will  depend  very  largely  upon  the  manage- 
ment of  the  filters.  In  London  the  cost  per  million  U.  S.  gallons 
ranges  from  $1.15  to  $2.00,  and  probably  averages  less  than  $1.50 
per  million  U.  S.  gallons. 

In  the  review  of  the  sand  filters  at  Poughkeepsie,  N.Y.,*  the 

*  Manual  of  American  Water  Works,  1889-90,  p.  175. 


266  THE  PURIFICATION  OF   WATER. 

cost  per  million  gallons  of  water  filtered  is  given  as  $1.32,  a  price 
which  indicates  that  these  filters  were  not  then  worked  with  a 
view  to  the  high  quality  of  filtrate  obtained  in  works  abroad. 

Investigations  during  the  present  year  (1897)  of  filter  practice 
in  one  of  the  larger  cities  of  Germany,  indicates  a  cost  there  of 
less  than  $1.20  per  million  U.  S.  gallons  of  water  filtered,  for  the 
scraping  of  the  sand-bed,  transport  of  the  sand  to  the  washers, 
washing  the  "fouled"  sand,  and  finally  returning  the  sand  to  the 
filter  bed.  This  price  would  apply  only  to  large  works,  in  which 
the  construction  of  filters  and  all  appurtenances  were  modern,  and 
when  the  management  was  the  best.  Allowing  100  per  cent  addi- 
tional for  other  labor  about  the  filters  ;  renewal  of  the  sand  lost 
in  handling  and  washing  ;  deterioration  of  barrows,  trucks,  sand- 
washers,  etc.,  and  for  supervision  ;  and  increasing  this  cost  by  50 
per  cent  for  similar  works  in  this  country,  the  cost,  not  including 
interest  and  sinking-fund  charges  on  filters  and  apparatus,  nor  re- 
pairs of  the  filters  proper,  should  not  exceed  $3.00  per  1,000,000 
gallons  of  water  passed  through  the  filters. 

Assuming  a  cost  of  $4.00  per  million  gallons  of  water  filtered, 
interest  charges  on  the  cost  of  constructing  open  filters  at  4  per 
cent,  and  payments  to  sinking-fund  for  40  years  invested  at  3<V 
per  cent,  the  total  cost  per  million  gallons  of  water  filtered  should 
not  exceed  $6.37.  Allowing  for  a  consumption  of  100  gallons 
per  capita  per  diem,  the  annual  cost  per  capita  will  be  23£  cents. 


APPENDICES. 


268 


APPENDIX  A, 


APPENDIX    A. 


TYPHOID    FEVER    STATISTICS 

OF  THE  PRINCIPAL  CITIES  OF  THE  UNITED  STATES  AND  EUROPE. 

Compiled  from  the  Official  Reports  of  Health  Departments,  January,  1897. 
DEATH   RATE   PER    1OO.OOO   OF   POPULATION   LIVING. 


City. 

Source  of  Supply. 

1890. 

POPULA- 
TION. 

DEATH 
BATE. 

New  York,  N.Y., 

Imp'd  water  from  Croton  and  Bronx  Rivers, 

1,705,980 

21 

Chicago,  111., 

Lake  Michigan, 

1,208,664 

83 

Philadelphia,  Pa., 

Schuylkill  and  Delaware  Rivers, 

1,046,964 

64 

Brooklyn,  N.  Y., 

Impounded  water  from  driven  and  open  wells, 

853,945 

26 

St.  Louis,  Mo., 

Mississippi  River, 

450,000 

34 

Boston,  Mass., 

Lake  Cochituate  and  Sudbury  River, 

437,245 

43 

Baltimore,  Md., 

Lake  Roland  and  Gunpowder  River, 

434,151 

57 

San  Francisco,  Cal., 

Impounded  water  from  mountain  streams, 

300,000 

59 

Cincinnati,  O., 

Ohio  River, 

296,000 

67 

Cleveland,  O., 

Lake  Erie, 

277,488 

66 

Buffalo,  N.  Y  , 

Niagara  River  at  head, 

New  Orleans,  La., 

Drinking-water  from  tanks  and  cisterns, 

254,000 

20 

Washington,  D.  C., 

Potomac  River, 

250,000 

83 

Pittsburg,  Pa  , 

Alleghany  River, 

.  .  . 

Detroit,  Mich., 

Detroit  River, 

230,000 

18 

Milwaukee,  Wis., 

Lake  Michigan, 

220,000 

33 

Newark,  N.  J.,  * 

Impounded  water,  Pequannock  River, 

181,830 

60 

Jersey  City,  N.  J  , 

Passaic  and  Pequannock  Rivers, 

163,003 

91 

Louisville,  Ky., 

Ohio  River, 

161,000 

88 

Providence,  R.I., 

Pawtucket  River, 

132,146 

29 

Indianapolis,  Ind., 

Driven  wells  and  Filter  Gallery, 

.  .  . 

Lowell,  Mass  , 

Merrimac  River  and  driven  wells, 

77,696 

158 

Lawrence,  Mass., 

Filtered  from  Merrimac  River, 

44,654 

123 

Nashville,  Tenn., 

Filter  gallery,  Cumberland  River, 

77,000 

46 

Dayton,  O., 

Driven  wells, 

60,000 

20 

Covington,  Ky  , 

Ohio  River, 

37,400 

43 

Newport,  Ky.,t 

Ohio  River, 

Denver,  Col., 

South  Platte  River  and  Marston  Lake, 

.  .  . 

Atlanta,  Ga., 

Mechanical  filter,  Chattahootchie  River, 

65,533 

151 

Chattanooga,  Tenn., 

Mechanical  filter,  Tennessee  River, 

29,109 

145 

Knoxville,  Tenn.,$ 

Mechanical  filter,  Tennessee  River, 

40,600 

101 

Quincy,  111., 

Mechanical  filter,  Mississippi  River, 

31,500 

83 

Davenport,  la., 

Mechanical  filter,  Mississippi  River, 

30,000 

50 

Montreal,  Que., 

St.  Lawrence  River, 

216,300 

29 

Toronto,  Ortt., 

Lake  Ontario, 

167,439 

93 

East  Jersey  Water  Co.,  Estab.  April  15,  1892. 


t  Health  Department,  Estab.  1893. 


APPENDIX  A. 


269 


APPENDIX     A. 


TYPHOID    FEVER    STATISTICS 

OF  THE  PRINCIPAL  CITIES  OF  THE  UNITED  STATES  AND  EUROPE. 

Compiled  from  the  Official  Reports  of  Health  Departments,  January,  1897. 
DEATH   RATE   PER    1OO.OOO   OF   POPULATION  LIVING. 


1891. 

1892. 

1993. 

1894. 

1895. 

1896. 

POPULA- 
TION. 

DEATH 
BATE. 

POPULA- 
TION. 

DEATH 
BATE. 

POPULA- 
TION. 

1>EATH 
BATE. 

POPULA- 
TION. 

DEATH 
BATE. 

POPULA- 
TION. 

DEATH 
BATE.  | 
1 

POPULA- 
TION. 

=  _ 
<£ 
8S 

1,765,645 

22 

1,827,396 

22 

1,891,306 

20 

1,957,452 

17 

1,879,195 

17 

1,934,077 

16 

1,250,000 

160 

1,438,010 

104 

1,600,000 

42 

1,567,727 

31 

1,600,000 

32 

1,619,226 

46 

1,069,264 

64 

1,092,168 

40 

1,115,562 

41 

1,146,000 

32 

1,163,864 

40 

1,188,793 

34 

880,780 

20 

962,530 

17 

990,891 

17 

1,045,000 

15 

1,090,000 

16 

1,140,000 

15 

452,000 

30 

460,000 

37 

500,000 

103 

540,000 

31 

560,000 

19 

570,000 

19 

461,093 

33 

474,063 

29 

487,397 

30 

•    501,107 

28 

496,920 

33 

508,694 

32 

445,853 

34 

458,350 

42 

473,193 

47 

455,427 

49 

496,315 

39 

507,398 

37 

330,000 

41 

330,000 

34 

330,000 

32 

330,000 

35 

330,000 

37 

330,000 

31 

300,000 

62 

305,000 

40 

310,000 

43 

336,000 

50 

336,000 

36 

341,000 

48 

299,475 

52 

309,243 

54 

322,932 

47 

325,000 

27 

325,000 

36 

330,279 

43 

255,664 

50 

285,000 

34 

300,000 

37 

315,000 

36 

335,709 

29 

350,000 

20 

254,000 

23 

254,000 

21 

254,000 

15 

275,000 

28 

275,000 

41 

275,000 

33 

250,000 

83 

260,000 

70 

285,000 

66 

270,514 

71 

271,000 

74 

278,150 

51 

247,000 

100 

255,000 

100 

264,000 

111 

272,000 

56 

275,000 

77 

280,000 

61 

230,000 

13 

230,000 

51 

230,000 

61 

250,000 

26 

280,000 

22 

279,000 

20 

233,333 

33 

245,000 

31 

260,000 

37 

267,500 

26 

260,000 

27 

257,500 

18 

187,108 

81 

192,531 

45 

198,115 

28 

203,861 

15 

215,725 

17 

230,000 

21 

167,237 

95 

171,471 

53 

175,000 

60 

179,939 

76 

184,173 

71 

187,098 

61-62 

161,000 

81 

161,000 

72 

161,000 

84 

200,000 

72 

205,000 

77 

211,100 

45 

132,146 

47 

132,146 

39 

148,944 

34 

153,000 

47 

145,472 

32 

150,000 

27 

120,000 

36 

125,000 

52 

125,000 

106 

125,000 

55 

125,000 

97 

165,000 

41 

80,400 

98 

83,200 

90 

87,191 

61 

90,613 

55 

84,367 

39 

85,700 

42 

45,911 

115 

47,204 

102 

48,355 

93 

49,900 

48 

52,164 

31 

55,000 

15 

80,000 

56 

83,000 

53 

85,000 

24 

87,000 

32 

87,500 

47 

87,754 

55 

60,000 

32 

63,000 

44 

75,000 

64 

85,000 

20 

80,000 

47 

85,000 

25 

40,000 

45 

42,500 

40 

45,000 

27 

48,000 

42 

48,000 

27 

50,000 

32 

120,000 
85,000 

53 

87 

27,500 
125,000 
95,000 

58 
57 
66 

30,000 
140,000 
108,000 

37 
35 
43 

30,000 
145,000 
100,000 

73 
30 
70 

30,000 
150,000 
110,000 

63 
61 
60 

75,000 

119 

34,900 

06 

40,000 

55 

36,000 

86 

35,751 

48 

40,000 

47-48 

40,000 

30 

40,385 

45 

40,385 

37 

40,385 

67 

40,385 

59 

(  »  37,000 
M    8,000 

32 
125 

34,000 

32 

36,000 

50 

37,500 

48 

39,000 

77 

40,500 

59 

42,000 

26 

30,000 

30 

30,600 

16 

30,900 

35 

34,000 

18 

,     35,000 

31 

35,000 

20 

218,268 

30 

224,816 

22 

231,560 

21 

241,748 

17 

249,000 

18 

256,470 

21 

181,220 

94 

184,000 

43 

188,333 

42 

196,666 

17 

196,666 

28 

196,666 

28-29 

J  (1)  City  proper;  (2)  Suburbs. 


270 


APPENDIX  A. 


APPENDIX   ^.  —  Continued. 


DEATH   RATE   PER    1OO,OOO   OF  POPULATION   LIVING. 


City. 

Source  of  Supply. 

1890. 

POPULA- 
TION. 

DKATH 
BATE. 

London,  Eng., 

From  Kent  wells  and  filtered  water  from  the 

Rivers  Thames  and  Lea, 

4,180,654 

16 

Liverpool,  Eng., 

Lake  Vyrnwy  (Wales), 

513,493 

24 

Manchester,  Eng., 

Lake  Thirlmere  (Cumberland), 

379,437 

31 

Edinburgh,  Scot., 

Impounded  water,  Pentland  Hills, 

271,135 

19 

Glasgow,  Scot., 

Loch  Katrine, 

530,208 

26 

Dublin,  Ire., 

Impounded  water  filtered  from  River  Vartry, 

353,082 

62 

Paris,  Fr., 

Ourcq   Canal,  artesian  wells,  springs,  Rivers 

Seine,  Marne,  and  Vanne, 

2,260,945 

30 

Brussels  (with  suburbs),  Bel., 

477,288 

26 

Amsterdam,  Hoi., 

Haarlem  dunes, 

406,302 

19 

Rotterdam,  Hoi., 

Filtered  water  from  River  Mass, 

203,486 

6 

The  Hague,  Hoi., 

From  sand  dunes, 

156,497 

3 

Copenhagen,  Den., 

Driven  wells, 

312,387 

9 

Stockholm,  Sweden, 

Lake  and  well  water, 

236,350 

18 

Christiania,  Nor., 

143,300 

12 

St.  Petersburg,  Rus., 

Filtered  water  from  River  Neva, 

842,000 

57. 

Moscow,  Rus., 

Mytschia   springs   and    ponds,    Moscov    and 

Yanza  Rivers, 

753,469 

73 

Berlin,  Ger., 

Filtered   water  from  Lake  Tegel  and   River 

Spree, 

1,548,279 

9 

Hamburg  (State),  Ger., 

Filtered  water  from  River  Elbe, 

591,647 

28 

Altona,  Ger., 

Filtered  water  from  River  Elbe, 

143,249 

19 

Dresden,  Ger., 

Filter  gallery  by  River  Elbe, 

269,250 

9 

Breslau,  Ger., 

Filtered  water  from  River  Oder, 

324,400 

15 

Munich,  Ger., 

Spring  water  from  Mangfall  Valley, 

298,000 

8 

Vienna  (with  suburbs),  Aust-Hung. 

Springs  in  the  Schneeberg  and  driven  wells, 

822,176 

9 

Prague,  Aust.-Hung., 

314,425 

33 

Budapest,  Aust.-Hung., 

Ground  water  from  wells, 

463,017 

34 

Trieste,  Aust.-Hung., 

160,092 

12 

Rome,  Italy, 

Fontanadi  Trevi,  Aqua  Felice,  and  Paoli, 

417,392 

35 

Milan,  Italy, 

Turin,  Italy, 

314,827 

46 

Venice,  Italy, 

Springs  in  the  mountains  fifteen  miles  distant, 

—  cast-iron  conduit. 

156,800 

44 

Cairo,  Egypt,* 

River  Nile  by  canal, 

374,838 

260 

Alexandria,  Egypt,* 

River  Nile  by  canal, 

231,396 

208 

Sydney  (with  suburbs),  Austr., 

Impounded  water  from  Upper  Nepean  River, 

Brisbane  (with  suburbs),  Austr., 

Including  malarial  fevers. 


APPENDIX  A, 


271 


A  P PE N  D I X  •  A.  —  Continued. 


DEATH   RATE   PER    1OO.OOO   OF  POPULATION   LIVING. 


1891. 

1892. 

1893 

1894. 

1895. 

1896. 

POPULA- 
TION. 

DEATH 
KATE. 

POPULA- 
TION. 

DEATH 
RATE. 

POPULA- 
TION. 

DEATH 
RATE. 

POPULA- 
TION. 

DEATH 
RATE. 

POPULA- 
TION. 

% 

POPULA- 
TION. 

IS 

4,222,157 

15 

4,264,076 

11 

4,306,411 

16 

4,349,166 

15 

4,392,346 

14 

4,421,955 

14 

517,116 

25 

513,790 

25 

510,514 

53 

507,230 

58 

503,967 

37 

632,512 

32 

506,469 

39 

510,998 

25 

515,598 

25 

520,211 

18 

524,865 

19 

529,561 

23 

261,970 

18 

264,787 

13 

267,261 

14 

270,588 

15 

273,535 

20 

276,514 

16 

567,143 

31 

669,059 

18 

677,883 

20 

686,820 

24 

695,876 

19 

705,052 

23 

347,312 

58 

349,594 

39 

349,594 

87 

349,594 

48 

349,594 

27 

349,594 

45 

2,424,705 

20 

2,424,705 

28 

2,424,705 

25 

2,424,705 

29 

2,424,705 

11 

2,511,629 

11 

465,517 

41 

476,862 

23 

488,188 

27 

498,400 

14 

507,985 

16 

518,3£7 

18 

417,539 

11 

426,914 

15 

437,892 

16 

446,295 

8-9 

451,493 

11 

489,496 

3 

209,136 

4 

216,679 

6 

222,233 

5 

228,597 

5 

272,042 

2 

276,338 

12 

.  160,531 

12 

165,560 

4 

169,828 

2 

174,790 

3 

180,455 

5 

187,545 

4 

320,000 

8 

330,000 

7 

337,500 

9 

341,000 

7 

333,714 

16 

333,714 

7 

245,317 

18 

248,051 

19 

249,246 

8 

252,937 

8 

259,304 

9 

267,100 

6 

151,130 

9 

156,535 

4 

161,151 

6 

167,588 

3 

174,717 

7 

182,856 

33 

•• 

954,400 

51 

954,400 

49 

954,400 

87 

954,400 

142 

753,469 

75 

753,469 

68 

753,469 

40 

753,469 

29 

753,469 

50 

753,469 

46 

1,601,327 

10 

1,662,237 

8 

1,714,938 

9 

1,701,643 

4 

1,734,492 

5 

1,695,313 

5 

622,530 

23 

637,686 

34 

634,878 

18 

598,372 

6 

608,710 

9 

625,552 

6 

144,388 

64 

145,527 

43 

146,667 

15 

147,807 

7 

148,934 

13 

.  .  . 

276,523 

8 

301,400 

5 

308,930 

4-5 

316,600 

8 

324,341 

5 

342,340 

4 

339,000 

12 

346,442 

15 

353,551 

10 

360,660 

6 

367,769 

9 

377,062 

8 

357,000 

7 

373,000 

3 

385,000 

15 

393,000 

2-3 

396,000 

3 

406,000 

3 

1,378,530 

6 

1,406,933 

8 

1,435,931 

7 

1,465,537 

5 

1,495,764 

6 

1,526,623 

5 

310,485 

37 

321,167 

53 

327,953 

36 

339,172 

57 

351,478 

46 

364,632 

28 

513,010 

23 

526,263 

26 

539,516 

15 

552,769 

14 

566,022 

20 

579,275 

29 

156,190 

11 

157,343 

26 

158,314 

17 

159,739 

19 

160,825 

5 

161,886 

13 

427,684 

36 

438,123 

26 

449,430 

34 

456,777 

30 

465,563 

62 

473,296 

27 

424,887 

62 

430,829 

62 

.  .  . 

441,948 

55 

320,808 

41 

329,724 

44 

334,090 

29 

335,957 

24 

344,203 

32 

344,203 

24 

158,288 

33 

162,664 

30 

163,601 

26 

158,187 

18 

158,159 

23 

163,254 

27 

374,838 

235 

374,838 

163 

374,838 

154 

374,838 

135 

374,838 

90 

374,838 

141 

231,396 

348 

231,396 
406,480 

77 
20 

231,396 
411,710 
93,657 

79 
19 
19 

231,396 
421,030 
93,657 

100 
29 
10 

231,396 
423,600 
93,657 

103 
20 
60 

231,396 

89 

APPENDIX    B.* 


THE    BACTERIA. 

THE  bacteria  are  minute  vegetable  organisms,  devoid  of  chlorophyl, 
and  consist  of  a  cellulose  envelope  containing  a  protoplasm  described 
as  mycoprotein. 

According  to  Nencki  t  they  have  the  following  chemical  composi- 
tion :  — 

Water,  84.26  per  cent. 

Solids,  15.74   "      " 

100.00  per  cent. 

Of  the  solids  Nencki  finds  for  the  putrefactive  bacteria  of:  — 

Albumen,  87.46  per  cent. 

Fat,  6.41    "      " 

Ash,  3.04   «      " 

Undetermined  substances,  3.09    "       " 

100.00  per  cent. 

"  The  albuminous  substance  is  not  precipitated  by  alcohol,  and 
differs  in  its  chemical  composition  from  other  known  substances  of  its 
class." 

Nencki  calls  this  substance  mycoprotein,  and  gives  the  following  as 
its  chemical  composition  :  — 

Carbon,  52.32 

Hydrogen,  7.55 

Nitrogen,  14.75 

*  This  Appendix  is  written  with  reference  solely  to  water  purification,  and  is  intended 
only  as  a  brief  discussion  of  the  bacteria.  Those  who  may  desire  to  pursue  the  inquiry  further 
are  referred  to  the  standard  text-books  on  this  subject,  of  which  may  be  mentioned,  A  "Manual 
of  Bacteriology,  by  Dr.  George  M.  Sternberg,  New  York,  1893;  The  Principles  of  Bacteriology, 
by  Dr.  A.  C.  Abbott,  Philadelphia,  1894 ;  Micro  Organisms  tn  Water,  by  P.  F.  &  G.  C.  Frank- 
land,  London,  1894 ;  Bacteriological  Diagnosis,  by  Dr.  James  Eisenberg,  Philadelphia,  1892 ; 
The  Pathogenic  Bacteria,  by  Dr.  Joseph  McFarland,  Philadelphia,  1896,  etc. 

t  A  Manual  of  Bacteriology,  by  Dr.  George  M.  Sternberg,  New  York,  1893,  p.  117. 

272 


APPENDIX  B.  273 

% 
Mycoprotein  contains  neither  phosphorus  nor  sulphur. 

The  nitrogenous  body  appears  to  vary  in  different  species,  for  in 
b.  anthracis  a  substance  has  been  obtained  by  Nencki  which  does  not 
give  the  reactions  of  mycoprotein.  This  substance  he  calls  anthrax- 
protein.* 

The  green  coloring-matter  of  plants  is  known  as  chlorophyl,  and  the 
absence  of  this  substance  in  the  bacteria  compels  them  to  obtain  the 
materials  upon  which  they  subsist  from  organic  matter  in  process  of 
digestion  or  decomposition  ;  in  fact,  the  destruction  and  splitting  up 
of  organic  matter  into  its  constituent  elements,  is  chiefly,  and  in  some 
cases  wholly,  due  to  bacterial  agencies. 

The  production  of  carbon  dioxide,  carbon  monoxide,  and  nitrous  and 
nitric  acids  from  decomposing  organic  matter,  is  due  to  the  action  of 
the  bacteria.  The  putrefactive  bacteria  are  the  first  to  attack  organic 
matter,  producing  what  is  known  as  decay,  with  a  liberation  of  carbonic 
acid  and  other  gases,  while  the  nitrifiers  discovered  by  Winogradsky  in 
the  soil  at  Zurich,  act  upon  the  nitrogenous  matters,  and  convert  them 
into  nitrous  and  nitric  acids,  which,  uniting  with  lime,  sodium,  potash, 
or  other  bases,  form  the  nitrites  and  nitrates  for  the  support  of  plant 
life. 

SAPROPHYTES    AND    PARASITES. 

The  bacteria  divide  into  two  great  classes  :  — 

1.  Those  which  live  and  propagate  their  kind  only  upon  dead  or- 
ganic matter,  and  known  as  the  saprophytes. 

2.  Those  which  will  live  and  develop  only  in  the  tissues  or  fluids  of 
the  living  body,  and  known  as  the  parasites. 

The  line  of  division  between  the  two  classes  is  not  well  marked. 
Some  of  the  saprophytes  may,  under  certain  conditions,  flourish  as  para- 
sites ;  while  certain  of  the  parasites,  known  to  attain  their  highest  state 
of  development  in  the  animal  body,  will  live  for  a  limited  time  as  sapro- 
phytes. Thus  the  bacillus  of  tuberculosis  (consumption)  is  classed  as  a 
true  parasite,  but  it  can  be  cultivated  (on  artificial  media)  outside  the 
living  host ;  while  some  of  the  so-called  saprophytes  may  independently, 
or  in  conjunction  with  certain  of  the  pathogenic  bacteria,  be  responsible 
for  processes  in  the  animal  body  which  result  in  disease,  and  should 
therefore  be  regarded  as  facultative  parasites. 

Bacteria  which  cannot  subsist  upon  living  matter  are  strict  sapro- 
phytes, while  those  which  cannot  subsist  upon  dead  matter  are  true 
parasites ;  but  the  dividing  line  i.j  not  so  distinct  that  we  can  readily 

*  A  Manual  of  Bacteriology,  by  E.  M.  Crookshank,  London,  1890,  p.  148. 


274  APPENDIX  B. 

determine  with  regard  to  certain  bacteria  whether  they  are  the  one  or 
the  other  ;  and  a  saprophyte  may  be  •&.  facultative  parasite,  while  a  parasite 
may  be  a  facultative  saprophyte. 

LIQUEFIERS    AND    NON-LIQUEFIERS. 

The  bacteria  again  divide  into  two  other  great  classes :  — 

1.  Those  which  when  cultivated  in  gelatin  will  render  it  fluid,  and 
known  as  the  liquefiers. 

2.  Those  which  will  develop  on  or  in  gelatin  without  liquefaction, 
and  known  as  the  uon-liquefiers. 

The  bacillus  of  typhoid  fever  will  not  liquefy  gelatin,  while  the  bacil- 
lus of  cholera  does  liquefy  gelatin.  Most  of  the  pathogenic  or  disease- 
producing  bacteria  are  uon-liquefiers,  while  most  of  the  putrefactive  bac- 
teria are  rapid  liquefiers.  Certain  of  the  bacteria  will  liquefy  gelatin  at 
room  temperature  (70°  Fahr.)  within  a  day  or  two,  while  others  require 
a  growth  of  two  or  three  weeks  to  render  the  gelatin  fluid,  and  some 
reduce  the  solid  gelatin  to  a  fluid  at  a  rate  so  slow  that  the  water  of 
liquefaction  is  evaporated  through  the  cotton  plug  of  the  test-tube  as 
rapidly  as  it  is  formed. 

The  liquefaction  of  gelatin  by  bacterial  agencies  is  not  due  to  the 
production  of  heat  in  the  destruction  of  organic  matter,  but  to  certain 
somewhat  indistinct  changes,  by  which  the  gelatin  is  peptonized  and 
rendered  incapable  of  again  becoming  hard  at  the  temperature  of  melt- 
ing ice  (32°  Fahr.). 

AEROBIANS    AND    ANAEROBIANS. 

Again,  the  bacteria  divide  into  two  other  great  classes  as  defined  by 
Pasteur  :  — 

1.  Those   which  will   grow   only  in   the   presence   of   oxygen,  and 
termed  aerobians. 

2.  Those  which  will  not  grow  in  the  presence  of  oxygen,  and  termed 
anae'robians. 

Most  of  the  bacteria,  so  far  as  we  are  now  aware,  are  aerobians  ; 
but  it  is  probable  that  plate  cultivation  under  strictly  anaerobic  condi- 
tions may  demonstrate  the  existence  of  species  now  unsuspected  which 
will  not  grow  in  the  presence  of  oxygen.  For  example,  the  bacteria 
found  upon  cultivation  of  a  sample  of  water  in  a  Petri  dish,  or  on  a 
plate,  are  all  aerobians,  while  the  bacillus  of  tetanus  (lockjaw)  is  a  true 
anaerobian.  Under  the  usual  conditions  of  plate  culture  the  anaerobic 
species,  if  any  are  in  the  water  or  other  sample,  will  not  grow,  and  of 


APPENDIX  B.  275 

course  do  not  enter  into  the  subsequent  count  of  the  colonies,  nor  into 
the  differentiation  of  species  found  on  the  plate. 

The  plugging  of  the  glass  test-tubes  for  culture  media  with  cotton, 
allows  the  air  to  pass  freely  into  the  tube,  while  it  effectually  prevents 
the  entrance  of  any  organism  in  the  air,  however  small  it  may  be. 

Naturally,  because  of  the  difficulties  of  cultivation,  few  anaerobic 
species  of  the  bacteria  have  been  found  in  water,  but  with  improved 
and  more  convenient  methods  of  (anaerobic)  cultivation,  more  may  in 
the  future  be  found. 

FORMS    OF    THE    BACTERIA. 

The  bacteria  are  seen  to  be  of  three  general  forms  when  examined 
under  the  microscope. 

1.  The  Cocci,  or  spherical  forms,  which  for  convenience  of  identifica- 
tion are  divided  into  :  — 

The  Micrococci,  when  the  spheres  are  single  or  in  irregular  groups. 

The  Diplococci,  consisting  always  or  occasionally  of  two  spheres 
joined,  and  resembling  a  dumb-bell  with  the  connecting  rod  missing. 

The  Tetrads,  which  consist  of  triangular  groups  of  three  of  the 
spheres,  or  cocci. 

The  Streptococci,  in  which  the  spheres  are  found  in  chains  of  many 
members. 

The  Staphylococci,  in  which  the  spheres,  or  cocci,  are  grouped  some- 
what like  bunches  of  grapes.  (To  this  class  belong  the  yellow  and 
white  germs  of  septicaemia,  or  blood  poisoning.) 

The  Sarciiia,  in  which  the  spheres  are  found  in  cubical  packets, 
divided  in  three  directions,  like  a  bale  of  goods  tied  with  cords  parallel 
to  all  the  sides. 

The  sarcina  contain  8  or  more  spheres.  Thus,  if  divided  once  in 
each  direction,  the  packet  will  contain  the  cube  of  two,  or  8  spheres ;  if 
divided  twice  in  each  direction,  the  packet  will  contain  the  cube  of 
three,  or  27  spheres.  Usually  the  sarcina  are  seen  under  the  microscope 
as  broken  packets,  the  preparation  and  fixing  of  the  culture  on  the 
cover  glass  breaking  up  the  characteristic  arrangement  of  the  members. 

The  cocci  are  regarded  as  non-spore-bearing  bacteria. 

2.  The  bacilli,  or  rods,  straight  or  slightly  bent. 

To  this  class  belong  the  organisms  b.  typhosus,  diphtheria,  c'oli  corn- 
munis,  lactis  aerogenes,  the  tubercle  bacillus,  and  nearly  all  the  putrefac- 
tive and  pathogenic  bacteria. 

The  bacilli  grow  into  rods,  and  separate  into  individual  cells  by 


276  APPENDIX  B. 

fission.  Thus  one  rod  becomes  two  rods  by  separation  in  the  middle  ; 
each  of  these  separates  again  ;  and  as  an  evidence  of  the  rate  of  growth 
and  multiplication  of  some  of  the  bacteria,  it  is  stated  that  one  rod  or 
cell  may,  under  favorable  conditions,  grow  and  divide  within  twenty 
minutes ;  from  which,  by  calculation,  it  will  be  seen  that  one  rod  may 
become  the  parent  of  nearly  17,000,000  within  twenty-four  hours.* 

Of  the  bacilli,  most  are  straight  rods  with  round  ends.  B.  anthratis 
is  a  straight  rod  with  square  ends  united  in  chains.  In  young  cultures 
of  the  typhoid  germ  long  crooked  strings  are  frequently  noticed ;  these 
strings,  or  filaments,  consist  of  many  bacilli  united  together.  In  due 
time  such  strings,  by  fission,  separate  into  the  typical  bacilli  of  varying 
length.  The  manner  in  which  the  bacilli  are  displayed  on  a  cover  glass 
preparation  is  an  important  number  in  the  differentiation  of  species. 
Thus  certain  kinds,  like  b.  anthracis,  always  are  found  in  well-defined  long 
chains,  with  some  detached  links  or  rods  (probably  broken  from  the  chain 
by  the  manipulation  of  the  specimen  on  the  cover  glass)  ;  others  occur 
only  as  separate  rods  ;  sometimes  short  chains,  of  two  to  six  or  eight  rods, 
constitute  the  manner  of  grouping,  but  in  all  cases  there  is  a  method  of 
grouping  which  is  a  property  or  characteristic  of  the  species. 

3.  The  spirilla,  or  vibrios,  are  rods  always  bent,  sometimes  in  the 
form  of  the  letter  "  S."  To  this  class  belongs  the  comma  bacillus  of  Koch, 
known  as  the  cholera  germ.  As  a  rule,  the  spirilla  are  rods  which, 
if  measured  on  the  curve,  are  longer  than  the  bacilli ;  or  the  bacilli 
and  spirilla  may  both  be  regarded  as  rod  forms  of  the  bacteria,  the 
bacilli  usually  being  the  shorter  and  straight  rods,  while  the  spirilla  are 
the  longer  and  always  bent  or  crooked  rods.  The  germ  of  diphtheria  is 
a  comparatively  long,  slightly  bent  rod,  but  is  classed  as  a  bacillus. 

The  spirilla  found  in  water  are  much  fewer  in  number  of  kinds  than 
the  bacilli ;  in  fact,  the  majority  of  the  bacteria  found  in  polluted  waters 
are  of  the  latter  form. 


MOTILITY    OF    THE    BACTERIA. 

A  property  of  the  bacilli  and  spirilla,  the  cause  of  which  is  still  open 
to  investigation,  is  motility.  Certain  of  the  bacteria  of  these  forms 
when  examined,  stained  or  unstained  in  drop  cultures,  exhibit  surprising 
activity.  Thus  the  germ  b.  typhosus  (in  a  drop  of  bouillon)  has  motions 
of  translation  and  rotation,  and  sinuous  movements  like  a  snake.  Occa- 
sionally some  of  the  rods,  when  taken  from  young  cultures,  will  be 

*  A  Manual  of  Bacteriology,  by  Dr.  George  M.  Sternberg,  p.  114. 


APPENDIX  B.  277 

observed  in  rotation  resembling  the  movement  of  am  acrobat  on  a  hori- 
zontal turning-bar,  while  others  have  a  sluggish  or  no  motion  at  all. 
B.  fluorescens  Uquefaricns,  a  bacterium  frequently  found  in  water,  re- 
sembles in  motility  b.  typhosus ;  it  resembles  also  the  smaller  rods  of 
this  germ  in  dimensions ;  but  unlike  b.  typkosus,  it  rapidly  liquefies  the 
gelatin  in  which  it  is  grown,  and  in  gelatin,  and  especially  upon  agar, 
produces  a  beautiful  fluorescent  green  which  permeates  the  whole  cul- 
ture material. 

B.  coli  communis  has  motility,  but  the  motions  of  the  bacillus  are 
sluggish  and  unlike  those  of  b.  typhosus.  B.  lactis  aerogenes  is  not  pos- 
sessed of  motility. 

Motility  of  the  bacteria,  when  viewed  in  drop  cultures,  is  not  to  be 
confounded  with  pedesis,  which  is  a  swaying  or  oscillatory  motion  of  the 
organism  not  due  to  inherent  powers  of  locomotion.  The  motile  bacilli 
and  spirilla  are  provided  with  delicate  flagella  or  hair-like  appendages, 
which,  acting  as  whips  or  oars,  propel  the  germ  through  the  drop  of 
fluid  on  the  cover  glass.  It  was  at  one  time  supposed  that  the  motility 
of  the  bacilli  bore  some  relation  to  the  number  of  the  flagella,  but  re- 
cent investigations  seem  to  negative  this  belief.* 

In  Germany  the  flagella  have  been  regarded  as  an  important  ele- 
ment in  the  differentiation  of  the  bacteria,  but  according  to  Dr.  V.  A. 
Moore,  the  flagella  cannot  be  taken  into  serious  consideration  in  the 
differentiation  of  closely  allied  species. f 

With  reference  to  the  form,  size,  and  other  features  of  the  bacteria, 
due  allowance  must  be  made  for  the  environment  of  the  culture.  The 
culture  media,  its  reaction,  temperature  of  incubator,  and  nearness  of 
the  culture  to  its  original  source,  all  have  an  important  bearing  on  the 
differentiation  of  species.  When  the  bacteria  are  grown  in  a  Petri  dish, 
room  temperature  (about  70°  Fahr.)  is  preferable  as  corresponding  with 
the  conditions  under  which  the  largest  and  most  rapid  growth  will  be 
obtained;  but  at  room  temperature  most  of  the  pathogenic  bacteria  de- 
velop slowly,  and  even  if  such  were  in  a  water  sample,  the  probability  of 
finding  them  in  plate  cultures  is  rather  remote. 

CHROMOGENIC    SPECIES. 

Certain  of  the  bacteria  when  grown  upon  suitable  materials  elab- 
orate beautiful  colors,  which  rival  the  colors  of  the  solar  spectrum. 
For  example,  b.  prodigiosus,  a  bacillus  found  in  water,  produces  a  deep 
blood  red ;  b.  rothe,  another  water  bacillus,  produces  a  raspberry  red ; 

*  Character  of  the  Flagella,  V.  A.  Moore,  Washington,  D.C.,  1893.          t    Ibid.,  P-  363. 


278  APPENDIX  B. 

b.  violaceus,  also  a  water  bacillus,  produces  a  purple  merging  into  blue ; 
the  staphylococcus  pyogenes  aureus,  the  organism  of  malignant  pustule  or 
septicaemia,  found  in  water,  produces  a  golden  yellow ;  b.  proteus  fluo- 
rescens  produces  a  fluorescent  green ;  m.  candicans,  a  water  germ,  pro- 
duces a  dazzling  Chinese  white ;  m.  aurantiacus,  another  water  germ, 
elaborates  a  beautiful  orange  color ;  and  m.  carneus,  a  water  micrococci, 
produces  a  delicate  pink  or  flesh  color  when  grown  on  agar.  The  color, 
when  a  characteristic,  is  an  important  element  in  determining  species. 

Among  the  products  of  bacterial  action  on  dead  organic  matter  are 
the  ptomains,  some  of  which  have  toxic  properties.  The  substance  iso- 
lated by  Dr.  V.  C.  Vaughan  *  from  ice-cream  and  cheese,  called  tyrotoxi- 
con,  is  one  of  the  vital  products  of  the  putrefactive  bacteria.  Whether 
the  putrefactive  bacteria  are  capable  of  producing  ptomains  from  the 
organic  matter  in  water  is  not  known,  but  some  of  the  investigators 
abroad  seem  to  suspect  the  possibility  of  it. 

The  action  of  the  pathogenic  bacteria  on  organic  matter  is  the  pro- 
duction of  toxins,  which  probably  are  absorbed  into  the  circulation  of 
the  animal  with  the  symptoms  during  life  characteristic  of  specific  dis- 
ease, and  the  pathological  lesions  usually  found  upon  post-mortem  ex- 
amination. The  toxin  from  the  growth  of  the  bacillus  of  diphtheria  on 
the  mucous  membrane  of  the  fauces,  when  taken  into  the  circulation, 
produces  the  symptoms  and  lesions  characteristic  of  this  disease.  Dr. 
McFarland  remarks  upon  the  virulent  properties  of  the  toxin  elaborated 
by  the  diphtheria  bacillus,^  "  No  more  convincing  proof  of  the  existence 
of  a  powerful  poison  in  diphtheria  could  be  desired  than  the  evidences 
of  general  toxaemia,  resulting  from  the  absorption  of  material  from  a 
comparatively  small  number  of  bacilli  situated  upon  a  little  patch  of 
mucous  membrane." 

DIMENSIONS    OF    THE    BACTERIA. 

The  dimensions  of  the  bacteria  are  stated  in  microns,  designated 
by  the  Greek  letter  "  //,,"  which  is  T<jW  °f  a  millimeter,  equal  to  about 
5_i^_  of  an  inch.  Thus  the  typical  dimensions  of  b.  typhosus  are  .5  to  .8 
"/A"  wide,  by  1.5  to  2.5  "/A"  long;  or  about  s^oo  to  57550  of  an  mc^ 
wide  or  thick,  and  TF^ff  to  TTT^<j  of  an  inch  long. 

Taking  the  average  length  of  the  typhoid  bacillus  as  2  microns  (/x), 
it  will  be  seen  that  it  would  require  12,500  of  these  little  rods  placed 
end  to  end  to  make  one  inch.  The  human  mind  can  scarcely  grasp  the 

*   The  Ptomaines  and  Leucomaines.  by  Vaughan  and  Novy,  Philadelphia,  1891,  p.  35  et  seq. 
|  A  Treatise  on  the  Pathogenic  Bacteria,  Dr.  Joseph  McFarland,  Philadelphia,  1896,  p.  227. 


APPENDIX  B.  279 

smallness  of  the  bacteria ;  but  assuming  that  the  un&ided  vision  is  capa- 
ble of  distinguishing  200  lines  or  divisions  to  the  inch,  then  each  of 
such  divisions  would  contain  over  60  of  the  typhoid  germs,  placed  end 
to  end,  or  180  if  placed  side  by  side. 

The  air  and  soil  both  contain  bacteria  which  may  come  into  water, 
and  aside  from  the  pathogenic  species,  all  bacteria  found  in  water  must 
not  be  regarded  as  indigenous  to  this  source.  The  natural  water  bacte- 
ria may  be  considered  as  those  found  in  the  water  from  deep  wells  after 
the  rainfall  has  percolated  through  many  feet  of  various  kinds  of  soil 
and  filtering  material,  and  even  these  may  be,  and  probably  are,  from 
extraneous  sources;  but  for  the  present  purpose  it  may  be  held  that 
such  belong  to  water  because  of  the  inability  of  the  filtering  materials 
in  the  drift  and  rock  to  restrain  them. 

Rain  is  probably  free  from  bacteria  and  organic  matter  as  it  falls 
from  the  clouds ;  but  in  falling,  material  suspended  in  the  atmosphere 
will  be  intercepted  and  carried  down  to  the  earth,  and  into  the  usual 
receptacles  or  channels  of  discharge  of  rainfall.  In  addition  to  the 
bacteria  and  organic  matter  from  the  air,  bacteria  and  matter  from  the 
soil  is  washed  into  the  streams  and  lakes  ;  and  the  excess  in  numbers 
and  gain  in  species  of  bacteria  in  river  or  lake  waters,  over  those  in 
deep  well  waters,  may  be  attributed  to  the  air  and  soil,  or  to  sewage 
pollution.  Any  bacteria  naturally  in  the  air  will  be  intercepted  by  rain- 
fall;  and  if  the  species  are  capable  of  an  independent  existence  in 
water,  may  upon  examination  be  found  there.  Likewise  storm  water 
discharged  through  natural  channels  will  contain  bacteria  intercepted  in 
flowing  over  the  ground,  together  with  some  species  obtained  from 
erosion  of  the  earthy  banks. 

In  the  examination  of  a  water  sample  for  bacteria,  a  large  number, 
or  rapidly  liquefying  organisms,  should  suggest  the  probable  presence 
of  the  putrefactive  germs,  among  which  are  often  found  b.  proteus  vul- 
garis,  b.  meseutericus  vulgatus,  and  others  of  like  character,  which  usually 
are  held  to  come  into  water  from  sewage  sources. 

SPORE-BEARING    BACTERIA. 

A  characteristic  of  the  bacteria  not  to  be  overlooked  in  differentia- 
tion for  species,  is  the  presence  or  absence  of  spores.  This  cannot,  in 
all  cases,  be  easily  determined  ;  but  a  germ  which  yields  spores  is  known 
to  be  much  more  difficult  to  destroy  than  non-spore-bearing  germs. 
The  spores  are  small,  round,  ovoid  or  oblong  bodies,  of  which  one  or 
more  may  be  noticed  in  a  single  bacillus  or  spirillum,  which  will  live 


280 


APPENDIX  B. 


and  propagate  bacteria  of  its  kind  after  the  destruction  of  the  germ 
itself. 

Of  the  pathogenic  bacteria  found  in  water  a  few  develop  spores. 
"  According  to  H  ueppe,  the  Koch  comma  bacillus  forms  arthrospores,  but 
it  possesses  no  form  which  is  endowed  with  any  considerable  powers  of 
resistance.'"  This  view  is  not  shared  by  all  investigators.!  B.  an- 
thracis,  another  pathogenic  germ  found  in  water,  forms  spores.  The 
tetanus  bacillus  forms  a  spore  in  one  end  of  the  rod  which  gives  it  the 
form  of  a  drumstick.  B.  pyocyanus,  found  in  green  pus  and  also  in 
water,  forms  spores.  Bacillus  of  mouse  septicaemia  forms  spores.  Of  the 
twenty-three  pathogenic  species  of  bacteria  found  in  water,  the  above 
are  all  that  are  certainly  known  at  present  to  form  spores. 

The  Franklands  in  their  work  on  Micro  Organisms  in  Water,  give  a 
list  of  200  species  of  the  bacteria  which  have  been  found  in  water,  of 
which  the  following  are  classed  as  pathogenic  varieties  :  — 

PATHOGENIC   BACTERIA    FOUND   IN    VARIOUS   WATERS. 


GERM. 

ORIGINAL  DATE  OF 
IDENTIFICATION. 

AUTHORITY. 

B.  anthracis, 

1850 

Rayer  and  Davaine,  Pollender-Pasteur, 

and  Joubert-Koch. 

B.  typhosus, 

1880 

Eberth-Gaffky. 

B.  mouse  septicamia, 

1881 

Gaffky-Loffier. 

B.  rabbit  septic&mia. 

1881 

Koch-Gaffky. 

B.  pyocyanus, 

1882 

Gessard-Charrin-Ernst. 

Sp.  Asiatic  cholera. 

1884 

Robert  Koch. 

B.  tuberculosis, 

1884 

" 

B.  saprogenes, 

1884 

Rosenbach. 

Staph.  pyogenes  aureus, 

1884 

Rosenbach-Passet-Fick. 

B.  coli  communis, 

1885 

Escherich. 

B.  lactis  aerogenes, 

1885 

" 

B.  proteus  vulgaris, 

1885 

Hauser. 

B.  proteus  tnirabilis, 

1885 

" 

B.  proteus  Zenkeri, 

1885 

" 

B.  brevis, 

1888 

Rintaro  Mori. 

B.  capsulatus, 

1888 

" 

M.  biskra, 

1888 

Heydenrich. 

B.  of  tetanus, 

1889 

Nicolaer-Kitasato. 

Coccus  "  B," 

1890 

Foutin. 

B.  hydrophilus  fuscus,                         1891 

Sanarelli. 

B.  proteus  fluorescent,                         1892 

Jaeger. 

Sp.  Berolin&nsus,                                   1893 

Neisser. 

B.  tholoeideum, 

Gessner. 

*  Micro  Organisms  in  Water,  Percy  &  Grace  Frankland,  London,  1894,  p.  399. 
f  Principles  of  Bacteriology,  by  Dr.  A.  C.  Abbott,  Philadelphia,  1894,  p.  314. 


APPENDIX  B.  281 

In  addition  to  the  pathogenic  bacteria  heretofore  found  in  water, 
certain  investigators  abroad  seem  to  think  that  the  bacillus  of  diphtheria 
may  be  transmitted  through  the  medium  of  water  supply.  In  his  evi- 
dence before  the  Royal  Commission  on  Metropolitan  Water  Supply,  Dr. 
Alfred  Ashby  *  stated  a  belief  that  diphtheria  might  be  so  transmitted. 
Dr.  E.  Frankland  t  says  that  animal  refuse  finding  its  way  into  water 
may  be  accompanied  by  zymotic  poisons  dangerous  to  health,  such  as 
those  of  typhoid  fever,  tuberculosis,  or  diphtheria ;  while  Dr..  George 
Turner  $  testified  before  the  Commission  that,  "  he  had  had  one  case 
where  he  suspected  that  diphtheria  was  conveyed  by  water."  No  proof 
is  at  hand  indicating  the  transmission  of  this  germ  by  water,  although 
it  is  possible  that  it  may  find  its  way  into  water,  in  the  same  way  as 
the  tubercle  bacillus,  by  the  sputa  or  membraneous  sloughings  from  a 
patient  suffering  with  this  disease.  It,  however,  may  be  said  that  the 
remedies  to  be  applied  to  polluted  waters,  or  the  precautions  to  be 
observed  in  selecting  water  from  the  best  natural  sources,  will  have 
the  same  influence  in  diminishing  the  chances  of  propagation  of  diphthe- 
ria (if  it  should  be  shown  to  have  a  temporary  habitat  in  water)  as  upon 
the  transmission  of  typhoid  fever  and  cholera  by  this  means. 

In  order  to  render  the  bacteria  easily  discernible  under  the  micro- 
scope, recourse  is  had  to  dilute  solutions  of  the  aniline  dyes,  which  as 
simple  watery  solutions,  or  in  combination  with  a  weak  acid  or  alkali,  are 
readily  taken  up  by  the  protoplasm  of  the  cell  substance.  The  bacteria 
being  devoid  of  chlorophyl,  and  consequently  colorless  in  drop  cultures 
or  fixed  on  cover  glasses  unstained,  are  somewhat  difficult  to  study; 
while  by  the  addition  of  the  dyes,  or  stains,  these  colorless  bodies  become 
more  or  less  opaque,  and  contrast  sharply  with  the  light  transmitted 
through  the  preparation,  and  when  stained  are  easily  viewed  and  exam- 
ined microscopically. 

The  manner  in  which  the  bacteria  take  the  stain  is  a  material  ele- 
ment in  the  differentiation  of  species,  and  in  jotting  down  the  memo- 
randa of  examination  of  an  organism  the  experienced  observer  never 
fails  to  note  the  facility  with  which  the  stain  is  taken  up.  B.  anthracis 
thus  takes  the  simple  watery  stain  readily,  while  b,  typhosus  can  be 
promptly  colored  only  by  an  acid  or  alkaline  solution  of  the  stains,  and 
the  tubercle  bacillus  stains  with  great  difficulty.  The  bacillus  of  tetanus, 
on  the  other  hand,  is  easily  colored  with  the  watery  solutions,  while 

*  Report  of  Royal  Commission  on  Metropolitan  Water  Supply,  London,  1893,  Minutes 
of  Evidence,  p.  140. 

f  Ibid.,  Appendices  to  Minutes  of  Evidence,  p.  200. 
|  Minutes  of  Evidence,  p.  177. 


282  APPENDIX  B. 

b.  proteus  fluorescens  requires  the  strongest  dyes  to  give  it  color.  This 
property  of  taking  stains  is  affected  by  the  age  of  the  culture,  old  cul- 
tures being  more  troublesome  to  stain  than  young  ones. 

To  illustrate  the  importance  of  familiarity  with  the  action  of  the 
aniline  dyes  on  the  bacteria,  if  a  cover  glass  preparation  suspected  of 
being  the  typhoid  bacillus  was  under  examination,  and  it  took  the  watery 
solutions  promptly,  it  can  be  safely  set  down  that  it  is  not  b.  typhosus, 
but  some  other  germ. 

The  growth  of  the  common  water  bacteria  is  inhibited  by  high  tem- 
peratures, while  the  pathogenic  germs  attain  their  highest  development 
at  the  temperature  of  the  body.  Thus,  while  the  waters  in  rivers,  lakes 
and  reservoirs,  attain  the  highest  temperature  at  the  end  of  summer,  a 
temperature  unfavorable  to  the  growth  of  many  of  the  water  bacteria, 
they  are  approaching  the  condition  favorable  to  the  growth  and  full 
development  of  the  pathogenic  organisms ;  and  it  is  at  this  season  of 
the  year  when  water-borne  diseases  should  be  most  manifest. 

In  the  following  tables  are  given  :  — 

1.  A  list  of  bacteria  found  in  water  which  resemble  the  typhoid 
bacillus  in  some  dimension,  and  like  b.  coli  communis  and  b.  lactis  aero- 
genes,  resemble  it  sometimes  in  other  respects. 

2.  A  list  of  the  germs  smaller  than  b.  typhosus  found  in  water. 

3.  A  list  of  the  larger  bacteria  found  in  water. 

4.  A  list  of  the  spore-bearing  bacteria  which  have  been  found  in 
water. 

In  all  the  tables  the  principal  properties  of  the  organisms  are  given 
to  assist  in  the  rough  identification  or  differentiation  of  species.  But 
for  the  exact  differentiation,  the  best  descriptions  of  the  various  bacteria, 
together  with  long  and  conscientious  experience,  will  be  found  abso- 
lutely necessary.* 

*  In  the  author's  forthcoming  work  on  the  "Interpretation  of  Water  Analysis,"  a  full 
description  will  be  given  of  the  modern  methods  of  Bacterial  Water  Analysis,  and  the  aids  to 
identification  of  species  of  bacteria. 


APPENDIX  B. 


283 


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284 


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APPENDIX  B 


No.  4.     LIST  OF  SPORE-BEARING  GERMS  FOUND  IN  WATER. 


GEBM. 

ACTION 
ON 
GELATIN. 

ENDS. 

COLOK. 

MORPHOLOGY. 

B.  Anthracis, 

Liq., 

Square, 

Gray  white, 

Forms  filaments, 

3-6-10  M  x  1-1.5  M. 

B.  Subtilis, 

" 

Round, 

Opaque  white, 

Long  filaments,  G  ^  x2ju.. 

B.  Vermicularis, 

" 

" 

Gray, 

Forms  extensive  filaments, 

B.  Megaterium, 

M 

« 

Whitish, 

8-9  fji  long,  2.5  M  broad. 

B.  Ramosus, 

" 

" 

Gray, 

Long  filaments,  7  /u  x  1.7/m. 

B.  Mycoides, 

" 

.     . 

White, 

Long  filaments,  1.  6-2.4  p.  x  .9  p.. 

B.  Tetanus, 

" 

Round, 

.    .    . 

.9-1.1  M  x  -1-.2  M. 

B.  Pyocyanus, 

" 

Greenish  white, 

.8-Ux.15-.25M. 

B.  Mouse  septicaemia, 

" 

Yellowish  white, 

Frequently  in  pairs,  .8-1  /u.  ,l-.2fi. 

B.  Brunneus, 

Non-liq., 

.     . 

Milk-white  brown  , 

Fine  and  slender. 

B.  Circulans, 

Liq., 

Round, 

Translucent, 

In  twos  and  fours,  2-5  /u.  x  1  M- 

B.  Erythrosporus, 

Non-liq., 

" 

Fluor-green, 

Slender  and  short  filaments. 

B.  Der  Rothe, 

Liq., 

" 

Raspberry  red, 

Small,  forms  filaments. 

B.  Cuticularis  albus, 

Non-liq., 

" 

White, 

Bent  filaments,  3.2  fi  long. 

B.  Granulosus, 

Liq., 

.     . 

Yellowish  white, 

Long  slender  filaments. 

B.  Limosus, 

" 

Round, 

White, 

Two  or  three  joined,  3-4  /a  xl.25/u.. 

B.  Zopfii, 

" 

.     . 

Whitish  yellow, 

2-5  /ax.  75-1  M. 

B.  Mesentericus  ruber, 

" 

Round, 

Yellow  brown, 

Slender. 

B.  Mesentericus  fuscus, 

" 

.     . 

Brownish  yellow, 

Short,  in  twos  and  fours. 

B.  Mesentericus 

vulgatus, 

11 

Round, 

Yellow, 

Small,  fat,  pairs  and  fours. 

B.  Iridescens, 

" 

.     . 

Greenish  yellow, 

Bent  filaments,  3.5-5.2  /u.  long. 

B.  Guttatus, 

" 

.     . 

Bluish  white, 

1-1.13/u.  x  .93  u. 

B.  Thalassophilus, 

" 

.     . 

Light  gray, 

An  anaerobian,  with  slender,  vari- 

able filaments. 

B.  Amylozyme, 

Non-liq., 

Round, 

White, 

Pairs  and  chains,  2-3  /j.  x  -5  /u.. 

B.  Filiformis, 

Liq., 

White, 

Forms  filaments,  4  n.  x  1  /<*• 

Bacillus  "C," 

Liq., 

.     . 

Pale  brown, 

5-20  nxl/*. 

Bacillus  "D," 

Non-liq., 

Round, 

Pearl, 

l-2/utx.l-.2M. 

B.  Acidi  lactici, 

Non-liq., 

.     . 

Gray  white, 

Pairs  and  fours,  1-1.7  M  x  .3-.4fx. 

B.  Lactis  cyanogenus, 

" 

Blunted 
corners, 

Gray, 

l-4Mx.3-.5M. 

B.  Butyricus, 

Liq., 

Dirty  yellow, 

2.1/HX.38M. 

B.  Crassus  aromaticus, 

Round, 

White 

3.5-5  /u.  x  1.5  /n. 

B.  Aerophilus, 

" 

" 

Greenish  yellow, 

Slender,  in  twos  and  filaments. 

B.  Muscoides, 

Non-liq., 

.     . 

Opalescent, 

IM-  broad. 

B.  Putrificus  coli, 

Liq., 

.     . 

White, 

Slender  filaments,  3/u.  long. 

B.  Thermophilus, 

Non-liq., 

White, 

Forms  filaments. 

APPENDIX    C. 


THE  LEGAL  LIABILITY   OF   CITIES   AND  WATER  COMPANIES 
FOR    DAMAGES   BY    SEWAGE   POLLUTED    WATER. 

EXCEPTING  cities  are  compelled  by  law  to  procure  water  from 
satisfactory  natural  sources,  or  adopt  the  most  perfect  methods  of 
water  purification,  progress  in  the  hygiene  of  public  water  supplies 
will  be  comparatively  slow.  When,  however,  judicial  decrees  are 
obtained  against  vendors  (whether  municipal  corporations  or  pri- 
vate companies)  for  the  distribution  of  polluted  and  unwholesome 
waters,  then  the  interest  of  water  purveyors  in  the  quality  of  their 
commodities  will  be  great  indeed. 

If  cities  and  private  companies  are  held  legally  responsible 
for  all  losses  of  life,  time,  and  money  by  reason  of  polluted  public 
water  supplies,  the  problem  then  will  not  be,  —  is  improvement 
in  water  quality  desirable,  but  rather  how  can  satisfactory  im- 
provement be  obtained.  The  cost  will  not  be  seriously  debated 
then  ;  because  the  possible  loss  of  money  by  damage  suits,  for  a 
brief  period  of  time,  will  more  than  balance  the  cost  of  water  from 
proper  sources,  or  of  the  most  perfect  works  for  the  artificial 
purification  of  polluted  waters. 

Let^  it  be  understood  that  every  gallon  of  water  sent  through 
the  public  mains  must  carry  with  it  the  seal  of  approval  of  con- 
scientious as  well  as  competent  water  analysts,  and  our  public  sup- 
plies will  then  come  from  sources  beyond  the  reach  of  sewage 
pollution,  or  will  be  brought  to  the  highest  state  of  artificial  puri- 
fication which  is  attainable. 

A  successful  suit  has  recently  been  fought  upon  these  lines  in 
the  lower  courts  of  the  State  of  Wisconsin.  There,  in  the  city  of 
Ashland,  an  epidemic  of  typhoid  fever  occurred  during  the  winter 

287 


288  APPENDIX   C. 

of  1893-94  ;  and  notwithstanding  repeated  complaints  by  the  local 
and  state  health  officials,  the  Water  Company  continued  to  supply 
a  sewage  polluted  water  to  its  consumers.  Among  the  victims  of 
this  epidemic  was  one  Lars  G.  Green,  a  laboring  man,  whose  widow, 
Mrs.  Julia  L.  Green,  upon  advice  of  counsel,  began  a  suit  against 
the  Ashland  Water  Company  for  the  legal  value  of  her  husband's 
life. 

The  source  of  water  supply  for  Ashland  was  Chequamegon 
Bay,  an  arm  of  Lake  Superior.  The  same  bay  also  serves  as  the 
receptacle  of  the  city's  sewage  (Chap.  II.)  ;  and  the  water  supplied 
to  the  patrons  of  the  public  mains  was  a  mixture  of  water  as  re- 
ceived from  natural  sources  into  the  bay,  and  the  city's  sewage. 

The  suit  was  based  on  the  theory  that  the  water  from  Che- 
quamegon Bay  contained  the  specific  germs  of  typhoid  fever,  which 
came  into  it  through  the  city  sewers  in  the  dejections  of  typhoid 
fever  patients  then  in  Ashland  ;  that  this  water  was  drunk  by  Mr. 
Green,  and  laid  the  foundation  for  the  disease  by  which  he  per- 
ished ;  and  that  the  Water  Company,  knowing  the  condition  of  the 
water  in  the  bay,  was  negligent  in  supplying  to  their  customers 
water  for  dietetic  uses  which  was  sewage  polluted  and  therefore 
unwholesome. 

The  suit  was  tried  in  the  Circuit  Court  of  Portage  County, 
Wisconsin,  during  the  last  week  of  November  (1897),  before 
Hon.  Chas.  M.  Webb.  Upon  trial  of  the  case,  it  was  proven  that 
Mr.  Green  was  a  railway  employee  living  and  working  continuously 
in  Ashland  ;  that  he  was  taken  ill  with  and  died  of  typhoid  fever  ; 
that  his  premises  were  supplied  with  water  from  the  mains  of 
the  Ashland  Water  Company ;  that  the  only  water  available  in 
Ashland  was  that  supplied  by  the  water  company  from  Chequame- 
gon Bay ;  that  this  water  was  polluted  with  the  sewage  from  the 
city  of  Ashland  ;  that  previous  to  Mr.  Green's  illness  typhoid  fever 
had  prevailed  in  Ashland,  and  the  dejections  from  the  patients  had 
gone  into  the  city  sewers  and  been  discharged  into  Chequamegon 
Bay ;  and  that  with  the  exception  of  four  days  just  prior  to  his  ill- 
ness, Mr.  Green  was  exposed  to  the  influence  of  no  other  water  than 
that  supplied  to  his  premises  and  the  city  of  Ashland. 

From  the  testimony  offered,  the  jury  found  that  the  typhoid 


APPENDIX  C.  ^W^      K*>^  289 


germ  was  transmitted  to  Mr.  Green  through  the  medium  of  the 
public  water  supply,  and  held  the  water  company  liable  in  $5,000 
damages.  (The  legal  value  of  a  human  life  under  the  laws  of 
Wisconsin.) 

Similar  suits  doubtless  will  be  brought  elsewhere,  to  settle 
the  question  of  liability  of  municipal  corporations  and  water  com- 
panies for  delivering  to  their  citizens  or  customers  a  fluid  which 
is  carrying  the  germs  of  dangerous  disease. 


AUTHORITIES    QUOTED    OR    REFERRED   TO. 


ABBOTT,  DR.  A.  C.,  Philadelphia,  "  Principles  of  Bacteriology." 

ALESSI,  DR.  G.,  London,  "  Putrid   Gases   as    Predisposing 

Causes  of  Typhoid  Infection." 

ANDERSON  PURIFIER  Co.,          London,  1896,  "  Water  Purification." 

ANKLAM,  F.,  Berlin,  "  Filters  at  Lake  Miiggel." 

Annales  de  L?  Institute  Pasteur,  Paris,  1892-94. 
Annual  Summary  of  Vital  Sta- 

London,  1890-96. 


BAKER,  M.  N.,  New  York,  "  Mechanical  Filters,"  etc. 

BAUMEISTER,  PROF.  R.,  Carlsrahe,  "CleaningandSeweragecf  Cities." 

BERTSCHINGER,  DR.  A.,  Zurich,  "  Analyses  of  Zurich  Water." 

BINNIE,  SIR  A.  R.,  London,  1894,  "  Available  Sources  of  Water  Sup- 

ply for  London." 
BLESSING,  JAMES  H.,  Albany,  N. Y.,  1897,  "  An   Address   to   the    Common 

Council." 

BRYAN,  W.  B.,  London,  "  Cleaning  Filters."   East  London 

Water*Company. 

CARMICHAEL,  PROF.  H.,  Boston,  1896,  "  Reduction   of  Iron  in   Ground 

Waters." 
Centralblatt  fur  Bacteriologie,     1892,  "  Freudenrich's  Tests  of  Pasteur 

Filters." 
Consular  Reports,  U.S.,  Washington,  D.C.,    "  Fischer  Filter,  Worms." 

1897, 
CROOKSHANK,  E.  M.,  London,  "  Manual  of  Bacteriology." 

DE  VARONA,  I.  M.,  Brooklyn,  1896,         "  Report  on  the  Future  Extension 

of  the  Water  Supply  of  Brook- 
lyn." 

DEVONSHIRE,  E.,  London,  "Anderson  Revolving  Iron  Puri- 

fier." 

DIBDIN,  W.  J.  London,  "  Analytical  Investigation  of  Lon- 

don Waters." 

DROWN,  DR.  T.  M.,  Lehigh  University,    "  Reduction  of   Iron  in  Ground 

South  Bethlehem,      Waters,"  etc. 
Pa., 
DUNBAR,  PROFESSOR  DR.,          Hamburg,  "  Reduction   of   Iron  in  Ground 

Waters,"  etc. 
290 


AUTHORITIES  QUOTED   OR  REFERRED    TO. 


291 


DUPRE,  DR.  A., 


London, 


ENGINEER  Commission  on  Extension  and  Better- 
ment of  Cincinnati  Water  Works,  1896: 
Engineering  News, 

Engineering  Record, 
ERNST,  DR.  H.  C., 


Fire  and  Water, 
FLAD,  EDWARD, 
FRANKLAND,  DR.  E., 

FRANKLAND,  PROF.  PERCY 
and  G.  C., 

GILL,  HENRY,* 


"  Andersfcn  Iron  Purifier,  Worces 
ter,  England." 

"  Report"  on  Filtration  of  Water." 
New  York,  1896,        "  Removal  of  Iron  from  Ground 

Waters,"  etc. 

New  York,  1894,       "  Typhoid  Fever  Statistics." 
Harvard  University,  "  Examination  of  Sample  of  Well 
Boston,  Wa.ter." 

New  York,  1804-95,  "  Typhoid  Fever  Statistics." 
St.  Louis,  "Subsidence  of  Ohio  River  Water." 

London,  "  Operation  of  London   Filters," 

etc. 

Birmingham,  Eng.,    "  Micro  Organisms  in  Water." 


HAWKSLEY,  THOS., 
HAZEN,  ALLEN, 

HOLLIS,  F.  S., 


JORDAN,  DR.  EDWIN  O., 


London, 

London, 
New  York, 

Boston, 

Chicago, 
Karlsruhe,  1897, 


Journal  fur  Gasbeleuchtung 

und  Wasserversorgung, 

Journal  of  the  Sanitary  Institiite,  London,  1894-95. 
Journal  of  the  N.  E.  W.  W.  As- 

1896. 


New  York, 
London, 
Altona,  Ger., 

London, 


KIRKWOOD,  J.  P.,* 
KLEIN,  DR.  E., 

KUMMEL,  W.,* 

LANDOIS-STERLING, 
LANDRETH,  PROF.  O.  H., 


"Filtration  of  the  Muggel  Lake 
Water  Supply." 

"  Area  of  London  Filters." 
"  Filtration  of  Public  Water  Sup- 
plies," etc. 

"  Bacterial    Efficiency    of    Lorain 
Filters." 

"  Identification  of  Typhoid  Fever 

Bacillus." 
"  Cleaning    Sand    Filters    under 

Ice." 

"  Filtration,"  etc. 
"  Influence   of    Light    on    Micro 
Organisms." 

"  Filtration  of  River  Waters." 
"  Quality  of  London  Waters." 
"  Rates  of  Filtration." 

"  Human  Physiology." 


Schenectady,  N.Y.,   "  Epidemic  of  Typhoid  Fever  at 
Elmira,  N.Y." 


LANKESTER,  PROF.  E.  RAY,       Oxford  University,    "Origin  of  b.  typhosus"  etc. 


LEFFMANN,  DR.  HENRY, 
MAGER,  ED., 


Philadelphia,  1897, 


Hamburg,  1897, 


Unfiltered  Surface  Waters  al- 
ways Unsafe  for  Town  Supply." 

Process  of  Cleaning  the  open 
Filters  of  the  Hamburg  Water 
Works." 


Deceased. 


292 


AUTHORITIES  QUOTED   OR  REFERRED    TO. 


Manual  of  American  Water  Works,  New  York,  1897- 


MASON,  PROF.  WILLIAM  P.,  New  York,  1896, 

MASS.  State  Board  of  Health,  Boston,  1890-95, 

MCFARLAND,  DR.  Jos.,  Philadelphia, 

MEYER,  F.  ANDREAS,  Hamburg,  1894, 


MIGULA,  Dr.  WM 
MILLS,  H.  F., 
MIQUEL,  DR.  PIERRE, 
MOORE,  DR.  V.  A. 


London,  1893, 
Lawrence,  Mass., 
Paris, 
Washington,  D.C., 


MORISON-jEWELL  FILTRATION  COMPANY, 


MUNN,  DR.  WILLIAM  P., 

NICHOLS,  WM.  RIPLEY, 

ODLING,  DR.  WILLIAM, 
Ohio  Sanitary  Bulletin, 
OSLER,  DR.  WILLIAM, 


Denver,  Col.,  1896, 


"  Water  Supply." 

Annual  Reports. 

"  The  Pathogenic  Bacteria." 

"  Das  Wasserwerk  der  Frien-  und 

Hansestadt,  Hamburg." 
"  Practical  Bacteriology." 
"  Sterilization  of  Filter  Sand." 
"  Sedimentation  of  Waters,"  etc. 
"  Character  of  the  Flagella." 
"  Experimental  Filters  for  Phila- 
delphia," 1897,  etc. 
"  Preliminary   Report    of    Health 
Commissioner." 


New  York,  1883,       "  Water  Supply.' 


London,  1893, 
Ohio,  1897, 
Baltimore, 


PETTENKOFER,  DR.  MAX  VON,  Munich, 
PIEFKE,  HERR,  Berlin, 

PRELLER,  CHARLES,  S.  D.,         London, 


"  Filtration  of  Surface  Waters." 

"  Lorain  Filters." 

"  Typhoid  Fever  in  Baltimore." 

"  Cause  of  Typhoid  Fever." 

"  Die  Principien  der  Reinwasserge- 
winnung  vermittelst  Filtration." 

"Water  Works  of  Zurich,  Swit- 
zerland." 

"Use  of  Sterilized  Water  at 
World's  Fair."  (1893.) 


Proceedings  American  Water- 
Works  Association,  1894, 

Proceedings  Institution  of  Civil 

Engineers,  London,  1892-1895,  "  Filtration  of  Water  in  Europe." 

PRUDDEN,  DR.  T.  M.,  New  York,  "  Typhoid  Bacillus  in  Water." 


RAFTER  AND  MALLORY, 
RAVENEL,  DR.  M.  P., 
REINCKE,  DR.  J.  J., 

ROGERS,  DR.  EDMUND, 
ROSENAU,  Dr.  M.  J  , 
ROYAL  COMMISSION, 

SANARELLI,  Dr.  G., 

SCHRODER,  RUD, 
SEDGWICK,  PROF.  W.  T., 

SHEDD,  J.  HERBERT* 


Rochester,  N.Y.,        "  Report  on   Spring   Water   Epi- 
demic." 
Philadelphia,  1897,    "  Bacterial     Tests    of    Chemung 

Water,  Elmira,  N.Y. 
Hamburg,  "  Epidemiology  of  Typhoid  Fever 

in  Hamburg  and  Altona." 

Denver,  Col.,  "  Cause  of  Mountain  Fever.  " 

San  Francisco,  "  San  Francisco  Water  Supply." 

London,  1893,  "Metropolitan  Water  Supply." 


Montevideo,  S.A.,  "The  Typhoid  Bacillus  and  Eti- 
ology of  Typhoid  Fever." 

Hamburg,  "  Operation  of  Hamburg  Filters." 

Boston,  "  Bacteria  in  Spring  and  Well 

Waters,"  etc. 

Providence,  R.I.,       "  Sand  Filtration." 


AUTHORITIES  QUOTED   OR  REFERRED    TO. 


293 


SMITH,  DR.  THEOBALD,  Boston, 

Statistische    Zusam menstellung 

der  Betrtebs  Ergebnisse  von 

Wasserwerken,  Munich,  1895. 

STERNBERG,  DR.  GEO.  M.,         Washington,  D.C. 

THOMAS,  R.  J.,  Lowell,  Mass., 

THOMAS  AND  MARSHALL,  DRS.,  Philadelphia, 


THORNE,  DR.  THORNE, 


London, 

New  York,  1894, 


Times,  Daily, 

Transactions  American  Society 

of  Civil  Engineers,  New  York, 

Tribune,  Daily,  New  York,  1894, 


VAUGHAN,  DR.  V.  C., 
VAUGHAN  AND  Now, 


Ann  Arbor,  Mich., 
Philadelphia, 


The  Fermentation  Tube.' 


"  Sources  of  German  Water  Sup 

plies." 
"  Manual  of  Bacteriology." 

"  Water  Supply  of  Lowell." 

Report  on  Philadelphia  Water 
Supply. 

"  The  Caterham  and  Redhill  Epi- 
demic." 

"  Typhoid  Fever." 

Vols.  xxxi.,  xxxii.,  xxxiii.,  and  xxxv. 
"  Typhoid  Fever  and  Water  Sup- 
ply." 

"  A      Bacteriological      Study     of 

Drinking  Water." 
"  The     Ptomaines    and     Leuco- 


WESTON,  EDMUND  B., 
WHIFFLE,  G.  C., 


Providence,  R.I., 
Boston, 


WOODHEAD,  DR.  G.  SIMS,          Edinburgh, 


ZEIMSSEN,  PROFESSOR  VON,       Munich, 
'  itschriftdes  Vereines  Deutsch- 

&  Ingenieurie,  Hamburg,  1895, 

<_    'thrift  fur  Hygiene,  1896, 


"  Providence  Experimental  Filter 
Tests." 

"  Some  Observations  on  the  Re- 
lation of  Light  to  the  Growth 
of  Diatoms." 

"  Seasonal  Distribution  of  Ty- 
phoid Fever,"  etc. 

"  On  Typhoid  Fever  in  Munich." 
"  Apparatus  for   Washing   Filter 

Sand." 
"  Reduction   of  Iron   in   Ground 

Waters." 


INDEX. 


PAGE 

Action  of  b.  typhosus  on  animals  ...  63 
Action  of  bacteria  on  organic  matter  ....  132 
Action  in  water  of  metallic  iron  on  suspended 

matter 241 

Advantage  of  sedimentation 246 

Advantage  of  water  from  undefiled  sources      .    83 

Aeration  of  filter-bed 7,  133,  137,  235 

Aeration  of  polluted  waters 21 

Aeration  of  water  by  Pohle  air  lift  ....  204 
Aeration  of  water  from  Anderson  Purifier  .  .  241 

Aerobic  bacteria 274 

Air-borne  diseases 37 

Altona,  open  filters  of 252 

Alum  and  sand  filtration 173 

Alum   consumption   per  gallon  of  water  with 

mechanical  filters 201 

Alum  per  gallon  of  water,  Lorain,  Ohio  .  .  .  196 
Alum  per  gallon  of  water,  Providence,  R.I.  .  189 

Alum,  reduction  of  bacteria  by 115 

Alum,  test  for,  in  filtrate 189 

Alum,  uudecompossd,  in  subsided  water     .     .  115 
Alum,  use  of,  in  Philadelphia  water  supply     .  201 
Alum,  variable  consumption  of,  with  mechani- 
cal filters 201 

Amsterdam,  filters  of 181 

Anaerobic  bacteria 274 

Analytical  investigation  of  London  water  .  .117 
Analysis  of  Reading,  Mass.,  water  .  .  .  .207 

Analysis  of  sands  and  gravels 162 

Analysis  of  solids  of  putrefactive  bacteria    .     .  272 

Analysis  of  sulphate  of  alumina 189 

Analysis  of  water  at  Long  Branch,  N.J.  .  .  195 
Anderson  Revolving  Iron  Purifier, 

52,  156,  182,  241,  242,  243,  244,  245 

Angers,  France,  filter  gallery 179 

Animal  charcoal  filters  for  reduction  of  iron, 

205,206 
Anklam  and  Oesten's  method  for  reduction  of 

iron  in  ground  waters 205 

Anthrax  protein 273 

Apparatus  required  for  sterilization  of  water   .  123 

Area  of  filters,  Amsterdam 181 

Area  of  filters,  The  Hague 181 

Area  of  filters,  Hamburg 210,  223 

Area  of  filters,  Hudson,  N.Y 177 

Area  of  niters,  Lawrence,  Mass.    .     .     .    166,  169 


PAGE 

Area  of  filters,  London 183 

Area  of  filters,  Lowell,  Mass 176 

Area  of  filters,  Miiggel  Lake 231 

Area  of  filters,  Paris 182 

Area  of  filters,  Poughkeepsie,  N.Y 178 

Area  of  filters,  Rotterdam 180 

Area  of  filters,  Zurich 183 

Area  of  water  on  sand-bed,  Cincinnati  filters  .  249 
Arrangement  of  filtering  materials,  Amsterdam,  181 
Arrangement  of  filtering  materials,  Berlin  .  .  230 
Arrangement  of  filtering  materials,  Cincinnati,  250 
Arrangement  of  filtering  materials,  The  Hague,  181 
Arrangement  of  filtering  materials,  Hamburg,  213 
Arrangement  of  filtering  materials,  Hudson, 

N.Y 177 

Arrangement  of  filtering  materials,  Lawrence, 

Mass 166 

Arrangement   of   filtering   materials,   Lowell, 

Mass 175 

Arrangement  of    filtering   materials,    Miiggel 

Lake 232 

Arrangement  of  filtering  materials,  Paris     .     .  182 
Arrangement    of    filtering    materials,   Pough- 
keepsie, N.Y 178 

Arrangement  of  filtering  materials,  Rotterdam,  180 
Arrangement  of  filtering  materials,  Zurich  .  .  183 
Arrangement  of  main  and  lateral  drains  .  249,  250 

Artesian  well  waters 102,  113 

Arthrospores 280 

Asbury  Park,  N.J.,  mechanical  filters,  203,  263,  264 
Ashland,  Wis.,  sand  filters  .  .  .  261,262,265 
Assimilation  of  minerals  in  water  by  plant  life,  88 

Asterionella 87 

Average  daily  consumption  of  water,  Amster- 
dam   182 

Average  daily  consumption  of  water,  Berlin  .  233 
Average  daily  consumption  of  water,  The 

Hague 181 

Average  daily  consumption   of  water,   Ham- 
burg   220 

Average   daily   consumption   of   water,   Law- 
rence, Mass 169 

Average  daily  consumption  of  water,  Munich,     80 
Average  daily  consumption  of  water,  Rotter- 
dam   180 

Average  daily  consumption  of  water,  Zurich    .  183 


295 


296 


INDEX. 


PAGE 

Average  length  of  run  of  mechanical  filters      .  191 
Average  period  of  operation  of  filters,  Ham- 
burg  220 

Average  rate,  Amsterdam  filters 182 

Average  rate,  Berlin  filters 260 

Average  rate,  The  Hague  niters 181 

Average  rate,  Hamburg  filters 260 

Average  rate,  Lawrence,  Mass.,  filters    .     165,  169 

Average  rate,  London  filters 259 

Average  rate,  Paris  suburbs  filters      ....  182 

Average  rate,  Rotterdam  filters 180 

Average  rate,  Somerville  and  Raritan,  N.J.,  fil- 
ters   194 

Average  rate,  Zurich  filters 260 

Average  size  of  sand-grains 164 

Bacilli,  The 275,  277 

Bacteria,  The 272 

Bacteria  found  in  water  larger  than  b.  typhosus,  285 
Bacteria  found  in  water  resembling  b.  typhosits,  283 
Bacteria  found  in  water  smaller  than  b.  typhosus,  284 

Bacteria  and  organic  matter 273 

Bacteria  from  human  intestine 60 

Bacteria  in  air  and  soil 279 

Bacteria  in  air  of  laboratory 53 

Bacteria  in  artificial  ice 53 

Bacteria  in  Chelsea  water 144 

Bacteria  in  cistern  water 41 

Bacteria  in  distilled  water 52 

Bacteria  in  East  London  water 147 

Bacteria  in  Elbe  water 144,  152 

Bacteria  in  filtered  Elbe  water 152 

Bacteria  in  Grand  Junction  water 146 

Bacteria  in  Lambeth  water 146 

Bacteria  in  New  River  water 147 

Bacteria  in  Ohio  River  water 41 

Bacteria  in  rain-water 50,  51,  279 

Bacteria  in  spring  water 48 

Bacteria  in  Southwark  and  Vauxhall  water  .  145 
Bacteria  in  water  from  stone  disk  and  tube 

filters 47 

Bacteria  in  well  waters  ...  22,  26,  27,  44,  45 
Bacteria  in  West  Middlesex  water  ....  145 
Bacteria,  pathogenic  ...  2,  15,  103,  278,  280 

Bacteria,  putrefactive 2,  278,  279 

Bacteria,  reduction  of,  by  alum .  .  ..  .  112,115 
Bacteria,  reduction  of,  by  lime  .  .  .  112,  114,  117 
Bacteria,  reduction  of,  by  sterilized  clay  .  .114 
Bacteria,  reduction  of,  by  subsidence  .  Ill,  148 
Bacteria,  reduction  of,  by  subsidence  and  filtra- 
tion   148 

Bacterial  action  of  metallic  iron  in  water,  241,  243 
Bacterial  contents  of  Chemung  River  water, 

100,  101,  198,  199 

Bacterial  contents  of  Vanne  water 243 

Bacterial  Contents  of  Various  Waters  .  40 
Bacterial  efficiency,  Anderson  Purifier,  Paris  .  243 
Bacterial  efficiency  of  filters  at  high  rates, 

173,  175,  190,  199,  202 


PAGE 

Bacterial  efficiency  of  filters,  Berlin  ....  237 
Bacterial  efficiency  of  filters,  Hamburg  .  217,  218 
Bacterial  efficiency  of  filters,  Lawrence,  Mass., 

143,  153 
Bacterial  efficiency  of  filters,  Lorain,  Ohio, 

195,  196,  202 

Bacterial  efficiency  of  filters,  Paris      ....  182 
Bacterial  efficiency  of  filters,  Rotterdam      .     .  180 
Bacterial  efficiency  of  Morison  mechanical  fil- 
ter     172,  199 

Bacterial  efficiency  of  sand  filters 143 

B.  aiithracis 273,  276,  280,  281,  285 

B.  colt  comntunis 275,  277,  283 

B,  coli  comtmtnis,  and  b.  lactis  aerogenes,  pro- 
duction of  gas  by 57,  58, 

B.  coli  communis  and  typhoid  fever  ....  63 
B.  coli  communis  in  Chemung  River  water  .  101 

B.  coli  comntunis  in  dejecta        15 

B.  coli  communis  in  impounded  water  .  .  .  103 
B.  coli  communis,  inoculation  of  guinea  pigs 

with 61 

B.  coli  communis  in  polluted  waters  ....     60 
B.  coli  communis  in  water  supply  of  San  Fran- 
cisco       28 

B.  coli  communis  in  well  water  ....      28,  103 

B.  diphtheria 275,  276,  278,  281 

B.  diphtheria,  no  proof  of,  in  water  ....  281 

B.  fluorescent  liquefaciens 277,  283 

B,  lactis  aerogenes   .     57,  58,  60,  277,  280,  282,  283 

B.  mesentericus  -vulgatus 279,  286 

B,  of  mouse  septiccemia 280,  284 

B.  prodigiosus 277,  285 

B.  proteus  fluorescens 278,  280,  282 

B.  proteus  vulgaris  ....  28,  103,  279,  280 
B.  protetis  vulgaris  in  water  supply  of  San 

Francisco 28 

B.  pyocyanus 280,  284 

B.  rothe 277,  286 

B.  tetanus 274,280,281,284,286 

B.  tuberculosis 273,  275,  280,  281 

B.  typhosns  .  9,  11,  13,  15,  17,  30,  49,  56,  57,  58,  59, 
60,  61,  62,  G3,  64,  65,  275,  276,  277,  278,  280, 
281,  282,    283 
B.  typhosus,  b.   coli  communis,  and  b.  lactis 

aerogenes 57,58,59,60 

B.  typhosus,  chemical  composition  of .  .  .  56,  57 
B.  typhosus,  form  and  dimensions  of  .  .  57,  278 

B.  typhosus  in  acid  solution 58 

B.  typhosus  in  fermentation  tube 57 

B.  typhosus,  influence  of,  on  gelatin,  56,  57,  58,  283 
B.  typhosus  in  sterilized  milk  .  .  .  .  56,  58,  59 

B.  venenosus 99 

B.  violaceus 278 

Beer,  consumption  of,  in  European  cities, 

13,  78,  79,  80,  139 

Berlin  and  Chicago,  water  consumption   com- 
pared     8 

Berlin,  Plain  Sand  Filters  of 230 

Berlin,  sources  of  water  supply 75 


INDEX. 


297 


PAGE 

Biologic  action  of  sand  filters     .    132,  133,  154,  165 
Boiled  water    ............  121 

Brieger,  reduction  of  toxins  in  bacterial  cul- 
tures    ............     3,  62 

Brooklyn,  ground  water  supply      .....     82 

Capacity  of  Anderson  Purifiers,  Paris  .     .  243 
Capacity  of  clear-well,  Cincinnati  niters  .    250,  251 
Capacity  of  filters,  Mtiggel  Lake    .     .     .    231,  234 
Capacity  of  Fischer  filter,  Worms  .....  240 

Capacity  of  Lawrence,  Mass.,  City  filter      .     .  168 
Capacity  of  London  filters      .......  183 

Capacity  of  mechanical  filters,  Somerville  and 
Raritan,  N.J  ...........  194 

Capacity  of  proposed  filters,  Cincinnati  .     .     .  247 
Capacity  of  proposed  settling-basins,  Cincin- 
nati ..............  247 

Capacity  of  Schroder  sand  washer  .....  223 

.  208 
.     93 
.     25 
2,  85 
135 
56 


Capacity  of  settling-basins,  Hamburg      .     . 
Caterham  and  Redhill,  epidemic  of  typhoid 
Causes  of  failure  in  filtration  of  water     .. 
Changes  in  the  quality  of  a  water  supply     . 
Changes  'of  pressure  on  sand-bed 
Characteristics  of  b,  typhosus 
Chelsea  filters,  London      ......      25,  144 

Chemical  analysis  of  Lake  Superior  water  .     .    99 
Chemical  and  bacterial    efficiency  of  Fischer 

filter      .............  240 

Chemical  and  biological  changes  by  sedimenta- 

tion ..............  110 

Chemical  composition  of  b.  typhostts  ....     56 

Chemical  composition  of  the  bacteria      .     .     .  272 
Chemical  constituents  of  rain-water    ....    51 

Chemically  and  bacterially  pure  water    ...      3 
Chemicals  used  in  Morison  experimental  filter, 

187,  188 
Chemung  River  as  a  carrier  of  typhoid  infec- 

tion ..............  100 

Chicago  and  Berlin,  water  consumption  com- 

pared   .............     82 

Chlorophyl  .............  272 

Cholera  bacillus   ........  23,276,280 

Chromogenic  bacteria   .........  277 

Cincinnati  and  Hamburg,  water  consumption 

compared  ............     82 

Cincinnati  as  a  typhoid  fever  center    ....    42 

Cincinnati,  filters  proposed  for  ......  246 

Cisterns,  precautions  with  underground  ...     86 
Cistern  water  for  dietetic  purposes      ....     86 

Citations  on  Typhoid  Fever  Epidemics    .    91 
Cities  of  second  class  in  United  States    ...    75 
Clarified  and  purified  water   .......    46 

Classification     of     Cities     by     Typhoid 

Fever  Rates  ....     70,  71,  72,  73,  74,  75 

Clay  sterilized,  reduction  of  bacteria  by  ...  114 
Cleaning  the  sand  of  mechanical  filters    .     .     .  184 
Clear-water  conduit  and  basin,  Hamburg    .     .  219 
Clear-water  reservoir,  Berlin      ......  233 

Coagulants,  use  of,  with  mechanical  filters  .     .  184 


PAGE 

Cocci,  The 275 

Collection  of  water  in  impounding  reservoirs  .     14 
Colne  Valley  water,  treatment  of  with  lime      .  113 

Comma  Bacillus,  Koch's 276,  280 

Comparison  of  cities  upon  typhoid  fever  rates, 

Europe  and  United  States  ......    75 

Comparison  of    continuous   and   intermittent 

sand  filters 143 

Comparison  of  large  and  small  cities  for  water 

supply 88 

Comparison  of  natural  and  artificial  sand  fil- 
tration   138 

Comparison  of  population  and  water  consump- 
tion   87 

Comparison   of    typhoid  fever  rates,    Berlin, 
Chicago,   Louisville,   Munich,    Pittsburg, 

Vienna 12 

Comparison   of  water  supplies,    Europe  and 

United  States 77 

Constituents  of  sewage 10 

Construction  of  filters,  Hamburg 210 

Construction  of  mechanical  filters 185 

Construction  of  plain  sand  filters 160 

Consumption  and  waste  of  water  in  American 

cities 82 

Consumption  of  alum  with  mechanical  filters  .  201 
Consumption  of  beer  in  American  and  foreign 

cities 13 

Consumption  of  beer  in  Munich 80 

Consumption  of  water,  Amsterdam     ....  182 

Consumption  of  water,  Berlin 234 

Consumption  of  water,  German  cities      ...    84 
Consumption  of  water,  The  Hague     ....  181 

Consumption  of  water,  Hamburg 220 

Consumption  of  water,  Jersey  City,  N.J.    .     .    34 
Consumption  of  water,  Lawrence,  Mass.     .     .  169 

Consumption  of  water,  London 118 

Consumption  of  water,  Munich 80 

Consumption  of  water,  Rotterdam 180 

Consumption  of  water,  Zurich 183 

Continuous  sand  filtration 158 

Continuous  use  of  sand  filters,  London    .     .     .  261 
Cost  of  Anderson  Revolving  Iron  Purifier,  243,  244 

Cost  of  Ashland,  Wis.,  filters 259 

Cost  of  cleaning  Lowell,  Mass.,  filter      .     .     .  176 

Cost  of  covered  filters,  Berlin 258 

Cost  of  covered  filters,  Zurich 258 

Cost  of  Filters  and  Filtration 255 

Cost  of  filters,  Berlin  and  Hamburg   .     .    253,  254 

Cost  of  filters,  Long  Branch 195 

Cost  of  filters,  Somerville  and  Raritan,  N.J.   .  194 

Cost  of  filtration  for  Albany,  N.Y 196 

Cost  of  filtration,  Miiggel  Lake 233 

Cost  of  filtration,  Poughkeepsie,  N.Y.    .     .     .178 

Cost  of  Fischer  filter,  Worms 240 

Cost  of  Kronke  method  for  reduction  of  iron 

in  ground  waters 205 

Cost  of  lime  treatment  per  million  U.  S.  gal- 
lons .  .  119 


298 


INDEX. 


Cost  of  mechanical  and  plain  sand  niters,  192,  193 
Cost  of  operating  Lawrence,  Mass.,  City  filter,  168 
Cost  of  operating  mechanical  filters  .  .  193,  197 
Cost  of  operating  open  and  closed  filters,  Zurich, 

233,264 

Cost  of  operating  plain  sand  filters  .  .  197,  263 
Cost  of  plain  sand  filters, 

240,  245,  255,  256,  257,  258 

Cost  of  Schroder  sand  washer 223 

Cost  of  scraping  sand-bed,  London  filters, 

176,  262,  263 
Cost  of  sterilizing  large  quantities  of  water, 

121,  124,  125 
Cost  of  treating  water  by  Anderson  process, 

244,245 

Cost  of  uncovered  filters,   Berlin  and   Ham- 
burg       258 

Cost  of  uncovered  filters,  Lawrence,  Mass. .     .  258 

Cost  of  uncovered  filters,  Zurich 258 

Cost  of  washing  sand 263 

Cost  of  washing  sand,  Hamburg 264 

Cost  of  washing  sand,  Lawrence,  Mass.  .  .  263 
Cost  of  water  sterilizing  apparatus  .  .  124,  125 

Covered  filters 158,232 

Covered  reservoirs  forstorage  of  ground  waters,  87 
Covered  reservoirs  for  filtered  water  .  .  156,  157 
Crenothrix 87 

Dayton,  Ohio,  Ground  Water  Supply  ...  82 
Decline  of  typhoid  fever  in  Vienna  and  Munich,  67 
Decomposition  of  organic  matter  in  water  .  .  7 
Degree  of  purity  of  natural  waters  ....  81 

Dejecta  from  typhoid  patients 63,  91 

Delivery  of  water  on  sand-bed 250 

Denver,  Col.,  typhoid  fever  rates  .     .     .     105,  106 

Deposit  on  sand-bed.     (Berlin.) 235 

Digestion,  effect  of  astringent  on 200 

Dilution  of  sewage-polluted  water 3 

Dimensions  of  filters,  Cincinnati 247 

Dimensions  of  filters,  Lawrence,  Mass.  .     .     .  166 

Dimensions  of  typhoid  bacillus 278 

Diplococci,  The 275 

Diphtheria,  no  proof  of  infection  by  water  .     .  281 

Diseases  from  soil  and  water 37 

Distillation  of  public  water  supplies  .  .  .  121 
Distilled  water,  influence  of,  on  health  ...  85 

Distilled  water,  organic  matter  in 17 

Distributing  reservoirs  for  filtered  water  .  .  156 
Distrust  of  natural  sources  of  water  supply  .  29 

Domestic  filters,  use  of 120,  131 

Domestic  filters,  use  of,  with  Ohio  River  water, 

»  42,  43,  47 

Domestic  use  of  polluted  waters 4 

Dortmund,  Ground  Water  Supply      ....    83 

Double  filtration  of  water 154 

Dual  system  of  water  supply  ....  83,  129 
Duplicate  system  of  street  mains  .  121,  124,  125 

Eberth's  bacillus 62,  64 


PAGE 

Effective  sedimentation  of  polluted  waters  .  .110 
Effective  size  of  sand  grains  ....  143,  164,  172 

Effect  of  astringent  on  digestion 200 

Efficiency  of  Anderson  Purifier  on  Ohio  River 

water 52,  244 

Efficiency  of  filters  at  high  rates  of  percolation,  2CO 

Efficiency  of  filters,  Hamburg 153 

Efficiency  of  filters,  Lawrence,  Mass.      .     .     .  153 

Efficiency  of  filters,  London 148,  151 

Efficiency  of  filters,  measurement  of  ....  155 

Efficiency  of  filters,  Reading,  Mass 207 

Efficiency  of  filters,  Rotterdam 180 

Efficiency  of  filters,  Somerville  and  Raritan, 

NJ 194 

Efficiency  of  Kronke  method  for  iron  reduction,  205 

Effluent  regulating  weir 214 

Elizabeth,  N.J.,  epidemic  of  typhoid  .  .  .  108 
Elmira,  N.Y.,  epidemic  of  typhoid  ....  100 

Elmira,  N.Y.,  Filtration  Works 198 

English  Engineers,  views  of,   on  sedimenta- 
tion        141 

Environment,  influence  of,  on  species  ...  64 
Epidemic  of  typhoid,  Caterham  and  Redhill  .  93 
Epidemic  of  typhoid,  Elizabeth,  N.J.  .  .  .108 

Epidemic  of  typhoid,  Elmira,  N.Y 100 

Epidemic  of  typhoid,  Evansville,  Ind.    .     .     .  108 

Epidemic  of  typhoid,  Lausen 91 

Epidemic  of  typhoid,  Lawrence,  Mass.  ...  98 
Epidemic  of  typhoid,  Lowell,  Mass.  ...  98 
Epidemic  of  typhoid,  Middletown,  Conn.  .  .  106 
Epidemic  of  typhoid,  Plymouth,  Pa.  ...  94 
Epidemic  of  typhoid,  Sault  Ste.  Marie,  Mich.  99 
Epidemic  of  typhoid,  Spring  Water,  N.Y.  .  .  96 
Epidemic  of  typhoid,  Stamford,  Conn.  .  .  .  107 
Epidemic  of  typhoid,  St.  Louis,  Mo.  ...  99 

Epidemic  of  typhoid,  Zurich 96 

Estimated  cost  of  a  system  of  filters  ....  256 

Estimated  cost  of  covered  filters 256 

Estimated  cost  of  filters,  Albany,  N.Y.  .  .  .  257 
Estimated  cost  of  filters,  Cincinnati  .  .  252,  253 
Estimated  cost  of  filters,  Philadelphia,  Pa.  .  .255 
Estimated  cost  of  filters,  Providence,  R.I.  .  .256 

Estimated  cost  of  open  filters 256 

Evansville,  Ind.,  epidemic  of  typhoid  .  .  .  108 
Exclusion  of  b.  typhosus  from  drinking-water  .  65 
Experimental  filters,  Providence,  R.I.  .  .  .  170 
Experiments  on  b,  typhosus  and  b.  colicommunis 

in  sterilized  milk 59 

Experiments  with  sterilized  sand,  Berlin,    236,  237 
Evidence  of  b-  typhosus  in  water  supply       .     .     57 
Evidence  that  typhoid  fever  rates  can  be  con- 
trolled   75 

Factors  of  sand  filtration 8 

Facultative  parasites 273 

Facultative  saprophytes 273 

Feasibility  of  water  supply  from  sources  nat- 
urally pure 90 

Fermentation  tube,  the 57,  103 


INDEX. 


299 


PAGE 

Ferrous  hydrate,  formation  of,  by  Anderson 

process 241,  243 

Filaments  of  bacteria 276 

Filter  capacity  in  reserve 210,  231 

Filter  galleries 179 

Filter  gallery,  Angers,  France 179 

Filter  galleries,  Lyons,  France 179 

Filter  gallery,  Perth,  Scotland 179 

Filter  galleries,  rate  of  percolation     ....  179 

Filter  gallery,  Toulouse,  France 179 

Filter  galleries,  quality  of  water  from      .     .     .  179 

Filters  of  Hamburg 77,  208 

Filters  of  the  cities  of  Holland 5 

Filters,  management  of 83 

Filters,  management  of,  at  Berlin 234 

Filters  Proposed  for  Cincinnati    .     .     .     .246 

Filters  of  Zurich 183 

Filters,  rate  of  delivery 161 

Filtered  water,  use  of,  for  washing  sand      .     .  214 

Filtering  materials 162 

Filtration  of  surface  waters 84 

Filtration  of  lake  waters    .../.....    20 

Filtration  of  the  Vyrnwy  water 81 

Filtration  of  Water  Supplies 131 

Filtration  of  water   from  Welsh   sources  for 

London 84,  141 

Filtration  through  the  drift    .     .  26,  27,  28,  139, 179 

Filtration  with  and  without  alum 173 

Filtration  Works,  Elmira,  N.Y 198 

Filtration  Works,  Miiggel  Lake     .     .     .    230,  231 

Fischer  Filter,  Worms 238 

Flagella,  The, 277 

Food  for  bacteria  in  water 134 

Form  and  dimensions  of  b.  typhosus  .  .  57,  278 
Formation  of  nitrates  and  nitrites,  133,  136, 137, 194 
Free  sulphuric  acid  in  water  treated  with 

alum 200 

Freudenrich's  tests  of  Pasteur  niters  .     .     .   43, 45 

Gas,  production  of,  by  b.  colt  communis  and  b. 

lactis  aerogenes 58 

Gelatinous  film  on  sand-bed 133 

General  use  of  unpotable  water 120 

Germ  theory  of  disease 10 

Grada  of  sand  in  London  filters  ..;...  184 

Grading  of  filtering  materials 162 

Grouping  of  species 275,  276 

Ground  water  sources  in  Germany  .  .  .  83,  84 
Ground  water  supply,  Brooklyn,  N.Y.  ...  82 
Ground  water  supply,  cities  of  Germany  .  .  84 
Ground  water  supply,  Dayton,  Ohio  ....  82 

Ground  water  supply,  Dortmund 83 

Ground  water  supply,  Jacksonville,  Fla.  .  .  82 
Ground  water  supply,  Kent  Works,  London  .  83 

Ground  water  supply,  Leipsic 83 

Ground  water  supply,  Lowell,  Mass.  ...  82 
Ground  water  supply,  Memphis,  Tenn. ...  82 
Ground  water  supply,  South  Bend,  Ind.  .  .  82 
Growth  of  bacilli  by  fission 275,  276 


Growth  of  bacteria  in  sand-bed 


PAGE 
.  134 


Habitat  of  b.  typhosus 64 

Hague,  The,  filters  of 181 

Hamburg  and  Cincinnati,  water  consumption 

compared .     82 

Hamburg  Settling-Basins  and  Filters     .  208 

Hamburg,  water  supply  of 77,  208 

Hard  and  soft  pure  water 31 

Hardness  of  Ohio  River  water 28 

Head  of  water  on  Berlin  filters 232 

Head  of  water  on  Fischer  filter 238 

Head  of  water  on  Hamburg  filters  ....  213 
Head  of  water  used  on  sand  washers  .  .  .  223 

High  rates  of  filtration 25,  26,  259,  260 

Holland,  filters  of 5 

Hollow  porous  glass  plaques  for  filtration  .     .  238 

Hudson,  N.Y.,  sand  filters 177 

Hygienic  Laboratory,  Hamburg 5 

Ice,  formation  of,  on  filters 158 

Identification  of  the  typhoid  bacillus  .  .  64,  288 
Imperial  Board  of  Health  (Germany)  on  rate 

of  filtration 142 

Impounding  reservoirs  at  high  elevations    .     .     15 
Impounding  reservoirs  of  New  York  and  Liver- 
pool       21 

Infection  of  milk,  by  typhoid  tainted  water, 

107,  108 

Infectious  disease,  sources  of 37 

Influence  of  alkalinity  on  bacteria  in  water  .  23 
Influence  of  b.  typhosus  on  gelatin  .  .  .56,  58 
Influence  of  casing-pipe  on  bacteria  in  well 

waters 27 

Influence  of  climate  on  filter  construction  .  .  251 
Influence  of  culture  media  on  species  .  .  .  277 
Influence  of  days  of  cultivation  on  bacteria  .  48 
Influence  of  distilled  water  on  bone  formation,  86 
Influence  of  distilled  water  on  health  ...  85 
Influence  of  environment  on  species  .  .  64,  277 
Influence  of  filtered  water  on  bacteria  in  water 

mains 153 

Influence  on  filtration  of  effective  size  of  sand 

grains 173 

Influence  of  form  of  filter 158 

Influence  of  freezing  weather  on  open  filters  .  149 
Influence  of  hard  water  on  the  animal  system  .  30 
Influence  of  London  water  on  typhoid  fever 

rates 11 

Influence  of  management  on  filtration,  83,  253,  254 
Influence  of  nitrates  and  nitrites  on  bacteria  .  23 

Influence  of  origin  on  culture 277 

Influence  of  putrid  gases  on  rats,  guinea  pigs, 

and  rabbits 61 

Influence  of  sand  filtration  on  typhoid  fever 

rates 131,  155 

Influence  of  sewerage  on  typhoid  rates  ...  68 
Influence  of  sterilized  water  on  typhoid  rates  .  128 
Influence  of  sunlight  on  growth  of  algae  .  .  87 


300 


INDEX. 


PAGE 

Influence  of  sunlight  on  growth  of  bacteria  in 

water 53,54,55 

Influence  of  sunlight  on  turbid  waters  ...  87 
Influence  of  temperature  on  growth  of  species,  277 
Influence  of  temperature  on  growth  of  bacteria 

in  water 282 

Influence  of  time  on  efficiency  of  charcoal 

filters 206 

Influence  of  variable  rates  of  filtration  .  .  .  215 
Influent  and  effluent  regulators  .  .  .  209,  214,  247 
Inoculation  of  guinea  pigs  with  b.  coli  com- 

munis 61 

Intermittent  sand  filters 203 

Iron  in  ground  waters,  reduction  of  ....  203 

Jacksonville,  Fla.,  ground  water  supply  .  .  82 
Jersey  City,  N.J.,  consumption  of  water  .  .  34 
Jersey  City,  N.J.,  reduction  of  typhoid  fever,  35 
Jersey  City,  N. J.,  typhoid  fever  rates,  32, 33, 34,  35 
Jersey  City,  N.J.,  water  supply  of  ....  32 

Jewell  mechanical  filters 186,  195 

Judicial  decisions  on  quality  of  water  supply,  109,287 

Kent  Works,  London,  ground  water  supply,    83 

Keyport,  N.J.,  mechanical  filters 264 

Koch's  Comma  Bacilliis 276,  280 

'Kronke  method  of  iron  reduction 205 

Lake  Miiggel  water 140 

Lake  water,  filtration  of 20 

Lake  Zurich  as  a  source  of  water  supply      .     .    20 

Lausen,  typhoid  fever  epidemic 91 

Lawrence,  Mass.,  city  filter 166 

Lawrence,  Mass.,  epidemic  of  typhoid    ...    98 
Lawrence,  Mass.,  reduction  of  typhoid  fever  in,    36 
Lawrence,  Mass  ,  storage  reservoir    ....  156 
Lawrence,  Mass.,watersupplyandtyphoidrates,   36 
Legal  Liability  of  Cities  and  Water  Com- 
panies for  Damages  by  Sewage-Pol- 
luted Water 287 

Leipsic,  ground  water  supply 83,  84 

Lime,  reduction  of  albuminoid  ammonia  by  .  118 
Lime,  reduction  of  bacteria  by  .  .  112,  114,  117 

Lime,  reduction  of  hardness  by 117 

Lime,  reduction  of  total  solids  by 118 

Lime  treatment  of  London  water 118 

Lime  treatment,  cost  per  million  U.  S.  gallons,  119 
Limiting  the  head  on  filters,  Berlin  .  .  136,  234 

Limpidity  and  purity  of  water 12 

Liquefying  bacteria 274 

Local  causes  of  typhoid  fever 39 

Location  of  cities,  ruling  factor 90 

London,  a  city  of  the  second  class 76 

London  and  Philadelphia,  water  consumption 

compared 82 

London,  treatment  of  water  by  lime  .  .  118,  119 
Long  Branch,  N.J.,  mechanical  filter  .  .  .  195 
Longevity  of  the  typhoid  bacillus  in  water  .  17,  42 
Lorain,  Ohio,  mechanical  filters 195 


PAGE 

Loss  by  typhoid  fever  in  large  cities  of  Europe 

and  Australia 270, 271 

Loss  by  typhoid  fever  in  large  cities  of  United 

States  and  Canada 109,  268, 269 

Loss  of  salts  and  minerals  in  water  by  distilla- 
tion   85 

Lowell,  Mass.,  epidemic  of  typhoid    ....     98 

Lowell,  Mass.,  filter-bed 175 

Lowell,  Mass.,  ground  water  supply  .  .  .37,  82 
Lowell,  Mass.,  reduction  of  typhoid  fever  .  .  36 
Lowell,  Mass.,  water  supply  and  typhoid  rates,  36 
Lyons,  France,  filter  gallery 179 

Mager  sand-scraping  apparatus  ....  224 

Management  of  filters 83 

Management  of  filters,  Berlin  ....  234,  235 
Manchester,  Eng.,  water  supply  of  ....  5 
Malvoz'  experiments  with  b.  coli  communis  .  64 
Marston  Lake  as  a  source  of  water  supply  .  .  106 

Af.  Aurantiacus 278 

Maximum  rate  of  filtration,  London  ....  259 
Maximum  yield  of  filters,  Hamburg  ....  2lIO 

M.  Candicans 278 

M.  Carneus 278 

Measurement  of  efficiency  of  filters     ....  155 

Measurement  of  the  bacteria 278 

Mechanical  filters  in  American  cities  ....  193 

Mechanical  filters,  Lorain,  Ohio 266 

Mechanical  niters,  Philadelphia,  Pa 197 

Mechanical  Filters,  Rate  of  Filtration  .  184 
Mechanical  filters,  Somerville  and  Raritan,N.J.  194 

Mechanical  sand  filters 158,  184 

Memphis,  Tenn.,  ground  water  supply    ...    82 
Merrimac  River  as  a  carrier  of  typhoid  infec- 
tion   98 

Method  of  bacterial  examination,  Miquel  .  .  243 
Method  of  operating  Morison  filter  ....  186 

Micrococci,  The -  .     .  275 

Middletown,  Conn.,  epidemic  of  typhoid  fever,  106 
Milk  as  a  carrier  of  typhoid  infection  .  .  .  107 
Milk,  infection  of,  by  typhoid-tainted  water  .  108 
Minimum  rate  of  filtration,  London  ....  259 
Minute  amount  of  organic  matter  in  distilled 

water 17 

Morison  mechanical  filter 172,  184 

Morison  mechanical  filter,  bacterial  efficiency 

of 172 

Motility  of  the  bacteria 276,  277 

Motility  of  b.  typhosus 276 

Mountain  sources  of  water  supply       .     .  37,  81,  90 

Munich,  consumption  of  beer  in 80 

Munich,  consumption  of  water  in  .....  80 
Munich,  decline  of  typhoid  fever  in  ....  67 

Munich,  source  of  water  supply 16 

Mycoprotein 272 

Natural  and  alum  nitration,  relative  effi- 
ciency of   173,198 

Natural  filtration  through  the  drift      .     .    138,  139 


INDEX. 


301 


PAGE 

Natural  purification  of  water  in  the  drift      .     .    22 

Natural  sand  nitration 139,  158 

Natural  sources  of  pure  water  not  generally 

available 81 

Nencki  on  chemical  composition  of  the  bac- 
teria       272 

Nitrates  and  nitrites 273 

Nitrifying  bacteria 273 

Nitrifying  bacteria  in  sand-beds  of  filters,    133,  136 

Non-liquefying  bacteria 274 

Nostoc .87 


.  10 
.  210 
.  31 
.  87 
.  112 


Object  of  water  purification      .     . 

Objections  to  filters  of  large  area    . 

Objections  to  sewage-polluted  water  . 

Odors  and  tastes  in  stored  waters  .     . 

Ohio  River  water,  lime  treatment  of  . 

Ohio  River  water,  sedimentation  of    .     .     .     .111 

Ohio  River  water,  test  of,  in  Parietti  solution  .    50 

Open  filters 158,  210 

Open  filters,  Altona 252 

Open  or  closed  filters  for  Cincinnati  ....  251 
Operation  of  London  filters,  144,  145,  146,  147,  148 

Organic  matter  on  watersheds 14 

Oscillaria, 87 

Oysters  as  a  cause  of  typhoid  infection   .     .     .  106 

Parasitic  bacteria 273 

Parietti  solution,  test  of  Ohio  River  water  with, 

49,50 

Paring  of  sand-bed 133 

Paris,  France,  Anderson  Purifiers 182 

Paris,  France,  Storage  Reservoirs  ....  156 
Pathogenic  bacteria  .  .  .  2,  15,  103,  277,  278,  280 
Pathogenic  bacteria  in  plate  cultures  .  .  .  .277 

Pathogenic  organisms  in  water 29,  280 

Pedesis 277 

Percentage  of  typhoid  mortality 66 

Percentage  of  filtered  water  available  for  con- 
sumption   263,  264 

Percentage  of  filtered  water  required  for  wash- 
ing sand 263,  264 

Period  of  operation  of  filters  .  .  .  161,  228,  261 
Period  of  operation  of  filters,  Berlin  .  .  261,  262 
Period  of  operation  of  filters,  Hamburg, 

216,  217,  220,  261 

Period  of  operation  of  filter,  Lawrence,  Mass.,  262 
Period  of  operation  of  filters,  London  .  .  .  262 
Period  of  operation  of  filters,  Lowell,  Mass.  .  176 
Period  of  operation  of  filters,  Providence,  R.I., 

171,  172,  262 
Period  of  operation  of  filters,  Zurich  .     .     .     .261 

Perth,  Scotland,  filter  gallery 179 

Petroleum  in  drinking-waters 86 

Pettenkofer's  theory  of  typhoid  fever  .  .  66,  69 
Pequannock  River  as  a  source  of  water  supply,  33 
Philadelphia  and  London,  water  consumption 

compared 82 

Piefke  method  for  reduction  of  iron  in  ground 
waters  .  .  205 


PAGE 

Plymouth,  Pa.,  epidemic  of  typhoid  fever  .    .    94 

Poisonous  minerals  in  water 86 

Pollution  of  lakes 20 

Pollution  of  shallow  wells 22 

Pollution  of  water  by  fertilizers 23 

Population   of   the   large  cities  of  Australia, 

Europe,  and  United  States,  268,  269,  270,  271 
Potash  alum,  treatment  of  water  by  .  .  .  .112 
Poughkeepsie,  settling-basins  and  filters  .  .  178 
Precautions  with  underground  cisterns  ...  86 
Production  of  gas  by  b.  coli  communis  and 

b.  lac t is  aerogenes 57 

Products  of  bacterial  action 273 

Propagation    of   typhoid    fever   by   drinking- 
water    65 

Proportion  of  water  for  domestic  uses  ...  78 
Proposed  rate  of  filtration,  Denver,  Col.  .  .  260 

Protection  of  River  Thames 17 

Protection  of  watersheds 21,  76,  81 

Providence  experimental  filter  tests    ....  170 

Ptomains,  The 3,  4,  278 

Ptomains  in  water 4,  278 

Public  improvements  and  politics  .     .     .     126,  254 

Pure  and  impure  water 2 

Pure  and  Purified  Water 81 

Pure  water  not  found  in  nature 3 

Putrefactive  bacteria 2,  103 

Putrid  gases  as  predisposing  causes  of  typhoid 
fever 61 

Quality  of  water  from  filter  galleries  .  .  .  179 
Quincy,  111.,  storage  reservoir 157 

Rainfall  and  Typhoid  Fever 104 

Rare  occurrence  of  sources  of  water  supply  at 

high  elevation 16,  90 

Raritan  and  Somerville,  N.J.,  mechanical  fil- 
ters of 194 

Rate  of  delivery  of  filters 161 

Rates  of  filtration     .     .    26,  161,  165,  168,  259,  260 

Rate  of  filtration,  Amsterdam 182 

Rate  of  filtration,  Ashland,  Wis 260 

Rate  of  filtration,  Berlin 232 

Rate  of  filtration,  Cincinnati,  proposed  for,  247,  249 
Rates  of  filtration,  Fischer  filter,  Worms  .  .  240 
Rate  of  filtration,  The  Hague  ......  181 

Rate  of  filtration,  Hamburg 217 

Rate  of  filtration,  Hudson,  N.Y 178 

Rate  of  filtration,  Lawrence,  Mass.     .     .     143,  169 

Rate  of  filtration,  London 183 

Rate  of  filtration,  Lowell,  Mass 176 

Rate  of.filtration,  mechanical  filters  ....  184 
Rate  of  filtration,  M orison  filter  .  .  .  188,  190 

Rate  of  filtration,  Paris 182 

Rate  of  filtration,  Poughkeepsie,  N.Y.    .     .     .178 

Rate  of  filtration,  Providence,  R.I 171 

Rate  of  filtration,  Rotterdam 180 

Rate  of  filtration,  Tacoma 260 

Rate  of  filtration,  Zurich 143,  183 


302 


INDEX. 


PAGE 

Rate  of  growth  of  bacteria 276 

Rate  of  liquefaction  of  gelatin 172 

Rate  of  percolation  into  filter  galleries  .  .  .179 
Rate  of  percolation  through  the  drift  ....  26 
Reading,  Mass.,  mechanical  filters  ....  207 
Recovery  of  heat  from  distilled  water  .  .  .  122 
Reduction  of  albuminoid  ammonia  by  lime 

treatment  of  water 118 

Reduction  of  bacteria  by  alum  treatment  of 

water 112,  115 

Reduction  of  bacteria  by  filtration  ....  165 
Reduction  of  bacteria  by  Lawrence  filter,  153,  169 
Reduction  of  bacteria  by  lime  treatment  of 

water 112,  113,  114,  117 

Reduction  of  bacteria  by  sedimentation  .  Ill,  112 
Reduction  of  bacteria  by  sterilized  clay  .  .  .113 
Reduction  of  color  by  mechanical  filtration  .  191 
Reduction  of  hardness  by  lime  treatment  of 

water 117 

Reduction  of  iron  in  ground  waters  ....  203 
Reduction  of  organic  matter  by  subsidence  .  117 
Reduction  of  sand-bed  by  scraping  .  .  182,  235 
Reduction  of  silt  by  subsidence  .  .  115,  116,  246 
Reduction  of  suspended  matter  by  subsidence,  246 
Reduction  of  total  solids  by  lime  treatment  of 

water 118 

Reduction  of  total  solids  by  mechanical  filters,  194 
Reduction  of  typhoid  rates,  Hamburg  ...  77 
Reduction  of  typhoid  rates,  Jersey  City,  N.J. .  34 
Reduction  of  typhoid  rates,  Lawrence,  Mass., 

36,37 

Reduction  of  typhoid  rates,  Lowell,  Mass.  .  36 
Reduction  of  typhoid  rates,  Newark,  N.J.  .33 

Refilling  of  filters 219,  234 

Regulating  valves  and  weirs  .  .  .  158,  209,  215 
Relative  dimensions  of  Hamburg  filters  .  .  210 
Relative  efficiency  of  filters  with  and  without 

alum 173,  198 

Renewal  of  sand-bed 161,  171 

Reservoirs  for  filtered  water 156 

Reservoirs  for  ground  waters 86 

Restoration  to  service  of  sand  filters  ....  133 

Rivers  as  carriers  of  sewage 17 

Rivers  as  sources  of  water  supply  .  .  .  .  15,  16 
Rivers  constitute  the  principal  sources  of  water 

supply 16 

Rotterdam,  filters  of 180 

Royal  Commission  on  Metropolitan  water  sup- 

Ply 4 

Salts  and  gases  in  solution  in  natural  waters,  121 
Sand  and  charcoal  filters  for  reduction  of  iron, 

203,204 

Sands  and  gravels,  selection  of 162 

Sand  scraped  and  washed  per  million  gallons, 

Hamburg 263 

Sand  scraped  and  washed  per  million  gallons, 

Lawrence,  Mass 262 

Sand  filters  of  London  water-works    ....      6 


PAGE 

Sand  filtration  in  Europe 131 

Sand-washing  machinery 213,  235 

San  Francisco,  typhoid  fever  in 102 

Saprophytic  bacteria 273 

Sarctna,  The 275 

Sault  Ste.  Marie,  Mich.,  epidemic  of  typhoid 

fever 99 

"  Schmutzdecke,"  The 7,  134,  184 

Schroder  sand-washing  machine,  220,  221,  222,  223 
Scraping  the  sand-bed  ....  212,  235,  261,  262 
Scraping  the  sand-bed  under  ice  ...  158,  224 
Seasonal  distribution  of  typhoid  fever  ...  66 
Seasonal  rotation  of  large  bodies  of  water  .  .  19 
Sedimentation  and  sand  filtration  in  Europe, 

140,  141 

Sedimentation  of  Chelsea  water 112 

Sedimentation  of  East  London  water  .  .  .  112 
Sedimentation  of  Grand  Junction  water  .  .112 

Sedimentation  of  Hamburg  water 208 

Sedimentation  of  Lake  Linthrathen  water  .     .  Ill 
Sedimentation  of  Lambeth  water   ......  112 

Sedimentation  of  Ohio  River  water, 

111,  115,  116,246 
Sedimentation  of  Polluted  "Waters     .     .  110 

Sedimentation  of  Thames  water 112 

Sedimentation  of  West  Middlesex  water  .  .  112 
Sedimentation,  time  allowed  for,  in  various 

water-works  of  Europe 141 

Seine,  The,  water  of 102 

Selection  of  sands  and  gravels 162 

Self-purification  of  sewage-polluted  streams  .  20 
Separate  services  for  sterilized  water  .  .  .  125 
Settling-basins  and  filters,  Hamburg  ....  208 

Sewage  infection  of  oysters 107 

Sewage  in  river  and  lake  waters 15 

Sewage  pollution  of  drinking-water  ....  98 
Sewage  pollution  of  navigable  streams  and 

lakes 98 

Sewage-polluted  water  and  disease  ....  8 
Sources  of  water  supply  in  driven  wells  .  .  82 
Species  of  bacteria  in  water  ....  132,  279,  280 
Spirilla  among  the  water  bacteria  .  .  276,  279,  280 

Spirilla  or  vibrios,  The 276 

Spore-bearing  bacteria 279,  286 

Spring    Water,   N.Y.,  epidemic    of    typhoid 

fever 96 

Staining  of  bacteria       281 

Stamford,  Conn.,  epidemic  of  typhoid  fever     .  107 

Standard  of  filtrate 190,  191 

Standard  of  food  quality 29 

Standard  of  successful  filtration      .    .     .    .    .    24 

Standard  of  water  quality 3 

Staphylococci,  J^he 275 

Staphylococcits  pyogenes  aureus 278 

Starting  a  filter  in  service 136 

Stas-Otto  method  for  reduction  of  toxalbumens,     62 

Sterilization  of  articles  of  diet 38 

Sterilization  of  Drinking- Water  ...  120 
Sterilization  of  filter  sand 165 


INDEX. 


303 


PAGE 

Sterilization  of  water  in  U.  S.  Navy  .  .  85,  128 
Sterilization  of  water  at  World's  Fair  .  .  .  128 

Sterilized  water  for  dietetic  uses 85 

Sterilized  water  on  ocean  steamships  .  .  85,  130 
Sterilizing  large  quantities  of  water,  cost  of  .  121 
St.  Louis,  Mo.,  epidemic  of  typhoid  ....  99 

Stone  disk  and  tube  niters 47 

Straining  action  of  sand  niters 132 

Streptococci,  The 275 

Storage  and  distributing  reservoirs  for  filtered 

water 156,  157 

Storage  of  filtered  water,  Lawrence,  Mass.      .  156 

Storage  of  filtered  water,  London 157 

Storage  of  filtered  water,  Paris 156 

Storage  of  filtered  water,  Quincy,  111.      .     .     .  157 

Storage  of  ground  waters 86 

Storage  of  surface  waters 87 

Storage  of  water  after  filtration  .  .  .  156,  157 
Storage  of  water  from  Anderson  Purifiers  .  .  182 
Source  of  water  supply,  Dresden  .  .  .  .  75,  88 
Source  of  water  supply,  Hamburg  .  77,  88,  208 
Source  of  water  supply,  Lawrence,  Mass.  .  .  88 
Source  of  water  supply,  Liverpool  ....  88 
Source  of  water  supply,  Munich  .  .  .  .  16,  88 

Sources  of  impurities  in  water 2 

Sources  of  infectious  disease 37 

Sources  of  naturally  pure  water 81 

Sources  of  water  supply 14 

Sources  of  water  supply,  Berlin  .  .  .  .  75,  88 
Sources  of  water  supply,  cities  of  Holland  .  .  75 
Sources  of  water  supply,  Copenhagen  ...  88 
Sources  of  water  supply,  driven  wells  ...  82 

Sources  of  water  supply,  London 88 

Sources  of  water  supply,  Paris 88 

Sources  of  water  supply,  Stockholm  ....     88 
Sources  of  water  supply,  Vienna     ...    5,  16,  88 
South  Bend,  Ind.,  ground  water  supply  ...     82 
South  Platte  River  as  a  source  of  water  sup- 
ply   106 

Submerged  sand  filter,  Zurich 96 

Subsidence  of  organic  matter  in  water    .       21,  140 

Subsidence  of  polluted  waters 140 

Subsidence  rate  of,  in  Ohio  River  water      .     .  116 

Sulphate  of  alumina  analysis 189 

Sulphate  of  alumina  and  free  flow 188 

Sulphuric  acid  in  filtrate 191 

Tastes  and  odors  in  stored  waters  ....  87 
Temperature  of  Hamburg  water  .  .  .  210,  220 

Test  for  alum  in  filtrate 190 

Test  of  Ohio  River  water  with  Parietti  solution,    50 

Tests  of  water  quality 31 

Tetrads,  The 275 

The  Hague,  filters  of 181 

Theory  of  alum  and  sand  filtration      ....  188 

Theory  of  liquefaction  of  gelatin 274 

Theory  of  sand  filtration    ...          ....  132 

The  Typhoid  Bacillus  and  Typhoid  Fever,  56 
Time  required  to  scrape  filter-beds  ....  226 


Time  required  to  wash  sand-bed 191 

Toxalbumens,  Stas-Otto  method,  reduction  by,    62 

Toxic  substances  in  bouillon 3 

Toxin  of  diphtheria 278 

Toulouse,  France,  filter  gallery 179 

Transmission  of  typhoid  by  Furlen  Brook  .  .  92 
Transmission  of  typhoid  by  River  Limmat .  .  96 
Transmission  of  typhoid  by  Mississippi  River,  100 
Transmission  of  typhoid  by  well  water  ...  93 

Treatment  of  polluted  waters 24 

Treatment  of  sewage 24 

Typhoid  bacillus, 

9,  11,  57,  275,  276, 277,  278,  280,  281,  282, 283 
Typhoid  bacillus,  identification  of,   56,  64,  278,  288 

Typhoid  bacillus,  longevity  of 17 

Typhoid  bacillus,  The,  in  water  supply  .  .  65,  67 
Typhoid  death  rates  of  cities  using  filtered  river 

water 23 

Typhoid  death  rates  of  cities  using  lake  water,  22 
Typhoid  death  rates  of  cities  using  river  water,  23 

Typhoid  fever  and  rainfall 105 

Typhoid  fever  as  a  measure  of  city  sanitation,  69 
Typhoid  fever  as  a  water-carried  disease  .  .  108 
Typhoid  fever  as  an  autumn  disease  ....  66 
Typhoid  fever  as  an  index  of  water  quality,  22,  70 

Typhoid  fever,  Denver,  Col 104 

Typhoid  fever  in  Hamburg  and  Altona  ...    68 

Typhoid  fever  in  San  Francisco 102 

Typhoid  fever,  loss  by,  in  large  cities  of  United 

States 109 

Typhoid  fever  rates,  Berlin  and  Rotterdam  .  139 
Typhoid  fever  rates,  Jersey  City,  N.J.  ...  33 
Typhoid  fever  rates,  Lawrence,  Mass.  ...  36 

Typhoid  fever  rates,  Lowell,  Mass 36 

Typhoid  fever  rates,  Newark,  N.J 33 

Typhoid  fever  rates,  Vienna  and  Munich  .  138 
Typhoid  fever  statistics  from  the  larger  cities 

of  Australia,  Canada,  Europe,  and  United 

States         .......   268,269,270,271 

Typhotoxin 62 

Types  of  mechanical  filters 185 

Types  of  Sand  Filters 158 

Tyrotoxicon 278 

Ubiquitous  nature  of  decomposing  or- 
ganic matter 16 

Undecomposed  alum  in  subsided  water  .  .  .  115 
Uniformity  coefficient  of  mixed  sizes  of  sand, 

164,  165,  172 
Uniformity  of  discharge  from  filters    ....  232 

Unpotable  water,  general  use  of 120 

Use  and  waste  of  water  in  German  cities  .  .  82 
Use  by  cities  of  water  from  driven  wells  .  82,  84 
Use  by  cities  of  water  from  mechanical  filters  .  89 
Use  of  coagulant  with  mechanical  filters  .  .  184 
Use  of  filtered  water  for  washing  sand  .  .  .  214 
Use  of  water  from  public  mains  in  large  cities,  89 

Vanne  water  (Paris) 83,  88,  102 


304 


INDEX. 


PAGE 

Vanne  water,  bacterial  contents  of  ....  243 
Variable  consumption  of  alum  with  mechanical 

niters 201 

Variation  in  counts  of  bacteria        40 

Variation  of  head  on  filter-beds 234 

Ventilation  of  closed  niters 235 

Vienna,  decline  oi  typhoid  fever  in  .  .  .  G7 
Vienna,  sources  of  water  supply  ....  5,  16 
Vital  products  of  putrefactive  bacteria  .  .  .  278 

"Warren,  Ohio,   judicial   decision   on   water 

supply 109 

Washing  and  storage  of  sand 235 

Washing  filter  sand  and  gravel  .  .  .  .  161,  213 
Washing  filter  sand,  water  required  .  .  2G3,  284 

Water  an  essential  of  health 1,90 

Water  and  food  as  distributers  of  typhoid  in- 
fection   68 

Water,  distrust  abroad  of  natural  sources     .     .    29 

Water  from  limestone  regions 14 

Water  from  the  Danube 5 

Water  from  the  River  Seine    .     .     .     102,  242,  243 

Water  from  the  sand  dunes 79 

Water  from  the  Vanne  Springs  ....     102,  243 

Water,  percentage  of  body  weight 1 

Water,  percenfage  of,  in  the  circulation  ...  1 
Water  required  by  Schroder  sand  washers  .  .  223 
Water  required  for  washing  sand,  Asbury  Park, 

N.J 264 

Water  required  tor  washing  sand,  Berlin  .  .  263 
Water  required  for  washing  sand,  Hamburg, 

263,264 
Water  required  f  orwashing  sand,  Keyport ,  N .  J .,  264 


PAGE 
Water  required  for  washing  sand,  Long  Branch, 

N.J 264 

Water  space  in  sand-bed 164,  232 

Water  storage  after  filtration 156 

Water  supply,  evidence  of  b.  typhosns  i:i  .  60,  288 
Water  supply  in  mountain  sources  ....  37 
Water  supply  in  the  Mangfall  Valley  ...  16 

Water  supply  in  the  Schneeberg 16 

Water  supply  of  Hamburg    .     .          ....     77 

Water  supply  of  Jersey  City,  N.J  .  .  .  32,  33 

Water  supply  of  Lawrence,  Mass 36 

Water  supply  of  Liverpool 81 

Water  supply  of  Lowell,  Mass 36,  37 

Water  supply  of  Manchester,  Eng.  .  .  .  5,  81 

Water  supply  of  Newark,  N.J 32,  33 

Water  supply  of  New  York  and  Edinburgh  .  76 
Water  supply  of  San  Francisco  ...  .28 

Water  supply  of  Vienna 5,  16,  88 

Water  the  cause  of  continuous  typhoid  fever 

rates  .  .  .  . 39 

Water  transmission  of  infectious  disease  .  .  9 
Welsh  sources  of  water  supply  for  London,  84,  118 
Winter  temperatures,  Cincinnati,  etc.  .  .  .  251 
Worcester,  Eng.,  purification  works  .  .  .  244 
Wurtz,  milk-sugar,  litmus  agar 103 

Yaryan  multiple  effect  sterilizer,  125,  127,  130 

Yield  of  filters  after  scraping  sand  .  .  .  227,  228 
Yield  of  wells  in  Germany 84 

Zurich  epidemic  of  typhoid  fever     ...    96 

Zurich,  filters  of 183 

Zymotic  disease,  prophylaxis  of 8 


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THIRTEENTH   EDITION. 

I  Vol.,  octavo,  644  pp.,  200  Illustrations,  fine  Cloth  Binding,  $5.00 


A  PRACTICAL  TREATISE 

WATER-SUPPLY  ENGINEERING 

RELATING   TO   THE 

HYDROLOGY,  HYDRODYNAMICS,  AND  PRACTICAL  CONSTRUCTION 
OF  WATER-WORKS  IN  NORTH  AMERICA, 

WITH    NUMEROUS 

TABLES    AND     ILLUSTRATIONS. 

BY 

J.  T.  FANNING,  CE, 

Member  of  tlie  A  merican  Society  of  Civil  Engineers. 


Thirteenth  Edition,  Revised,  Enlarged,   and  New  Tables  and  Illustrations  added. 


CONTENTS. 

SECTION  I.  Collection  and  Storage  of  Water,  and  its  Impurities. 
CHAPTER  I.  — Introductory.  CHAP.  II.  —  Quantity  of  Water  required.  CHAP.  III. — 
Rainfall.  CHAP.  IV.  —  Flow  of  Streams.  CHAP.  V.  —  Storage  and  Evaporation 
of  Water.  CHAP.  VI.  —  Supplying  Capacity  of  Watersheds.  CHAP.  VII. — 
Springs  and  Wells.  CHAP.  VIII. —  Impurities  of  Water.  CHAP.  IX.  —  Well, 
Spring,  Lake,  and  River  Supplies. 

SECTION  II.      Flow  of  Water  through  Sluices,  Pipes,  and  Channels. 
CHAPTER  X.  —  Weight,  Pressure,  and  Motion  of  Water.     CHAP.  XI.  —  Flow  of  Water 
through  Orifices.       CHAP.   XII.  —  Flow  of  Water   through  Short  Tubes.      CHAP. 
XIII.  —  Flow  of   Water  through  Pipes  under  Pressure.     CHAP.  XIV.  —  Measures 
of  Weirs  and  Weir  Gauging.      CHAP.  XV.  —  Flow  of  Water  in  Open  Channels. 

SECTION  III.      Practical  Construction  of  Water-Works. 

CHAPTER  XVI.  —  Reservoir  Embankments  and  Chambers.  CHAP.  XVII. — Open  Ca- 
nals. CHAP.  XVIII. — Waste  Weirs.  CHAP.  XIX. — Partitions  and  Retaining 
Walls.  CHAP.  XX.  — Masonry  Conduits.  CHAP.  XXI. — Mains  and  Distribution 
Pipes.  CHAP.  XXII.  —  Distribution  Systems  and  Appendages.  CHAP.  XXIII.  — 
Clarification  of  Water.  CHAP.  XXIV.  —  Pumping  of  Water.  CHAP.  XXV.  —Tank 
Stand  Pipes.  CHAP.  XXVI.  —  Systems  of  Water  Supply. 

APPENDIX.  —  Miscellaneous  Memoranda. 

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REPORT 


ON    THE 


FILTRATION  OF  RIVER  WATERS 

FOR  THE  SUPPLY  OF  CITIES, 

AS  PRACTISED  IN  EUROPE. 

MADE   TO   THE 

Board  of  Water  Commissioners  of  the  City  of  St,  Louis, 


JAMES  P.  KIRKWOOD,  Civil  Engineer* 


II. 

III. 
IV. 
V. 

VI. 

VII. 

VIII. 
IX. 

X. 

XI. 

XII. 

XIII. 

XIV. 
XV. 


BY    IPERMIISSICKN"    OF1    THE    BOARD. 


ILL USTRA TED  B  Y  THIRTY  ENGRA  VINCS. 


Report  on  Filtration. 

London  Works,  General. 

Chelsea  Water  Works  and  Filters. 

Lambeth  Water  Works  and  Filters. 

Southwark  and  Vauxhall  Water  Works 
and  Filters. 

Grand  Junction  Water  Works  and 
Filters. 

West  Middlesex  Water  Works  and 
Filters. 

New  River  Water  Works  and  Filters. 

East  London  Water  Works  and  Fil- 
ters. 

Leicester  Water  Works  and  Filters. 

York  Water  Works  and  Filters. 

Liverpool  Water  Works  and  Filters. 

Edinburgh  Water  Works  and  Filters. 

Dublin  Water  Works  and  Filters. 

Perth  Water  Works  and  Filtering  Gal- 
lery. 


CONTENTS. 

XVI.     Berlin  Water  Works  and  Filters. 
XVII.     Hamburg  Water  Works  and  Res- 
ervoirs. 

XVIII.     Altona  Water  Works  and  Filters. 
XIX.     Tours  Water  Works  and  Filtering 

Canal. 
XX.     Angers  Water  Works  and  Filtering 

Galleries. 

XXI.     Nantes  Water  Works  and  Filters. 
XXII.     Lyons  Water  Works  and  Filtering 
Galleries. 

XXIII.  Toulouse  Water  Works  and  Filter- 

ing Galleries. 

XXIV.  Marseilles  Water  Works  and  Filters. 
XXV.     Genoa  Water  Works  and  Filtering 

Galleries. 

XXVI.     Leghorn    Water    Works    and    Cis- 
terns. 

XXVII.     Wakefield  Water   Works  and  Fil- 
ters. 


APPENDIX. 

Instructions,  Tables  of  Equivalents  of  Measures,  London  Pumping  Engines  Tabulated,  Boil- 
ers of  Pumping  Engines  Tabulated. 


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SECOND   EDITION. 

One  Volume,  8vo,  Cloth,  Illustrated,  600  Pages.     Price,  $6.00. 

SEWAGE  DISPOSAL 

IN  THE  UNITED  STATES 

By  Geo.  W.  Rafter,  M.  Am,  Soc.  C  E.,  and  M.  N.  Baker,  Ph.  B.,  Associate 
Editor,  "  Engineering  News." 


CONTENTS. 

PART  I.  — DISCUSSION   OF  PRINCIPLES. 


CHAPTER 

I.     Preliminary  Discussion. 
II.    The  Infectious  Diseases  of  Animals. 
III.     On  the  Pollution  of  Streams. 
IV.    The  Self-Purification  of  Running  Streams 
and  the   Rational  View  in   Relation  to 
the   Disposal  of   Sewage   by  Discharge 
into  Tide- Water. 

V.    The  Composition  of  Sewage  Muds. 
Legal  Aspects  of  the  Case. 
Quantity  of  Sewage  and  Variation  in  Rate 

of  Flow. 

General  Data  of  Sewage  Disposal. 
Discharge  into  Tidal  or  other  large  Bodies 

of  Water. 

On  Nitrification  and  the  Nitrifying  Organ- 
ism. 


VI. 
VII. 


VIII. 
IX. 


X. 


CHAPTER 

XI.     Chemical  Precipitation. 
XII.     Broad  Irrigation. 

XIII.     On  Silos  and  their  Use  in  Sewage  Farming. 
XIV.     Intermittent  Filtration. 
XV.     Sub-surface  Irrigation. 
XVI.    The  Disposal  of  Manufacturing  Wastes. 
XVII.     On  the  Temperature  of  the  Air  and  of 
Natural     Soils,   and    its    Relation    to 
Sewage  Purification  by  Broad  Irriga- 
tion and  Intermittent  Filtration. 
XVIII.     On  Beggiatoa  Alba  and  its  Relation  to 

Sewage  Effluents. 

XIX.    The  Effect  of  the  Pollution  of  Streams 
by    Manufacturing    Wastes   upon   the 
Life  of  Fish. 
XX.     Conclusions  to  Part  I. 


CHAPTER 
XXI. 

XXII. 
XXIII. 

XXIV. 
XXV. 

XXVI. 

XXVII. 

XXVIII. 

XXIX. 

XXX. 

XXXI. 

XXXII. 


PART  II. -DESCRIPTIONS  OF   WORKS. 

CHAPTER 


Pail  System  at  Hemlock  Lake,  New 
York. 

The  Fullerton  Avenue  Conduit  and 
the  Bridgeport  Pumping  Station, 
Chicago. 

Chemical  Precipitation  Plants  at  Coney 
Island,  Round  Lake,  White  Plains, 
and  Sheepshead  Bay,  New  York. 

Chemical  Precipitation  and  Filtration 
at  East  Orange,  New  Jersey. 

Chemical  Precipitation  and  Mechanical 
Separation  at  Long  Branch,  New 
Jersey. 

The  Mystic  Valley  Chemical  Precipita- 
tion Works. 

Chemical  Precipitation  at  Worcester, 
Massachusetts. 

Discharge  into  Tide-Water  and  Pro- 
posed Chemical  Precipitation  at 
Providence,  Rhode  Island. 

Broad  Irrigation  at  the  State  Hospital 
for  the  Insane,  Worcester,  Mass. 

Broad  Irrigation  and  Intermittent  Fil- 
tration at  Pullman,  Illinois. 

Broad  Irrigation  at  the  Massachusetts 
Reformatory,  Concord. 

Broad  Irrigation  at  the  Rhode  Island 
State  Institutions. 


XXXIII.  Intermittent  Filtration  and  Broad  Ir- 

rigation   at    South    Framingham, 
Massachusetts. 

XXXIV.  Intermittent  Filtration  at  Medfield, 

Massachusetts. 

XXXV.  Intermittent  Filtration  and  Broad  Ir- 
rigation at  the  London,  Ontario, 
Hospital  for  the  Insane. 

XXXVI.     Chemical  Precipitation  and  Intermit- 
tent  Filtration  at   the   Rochester, 
Minnesota,  Hospital  for  the  Insane. 
XXXVII.     Intermittent   Filtration  at  Marlbor- 

ough,  Massachusetts. 

XXXVIII.  Intermittent  Filtration  at  the  Massa- 
chusetts School  for  the  Feeble- 
Minded. 

XXXIX.     Sub-surface  Irrigation  at  Lawrence- 

ville,  New  Jersey,  School  for  Boys. 

XL.     Intermittent   Filtration  at  Gardner, 

Massachusetts. 
XLI.     Intermittent   Filtration  at  Summit, 

New  Jersey. 

XLII.     Land  Disposal  at  Hastings, Nebraska. 
XLIII.     Surface  Irrigation  at  Wayne,  Penn- 
sylvania. 
XLIV.    The  Use  of  Sewage  for  Irrigation  in 

the  West. 
XLV.     Miscellaneous  Plants. 


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