The Leavenworth echo. [volume] (Leavenworth, Wash.) 1904-current, 1913-06-13
THE PURIFICATION
OF DRINKING WATER
U. S. Geological Survey issues a Report
Describing Practical Methods of
Handing Public Water Supplies

A simple, direct description Of meth
DDS Of purifying water for drinking is
given in a report by George A. John
son, just published by the United
States Geological Survey. The report
describes the various types Of water
supply systems used BY cities in the
United States, sets forth the principal
advantages and disadvantages OF each,
and gives brief history of the devel-
opment of waterworks systems and the
effect of their installation on the health
OF communities.
The necessity for purifying water
for use in cities is clearly shown, not
the least important value of water puri-
fication being the insurance it provides
against disease. Mr.. Johnson shows
by very reasonable estimates that the
use OF pure water annually saves from
the ravages of water-borne typhoid
fever alone more than four times the
cost OF purifying the water. The sub
stitution of pure for impure water sup
plies in the United States would save
annually some 100000, 900 and fully
$4,000 lives.
The paper includes a historical
sketch Of modes or systems OF water
publication, from the storage works
and Qualification by alum used by the
ancient Chinese to the present-day
methods Of filtration, coagulation, and
sterilization. Preparatory treatment.
in which the water is passed through
sedimentation tanks, coagulation ba-
sins, or roughing filters to remove a
portion Of its color or turbidity, is dis
cussed in detail.
In slow sand filtration water is passed
slowly through great beds of fine sand,
on which it leaves its impurities. Il
Illustrations of several slow sand filtra-
ton plants are given and special fea-
lures Of construction, sand-handling,
sand-washing, and operation are ex-
planned and discussed. The costs OF
construction and of maintenance and
operation are shown in detail for q
number of plants Of this type. The
report also describes and illustrates in
similar manner rapid sand filters,
which differ from slow sand filters
chiefly in being constructed in smaller
units and of coarser sand, in always
having coagulation as preliminary
treatment, in being operated about
40 times as fast, and in being cleaned
by sending a reverse current Of water
through the filters.
The softening OF municipal water
supplies in connection with their puri-
fication is discussed and the advantages
and limitations as well as the details OF
this treatment are set forth in in
structive detail. Hard waters produce
scale in and shortens the life of boilers,
causing waste Of coal. They are i'll
suited to the needs of many water-us-
ing industries and cause an enormous
waste OF soap in laundries and in ordi-
nary domestic operations. In many
instances the saving Of soap is alone
sufficient to pay the costs of soitening.
In this report technical terms have
been avoided so far as possible and the
subject-matter is presented SO clearly
and concisely that it can be readily
understood by the nontechnical reader.
T. CONTAINS youch inform ation nf value
to city officials, boards of health, and
others interested in sanitary engineer
ing as applied to waterworks planning,
construction, maintenance, and opera
ton. 1t is published as Water-Supply
Paper 315, and a copy can be OBJ
tanned free of charge on application to
the Director, United States Geological
Survey, Washington, D. c.