The Telegraph-courier. [volume] (Kenosha, Wis.) 1888-1946, 1896-11-26
NEED OF PURE WATER
A VITALITY IMPORTANT SANITARY
PROBLEM.

The most vitality important sanitary
problem confronting American munich
palities at the present day is unques-
tionably the supply Of pure water for
drinking and other domestic purposes
The widespread prevalence of typhoid
fever may be practically looked upon as
a measure Of the pollution of the drink
ing water. Depending as this disease is
almost entirely upon an infected water
supply, the importance of having the
latter Of a pure quality is self evident.
! In 1894, 30 Of the principal cities of the
United States had an average typhoid
mortality of 80. 6 per hundred thousand
of population. Those cities which had
the largest mortality from this disease
were supplied by highly suspicious
quality of drinking water.
In epidemics of cholera a similar re-
lation exists between the outbreaks and
extension of the disease to an infected
water supply. Aside, however, from the
production of these specific diseases,
pure water or water free from all sort
of uncleanliness is demanded by the
sanitary conscience of the public.
These premises being conceded, the
great Importance Of securing a supply
Of drinking water free from contamina-
ton becomes apparent.
In sparsely settled districts, or where
a supply Of unpolluted water can be
brought from distance to large com
munity, it will probably be better to
secure such pure supply rather than
purify a source of supply which has
been polluted, but in the majority of
instances, particularly in the eastern
and central sections of this country, the
procurement of such an unpolluted sup
ply is practically barred by financial
considerations.
Fortunately there is at our hand,
however, means by which q source of
supply once polluted can be again rem
dered pure; this is filtration.
Formerly filtration simply meant
straining out from water all gross i'm
purities and changing adirty or muddy
water into clear and limpid fluid. It
did not contemplate the changing of
organic compounds into inorganic COM
pounds Or the removal from the water
of minute organisms, which we have
| learned to regard as causes of specific
diseases. Our notions of what consti-
tutes publication of water have cOnsid-
erably changed. We now know that
water may be perfectly clear and linn
pid and yet be extremely impure by
reason of it's content of impure organic
matter or dangerous micro organisms
The results obtained by the filtration Of
sewage, III which a highly impure
! liquid full of organic matter and tenn
ing with micro organisms of various
kinds, is rendered clear, limpid almost
entirely free from organisms and or
ganic matter, have taught US how to
purify polluted water, which in many
instances is simply a highly diluted
sewage.
The real filtration does not take place
in the sand, but by deposit from the
still unpurifed water a layer of mud
is formed on the top of the sand. and
this layer of mud which is over the
sand is the real filter which retains
the suspended constituents from the
water In the process of filtration the
important point is first that proper
layer of slime should be formed, and
that it should not be disturbed during
the process of filtration, and that when
by further continuous deposit it becomes
too thick and therefore too impermeable
to water it should be removed.
According to all appearances, different
natural waters are capable Of producing
the fltering mud layer in very different
degrees, according to the amount Of
mineral and vegetable matter held in
suspension. Some river waters which
are especially rich in clayey constitu'
ents can deposit good fltering mud
layer in eight or ten hours. Other kinds
of water rendered more turbid by vege-
table matter require longer time. at
least "a hours, to form the deposit. At
certain periods of the year, especially
! at the time of the so called water
bloom, owing to the appearance of in
Vulnerable microscopic alg9, the vege-
table constituents suspended in water
are increased to an extraordinary extent
and are of a particularly Shiny char
acter and form, therefore, layer which
in few days becomes nearly imperme
From these brief remarks it will APP
pear that in sand filtration we are not
dealing with so simple matter as is
often supposed. 1t has also been discov-
cred that in the gradual wearing out Of
the sand layer it should never be al
lowed to get below a certain thickness,
about 80 centimeters, and that a certain
speed, about 100 millimeters in the
hour, must be allowed for the move
ment Of the water through the sand
layer to obtain the most perfect purif-
cation.
| Koch further states that daily or
triweekly bacteriologic examination of
! the filtered water must be made in order
to test the performance of the filter.
''If filter works satisfactorily in every
respect, experience shows that there
will be found less than 100 germs ca
pable of development in one cubic CEN
of xr,o&o,. ov,1 chic ic cr1nctiUn