The weekly Republican. (Plymouth, Ind.) 1911-1922, 1911-06-01
PURIFICATIOV METHODS
Great Capacity of Improved Filters
Increasing Population of Cities
Makes Demand For
Machinery.


towns becomes more and more con-
gested, the public health requires
that some methods be adopted that
will change the chemical composition
of the sewage so that it will not
putrefy when discharged into water
courses. In some places it is even
necessary to disinfect the sewage so
that all disease germs will be de-
,sfroyed. Disinfection is demanded
because of the possible pollution of
water supplies and of shellfish beds.
The methods adopted for sewage dis
infection are described at length in
a publication issued by the United
States Geological Survey as Water
Supply Paper 300, entitled "The Dis
Infection of Sewage and Sewage Fill
ter Efluents.' by Earle B. Phelps.
Sewage publication as practised
today IS but the artificial and inten-
sive application of the processes. used
everywhere by nature TO reduce put
rescible organic matter to inert inor-
ganic matter. 1t is well known that
if any organic matter such as earb-
age or dead animal is left exposed
upon the ground, it putrefies or rots
for a considerable period. giving off
nauseous odors in the meantime. AZ
ter a while the rotting Is complete.
the odor disappears, and the material
becomes mineral matter exclusively.
The process is scientifically defined
by saying that the organic matter
has become oxidized. that is. oxygen
has united with the organic matter to
produce the desired result. The pro-
cess of sewage puria cation is precise
ly the same except That in the puri.
fication work conditions are provided
under which nature is assisted in her
work and the result is accomplished
In a much shorter space of time.
Great Capacity of Improved Filters.
The improvements made in methods
of treating sewage Rave therefore
not involved the discovery or APP
plication of new principles; those
established since the world began
are utilized. The constant aim of
the experimenters has been to in
crease the rate at which sewage can
be purified. From the old-time sewage
irrigation field, with its maximum
capacity of purifying possibly TO-
coo gallons sewage on an acre in "a
hours. to- the present-dav trickling
filter capable of dealing with two or
three million gallons a day on an
acre of filter surface, the march Of
improvement has been steady and
continuous.
The later investi ators have found
that efficient publication can be
accomplished without carrying the
process to the point of complete OK
idation. The liquid flowing from a
modern tickling filter, according to
Mr.. Phelps, looks 20 the unstrained
eve like the original savage indeed
there is almost as much organic
matter in the effluent as in the raw
sewage, and sometimes more, but
this orgaic matter has been suffici-
emily changed or oxidized to rob it
of its foulness. In other words, its
chemical composition has been so
altered that it is no longer capable
of UNDERGOING rapid putre active
decomposition.
Although it may appear incon-
ceivable that the chief object of W.
age purifcafion-prevention of the
fouling of streams-can be attain
cd by such invisible changes in the
nature of the organic matter, never
theless the discharge from efficient
sewage-disposal plants may be per-
united to enter a stream without
fear of causing a nuisance. The
work of publication also proceeds
in the stream itself, as it does in
the soil and in the publication
works, until the oxidation is com
plete- Oxygen for that purpose +
sufficiently abundant in . reason
ably clean stream, but If the Stream
is overloaded with putrescible sew.
age there will not be oxygen enough
and the stream will become putrid
If all the putrescrible organic matter