Los Angeles daily herald., 1889-08-20
Sure Method of Purifying Sewage.

Sure Method of Purifying Sewage.
EDITORS HERALD-The date set for
voting on the outfall sewer bonds being
near at hand, and having noticed quite q
good deal of discussion on this subject
through the public prints of this city, l
am surprised that no one has brought
forward the new method of treating sew
age matter which has been tried in
London, and, so far as these experiments
60, has proved very successful, both in
point of cheapness and efficiency. This
process is accomplished by electrolysis,
and, while being very simple, as every
one familiar with electrolytic action must
know, is thoroughly effeetual. This
method, as applied, would, perhaps, be
best understood by quoting from an
article in the Medical and Sur.
gicol Reporter, Philadelphia, June %,
1889, taken from Science April II, 1889
"The plan proposed by Mr.. Webster for
the publication of sewage by electro
lytic methods, has been tried on q large
scale, and with encouraging results. The
process is very simple, and is described
by the London Electrician as follows
The color, density and constitution of the
London sewage varies from hour to hour
in the most extraordinary manner; but
the first sample to be dealt with Was of a
light yellow color, looking something like
weak tea with little milk in it, but, 80
far as could be seen, it contained very
little solid matter in mechanical suspen-
sion. This having been poured into q
test jar, q current was passed through it
between a pair of iron electrodes, with
about six volts electro motive force. An
extremely rapid effect was produced. In
less than two minutes the jar was seen
to be filled with focculent preci pitate
which was gradually carried upward by
the bubbles Of liberated hydrogen. After
about three minutes the electrodes were
withdrawn and the precipitate left to
collect at the top. In actual practice,
after the ef1uent has passed into the
settling-tank, the precipitate, in the
course of about two hours, loses the
whole OF the entangled by drogen; it
then sinks to the bottom of the tank.
The sludge thus formed is similar to that
produced by the chemical process now
in use, except that the electrical method
possesses the obvious advantage that
the total quantity of material has not
been increased by the addition of chem
icals.' But, besides this precipitation,
there is an action on the organic matters
in solution which robs them Of their un.
pleasant and harmful properties. In
the larger experiments, carried on
at Crossness, two 20,horee power
engines are used, with an Edison. Hop
kinson dynamo. Iron plates are placed
in the shoot through which the sewage
is discharged. In travelling along the
shoot, every particle of the sewage comes
in contact with the plates, and finally
the whole is received into the settling
tank. With TWEEN y-seven horse power,
it IL possible to treat million gallons of
sewage in twenty four hours. The con-
sumption OF iron in actual working is
about two grains per gallon. Taking a
town with a daily flow of ten million
gallons OF sewage a day-corresp )nding
to population of about 300 000-the
consumption of iron should not exceed
304 tons per annum, and the steam
plant required would be about 250 horse
power. This plant takes the place of the
mixing-tanks, machinery, and chemicals
employed in the chemical process for the
publication of sewage; aud, il such cleo
tricaI plant is designed to meet the require
ments of the district, it should cost less
than any other method, besides precipi-
tating and purifying in one operation.
have thus quoted in full this process
as described in order to show that
1t must be success, and af'er a careful
study of this subject am fully convinced
that this is the method that Les Angeles
should adopt in disposing Of it's sewage
for believe that it is pretty
generally conceded that this sewage could
be utilized for irrigatiug purposes for per-
haps eight months out of every twelve,
if It can only be rendered iunocuous and
in a condition in which people can util
ize it without any risk to health while
during the rainy season this excess could
be allowed to mingle with the surface
water, and find its way into the sea, as
as any ordinary water, and with
out any detriment to citizens of Santa
Monica, or any other town on the beach.
Los Angeles is certainly more favorably
situated for thus utilizing its waste matter