The record-union., 1893-07-06
A NEW AND CHEAPER SEWAGE DIS
POSAL DEVICE.

The chemical precipitation method of
disposing of sewage is the means en-
ployed at the Worlds Fair for treatment
of the sewage of grounds occupied by
dred and fifty thousand people daily. The
machinery employed differs, however,
from that in use at Worcester, Mass 1t
would appear to be cheaper, since it has
capacity of six thousand gallons min
ute and costs complete but 81, 900.
At Worcester the sewage is discharged
by an outfall sewer into a precipitating
settling tank, and thence successfully
into three others, where the matter is
treated. The sludge finally settled, is
taken out from the last Of the tanks. the
atfiuent being drawn off. The sludge is
then cut, pressed and disposed Of as
fertilizer or is dried and burned.
At the Worlds Fair the process is to
convey the sewage to tanks, each being
vertical and fifty feet deep by diameter
of thirty-two feet. In the center of each
is a thirty-foot pipe six feet across,
and at its base are pipe arms radiating in
eight directions to the sides of the tank.
In the midst of the tanks is a center stand
pipe sixty feet high and three feet in di-
ameter, with drum sixteen feet in hight
and eleven feet wide. with strainer on
top This drum is tapped by four four
teen-inch pipes conducting the sewage to
the vertical pipes in each tank. Above
each tank are tubs with aluminium sui
phate and lime.
The sewage is conducted to the drum
of the central stand pipe and overflows
the strainer, and thence goes by the four
teen-inch pipes to the tank stand pipes.
and through the radiating arms of which
it is distributed through the tank.
The chemicals are added and mixed in
en- route. The solid matter settles to the
bottom of each tank, having en- route
been thoroughly mixed by its travel and
by mixer devices. The liquid rises OF
course to the tops of the tanks, and over
flows into troughs which convey the
purified water away. Each tank has at
its base gates. through which the water
pressure slowly forces the sludge into
cylindrical tanks. When one is full it is
disconnected, and an air pump presses
the matter in it into cakes one and halt
inches thick by three feet in diameter.
These cakes are then either sold for
fertilizing purposes or are burned in a
furnace.
This apparatus treats $3.50, 600 gallons of
sewage every twenty-four hours at a cost
Of S. for chemicals per each 100000 gal
Ions. From six to eight men are required
to work the plant, and the entire area oc-
cupied by it is but l0Ox125 feet.
1t will be seen that this $4,000 plant,
exclusive of the shelter building, which
need be but simple, coarse structure,
with open sides, would be more than suf.
ticient to answer the necessities Of Sacra.
mento for very many years to come.
Now, when chemical disposition Of
sewage has been brought down to such
cheapness, and can be introduced for So
low a cost, is there any reason whatever
for Sacramento delaying any longer in
adopting new sewage disposal systemi
Of course, no matter what is done, the
construction of an outfall sewer, and the
conduct of natural drainage in gutter
mines to keep it out of sewers, are separate
considerations. Their cost, therefore, anc
the cost of the rectifcation of old sewer
lines are to be met anyhow. But SO fal
as sewage as we have it is concerned,
we may begin to dispose of it at once and
with a plant, the cost of which is eompar
ativelv light 1t could be erected now
and the sewer system related to it as rap
idly as may be. Even at the outset very
considerable number of cess-pools coulC
be abandoned along the lines OF mair
savers. The sooner Sacramento enters
upon this work the better once estab