The record-union., 1891-05-27

100 feet by 66.67 feet each, and feet deep.
The central channel was then built with
pipe arch. The side walls of the arch
are of stone, in cement mortar, twenty
SIX inches thick. The arch is of three
courses OF brick and the foundations are
OF cement mortar. The pipe is sur
rounded with cement mortar and abso-
lutely water-tght. Opposite the center
OF each tank is side arch, extending to
the end walls of the tank. In these are
laid the
EMPTYING PIPES,
Also the drain connecting the main
Sludge drain below the central channel(.
with the drain in the tanks, so that every
foot OF pipe and drain can be examined
except where they pass through the
walls. The sludge well is ten feet in
diameter and eight feet deep. 1t was ex-
cavated in quicksand and laid in brick
and cement. Next the channel to con-
Duct the sewage to the tanks was built,
but 1t is not necessary to describe its
construction in detail 1t lies between
the two tiers of tanks and feeds each of
them. The mouth of the outfall sewer is
divided into four parts, receiving
chamber, Is feet by feet; two screen
chambers, 10 feet by SO feet the outlet
chamber, Is feet at one end, $40 at the
other and Z feet long.
THE GATES
Controlling the flow ofsewage are of wood.
the screens of flat iron, with half-inch
spaces. The mixing channel runs from
the screen chamber to the inlet weir of
the first tank. The overflow steps and
ettluent drains complete the structure.
The tanks cost 5000. The power used
is sixty power Brown engine
The buildings at the edge of the tanks
arc OF wood. Here are the agitators for
mixing the chemicals to discharge into
no -i,,fr Il
watts, elliptical i'll shape, 5xS, and seven
feet deep. In each vat is perpendicular
shaft, with horizontal arms, to mix the
ingredients thoroughly. On the main
floor is the we'll. Into it crude sewage is
run TO supply mixing water. It is
pumped in for that purpose by centri-
fugal pump. In the basement is
THE sLUDGE WE'LL
And centrifugal pump for pumping
the sludge. The second floor is used for
chemicals, for lime crusher, scales and
4 hopper into which the crushed lime is
discharged, after being sifted by a revolv-
ing screen on the third or upper floor
Since the works began they have treated
3,0O0,0P gallons OF sewage daily.
THE PROCESS.
''The sewage. after leaving the outfall
sewer, enters the receiving chamber in
the gate or screen house. 1t then passes
through the screens, where all matter
that would tend to clog the sludge pump
are taken out, such as paper and sticks
of wood. 1t then passes through the out
let chamber into the mixing channel.
The chemicals are introduced at the upper
end OF the channel, being discharged
through pipe connected with the watts in
side the building. After the introduction
OF the chemicals the sewage flows through
the mixing channel, the chemicals being
thoroughly mixed with it by the agitation
produced by battle plates. From this
channel the sewage passes through the
first weir into tank No. l. Here there is
q fall of one foot, which tends to more
thoroughly mix together the sewage and
chemicals; it then passes very SLOWLY
through tank l, out OF this tank through
the second weir into tank 2, through tank
2 into tank 3, and thence through tanks 4,
D and 8, until il is discharged finally
through the last weir and over the over
flow steps into the effiuent drain, and
from thence into the river; it takes about
six hours for it to pass through all the
tanks"
CLEANING TANKS.
When it is needed to clean a tank. flash
boards are placed so as to cut it off and
and send the sewage around into another
tank through the same channel The
tank is allowed to rest from three to six
hours. Then the water is drawn off into
the river. The sludge-gate is then
opened and the sludge settled on the bot
tom flows to the sludge well. Here
treated, 1t is then pumped into pipe
carrier to sludge beds, or lands owned by
the city, and isolated. There are eleven
sludge beds, 100 feet square, on this low
land. The turf was removed and one
days sludge pumped upon each bed.
There 1t rests eleven days. Occasionally
a layer of gravel is spread over it, the
1ar I.iTo To do rNla l.,
erect
A INSTRUCTOR
For the burning ofthe sludge. This is
not costly furnace but its operation will
slightly increase the cost Of the sewage
disposal, now given at So, 800 for Wor-
cester, with its 81, 600 of population. Mr..
Allen says OF the precipitation that it
takes place principally in the first three
tanks. From one and two the sludge has
to be removed every thirty-six hours in
warm weather. Tank three is cleaned
every two or three days in warm weather,
and every seven or eight in cold weather
In tanks one and two in warm weather
in thirty-siX hours the sludge is about
ten inches deep over the entire bottom
No. 3, when cleaned once III three days,
has eight inches of sludge, and four, five
and six, cleaned once u week, have SIX
inches. The sludge is 50 per cent. water.
Spread upon the beds, it evaporates in
nine days The lime used is Vermont. |
and costs 81 atom; the sulphate of alumina
costs S25 a ton, delivered. The number
of grains per gallon used varies from 100
to 200 Of lime, and one to forty of alumina,
owing to change ofthe character of the
sewage, as created at the manufactures
using acids.
THE EFFLUENT,
Or the water flowed off after the sewage
is chemically treated, is free of all sus-
pended matter; the organic matter car
ried in solution is very largely reduced,
and the free and albuminoid ammonias
are also largely reduced. No decompoSi-
ton takes place in the eflluent, and there
is no more injury to the river than would
be from so much spring water.
THE COST.
Mr.. Allen says: GAS to the cost of treat
ment, it will he more satisfactory to wait
for another years run of the works. The
cost is being constantly reduced, and at
present is well within the estimate made
by me several years ago-namely, So, 500
per year."
found out and accomplished at Worces-
ter. Two things are clear:
THAT AT SACRAMENTO
We would be at less cost for delivery of
the sewage and about the same cost for
construction of the works: that our sit
uation is similar to that at Worcester-we
must discharge into the river. There is
no other way open to us except to erect
pipe line from the city to Snodgrass
Slough and lift all the sewage into that,
with sufficient water to flush it to the
exit, while storm water we could pump
into the river or the drain. II any one
thinks this plan can be carried out short
of two or three hundred thousand dollars
he is sadly mistaken, even assuming that
right of way can be had free and that no
risk is taken of having the discharge into
the slough eventually enjoined.
1t would seem, therefore, since over
fly nitinS of E,ncland tx.-nratx