Montour American. (Danville, Pa.) 1866-1920, 1909-10-07
DISPOSAL PLANT
IN COMMISSION

The sewage disposal plant at the hos
pital for the insane is now completed.
The average flow of sewage-about 25O
gallons per minute-which was form
erlv discharged directly from the in
stitution into the river is now subject
ed to the process of publication and
the effluent III corresponding quantity
clear water, from which apparently
bacteria and impurities have been
eliminated-alone finds its way into
our water supply.
The full completion of the sewage
disposal system at the hospital for the
insane marks the beginning OF an
epoch in local history that the people
of Danville have been looking forward
to for many years. The scheme of sew
AGE treatment adopted is known as the
bacterial or biological system and is
combination of settling and filtration.
The plant is we'll worth II study at
close range and those who desire to see
n demonstration of the system can not
do better than to pay the institution "a
visit. In several respects the plant is
marvel.
Not the least remarkable feature is
the fact that the whole system-the
pumping station with its complex
machinery and the septic tanks and
filter beds on the hill 1000 feet away
operates automatically and that one
man in half an hour daily can give 1T
all the attention it needs 1t is this
automatic feature that renders the
plant comparatively inexpensive in its
operation.
The first point that attracts the Wis
itor is the pumping station situated in
the ravine west of the hospital In the
we'll are set three automatically con-
trolled electrically operated sewage
pumps, which force the sewage up in
to the field above the farm house. The
pumps are set in triplicate to make ac-
ton certain at all times and are so
connected electrically that when sew
| age IlSCS W al llhCNl ilOASiAN III WV WA
an automatic switch is thrown by
means of a float and one of the pumps
starts up. When the well becomes
empty the pump automatically stops.
The pumps, which were manufactur-
ed by the Morris Machine works, are
known as the open impeller centrifug-
al pump, such as are used in all large
cities where pumping of sewage is re-
quired. The pumps were specified to
have a capacity of AT gallons per min
ute. Tests made, however, show each
pump capable of handling $50 gallons
of sewage per minute.
The motors are of the Westinghouse e
standard, type Fare vertical and of
20 horse power. The power for operat-
ing the motors is furnished through a
cable extending from the old power
house to the pumping station where 1t
connects with the switchboard.
The pumps can be alternated No.
pump. set to the low level, is found to
be sufficient for the present flow of
sewage The others are held in reserve
to be used in case of accident or in the
future should the hospital be enlarg-
ed.
After the sewage reaches the plant
it first passes through the screen or
grit chamber where the coarse mater
ial is taken cut. The sewage then
passes very slowly through three very
large settling or septic tanks 50 feet
, long, 16 feet wide and feet deep. In
these tanks perhaps 30 per cent. of the
suspended matter settles and form of
fermentation, or more properly putre-
faction caused by bacteria takes place,
all being part of the process of puri-
fication. This septic action is nothin z
more than the sedimentation or settl-
ing with accompanying publication
that takes place in ordinary stagnant
pools. There is no system of sewage
disposal that does not involve the use
of the septic tank in some form or an
other.
The three septic tanks act independ-
emily of each other. AS the suspended
matter settles the clear water flows out
to the filter. Provision is made for
cleaning the settling tanks and draw
ing off the heavy matter or sludge on
to sand filter.
The floor of the settling tanks are
higher than the top of the filter, the
area of which is little less than a
quarter of an acre. The filter bed is six
feet deep and is composed of pebbles
and broken stone from one inch to 4
inches in size. Terra Gotta pipe un-
derdrains are laid beneath the filtering
material. These draw the water from
the body of the filter to drainage chan
nels on the side These drainage pipes
in the bottom also admit the air which
circulates through all the innumerable
interstices of the filter bed.
The water from the settling or sep
tic tanks, flows into dosing" tank
holding 2500 gallons. As the tank fills
up a syphon set in it discharges the
sewage on the filter through fifty-four
spraying nozzles The water rs it is
sprayed into the air on the filter bed