The Fargo forum and daily republican. [volume] (Fargo, N.D.) 1894-1957, 1912-02-12

40 AuAA1lB DIT Ills uAdAILlutu phIt
Purifying the Water.
At the farther end OF the chamber
the water passes through q sluice
gate to sedimentation basin No. 1.
This basin has a capacity of over L.
100000 gallons and is of sufficient
cross section so that the water flows
through 1t al a. very slow velocity. AS
the water passes but of the mixing
chamber a ~coagulent, which may be
either suiphate of iron or sulphate OF
alum is added to the water in order
to form what is known as flock"
This flock in the water has something
the appearance of falling snow on a
very quiet day, and may also be conn
pared to wool. This flock tends to
gather the small particles of clay, and
also immeshes within its folds the
bacteria or animal life contained in
the water. This bacteria is a low form
of animal life, the removal of which
constitutes one Of the main objects OF
water publication.
The very low velocity of the water
in the sedimentation basins allows the
lime to complete its softening action,
and allows the flock to settle to the
bottom of the basins. The flock is a
very ligh fluffy material and varies in
different waters according to the al
kalinity in the water or the turbidity
therein contained. In these basins
color and odor and other deleterious
properties Of the water are removed.
After leaving the s-edimentation bA-
sin No. /, the water may be directed
into two channels, first, it may be
conveyed directly into the filters, il 1t
is concluded that sufficient time has
elapsed for the softening, or second,
it may be conveyed through a conduit
to sedimentation basin No. 2, which
has about % per cent greater capacity
than sedimentation basin No. /, and
the water passes through this basin
in order to complete the chemical
reactions. When the water contains
a great deal of turbidity or when the
water is very hard, or when the con-
large, as 1t is in the summer, basins
No. / and 2 may be used in series,
In ease it is desirable to cut out the
mixing chamber, basin No. 2 can be
used without using No. /. The two
basins a be used in parallel il nee
essary, only s~oftening part Of the wa
ter. 1t is sometimes important and
necessary to add raw water to the
softened water in small amounts, in
order to prevent after deposits in the
water pipes leading to the city.
Every possible contingency and
necessity have been provided for in
this plant in order that every change
may be made in the water, and the wa
ter properly treated. Each one Of the
sedimentation basins are so feet by $50
feet in area by 10 feet deep. They are
constructed of reinforced concrete. The
walls are set in substantial concrete
foundations, and the floor of the ba-
sins are Of reinforced concrete. The
roof Is constructed of reinforced con-
crete and is ten inches thick. Suitable
manholes are constructed at various
points of the roofing for the purpose
of allowing the workmen TO clean out
any material necessary, or in order to
examine the basins. Two feet of earth
will be placed on top of the basins and
this will be sown to grass, and when
fully improved will present a very
beautiful appearance, as it will be
about five feet above the surrounding
land.
To the Filters.
After leaving the -sedimentation
basins by the route directed, the wa
ter enters a conduit that conveys the
water to the filters.
The filters are of reinforced con-
cret, II feet by(21 feet in size. The wa
ter flows into the filter house through a
reinforced concrete conduit. In front
of each filter is a concrete inlet cham
Der supplied with suitable valves. The
water passes from the conduit to the
inlet chamber into the filters. Each
filter is fitted with cast iron manifold
system set in concrete. Upon this mani
fold system there is ten inches OF prop
erly graded gravel covered with a
screen, and upon this screen there is
thirty inches in depth Of properly pro-
portioned filter sand. The water pass
ed from the inlet chamber on to the
sand, and passes on through the sand
to the gravel on the manifold, or coll
lector system. and passes through cast
iron pipes and the filter controllers
into the clear well.
The clear well IS located directly
below the filters. perfectly protected
from any contamination or dirt, or de-
leterious matter of any kind. The wa
ter is stored in the clear we'll until
necessary for consumption by the city.
The clear well is 81 feet by Gil feet by ~
feet, constructed entirely of reinforced
concrete with cast iron pipe connect
ing the two sections and fitted with
proper battle walls in order to keep the
water in circulation.
Big Capacity.
The normal capacity of the filters
is 100000 gallons every twenty-four
hours, exclusive of the wash water,
and the plant is fully equipped with
four filter units, and it Is provided so
that two more units can be added to
the plant with small additional cost,
and this may be done at any time in
the future.
This plant differs from the slow sand
filter plants in two particulars. First
in the method Of cleaning the sand
bed, second in the use OF the coagulent
in relieving the heavy load that is
carried by the sand in the slow sand
filters.
Cleaning the Filter.
In this plant the sand bed ID clean
ed by both air and water. BY the pros
per manipulation of two valves and
the starting OF the wash water pump,
water may be forced back through and
the manifold system UP through the
sand bed at such a rate as win agitate
the SAND bed and throw up ali the dirt
that has been collected during the pas
sage Of the water. This water flows
into properly constructed cutters, and
thence through the sewers back into