TM 5-4610-218-12
b. Water Treatment Process. The water treat-
2-7. Water Purification Process.
ment process reduces the organic and suspended
a. Chemical Requirements. The following
matter of raw water to a minimum and produces
chemicals are required in the treatment and fil-
water suitable for application to the diatomite fil-
tration processes.
ter.
(1) Ferric chloride as a coagulant.
(1) Erdlator tank.
(2) Calcium hypochlorite as a disinfectant.
(a) Raw water is pumped from its source by
the raw water pump through the aspirators (fig. 1-
4) to the influent launders from where it overflows
(4) Diatomaceous earth as a filter aid.
into the downcomer tube, or mixing zone.
(5) Activated carbon as an absorber to control
(b) The aspirators aerate the water which
objectional tastes and odors. The chemicals are
improves the sludge formation.
mixed proportionally with water in accordance with
an established base charge. The base charge is the
(c) The flow of water to the influent laun-
concentration of mixture or solution expressed as
der is regulated by valve CV-9 (fig. 2-1).
the amount of chemical in a measured quantity of
water prepared for. the chemical feeder.
Figure 2-1. Preliminary positioning of valves.
2-25
