CAUTION: If air is sucked into the strainer, the capacity of the pump wiII be reduced
and floc floatation in the erdlator tank wiII result. Dirt, sand, or other foreign
matter wiII damage the equipment, resulting in loss of production and costly
(5) The collapsible water storage tanks (see figure 5-5, circle F) should be
located on the filter effluent side of the unit as near to the WPU as possible. They
should be placed on firm, level ground or on a raised platform. The surface of the
foundation should be covered with a ground cloth to protect the bottoms of the tanks
from miIdew, mold, or damage. Both tanks should be the same level so that water wiII
flow from one to the other by gravity.
(6) Under normal operating conditions, the distribution pump (see figure 5-5,
circle G) and the raw water pump wiII be identical, electrically driven pumps. When two
pumps are required to supply raw water, a gasoline engine driven pump is used for
(7). The two wastewater Iines (see figure 5-5, circle H) divert the wastes
from the purification process to a suitable wastewater disposal area. In the continental
United States, this may be a problem area since the wastes from the WPU are chemical
wastes and must be disposed of according to Federal, state, and local environmental
pollution guidelines. The unit sanitary engineer or environmental science officer should
be consulted in the event that a question arises in this area.
PRODUCTION OF POTABLE WATER USING THE ERDLATOR
a. Chemical Requirements. The following chemicals are required in the
treatment and fiItration process:
Ferric chloride (FeCI3) as a coagulant.
Calcium hypochlorite (Ca(OCI) 2) as a disinfectant.
Pulverized limestone (calcium carbonate--CaCO3) as a coagulant aid.
Diatomaceous earth as a fiIter aid.
Activated carbon as an absorber to control objectionable tastes and
The chemicals are mixed proportionally with water in accordance with an established
base charge. The base charge is the concentration of mixture or solution expressed as
the amount of chemical in a measured quantity of water prepared for the chemical