(4) Waste water lines provide drainage from the chemical slurry feeder tank
to the wastewater tank and from the erdlator assembly, wet well tank, sludge
concentrator tank, and diatomite filter to two wastewater outlets in the van body. The
waste lines are painted red.
Chemicals for treatment are fed by means of the chemical feed equipment (see
figure 5-7). Two chemical solution tanks at the bottom of the unit supply ferric chloride
and calcium hypochlorite. The chemical slurry feeder, at the top of the unit, contains
two compartments, which supply diatomaceous earth to the fiIter and pulverized
Iimestone to the coagulant (erdlator assembly).
Figure 5-7. Chemical feed equipment.
a. Ferric Chloride and Calcium Hypochlorite. At the beginning of the
operation, the WPU operator prepares a base charge of ferric chloride by mixing a
predetermined quantity of dry ferric chloride with water. The proportion of chemical to
water is prescribed by the appropriate technical manual (TM) for the equipment in use
(1/2 Ib FeCI3 per gal for the 1,500 gph WPU; 1 Ib per gal for the 3,000 gph WPU). The
chemical solution is placed in the lower riqht hand chemical solution tank. A base
charge of calcium hypochlorite is then prepared in the same manner (1/8 Ib per gal for