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...... If? ~ N e, C',' The plant wastewaters are collected in a 7.5 mil I Ion gallon surge pond for processing by vapor compression evaporators. The total inflow of 730 gpm 15, fed to two 500 gpm and one 250 gpm concentrator units operating In parallel. The brine concentrator product rate is 650 gpm with 80 gpm of waste brine produced. The distil late supplies makeup to the condensate system with the excess available for blending with the raw water to the ash and scrubber sys- tems. The ash and scrubber system makeup requirements are satisifled by a blend of residual concentrator product and the Lower Virgin River water. Acid addition may be necessary to control the bicarbonate In the ash system makeup. The chloride contribution of the makeup water to the FGD circulating chloride con- centration should be less than 3,500 mg/I. Non-recyclable wastewater Including sldestream softener sludge and brine concentrator waste are disposed of In 133 acres of evaporation ponds. Option I I I-I V - Makeup Llme/~oda Softenlng/VCE/Evaporatlon Ponds The process flow diagram for Option II I is presented In Figure 4-3 and the process flow and material balance are found In Appendix C. The Lower Virgin water 15 processed by two 9,000 gpm softener/clarifiers operating In parallel. The effluent 15 control led at 50 mg/I calcium, 0.2 mg/I phosphate and 12 mg/I of silica through the addition of 85% lime and 98% soda ash. The effluent is collected in a 5.5 million gallon collection basin for distribution to the station. Sulfuric acid, chlorine and scale Inhibitor are added to the softened water for scale and microbiological control In the circulating water system. The cooling towers are operated at limits of 600 mg/I calcium and 150 mg/I silica. The resulting blowdown of 591 gpm 15 collected with other miscel- laneous wastewaters In a 10 mill Ion gallon surge pond for processing In the concentrators. The total wastewater Inflow of 1020 gpm to the surge pond Is processed by four 425 gpm VCE's operating in parallel. The product production of 966 gpm sup- plies the makeup needs of the condensate system with the excess blended with softened water to supply the ash and FGD systems. The brine waste flow of 54 gpm 15 discharged to the evaporation ponds. The ash and scrubber system makeup requirements are satlslfled by a blend of residual concentrator product and softened Lower Virgin 'River water. The waste brine and softener sludge wastes are disposed of In 64 acres of evaporation ponds. Opt Ion I V-SE - Makeup I Ime/~oda Soften I ng/VCE/Evaporat Ion Pond~ Option IV Is the same configuration as Option I II except that secondary ef- fluent is the station's water source. The process flow diagram is presented In Figure 4-4 and process flow and material balance is found In Appendix C. 4-16 1 ! ,.'