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'::':. , en ":1' ,. '<.'j'l " "", C\1 0 " 0 ~~ . ~/ ,:" 1 ",', " " .;.<, }; ,': ~ ~ ~ " evaporators are used for water recovery from recyclable wastewaters. Evapora- tion ponds are used for disposal of non-recyclable wastewaters and softener sludges. The high quality product water from the wastewater evaporators is used as condensate makeup. There is no commerical appl ication similar to this process option. The in- dividual components, however, do have operating history at electric util ity plants. Since sidestream softening permits a major increase in cooling tower cycles of concentration, the blowdown available to supply the scrubber and ash systems Is greatly reduced. Although cycles could be reduced to increase available blowdown makeup to these systems, the incentive for providing the treatment initially is lost. Under this process option, the estimated chloride concentration in the scrub- ber system, without loading from the hydrogen chloride gas in the flue gas, would exceed 28,000 mg/I. The cost penalty for materials of construction in the scrubber to operate with this makeup would be substantial. For these reasons, this process option was dropped from further consideration. Lime/Soda Sidestream Softenlng/VCE/Evaporatlon Ponds In this configuration, raw water is used for cool ing tower makeup with sldestream lime/soda softening appl led to the circulating water to reduce hardness, sil ica and phosphate concentrations. Vapor compression evaporators are used for concentration of recyclable wastewaters, and evaporation ponds are used for disposal of non-recyclable wastewaters and sludges. High quality water from the vapor compression evaporators suppl ies condensate system makeup requirements with the excess blended with raw water to supply the scrubber and ash systems. Evaporation Ponds In this process option, no makeup or sldestream treatment of the circulating water Is used, which results in a circulating water concentration factor sig- nificantly less than the other options. AI I wastewaters and sludges are dis- charged to evaporation ponds. The use of evaporation ponds only is the least complex option, but Is also very expensive because of the large volume of wastewater requiring disposal. This scheme also provides no means of recovering water for station reuse. Since the estimated disposal acreage requirements resulted in economically prohibitive estimated costs, this option was dropped from further considera- tion. VCE/Evaporatlon Ponds In this configuration, no raw water treatment or sidestream treatment of the cooling water system are employed. Recyclable wastewaters are processed in vapor compression evaporators with the high qual ity water from the evaporators used as makeup to the condensate, circulating water, ash and scrubber systems 4-11