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...,..",~-"... \. . Ion exchange softening technology should be tested on a demonstra- tion plant scale If sIte-specific power plant design criteria and water supply qualIty show an economic advantage. The test ro ram would be enhanced by Involvement of Ion exchange resIn manu~aciurers and Ion exchange equIpment supplIers. Sidestream lime/soda softening technologIes should be demonstrated on cooling systems using hIgh salinIty makeup waters to develop ac- curate technIcal and economic data. w CJ1 N 00 cooling system materials Based on these conclusions, the fOllow]"9 " recommendatIons are made: Appraisal-level cost estImates, at an accuracy of plus or minus 25%, were developed for capital, chemIcal usage, operatIng and maintenance labor and materials and power cost. Levellzed cost comparisons for the five process op- tions were developed using microcomputer spreadsheet models and economIc fac- tors provided by Southern CalifornIa Edison Company. The results of the economIc analyses are summarized as fol lows; Cost Comparison of Process OptIons (Level Ized Oost In i1000) Option II II] ]V V Capltlll 6247 5369 2.5}69 7901 799B ChemIcals }006 2397 70] 56] 2780 LlIbor & Repair 1436 120 2162 1066 140} Power 3153 2032 302 5202 398B Totol 13842 11011 28534 uno 16169 These comporetlve costs show thot OptIon I I (sldestream softening) Is lowest In toto I levellzed cost, followed by OptIon I (Ion exchange softening>. which Is approxImately 26% hIgher. An economIc sensItivIty analysis was performed to examine the effect on vary- Ing capital cost, chemical cost, O&M labor and materIals cost and power cost from 7.5~ to l.5OS of the base case costs. The sensitivity analysIs showed that only chemical cost changed the relative rankIng of the optIons. Option I slips to third place If chemical costs reech l.5OS of the base case, illustrat- Ing the Impact of high chemical usage for sldestream slllcll control. The overall results of the Task 3 study produced the following conclusIons: . Sldestream lime/soda softening W8S the most cost-effectIve process option for treating Palo Verde IrrigatIon Outfal I Drain water quality. . Ion exchange softening technology, using coolIng tower blowdown for regeneration, appears to be technically viable based on short-term testIng. end Is likely to be competitive In cost for waters which ere high In hardness, high In sodium and low In sll lea. . Wastewater evaporators ere more cost-effective than evaporetlon ponds for disposal of recycleble wastewaters, end provide the eddl- tlonel benefIt of a high quality water supply for ful I or partIal mekeup for other plant systems IncludIng condensate end flue gas desulfurlzetlon. Conceptual-level cost estimates for the use of west. heat steem 8S an alternative to electric-driven vapor c~ pressors for wastewater evaporators showed signifIcant cost savIngs potentIal, provided the Issues of In-plant steam supply system design end availability are fully determined. . Both Ion exchange and' lme/sodo softening technologies al low opeie- tlon of the powerplant cIrculating water system at high cycles of concentratIon, which can produce a highly corrosIve envIronment for v; . . Waste heat evaporators for concentration and reuse at powerplanf wastewaters should be evaluated on a design-level basis In suffI- cient detail to develop accurate cost comparisons with vapor c~ pression evaporator technology. Powerplant cooling water system materials of construction should be evaluated for applIcation In hIgh chloride and hIgh totel dissolved solids operating envIronments to account for plant operatIon on sel Ine water sources at hIgh cycles of cooling tower concentratIon. . v;;