Laserfiche WebLink
<br />resistant feed water pipeline (5,700 feet long and 36 inches in diameter) <br />to the desalting plant. Desalinization would begin with a lime-soda ash <br />pretreatment process to remove calcium and b1carbonate from the feed water <br />to significantly reduce the level of total dissolved solids (TDS). The <br />resulting calcium carbonate sludge would be combined with the reject brine <br />for disposal in the evaporation ponds. From the pretreatment faci11ty the <br />water would flow through a clear well pumping plant to the reverse osmosis <br />desalting unit. The desalted water would be returned to the river through <br />the product water pipeline (2,900 feet long and 30 inches in diameter). <br /> <br />Purgatory Flat Disposal Facilities: The brine and pretreatment sludge <br />v:culd be transported through a 8.95 nlile corrosive resistant brine pipeline <br />(21,860 feet of 12-inch-diameter pipe and 25,380 feet of 10-1nch-diameter <br />pipe) to 612 acres of evaporation ponds at Purgatory Flat (Figure 2). The <br />brine mixture would pass through one of the three settling ponds (each <br />250 X 525 feet by 6 to 9 feet deep) where the sludge, primarily calcium <br />carbonate, would settle out of the brine by gravity. The sludge would be <br />removed from the settling ponds and buried in PVC-lined disposal cells (86 <br />cells of at least 12,650 cubic yards capacity each). <br /> <br />From the settling ponds, the brine would be transferred to evaporation <br />ponds for the three stage evaporation process. As the salinity of the <br />brine increases it would be transferred from Stage I ponds (298 acres, 7 <br />feet deep) to Stage II ponds (166 acres, 7 feet deep), and then to Stage <br />III pondS (148 acres, 20 feet deep) for precipitation of salts and final <br />storage. <br /> <br />The facilities for the three desalinization alternatives are identical with <br />the exception of the material used to line the settling and evaporation <br />ponds. The pond linings vary by alternative. <br /> <br />Alternative 1 - PVC 11ning. The settlin~ ponds would n~ve a <br />20-~li 1 P\'C 1 iner laid over smoothly graded earth and covered by 1 foot of <br />soil cement. The evaporation ponds would be lined with 20~mil PVC lining <br />covered by 10 inches of earth. Approximately 3,000,000 ydl of liner would <br />be needed. This alternat1ve is the original project described in the 1981 <br />Conclud1ng Report. Costs have been indexed to 1983 levels for comparison <br />purposes. <br /> <br />Alternative 2 - CPE Lininc. The settling and evaporation ponds <br />wc~ld have a 40-mil reinfurced, chlorinateo-polyethylen~ (CPE) liner laio <br />ever 6 incheS of sub~racc material anc protecteo,Dj 6 inchES of cover <br />["aterial (Figure 3). Approximately 3,000,000 yd" of linet' ~'culd be needed. <br /> <br />Alternative 3 - Clay Lin1n~. The settling ano evaporation ponds <br />would have a 2-foot-thick clay lining laid over 6 inches of subgrade <br />material and protected by ~ inches of cover material (Figure 4). <br />Approximately 2,500,000 yd of clay would be needeC. <br /> <br />B. TOTAL EVAPORATION ALTERNATIVES (~ithout Quail Creek Project Upper <br />Diversion Structure) (Alternatives 4-5) <br /> <br />5 <br /> <br />0026'.4 <br />