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This study evaluated a non-thermal process for recovering reverse osmosis (RO) concentrate generated from desalting Colorado River water (CRW). Studies sought to determine the mineral precipitation sequence in CRW concentrate as a function of concentration factor (CF) and evaluate chemical precipitation strategies to lower the component ions that drive mineral precipitation. Above CF 10, mineral precipitates included CaSO4, CaCO3, MgSO4, BaSO4, SrSO4, and silica. Lowering pH and adding antiscalant suppressed precipitation below CF 10 but had no effect at higher CF values. Precipitation studies showed that Ca++, Ba++, and Mg++ concentration could be reduced by 96 percent, 94 percent, and 62 percent, respectively. Chemical precipitation also reduced dissolved silica by 94 percent; however, precipitation kinetics were slower. Further concentrating chemically precipitated brine in a secondary RO process showed that up to 80 percent brine recovery (98 percent total recovery) may be feasible. Includes 10 references, tables, figures.

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Edition: Vol. - No. Published: 11/01/2002 Number of Pages: 18File Size: 1 file , 980 KB