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Many of the City of San Diego's groundwater sources require desalination, due tohigh salinity, before it can be used to supplement drinking water supply. One of theCity's potential groundwater desalination projects is located in an inland area, wherereverse osmosis (RO) concentrate disposal options are limited. This location, on the SanPasqual Basin, also has high levels of silica that limit RO process recovery to 65-75%.In order to increase the overall recovery of the desalination process, two innovativetechnologies were tested in this study. A Vibratory Shear Enhanced Process (VSEP) anda Bipolar Membrane Electrodialysis (BMED) system were used for RO brineminimization and beneficial reuse, respectively. Studies with VSEP were performed atthe pilot scale. The VSEP system was tested with a range of flux (30-65 gfd) andrecovery (50-75 %). After pretreatment (acid and antiscalant) of RO concentrate, anoverall feed water recovery of more than 93 % was achieved by using VSEP for treatingprimary RO concentrate. The product water quality from the VSEP was similar to theprimary RO. On average, two chemical cleanings/week were necessary for the VSEP. Forbeneficial reuse, a bench-scale BMED system was used to generate acid and base fromRO concentrate. The BMED process was tested as a proof of concept technology fortreating RO brine. Dissociation of salt was accomplished by using a DC voltage betweentwo electrodes. BMED was effective in treating RO concentrate and producing acid andbase for beneficial reuse. Mixed acids and bases with concentrations up to 0.2 N wereproduced using BMED for treating RO concentrate. Includes 11 references, tables, figures.

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Edition: Vol. - No. Published: 11/01/2009 Number of Pages: 16File Size: 1 file , 1.2 MB