AWWA MTC95025

The Capistrano Beach Water District (CBWD), located in Southern California, serves about 21,000 customers. Presently, CBWD depends 100 percent on imported water supply through the member agencies of the Metropolitan Water District of Southern California. The current water demand of CBWD is approximately 3,500 acre-fee per year (AFY). CBWD is seeking an additional water supply to supplement its water supply and to decrease its dependence on imported water. The southern part of the San Juan Basin underlies most of the service area of CBWD. The groundwater in this area is characterized by high total dissolved solids (TDS) content, and high levels of iron and manganese. Without treatment, the groundwater cannot be used as potable supply. This paper examines two membrane processes, electrodialysis reversal (EDR) and reverse osmosis (RO), and alternative pretreatment schemes, for treating the brackish groundwater for potable uses.