AWWA WQTC71473

This study examined the effects of pH, orthophosphate and blending ratio (four levels: 0%, 20%, 80% and 100% desalinated water) on copper and lead release in surface water treated at Graham Hill water treatment plant and its blends with desalinated water treated at the Santa Cruz SWRO Pilot Plant. Both copper and lead data showed that the presence of 0.5 mg/L phosphate was accompanied by a substantial decrease of metal release at all pHs. Increase of phosphate from 0.5 to 1.0 mg/L caused relatively minor further reductions in copper and lead concentrations. In the absence of phosphate, copper release increased as blending ratios increased from 0 to 80% of desalinated water. However, in 100% desalinated water release was less than in non-blended Graham Hill water or any of its blends. Includes 5 references, table, figures.