Technologies and Costs for Removal of Arsenic From Drinking Water

communities (New Mexico State University, 1979). In one of the studies conducted at Bluewater,New Mexico, EDR brought the level of arsenic in the treated water down to 0.003 mg/L from theinfluent level of 0.021 mg/L. This corresponds to a removal of approximately 86 percent. The feedwater to the EDR unit was drawn from a point before chlorination of the community water supply.The test flow rate was 4.8 gpm, and 80 percent recovery was obtained. Raw water quality for thecommunity water is shown in Table 2-13.TABLE 2-12Influent Water Quality for San Ysidro EDR StudypHParameterConcentration (mg/L)7.1 (units)TDS 810As(total) 0.085Fluoride 2.4Sulfate 36Bicarbonate 552Chloride 142TABLE 2-13Raw Water Quality for Bluewater EDR StudyParameterConcentration (mg/L)pH (units) 7.1TDS 908Na 78Sulfate 398Silica 16Chloride 52In another study, process water from in-situ mining was treated using a 30,000-gpd EDR unit(Garling,1981). The unit removed about 59 percent of the 0.022 mg/L arsenic in the feedwateroperating at a recovery of approximately 81 percent.2-42