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Recent regulations have lowered the acceptable total arsenic level in drinking water to 10 Au/L.The arsenic levels in the two groundwater wells operated by the Walker River Paiute Tribe havebeen measured to range between 70 and 110 Au/L. A treatment technology is needed that canconsistently reduce these levels to below regulatory limits. In addition to arsenic, significantlevels of silica (54 mg/L) and an "elevated" pH (8.6) are present that must be addressed whenselecting the appropriate treatment technology.The raw water quality can influence the effectiveness of the treatment options evaluated. Therange of selected raw water quality parameters encountered during the study are presented in the paper.The ranges experienced were not considered unusual, as the Tribe generally drawsalternately from two well sources for varying times. The arsenic was speciated on-site andsubsequently determined to be all in the Assup+5/sup state.Seven technologies were evaluated through either bench- or pilot-scale testing for their ability toconsistently remove arsenic. The technologies included coagulation/microfiltration (C/MF),coagulation with conventional direct filtration, coagulation with high-rate direct filtration,granular ferric hydroxide (GFH), iron doped activated alumina (AA FS-50), iron doped naturalzeolite (Z-33), and ion exchange. The results of the study indicated that each technology wascapable of removing arsenic from the Tribe's water. However, not every technology couldconsistently remove arsenic below the MCL or run for acceptable operation times. Includes tables, figures.

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Edition: Vol. - No. Published: 11/02/2003 Number of Pages: 5 File Size: 1 file , 260 KB