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ARSENIC MOBILITY FROM IRON OXIDE SOLIDS PRODUCED DURING WATER TREATMENT
Whiting, J., P A. Gallagher, C A. Schwegel, AND J T. Creed. ARSENIC MOBILITY FROM IRON OXIDE SOLIDS PRODUCED DURING WATER TREATMENT. Presented at Remediation of Chlorinated and Recalcitrant Compounds: The Fourth International Conference, Monterey, CA, May 24-27, 2004.
To assess the stability of "FeOOHAs" residues in existing drinking water distribution systems and drinking water generated wastes.
The Arsenic Rule under the Safe Drinking Water Act will require certain drinking water suppliers to add to or modify their existing treatment in order to comply with the new 10 ppb arsenic standard. One of the treatment options is co-precipitation of arsenic with iron. This treatment is attractive because arsenic and iron are geologically correlated so that well waters containing arsenic have a propensity to contain iron. Specifically, iron can be precipitated from water as iron oxide (AFeAsOOH@) via aeration and in the process co-precipitate some of the arsenic leading to arsenic removal. In addition, adsorptive media can be used to remove arsenic from the drinking water supplies. In either case arsenic containing solids are generated and these solids can be discharged to the local wastewater treatment plant, deposited in landfills, or discharged to the local waterway.
The distribution of As(III) and As(V) on these solids may aid in estimating the mobility of the arsenic when these solids are exposed to different environmental factors. The research presented will attempt to estimate the distribution of As(III) and As(V) on these treatment solids using an acetic acid / EDTA extraction solvent. Desorption experiments will be conducted to evaluate the species specific mobility of the leachable arsenic. The ultimate goal of the research is to produce an improved understanding of the environmental factors which may affect the mobility of the arsenic.