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AN INVESTIGATION OF ARSENIC MOBILITY FROM IRON OXIDE SOLIDS PRODUCED DURING DRINKING WATER TREATMENT
Parks, A N., P A. Gallagher, C A. Schwegel, A H. Ackerman, AND J T. Creed. AN INVESTIGATION OF ARSENIC MOBILITY FROM IRON OXIDE SOLIDS PRODUCED DURING DRINKING WATER TREATMENT. Presented at 2003 Pittsburgh Conference, Orlando, FL, March 9-14, 2003.
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 regulations. One of the treatment options is iron co-precipitation. This treatment is attractive because arsenic and iron are geologically correlated so that well waters containing arsenic have a propensity to contain iron. Iron can be precipitated from water via aeration and in the process the iron co-precipitates some of the arsenic leading to arsenic removal. The aeration can take place during the treatment process or occur as the water is pumped from the supply through the distribution system. The presence of these iron oxide solids can alter the distribution of the naturally occurring As(III) and As(V) in the water. The stability of the resulting iron oxide/arsenic complex ("FeOOHAs") is not well characterized. This research will attempt to estimate the distribution of As(III) and As(V) on these iron oxide solids and estimate the stability of these complexes produced by changing water quality parameter. The arsenic distribution on the solids will be estimated by extraction with acetic acid followed by IC-ICP-MS separation and detection. The stability will be estimated by conducting total metal measurements on solids in contact with waters prior to and after changes in pH, nitrate and chlorine concentrations