Managed aquifer recharge using reclaimed water is one viable method for supplementing our depleted freshwater resources. Unfortunately, during this process, injected reclaimed water can mobilize arsenic from arsenic-containing minerals in aquifer formations. To help bolster our understanding of the mechanism of arsenic mobilization and the lifecycle of arsenic during MAR, arsenic mobilization and secondary mineral precipitation during arsenopyrite oxidation was investigated in model reclaimed water (i.e., 10 mM sodium nitrate or chloride). Concentrations of Fe(III), comparable to those found in reclaimed water, were also added to these systems. We found that in the presence of Fe(III), there were higher aqueous arsenic concentrations for both the chloride and nitrate systems. The addition of Fe(III) also lead to faster phase transformation for iron oxide secondary mineral precipitates. These findings have important implications for establishing safe and sustainable MAR operations that minimize arsenic mobilization.

Fe(III) affects arsenic mobilization and secondary mineral precipitate phase, morphology, and coverage during arsenopyrite oxidation

249th National Meeting (2015)

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