Recent advances in the bioremediation of arsenic-contaminated groundwaters

The application of biological processes for the oxidation and removal of dissolved iron was found to be an efficient treatment technique for the simultaneous removal of arsenic, from initial concentrations between 60 and 80 μg/l to residual (effluent) arsenic concentrations lower than the limit of 10 μg/l. The paper was focused on the removal of As(III) as the most common species in anaerobic groundwaters and generally is removed less efficiently than the oxidized form of As(V). To obtain information for the mechanism of As(III) removal, X-ray photoelectron spectroscopy (XPS) analyses were applied and it was found that As(III) was partially oxidized to As(V), which enabled the high arsenic removal efficiency over a treatment period of 10 months.