Evaluation of a Groundwater Arsenic Treatment Process in Response to Organic Matter Inclusion in Feed Water

Abstract

The contamination of groundwater by sediment-derived arsenic threatens the health of millions of people worldwide and a large number of drinking water treatment units have been employed to prevent this toxicity. This study aims at evaluating the influence of organic matter on groundwater arsenic treatment practice and proposing the modifications related to this issue. The arsenic removal efficiency was found to be decreased even in the presence of a low concentration of organic matter, 5 mg/L as TOC (total organic carbon), and gradually deteriorated with higher concentrations. Nevertheless, a high concentration of bioleached arsenic, above 130 μg/L, was noticed in the inoperative condition of the treatment unit. A simple modification in the treatment process, using an additional iron-matrix layer, substantially increased, 12% more, the arsenic removal efficiency even in the presence of high concentration of organic matter. Strategies were proposed to combat the bioleaching of arsenic in the treatment process. This study revealed that organic matter would significantly impede the arsenic removal process for drinking water and hence safe remediation strategies were imperative.