Removal of arsenic and COD from industrial wastewaters by electrocoagulation

Abstract

The paper deals with the treatment of arsenic-containing industrial wastewaters by electrocoagulation. The waste issued from a paper mill industry downstream of the biological treatment by activated sludge was enriched with arsenic salts for the purpose of investigation of the treatment of mixed pollution. First, the treatment of single polluted waters, i.e. containing either the regular organic charge from the industrial waste or arsenic salts only, was studied. In the case of arsenic-containing waters, a broad selection of experimental data available in the literature was compiled and interpreted using an adsorption model developed previously. The same technique was used in the case of industrial waste. Arsenic-enriched paper mill wastewaters with various amounts of As salts were then treated by electrocoagulation with Fe electrodes. The set of data obtained were interpreted by a model developed on the basis of the separate models. The agreement between predicted and experimental variations of the As concentrations ranging from 0.3 µg/L to 730 µg/L showed that both the organic matter and As salt can be removed from the liquid independently from each other.

Keywords

• Electrocoagulation
• industrial wastewaters
• arsenic
• adsorption model