Optimizing parameters for the remediation of chromium(VI) contaminated groundwater on Tamil Nadu Chromates and Chemicals Limited (TCCL) site of Ranipet, Tamilnadu using electrocoagulation process

Abstract

This paper presents the effects of variables such as electrode material, electrode distance, pH, initial concentration of Cr(VI), applied current, electrolyte and time duration in the treatment of contaminated groundwater for the removal of Cr(VI) at two different concentrations of 200 and 800 mg/L of Cr(VI) using batch electrocoagulation process. Initially, the conditions were optimized from synthetic contaminated water, which was in congruence with chloride and sulphate ions as present in the contaminated groundwater. The optimum conditions obtained on removal of Cr(VI) from synthetic contaminated water were applied in real Cr(VI) contaminated groundwater collected from a bore well at chromate ore processing residue (COPR) dumpsite. The results of the treated contaminated groundwater were found that all the parameters were within the limits of Pollution Control Board discharge standards. The efficiency and energy consumption on the removal of Cr(VI) from real contaminated groundwater were compared with and without addition of NaCl. The results suggest that the optimum conditions for a 99.99% removal efficiency were initial concentration 200 mg/L of Cr(VI), pH 6.0, applied current 2 A, electrolyte 2 g/L of NaCl, time duration 35 min and energy consumption 2.625 Whr/m3