Lab scale-study on the efficiency and distribution of energy consumption in chromium contaminated aquifer electrokinetic remediation

Abstract

Electrokinetic remediation can effectively remediate chromium contaminated soil, but there are few studies on the remediation of contaminated aquifer. In this paper, a lab-scale electrokinetic remediation experiment of chromium contaminated natural fine sand aquifer was carried out, and the effects of three power supply modes (continuous power supply, intermittent power supply and periodic polarity reversal) on the efficiency and energy consumption were attentioned, and the changes in the electric current, pH and conductivity during the process of the electrokinetic remediation were analyzed. Under continuous power supply and intermittent power supply modes, 96.8%–100.0% and 99.2–100.0% of Cr(VI) pollutants can be removed after 25 h operation. When there were none groundwater flow or none power supply, the remediation effect were not outstanding, which shows that electrokinetic remediation of dynamic aquifers has a promising prospect. Compare with the soil remediation, electrokinetic remediation of the aquifer had a small change of pH in environmental, which was limited to the range of 3 cm close to the anode and 5 cm of the cathode. This paper proposed a method for evaluating the energy consumption of each part of the aquifer during the process of electrokinetic remediation. Due to the massive migration of Cr(VI), the energy consumption near the cathode area accounts for the highest distribution, reaching 30.5–38.5%.