Strategies for the sustainable practice of electrokinetic technology: The case of mixed contaminants in a clayey soil

Abstract

Electrokinetic (EK) remediation is a developing technology for treating a wide range of organic and inorganic contaminants from soil. One aspect of a sustainable remediation is to be economically viable. Various strategies have been used for evaluating the energy consumption and costs in the EK process. This study investigated the effect of voltage gradient (1.0 and 2.0 V cm −1 ), pH controlling, and duration time (7 and 15 days) on contaminants distribution and energy consumption during EK. An alkaline clayey soil was artificially contaminated with lead, zinc, nickel, and phenanthrene. Increasing voltage and controlling pH was ineffective on the mobility of mixed contaminants as they increased soil resistivity. Controlling pH accounted for 70% of the increasing total energy consumption (1521.65 kWh m −3 ) and failed to mitigate soil contamination. Brij 35 worked better than Tween 80 in the transportation of the target contaminants in the clayey soil. By Brij 35, 32% of total contaminants were removed from the studied soil with an optimal energy consumption of 892.8 kWh m −3 . The strategies of increasing voltage gradient and pH control are not recommended for EK remediation of alkaline clayey soils. • pH control was not a sustainable strategy in EK remediation of mixed contaminants. • The soil electric resistance increased with time and impeded contaminant mobility. • Increasing voltage was unsatisfactory and costly for clayey alkaline soil.