Electrokinetic Remediation Procedure Applied to Polluted Soils in Southern Spain

Abstract

Electrokinetic remediation (EKR) is probably the only feasible alternative to treat contaminated soils with low hydraulic conductivity. This technology is based on the application of an electric current between two groups of electrodes into the soil inducing several transport and transformation processes. As a result, the contaminants and water are transported toward the electrodes by electromigration, electroosmosis, electrophoresis, and diffusion. This study applied EKR to a real soil with a high concentration of lead. To evaluate the most suitable reagent to enhance the technique, semibatch extraction and EKR experiments at different scales were carried out. The enhancing agents used were acetic and nitric acids as weak and strong acids, respectively, and EDTA as a complexing reagent. A mathematical model for the comparison of the energy requirements at different scales was applied, showing that the defined parameter is a useful tool for the prediction of the energy requirements of EKR technique. The results indicate that the proposed methodology allows better knowledge about the behavior of contaminants under different experimental conditions.