Modeling and economic analysis of in situ remediation of Cr(VI)-contaminated soil by electromigration

In order to estimate the economics of remediation of metal-contaminated soil by electromigration, a conceptual model of a site and preliminary engineering approaches were proposed. Electrode designs and a water-treatment scheme were proposed for a 30 m x 30 m x 2 m bed of chromate-contaminated soil. A mathematical model was developed and used to estimate remediation times and power consumption as functions of several variables including number of electrodes, chromate concentration, and applied voltage. The model assumed a constant typical soil resistivity and no adsorption of the chromate ions. The system design and outputs from the model were then used to estimate the capital, installation, and operating costs of purging the soil of the hexavalent chromium. The total remediation cost for a 30 m by 30 m by 2 m volume of soil contaminated with 100 mu g/mL Cr(VI) in the groundwater was in the range of $130/ton.