Remediation of Silty Clay Soil Contaminated with Metal Ions by Electric Field Technology with the Support of Acidic Injection Wells.

This work aims to propose a new approach for enhancement the reclamation of soil spiked with metal ions, specifically lead and chromium by applying electro-kinetic method. Different tests were carried out on Iraqi silty clay soil that had been polluted with either lead or chromium in concentration of 1500 mg/kg (single system) and in the form of binary system consisted of lead and chromium at concentrations of 750 mg/kg for each metal. The tests have been conducted with 7 days processing time and 1-V/cm voltage gradient. In order to improve the electro-kinetic remediation ability to remove the aforementioned metal ions from Iraqi soil, acetic acid enhanced by two injection wells were applied. Experimental outcomes proved that the lead and chromium can be removed with efficiencies of 18.5 and 12.5%, respectively for tests performed using the distilled water. Utilizing 1-M acetic acid led to an increase in the removal efficiencies to 37 and 21.5%, respectively. However, addition of two injection wells in combination of an acetic acid result in significant increasing in the removal to be ≤ 59%. Finally, the removals of lead and chromium have values of 42 and 28% respectively in the binary system for acetic acid and two injection wells. These values are lower than the efficiencies for same metals in the single system operating in the same conditions, which may be due to metals competing for desorption from the soil. [ABSTRACT FROM AUTHOR]