Feasibility Study of the Electrokinetic Remediation of a Mercury-Polluted Soil

This chapter is focused on the study of electroremediation of heavy metals from a real soil. Specifically, the case of the study was a soil from Almaden mining district, with a very high mercury concentration. The risk assessment of heavy metals depends on the mobility and bioavailability and not only on the total concentration. Therefore, this study evaluates the distribution of mercury into different fractions before and after the electrokinetic treatment. The electrokinetic experiments were performed in two operating scales that differ in more than two orders of magnitude. The results for both scales are consistent with the predictions of simple models, so it can be assumed that they are useful for the evaluation of a full-scale implementation. Two enhancing agents were studied in the application of electrokinetic process according to the mercury distribution in BCR fractions (Community Bureau of Reference). First, iodide was applied as complexing agent, and it was found that after treatment the most mobile fraction of mercury increased. Thus, to remove this mobile mercury fraction, electroremediation experiments were done with nitric acid as enhancing agent. (Less)