Direct Current Technologies (DCTs) are remediation techniques for contaminated soil, in which an electrical field is created in the polluted medium by applying a low-voltage direct current across electrodes placed in the ground. This study aimed at evaluating the feasibility of using DCTs for the remediation of different organic contaminants from various types of fine grain soils and sediments. For this purpose, a one-dimensional experimental setup for bench scale testing was assembled and several laboratory tests were performed. The experimental setup included an electrochemical cell, two stainless steel plate electrodes, a stabilized DC generator and tanks for the pore fluid collection. Two types of soils contaminated by diesel fuel and river sediments polluted by polycyclic aromatic hydrocarbons (PAHs) were considered in the investigation. In the experiments, the contaminant removal was evaluated under the influence of the electric current generated by a constant potential difference (0.5-6 V/cm) for a fixed period of time. The results showed that a high efficiency of organic pollutant removal could be achieved via electrochemical methods. About 90% contaminant removal was achieved for PAH-contaminated sediments after a one month treatment, while the diesel fuel contaminated soils resulted in about 45-55% TOC removal and in 70-85% TPH removal. The main factors influencing the process seem to be the process duration and the soil mineralogy, especially the iron content of the treated medium. On the opposite, the applied voltage seems to have a limited influence on the contaminant removal efficiency, good results being achieved with specific voltages as low as 1 V/cm. The results suggest that DCTs can be effectively used for the mineralization of many organics with low energy expenditure, especially in very fine soils, like clays, which are often more difficult to treat with conventional chemical methods, because of their low permeability and high sorption capacity.
Ferrarese, Elisa and Andreottola, Gianni
"Application Of Electrochemical Techniques For The Remediation Of Soils Contaminated With Organic Pollutants,"
Proceedings of the Annual International Conference on Soils, Sediments, Water and Energy:
Vol. 13, Article 26.
Available at: http://scholarworks.umass.edu/soilsproceedings/vol13/iss1/26