Electrochemical Remediation of Oil-Contaminated Soils Factoring in Terrain: Theoretical and Experimental Studies

Environmental problems associated with soil contamination by oil products have become more and more acute over the years. They require effective and rational technical and economic solutions. The electrochemical method is one of the solutions for remediating oil-contaminated soils. Experimental and theoretical studies made it possible to develop the physicochemical and technological foundations of a new resource-saving and energy-efficient electrochemical process for cleaning soils from oil, oil products, and highly mineralized waters in situ without labor-intensive and expensive excavation operations or the use of special chemical reagents. It was theoretically and experimentally confirmed that there is a decrease in contaminant concentrations after soils of different types are treated with small direct currents taking terrain into account. The trend revealed allowed us to propose electrode arrangements to ensure that soils are evenly treated by creating a nearly homogeneous electric field. The arrangements factor is uneven contamination of the territory being treated and its relief. Based on such arrangements, installations for effective soil remediation with reduced energy consumption were developed for the implementation of the electrochemical method. For various modifications of these installations selected depending on pollution and terrain, the use of a single electric power source is possible. In areas with depressions, monocathode (cathodocentric) circuits can be used, where one cathode is located in the center and anodes are located along the perimeter. Methods for calculating the key technical, energy, and economic parameters of electrochemical remediation are proposed. They include current and voltage, the parameters and number of electrodes in the arrangement, properties of the soil mass being cleaned, features of the distribution of the pollutants over the territory, and the required degree of remediation.