Electrobioremediation of soils contaminated with hydrocarbons and metals: Progress report

Restoration of soils contaminated with hydrocarbons and metals is one of the most important problems of environmental protection. During the last 30 years, considerable progress has been made in the development of effective remediation technologies. Modern purging technologies are based on the chemical and biological degradation of contaminants and their conversion to safe forms or to intermediate substances convenient for transport in soils. To accelerate transport of contaminants or their intermediate substances in soils, electrical fields (direct current) are applied to zones being remediated. This allows the volumetric rate of transport to increase approximate to 50-60 times, and the substances to collect at convenient removal sites. Fundamental experiments were performed by a group of researchers at the University of Southern California in the early sixties. The experiments involved application of direct electrical current for acceleration of the flow of solutions in soils. This, together with the latest advances in biodegradation of the eighties and nineties, led to the development of sophisticated multicomponent remediation technologies. Success of these technologies depends on the selection of appropriate combinations of microbiotic and chemicals degradation, and oriented electrokinetic transportation of contaminants to the collection site. A proper combination of remediation techniques is determined by the biological, physical, chemical and geological conditions of the remediated zone. The primary goal of this article is to (1) review recent advances in electrobioremediation technologies and remediation science and (2) evaluate the present state of the problem and the current trends in its development. Another goal is to attract attention of the researchers to the key problems and bottlenecks of the theoretical foundations and mathematical modeling of remediation processes.