Abstract

Bioremediation seeks to use biological processes to restore contaminated environments to productive use. Many contaminants at industrial, agricultural, and accident sites are amenable to bioremediation. Most organic contaminants are biodegradable under some conditions, and optimizing this biodegradation is the principal thrust of bioremediation to date. Widely used treatments for hydrocarbons include the addition of oxygen or alternative electron acceptors, and the provision of limiting nutrients such as nitrogen and phosphorus. More recalcitrant organic contaminants, such as some halogenated products and some pesticides, herbicides and explosives, require more sophisticated approaches. These have included the addition of co-substrates to stimulate the growth of degrading organisms, various treatments to increase the bioavailability of the contaminants, and sequential anaerobic and aerobic degradation. Inorganic contaminants are also amenable to bioremediation, since they may be sequestered or extracted from soils and waters by microbes and plants. Bioremediation competes in the marketplace with a range of chemical and physical treatments for cleaning contaminated sites and waters; in general bioremediation is among the least expensive and most benign, but also one of the slowest options.