Abstract |
Bioremediation is defined in the article as the process by which microorganisms are stimulated to rapidly degrade hazardous organic contaminants to environmentally safe levels in soils, subsurface materials, water, sludges, and residues. Stimulation is achieved by the addition of nutrients and a terminal electron acceptor, usually oxygen, because most biological reactions occur faster under aerobic than anaerobic conditions. Under anaerobic conditions, nitrate has been used as the terminal electron acceptor. The microorganisms use the contaminants as a food source and convert the contaminants into biomass and harmless by-products of metabolism such as CO2 and inorganic salts. Usually bioremediation is used to degrade contaminants that are sorbed to surfaces or dissolved in water rather than to degrade pure chemical(s). As a result, the process is used in conjunction with other techniques in remediation of contaminated sites. The contaminants can be biodegraded in situ or removed and placed in a bioreactor, which can be placed off or at the site where the contamination occurred. (Copyright (c) 1992 by Academic Press, Inc.) |