The problem facing the nations for the cleanup of hazardous waste sites are significantly greater than that anticipated two decades ago. The use and manipulation of microorganisms for treatment of municipal wastewater has been applied since ancient times. The use of microbes to degrade waste is as old as nature, and man has used bioremdiation techniques for decades to degrade municipal wastewater, refinary waste, and specific chemial process waste streams. In the last decade significant advances have
been made in aquiring knowlege about microbial metabolism of xenobiotic compounds.. Bioremcdiation is the process of removing or reducing the mobility and or toxicity of contaminants of concern at a site. Bioremediation is a managed, demonstrated active treatment process that uses micro organinSIT1S to degrade and transform organic chemicals in contaminated soil, sludges, and resid ues. Groundwater con tamina tion may be reduced or completely eleminated by this technology. Bioremediation is becoming a popular approach in the cleanup of petroleum hydrocarbons, because it is simple to maintain, applicable to a large area, cost - effective, and most importantly, it leads to the complete dsetruction of the contaminant. Microbial degradation of hydrocarbons results in the release of innocuous products such as carbon dioxide, water, and cellular biomass as the final products. Bioremediation processes have resulted from the application of knowledge from microbiolgy, biochemistry, environmen tal engineering and chemical engineering. Bioremediation however, is not the answere to all contamination problems. Its applicability must be determined at each site which would be dependent on the local site microbology, hydrology, geology and chemistry.
In this aricle other means of treating the contaminated sites are listed and compared with bioremediation. Finally, two case studies
regarding Exxon Valdez oil spill and Persian Gulf spill are discussed.