A number of U.S. Army sites are contaminated with recalcitrant chemicals such as trichloroethylene (TCE), perchloroethylene (PCE), vinyl chloride, and various explosives (i.e., TNT). Bioremediation is the use of microorganisms to eliminate or reduce the concentrations of hazardous materials from air, water, or soil. Over the past 20 years, this technique has been utilized in the successful cleanup of thousands of contaminated sites with more labile chemicals such as petroleum hydrocarbons, non-chlorinated solvents, and soluble organic wastes. However, very little research has been conducted on the contributions of individual species in the complex and unique roles involved in the degradation of the above-referenced recalcitrant compounds. EnSolve has developed a patented fixed-film bioreactor that is successful in reducing high concentrations of labile organic chemicals such as those mentioned earlier. It has not yet been employed in the degradation of recalcitrant molecules. EnSolve proposes to develop a TCE-degrading biofilm using a unique co-substrate "pulsing" technique. Attempts will be made to develop biofilms composed of bacteria only, fungus only, and mixed cultures (i.e., both bacteria and fungus). TCE degradation rates and electron microscopic techniques will be utilized to follow the growth and development of each biofilm type. A fixed-film system that could degrade recalcitrant molecules would have tremendous benefits to the DOD, DOE, and private industry. In addition to being more environmentally friendly, the successful biotreatment system would save customers money by minimizing excavation, digging and hauling of hazardous wastes to landfills or incinerators. Such a system could be employed on over 3,000 DOD and DOE sites within the next 10 years thereby generating high paying employment opportunities for over 400 people.
