USE OF A MATHEMATICAL-MODEL FOR PREDICTION OF OPTIMUM FEEDING STRATEGIES FOR INSITU BIOREMEDIATION

Liquid wastes containing radioactive, hazardous, and regulated chemica ls have been generated throughout the 40+ years of operations at the U S Department of Energy (DOE) Hanford site. Some of these wastes were d ischarged to the soil column, and many of the waste components, includ ing nitrate, carbon tetrachloride (CCl4), and several radionuclides, h ave been detected in the Hanford ground water. Current DOE policy proh ibits the disposal of the contaminated liquids directly to the environ ment, and remediation of the existing contaminated ground waters may b e required. In situ bioremediation is one technology currently being d eveloped at the Hanford to meet the need for cost-effective technologi es to clean ground water contaminated with CCl4, nitrate, and other or ganic and inorganic contaminants. This article focuses on the latest r esults of an ongoing effort to develop effective in situ remediation s trategies through the use of predictive simulations. In particular, st rategies for nutrient injection are developed that minimize biomass ac cumulation within the flow field and thus extend the life of injection wells.