Paper B-073

Various molecular tools including real-time PCR, clone library, and automated ribosomal intergenic spacer analysis were used in this column study to analyze the change of microbial composition in response to the addition of various carbon donors and microbial inocula. Whey, emulsified oil and emulsified oil plus surfactant were used as carbon donors. According to the competitive electron accepting processes observed in the columns, four microbial groups were selected as targets in this study: dechlorinating bacteria, iron-reducing bacteria, sulfate reducing bacteria, and methanogens. The combination of the molecular tools developed in this study is proved to be able to effectively detect key microbial groups, and determine and track the microbial composition and its changes during the bioremediation of chlorinated compounds. INTRODUCTION Hill Air Force Base (AFB) is located in northern Utah, approximately 25 miles north of Salt Lake City. Like other Air Force bases throughout the country, past operations and practices for waste disposal have resulted in the contamination of soils and groundwater at the base by chlorinated compounds. Hill AFB is actively seeking innovative technologies to clean up contaminated aquifers and reduce the cost of required remediation efforts across the base. Microbial reductive dechlorination is an important pathway for the biodegradation of chlorinated compounds (Mohn and Tiedje, 1992). Advanced and comprehensive molecular tools would be helpful in examining the diversity and functional ability of microbial communities. The improved understanding of the composition and function of the native and bioaugmented soil community can help improve the efficiency and effectiveness of the remediation of contaminated sites and to optimize the implementation of biostimulation and bioaugmentation strategies. Since 2002, the Utah Water Research Laboratory (UWRL) has conducted a series of laboratory microcosm and column treatability studies to investigate the utility of new molecular biology tools in the evaluation and optimization of TCE remediation strategies (Dupont 2003; Zhou, Dupont et al., 2005). Through column studies, a combination of molecular tools has been developed to easily track and monitor the changes in microbial community composition in columns in response to biostimulation and bioaugmentation, and to evaluate the prevalence of interacting electron accepting processes and genes encoding key enzymes.