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BENCH-SCALE PERFORMANCE OF PARTITIONING ELECTRON DONORS FOR TCE DNAPL BIOREMEDIATION
Citation:
DWORATZEK, S., J. ROBERTS, M. HARKNESS, R. ROYER, A. FISHER, E. E. MACK, J. PAYNE, C. BARTLETT, M. THOMSON, M. LEE, D. MAJOR, E. HOOD, C. M. ACHESON, R. F. HERRMANN, J. GERHARD, AND X. MAO. BENCH-SCALE PERFORMANCE OF PARTITIONING ELECTRON DONORS FOR TCE DNAPL BIOREMEDIATION. In Proceedings, Fifth International Conference on Remediation of Chlorinated and Recalcitrant Compounds, Monterey, CA, May 22 - 25, 2006. Battelle Press, Columbus, OH, B-41, ISBN1574771574, (2006).
Impact/Purpose:
To inform the public.
Description:
The objective of the Source Area Bioremediation (SABRE) project, an international collaboration of twelve companies, two government agencies and three research institutions, is to evaluate the performance of enhanced anaerobic bioremediation for the treatment of chlorinated ethene source areas containing dense, non-aqueous phase liquids (DNAPL). This research effort focuses on a pilot-scale demonstration of enhanced bioremediation at a trichloroethene (TCE) DNAPL field site in the United Kingdom, but includes a significant program of laboratory and modeling studies. Given the project's emphasis on enhanced rates of DNAPL removal, the use of water-soluble electron donors that partition into DNAPL (e.g., n-butyl acetate and 1-hexanol) is of particular interest. The current presentation discusses column studies designed to upscale the results of microcosm studies, provide critical data for the design of the field demonstration, and produce high-quality experimental data suitable for numerical model calibration. The performance of the partitioning electron donors will be benchmarked to a commonly-used water soluble electron donor (such as lactate). One-dimensional columns packed with site soil and flushed with a groundwater media will be used to address three primary research objectives: 1) Effects of partitioning electron donors on bioenhanced mass transfer-assess the impact of electron donor (soluble or DNAPL partitioning) on the mass removal of DNAPL under biotic conditions. Mass transfer enhancement factors for each electron donor will be determined; 2) Factors influencing partitioning electron donor transport-assess transport properties of partitioning electron donors through observation of their partitioning behavior in soil. Partitioning phenomena to be studied include adsorption to soil and water:DNAPL partitioning coefficients. Data generated by this study will be used to develop partitioning electron donor dosing strategies (i.e., frequency, concentration) for the pilot study; and 3) Dechlorination efficiency of partitioning electron donors-characterize the extent of hydrogen production through donor fermentation and the efficiency of electron donor utilization by dechlorinating microorganisms relative to other electron-accepting process (e.g., methanogenesis). The experimental data generated by the column studies will be complemented by a comprehensive numerical multicomponent transport model which incorporates the appropriate reaction pathways and kinetics. Successful model calibration will facilitate design of the pilot study and allow meaningful comparisons of alternative electron donor delivery strategies. Column design is currently underway and studies will begin in September 2005 with results expected by March 2006.
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Bench-Scale Performance of Partitioning Electron Donors for TCE DNAPL Bioremediation (PDF, NA pp, 22 KB, about PDF)