Long-Term Performance of Enhanced Anaerobic Bioremediation and the Occurrence of Sustained Treatment at Chlorinated Solvent Sites
Bedient, Philip B.
Master of Science
The objective of this research was to evaluate the long-term performance of enhanced anaerobic bioremediation (EAB) at chlorinated solvent sites and the occurrence of sustained treatment following EAB. A database of groundwater concentration versus time records was compiled for 25 sites with at least three years of post-treatment data. The median post-treatment monitoring period for these sites was 5.2 years, with a maximum of 11.7 years. Long-term performance was evaluated based on concentration changes from before treatment to the final year of post-treatment monitoring. Results indicate that the median concentration reduction for all 25 sites was approximately 80%, just under 1 order of magnitude. Sustained treatment, where concentrations remain suppressed after ceasing active treatment, was evaluated using a lines-of-evidence approach including analysis of rebound, statistical concentration trends after treatment, and decay rates from before and after treatment. Results indicate that sustained treatment is occurring at a majority of the sites.
Bioremediation; Chlorinated solvent; Sustained treatment