Effect of chemical oxidation on in-situ biodegradation of chlorinated solvents

The effect of chemical oxidation pilot studies on in-situ biodegradation of chlorinated solvents in groundwater was evaluated at a dense, non-aqueous phase liquid (DNAPL) in fractured bedrock site in New Jersey, USA. In-situ biodegradation is a component of the site-wide groundwater remedy, to be used as a follow-up to chemical oxidation (otherwise known as a polishing strategy). To evaluate the effect of chemical oxidation on in-situ biodegradation, site data were collected before, during, and after chemical oxidation pilot studies. Results show that short-duration chemical oxidation pilot studies did not adversely affect in-situ biodegradation in the short term, and in-situ solvent biodegradation was enhanced in the fractured bedrock aquifer. We hypothesize that one of the chemical oxidation injectants (i.e., acetic acid) was used as a carbon source by subsurface microorganisms during solvent biodegradation reactions.