Reductive Anaerobic Biological In Situ Treatment Technology Treatability Testing

Abstract : The chemical properties of the chlorinated solvents perchloroethene (PCE) and trichloroethene (TCE) are particularly difficult groundwater contaminants to remediate, but laboratory research and field observations have shown that PCE and TCE may be reductively dechlorinated to ethene by microorganisms indigenous to contaminated environments (DiStefano et al. 1991; Major et al. 1991). These findings led to the rapid development of a variety of enhanced biological reductive dechlorination (EBRD) technologies that seek to exploit the remedial capabilities of these microorganisms. Although EBRD shows great potential to effectively treat chlorinated solvent plumes, it is seldom employed because those responsible for implementing site cleanups do not always have a complete understanding of the reductive dechlorination process. Even at sites with laboratory and/or field data that strongly suggest a positive outcome using EBRD technologies, the best method to apply this type of in situ approach has not been clear. Despite concerns regarding its application, EBRD still promises to be a very cost-effective tool for remediating sites contaminated with chloroethenes. It was envisioned that a standardized protocol might serve to alleviate concerns and foster its use at favorable sites while preventing its implementation at inappropriate sites. This led to the development of a draft technical protocol entitled, A Treatability Test for Evaluating the Potential Applicability of the Reductive Anaerobic Biological In Situ Treatment Technology (RABITT) to Remediate Chloroethenes (Battelle, 1997). This document, which would become more commonly known as the RABITT protocol, presents detailed instructions for assessing the applicability of in situ enhanced biological reductive dechlorination at a specific site. The RABITT project consisted of three specific objectives.