Novel Method to Enhance Chlorinated Solvent Biodegradation by the Use of Barriers, 2001 Int

Abstract: Physical containment has several advantages for managing chlorinated solvent plumes, but is not considered at many sites because of the perception that it does not remove or destroy contaminant mass. Because of this perception, other remediation approaches that do remove mass are often favored, even if they remove it slowly (such as natural attenuation) or are expensive (long-term pumping). Our biodegradation research indicates that barrier systems will result in increased contaminant destruction at many chlorinated solvent sites. Chlorinated solvent biodegradation occurs when electron donors (carbon substrates that form dissolved hydrogen) are utilized by naturally-occurring dechlorinating bacteria in the subsurface to consume electron acceptors (the chlorinated solvents). This process occurs naturally at many sites (when source materials contain both solvents and electron donors), and can be enhanced by supplementing the electron donor supply. However, our research shows that the efficiency of naturally-occurring and enhanced biodegradation is compromised by the transport of competing electron acceptors (i.e., dissolved oxygen, nitrate, and sulfate) to solvent biodegradation zones via the flow of clean upgradient groundwater through the source