Biogeochemically Enhanced Treatment of Chlorinated Organics and Metals
Daniel Leigh, P.G., CHG, Technology Applications Manager, Evonik Active Oxygens, LLC
This presentation will briefly cover the basic biological and geochemical processes which occur when applying reductive technologies for in situ treatment of chlorinated organics and metals. It will describe in more detail how these processes synergistically generate reactive iron-sulfide (FeS) minerals that can enhance treatment these contaminants. Small amounts of these reactive minerals are usually produced naturally during reductive treatment at many sites. The formation of these minerals creates a separate biogeochemical treatment pathway that can abiotically degrade chlorinated organics and sequester many toxic metals. Most reductive approaches for treatment of these contaminants can be greatly enhanced by application of substrates designed to synergistically increase this biogeochemical pathway by simultaneously generating large quantities of reactive minerals and increasing the effectiveness of chemical reductants, such as zero valent iron. Data from bench, pilot and full-scale field studies from sites where biogeochemically enhanced reductive processes have been applied for in situ treatment of chlorinated organics and metals will be presented.
Dan Leigh is the Technology Applications Manager for In Situ Reductive Technologies at Evonik Active Oxygens, LLC. He is a registered geologist and hydrogeologist with more than 35 years of experience in contaminated site evaluation and remediation; over 30 of which has been focused on treatment of chlorinated organics and metals. He has designed and conducted assessment and remediation projects across the United States and Internationally. Dan has authored over 200 publications and technical presentations spanning the areas of geology, hydrogeology, atoll island and coastal groundwater hydrogeology, geochemistry, natural attenuation, aerobic, anaerobic, and co-metabolic bioremediation, bioaugmentation, biogeochemical degradation, and in situ chemical reduction for treatment of chlorinated organics and metals. He was the Principal Investigator for the US Air Force BAA program Biogeochemical Processes Technology Evaluation Research and Development grant in 2010. He continues to evaluate and develop methods that improve the application and effectiveness of these technologies.