Aerobic Cometabolic Biodegradation to Treat Emerging Chemicals and Co-Contaminants in Dilute Plumes

Tuesday, August 8, 2017: 2:25 p.m.
Min-Ying Chu, Ph.D., PE , Haley & Aldrich, Inc., Oakland, CA
Peter Bennett, CHG, P.G. , Haley & Aldrich, Inc., Oakland, CA
Murray Einarson, P.G., C.E.G. , Haley & Aldrich, Inc., Oakland, CA

One of the major challenges in managing large dilute plumes is treating recalcitrant emerging contaminants such as 1,4-dioxane (14D), 1,2,3-trichloropropane, and N-Nitroso-dimethylamine. Conventional technologies (e.g., in situ anaerobic bioremediation or ex situ granular carbon adsorption) selected to treat primary contaminants (e.g., chlorinated solvent compounds) are often inadequate to treat emerging contaminants. Aerobic cometabolic biodegradation has been considered a promising remedial technology that can concurrently treat a wide spectrum of organic contaminants to very low concentrations. The feasibility of concurrent treatment of all contaminants via the aerobic cometabolic biodegradation process was demonstrated at the former McClellan Air Force Base site in California. The primary substrates, HD10 propane and oxygen, were added to recirculated groundwater to stimulate the aerobic cometabolic activity of the indigenous microbial population in situ. The treatment results show that 14D can be treated to concentrations below 1 ug/L and co-contaminants trichloroethene, 1,2-dichloroethane, and 1,1dichlorehene can be concurrently treated to their respective analytical method detection limits of 0.23, 0.18, and 0.2 ug/L, respectively. The degrading activity lasts for more than two weeks without the addition of primary substrates, indicating the stability and robustness of the treatment process. The treatment efficiencies are contaminant specific, ranging from 90 to 99%, comparable to the efficiencies observed in other similar field studies that used significantly higher primary substrate loading rates. In this presentation, the insights gained from this demonstration field test will be shared; various potential applications, including different suites of contaminants, various types of substrates, enhanced natural attenuation, and mass flux management will be presented. Finally, implementation of in situ aerobic cometabolic biodegradation under various large dilute plume scenarios will be described.

Min-Ying Chu, Ph.D., PE, Haley & Aldrich, Inc., Oakland, CA
Dr. Min-Ying Jacob Chu is a Senior Engineer at Haley & Aldrich, Inc. His expertise includes groundwater modeling, vadose zone transport processes, environmental microbiology, remedial system design, and system behavior evaluation. He has published numerous journal articles in the topics of reactive transport modeling, mass transfer, and bioremediation. Dr. Chu has a Ph.D. in Environmental Science and Engineering from Stanford University. He received his Master of Science degree in Environmental Engineering from Oregon State University and earned his Bachelor of Science degree from National Taiwan University.

Peter Bennett, CHG, P.G., Haley & Aldrich, Inc., Oakland, CA
Mr. Bennett has more than 14 years of experience with innovative site characterization and remediation projects. He has served as the project manager and technical lead for several Superfund sites in California and routinely assists his clients in reducing the costs and liabilities associated with old chemical releases. Much of his practical experience includes work at sites with commingled (multisource) plumes, vapor intrusion concerns, and property development. He has implemented low cost in-situ remediation programs at several sites as alternatives to groundwater extraction.

Murray Einarson, P.G., C.E.G., Haley & Aldrich, Inc., Oakland, CA
Mr. Einarson has 30 years of experience in the development, testing, and application of innovative approaches and technologies for cost-effective environmental site characterization and in-situ remediation. He has been an instructor in the Princeton Remediation course and the University of Waterloo graduate course in field hydrogeology for the last 10 years. Mr. Einarson has provided technical training in subsurface characterization and groundwater monitoring for Regional Water Quality Control Board staff every year for the last five years. He is also a recipient of the Ground Water Technology Award from the National Ground Water Association in 2009.