Transitioning from Active Remedies to Monitored Natural Attenuation
Many contaminated sites use active remedies such as pump-and-treat or in situ remediation to clean up impacted groundwater. Natural attenuation processes such as natural degradation or hydrodynamic dispersion also contribute to the cleanup. As remediation progresses, a point is often reached when the time required to reach the remedial objectives using the active remedy is roughly the same as the time required if the active remedy is shut down, and the continuing remediation of the site is provided by natural attenuation processes alone. From that point forward, the extra effort and expense of the active remedy provides no benefit over natural attenuation, and it may be appropriate to transition the site to Monitored Natural Attenuation (MNA). This presentation deals with currently available tools and approaches that can be used to support a decision to transition from active remediation to MNA.
Presenters:
Dr. John Wilson has extensive experience in natural attenuation processes and bioremediation. He is currently the Principal Scientist with Scissortail Environmental Solutions, LLC. Dr. Wilson served as a research microbiologist for U.S. EPA at the R.S. Kerr Environmental Research Center in Ada, Oklahoma for 35 years. He has a B.S. in Biology from Baylor University, an M.A. in Microbiology from the University of California at Berkeley, and a Ph.D. in Microbiology from Cornell University. His research for EPA was primarily on natural attenuation of BTEX compounds, fuel additives, and chlorinated solvents, as well as in-situ bioremediation of chlorinated solvents. He has over 60 publications on these topics. He was a co-author and edited the U.S. EPA Report titled A Guide for Assessing Biodegradation and Source Identification of Organic Ground Water Contaminants using Compound Specific Isotope Analysis (CSIA). In addition to his research activities, he provided training and technical assistance to the EPA regions and to state agencies.
Dr. Newell is a Vice President with GSI Environmental Inc. and has more than 30 years of experience managing environmental engineering projects. He is a member of the American Academy of Environmental Engineers, a NGWA Certified Groundwater Professional, and an Adjunct Professor at Rice University. His professional expertise includes site characterization, groundwater modeling, non-aqueous phase liquids, source zones, remediation performance, risk assessment, natural attenuation, bioremediation, non-point source studies, software development, and long-term monitoring projects. He has also served as a technical facilitator for groups trying to reach consensus regarding complex environmental issues.
Dr. Adamson is a Senior Environmental Engineer at GSI Environmental Inc. with more than 15 years of environmental project experience that includes site investigation, characterization, and remediation, with projects in the U.S., Europe, Latin America, and the Middle East. He has extensive expertise in projects dealing with natural attenuation, source zone characterization, emerging contaminants, matrix diffusion, and the development and testing of innovative monitoring and treatment technologies. He was a coauthor of the DoD‐sponsored guidance document “Frequently‐Asked Questions About MNA” and was one of three co‐instructors for the DoD sponsored “Massive Open Online Course” (MOOC) on MNA.