Colloidal Activated Carbon for in situ Remediation of PFAS: A Review of Multiple Case Studies

Presented on Tuesday, December 3, 2019
Kristen Thoreson, Ph.D1, Maureen Dooley2 and Paul Erickson, Ph.D.3, (1)Research & Development, REGENESIS, (2)Regenesis, Wakefield, MA, (3)Research & Development, REGENESIS, San Clemente, CA

The current accepted remediation method for PFAS is to use pump and treat systems equipped with activated carbon or a resin, however the costs associated with running these systems and replacing the adsorbent can be exorbitant. Therefore, the ability to implement an in situ barrier of activated carbon to amend the effective foc of an aquifer and increase the natural retardation factor for these contaminants is an appealing strategy to manage these plumes. This risk-based approach removes PFAS from the mobile phase and eliminates the route of exposure to down-gradient receptors.

This presentation reviews data from multiple field sites where colloidal activated carbon has been utilized to remediate PFAS contamination. Further important questions, including the ability to distribute the colloidal activated carbon in the subsurface, the long-term efficacy, and design considerations, will also be addressed.

Multiple field sites were treated with a single application of colloidal activated carbon to address PFAS contamination and other comingled contaminants. In each case the amendments were applied under low pressure (non-fracking) conditions using direct-push technology. Monitoring at all sites is on-going, with current data ranging from 3 months to over two years, and has included analysis of PFOS, PFOA, shorter chain PFASs, and co-contaminant concentrations.

Results from field case studies have demonstrated immediate removal of PFAS from the dissolved phase to levels below the US EPA health advisory level when treated with a single application of colloidal activated carbon. The site with the longest monitoring period has maintained its performance with PFOS, PFOA as well as shorter chain species for over two years and counting. Overall, these studies indicate that the in situ application of colloidal activated carbon offers a new strategy to address the risk associated with PFAS contamination at a low cost.

Kristen Thoreson, Ph.D
Research & Development, REGENESIS
Dr. Kristen Thoreson leads the chemical research and product development program at REGENESIS. She is trained as a chemist, and her graduate and post-doctorate research focused on mechanistic investigations of chlorinated ethene degradation pathways using molecular models and compound specific isotope analysis (CSIA) for both biotic and abiotic systems. She obtained her BSc in chemistry from the University of Wisconsin – La Crosse, and her PhD in inorganic chemistry from the University of Minnesota. She also spent time as a postdoctoral associate at the Helmholtz Zentrum in Munich, Germany as a part of the Research Unit for Environmental Organic Isotope Chemistry.

Maureen Dooley
REGENESIS, Wakefield, MA
Ms. Dooley has over twenty five years experience in many aspects of environmental industry including project management, research and development, senior technical oversight, remedial design and laboratory management. Ms. Dooley’s current position is the Northeast Region Manager for REGENESIS. She is responsible for managing both sales and technical support associated with REGENESIS bioremediation and chemical oxidation products. As part of her responsibilities at REGENESIS® she has reviewed hundreds of potential projects and provided recommendations for remediation. Much of her work over her career has been focused on the development and implementation of bioremediation programs. Over the past several years, however, she has been focused on chemical oxidation applications at petroleum and chlorinated hydrocarbon sites. Ms. Dooley has drafted hundreds of project proposals, evaluations and reports related to the feasibility of using bioremediation. In addition, prior experience includes the completion of numerous treatability studies designed to evaluate the biodegradation of a wide range of chemical constituents that include chlorinated solvents, petroleum hydrocarbons, explosives, aromatic hydrocarbons and pesticides.

Paul Erickson, Ph.D.
Research & Development, REGENESIS, San Clemente, CA
Paul Erickson, PhD is a Senior Research Scientist with REGENESIS. In his current R&D role, Dr. Erickson collaborates with REGENESIS remediation services, sales, and technical services departments to solve clients’ complex remediation challenges and identify and develop new environmental solutions. Leading the development of the PetroFix Design Assistant application, Dr. Erickson played a central role in bringing PetroFix to market, providing environmental professionals a fast, cost-effective method of treating petroleum contaminants in groundwater. Dr. Erickson holds a BS degree in Chemistry from Florida State University, a Masters in Chemistry from the University of Minnesota, and a PhD in Environmental Chemistry from ETH Zurich.

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