GRACast: Remediation of Poly-and Perfluoroalkyl Contaminants Using In Situ Chemical Oxidation: A Laboratory Study
Presented by:
Tom Bruton, Ph.D.
Green Science Policy Institute
The use of aqueous film-forming foams (AFFF) for extinguishing flammable liquid fires has led to contamination of groundwater with poly- and perfluoroalkyl substances (PFASs). Sorption to activated carbon is the current presumptive remedy for PFAS contamination, but in situ chemical oxidation (ISCO) has also received attention as a possible treatment strategy because of its potential to mineralize, rather than sequester, these compounds. This presentation will describe research that investigated the fate of different PFASs under conditions intended to simulate subsurface treatment using chemical oxidants. Laboratory experiments were performed by amending solutions of PFOA or PFOS with either Fenton’s reagent or heat-activated persulfate. Of these two treatments, only heat-activated persulfate effectively transformed PFOA, and its efficacy was related to solution pH. Neither treatment resulted in transformation of PFOS. Heat-activated persulfate experiments were also carried out using samples of AFFF from two manufacturers. In experiments using fluorotelomer-based AFFF, full removal was observed for the primary PFAS component, 6:2 fluorotelomer thioether amido sulfonate (6:2 FtTAoS). 6:2 FtTAoS was transformed into a suite of perfluorinated carboxylates with varying fluorocarbon chain length. During oxidative treatment of perfluorooctane sulfonyl-fluoride based AFFF, perfluorinated sulfonate components were unaffected, but sulfonamide-based polyfluorinated compounds were transformed into perfluorinated carboxylates. Heat activated persulfate treatment carried out at low pH may be a feasible remedial strategy for groundwater impacted by polyfluorinated compounds and perfluorocarboxylates.
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SPEAKER BIO:
Dr. Tom Bruton recently received his Ph.D. from the Department of Civil and Environmental Engineering at UC Berkeley, where his dissertation research explored using chemical oxidation to degrade poly- and perfluoroalkyl substances (PFASs) in the context of groundwater remediation. Prior to that, Tom received his bachelor’s and master’s degrees from Iowa State University and Arizona State University, respectively, and worked as an environmental engineering consultant.
In February of this year, Tom joined the Green Science Policy Institute, as the Institute’s first Science and Policy Fellow. In his work at GSPI, Tom collaborates with partners in business, government, NGOs, and academia to promote the responsible use of PFASs and other chemical classes of concern in products.
MODERATOR BIO:
Erika Houtz, PhD, PFAS Analytical Lead
Dr. Houtz has eight years of academic and professional experience investigating the environmental impacts of PFAS. She has extensive experience in developing analytical and experimental methods for the measurement of PFAS in environmental and human samples. She has also investigated and published on the fate and transport of PFAS in natural and engineered systems, with a particular emphasis on the fate of PFAS found in aqueous film forming foams. Since joining Arcadis in 2016, she has been engaged in numerous PFAS projects, including developing guidance for site characterization, developing conceptual site models at contaminated sites, evaluating the efficacy of treatment technologies, working with laboratories to commercialize new PFAS analysis techniques, and tracking of the evolving PFAS regulatory landscape in the U.S. and globally.
Date: Sept. 27, 2017, noon - Sept. 27, 2017, 1 p.m.