“Current Status of SERDP and ESTCP Efforts on PFAS” by Dr. Andrea Leeson
Aqueous Film Forming Foam (AFFF) formulations have been used by the Department of Defense (DoD) since the 1970s to extinguish fires. The DoD used AFFF mixtures containing significant quantities of perfluorooctane sulfonate (PFOS) and related perfluoroalkyl sulfonates such as perfluorohexane sulfonate (PFHxS) until 2002, when production ceased, although the DoD continued to use PFOS-containing AFFF stocks for some time after. Although the DoD’s legacy use of AFFF also included various fluorotelomer-based formulations, the majority of DoD’s environmental liability likely results from the use of PFOS-based AFFF formulations.
Since FY11, SERDP and ESTCP have funded several projects aimed at developing a better understanding of the occurrence, fate and transport, remedial treatment options, and ecotoxicity at AFFF-impacted sites, as well as the development of next generation fluorine-free foams. This presentation provided an overview of these efforts, together with key findings from a SERDP and ESTCP sponsored workshop in May 2017 titled “Research and Development Needs for Management of DoD's PFAS Contaminated Sites”. The May 2017 workshop led to a SERDP solicitation to develop innovative approaches for the treatment of waste derived from PFAS subsurface investigations. This presentation focused on providing project highlights resulting from this solicitation and will conclude with summaries of (1) the FY20 ESTCP Supplemental Solicitation on demonstrating and validating environmentally sustainable methods to clean firefighting delivery systems, (2) the FY21 SERDP Solicitation on improving the understanding of thermal destruction technologies for materials laden with PFAS, and (3) important SERDP and ESTCP PFAS resources.
This project supports SERDP in developing sustainable, cost-effective technologies to treat PFAS contamination in soils or investigation derived wastes (IDW). IDW includes drill soil cuttings and excavated soils and spent activated carbon (GAC) waste streams generated from treating water from well development and sampling.
Smoldering combustion is a self-sustaining process following a short duration, low energy input “ignition event” for low volatility and high energy compounds such as petroleum hydrocarbons. PFAS cannot support smoldering combustion and require temperatures exceeding 900°C for their destruction. This project evaluated GAC as a surrogate fuel that supports smoldering above the 900°C threshold.
PFAS adsorbed to GAC then mixed with sand, or PFAS contaminated soil mixed with uncontaminated GAC were tested. Results show that small amounts of GAC achieve temperatures more than 900°C. Post-treatment concentrations of PFAS in the treated mixtures were below detection limits (0.05 µg/kg). Initial emission analyses indicated that over 82% of the available fluorine was captured as hydrogen fluoride with only small amounts of PFAS emitted which could be subsequently captured by activated carbon and treated. These results suggest that smoldering may provide an effective remediation technique for PFAS-impacted soils and IDW.
Dr. Andrea Leeson is the Deputy Director of SERDP and ESTCP as well as the Program Manager for SERDP and ESTCP’s Environmental Restoration program area. Dr. Leeson has been with SERDP and ESTCP since 2001. Prior to that, she was a Research Leader at Battelle Memorial Institute where she conducted scientific research on in situ bioremediation and the design and implementation of innovative biological, chemical and physical treatment technologies for site remediation and industrial wastewater. She received her doctoral degree in Environmental Engineering from The John Hopkins University.
Dr. Dave Major is the Managing Director of Savron, a division of Geosyntec Consultants, Inc. He has helped develop and commercialize remediation technologies such as zero-valent iron permeable reactive barriers, molecular biomarkers, bioaugmentation cultures, and most recently, Savron’s smoldering-based combustion technology or STAR. Dr. Major has served on various national scientific advisory boards including the U.S. EPA Expert Panel on DNAPL Remediation (The DNAPL Remediation Challenge: Is There a Case for Source Depletion), and the U.S. National Research Council Committee on Geological and Geotechnical Engineering in the New Millennium. He is the receipient of several awards including the University of Waterloo Faculty of Science Alumni of Honour Award (2007) in recognition of his professional accomplishments, the Space Hall of Fame® (2007) for helping NASA commercialize “Products from Space Benefiting Planet Earth”, and the ICE Telford Premium (2016) award for a key paper on ground improvement technology. Dr. Major has led efforts between Geosyntec and University of Toronto, and Savron and University of Western Ontario, that were recognized for national excellence in sustained and innovative academic-industrial collaboration with the Natural Science and Engineering Research Council of Canada Synergy Award in 2009 and 2018. He received his doctoral degree in microbiology and contaminant hydrogeology from the University of Waterloo.