“Laboratory and Modeling Investigation of PFAS Transformation, Transport, and Retention in AFFF Source Areas” by Dr. Linda M. Abriola (SERDP Project Webpage)
This SERDP project was designed to address gaps in our understanding of processes that control the transport, retention and transformation of PFAS in the subsurface and to use this information to develop mathematical models and assessment tools for site managers. Research activities encompass batch and column experiments, as well as mathematical modeling and decision tool development. This presentation summarized results of experiments undertaken with selected PFAS compounds and mixtures to quantify interfacial accumulation and sorption processes for reference and field-collected soils. An industry-standard numerical simulator, HYDRUS, modified to account for experimental findings, was used to explore the influence of these retention processes on PFAS transport and fate. Results exploring microbial transformation of selected perfluoroalkyl acid precursors under different redox conditions in media collected from aqueous film-forming foam (AFFF)-impacted sites at Robins Air Force Base were also discussed. The project team engaged practitioners and site managers in the development of simulation scenarios that realistically capture conditions encountered at DoD field sites. Combining experimental findings with mathematical modeling of realistic field scenarios will enable the future identification and assessment of PFAS mobility at AFFF-impacted sites and support the development of practitioner-oriented decision tools to aid management and remediation of PFAS-impacted sites.
“Hydrothermal ALkaline Treatment (HALT): An Innovative Technology for Complete Destruction of PFAS in Water and Soil” by Dr. Timothy Strathmann (SERDP Project Webpage)
This webinar presented results from a SERDP project which introduces an innovative technology for complete destruction of PFAS in both aqueous and wet soil matrices, referred to as HALT (ydrothermal kaline reatment). HALT applies elevated temperatures (250 – 375 degrees Celsius) and pressures (5 – 22 Megapascals) to liquid phase water amended with low-cost alkalis such as sodium hydroxide to create unique reactive properties that promote rapid defluorination and destruction of PFAS. HALT is ideal for treating high moisture content wastes (e.g., water, wet soils, wastewater biosolids) impacted by PFAS because volatilization of water is avoided and input energy requirements are therefore much lower than competing thermochemical technologies such as incineration, gasification, and pyrolysis. Results were presented showing treatment of a wide range of PFAS identified in AFFF solutions and AFFF-impacted water and soil samples, including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). This included evidence obtained from high resolution liquid chromatography with quantitative time-of-flight mass spectrometry (LC-QToF-MS), nuclear magnetic resonance (19F-NMR) spectroscopy, and fluoride ion analysis. Potential applications of this patent-pending technology were also discussed.
Dr. Linda M. Abriola is University Professor and Director of Tufts Institute of the Environment at Tufts University in Massachusetts. From 2003 to 2015, she served as the Dean of the Tufts University School of Engineering. Prior to joining Tufts, she was the Horace Williams King Collegiate Professor of Environmental Engineering at the University of Michigan in Ann Arbor. Dr. Abriola is an expert in the multiphase transport, fate, and recovery/destruction of contaminants in the subsurface. She has authored more than 150 refereed publications. She is a member of the National Academy of Engineering and Fellow of the American Academy of Arts and Sciences and the American Geophysical Union. She has been the recipient of numerous awards, including the National Ground Water Association’s Distinguished Darcy Lectureship (1996) and the SERDP Project of the Year Award in Remediation (2006, 2012. Her many professional activities include service on the U.S. EPA Science Advisory Board, the National Academies Water Science and Technology Board, and the Stockholm Environment USA Board of Directors. Dr. Abriola received a bachelor’s degree from Drexel University, and master’s and doctoral degrees from Princeton University, all in civil engineering.
Dr. Timothy Strathmann is a professor in the Department Civil and Environmental Engineering at the Colorado School of Mines and holds a collaborative researcher appointment at the National Renewable Energy Laboratory. He is also a member of the Re-inventing the Nation’s Urban Water Infrastructure Engineering Research Center. His research focuses on the development of innovative technologies for remediation and destruction of PFAS, and the advancement of hydrothermal processes for valorizing waste streams by producing fuels, fertilizers and other valuable products from these resources. Dr. Strathmann is the recipient of a National Science Foundation CAREER Award. His research has been sponsored by SERDP, the Air Force Civil Engineer Center, the National Science Foundation, the U.S. Department of Agriculture, and the Department of Energy. Dr. Strathmann is currently serving as an Associate Editor for Environmental Science & Technology. He received bachelor’s and master’s degrees from Purdue University, and a doctoral degree in environmental engineering from Johns Hopkins.