Professor, Department of Civil and Environmental Engineering
Colorado School of Mines
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 (NREL). He is also a member of the Re-inventing the Nation’s Urban Water Infrastructure (ReNUWIt) Engineering Research Center. His research focuses on the development of innovative technologies for remediation and destruction of perfluoro- and polyfluoroalkyl substances (PFASs), 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, and his research has been sponsored by DoD-SERDP, AFCEC, NSF, USDA, and DOE. Prof. Strathmann is also currently serving as an Associate Editor for Environmental Science & Technology. His formal training includes a PhD in environmental engineering from Johns Hopkins, BS and MS degrees from Purdue, and postdoctoral training at Princeton University.
An Innovative Hydrothermal Destruction Technology that Achieves Rapid and Complete Defluorination of PFASs
Timothy J. Strathmann, Shilai Hao, Boran Wu, Christopher P. Higgins, Rula Deeb
Colorado School of Mines, Department of Civil and Environmental Engineering Geosyntec Consultants, Oakland, CA
This presentation will introduce an innovative technology for destruction of per- and polyfluoroalkyl substances (PFASs) that is widely applicable for treatment of contaminated water and soil samples. Hydrothermal processing applies elevated temperatures (200 – 375 C) and pressure (5 – 22 MPa) to liquid phase water to create unique reactive properties that promote organic chemical decomposition. Hydrothermal processing is ideal for high moisture content samples (e.g., water, wet soils) and much less energy intensive than competing thermochemical technologies (e.g., incineration) because volatilization of the water is avoided. I will present results from recent experiments that demonstrate rapid and complete degradation and defluorination of PFASs identified in aqueous film-forming foam (AFFF) solutions and AFFF-impacted water and soil samples, including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). This conclusion is supported by complementary information from ion selective electrode analysis for fluoride ion release, liquid chromatography with quantitative time-of-flight mass spectrometry (LC-QToF-MS), and nuclear magnetic resonance (19F-NMR) spectroscopy that will be presented. A tentative mechanism for PFAS decomposition will be presented and potential applications for hydrothermal processing of PFAS-contaminated concentrate byproduct streams (e.g., thermal soil treatment condensates) will be discussed.