The Department of Defense has been using aqueous film forming foam (AFFF) since the 1970s to suppress fires. Due to this use, there are numerous sites with related per-and polyfluoroalkyl substance (PFAS) impact. With the increase in investigations to determine the extent of PFAS impact, large quantities of investigation-derived waste (IDW) are being generated. In 2018, SERDP initiated a suite of projects to develop technologies capable of more cost effective, on-site treatment of these waste materials. All selected projects are one-year, proof-of-concept approaches and are further described below.
Several projects are focused on a treatment train approach to combine multiple technologies into a system for use on different media as well as PFAS and other co-occurring chemicals. Dr. Hyeok Choi at the University of Texas, Austin is leading a project focused on the development of an integrated system of effective treatment technologies for adsorption and degradation of PFAS using physical adsorption, advanced oxidation, and reductive defluorination (Project Web Page). At the University of California, Riverside, Dr. Jinyong Liu is developing a treatment system using advanced oxidation, hydrated electron defluorination, and membrane-based concentration treatment train to remove PFAS from IDW (Project Web Page). Dr. Lisa Yu at Amriton, LLC is leading a project to explore a treatment system using a three-step process of adsorption, desorption, and destruction for the ultimate on-site disposal of treated water and soil (Project Web Page).
Another technology being studied is the use of electrochemical technologies. Dr. Brian Chaplin at the University of Illinois, Chicago is working to develop a cost-effective reactive electrochemical membrane for destruction of PFAS in IDW water samples (Project Web Page). At the University of California, Los Angeles, Dr. David Jassby and his team are researching the development of a combined photo/electrochemical reduction process using reduced activation energy for degradation of PFAS and other co-occurring chemicals (Project Web Page).
The use of thermal treatment technologies is also being evaluated for the destruction of PFAS-impacted IDW wastes. At Colorado School of Mines, Dr. Timothy Strathmann is evaluating the effectiveness of hydrothermal conversion technologies coupled with reactive amendments to degrade and defluorinate PFAS (Project Web Page). Dr. Paul Koster van Groos at APTIM Federal Services, LLC is researching thermal treatment of PFAS in IDW materials along with using calcium hydroxide amendments to lower the energy use and reduce off-gases of potential concern (Project Web Page). At EA Engineering, Science, and Technology, Inc., Frank Barranco is working on evaluating the efficiency of thermal desorption coupled with Indirect Thermal Desorption/Thermal Oxidation technology to treat PFAS-impacted solid IDW (Project Web Page). Mr. James Hatton and his team from CH2M Hill, Inc. are working to demonstrate the use of infrared thermal desorption and off-gas capture as an effective field treatment for subsurface IDW impacted by PFAS (Project Web Page). At Geosyntec Consultants, Dr. David Major is focused on demonstrating the use of smoldering combustion to treat both solid and liquid IDW as well as investigate the emissions created to ensure complete destruction of PFAS (Project Web Page).
Several projects are studying complete destruction of PFAS using nanoscale level technology. At Research Triangle Institute, Dr. Zachary Hendren and his team are working to develop a process using a silicon carbon (SiC)- and graphene quantum dot-based catalyst in combination with ultraviolet light to destroy PFAS molecules (Project Web Page). Dr. Dongye Zhao at Auburn University is working on developing a novel composite material with an activated carbon core and a photocatalyst shell of titanate nanotubes with high adsorption capacity and photochemical degradation and regeneration capability toward PFAS (Project Web Page). At Clemson University, Dr. Ezra Cates and his team are researching the use of a bismuth phosphate (BiPO4)-based photocatalytic material in a commercially available water treatment system for the treatment of PFAS-impacted groundwater (Project Web Page). Dr. Hailiang Dong and his team at Miami University are working on a project to develop a chitosan-modified montmorillonite nano-composite as a “green chemistry” approach to effectively degrade PFAS in IDW (Project Web Page).
Two projects are focused on the use of plasma based processes as a treatment for IDW impacted by PFAS. Dr. Christopher Sales at Drexel University is researching the application of a dielectric barrier discharge to enhance the use of cold plasma to degrade PFAS in IDW (Project Web Page). At Clarkson University, Dr. Thomas Holsen and his project team are studying the use of an integrated sorption/plasma reactor to remove PFAS onto an ion exchange resin follower by desorption and destruction of the PFAS using a validated plasma technique. In addition, the team will look at the use of the plasma reactor to treat soil washing solutions (Project Web Page).
Finally, Dr. Thomas Boving and his team at the University of Rhode Island (Project Web Page) will demonstrate an ex situ treatment approach using a patented peroxone activated persulfate oxidation process for the on-site treatment of PFAS-impacted soil and water IDW. At Texas A&M University, Dr. Suresh Pillai is leading a study on the use of high energy electron beam (eBeam) technology as a destructive treatment. Using spiked and field samples, the effectiveness of this eBeam technology destructive capabilities will be quantified and characterized (Project Web Page).
Summaries of these research projects are available on the SERDP and ESTCP website and all reports originating from these efforts will be available from the project web pages.