The primary objectives of this project are 1) to establish a physical testbed and technology testing framework for side-by-side assessment of treatment techniques for sediments impacted by per- and polyfluoroalkyl substances (PFAS), and 2) to develop and test prototype treatment technologies and treatment trains for destruction of PFAS associated with soils and sediments impacted by aqueous film-forming foam (AFFF).

Once the physical testbed and testing framework are established, five prototype treatments or treatment trains will be assessed. This effort will establish a testbed and use a standardized sediment PFAS treatment technology testing framework to independently evaluate technology performance side-by-side. Moreover, this project will assess several fundamentally different sediment treatment technologies (or treatment trains), and for one of the suggested treatment trains, several destructive technologies.

Researchers at Colorado School of Mines have partnered with Texas Tech University, University of California at Berkeley, Geosyntec Consultants, Inc. (Geosyntec) and six different developers of field-ready technologies with significant experience leading applied research projects and field demonstrations, designing prototypes, and commercializing technologies. The project team will evaluate three different sediment treatment technologies as well as three destructive technologies that can handle concentrated waste streams. The side-by-side approach to technology field demonstration meets a critical research need. Each technology will be evaluated using multiple lines of evidence within an independent framework developed by team members to allow for a meaningful comparison of technologies. The three primary technologies to be evaluated include smoldering (Savron), thermal desorption (TerraTherm), and soil washing with foam fractionation (PFAS Foam Assisted Soil Treatment; Allonnia). Further, liquid waste streams generated from these primary technologies, particularly soil washing, will be used to further test hydrothermal alkaline treatment (Aquagga), supercritical water oxidation (374Water) and ultraviolet-activated silica-based granular media (University of Missouri, Kansas City).

Following the completion of field activities and receipt of laboratory analytical results, the team will compile analytical results and field records to assess technology performance relative to metrics. The Framework evaluation team will evaluate technology cost and performance from a life cycle perspective, taking into account energy, cost, and other considerations required by treatment trains/sediment management approaches. Using a lines of evidence approach with common metrics will allow for a meaningful comparison of treatment train alternatives and their ability to meet site-specific objectives. This approach will allow results to be extrapolated/generalized to scaled-up volumes of soils and wastes containing PFAS as well as other sediment types, moisture content, co-occurring chemicals, and other factors affecting treatment efficacy. 

While many vendors have proposed sediment PFAS treatment technologies, each has typically been evaluated by itself at one or more demonstration sites. Side-by-side comparisons of different technologies coupled with an independent assessment of treatment efficacy is a critical data need for DoD. In particular, all technologies should be evaluated in the context of multiple lines of evidence indicating PFAS removal and/or destruction. Information to assess the feasibility of full-scale technology deployment, such as power and materials consumption, are also needed to enable meaningful comparisons. (Anticipated Project Completion - 2025)