The objective of this project is to design, build, and demonstrate an integrated ex situ per- and polyfluoroalkyl substance (PFAS) treatment system consisting of high-recovery closed-circuit membrane filtration (CCMF), surface active foam fractionation (SAFF), and hydrothermal alkaline treatment (HALT) for PFAS removal, concentration, and destruction of waste streams that may not be amenable to treatment via adsorption technologies. This integrated system was developed to overcome challenges related to PFAS treatment and residual disposal. It incorporates PFAS treatment, PFAS residual volume reduction (and concentration of PFAS), and PFAS destruction using advanced treatment processes. The integrated system will be mobilized to a Department of Defense (DoD) site and evaluated for four months in treating a PFAS-impacted water matrix. Data, including individual process operating data, treatment train operating data, water quality data, and PFAS effluent concentrations, will be collected and used to validate the treatment train. PFAS removal, residual management, and energy consumption will be used as metrics as a basis for comparison to other PFAS treatment technologies.

This treatment train consists of three 'plug-and-play' technologies that have been developed and/or validated individually by the research team through DoD-funded research programs, including SERDP and ESTCP:

1. A CCMF capable of producing PFAS-free water at >97% recovery (>33x reduction of PFAS waste volume).
2. A semi-continuous, low-energy SAFF^® system to remove and further enrich the PFAS in the reject stream by at least 1,000 times more.
3. A HALT system to destroy the PFAS-laden foam fractionates.

The management of high-strength (parts per billion to parts per million concentrations) PFAS wastes, such as firefighting delivery equipment rinsates, investigation-derived wastes, and groundwater or residuals emanating from fire training areas with elevated organic content (greater than 1 milligram per liter - mg/L), is of concern given the ineffectiveness of adsorbent-based processes (e.g., ion-exchange, activated carbon) for their treatment.

There is a significant need for methodologies to effectively pre-concentrate these PFAS residual streams leading to economical PFAS destruction using available technologies such as HALT. This project will address this need by demonstrating an integrated treatment train capable of removing, concentrating, and destroying PFAS present in impacted aqueous waste streams that may be difficult to treat using conventional adsorption technologies. (Anticipated Project Completion - 2025)