The use of aqueous film-forming foam (AFFF) has led to per- and polyfluoroalkyl substances (PFAS) impacting groundwater throughout the United States. To remediate PFAS-impacted groundwater, treatment technologies capable of high capacity PFAS sequestration from water and concentration of PFAS waste for efficient processing by available destruction technologies are required to ensure full elimination of PFAS waste streams. Conventional adsorption technologies used to remove PFAS from water typically involve single-use granular activated carbon (GAC) or strong anion exchange resins (IXR) that result in large volumes of PFAS-laden solid waste. Cyclopure developed a novel DEXSORB® adsorbent, made with renewable β-cyclodextrins, with high capacity to sequester PFAS from water. Importantly, spent DEXSORB media can be desorbed under ambient conditions providing complete recovery and concentration of extracted PFAS. The objective of this project is to demonstrate the effectiveness of a DEXSORB packed-bed filtration (PBF) system for high capacity PFAS sequestration, followed by desorption and concentration of PFAS waste, in a pilot-scale pump-and-treat system of AFFF-impacted groundwater at a designated DoD site.

The technical approach for this project is organized around five major tasks:

1. Perform a site review, including water sample collection for characterization of general water quality and PFAS impact profile, to facilitate the engineering design and installation of a DEXSORB PBF system;
2. Procure, mobilize, and install the DEXSORB PBF system at the designated DoD site;
3. Use the DEXSORB PBF system to treat AFFF-impacted groundwater for a demonstration period of six months at predetermined hydraulic conditions, with periodic water sampling before and after PBF treatment to monitor PFAS breakthrough;
4. Desorb and separate extracted PFAS from spent DEXSORB media by system backwash with a desorption solution, with sample collection from the PFAS-containing desorption solution to measure desorbed PFAS and confirm mass balance; and
5. Decommission and demobilize the DEXSORB PBF system after the six-month demonstration period, and analyze all data collected to evaluate the system performance for (i) PFAS sequestration from AFFF-impacted groundwater, (ii) bed volume capacity, and (iii) PFAS desorption and concentration.

The project team will review performance data and O&M records to make recommendations for full-scale DEXSORB PBF system design and installation for pump-and-treat groundwater treatment.

The completion of this demonstration project will enable the full-scale design of DEXSORB PBF for pump-and-treat systems. This will provide an alternative treatment solution that is distinguished from single-use adsorption technologies with (i) effective, high capacity PFAS sequestration, and (ii) quantitative PFAS desorption from spent media into concentrated form for processing by downstream destruction technologies. Key deliverables of this work include system performance data of PFAS sequestration, media capacity, and waste stream concentration, pilot-scale O&M data, and PFAS-containing desorption solution for further processing by destruction technologies in other funded research projects. The project outcomes and deliverables generated from this work will benefit site managers, persons responsible for the management and remediation of AFFF-impacted groundwater, and downstream PFAS destruction practitioners. (Anticipated Project Completion - 2025)