This study is designed to demonstrate the efficacy of regenerable anion exchange resin (AER) for the treatment of a wide range of per- and polylfluoroalkyl substances (PFAS). The main objective is to meet the proposed maximum contaminant levels set by the U.S. Environmental Protection Agency and extend this treatment approach to encompass various PFAS analytes, including perfluorobutanoic acid.

The enduring performance of regenerable AER in treating PFAS in impacted groundwater over multiple cycles will be assessed, eliminating the need for frequent replacement and preserving treatment capacity. Additionally, the waste reduction capabilities of regenerable AER treatment will be demonstrated, and a PFAS aqueous waste concentrate will be generated, suitable for on-site destructive treatment. This concentrate can be seamlessly integrated into the regenerable AER treatment system, creating a closed-loop PFAS treatment solution. Finally, a comprehensive comparative life cycle cost assessment will be conducted, taking into account both the initial investment and ongoing operational costs, to provide a thorough evaluation of regenerable AER in comparison to alternative treatment media such as single-use AER and granular activated carbon.

In this prototype, groundwater is directed through vessels containing regenerable AER, which facilitates the separation of PFAS from the impacted groundwater via a combined process involving hydrophobic-based adsorption, electrostatic interactions, and ion exchange, primarily targeting anionic compounds. A tandem configuration of two vessels is employed, in a lead/lag configuration. Upon reaching saturation of PFAS within the lead vessel, indicated by the presence of the target PFAS species surpassing treatment thresholds in the effluent, the lead vessel is removed from operation. A solvent-brine regeneration solution is utilized in situ to restore the adsorptive capacity of the exhausted media (referred to as "regeneration"). Subsequently, the lag vessel transitions to take the role of the lead vessel, thereby ensuring uninterrupted operation. The formerly employed lead vessel undergoes regeneration and returns into service without necessitating the procurement of fresh media. Regeneration involves on-site distillation to reclaim the solvent for use in subsequent cycles. The residual solution, also known as the "still bottom," contains a substantial PFAS concentration, up to 50,000 times that of the influent water. The still bottom is forwarded to various specialized technology vendors for further destructive treatment.

This prototype serves as a demonstrative platform for the treatment of PFAS in impacted groundwater, aligning with drinking water standards and meeting the levels for short-chain PFAS. The media is regenerated on-site through the application of a solvent-brine solution, resulting in the production of a highly concentrated PFAS solution, subsequently subjected to distillation before transfer to designated destruction technology vendors.

This prototype technology offers several important advantages: it effectively treats PFAS-impacted water to meet stringent regulatory standards, enabling the safe and sustainable reuse of the treated water. The employed technology is highly adaptable, capable of meeting evolving regulatory requirements by adjusting the media type and regeneration frequency. Furthermore, it produces a concentrated PFAS waste stream (still bottoms) essential for cost-effective PFAS destruction processes. It substantially reduces the need for off-site disposal of PFAS treatment media, reducing environmental impact and associated costs. (Anticipated Project Completion - 2025)