The presence of per- and polyfluoroalkyl substances (PFAS) in the environment poses a distinct challenge. PFAS are widely used and long-lasting chemicals that have been associated with adverse human health outcomes. In March 2023, The U.S. Environment Protection Agency (EPA) announced a proposed National Primary Drinking Water Regulation for six PFAS including perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid, hexafluoropropylene oxide dimer acid (commonly known as GenX Chemicals), perfluorohexane sulfonic acid, and perfluorobutane sulfonic acid. While general sources of PFAS in the environment abound, impact to groundwater and surface waters arising from the historical use of Class B aqueous film‐forming foam used for firefighting and training purposes is a major liability. The overall objective of this project is to demonstrate and validate Surface Active Foam Fractionation (SAFF®) as a commercial off-the-shelf PFAS removal technology for treatment of impacted waters.

SAFF® is a foam fractionation technology invented in Australia by OPEC Systems that is being distributed in North America by Allonnia. SAFF® comprises a train of foam fractionation stages that are installed in series and operate in a semi-batch mode. Foam fractionation is an adsorptive bubble separation technique that can remove amphiphilic species dissolved in an aqueous solution. Amphiphiles (or surfactants) tend to adsorb onto the surface of rising bubbles (i.e., airwater interfaces) according to their adsorption coefficient. The first SAFF® stage (primary fractionator) ‘strips’ PFAS from impacted feed and produces a PFAS-depleted effluent that will generally meet discharge requirements. The primary foamate containing the PFAS comprises the feed to the second stage (secondary fractionation), which concentrates the foamate to a factor of over 5,000:1. If further concentration is desired, the enriched secondary foamate, or super-concentrate, from the secondary unit can be fed through a separate, containerized third stage (tertiary fractionation) system, to produce a highly enriched PFAS hyper-concentrate at a factor of over 200,000:1 (in some cases much higher). The super- or hyper-concentrate represents a low-volume, high-concentration, aqueous PFAS solution that is uniquely suitable for destruction by any number of emerging destruction technologies. Thus, SAFF® addresses the treatment of PFAS-impacted groundwater or stormwater via removal and concentration. The SAFF® concentrate can be shipped off-site or be destroyed by an on-site destruction technology. During this field demonstration, success will be measured by:

1. demonstration of effective PFAS treatment by SAFF® over a 6-month operating period in a range of seasonal conditions (e.g., temperature), including achieving the 2023 proposed EPA Maximum Contaminant Levels using post-SAFF® polishing if necessary;
2. enhanced foaming and PFAS short-chain removal using Allonnia’s proprietary SAFF “booster” compound(s);
3. enhanced PFAS removal via electrolyte addition (an alternative booster option);
4. demonstration of hyper-concentration of PFAS using an additional containerized tertiary fractionation system; and
5. validation of limited release/exposure potential from airborne (i.e., aerosolized) PFAS.

This project will demonstrate that SAFF® represents a tremendous improvement to existing technologies for PFAS treatment, and provides a year-round, safe, cost-effective, and sustainable means to aid the country's water security. SAFF® has been proven to remove >99.8% of PFOS and PFOA without the use of chemicals or absorption media. Where air alone cannot meet discharge requirements for specific applications, SAFF booster compounds can easily be added to improve removal of shorter chain PFAS to regulatory limits. Furthermore, the low volume, high density PFAS concentrate is ideal for either on-site or off-site destruction. The potential for a combined technology train to provide a closed-loop, on-site technology for complete PFAS treatment is a unique benefit of SAFF(R), which also avoids any potential long-term risk of transferring impacted media for off-site disposal or destruction. (Anticipated Project Completion - 2025)