Developing Innovative Treatment Technologies for PFAS 

What are the conventional methods for treating PFAS?

Conventional PFAS treatment technologies focus on removing PFAS from contaminated water rather than destroying them. These methods include:

• Granular Activated Carbon (GAC): GAC is the most commonly used PFAS treatment technology. GAC is effective for removing long-chain PFAS, such as perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), but it has lower efficiency for short-chain compounds like perfluorobutanesulfonic acid (PFBS) and perfluorobutanoic acid (PFBA).
• Ion Exchange Resins: Anion exchange resins (AER) contain positively charged polymeric material that attract and remove negatively charged PFAS molecules from the water. AER can effectively remove a wide range of PFAS compounds; however, the resin is typically more expensive than GAC. Single-use AER has been shown to be more cost effective than a regenerable ion exchange resins, which generate waste streams that require further management.
• Reverse Osmosis: High-pressure membranes, such as reverse osmosis, are more than 90 percent effective at removing PFAS, including short-chain PFAS. Approximately 80 to 90 percent of the feed water passes through the membrane as treated water. Approximately 10 to 20 percent of the feedwater is retained as a high-strength concentrated waste. This technology may be best suited as a point of-use technology for a homeowner.
• Foam Fractionation: Emerging methods such as foam fractionation use air bubbles to concentrate PFAS into a foam, which is then removed and further treated. Foam fractionation is relatively simple and cost-effective, and when combined with destructive technologies, it can serve as an efficient PFAS management strategy.

While these methods effectively remove PFAS from water, they do not destroy PFAS from water. To address this challenge, Tetra Tech’s emerging contaminant experts are evaluating advanced destruction technologies that can break PFAS down into harmless byproducts.

What technologies are available for the destruction of PFAS compounds?

Tetra Tech is working with the U.S. Department of Defense (DoD) Environmental Security Technology Certification Program (ESTCP) to design, fabricate, and demonstrate a prototype mobile electron beam (eBeam) system for on-site treatment of soils and sediments impacted by PFAS. The project supports the DoD in restoring the environment and protecting the safety of our service members and the health of our communities.

Electron beam technology stands out due its use in several environments including treatment of contaminants in wastewater, biosolids, groundwater, sludges, soil, and sediments. eBeam is a destructive technology that uses high-energy electrons to generate reactive electrons that break carbon-fluorine bonds in PFAS. The process simultaneously creates both reduction and oxidation reactions without the addition of any chemicals.

Tetra Tech applies its Leading with Science® approach to research and advance a range of PFAS destruction technologies applicable to all media, while also avoiding the production of problematic chemical byproducts. Some of the most promising methods include ultrasound technology, plasma technology, supercritical water oxidation, electron beam, and ball milling.

What challenges remain in scaling PFAS destruction technologies?

Scaling up PFAS destruction technologies is hindered by the persistence and complex chemistry of PFAS. The presence of co-contaminants that may interfere with treatment, the higher resistance of short-chain PFAS to removal, and the formation of harmful byproducts in some methods further complicate effective treatment. Other key challenges include high energy demands of some destruction technologies, scalability issues where lab-scale success does not always translate to large-scale applications, and the efficiency of some methods to fully eliminate PFAS. Additionally, high costs can be a barrier to large-scale implementation. Developing effective, sustainable, and scalable PFAS destruction technologies requires addressing these challenges while minimizing costs and environmental risks.

Tetra Tech has a proven track record of evaluating and scaling innovative technologies for the treatment and destruction of PFAS contaminants. Learn more about how we are helping clients proactively manage risks and uncertainties related to PFAS and other emerging contaminants.