Tackling PFAS in Water Reuse: Science, Regulation, and Solutions – Key takeaways from our last webinar
PFAS (per- and polyfluoroalkyl substances) present one of the most complex challenges facing water reuse today. Their widespread use, extreme persistence, and uncertain health impacts make them difficult to regulate, treat, and ultimately destroy. In this context, our latest webinar (11DEC2025) brought together leading international experts to explore the latest science, policy perspectives, and practical approaches for managing PFAS in water reuse systems.
John Fawell, Visiting Professor at Cranfield University and member of the WHO Expert Group on Drinking Water Guidelines, kicked off our webinar with his introductory presentation “PFAS – A complication for re-use of wastewater”. John explained that while concern is growing, robust toxicological data exist for only a small number of compounds, creating major uncertainty for risk assessment. Regulatory limits therefore vary widely and often reflect precautionary approaches that may drive costly and difficult-to-reverse investments. Encouragingly, experience shows that phasing out key PFAS can significantly reduce human exposure. Looking ahead, John emphasised the need for science-based standards that balance PFAS risks with broader water supply and treatment realities.
Focusing on treatment technologies, Roberta Hofman-Caris (Principal Scientist Water Treatment & Resource Recovery, KWR, Netherlands) presented insights into chemical degradation of PFAS using advanced reduction and anodic oxidation. While conventional treatment can remove PFAS, it largely shifts contamination to waste streams rather than destroying the compounds. Advanced reduction shows promise, particularly for PFAS carboxylates, but requires extreme conditions and performs poorly in real water matrices, especially in the presence of nitrate. Anodic oxidation, by contrast, demonstrated strong potential, achieving over 80% PFAS degradation in real concentrate streams and emerging as a promising route for tackling “forever chemicals”.
Following on Roberta’s presentation, Valérie Léveillé (Waters treatment engineer, WSP, Canada) introduced the P-Phaser electro-oxidation system, a destructive PFAS treatment technology based on boron-doped diamond electrodes. Now full-scale ready, the system delivers high PFAS destruction rates (95–99%), long electrode lifetimes, and modular deployment across groundwater, wastewater, and concentrate streams. Importantly, a patent-pending process addresses perchlorate formation, enabling non-detectable levels. The technology is particularly well suited to high-concentration, low-flow applications, offering rapid treatment, no sludge production, and strong return on investment.
Finally, , providing a large-scale operational perspective, Jason S. Dadakis (Executive Director Water Quality and Technical Resources, Orange County Water District, USA) shared lessons from the Orange County Water District’s Groundwater Replenishment System (GWRS), the world’s largest indirect potable reuse system, producing around 500,000 m³/day of purified water. Jason reminded the audience that Reverse osmosis is a highly effective process to remove PFAS from finished water, but concentrates them in challenging brine streams. Orange County is therefore piloting destructive solutions, including electro-oxidation, supercritical water oxidation, and vacuum UV, while simultaneously delivering one of the largest groundwater PFAS treatment programmes worldwide—an effort approaching USD 600 million in investment.
Missed our webinar? WRE Members can catch-up with our recording in the members area of our website
