Afrooz Bayat (AECOM, NZ), Rachael Casson (AECOM, Australia), Christopher Curran (AECOM, USA)
Per- and Poly-fluoroalkyl substances (PFAS) have a wide range of applications from firefighting foams and fireproofing to cookware coating, due to the unique specification of this substance. PFAS are very resistant to thermal and chemical changes and the strong carbon fluorine (C-F) covalent bond makes it a very popular commercial substance for manufacturing non-stick cookware and grease-proofing agents. To date, over 9,000 compounds in the PFAS family have been identified (NIOSH, 2021). The PFAS family and the uses of these substances have been growing ever since the initial compounds were manufactured. The unique physical and chemical properties of PFAS compounds make them highly recalcitrant and persistent, which result in non-treated PFAS being detected in various waste streams, surface water, groundwater, and drinking water. Even in small quantities, consumption of PFAS can harm human health. Such health effects can include carcinogenesis, endocrine disruption, infertility, birth defects, and neurotoxicity. The adverse health effects from PFAS have raised significant concerns worldwide which has led to various governmental guidelines and regulations (ITRC, 2022).
Common approaches for removing PFAS from water streams rely on separation (via different media, reverse osmosis or foam fractionation). Notably, many research entities are also focusing on PFAS destruction technologies that rely on advanced oxidation processes (AOPs) such as super critical water oxidation (SCWO), plasma and electrochemical oxidation (EO). More effective treatment processes including nanofiltration and reverse osmosis have been studied. However, these remediation techniques usually face other challenges such as fouling and they generate PFAS-concentrated waste that requires further treatment.
Advanced redox reactions such as electrochemical oxidation are emerging treatment methods that are the most efficient technologies in removing PFAS without leaving downstream by-products. These technologies can be energyefficient as they can utilise renewable energy such as solar energy. AECOM, in association with Georgia University, are developing an innovative treatment technology for degrading aqueous PFAS from water and waste streams. Results of bench and pilot trials have demonstrated degradation efficiencies up to 99%.
Unlike other treatment technologies that use separation techniques, this technology aims to destroy the PFAS mass. DE FLUOROTM has been tested in Australia on various water and wastewater streams. Research results show that this technology has the potential to successfully destroy dissolved phase PFAS mass in a cost- and energy-efficient manner on-site.