Electrochemical Oxidation for Treatment of PFAS in Contaminated Water and Fractionated Foam?A Pilot-Scale Study

Per-and polyfluoroalkyl substances (PFAS) are persistent synthetic contaminants that are present globally in water and are exceptionally difficult to remove during conventional water treatment processes. Here, we demonstrate a practical treatment train that combines foam fractionation to concentrate PFAS from groundwater and landfill leachate, followed by an electrochemical oxidation (EO) step to degrade the PFAS. The study combined an up-scaled experimental approach with thorough characterization strategies, including target analysis, PFAS sum parameters, and toxicity testing. Additionally, the EO kinetics were successfully reproduced by a newly developed coupled numerical model. The mean total PFAS degradation over the designed treatment train reached 50%, with long-and short-chain PFAS degrading up to 86 and 31%, respectively. The treatment resulted in a decrease in the toxic potency of the water, as assessed by transthyretin binding and bacterial bioluminescence bioassays. Moreover, the extractable organofluorine concentration of the water decreased by up to 44%. Together, these findings provide an improved understanding of a promising and practical approach for on-site remediation of PFAS-contaminated water.

Automated summary

We present a practical treatment train that combines foam fractionation and electrochemical oxidation to effectively remove persistent PFAS contaminants from water. The study used an experimental approach, characterizing the process through target analysis, PFAS sum parameters, and toxicity testing. Results were successfully reproduced through a newly developed numerical model. The treatment train achieved an average degradation of 50% for total PFAS, with significant degradation of long-chain and short-chain PFAS. The treatment also reduced the toxicity and extractable organofluorine concentration of the water.