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Destruction of PFAS in Concentrated Waste Streams with High Current Density Electrochemical Processes Dr. Tim Mollart, Principal Application Engineer, Element Six (UK) Ltd. Rapid progress is beingmade in filtration and concentrating technology to remediate trace concentrations of per- and polyfluoroalkyl substances (PFAS) contamination fromground, industrial waste and drinking water streams. With the proliferation of PFAS compounds and the mixed nature of waste streams, there is interest in flexible PFAS destruction processes which are capable of destroying both small-scale, a few micrograms per day from a manufacturing site to larger scale, a few grams of PFAS per day generated by large metropolitan drinkingwater treatment plants. Typical concentrated PFAS effluents can reach starting concentrations of 1 to 100mgL-1 range, in backgrounds of 100 to 1000׳s mgL-1 of total organic carbon (TOC) and high total dissolved solids (TDS). While conventional advanced oxidation processes are capable of breaking long chain, carbon chains > 8 along with these TOC and TDS backgrounds, there are relatively fewprocesses capable of breaking down short chain PFASmaterials, such as Perfluorobutane sulfonate (PFBS) and Perfluorobutanoic acid (PFBA). Boron doped diamond (BBD) electrodes are chemically inert and have been shown to be capable of directly oxidizing PFAS compounds in aqueous solutions, generating adsorbed hydroxyl radicals for traditional advanced oxidation processes. Free standing BDD electrodes allow to access extremely high current density oxidation (>5000 Am-2) using bipolar electrochemical cells that lend themselves to the electrochemical destruction of PFAS compounds. This talk outlines the manufacturing process and properties of Element Six׳s free standing BDD electrodes and how they are packaged into compact electrochemical cells that deliver effective PFAS destruction technologies. Destruction data from treatment trials of foam fractionated landfill leachate waste streams is shown, with particular attention to the destruction of short chain PFAS species. The advantages and limitations of electrochemical PFAS destruction will be explored, together with the implementation of these destruction systems, whicharenowemerging as apractical solution for PFAS destruction. מושב איכות מים ומיקרו מזהמים יו״ר קרן בן מלאכי, יועצת