Destruction of Per- and Polyfluoroalkyl Substances (PFAS) via Lacasse Enzymatic Degradation and Electrochemical Advanced Oxidation

Abstract

This report outlines a two-step treatment technology that has been designed for the destruction of per-and polyfluoroalkyl substances (PFAS) in contaminated water, with a focus on perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). PFOA and PFOS contaminated groundwater water will first flow through reverse osmosis (RO) and foam fractionation (FF) units to separate and concentrate PFOS and PFOA compounds. The contaminated foam waste will be directed to the laccase enzyme immobilized polyvinylidene fluoride (PVDF) membranes with a flow rate of 5 gallons per day (gpd) and a starting PFOA and PFOS concentration of 10 parts per million (ppm). The enzymes will break down the PFOA and PFOS into shorter chained PFAS with an estimated 35% efficiency rate. These shorter chains will subsequently be destroyed in an electrochemical oxidation treatment unit, along with the remaining PFOA and PFOS. The full-scale design will reduce the PFOA and PFOS concentration to less than 50 parts per trillion (ppt), meeting the Environmental Protection Agency (EPA) health advisory level of 70 ppt. To ensure the advisory level is met, the effluent from the electrochemical oxidation treatment unit will be recirculated through the RO and FF unit, ensuring that the only effluent leaving the system is from the RO and FF pre-treatment units with acceptable PFOA and PFOS concentrations.