A Mobile Supercritical Water Oxidation Reactor for Destruction of PFAS-Impacted Wastes

Due to their thermochemical stability and unique properties, per- and polyfluoroalkyl substances (PFAS) have been used extensively for Department of Navy (DON) firefighting applications. PFAS are long-lived in the environment and coming under increased regulatory scrutiny, presenting DON installations with significant environmental compliance and remediation challenges when undertaking construction, dewatering, soil remediation, or wastewater treatment activities.Typically, removing PFAS from water during water treatment or wastewater treatment involves using solid sorbent materials, including granular activated carbon (GAC) or ion exchange resin (IXR). GAC and IXR each have a useful lifespan during which PFAS can be removed to below regulatory thresholds, after which the materials must be disposed of.In the SBIR Phase I base project, the Aquagga and UW team demonstrated that PFAS-laden sorbents can be continuously processed and treated in a lab-scale, supercritical water oxidation (SCWO) reactor. Both PFOA- and PFBS-laden sorbents were successfully treated, validating that SCWO can be used for the final treatment and disposal of spent sorbents. In the proposed Phase II effort, we seek to design, fabricate, and validate a scaled-up SCWO reactor to treat solid sorbent materials.By the end of the Phase II project, we will fabricate and validate a technology readiness level (TRL) 6 SCWO reactor, which can be utilized for DoD and commercial PFAS disposal applications. Key success metrics include (i) demonstrating the ignition of the SCWO reactor and (ii) continuous operation at T > 600 °C for > 6 h with multiple slurry and liquid feedstocks in the pilot-scale SCWO system.The combined Aquagga and University of Washington project team has deep expertise in the development of supercritical water reactor systems, PFAS treatment and destruction, analytical chemistry techniques for demonstrating effective PFAS mineralization, and technology scale-up and commercialization.