This project will demonstrate the efficacy of a supercritical water oxidation (SCWO) technology to destroy per- and polyfluoroalkyl substances (PFAS) in multiple types of impacted media, including but not limited to, groundwater, investigation-derived waste (IDW), landfill leachate, fire-fighting training area water, and aqueous film-forming foam (AFFF) distribution system fluids and associated appurtenances. These impacted media will contain dilute (part per trillion to low part per million) concentrations of PFAS. SCWO will be used to treat multiple types of impacted media that have been pretreated by one or more removal/concentration technologies, which may include foam fractionation, reverse osmosis, distillation, ion exchange regenerant or others. A semi-quantitative mass balance will be performed by analyzing target PFAS, inorganic fluoride, and total organofluorine concentrations, and will be supported by non-target PFAS analyses, to validate that complete mineralization of PFAS has been achieved.

SCWO is a process that occurs above the supercritical point of water in the presence of oxygen (greater than 374 °C and 22 MPa). At or above these conditions, there is no distinction between gas and liquid, and the properties of the fluid change dramatically, facilitating mass transfer and reaction kinetics. The carbon-fluorine bond dissociation energy is overcome, and PFAS are mineralized to products including carbon dioxide, water, hydrofluoric acid (which is subsequently neutralized), and salts. SCWO differentiates itself from other PFAS remediation technologies in that it can completely mineralize PFAS, requires a short residence time, is effective on all PFAS congeners, is not inhibited by organic co-occurring chemicals, can treat dilute and concentrated media, and generates little waste. 

A mobile SCWO system, capable of treating up to 500-gallon per day (gpd) will be deployed to a facility to destroy PFAS in a variety of PFAS-impacted media generated by technologies that remove/concentrate PFAS, but do not mineralize them. Specific demonstration objectives include: 

• Demonstrate that SCWO can achieve greater than 99% destruction in one or more types of concentrated feed and demonstrate that the final polished effluent can meet applicable state regulatory discharge requirements. 
• Demonstrate that byproducts in the liquid and vapor phases are not generated or can be cost-effectively removed during the polishing step prior to discharge. 
• Achieve a semi-quantitative mass balance by analyzing target PFAS, inorganic fluoride, and total organofluorine concentrations in the influent and effluent streams, supported by analysis of (about 500) non-target PFAS. 
• Establish a realistic treatment cost (cost/1,000 gallons per destruction efficiency) for this technology.

This project will demonstrate the efficacy of the PFAS Annihilator™ to perform on-site destruction of PFAS in a variety of types of concentrated media to achieve greater than 99% destruction of PFAS and achieve applicable regulatory discharge requirements without the creation of significant byproducts, and will establish a treatment cost for this technology for different media types. Combined as a treatment train with a technology that concentrates, but does not destroy PFAS, it will provide a powerful tool to eliminate PFAS from large dilute sources of impacted media. A successful outcome of this effort will provide the basis to establish a cradle-to-grave solution for a wide range of PFAS-impacted waste. Furthermore, successful application of the PFAS Annihilator™ to completely mineralize PFAS will mitigate DoD’s potential long-term liability associated with disposing concentrated PFAS-impacted materials in landfills. (Anticipated Project Completion - 2026)