The main objective of this project is to demonstrate the effectiveness of a supercritical water oxidation (SCWO) process for eliminating per- and polyfluoroalkyl substances (PFAS) from a variety of waste streams including aqueous and solid media such as granulated activated charcoal or ion exchange resin beads. Processing solid media requires a slurry to be made after grinding particles to an appropriate size that allows for consistent feed to the oxidation reactor. Therefore, another goal of this project includes the development of a feed preparation step as a precursor to processing the solid media. The overall goal of this project is to demonstrate with verifiable data that the integrated prototype industrial SCWO (iSCWO) system is a viable destruction technology for PFAS-impacted waste.

Through process optimization and engineering refinement, the SCWO technology has been packaged into a suitable industrial SCWO system that can process most industrial liquid or slurry wastes to destroy hydrocarbons. The technology utilizes a large reactor vessel with appropriate materials to avoid salt buildup and corrosion, a caustic addition to neutralize any inorganic acids at the reactor outlet, and numerous safety devices to prevent thermal runaway or pressure releases.

The GA Electromagnetic Systems (GA-EMS) iSCWO system operates nominally at 650^oC and 3,400 pounds per square inch. At this condition, hydrocarbons become miscible within the supercritical water environment allowing for rapid oxidation to carbon dioxide and water, while precluding the formation of nitrogen oxides that are typically found in incinerator emissions. A rapid quench of reactor products also eliminates the potential to form products of incomplete combustion such as dioxins or furans (when processing chlorinated hydrocarbons).

The standard iSCWO system can receive up to three gallons per minute of process fluids which includes water, fuel, and waste. Oxygen is provided by a high-pressure air compressor. The system software maintains temperature through fuel (typically diesel) input control. As waste feed is initiated, the system automatically balances the water and fuel input to ensure the proper energy input and therefore temperature control. Most notably, if the waste to be processed contains sufficient energy content, both water and diesel fuel can be eliminated such that the iSCWO system is operating entirely on the waste and compressed air provided.

Eliminating PFAS from the environment without generating new wastes or emissions that can be similarly hazardous to the environment, has reached a critical stage for ensuring human health and wildlife safety. Many technologies under investigation for removing PFAS are showing promise; however, a final stage of destruction is still under question.

An evaluation of the GA-EMS iSCWO system is an important step in establishing appropriate tools for addressing the issue of destroying PFAS. This project includes a thorough investigation of liquid effluent and gaseous emissions to confirm to what extent PFAS has been eliminated when processing a variety of waste streams. Once verified, the iSCWO system could be considered a promising technology for eliminating PFAS found in a variety of waste streams. (Anticipated Project Completion - 2025).