The overall objective of this project is to demonstrate the effectiveness of a novel thermal steam plasma technology for the destruction of fluorinated surfactants in aqueous film-forming foam (AFFF) concentrates. The thermal steam plasma technology offers a single step treatment process through direct injection, requiring no dilution of the AFFF concentrate prior to treatment and eliminating additional management or handling of the source material (e.g., transfer to larger tanks, mechanical mixing, pumps, hosing, etc.).

This project will center around an extensive field demonstration of the skid-mounted plasma treatment unit where AFFF concentrates of varying physical properties will be treated to evaluate the robustness, operational reliability, and treatment performance of this direct-injection treatment approach. Given the complex nature of AFFF concentrates, a significant analytical component will be included in the field trial to characterize the AFFF sources and assess the level of defluorination and mineralization of the concentrates through the thermal treatment process (e.g., vapor sampling and analysis via Other Test Method (OTM)-45 and OTM-50). Specific project objectives are: 1) treat three different formulations of AFFF concentrates with a skid-mounted 100 kW thermal steam plasma unit (see image below); 2) conduct treatment process validation with the field operational data; and 3) calculate life cycle costs for the system.

Thermal Steam Plasma

Thermal steam plasma is an innovative and proven per- and polyfluoroalkyl substances (PFAS) treatment technology that can atomize PFAS and other compounds in the vapor waste stream under ultra-high temperature of approximately 2500^oK without developing shorter-chain PFAS (e.g., perfluorobutanesulfonic acid, perfluorobutanoic acid) or other derivatives. In a typical thermal steam plasma process for PFAS-containing waste, destruction begins with the vaporization of PFAS-impacted liquid (e.g., AFFF) as it is injected into the ultra-high temperature plasma reactor, and the remaining process occurs in plasma states. Unlike combustion-based heating where temperatures have an upper limit of ~1,200^oC, the thermal steam technology can achieve much higher temperatures (> 2000^oC; via electrical joule heating) and breakdown very recalcitrant compounds at atmospheric pressures.

For this ESTCP effort, the project team plans to demonstrate the thermal steam plasma treatment system for the treatment of AFFF concentrates, resulting in destruction of fluorosurfactants and other AFFF components and sequestration of fluorine in sodium fluoride. AFFF concentrate can be directly injected into the steam plasma plume for instant vaporization and breakdown of PFAS. Any other chemicals present in the vaporized AFFF concentrate are broken down into its elemental form, providing complete destruction.

The goal of this project is to offer a practical option for management of legacy AFFF stockpiles. Synergen Met’s Thermal Steam Plasma process is a well-developed technology for the destruction of PFAS and simultaneous mineralization of fluorine atoms. The ultra-high temperature achieved by the plasma torch provides the unique advantage of “broad-spectrum” destruction via complete atomization of any compounds with limited operational constraints and direct injection of AFFF concentrates to largely simplify the management of this waste stream. This demonstration will fully test the suitability of this technology for treatment of AFFF concentrates, ultimately fortifying the Department of Defense's operational capabilities and securing warfighter preparedness. (Anticipated Project Completion - 2026)