The overall objective of this project is to demonstrate an innovative treatment train for complete destruction of aqueous film-forming foam (AFFF) concentrates. The technology will be tested to determine the capability to degrade the high concentrations of per- and polyfluoroalkyl substances (PFAS) and other organics in AFFF. This technology will fill a critical gap of non-thermal AFFF destruction technology.

Specific objectives are as follows:

1. Demonstrate the effectiveness of the technology for destroying, at minimum, an older C8-based AFFF and one fluorotelomer-based AFFF under field conditions.
2. Design and construct a mobile, on-site treatment unit that can be used to treat the above mentioned AFFF concentrates at different sites.
3. Collect field data (technical and cost) to support full-scale application evaluations.

The treatment train is based on comprehensive, laboratory-validated approaches. It incorporates three novel technologies:

1. AFFF concentrate is initially digested using mechanochemical wet ball milling, which activates persulfate to break down precursors into known PFAS while also destroying organic surfactants and reducing foaming potential
2. The pre-treated AFFF is then rinsed from the ball mills and subjected to ultraviolet (UV)/sulfite reduction, destroying most PFAS and converting some perfluorinated compounds into polyfluorinated structures.
3. Finally, the effluent undergoes electrochemical oxidation (EO), resulting in near-complete defluorination of residual PFAS into fluoride ions

This treatment train leverages the complementary advantages of each step. First, ball milling is effective in removing non-fluorinated organic matter in AFFF originating from hydrocarbon surfactants and other AFFF constituents and significantly reducing foaming, which is critical for the following UV/sulfite and EO steps. Second, a recent study indicated that tandem UV/sulfite and EO treatment is mechanistically complementary for each process to realize near quantitative defluorination of diluted AFFF. Third, chemicals added in the ball milling (initially sodium persulfate, then converted to sulfate) and UV/sulfite (sodium sulfite and sodium hydroxide) steps can be used as electrolytes and a source of sulfate radicals in EO treatment. This process design minimizes the use of chemicals.

This project will demonstrate an innovative non-thermal destructive technology for treating AFFF concentrates. If successful, results from this work will provide an improved capability to cost-effectively manage legacy AFFF concentrates. The technology will offer an on-site treatment technology, thereby reducing or avoiding expensive alternatives. Specific expected benefits include providing a non-thermal treatment solution that can achieve near-complete destruction of PFAS and organic additives in AFFF concentrates and offering a solution that operates under ambient conditions with low energy use. A successful demonstration of this technology will provide an affordable, deployable solution to protect critical installations and personnel, bolstering national defense capabilities. (Anticipated Project Completion - 2027)