Field Demonstration\nof PFAS Destruction in Various\nAlcohol-Resistant AFFFs Using Supercritical Water Oxidation (SCWO)

Aqueous film-forming foams (AFFFs) have been used for\nover 60 years\nto control dangerous Class B fires, but their firefighting efficacy\nis owed to per- and poly fluoroalkyl substances (PFAS), which have\nemerged as concerning persistent contaminants for the environment\nand human health. Battelle’s PFAS Annihilator, a supercritical\nwater oxidation (SCWO) technology, demonstrated ≥3 log destruction\nof PFAS in each of the three alcohol-resistant AFFF formulations from\ndifferent manufacturers. A comparison between dilutions (6–16%)\nranging from 1.9 to 64 ppm PFAS similarly demonstrated >99.9% destruction\nfor all AFFF dilutions. Minimal reactor corrosion is indicated based\non the reactor metals’ concentrations measured in the effluent,\namounting to just 0.0004% (∼83 mg) wall loss per hour of operation.\nA similar approach estimates the formation of ∼3.1 g of precipitated\nsalts in the reactor per hour of operation. A fluorine mass balance\nyielded 40% excess fluorine in the effluent compared to the influent,\nindicating a lot of unquantifiable nontarget PFAS precursors in the\nAFFF formulations. SCWO’s economic efficiency is demonstrated\nto be dependent on the volume of fluid processed, not upon the PFAS\nconcentration or formulation chemistries, suggesting that the SCWO\ntechnology would be even more economical for highly contaminated streams.