EA evaluated the effectiveness of indirect thermal desorption (ITD) coupled with thermal oxidation (TO) technology to treat solid PFAS-impacted investigation-derived waste. The overall objective of this project was to advance the current understanding of the effectiveness of ITD/TOs for the treatment of soil containing the typical suite of PFASs found in, but not limited to, aqueous film-forming foam formulations manufactured prior to 2002. The assessment of an innovative use of this mature technology provided critical technology performance data to aid in identification of optimal treatment parameters and facilitate an inventory of PFAS contaminants and by-product waste stream destruction during ITD/TO treatment. EA’s research team evaluated if PFAS in soil (investigation-derived waste) can be treated (to low part per billion levels) and off-gas mineralized at temperatures readily achievable with standard commercial scale, rotary kiln-type indirect fired thermal desorption units coupled with thermal oxidizer. The study used recently developed PFAS sampling methods for this project to measure TO off-gas emissions to quantify contaminant destruction/removal efficiencies. This study helped determine if commercial ITD/TO units can successfully be scaled, mobilized, and permitted as either a standalone soil and sediment remedial technology or as a potential treatment train component for solid matrices derived from liquid investigation-derived waste (e.g., sludge, filter cakes, or water treatment media). It is anticipated that the future demand for PFAS-impacted soil and adsorbent media treatment will increase due to additional volumes of investigation-derived waste generated from remedial investigations or to address PFAS-impacted soil incidentally encountered during other military deconstruction and construction activities.
