This project seeks to evaluate through direct measurement the ability of high temperature incineration to destroy per- and polyfluoroalkyl substances (PFAS). Actual test data are needed to confirm the ability of incineration to destroy PFAS at high efficiency. The research will focus on a mass balance of PFAS incineration within a rotary kiln cement facility, and will demonstrate as a first step that PFAS-containing wastes can be successfully incinerated with minimal PFAS emissions to air. More specific goals will be to (i) demonstrate the degree of PFAS destruction; (ii) identify the fate of the fluorine liberated during PFAS decomposition; and (iii) evaluate the likely cost-effectiveness of incineration relative to other PFAS destruction technologies.
A mass balance approach will be applied to targeted PFAS to estimate their fate and destruction efficiencies in a high temperature combustion process designed to burn/destroy organic hazardous wastes. Testing will be conducted in a combustion facility that provides long combustion gas residence times at high temperatures such as a thermal oxidizer or fluidized bed boiler. PFAS and related fluorine parameters will be measured to examine fluorine flows in and out of the combustion process. Aqueous film-forming foam (AFFF) will be injected into the combustion device at sufficient PFAS loads to be measurable in stack emissions assuming limited destruction. Stack emissions will be measured using the U.S. Environmental Protection Agency’s draft Other Test Method (OTM) 45 method designed specifically for PFAS, with possible extensions to examine nonpolar PFAS. Stack exhaust will also be analyzed by fourier-transform infrared (FTIR) spectroscopy to look for short-chain PFAS such as carbon tetrafluoride and hexafluoroethane that may be present as residual products of incomplete combustion. Process samples (e.g., ash) will be collected during the stack test period and analyzed for PFAS to check for PFAS transfer to these materials. Destruction efficiencies will be estimated from the differences between the amount of PFAS introduced to the combustion process less the amounts measurable in combustion effluents and process streams. The effectiveness and cost of high temperature incineration will be compared with other data and information on other treatment methods as available.
Viable disposal options are needed for managing PFAS-containing wastes and materials that are preferably destructive in nature (and not simply sequestering). These waste streams include impacted soil and drill cuttings, spent granular activated carbon, spent resin, filtered sludge and filter bags, piping used for AFFF, and concrete. Stack testing will evaluate PFAS destruction to inform on the degree to which incineration destroys PFAS, and hence its reliability as a safe and effective PFAS disposal option. If incineration of PFAS waste is shown to destroy PFAS at high efficiency, this would provide a method to permanently destroy PFAS-containing materials releasing any future liability. (Anticipated Project Completion - 2024)