On December 18, 2020, the United States Environmental Protection Agency (EPA) released interim guidance on destruction and disposal of Perfluoroalkyl and Polyfluoroalkyl (PFAS) and materials containing PFAS (including aqueous film-forming foam, or AFFF). EPA notably ranks interim storage of such materials for the next two to five years as most protective of the environment and encourages that option where possible until there is further research available on the risk of potential harm associated with other disposal options. Based on current information, EPA ranks combustion and other thermal treatment as least protective of the environment.
The interim guidance document provides comprehensive technical information on various disposal methods that EPA has evaluated, including thermal treatment, landfill, and underground injection technologies, and describes the uncertainties associated with each method of disposal. Based on research currently available, EPA provides a ranking of disposal options based on likelihood that the disposal method may harm the environment.
EPA provides the following ranking of disposal methods for PFAS and PFAS-containing materials, from least risk of harm to greatest amount of risk of harm to the environment:
- Interim storage: Due to the uncertainties currently associated with disposal or destruction of PFAS or PFAS-containing materials, EPA encourages storage for the next two to five years if immediate destruction or disposal is not imperative.
- Permitted deep well injection (Class I): EPA notes that deep-well injection is feasible and effective for a limited amount of liquid-phase waste streams. Because there are limited wells currently receiving PFAS, however, waste transportation and costs associated with permitted deep well injection likely limits the practicability of this disposal option.
- Permitted hazardous waste landfills (RCRA Subtitle C): These facilities have the most stringent environmental controls in place, making it more likely that the migration of PFAS into the environment will be minimized.
- Solid waste landfills (RCRA Subtitle D) that have composite liners and leachate collection and treatment systems: While these landfills have environmental controls in place, EPA notes that proper management of landfill gaseous and liquid releases must be considered and that special care must be taken to apply leachate control technologies that are effective at containing or destroying PFAS. A high level of uncertainty remains regarding PFAS behavior in landfills, with further research needed on the effects of PFAS on liner integrity and the effectiveness of leachate treatment for PFAS removal.
- Hazardous waste combustors: This category includes commercial incinerators, cement kilns, and lightweight aggregate kilns. According to EPA, these technologies can potentially achieve temperatures and residence times sufficient to break apart the PFAS contained in the waste stream, but EPA has no emission characterizations from facilities accepting PFAS-containing waste to establish regulatory controls that would be protective of the environment.
- Other thermal treatment: Carbon reactivation units, sewage sludge incinerators, municipal waste combustors, and thermal oxidizers are all included in this category. Just as with combustion above, EPA indicates that it has little information on the effectiveness of these technologies for eliminating the risk of harm PFAS pose to the environment.
EPA hopes the information in the document will assist managers disposing of PFAS or PFAS-containing materials in making informed decisions about destruction and disposal that are most protective of the environment, and anticipates reviewing and updating the guidance within the next three years to reflect ongoing research regarding PFAS destruction and disposal technologies.
The interim guidance is open for public comment until February 22, 2021.