April 12, 2024
On April 9, 2024, the U.S. Environmental Protection Agency (EPA) released its Interim Guidance on the Destruction and Disposal of Perfluoroalkyl and Polyfluoroalkyl Substance and Materials Containing Perfluoroalkyl and Polyfluoroalkyl Substances—Version 2 (2024). This is the first update of the Agency’s original per- and polyfluoroalkyl substances (PFAS) destruction and disposal interim guidance released in December 2020.
Congress directed EPA to develop and publish interim guidance on PFAS destruction and disposal (D&D) in Section 7361 of the Fiscal Year 2020 National Defense Authorization Act (NDAA). The guidance must address (though, is not limited to) certain PFAS-containing materials specifically listed in the NDAA, such as aqueous film-forming foam, soil and biosolids, textiles, spent filters, and landfill leachate. The guidance must also address the potential for PFAS releases during destruction and disposal, including providing testing and monitoring guidance, and consider potentially impacted vulnerable populations. The NDAA requires EPA to update the guidance as appropriate, but at least once every three years.
In both versions of the D&D interim guidance, EPA evaluates the best available science to present to managers of PFAS waste considerations for determining which of the currently available destruction, disposal, or storage options best suits the waste in question. In the 2024 D&D guidance update, EPA retains the three technologies highlighted in the 2020 guidance: underground injection, landfilling, and thermal treatment. The Agency also offers interim storage as a short-term waste management option, and encourages waste managers to select the D&D option with the lowest potential for PFAS releases to the environment. The most appropriate option will depend on the type of waste, and EPA discusses these applicable considerations for each of the methods included.
Underground Injection
Underground injection is a disposal method for fluids that involves injecting the fluid underground via a well and is regulated primarily under the Safe Drinking Water Act (SDWA). The underground injection control (UIC) program address six different classes of UIC wells, depending on the type and depth of injection and potential impacts to underground sources of drinking water.
In the context of PFAS disposal, EPA has identified Class I non-hazardous industrial waste and hazardous waste wells as a disposal option for liquids containing high concentrations of PFAS. This disposal method is expected to have relatively low potential for PFAS releases into the environment compared to other methods. Hazardous waste wells, in particular, are regulated under both SDWA and the Resource Conservation and Recovery Act and are subject to more stringent requirements.
Landfills
Landfilling remains on the list as a method for disposal of PFAS and PFAS-containing materials. However, due to new data and a better understanding of the potential for PFAS releases from landfills, EPA recommends sending certain PFAS and PFAS-containing materials to a hazardous waste landfill, particularly where PFAS concentrations in the waste are high. The guidance specifically discusses certain categories of PFAS compounds and waste types as being more or less suitable for disposal in a landfill, depending on chemical characteristics (e.g., likelihood to migrate, biodegrade, or generate gas).
Thermal Treatment
Thermal treatment remains a viable PFAS D&D method in the 2024 guidance update. Unlike underground injection and landfilling, thermal treatment (when performed under certain conditions and depending on the type of waste/PFAS compound) is a PFAS destruction, rather than disposal, option. Thermal treatment options include commercial incinerators, cement kilns, lightweight aggregate kilns, and granular activated carbon reactivation units with thermal oxidizers. Like the other options EPA discusses, further information is needed to ensure that PFAS are not released into the environment in the treatment process. Of particular concern with thermal treatment are products of incomplete combustion (i.e., the compound breaks down partly, but not to full decomposition). Certain conditions, such as higher temperatures and longer residence times, may support more complete destruction. EPA recommends additional research, including in collaboration with EPA, to help address outstanding uncertainties.
Other key sections of the interim guidance include considerations for potentially vulnerable populations living near likely PFAS D&D sites, research needs and data gaps for D&D technologies, and emerging technologies. The section on emerging technologies includes a framework for evaluating new PFAS D&D technologies to assess their safety and efficacy.
EPA is accepting public comments on this guidance through October 15, 2024. Comments will inform the Agency’s next guidance update.