U.S. EPA’s Updated 2024 Interim Guidance on the Destruction and Disposal of PFAS

On April 8, 2024, the U.S. Environmental Protection Agency (U.S. EPA) issued an updated interim guidance for public comment on the destruction and disposal of per and polyfluoroalkyl substances (PFAS) and PFAS-containing materials.

U.S. EPA published the first edition of this guidance in December 2020 as required by the National Defense Authorization Act for Fiscal Year 2020 (FY20 NDAA), which was previously covered by ALL4. The FY20 NDAA directed U.S. EPA to address the destruction and disposal of PFAS and specific PFAS-containing materials and requires U.S. EPA to review and update the guidance as appropriate, but no less frequently than every three years. The six PFAS-containing materials covered under this guidance are:

1 ) Aqueous film-forming foam (AFFF)

2) Soil and biosolids

3) Textiles, other than consumer goods, treated with PFAS

4) Spent filters, membranes, resins, granular carbon, and waste from water treatment

5) Landfill leachate containing PFAS

6) Solid, liquid, or gas waste streams containing PFAS from facilities manufacturing or using PFAS

The guidance includes destruction and disposal technologies from both existing, publicly available information, as well as research and development that is currently in progress. You can read the full 2024 updated interim guidance document here, but an overview of updates is below. Consistent with the 2020 guidance document, it is important to note that this guidance does not represent an enforceable rule or policy.

Interim Storage with Controls

U.S. EPA identified interim storage (two to five years) as an option in the 2020 guidance document for scenarios where immediate destruction or disposal is not imperative. In the 2024 guidance document, interim storage is still provided as a short-term option, however U.S. EPA has added that proper controls must be in place to reduce release and recommends that this option only be utilized for low volumes of containerized or high-concentration materials. Interim storage is not a suitable option for continuously generated materials.

Underground Injection – Permitted Class I non-hazardous industrial or hazardous waste injection wells

Underground injection was identified as a long-standing, well-regulated disposal technology in the 2020 guidance document which is suitable for liquid PFAS wastes. This has not changed with the 2024 guidance document, and underground injection is identified as having a lower potential for environmental release when compared to other destruction and disposal options as these wells may help ensure that injected fluids are confined and cannot enter underground sources of drinking water.

However, a downside identified in 2020, which still exists in 2024, is the lack of commercial hazardous waste injection wells in the United States. The limited number of wells currently receiving off-site PFAS and waste transportation logistics may significantly limit the type and quantity of PFAS-containing fluids appropriate for underground injection, and result in higher costs.

Approximately 17 percent of Class I wells are hazardous waste disposal wells. Most Class I hazardous waste wells are located at industrial facilities and dispose of waste generated onsite. These wells are operated in 10 states with the majority in Texas and Louisiana. Only a few commercial Class I wells accept hazardous waste generated offsite. The Hazardous and Solid Waste Amendments (HSWA) to the Resource Conservation and Recovery Act (RCRA) added significant restrictions on the disposal of hazardous waste. Under these amendments, land disposal of hazardous wastes, which includes Class I hazardous waste injection wells, is prohibited unless the:

• Waste has been treated to become non-hazardous or;
• Disposer can demonstrate that the waste will remain where it has been placed for as long as it remains hazardous, which has been defined as 10,000 years by regulation.

Landfills

A key concern when considering landfills for PFAS disposal is the ability to minimize or mitigate PFAS migration, either through leachate or volatilization in landfill gas. This is especially a challenge given the variability in control requirements different landfills are subject to (e.g., hazardous waste landfills vs. municipal solid waste landfills). The 2024 guidance document provides more information regarding specific scenarios and landfill types that U.S. EPA recommends. For example, U.S. EPA recommends Subtitle C landfills when PFAS levels of the waste are relatively high, those of which lead to a hazardous waste leachate PFAS concentration range of up to 377,000 ng/L. This is because RCRA Subtitle C hazardous waste landfills have the most protective landfill engineering controls and practices for the containment of PFAS waste and would be more effective at minimizing PFAS release into the environment than other landfill types. Hazardous waste landfills also typically have relatively low quantities of landfill leachate, which also reduces risks of release.

Similarly, U.S. EPA states that non-RCRA Subtitle C landfills are only appropriate when disposing of stable polymeric PFAS, such as polytetrafluoroethylene (PTFE), because they are not susceptible to hydrolysis or oxidation, and they are neither volatile nor water soluble. Therefore, the risk of release through leachate or landfill gas is low, even if the landfill does not have the same level of controls as a hazardous waste landfill.

However, for all landfill types, current information demonstrates landfilling could have higher PFAS releases to the environment than previously thought in 2020, especially for soluble PFAS that are prone to migration.

Thermal Treatment

The technologies evaluated under thermal treatment are hazardous waste combustors, such as commercial incinerators, cement kilns, lightweight aggregate kilns, and thermal oxidizers, as well as granular activated carbon (GAC) reactivation units with off-gas incineration and gas scrubbing units. In general, due to the lack of limited research and full-scale test data, there is still uncertainty regarding the effectiveness of this technology and the formation of alternate forms of PFAS as products of incomplete combustion. However, U.S. EPA believes that operation at higher temperatures (>1,100°C), well mixed combustion environments, and longer residence times may be more conducive to destroying PFAS and controlling related products of incomplete combustion. Thermal treatment is still considered a viable option for PFAS destruction, but more testing is required.

Emerging Technologies

U.S. EPA conducted a study of the effectiveness of four emerging technologies for PFAS destruction:

1) Mechanochemical degradation

2) Electrochemical oxidation

3) Gasification and pyrolysis

4) Supercritical water oxidation

Although the 2024 guidance document notes that the evaluation of these emerging technologies should not be considered an endorsement or recommendation by U.S. EPA, these technologies all showed promise during the conducted pilot studies as they each exhibited PFAS destruction, minimal to no hazardous residuals or byproducts, commercially available, and can be cost-effective. Pilot studies were conducted using contaminated soil/sand, biosolids, and AFFF.

While there are still many unknowns regarding disposal and destruction techniques for PFAS, it is becoming more difficult to find locations willing and able to manage the waste. U.S. EPA did not contemplate additional demand to send PFAS off to Hazardous Waste facilities for disposal. The capacity assessment in 2019 said there is adequate capacity nationwide through 2044, and a new assessment is currently underway to incorporate new information and extend the time horizon. ALL4 is available to assist in the evaluation and strategy for disposing or treating of PFAS-containing materials at your site. If you have any questions, please contact me at xaguilar@all4inc.com or reach out to one of our project managers.