The U.S. EPA recently released the 15th installment of its Preliminary Effluent Guidelines Program Plan[1]. In addition to announcing the initiation of new rulemakings for certain categories of industrial dischargers, the report provides a window into where the agency is focusing its attention for potential future clean water act regulations. This year, landfills were among the categories of sources that EPA has been studying, and will continue to study as it continues to look for ways of reducing per- and polyfluoroalkyl substances (PFAS) in the environment.

Previously received public comments about landfill leachate as a source of PFAS in surface water, groundwater, and publicly owned treatment works (POTWs) was identified as the impetus for this review. The agency’s study of landfills was also coordinated with a study of PFAS discharges from a broader range of industrial sources.

Primary Clean Water Act regulations for landfill leachate date back to 2000. At that time, although pretreatment standards for indirect discharges were initially proposed by the EPA Office of Water, the agency ultimately decided against enacting them because it concluded that “(1) raw leachate data were below published biological inhibition levels, and (2) other information indicated a lack of ‘pass-through’ of toxics (including lack of showing of adverse impact on POTW sludge quality).” 64 FR 6807[2]. Due to the rise of concern over PFAS, however, the agency may no longer feel the same way.

EPA’s recent review was based on previously published peer-reviewed literature and water sampling conducted by various states. The review did not reach any definitive conclusions about either the scope of the issue presented by PFAS in landfill wastewaters or how to address it. Rather, the agency concluded that “further research is needed to address limited data availability” and that it plans to proceed with a more “detailed study.” In particular, EPA is interested in gathering more information about the amount of wastewater indirectly discharged from landfills to POTWs, that wastewater’s impact on POTW influent and effluent PFAS concentrations, and whether there are landfills currently implementing PFAS treatment for leachate.

Given these areas of further inquiry and EPA’s current focus on all things PFAS, it appears that the agency is at least considering a leachate pretreatment requirement. Although the results of additional studies will likely further shape EPA’s thinking in this area, landfills may want to start contemplating how they would be affected by and deal with a PFAS-focused leachate pretreatment requirement.