Development of PFAS Pretreatment Programs: Challenges Faced by Landfills and Industrial Customers in the United States

Many industries discharge to municipal WWTPs rather than discharge directly to surface waters or groundwater. Municipal WWTPs are not known to have historically used materials containing significant quantities of PFAS; however, many receive wastewater from local industries via their Industrial Pretreatment Program (IPP). Some of those IPP permit holders, may have used PFAS-containing materials. Because PFAS are resistant to degradation and conventional treatment, they could have passed through most industrial pretreatment systems and made their way to the local WWTP, where they would be just as resistant to degradation and treatment and released to local receiving water via the WWTP's discharge. Similarly, WWTPs receiving landfill leachate could have unknowingly received PFAS. The presence of PFAS in some types of industrial wastewater and in landfill leachate was not known until relatively recently, so the process of WWTPs receiving and passing through PFAS could have been occurring for many years. Many states have required all municipal wastewater utilities with an IPP to identify potential industrial users that may be potential sources of PFAS, collect data on PFAS in their discharges, report the findings to the state, and develop plans to reduce the concentration of two PFAS compounds, PFOS and PFOA, in their effluent to meet state water quality standards. Minnesota's PFAS Initiatives with the updated IIP Program Minnesota's PFAS Blueprint, released in February 2021, provides more information about PFAS toxicity and their occurrence in Minnesota. In addition, it lays out the state's approach to managing and addressing PFAS. Across the topics covered by the PFAS Blueprint, themes emerge among the needed actions. These include: 1. Pollution prevention, 2. Investigation of PFAS discharges, 3. Environmental monitoring, 4. Toxicity research, 5. Regulatory development
Goals and objectives for PFAS monitoring
The goals of the monitoring plan are: 1. Gather Minnesota-specific information in order to craft effective policies around PFAS and their incorporation into MPCA programs; 2. Identify areas of particular concern (due to PFAS concentrations or routes of exposure) that need quick action; and 3. Gather data that galvanizes support for PFAS source reduction and pollution prevention.
How frequently will monitoring occur? Levels of PFAS in various media can change depending on the time of year, the weather, the activities occurring at industrial facilities, and other variables. PFAS monitoring and reporting requests will generally be aligned with existing monitoring and reporting that facilities already conduct for other pollutants. Aligning PFAS monitoring with other required monitoring and reporting will be efficient for both MPCA and permittees. The monitoring data will be used to support the three main goals articulated above.
Michigan's IPP PFAS Initiative To address the potential that municipal WWTPs could be passing through elevated levels of PFAS through their treatment systems to lakes, streams, and groundwater, EGLE launched the IPP PFAS Initiative in February 2018. The IPP PFAS Initiative required all municipal WWTPs with required IPPs (95 statewide) to find out if they were passing through PFOS and/or PFOA to surface waters or groundwater and, if found, to reduce and eliminate any sources. Under the Initiative, WWTPs were required to: - Identify industrial users to their system that were potential sources of PFAS. - Sample probable sources and their WWTP discharge (effluent) if sources were above screening criteria (12 ppt PFOS). - Require source reduction at confirmed sources. This is being accomplished through pollutant minimization plans, equipment/tank change out/clean outs, product replacement, and installation of pretreatment to remove PFAS, specifically PFOS, prior to discharge. - Monitor compliance of confirmed sources and ensure that they meet local IPP PFAS requirements. - Submit required reports and monitoring results as required by the WRD. Table 1 shows Sources of PFOS to WWTPs in Michigan. Landfill leachate Landfill leachate poses further consideration, as constituent concentrations of the various emerging contaminants range from low ng/L levels to tens of thousands of times that level. PFAS data on landfill leachate, WWTP influent, effluent, and biosolids within Michigan were analyzed to identify chemical signatures in landfill leachates and WWTP influent, effluent, and biosolids/sludges. Landfill leachates show diverse PFAS chemical signatures dominated by C-4s, C6s and C8s. Numerous transformations of undetected polyfluorinated precursors in the influent during the wastewater treatment process to more terminal perfluorinated compounds that are detectable in the effluent yield PFAS concentrations in the effluent that are 2-10 times greater than in the influent. A summary chart of average concentrations of the 5 Regulated PFAS at VT landfills is illustrated in Figure 1.
Summary
If your utility has an industrial pretreatment program, it may be a good idea to develop a PFAS strategy and share the concerns with your industrial users. As a first step, before sampling is required, it would be beneficial to have industrial users review their existing processes and raw products to determine whether there is a likelihood of PFAS present. Maintaining a collaborative relationship between your utility and your industrial users will help to identify ways to minimize, reduce, and eliminate PFAS from the industrial stream with product substitution and/or additional operational controls. To completely treat PFAS some of the innovative destruction technologies will be reviewed including:
- Modified bentonite adsorbents -
Foam Fractionation - Supercritical Water Oxidation -
Low-Temperature Plasma
These technologies are in their infancy and have shown significant promise. However, there still are concerns about residuals management, complete destruction, or sequestering short-chain PFAS. Additional evaluation on treatment processes is also needed to address concerns about treatment results where PFAS precursors become regulated PFAS constituents.