AAAS EPI Center and GLLC Roundtables

Treatment and Mitigation of PFAS in Drinking Water | AAAS EPI Center

PAC can provide long-chain PFAS reduction , with higher PAC concentrations resulting in greater PFAS reduction 6 . PAC has been shown to be less effective at removing short-chain PFAS 6,7 . PFAS removal with PAC can vary greatly on a case-by-case basis and ranges from 40 to 80 percent removal. One benefit of using PAC is that PAC systems can be installed and integrated into existing WTPs relatively quickly. PAC can be added intermittently if occasional use is desired, such as to address seasonal fluctuations in certain contaminant levels. Additionally, some WTP already have PAC systems to remove additional contaminants such as TOC, color, taste and odor compounds, and thus are able to rapidly utilize PAC for PFAS reduction 5 . One challenge of PAC is that it may not effectively remove short-chain PFAS, and although it can remove additional contaminants, these contaminants will compete with PFAS for adsorption sites on the surface of PAC media. Therefore, the optimal PAC dose for PFAS removal may be uneconomically high. PAC also produce waste that requires disposal. After PAC has adsorbed PFAS, it is removed from water by other treatment processes and is disposed of with other solid wastes produced during water treatment. This poses two issues. First, the WTP will have to dispose of an increased amount of waste. Second, the waste now contains PFAS, which restricts where the waste can ultimately be disposed of. Depending on how the WTP manages the solid wastes, PAC waste may be conveyed to a wastewater treatment plant or landfill, which both pose challenges related to PFAS disposal and cycling of PFAS in the water system. Due to these challenges, PAC is recommended as a short-term solution for PFAS reduction. Compared to other PFAS treatment methods discussed in this guide, PAC is a treatment option with low capital and operating cost , but operating costs depend on the PAC dose applied.

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