Surface water utilities face a significant challenge as they prepare to meet regulations for PFAS. While adsorptive media technologies such as granular activated carbon (GAC) and ion exchange (IX) resin are among the most established and cost-effective PFAS treatment solutions, their application in surface waters are complicated by natural organic matter, metals, and other constituents that reduce treatment efficiency, increase fouling potential, and create operational challenges.
To evaluate strategies for overcoming these limitations, we carried out a PFAS pilot study in partnership with the Charles Allen Water Treatment Plant. Previous testing at this site demonstrated that single-media adsorption systems experienced significant fouling and hydraulic instability, preventing sustainable long-term operation. Building on these findings, the pilot investigated whether mixed-media treatment trains could improve performance and operational reliability. By combining media types, we hypothesized that the strengths of individual media could be leveraged while mitigating their limitations. Iron and manganese pretreatment was also incorporated upstream of the adsorption columns to reduce fouling potential and improve overall system performance. Throughout the study, PFAS removal efficiency, hydraulic behavior, backwash requirements, and changing source water conditions were closely monitored.
Shifting water conditions and changes in plant operations created a valuable opportunity to assess how well the mixed-media approach could perform under real-world variability. The results showed improved hydraulic stability, lower backwash demand, and more consistent performance than single-media approaches previously tested at the site.
This work advances a more adaptable and operationally practical approach to PFAS treatment for surface water utilities. The findings demonstrate that mixed-media adsorption systems can improve reliability and resiliency while reducing operational burdens, helping utilities make informed treatment decisions and expand the viability of adsorptive PFAS removal for challenging water sources.
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