EPA Research Partner Support Story: Optimizing the Operation of a full-scale PFAS Treatment Facility

Partners: North Carolina Department of Environmental Quality; Cape Fear Public Utility Authority (CFPUA)
Challenge: Optimizing the operation of a full-scale PFAS treatment facility
Resources: Sampling current full-scale drinking water facility and providing modeling support
Project Period: 2023 ‒ 2025

The Cape Fear Public Utility Authority (CFPUA) in Wilmington, North Carolina, has been dealing with PFAS contamination since it was discovered in the source water in 2017. To find viable solutions to treat PFAS, CFPUA completed two long-term piloting efforts. During these pilots, EPA researchers worked with CFPUA to model data and examine the implications of changing the utility’s full-scale design and future operational factors, including the number of beds, bed dimensions, startup times, influent concentrations, and flow rates. The results of this work were published in 2022: Modeling PFAS Removal Using Granular Activated Carbon for Full-Scale System Design.

“The communication from the EPA team has been great and the process is well organized. The sampling schedule has been reasonable, and the EPA group has been accommodating whenever we needed to adjust the schedule due to holidays. Communication and delivery of kits has been seamless. The process from the operational standpoint is smooth. I can see that the data is useful and has value.” – CFPUA Water Resources Manager Ben Kearns

While these pilot efforts were underway, CFPUA constructed a full-scale granular activated carbon (GAC) facility at the Sweeney Water Treatment Plant that started operation in late 2022. Ongoing sampling shows that the GAC system can remove the PFAS that are currently regulated or proposed for regulation. CFPUA has also pursued efforts to optimize the operation of its facility to treat PFAS associated with a noted upstream discharger as indicated in a judicial order.

As part of the technical assistance provided by EPA’s Office of Research and Development, EPA implemented a long-term biweekly sampling program starting in February 2024 at the full-scale GAC facility. This program includes sampling from the raw water intake and distribution system entry point. Intensive sampling is performed around the GAC contactors at the influent, effluent, and numerous points throughout the carbon bed. The goal is to generate a dataset that can support modeling efforts aimed at helping the utility optimize its GAC technology while meeting effluent water quality goals.

Preliminary results show how one utility’s source water—in this case, the Cape Fear River—can pose a challenge due to changes in PFAS concentrations and water quality. These results will give CFPUA science-based information on how to optimize the operation of their system.