EPA Research Partner Support Story: Removing PFAS from community drinking water with granular activated carbon

Partner: North Carolina Department of Environmental Quality, Cape Fear Public Utility Authority
Challenge: Removing PFAS from community drinking water with granular activated carbon 
Project Period: 2017 ‒ 2021

The Cape Fear Public Utility Authority (CFPUA) reached out to EPA ORD for help with plans to reduce PFAS from the community drinking water system, particularly with technical support for modeling pilot scale data. The partnership kicked off with a preliminary meeting held in Wilmington, NC with EPA Region 4 and the North Carolina Department of Environmental Quality. Since then, the partnership has led to a series of collaborative projects over several years. During this time, ORD researchers used data from two different long-term granular activated carbon (GAC) piloting exercises over multiple seasons. The pilot-scale data were fitted for 16 PFAS species and five commercial activated carbons using an EPA open-source pore and surface diffusion model that includes an automated parameter-fitting tool.

“EPA research has been extremely helpful to us in planning the startup operation of our GAC facility to reduce influent PFAS levels and meet various treatment goals. The Cape Fear Public Utility Authority (CFPUA) appreciates our partnership with EPA ORD in Cincinnati on the modeling of the GAC performance…it was very beneficial for our project and in communicating how our GAC facility will perform relative to EPA’s proposed drinking water health advisories for PFAS." – CFPUA Deputy Executive Director Carel Vandermeyden

EPA’s GAC model was then used to predict treatment effectiveness for different scenarios of interest to the utility. These included: how a particular full-scale design could handle fluctuating PFAS concentrations; how increased water demand or potential changes in prescribed treatment goals would affect treatment; and how different pretreatments or GAC choices might impact treatment effectiveness. The modeling also evaluated the optimal number of GAC contactors and their sizes. For all these analyses, uncertainty analyses were completed. Ultimately, what was learned supported the utility’s decision to choose activated carbon and led to affordable, timely design and operational decisions that helped address the challenge of removing PFAS from the community drinking water system.