05 Aug Community Chat Now Available Online – The Science Behind Removing PFAS from Drinking Water
OWASA’s second PFAS Community Chat – Safeguarding Our Water: PFAS Q&A – focused on the science behind removing PFAS from drinking water. Video of the event is now available on our YouTube channel. Held at Lanza’s Cafe in Carrboro, this event connected environmental scientists and engineers at the forefront of PFAS removal technology research with members of the community.
Panelists:
- Orlando Coronell, Associate Professor, UNC Department of Environmental Sciences and Engineering
- Jeff Thompson, Project Manager for OWASA’s PFAS Pilot Project, Black and Veatch
- Allison Spinelli, Engineering Manager for Capital Projects, OWASA
Summary:
The second in OWASA’s series of PFAS Community Chats focused on the science and technology behind PFAS removal, specifically the methods OWASA is currently pilot testing and the direction of PFAS removal research. OWASA’s Engineering Manager for Capital Projects, Allison Spinelli, discussed how OWASA has been working with engineering firm Black & Veatch on a pilot project at the Jones Ferry Road Water Treatment Plant to identify the most effective PFAS removal technique for our water. OWASA is currently pilot testing two methods -Granular Activated Carbon (GAC) and Ion Exchange (IX).
Jeff Thompson, the project manager for OWASA’s PFAS pilot project, expanded on the pilot project to describe the different methods we’re testing. Thompson explained how PFAS treatment falls under two categories: adsorption and separation. Adsorption is when the contaminant sticks to the media or material used in the treatment. Separation is when a membrane or barrier separates the contaminant from the water. Both GAC and IX are adsorption techniques.
As shown in the visual below, GAC has pores or pockets (kind of like a golf ball) that PFAS compounds stick inside. GAC can be regenerated and used again, which is more cost effective then replacing the GAC. IX uses resin that is positively charged, which attracts the negatively charged PFAS molecules in the water causing them to stick together. There are currently no regenerative capabilities for IX, which means the resin must be destroyed after its lifecycle and replaced.
Orlando Coronell, associate professor at the UNC Department of Environmental Sciences and Engineering, and co-project leader of the NC Pure Project, discussed how PFAS removal research is currently trying to answer three main questions:
- How do we increase the capacity of sorbents (materials used for absorption), so they can remove more PFAS?
- How do we increase the selectivity of sorbents, so they exclusively remove PFAS instead of other substances?
- How can we improve the regenerative capability of sorbents and make regeneration more accessible?
Coronell also emphasized that there is a separate field of PFAS research working to identify ways to destroy PFAS completely, but those solutions are likely decades away. The NC Pure Project is working to make current PFAS treatment techniques more effective, affordable, and accessible.
The goal of OWASA’s PFAS pilot project is to determine which treatment technology – GAC, IX, or a combination – is most effective at removing the PFAS compounds we’ve detected in our source water at Cane Creek Reservoir, while continuing to provide high quality water to our community. The pilot project will also help us determine operational costs over time and how our water responds to PFAS treatment throughout the year.
OWASA’s pilot project began in February 2024 and is expected to last 18 months, after which OWASA will begin construction of the new PFAS treatment facility on our Jones Ferry Road Water Treatment Plant campus. The PFAS treatment facility will be in operation by 2029.