PFAS Removal and Phased Construction of Existing Treatment Facility
It was discovered that the groundwater wells that supply drinking water to Pease International Tradeport in Portsmouth were impacted by per- and polyfluoroalkyl substances (PFAS). PFAS are a family of thousands of man-made compounds that are potential hazards to human and ecological health. The City of Portsmouth selected Weston & Sampson to provide assistance on multiple fronts as they addressed the impacts of PFAS at the site, which is located at the former Pease Air Force Base and listed on the US EPA’s National Priorities List (NPL).
Weston & Sampson conducted and reviewed a groundwater monitoring program to help delineate the sources of PFAS contamination to better aid in the design of an aquifer remediation system. Working as a partner with the city, our interdisciplinary team of engineers, scientists, and construction specialists designed and installed temporary granular activated carbon (GAC) treatment to remove lower concentration PFAS levels from two of the wells. We then assisted the city by designing upgrades to the existing treatment facility, including 3,800 square feet of space to house ion exchange resin and GAC filters, along with a new control room and supervisory control and data acquisition (SCADA) system. Other system appurtenances include a raw water booster pump skid, chemical feed systems, a backwash water recycle system, HVAC, plumbing, and an emergency generator. Additional improvements include refurbishment of well stations with new instrumentation, new vertical turbine well pumps, and variable frequency drives. The new permanent treatment system is designed to treat 1,200 gpm from the three wells.
Finally, we provided construction oversight services for the new Pease Water Treatment Facility. Construction required carefully sequencing in order to keep the existing system operational and minimize the number of system shutdowns. Construction of the permanent system took just over two years, and several Weston & Sampson personnel were on hand for the formal dedication of the new state-of-the-practice treatment facility held at the Pease International Tradeport.
Key Project Features:
- per-and poly-fluoroalkyl substances (PFAS) removal
- ion exchange resin and granular activated carbon pressure filtration system
- backwash water recovery
- phased construction around an existing treatment facility