Sr. Principal Scientist, Sr. Project Manager, Practice Area Leader
Amec Foster Wheeler
Nathan Hagelin is the Practice Area Leader for Environmental Remediation at Amec Foster Wheeler Environment and Infrastructure working out of Portland, Maine. He is a Certified Geologist and Licensed Environmental Professional with a focus on the remediation of contaminated industrial properties. Recently, he has been immersed in the emerging contaminant class, PFAS, including research and development of a treatment technology that will be the focus of his talk today.
PLATFORM PRESENTER - Emerging Contaminants: Tick Tock
Sustainable Removal of Poly- and Perfluorinated Alkyl Substances (PFASs) from Groundwater Using Synthetic Media
Polyfluorinated and perfluorinated alkyl substances (PFAS) are emerging as high-priority and high-profile contaminants. PFAS contamination is widespread, and many communities need large scale treatment systems to treat drinking water supplies for PFAS. However, PFAS are highly water soluble, have low volatility, and are difficult to treat. Granular activated carbon (GAC) effectively adsorbs long-chain PFAS compounds from water, but shorter-chain and branched PFAS have been shown to quickly break through GAC. Carbon change-outs require either virgin media or off-site regeneration and limit the sustainability of this technology. Synthetic media (ion-exchange resin) technology has shown significant promise for treating a broad suite of PFAS. Synthetic media can be regenerated on-site and reused, showing potential for a more sustainable adsorption technology.
This presentation will describe the design and operation of PFAS treatability tests and an on-site pilot test using synthetic media to treat groundwater from the former Pease Air Force Base in Portsmouth, New Hampshire. Test objectives were to:
Demonstrate treatment performance and regeneration potential of various synthetic mediaComplete a pilot test comparing GAC and synthetic media at Pease; and Develop a design and cost estimate for two full-scale treatment systems at Pease. Approach/Activities.
PFAS isotherm testing of seven resins, including polymeric, carbonaceous and ion exchange resins, was performed on a synthetic water to screen them for PFAS removal capability. Subsequent bench-scale column testing of the top three resins was conducted using groundwater from Pease. Two promising resins removed all analyzed PFAS compounds and were regenerated. One ion exchange (IX) resin was selected for further treatability trials and retained for pilot testing at Pease. Identical systems were designed for both synthetic media and GAC at pilot scale to treat groundwater from Pease with total PFAS concentrations of approximately 100 µg/L. The pilot test was completed in May of 2016.
At bench scale, we identified one IX resin with excellent PFAS removal properties that could be fully regenerated and reused. At pilot scale, IX resin was found to be more efficient than GAC at removing most PFAS and in particular PFSAs. Regeneration methods using a solvent-brine solution were optimized at pilot scale and fully restored PFAS removal capacity. Evaluation suggests IX is effective at PFAS removal by both ion exchange and adsorption mechanisms. Lifecycle cost analysis indicates IX resin has a 5 to 8 year payback compared to GAC, shorter for PFSA-dominated water.