Source removal combined with drinking water treatment of a PFAS-contaminated groundwater

The United States Air Force Civil Engineering Center (AFCEC) has conducted response activities to remove and remediate groundwater impacted by poly- and perfluoroalkyl substances (PFAS) at the former Pease Air Force Base in New Hampshire. The two primary PFAS compounds found at the source area, a former fire training area (FTA), were perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) at combined concentrations (PFOA+PFOS) above the United States Environmental Protection Agency's (USEPA) Health Advisory Level (HAL) of 0.07 micrograms per liter (µg/l). AFCEC responded by contracting with Wood Group PLC to conduct a side-by-side pilot test in 2016, comparing the performance of Emerging Compound Treatment Technology's (ECT2) regenerable ion exchange (IX) resin and bituminous granular activated carbon (GAC). The regenerable resin system was selected for full-scale application, based on system performance and a lower overall lifecycle cost than GAC. Similar work was conducted in parallel on drinking water supply wells for the City of Portsmouth, New Hampshire which are also affected by contamination from the Pease Air Force Base. The City wanted to run long-term PFAS treatability testing on the heavily contaminated Haven Well but were not able to run the tests at full scale. A side-by-side pilot test was conducted to compare the effectiveness of ECT2's single-use SORBIX LC1 IX resin versus Calgon's F400 GAC. The objectives of the test were to: compare the ability of ECT's Sorbix LC1 IX resin and Calgon's F400 GAC to remove PFAS from the Haven well; compare system sizing and design parameters to be used in the preparation of the fullscale treatment system technology evaluation; and select the best PFAS-removal technology for full-scale implementation, based on lifecycle cost comparison and risk considerations. (author)