When unacceptable levels of aqueous film-forming foam containing PFAS were impacting off-base drinking water , Weston, as part of a JV deployed within 72 hours to perform a time-sensitive assessment of three former burn pits consistent at the 3,750-acre Shaw Air Force Base in Sumter, SC. Focusing on the extent of contamination, the site characterization included a data gap analysis; surface, subsurface, and groundwater multimedia sampling; soil and groundwater remediation system design; and an on-site treatability study of soil involving granular activated carbon and ion exchange media in accordance with CERCLA protocols and in advance of federally enforceable PFAS standards.
Over a five-month period, more than 300 soil/groundwater samples were collected, which were submitted to federal- and state-accredited laboratories. Results indicated PFAS concentrations in multimedia significantly exceeded health-based screening levels, warranting treatment to mitigate potential threats to public health. As a result, the team delivered a draft version of the streamlined Interim Remedial Action Proposed Plan within 60 days, considerably faster than the traditional 6- to 7-month timeline for this deliverable. We presented and evaluated four alternatives in the proposed plan to treat 105,000 cubic yards of PFAS-impacted soil and groundwater. Our team has investigated 245 residential and business properties.
We designed and are now preparing to implement the remedy, which includes excavation, soil washing, and backfilling of treated soil, as well as extraction, treatment, and reinjection of treated groundwater. Once commissioned, these systems will support plume remediation and reduce downgradient migration of PFAS migration, saving the client long-term liabilities and protecting the nearby community from contamination.