AECOM is evaluating PFAS impacts to a nearby river and storm water conveyance system at this military base. Due to past practices, AFFF entered the environment through accidental spills, pipe leaks, maintenance operations, storage and disposal, and extinguishing staged fires during fire training exercises. 25 potential release locations were identified during the Site Inspection.

Results of storm water monitoring points/outfalls sampling showed discharges from the sampled monitoring points contain PFOS, with reported results ranging from 33 to 2,400 ppt, well above the state standard of 11 ppt. Discharges from the five wet wells into a nearby river and lake have potential impact to human receptors since water from the lake is used for supplying drinking water to the community.

AECOM’s agency negotiations with regulators have been successful in developing a reasonable and cost-effective path forward. Our team successfully prepared and obtained approval of a Short-Term Storm Water Characterization Study Plan for PFAS and sampling began. AECOM’s team developed a phased approach in the evaluation and remediation of source zones. We conducted a dye test to evaluate the presence and location of a mixing zone of the storm water discharge points into the receiving bodies of water and potential impacts.

The team designed a storm water model/mitigation plan to evaluate PFAS loads within the storm water system under multiple base flow and storm flow management scenarios. The mitigation design evaluated possible options for upstream treatment of a much smaller volume of water. The team evaluated treatment methods such as granular activated carbon and ion exchange resins to deliver remedial designs that efficiently utilize treatment funding. The mitigation design also included recommendations of storm water conveyance system infrastructure repair and in-situ treatment of PFAS impacted groundwater.