Commercial airports worldwide have used aqueous film-forming foam (AFFF) for aircraft rescue and firefighting (ARFF) training and emergency response operations for decades. AFFF formulations contain PFAS at concentrations of 1–3% by weight, and a single training exercise can release hundreds of liters of foam concentrate. Cumulative releases over decades have resulted in groundwater contamination at many airports at concentrations reaching thousands of parts per trillion—far exceeding EPA’s 4 ppt MCLs for PFOA and PFOS and affecting municipal water supplies, private wells, and surface water features adjacent to airport property.
Magnitude of Airport PFAS Contamination
Airport PFAS plumes are among the most concentrated and extensive PFAS contamination scenarios encountered outside of direct fluorochemical manufacturing sites. Groundwater monitoring at major international airports has detected PFOS and PFOA at concentrations exceeding 10,000 ppt (10 ppb) within the immediate footprint of ARFF training areas, with plumes extending kilometers downgradient. Denver International, O’Hare, and dozens of regional airports have active site investigations or remediation programs driven by state and federal regulatory pressure.
AFFF contamination is particularly challenging to remediate because decades of repeated small releases have deeply infiltrated vadose zone soils, creating a sustained source of PFAS leaching to groundwater that persists long after foam use is discontinued. Soil flushing, thermal treatment, and in situ chemical oxidation have all been piloted at airport sites with varying degrees of success in reducing source zone mass flux.
Treatment System Design for Airport Runoff and Groundwater
Interim containment and treatment systems at airports typically combine pump-and-treat groundwater extraction with above-ground treatment using GAC or single-use ion exchange resin. GAC systems are cost-effective for high-volume applications but require frequent regeneration or replacement when treating PFAS-laden airport groundwater, particularly in the presence of competing natural organic matter. High-pressure membrane systems (nanofiltration, RO) are used at some airports to generate a clean permeate for discharge while concentrating PFAS into a manageable brine or reject stream for off-site destruction.
Permanent stormwater management upgrades are a critical element of long-term airport PFAS management. Modern ARFF training facilities are being redesigned with closed-loop drainage systems that capture all foam-containing runoff for treatment and recycle rather than discharge. Transition to fluorine-free foam for non-emergency training exercises—a regulatory requirement in the EU since 2022 under the PFAS restriction under REACH Annex XVII—is underway at major European airports and increasingly at U.S. facilities under FAA guidance.