Field-scale pilot studies for the in situ treatment of soils at PFAS source zones were recently completed at firefighting training areas on two aviation sites where PFAS-containing AFFF (i.e., aqueous film-forming foam) was historically discharged. The PFAS source treatments applied site-specific amendment blends of SourceStop™ colloidal activated carbon (CAC) and powdered activated carbon (PAC). SourceStop, a micron-scale aqueous carbon suspension, was emplaced as a horizontal PFAS barrier at the base of the target treatment zones. As published in a previous Remediation Technologyarticle, laboratory studies have shown that SourceStop prevents PFAS leaching with >10x more effectiveness than PAC.
Both pilot tests demonstrated PFAS soil leachate concentrations were reduced by >99% within hours following the source zone treatments and at one of the sites, six-month post-treatment monitoring results showed reduction to non-detect levels. Post-application sampling is planned for the second site, with similar results anticipated.