Summary

RemBind trialed injection delivery of its stabilization product into groundwater at a site adjacent to a major airport, as a proof of concept for treating PFAS in the saturated zone without excavation, testing both whether the product could be physically delivered by injection and whether it could reduce PFAS concentrations in-situ.

• RemBind® was injected via gridded points (~2 m spacing) around the highest-concentration monitoring well in a silty clay/fill treatment zone, where prior soil and groundwater sampling had found PFAS up to 4,500 ng/kg and 3,300 ng/l respectively.
• The team adjusted slurry dosing before injection after finding the initial design density too low, and observed radial distribution effects extending 7–10 m side-gradient (plus upgradient/downgradient movement), and a recommendation of a greater than 2 m initial injection interval in similar fill material.
• Slug testing showed hydraulic conductivity was higher than expected due to sandy heterogeneity, with combined average K values of 7.52 x 10⁻⁴ upgradient versus 3.15 x 10⁻⁴ in the injection area, indicating some but manageable effect on groundwater flow.
• Groundwater PFAS concentrations dropped substantially post-injection: combined PFHxS+PFOS fell from an initial 3,340 ng/l to 5 ng/l by 24 weeks, and total PFAS fell from 6,040 ng/l to 156 ng/l over the same period.
• Field parameters (pH, temperature, EC) were only minimally affected by the injection, and confirmatory direct push cores and multiple lines of evidence supported good product distribution through the treatment zone.
• The team concluded RemBind® is easily slurried and injected with minimal dust generation, distributes well, and produces reductions consistent with earlier soil treatment/column tests, though surfacing can occur at shallower injection intervals and appropriate injection equipment is needed.