SUMMARY

As part of a proposed industrial development with PFAS-impacted soils, adjacent to sensitive waterways and ecological habitat, WSP designed and implemented a Permeable Sorption Barrier (PSB) using RemBind® to enable safe, beneficial reuse of contaminated soils without the need for removal or remediation.

• A weighted Multi-Criteria Analysis of six mitigation options identified the PSB as the preferred solution, scoring 18 against alternatives such as soil stabilisation (16), clean fill only (12), and above-ground encapsulation (6).
• Laboratory trials compared RemBind® against powdered activated carbon (PAC) and biochar, spiking soils with PFOS concentrations of 0.5–10 mg/kg. RemBind® reduced ASLP leachate from 32–744 µg/L (untreated) to just 0.5–21.5 µg/L, with MEP testing confirming stable, long-term binding.
• RemBind® demonstrated more reliable sorption than PAC, while biochar was not advanced beyond initial testing due to insufficient PFOS retention.
• The final design applied a 100 mm thick, 0.5% w/w RemBind® PSB across more than 1 million m³ of soil beneath the surcharge layer.
• Groundwater monitoring over 4.5 years showed no notable, unexpected, or statistically significant increase in PFOS concentrations, confirming the long-term performance of the barrier.
• The project demonstrates that PFAS-impacted soils don’t always require remediation or removal — engineered, risk-based controls can manage mobility and enable cost-effective, large-scale reuse.