Treatment of the mine’s water with GAC produced results that diverged meaningfully from pre-study modeling. Initial PFHxS breakthrough occurred at approximately 20,000 gallons — nearly three times the EPA model’s 7,000-gallon prediction. Had engineers designed a full-scale system based solely on the model, it would have been significantly oversized, inflating capital costs unnecessarily. This reinforced a core principle of WestLand’s approach: models provide a useful starting point, but pilot studies using site water allow engineers to capture the actual physio-chemistry occurring in the system enabling more appropriate full-scale design.
FS-200 demonstrated superior PFAS removal, with initial breakthrough at 50,000 bed volumes versus 20,000 for GAC — nearly twice the adsorptive capacity. Operational issues emerged during the study, including high pressure buildup, frequent backwashing, media clumping, and discoloration. Scanning electron microscopy and elemental analysis revealed accumulation of iron, barium, and magnesium, indicating site water chemistry was physically altering the media. Prefeasibility cost estimates nonetheless favor FS-200, at approximately $100,000 less than GAC for full-scale design. Detailed engineering will address the anomalies observed to ensure treatment effectiveness is not compromised.
The intermediate sampling port proved its value throughout: without it, breakthrough observation at the effluent alone could have extended the study beyond a year. With it, the team reached actionable conclusions in approximately six months — and the facility is now equipped with site-specific data to inform accurate system sizing, media replacement frequency, and lifecycle cost projections.
