NZ Geotechnical Society (NZGS) 22nd Symposium 2025 Auckland
Growing environmental concerns over per- and polyfluoroalkyl substances (PFAS), particularly short-chain compounds like perfluorobutanoic acid (PFBA) and perfluorobutane sulfonate (PFBS), have underscored the need for more efficient landfill liner barrier systems. This research evaluates the hydraulic performance of geosynthetic clay liners (GCLs) modified with carboxymethyl cellulose (CMC), a biopolymer used to enhance bentonite’s containment properties. Various CMC dosages were blended with bentonite to assess their effect on reducing hydraulic conductivity. Both untreated and optimally modified bentonite samples were then tested against synthetic leachates containing PFBA and PFBS using a flexible wall permeameter. The findings revealed that bentonite modified with 8% CMC exhibited the lowest hydraulic conductivity under both distilled water and PFAS leachate conditions. These results highlight the potential of CMC-treated bentonite as a reliable barrier material for controlling PFAS migration in landfills, supporting improved waste containment and groundwater protection.
