Abstract
Laboratory tests were done using a bespoke device to investigate landfill leachate seepage through a circular failed geocomposite liner. Pressures simulating actual landfill waste loads were applied to the lining system. The buffering capacity of a natural zeolitic mineral layer was investigated by measuring the leachate seepage rate and anionic (Cl and HCO3) contaminant transport through the geo-composite liner-buffering strata (BS). Simulated landfill waste loads from 25-150kPa were introduced to the system at intervals. The findings showed considerable reduction in seepage rate over the increased pressure. The seepage reduction is ascribed to the reduced liner transmissivity, θ and compressed soil layer. The natural zeolitic soil exhibited poor buffering of Cl ions but showed a fair
outcome in the case of HCO3 ions. Data for seepage rates were compared with predicted values from existing equations by Forchheimer and Giroud. The comparisons showed inapplicability to this study and to real life scenarios, if conditions of perfect contact at
the polyethylene/soil interface were assumed. Nonetheless, Giroud’s equation for good contact condition gave considerable seepage rate prediction through a failed geo-composite liner.