Reduction of anionic chemical contaminant infusion through engineered clayey medium

Waste containment has always involved the use of land which sees the disposal of enormous quantities of waste in landfills. This waste disposal approach creates gases and other toxic substances whose escape from containment facilities poses severe threats to environmental and human health. Most breakaways of toxic elements from landfills are often associated with leachate infusion through failed barrier components/ containment materials to levels with consequential impacts. As such, it is pertinent that barrier lining systems are designed and constructed with integrity to ensure the protection of soil, water resources and other natural reserves, as well as prevent the pollution of surrounding environment. These challenges paved way for the study to investigate landfill leachate infusion through a circular failed geocomposite liner using a laboratory fabricated permeation testing apparatus. Pressures which simulated actual landfill waste loads were applied to the lining system and the buffering capacity of a natural zeolitic mineral layer was investigated by measuring the leachate infusion rate and anionic (Cl and HCO₃) contaminant infusion through the geocomposite liner-buffering strata (BS). 25 - 150 kPa of simulated landfill waste loads were imposed on the system at intervals. The study was also done as a revalidation mechanism to previous studies. The outcomes revealed significant reduction in infusion rate over the varied pressure. The infusion reduction is attributed to the reduced liner transmissivity, θ and compressed soil layer. However, the natural zeolitic soil displayed poor buffering of Cl ions but showed a fair result in the case of HCO₃ ions. Data for infusion rates were compared with empirical values from existing models by Forchheimer and Giroud. The comparisons indicated inapplicability to this study and to real life scenarios if conditions of perfect contact at the polyethylene/soil interface were assumed. Nevertheless, Giroud's model for good contact condition considerably predicted infusion rate through a failed medium.