Simulation of Leachate Movement from Clay Geosynthetic Liners Using a Laboratory Model

Landfilling is a widely used disposal of waste process that involves safely disposing of solid waste on land. Its main goals are to eliminate health and environmental risks, minimize disturbances, and prevent contamination of surface and underground water sources. The pollution of groundwater caused by the discharge of liquid waste from landfills poses a threat to all forms of life. The majority of landfill sites in developed nations have implemented geosynthetic clay liners (GCLs), which can be regarded as a purposefully designed solution to prevent the infiltration of harmful contaminants into groundwater. A geosynthetic clay liner (GCL) consists of two geotextiles that are needle-punched together, enclosing a layer of bentonite (with a mass per unit area of 3–5 kg/m²) between them. GCLs are renowned for their uniform and exceptionally low permeability. This article examines the impact of leachate obtained from the Isfahan landfill on the hydraulic and chemical characteristics of twelve clay geosynthetic liners. The twelve Geosynthetic clay liners utilized in this investigation exhibit variations in the bentonite type, connection technique (needle punched and adhesive), and the bentonite mass per unit area (4, 4.5, and 5 kg/m²). A device was constructed specifically for the purpose of quantifying the hydraulic conductivity of liners under elevated pressures. A device was constructed specifically for the purpose of quantifying the hydraulic conductivity of liners under elevated pressures. The findings indicate that the hydraulic conductivity of a geosynthetic clay liner (GCL) with an adhesive connection under a pressure of 40 kPa is greater than the hydraulic conductivity of a GCL with a needle punched connection at the same pressure. The leachate output was gathered daily, and the levels of cations (calcium, sodium, and potassium) as well as the pH were assessed. The interaction between the bentonite content and the penetrant leads to a cation exchange, resulting in a modification of the elemental quantities. Moreover, a higher pH ratio signifies the buffering capacity of bentonite.