Application of Thermal Insulation in Landfill Liners

Until recently the temperature of landfill liners and its effects on the service-life of composite liners have received relatively little attention. However, there is growing evidence that the temperature may be sufficient to significantly reduce the service-life of the liner components, in particular that of the high-density polyethylene geomembrane. This paper presents a numerical study of the use of expanded polystyrene (EPS) geofoam and shredded tires as thermal insulators between primary and secondary liners. The temperature level on the secondary geomembrane is shown to be lower than the case without thermal insulation. Accordingly, the service-life is longer. The paper also highlights some of the challenges that would be associated with the potential use of geofoam or shredded tires and suggests that while using geofoam or shredded tires warrants consideration, much care would be required in the detailed design and construction of the liner.