Breakthrough time assessment of liner system for MSW landfills with high leachate heads

This paper presents a design method for liner systems of municipal solid waste (MSW) landfills with high leachate heads based on the breakthrough time of an indicative contaminant (Chloride). The performance of liner systems with varying thicknesses of compacted clay liner and attenuation layer was assessed. The single composite liner consisting of a geomembrane and a 0.75-thickness compacted clay liner can meet the 50-year breakthrough time requirement of the liner system for cases with the thickness of the attenuation layer > 3m and the average height of waste H-D < 60 m. The double liner system consisting of two geomembranes with one single 0.3m-thickness compacted clay liner, as proposed in the Chinese landfill standards, cannot meet the 50-year breakthrough time requirement of the liner system, especially for large-scale landfills (e.g., H-D > 60 m). The double composite liner with two composite liners consisting of a geomembrane and a 0.3m-thickness compacted clay liner can be used for a landfill with an average height of over 60 m. Different liner systems for other cases with different average design heights of waste and the thickness of the attenuation layer were proposed. They can be easily used for MSW landfills with high leachate heads.