Equivalent analytical models for assessment of landfill composite liners

Abstract

An equivalent analytical model based on time moments is proposed to estimate the properties of landfill composite liners. The service performance of landfill liners composed of a geomembrane layer (GMBL), a geosynthetic clay layer (GCL), and an attenuation layer (AL) and a GMBL, compacted clay layer (CCL), and AL were equivalently analyzed. The equivalent analysis and quantitative correlation of contaminants at the bottom of the GMBL/GCL/AL and GMBL/CCL/AL systems were considered according to the relative concentration (CN), instantaneous flux (JI) and accumulative flux (JA). The relative concentration (CN) was found to be the most conservative equivalent index. The thickness equivalent relation of the AL for the different composite liners was consequently obtained using the pure diffusion equivalent model and the advection–diffusion equivalent model. It was found that the pure diffusion thickness equivalent relationship was a simplified linear correlation and independent of time. The quadratic polynomial equivalent equations of AL thickness for different service times were obtained by the group method of data handling. The results showed that GCL-based composite liner had a better environmental protection performance than the CCL-based composite liner. When the thickness of the GMBL/CCL/AL composite liner was fixed, the corresponding equivalent thickness of AL in the GMBL/GCL/AL composite liner decreased with an increase in the leachate head and the wrinkle length for the same value of CN.