Analytical Model of Organic Contaminant Dynamics in Landfill Liners Subjected to Thermal Gradients

Predicting contaminant transport through landfill liners is crucial for evaluating groundwater pollution risks. This study proposes an analytical model of organic contaminants transport through various landfill liner systems considering the effects of diffusion, thermal diffusion, degradation, and advection under nonisothermal conditions. The influence of leachate head (hw), half-life of organic contaminants in the compacted clay liner (CCL), or attenuation layer (AL) (t1/2 or ta1/2), and length and width of wrinkles (Lw and 2b) on the service performance of the different landfill liner systems was conducted by Monte Carlo method. The results show that, increasing t1/2 from 10 to 50 years causes the 100-year bottom concentration of the single CCL liner to increase by a factor of 47.32. An increase in Lw from 100 m to 1,000 m results in a 3.15-fold increase for the geomembrane (GMB)/geosynthetic clay liner (GCL)/AL and a 1.6-fold increase for the GMB/CCL in the 100-year bottom concentration, respectively. The service lives of the CCL, GMB/CCL, and GMB/GCL/AL range from 29.5–135.5, 2.23–19.4, and 12.75–42 years, respectively. Increasing hw from 0.1 to 10 m causes the service life of the CCL, GMB/CCL, and GMB/GCL/AL systems to decrease from 135.5 to 29.5 years, 17.8 to 2.23 years, and 29.9 to 12.75 years, respectively. A low leachate head is fundamental to preserving the containment function of liner systems over extended periods.