In order to understand the one-dimensional transient transport process of organic contaminants in a triple-layer composite liner composed of geomembrane (GMB)

geosynthetic clay liner (GCL) and compacted clay liner (CCL) under the non-isothermal distribution condition

the factors such as advection

diffusion

mechanical dispersion

adsorption

degradation and thermal diffusion are considered

and the corresponding mathematical model is established

in which the variations of parameters such as diffusion coefficient and permeability coefficient with temperature are incorporated. The numerical solution for the proposed model is obtained by using the finite difference method. The correctness of the established model is verified by comparing the calculation results of the model with the experimental data

the calculation results of the existing analytical model and the numerical results of COMSOL software. Based on the defined breakthrough time t

toluene is adopted as a representative organic contaminant to analyze and discuss the influences of different factors on the transport behaviors. The results show that: (1) The non-isothermal distribution condition changes the parameters such as the permeability coefficient

the diffusion coefficient and the linear adsorption coefficient. The variations of the permeability coefficient and the diffusion coefficient accelerate the transport process

especially for the diffusion coefficient

while the variation of the linear adsorption coefficient slows down the transport rate. (2) The increase of the temperature difference ΔT between the upper and bottom of the composite liner reduces the breakthrough time t and increases the bottom transport flux Jb. When Δ values are 0

10

20

30 and 40 K

the corresponding tb values are 65.7

58.5

54.3

52.0 and 51.2 years

respectively. (3) When the diffusion coefficient of GMB changes from 3.0×10 m2/s to 3.0×10 m2/s

the effect of Dm

R on is obvious. It is found that the existence of GCL has a little effect on the transport behaviors by comparing in the two cases.