Composite liner induction time

Data about the imperviousness of a faultless liner system under defined boundary conditions for as large a number of pollutants and soil materials as possible form an important component of the characterisation of the efficacy of this liner for instance in comparison to equivalent alternative liner systems. Therefore, in the following, a parameterization will be discussed for the permeation rate (or the permeability) and the induction time for diffusive mass transport in the composite liner consisting of a geomembrane and a compacted clay liner (or more generally a porous mineral material). Quantities, which refer to the geomembranes, will be denoted with index 1, such as thickness d and diffusion coefficient D, and quantities referring to the mineral liner will have index 2 such as thickness d2 and effective diffusion coefficient D2. The porosity of the water-saturated mineral liner is denoted with 0 as above. 

The formula for the induction time of the overall system can be calculated by the method of Laplace transformation, see (Carslaw and Jaeger 1959) and (Barrie et al. 1963). The induction time t of the composite liner is composed of induction times h and t2 and permeabilities P and P2 of the components as follows ... 

Fig. 7.3b. Calculation of the acetone mass diffusing through the composite liner (thickness of the mineral liner (ML) 30 cm) per m as a function of time. The slope of the straight line yields the permeation rate and its time axis intercept provides the induction time. The induction time is 1440 days and the permeation rate in a steady-state condition is 0.24 g/(m d) (Kalbe et al. 2000)...

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