<< Click to Display Table of Contents >> Navigation:  Appendix A Examples > Example 19: Multiphase Diffusion Test > Description

In this example a multiphase diffusion test performed by Buss et al. (1995) is modelled. This test involved the migration of toluene from a ‘constant’ source through a 0.1 cm thick HDPE geomembrane, a 18.2 cm thick airspace and into a 12.3 cm water reservoir (assumed to be well mixed). Based on Buss et al. the geomembrane diffusion coefficient was 6 x 10-8 cm2/s and the phase coefficient was 43.8. From Schwarzenbach et al. (1993), the diffusion coefficient and phase coefficient for toluene in air are 0.088 cm2/s and 0.27 respectively. Based on these parameters the test is modelled for 600 hours and the calculated and observed concentrations in the receptor are provided at the end of this example.