Abstract
In a solid waste containment facility, volatile organic contaminants (VOCs) can diffuse through the geomembrane and have a potential to pollute the underlying soil and groundwater. A compacted clay liner (CCL) is frequently adopted as a barrier to the pollution plume. In this study, a theoretical model is developed to describe the effect of trapped gas bubbles on the transport of dissolved VOCs in a saturated CCL. The present model couples the consolidation of the liner due to waste emplacement and the solute transport of the VOCs. The numerical results suggest that the gas partitioning between the aqueous phase and a trapped gas phase can greatly reduce the rates of transport of hydrophobic VOCs in the CCL. However, the mitigation effect due to un-saturation and vapor sorption for the hydrophilic VOCs is less significant, compared with the hydrophobic VOCs. The bubble wall is a promising barrier to the hydrophobic VOCs. For the hydrophilic VOCs, the effects of retardation is anticipated if the biotransformation process occurs due to presence of oxygen in occluded bubbles, which can be produced by certain agent admixture. Moreover, the influence of varying gas bubble volumes on the VOCs transit time can be negligible.
Published Version
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