Influence of antecedent moisture content on residual LNAPL saturation

In a water wet porous medium, the antecedent moisture content controls the entrapment of LNAPL at low capillary numbers. A two-phase retention cell study of entrapment was conducted for LNAPL water systems in a carbonate sand. For two different LNAPL water systems, if was found that a linear expression related the residual LNAPL saturation to the antecedent water saturation. The prediction of trapped LNAPL saturation compares favorably to long-column test data obtained for the same sand. A trapping model was developed, and its predictions were compared to field measurements of trapped LNAPL saturation. Deviations between predicted and measured LNAPL saturations arose when there was a change in the median pore size distribution. In addition, a series of three- phase (air- LNAPL-water) retention cell tests measured the amount of LNAPL that became trapped when the water phase was maintained at a constant saturation during LNAPL withdrawal under a negative pressure head. Under these conditions, the amount of trapped LNAPL was higher than that measured by two-phase tests at the same water saturation.

Published in:
Journal of Soil Contamination, 6, 2, 113-147

Note: The status of this file is: Involved Laboratories Only

 Record created 2005-12-09, last modified 2018-03-17

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