The effect of surface-active solutes on water flow and contaminant transport in variably saturated porous media with capillary fringe effects

摘要

Organic contaminants that decrease the surface tension of water(surfactants)can have an effect on unsaturated flow through porous media due to dependence of capillary pressure on surface tension. We used an intermediate-scale 2D flow cell(2.44?1.53×0.108 m)packed with a fine silica sand to investigate surfactant-induced flow perturbations. Surfactant solution(7/100 1-butanol and dye tracer)was applied at a constant rate at a point source located on the soil surface above an unconfined synthetic aquifer with ambient groundwater flow and a capillary fringe of～55 cm.