INFILTRATION AND REDISTRIBUTION OF ORGANIC LIQUIDS IN LAYERED POROUS-MEDIA

The remediation of many toxic waste sites throughout the world requires a better understanding of the flow of organic liquids in the vadose zone. The infiltration and redistribution of three water-immiscible oils into columns filled with porous material containing different textural layers are reported. In some experiments, oil followed water into the columns and in others, water followed oil. An explicit, one-dimensional, multiphase flow code was used to model the results. The numerical model contains elements of code that: (i) mimic the Haines jump phenomenon in dry sand, (ii) account for oil entrapment when water infiltrates, (iii) include forces on the oil phase caused by surface-spreading pressures at the oil front in water-wetted pores, (iv) include forces on the oil phase caused by water intrusion into hydrophilic oil-saturated pores, and (v) generate a factor that matches the water potentials of textural layers for the initial boundary conditions. In general, the model did a reasonable job of predicting the distribution of both water and oil 8 h after infiltration was started, though some unresolved problems persist. The liquid potential matching factor and the hydrophobicity of the mineral particles induced by a transmission oil have practical applications. The matching factor may be easily adapted to all codes that model flow through layers. The in situ creation of hydrophobic mineral particles may prove useful for containing immiscible organic liquids that leak into the vadose zone.