INFILTRATION AND REDISTRIBUTION OF ORGANIC LIQUIDS IN LAYERED POROUS-MEDIA

The remediation of many toxic waste sites throughout the world require s a better understanding of the flow of organic liquids in the vadose zone. The infiltration and redistribution of three water-immiscible oi ls into columns filled with porous material containing different textu ral layers are reported. In some experiments, oil followed water into the columns and in others, water followed oil. An explicit, one-dimens ional, multiphase flow code was used to model the results. The numeric al model contains elements of code that: (i) mimic the Haines jump phe nomenon in dry sand, (ii) account for oil entrapment when water infilt rates, (iii) include forces on the oil phase caused by surface-spreadi ng pressures at the oil front in water-wetted pores, (iv) include forc es on the oil phase caused by water intrusion into hydrophilic oil-sat urated pores, and (v) generate a factor that matches the water potenti als of textural layers for the initial boundary conditions. In general , the model did a reasonable job of predicting the distribution of bot h water and oil 8 h after infiltration was started, though some unreso lved problems persist. The liquid potential matching factor and the hy drophobicity of the mineral particles induced by a transmission oil ha ve practical applications. The matching factor may be easily adapted t o all codes that model flow through layers. The in situ creation of hy drophobic mineral particles may prove useful for containing immiscible organic liquids that leak into the vadose zone.