Recovery of Coal Tar and Creosote from Porous Media: The Influence of Wettability |
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| Authors: | Daniel A. Hugaboom Susan E. Powers |
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| Affiliation: | Daniel A. Hugaboom;has an M.S. in civil engineering from Clarkion University, Potsdam, New York. He currently works for Carolio Engineers in Boise, Idaho ). Susan E. Powers;, Ph.D., P.E., is a professor in the Department of Civil and Environmental Engineering at Clarkson University(). Her research investigates the fate, transport, and remediation of several types of complex NAPL mixtures in the sub-surface. |
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| Abstract: | The recovery of coal tar or creosote, which are dense nonaqueous phase liquids (DNAPLs), from the subsurface has been used as a means of site remediation at several former manufactured-gas plant sites and wood-treating facilities. Surface-active components in these complex DNAPL can have acid/base and surfactant characteristics that can significantly affect the wettability in these systems, with a reversal to DNAPL wetting at low pHs. These changes in wettability as a function of pH were employed to evaluate their significance on waterflooding efficiency in one-dimensional soil columns. The use of pH as a means of controlling wettability resulted in identical density and viscosity properties between the water-and DNAPL-wet conditions. At some of the higher pHs, the interracial tension changed as well as the wettability. Maintaining a constant dimensionless capillary number was used to minimize the effect of this variable. DNAPL saturations remaining in the DNAPL-wet systems after waterflooding ranged from 38% to 47%. Significantly lower final DNAPL saturations were achieved for water-wetting systems (15% to 30%). |
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