Evaluation of Thermal Effects on the Dissolution of a Nonaqueous Phase Liquid in Porous Media

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• 作者：Paul T. Imhoff ; Angela Frizzell ; and Cass T. Miller
• 刊名：Environmental Science & Technology
• 出版年：1997
• 出版时间：June 1997
• 年：1997
• 卷：31
• 期：6
• 页码：1615 - 1622
• 全文大小：164K
• 年卷期：v.31,no.6(June 1997)
• ISSN：1520-5851

文摘

Porous media contaminated with nonaqueous phase liquids(NAPLs) may serve as a long-term source of groundwatercontamination. To remove NAPLs and thereby mitigatethe potential impact to the environment and human health,it has been suggested that contaminated media be flushedwith cosolvents, surfactants, hot water, or steam. Inthisstudy, hot water flooding was used to remediate a porousmedium contaminated with tetrachlorethylene (PCE) atresidualsaturation in an otherwise water-saturated medium.Theeffect of temperature on the physical and chemicalproperties of the system was well characterized, and aquantitative assessment was made of the effect oftemperatureon PCE dissolution. A comparison of the results fromthedissolution experiments with existing dimensionlesscorrelations for NAPL dissolution in porous mediaelucidatedthe role of the aqueous-phase viscosity and the NAPLspecies aqueous-phase diffusivity.Nonaqueous-aqueousphase mass transfer rate coefficients measured for thissystem were put in dimensionless form (Sherwood number)and fitted to a power-law model. The Sherwood numberwas found to vary with the Schmidt number toapproximately the 0.5 power, as suggested by previousinvestigators. This result is expected to apply tononaqueous-aqueous phase mass transfer in other systems whereaqueous-phase properties are altered by the addition ofchemicals.