Modeling surfactant-enhanced nonaqueous-phase liquid remediation of porous media
- Pacific Northwest National Lab., Richland, WA (United States). Environmental Technology Div.
A mathematical model is developed to investigate the main processes associated with surfactant-enhanced nonaqueous-phase liquid (NAPL) remediation of porous media. The model couples four nonlinear mass balance conservation equations (i.e., water, NAPL-phase organic, aqueous-phase organic, and aqueous-phase surfactant) that incorporate aqueous- and NAPL-phase migration and transport of aqueous-phase dissolved surfactant and organics. Rate-limited solubilization of the organic into the aqueous phase is represented by a linear driving force expression and is dependent on the surfactant-enhanced equilibrium concentration. Surfactant-enhanced mobilization of the NAPL phase is incorporated using surfactant concentration-dependent interfacial tension lowering, scaled relative permeability-saturation-capillary pressure relations, and trapping number-dependent effective residual saturations for the nonwetting liquid. Sorption of surfactant is assumed to conform to a Langmuir isotherm model, whereas organic sorption is modeled using a linear isotherm with a surfactant and soil-organic content-dependent retardation coefficient. The model is used to simulate experiments described by Pennel et al. (1996) in which the NAPL perchloroethylene was flushed from sand columns using different surfactant solutions.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 305441
- Journal Information:
- Soil Science, Journal Name: Soil Science Journal Issue: 12 Vol. 163; ISSN 0038-075X; ISSN SOSCAK
- Country of Publication:
- United States
- Language:
- English
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