Remediation of NAPL below the water table by steam-induced heat conduction

• Published in: Journal of contaminant hydrology Vol. 72; no. 1; pp. 207 - 225
• Main Authors: Gudbjerg, J, Sonnenborg, T.O, Jensen, K.H
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.2004; Elsevier Science
• Subjects: Boiling; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Monitoring - instrumentation; Environmental Monitoring - methods; Exact sciences and technology; Hot Temperature; Hydrogeology; Hydrology. Hydrogeology; Modeling; Models, Theoretical; Pollution, environment geology; Porosity; Remediation; Sand box models; Soil Pollutants - analysis; Steam; Steam injection; Time Factors; Transition Temperature; Trichloroethylene - chemistry; Water - chemistry; Water Movements; Water Pollutants - analysis; Steam injection; Remediation; Modeling; Boiling; Sand box models; experimental studies; interfaces; nonaqueous phase liquids; fine-grained materials; ground water; water table; hydrodynamics; pollution; tetrachloroethylene; remediation; sand; coarse-grained materials; numerical models; injection; porous media
• ISSN: 0169-7722; 1873-6009
• DOI: 10.1016/j.jconhyd.2003.11.001

Previous experimental studies have shown that NAPL will be removed when it is contacted by steam. However, in full-scale operations, steam may not contact the NAPL directly and this is the situation addressed in this study. A two-dimensional intermediate scale sand box experiment was performed where an organic contaminant was emplaced below the water table at the interface between a coarse and a fine sand layer. Steam was injected above the water table and after an initial heating period the contaminant was recovered at the outlet. The experiment was successfully modeled using the numerical code T2VOC and the dominant removal mechanism was identified to be heat conduction induced boiling of the separate phase contaminant. Subsequent numerical modeling showed that this mechanism was insensitive to the porous medium properties and that it could be evaluated by considering only one-dimensional heat conduction.