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Title: Final Technical Report EMSP 70045 Investigation of Pore Scale Processes That Affect Soil Vapor Extraction

Abstract

Dense nonaqueous phase liquid (DNAPL) contamination in the vadose zone is a significant problem at Department of Energy sites. Soil vapor extraction (SVE) is commonly used to remediate DNAPLs from the vadose zone. In most cases, a period of high recovery has been followed by a sustained period of low recovery. This behavior has been attributed to multiple processes including slow interphase mass transfer, retarded vapor phase transport, and diffusion from unswept zones of low permeability. This research project used a combination of laboratory experimentation and mathematical modeling to determine how these various processes interact to limit the removal of DNAPL components in heterogeneous porous media during SVE. Our results were applied to scenarios typical of the carbon tetrachloride spill zone at the Hanford Site. Our results indicate that: (a) the initial distribution of the spilled DNAPL (i.e., the spill-zone architecture) has a major influence upon the performance of any subsequent SVE operations; (b) while the pattern of higher and lower conductivity soil zones has an important impact upon spill zone architecture, soil moisture distribution plays an even larger role when there are large quantities of co-disposed waste-water (as in the Hanford scenario); (c) depending upon soil moisture dynamics, liquidmore » DNAPL that is trapped by surrounding water is extremely difficult to remove by SVE; (d) natural barometric pumping can remove a large amount of the initial DNAPL mass for spills occurring close to the land surface, and hence the initial spilled inventory will be over-estimated if this process is neglected.« less

Authors:
; ;
Publication Date:
Research Org.:
University of Illinois at Urbana-Champaign, Urbana, IL (US)
Sponsoring Org.:
USDOE Office of Environmental Management (EM); USDOE Office of Science (SC) (US)
OSTI Identifier:
835019
Report Number(s):
DOE/ER/15007-Final Technical Report
EMSP70045; TRN: US0500155
DOE Contract Number:  
FG07-99ER15007
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 10 Dec 2004
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 42 ENGINEERING; 54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; ARCHITECTURE; CARBON TETRACHLORIDE; CONTAMINATION; DIFFUSION; MASS TRANSFER; MOISTURE; PERFORMANCE; PERMEABILITY; PUMPING; REMOVAL; SOILS; WASTE WATER; WATER; SOIL VAPOR EXTRACTION; MULTIPHASE FLOW; MAGNETIC RESONANCE IMAGING

Citation Formats

Valocchi, Albert J., Werth, Charles W., and Webb, Andrew W. Final Technical Report EMSP 70045 Investigation of Pore Scale Processes That Affect Soil Vapor Extraction. United States: N. p., 2004. Web. doi:10.2172/835019.
Valocchi, Albert J., Werth, Charles W., & Webb, Andrew W. Final Technical Report EMSP 70045 Investigation of Pore Scale Processes That Affect Soil Vapor Extraction. United States. doi:10.2172/835019.
Valocchi, Albert J., Werth, Charles W., and Webb, Andrew W. Fri . "Final Technical Report EMSP 70045 Investigation of Pore Scale Processes That Affect Soil Vapor Extraction". United States. doi:10.2172/835019. https://www.osti.gov/servlets/purl/835019.
@article{osti_835019,
title = {Final Technical Report EMSP 70045 Investigation of Pore Scale Processes That Affect Soil Vapor Extraction},
author = {Valocchi, Albert J. and Werth, Charles W. and Webb, Andrew W.},
abstractNote = {Dense nonaqueous phase liquid (DNAPL) contamination in the vadose zone is a significant problem at Department of Energy sites. Soil vapor extraction (SVE) is commonly used to remediate DNAPLs from the vadose zone. In most cases, a period of high recovery has been followed by a sustained period of low recovery. This behavior has been attributed to multiple processes including slow interphase mass transfer, retarded vapor phase transport, and diffusion from unswept zones of low permeability. This research project used a combination of laboratory experimentation and mathematical modeling to determine how these various processes interact to limit the removal of DNAPL components in heterogeneous porous media during SVE. Our results were applied to scenarios typical of the carbon tetrachloride spill zone at the Hanford Site. Our results indicate that: (a) the initial distribution of the spilled DNAPL (i.e., the spill-zone architecture) has a major influence upon the performance of any subsequent SVE operations; (b) while the pattern of higher and lower conductivity soil zones has an important impact upon spill zone architecture, soil moisture distribution plays an even larger role when there are large quantities of co-disposed waste-water (as in the Hanford scenario); (c) depending upon soil moisture dynamics, liquid DNAPL that is trapped by surrounding water is extremely difficult to remove by SVE; (d) natural barometric pumping can remove a large amount of the initial DNAPL mass for spills occurring close to the land surface, and hence the initial spilled inventory will be over-estimated if this process is neglected.},
doi = {10.2172/835019},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2004},
month = {12}
}