Final Technical Report EMSP 70045 Investigation of Pore Scale Processes That Affect Soil Vapor Extraction
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.
- Research Organization:
- University of Illinois at Urbana-Champaign, Urbana, IL (US)
- Sponsoring Organization:
- USDOE Office of Environmental Management (EM); USDOE Office of Science (SC) (US)
- DOE Contract Number:
- FG07-99ER15007
- OSTI ID:
- 835019
- Report Number(s):
- DOE/ER/15007-Final Technical Report; EMSP70045; TRN: US0500155
- Resource Relation:
- Other Information: PBD: 10 Dec 2004
- Country of Publication:
- United States
- Language:
- English
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Investigation of Pore Scale Processes That Affect Soil Vapor Extraction
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Related Subjects
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