HR: 1340h
AN: H53F-1499    [Abstracts]
TI: Experimental and Numerical Investigation of Subsurface Desiccation
AU: * Wietsma, T
AF: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, United States
AU: Oostrom, M
EM: mart.oostrom@pnl.gov
AF: Hydrology Group, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, United States
AU: Covert, M
AF: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, United States
AB: Traditional remediation techniques are not applicable at some locations at the Hanford site where contaminants in the unsaturated zone are located too deep and spread over a large area. Non-reactive or mobile contaminants might reach the water table at unacceptable concentrations. Desiccation, in addition to surface infiltration control, is considered to have considerable benefits for deep vadose zone application and is currently viewed as a potentially viable deep vadose zone technology for Hanford. Several technical issues need to be addressed as part of developing and applying soil desiccation as a viable technique for deep vadose zone treatment. Wedge-shaped, two dimensional experiments have been conducted in an attempt to provide insight into key issues regarding 1) energy limitations on the volume of water that can be removed, 2) osmotic effects during soil drying, and, 3) potential remobilization of contaminants after cessation of desiccation. The flow cell experiments have been conducted in homogeneous and heterogeneous systems for various imposed boundary conditions. A dual-energy gamma system was used to determine water saturations for some experiments, while temperature and humidity have been measured with internal probes. Experimental variables are temperature and rate of the injected air, boundary conditions (zero flux and constant temperature), and porous media properties. The experimental results are compared with simulations conducted with the STOMP simulator.
DE: 1818 Evapotranspiration
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: 2007 Fall Meeting