HR: 0830h
AN: H51A-06    [Abstracts]
TI: Immobilization of uranium (VI) in structured saprolite with microbial U(VI) reduction
AU: * Kim, Y
EM: kimy1@ornl.gov
AF: Oak Ridge National Laboratory, Environmental Sciences Division, P.O. Box 2008, Oak Ridge, TN 37831 United States
AU: Brooks, S C
EM: brookssc@ornl.gov
AF: Oak Ridge National Laboratory, Environmental Sciences Division, P.O. Box 2008, Oak Ridge, TN 37831 United States
AU: Kamolpornwijit, W
EM: Kamolpornwiw@ornl.gov
AF: Oak Ridge National Laboratory, Environmental Sciences Division, P.O. Box 2008, Oak Ridge, TN 37831 United States
AU: Scheibe, T D
EM: tim.scheibe@pnl.gov
AF: Pacific Northwest National Laboratory, P.O. Box 999, K9-36, Richland, WA 99352 United States
AU: Roden, E E
EM: eroden@bsc.as.ua.edu
AF: The University of Alabama, Department of Biological Sciences, Tuscaloosa, AL 35487 United States
AB: Lab-scale biostimulation experiments were conducted to investigate microbial reduction of uranium (VI) in intact saprolite columns. Three intact saprolite columns derived from fractured, interbedded shale, limestone, sandstone sequences were collected and transported to the laboratory. The columns were first flushed with a solution of 10μM U(VI) in 50mM NaCl. Once the effluent U/U₀ reached approximately 0.5, each column was treated differently. The injection of U(VI) was continued for Column 1 to serve as a control. U(VI), as well as ethanol and nutrients were supplied to Column 2 to stimulate indigenous metal reducing activity. In addition to electron donor and nutrients, the soluble electron shuttling compound anthraquinone-2, 6-disulfonate (AQDS) was supplied to Column 3. AQDS has the ability to diffuse into micropore regions that remain inaccessible to bacterial cells potentially increasing the region of influence of bacterial metal-reducing activity. Successful immobilization of U(VI) will be indicated by incomplete mass recovery in the column effluent relative to the control column (no ethanol addition). The experiment provides lab-scale evaluation of hypothesis that U (VI) in low-permeability porous regions (micropores) of saprolite can be immobilized and isolated from mobile groundwater by stimulating localized microbial U (VI) reduction in hydrologically accessible fractured zones (meso and macropores).
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: 2005 Joint Assembly