Craig S. Criddle

Field-Scale Evaluation of Biological Uranium Reduction and Reoxidation in the Near-Source Zone at the NABIR Field Research Center in Oak Ridge, TN

The primary objective of the project is to advance the understanding and predictive capability of coupled hydrological, geochemical, and microbiological processes that control the in situ transport and bioremediation radionuclides and co-contaminants at multiple scales. Specific objectives include: (1) Investigate the feasibility of in situ bioremediation of uranium in a highly contaminated region within the subsurface of Area 3 of the DoE ERSP FRC (2) Using a variety of tracer strategies, develop and model a system that establishes hydraulic control of the target region for biostimulation (3) Perform long term in situ biostimulation studies that create a microbial communities capable of reducing residual nitrate to N2 and mobile U(VI) to sparingly soluble U(IV) (4) Use a variety of solid and solution phase interrogation techniques to quantify the extent of in situ reduction and immobilization of U(VI). (5) Investigate a variety of geochemical factors that influence the stability and possible reoxidation of reduced uranium.