Groundwater contamination from an inactive uranium mill tailings pile. 2. Application of a dynamic mixing model
At Riverton, Wyoming, low pH process waters from an abandoned uranium mill tailings pile have been infiltrating into and contaminating the shallow water table aquifer. The contamination process has been governed by transient infiltration rates, saturated-unsaturated flow, as well as transient chemical reactions between the many chemical species present in the mixing waters and the sediments. In the first part of this two-part series the authors presented field data as well as an interpretation based on a static mixing models. As an upper bound, the authors estimated that 1.7% of the tailings water had mixed with the native groundwater. In the present work they present the results of numerical investigation of the dynamic mixing process. The model, DYNAMIX (DYNamic MIXing), couples a chemical speciation algorithm, PHREEQE, with a modified form of the transport algorithm, TRUMP, specifically designed to handle the simultaneous migration of several chemical constituents. The overall problem of simulating the evolution and migration of the contaminant plume was divided into three sub problems that were solved in sequential stages. These were the infiltration problem, the reactive mixing problem, and the plume-migration problem. The results of the application agree reasonably with the detailed field data. The methodology developed in the present study demonstrates the feasibility of analyzing the evolution of natural hydrogeochemical systems through a coupled analysis of transient fluid flow as well as chemical reactions. It seems worthwhile to devote further effort toward improving the physicochemical capabilities of the model as well as to enhance its computational efficiency.
- Research Organization:
- Lawrence Berkeley Lab., CA
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 7094564
- Journal Information:
- Water Resour. Res.; (United States), Vol. 22:13
- Country of Publication:
- United States
- Language:
- English
Similar Records
Hydrology and geochemistry of the uranium mill tailings pile at Riverton, Wyoming. Part II. History matching. [Mathematical simulation of the observed fluid potentials within the tailings, and the observed distribution of various chemical species within and around the mill tailings]
Long-Term Stewardship at a Former Uranium Mill Tailings Site in Riverton, Wyoming - 17090
Related Subjects
ENVIRONMENTAL TRANSPORT
MATHEMATICAL MODELS
GROUND WATER
CONTAMINATION
RADIONUCLIDE MIGRATION
URANIUM
ALGORITHMS
FLUID FLOW
HYDROLOGY
MILL TAILINGS
MIXING
PH VALUE
PLUMES
WYOMING
ACTINIDES
ELEMENTS
FEDERAL REGION VIII
HYDROGEN COMPOUNDS
MASS TRANSFER
MATHEMATICAL LOGIC
METALS
NORTH AMERICA
OXYGEN COMPOUNDS
SOLID WASTES
TAILINGS
USA
WASTES
WATER
520300* - Environment
Aquatic- Radioactive Materials Monitoring & Transport- (1989)