Geochemical engineering design tools for uranium in situ recovery : the HYDROGEOCHEM codes.
- National Central University, Jhongli City, Taiwan
- University of Central Florida, Orlando, FL
Geochemical Engineering Design (GED) is based on applications of the principles and various computer models that describe the biogeochemistry and physics of removal of contaminants from water by adsorption, precipitation and filtration. It can be used to optimize or evaluate the efficiency of all phases of in situ recovery (ISR). The primary tools of GED are reactive transport models; this talk describes the potential application of the HYDROGEOCHEM family of codes to ISR. The codes can describe a complete suite of equilibrium or kinetic aqueous complexation, adsorption-desorption, precipitation-dissolution, redox, and acid-base reactions in variably saturated media with density-dependent fluid flow. Applications to ISR are illustrated with simulations of (1) the effectiveness of a reactive barrier to prevent off-site uranium migration and (2) evaluation of the effect of sorption hysteresis on natural attenuation. In the first example, it can be seen that the apparent effectiveness of the barrier depends on monitoring location and that it changes over time. This is due to changes in pH, saturation of sorption sites, as well as the geometry of the flow field. The second simulation shows how sorption hysteresis leads to observable attenuation of a uranium contamination plume. Different sorption mechanisms including fast (or reversible), slow, and irreversible sorption were simulated. The migration of the dissolved and total uranium plumes for the different cases are compared and the simulations show that when 50-100% of the sites have slow desorption rates, the center of mass of the dissolved uranium plume begins to move upstream. This would correspond to the case in which the plume boundaries begin to shrink as required for demonstration of natural attenuation.
- Research Organization:
- Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 1030308
- Report Number(s):
- SAND2010-7695C; TRN: US201124%%102
- Resource Relation:
- Conference: Proposed for presentation at the Geological Society of America 2010 Annual Conference held October 31-November 3, 2010 in Denver, CO.
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ADSORPTION
ATTENUATION
BIOGEOCHEMISTRY
COMPUTERS
CONTAMINATION
DESORPTION
FILTRATION
FLUID FLOW
GEOMETRY
HYSTERESIS
KINETICS
MONITORING
NATURAL ATTENUATION
PHYSICS
PLUMES
PRECIPITATION
REMOVAL
SATURATION
SORPTION
URANIUM