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Using Either Hydrogen or Dithionite as Reductant in Uranium Contaminated Groundwater at Post-Leach Uranium Mining Sites, South Texas

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2012 ASEE Annual Conference & Exposition


San Antonio, Texas

Publication Date

June 10, 2012

Start Date

June 10, 2012

End Date

June 13, 2012



Conference Session

NSF Grantees' Poster Session

Tagged Topic

NSF Grantees Poster Session

Page Count


Page Numbers

25.13.1 - 25.13.14



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Paper Authors


Lee Clapp P.E. Texas A&M University, Kingsville

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Lee Clapp is Associate Professor in environmental engineering.

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Mohamed Abdelrahman Texas A&M University, Kingsville

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Mohamed Abdelrahman received the B.S. and M.S. degrees in electrical engineering and engineering physics from Cairo University, Egypt in 1988 and 1992, respectively. He received an M.S. and a Ph.D. in measurement and control and nuclear engineering from Idaho State University in 1994 and 1996, respectively. He is currently the Associate Dean of Engineering at Texas A&M University, Kingsville. Abdelrahman's research focus is industrial applications of sensing and control with major research funding from the U.S. Department of Energy, National Science Foundation, and industry. He has also focused on collaborative and innovative educational research. Abdelrahman is passionate about outreach activities for popularizing engineering research and education. His activities in that arena included NSF funded sites for research experience for undergraduates and research experience for Teachers. He has published his research results in more than 90 papers in refereed journals and conference proceedings and 30+ technical reports.

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Petronilo Estandarte Pana LBJ Middle School, PSJA ISD

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B.S.E.M., M.S. GeoEng'g

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Using either Hydrogen or Dithionite as Reductant in Uranium Contaminated Groundwater at Post-Leach Uranium Mining Sites, South TexasAbstract This paper reports on uranium being a major groundwater contaminant in ISL miningsites located in South Texas. This research is about modeling, simulations and studies usingPHREEQC, a computer program from USGS, on how the two (2) reductants hydrogen gas (H2)and dithionite (Na2S2O4) will induce the reduction of U(VI) to U(IV) and the associated speciesin the uranium contaminated groundwater. However, before any development of new technologyand/or techniques in uranium groundwater restoration, an integrated understanding of the sitehydrogeology, geochemistry, and environmental hazards in ISL mining operations are of utmostimportance. ISL produces 90% of uranium mined in the US. In order to assess the extent of uranium remobilization at the end of the life cycle of anin-situ sediment reduction process a series of laboratory scale experiments and computersimulations was conducted using chemical reductants such as hydrogen gas and dithionitesolution. The uranium species that occur naturally in the +6 valence state [U (VI)] willaccumulate through the reduction and under precipitation conditions in the +4 valence state as U(IV). The important question is of how far the presence of uranium deposits is explored andmined by ISL mining method with utmost considerations from the surface environmentalstandpoint and most important groundwater. The deposition of uranium depends on the localredox state of groundwater flow, so if the groundwater is in reducing conditions, there is littleincentive for uranium and allied elements to be mobilized. However, if conditions are oxidizing,a large uranium deposition can extend far down dip. Likewise, uranium decay products (He, Rn,Ra, Pb, Th), have also variable mobility. Basically, the restoration of groundwater is generally the highest single cost and averagesabout 40% of the total costs of decommissioning of uranium mine sites. The results of thesephreeqc simulations and studies will be compared to that of laboratory scale experimentation. A learning module based on the legacy cycle concept is developed that challenges thestudents to think through the processes and steps required to determine the level ofcontamination and the amount of restoration required to return groundwater to safe levels. Thislearning module will be introduced into high school mathematics and science classes during the2011-2012 school year. Assessment of the students’ performance will be carried out andreported.

Clapp, L., & Abdelrahman, M., & Pana, P. E. (2012, June), Using Either Hydrogen or Dithionite as Reductant in Uranium Contaminated Groundwater at Post-Leach Uranium Mining Sites, South Texas Paper presented at 2012 ASEE Annual Conference & Exposition, San Antonio, Texas. 10.18260/1-2--20769

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