Ethanol addition for enhancing denitrification at the uranium mill tailing site in Monument Valley, AZ

Andrew K. Borden, Mark L Brusseau, K. C. Carroll, Andrew McMillan, Nihat H. Akyol, Justin Berkompas, Ziheng Miao, Fiona Jordan, Geoff Tick, W. Jody Waugh, Ed P. Glenn

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Past mining and processing of uranium ore at a former uranium mining site near Monument Valley, AZ has resulted in nitrate contamination of groundwater. The objective of this study was to investigate the potential of ethanol addition for enhancing the reduction of nitrate in groundwater. The results of two pilot-scale field tests showed that the concentration of nitrate decreased, while the concentration of nitrous oxide (a product of denitrification) increased. In addition, changes in aqueous concentrations of sulfate, iron, and manganese indicated that the ethanol amendment caused a change in prevailing redox conditions. The results of compound-specific stable isotope analysis for nitrate-nitrogen indicated that the nitrate concentration reductions were biologically mediated. Denitrification rate coefficients estimated for the pilot tests were approximately 50 times larger than resident-condition (non-enhanced) values obtained from prior characterization studies conducted at the site. The nitrate concentrations in the injection zone have remained at levels three orders of magnitude below the initial values for many months, indicating that the ethanol amendments had a long-term impact on the local subsurface environment.

Original languageEnglish (US)
Pages (from-to)755-763
Number of pages9
JournalWater, Air, and Soil Pollution
Volume223
Issue number2
DOIs
Publication statusPublished - Feb 2012

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Keywords

  • Denitrification
  • Enhanced bioremediation
  • Groundwater quality
  • Natural attenuation
  • Stable isotopes

ASJC Scopus subject areas

  • Pollution
  • Environmental Chemistry
  • Environmental Engineering
  • Ecological Modeling
  • Water Science and Technology

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