Transport and degradation of ethanol in groundwater

Yi Zhang, Imtiyaz A. Khan, Xun Hong Chen, Roy F. Spalding

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Ethanol is rapidly replacing methyl tert-butyl ether (MtBE), the primary fuel oxygenate in the US, and ethanol releases from spills and leaky underground storage tanks (LUSTs) are anticipated. Ethanol has received little attention as a potential groundwater contaminant. This study investigates the fate and transport of ethanol under transient conditions in a sand and gravel aquifer. A pulse containing approximately 220 mg L- 1 ethanol and 16 mg L - 1 bromide was injected into the shallow sand and gravel aquifer and monitored to estimate its persistence and transport. The plume was monitored for 2.5 months using downgradient multilevel samplers (MLSs). Values for ethanol retardation were measured from ethanol and bromide breakthrough data and compared to estimates using published Koc values for low carbon aquifer sediments (foc = 10 μg C g- 1 sediment). Ethanol transport was not retarded (R = 0.99). A 3-dimensional model reasonably simulated bromide and ethanol breakthrough curves. An average first-order decay constant was estimated to be 0.32 d- 1 (t1 / 2 = 2.2 d). At the second fence, 75% of the injected bromide and less than 3% of ethanol remained in the plume. Monitored terminal electron acceptor concentrations demonstrated that the majority of the ethanol was transformed by anaerobic processes other than denitrification and sulfate reduction.

Original languageEnglish (US)
Pages (from-to)183-194
Number of pages12
JournalJournal of Contaminant Hydrology
Volume82
Issue number3-4
DOIs
StatePublished - Jan 10 2006

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Keywords

  • Dispersion
  • Ethanol degradation rate
  • Half life
  • Nitrate reduction
  • Solute transport

ASJC Scopus subject areas

  • Environmental Chemistry
  • Water Science and Technology

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