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J Contam Hydrol

Title:		Anaerobic biodegradation of dissolved ethanol in a pilot-scale sand aquifer: Gas phase dynamics
Author(s):		McLeod HC; Roy JW; Smith JE;
Address:		"School of Geography and Earth Sciences, McMaster University, Hamilton, Ontario, Canada. School of Geography and Earth Sciences, McMaster University, Hamilton, Ontario, Canada; Water Science and Technology Directorate, Environment and Climate Change Canada, Burlington, Ontario, Canada. Electronic address: jim.roy@canada.ca"
Journal Title:		J Contam Hydrol
Year:		2018
Volume:		20180717
Issue:
Page Number:		62 - 72
DOI:		10.1016/j.jconhyd.2018.07.003
ISSN/ISBN:		1873-6009 (Electronic) 0169-7722 (Linking)
Abstract:		"Groundwater contamination from ethanol (e.g., alternative fuels) can support vigorous biodegradation, with many possible reactions producing dissolved gases. The objective of this study was to improve the understanding of the development and evolution of trapped gas phase changes occurring within an ethanol plume undergoing biodegradation. The experiment performed involved highly detailed spatial and temporal monitoring of gas phase saturations using Time Domain Reflectometry probes embedded in a 2-dimensional (175?ª+cm high?ª+x?ª+525?ª+cm long) synthetic aquifer (homogeneous sand tank with horizontal groundwater flow). Ethanol injection immediately promoted gas-producing reactions, including: fermentation, denitrification, sulphate-reduction and iron(III)-reduction, with methanogenesis developing between 69 and 109?ª+days. Substantial in situ increases in trapped gas were observed over ~330?ª+days, with maximum gas saturations reaching 27% of the pore volume. Despite sustained gas production, this maximum was never exceeded, likely due to the onset of gas phase mobilization (i.e., ebullition) upon reaching a buoyancy-capillarity threshold. Reductions in the quasi-saturated hydraulic conductivity, resulting from the gas phase accumulation, were restricted by ebullition to a factor of
Keywords:		"Biodegradation, Environmental *Ethanol/metabolism Ferric Compounds Gases/analysis *Groundwater Iron/metabolism Oxidation-Reduction Silicon Dioxide Water Pollutants, Chemical/analysis Biodegradation Ebullition Ethanol Gasohol Groundwater Trapped gas;"
Notes:		"MedlineMcLeod, Heather C Roy, James W Smith, James E eng Research Support, Non-U.S. Gov't Netherlands 2018/07/29 J Contam Hydrol. 2018 Aug; 215:62-72. doi: 10.1016/j.jconhyd.2018.07.003. Epub 2018 Jul 17"