Denatured ethanol, release into gasoline residuals, Part 1: Source behaviour

Denatured ethanol, release into gasoline residuals, Part 1: Source behaviour

Author Freitas, Juliana G. Autor UNIFESP Google Scholar
Barker, James F. Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Univ Waterloo
Abstract With the increasing use of ethanol in fuels, it is important to evaluate its fate when released into the environment. While ethanol is less toxic than other organic compounds present in fuels, one of the concerns is the impact ethanol might have on the fate of gasoline hydrocarbons in groundwater. One possible concern is the spill of denatured ethanol (E95: ethanol containing 5% denaturants, usually hydrocarbons) in sites with pre-existing gasoline contamination. in that scenario, ethanol is expected to increase the mobility of the NAPL phase by acting as a cosolvent and decreasing interfacial tension. To evaluate the E95 behaviour and its impacts on pre-existing gasoline, a field test was performed at the CFB-Borden aquifer. Initially gasoline contamination was created releasing 200 L of E10 (gasoline with 10% ethanol) into the unsaturated zone. One year later, 184 L of E95 was released on top of the gasoline contamination. the site was monitored using soil cores, multilevel wells and one glass access tube. At the end of the test, the source zone was excavated and the compounds remaining were quantified. E95 ethanol accumulated and remained within the capillary fringe and unsaturated zone for more than 200 days, despite similar to 1 m oscillations in the water table. the gasoline mobility increased and it was redistributed in the source zone. Gasoline NAPL saturations in the soil increased two fold in the source zone. However, water table oscillations caused a separation between the NAPL and ethanol: NAPL was smeared and remained in deeper positions while ethanol moved upwards following the water table rise. Similarly, the E95 denaturants that initially were within the ethanol-rich phase became separated from ethanol after the water table oscillation, remaining below the ethanol rich zone. the separation between ethanol and hydrocarbons in the source after water table oscillation indicates that ethanol's impact on hydrocarbon residuals is likely limited to early times. (C) 2013 Elsevier B.V. All rights reserved.
Keywords Ethanol
Gasoline
Source zone
Capillary fringe
Field test
Language English
Date 2013-05-01
Published in Journal of Contaminant Hydrology. Amsterdam: Elsevier B.V., v. 148, p. 67-78, 2013.
ISSN 0169-7722 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 67-78
Origin http://dx.doi.org/10.1016/j.jconhyd.2012.12.010
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000318192800006
URI http://repositorio.unifesp.br/handle/11600/36227

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