Electrokinetic-enhanced removal of toluene from physically heterogeneous granular porous media

Gill, Richard Thomas, Thornton, Steven, Harbottle, Michael J. ORCID: https://orcid.org/0000-0002-6443-5340 and Smith, Jonathan W. N. 2021. Electrokinetic-enhanced removal of toluene from physically heterogeneous granular porous media. Quarterly Journal of Engineering Geology and Hydrogeology 54 (3) , qjegh2020-073. 10.1144/qjegh2020-073

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Abstract

Electrokinetics (EK) was applied to enhance biodegradation of toluene in a low hydraulic conductivity (K) zone of a physically heterogeneous water-saturated granular porous media. The hypothesis tested was that EK transport processes, which operate independently of advection, can deliver a limiting amendment, nitrate, across a high- /lowK boundary to stimulate bioremediation. Two types of experiment were evaluated: (1) bench-scale tests that represented the active EK system and physically heterogeneous sediment configuration; and (2) microcosms that represented biodegradation in the bench-scale tests under ideal conditions. The bench-scale experiment results showed a rapid decrease in toluene concentration during the application of EK that was attributed to electroosmotic removal from low-K zones. Comparison of toluene removal rates by electroosmosis and biodegradation (microcosm) confirmed that electroosmosis was the most effective mechanism under the conditions evaluated. Overall, this work challenged the original hypothesis and indicates that, at the field scale, the most favourable conditions for biodegradation are likely to be achieved by applying EK to increase contaminant flux across the low-/high- K boundary (out of the low-K zone) and allowing biodegradation to occur in the high-K zone either by natural attenuation or enhanced by amendment addition.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Engineering
Additional Information:	This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License (http://creativecommons.org/licenses/by/4.0/). Published by The Geological Society of London. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics
Publisher:	Geological Society
ISSN:	1470-9236
Funders:	EPSRC, Shell
Date of First Compliant Deposit:	3 November 2020
Date of Acceptance:	10 October 2020
Last Modified:	06 May 2023 01:03
URI:	https://orca.cardiff.ac.uk/id/eprint/136113

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