Date of Award

2016

Document Type

Campus Access Master's Thesis

Degree Name

Master of Science in Environmental Engineering (MS)

Administrative Home Department

Department of Civil and Environmental Engineering

Advisor 1

Eric Seagren

Advisor 2

Jennifer Becker

Committee Member 1

Susan Bagley

Abstract

Tetrachloroethene (PCE) is a common groundwater contaminant. Several bacterial strains have the ability to respire PCE and/or its daughter products through dehalorespiration, and can be used to completely detoxify aqueous PCE. PCE contamination is often present as a dense non-aqueous phase liquid (DNAPL), which serves as a long-term contaminant source that slowly dissolves into the groundwater. This study examined the potential for dehalorespiration to bioenhance dissolution in an intermediate-scale flow cell (ISFC) containing a PCE DNAPL pool. The overall project goal was to examine how the interactions between two dehalorespirers, Desulfuromonas michiganensis BB1 and Dehalococcoides mccartyi 195, impacted PCE dissolution and detoxification. Abiotic experiments indicated that PCE dissolution was affected by porous medium heterogeneities that altered the hydrodynamic conditions. Introduction of the two dehalorespirers initially bioenhanced the PCE dissolution rate by 2-3X, with Dsm. michiganensis BB1 dominating. Microbial growth later caused bioclogging, which increased flow adjacent to the DNAPL-aqueous interface, and further enhanced PCE dissolution.

Available for download on Tuesday, August 01, 2017

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