IngentaConnect Mathematical Modeling of Chemotactic Bacterial Transport through ...

Authors: Olson, Mira¹; Ford, Roseanne²; Smith, James³; Fernandez, Erik²

Source: Bioremediation Journal, Volume 10, Numbers 1-2, -2/January-June 2006 , pp. 13-23(11)

Abstract:

The impact of bacterial chemotaxis on in situ ground-water bioremediation remains an unanswered question. Although bacteria respond to chemical gradients in aqueous environments and under no-flow conditions, it is unclear whether they can also respond in porous media with advective flow to improve overall contaminant degradation. The effect of chemotaxis is most profound in regions with sharp chemical gradients, most notably around residual nonaqueous phase liquid (NAPL) ganglia and surrounding clay lenses or aquitards with trapped contamination. The purpose of this study is to simulate bacterial transport through a two-dimensional subsurface environment, containing one region of low permeability with trapped contaminant surrounded above and below by two regions of higher permeability. Using mathematical predictions of the effect of pore size on measured bacterial transport parameters, the authors observe a 50% decrease in both motility and chemotaxis in the finer-grained, low-permeability porous medium. The authors simulate how chemotaxis affects bacterial migration to the contaminated region under various flow and initial conditions. Results indicate that bacteria traveling through a high-permeability region with advective flow can successfully migrate toward and accumulate around a contaminant diffusing from a lower permeability region.

Keywords: bacterial transport; chemotaxis; transport modeling; trichloroethylene

Document Type: Research article

DOI: 10.1080/10889860600842886

Affiliations: 1: Department of Civil, Architectural and Environmental Engineering, Drexel University, Philadelphia, Pennsylvania, USA 2: Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia, USA 3: Department of Civil Engineering, University of Virginia, Charlottesville, Virginia, USA

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Mathematical Modeling of Chemotactic Bacterial Transport through a Two-Dimensional Heterogeneous Porous Medium