Modeling Transport of Chemotactic Bacteria in Granular Media with Distributed Contaminant Sources

Abstract

Chemotaxis has the potential to improve bioremediation strategies by enhancing the transport of pollutant-degrading bacteria to the source of contamination, leading to increased pollutant accessibility and biodegradation. This computational study extends work reported previously in the literature to include predictions of chemotactic bacterial migration in response to multiple localized contaminant sources within porous media. An advection-dispersion model, in which chemotaxis was represented explicitly as an additional advection-like term, was employed to simulate the transport of bacteria within a sand-packed column containing a distribution of chemoattractant sources. Simulation results provided insight into attractant and bacterial distributions within the column. In particular, it was found that chemotactic bacteria exhibited a distinct biased migration toward contaminant sources that resulted in a 30% decrease in cell recovery, and concomitantly an enhanced retention within the sand column, compared to the nonchemotactic control. Model results were consistent with experimental observations. Parametric studies were conducted to provide insight into the influence of chemotaxis parameters on bacterial migration and cell percent recovery. The model results provide a better understanding of the effect of chemotaxis on bacterial transport in response to distributed contaminant sources.

Tuning chemotactic and diffusiophoretic spreading via hydrodynamic flows

“…The ability to predict the chemotactic/diffusiophoretic colloid motion and distribution is central to biological processes such as biofilm formation 3,7 and applications including drug delivery, enhanced oil recovery, and bioremediation of aquifers. 2,27,28 A challenge in such predictions is the presence of background hydrodynamic flows, which affects the transport of the solute and the colloids. Hydrodynamic flows occur naturally as in biofluid flows in drug delivery, or can be imposed as in chemical flooding in oil recovery.…”

Macrotransport theory for diffusiophoretic colloids and chemotactic microorganisms

“…Runs are extended in favourable directions, resulting in a net movement of the bacteria up/down the gradient of the solute (attractant/repellent) (Brown & Berg 1974;Wu et al 2006). Chemotaxis is central to phenomena such as biofilm formation (Eisenbach et al 2004) and has been utilized in bioremediation including aquifer restoration (Ford & Harvey 2007;Adadevoh et al 2017). In chemotactic log-sensing, M is the chemotactic sensitivity.…”

“…2004) and has been utilized in bioremediation including aquifer restoration (Ford & Harvey 2007; Adadevoh et al. 2017). In chemotactic log-sensing, is the chemotactic sensitivity.…”

Controlling pore-scale processes to tame subsurface biomineralization

“…The appropriate averaging of these small-scale processes would allow upscaling by eliminating the need to model them explicitly. Advection–dispersion model is commonly used in continuum models to simulate the transport of bacteria through porous media, and more recently, chemotaxis has been incorporated as an additional advection-like term (Adadevoh et al 2017 ). However, this approach fails to predict the bacterial residence time and distribution in the host matrix, and therefore the rate of biologically-driven reactions.…”