A numerical transport model for oxygen‐ and nitrate‐based respiration linked to substrate and nutrient availability in porous media

Abstract

A model to simulate organic carbon biodegradation by facultative bacteria in saturated porous media using oxygen‐ and/or nitrate‐based respiration is developed. Basic assumptions incorporated into the model concept include a simulated particle‐bound microbial population comprised of heterotrophic, facultative bacteria in which metabolism is controlled by lack of either an organic carbon‐electron donor source (substrate), electron acceptor (O2 and/or NO3−), or mineral nutrient (NH4+), or all three simultaneously. A system of nine coupled nonlinear equations is developed that describe the processes of transport, degradation, and microbial growth and decay. The solution technique is highly resistant to numerical dispersion and oscillation when applied to the advection‐dispersion equation, even for large Peclet numbers (100). Microbial utilization of materials is assumed to occur by intrapore scale diffusion of materials across a diffusion boundary layer separating the particle‐bound microcolonies of bacteria from the pore fluid. Denitrifying enzyme inhibition is modeled as a function of the oxygen concentration associated with the biomass. Simulations of oxygen‐based, nitrate‐based, and multiple‐electron acceptor respiration are presented for a hypothetical experiment using kinetic parameter value estimates available from the literature.

Processes in microbial transport in the natural subsurface

“…The primary differences between these two descriptions is that the structured models have the potential to represent the influence of biofilm structure on mass transfer (both diffusion and convection within the fluid and biofilm phases) and on momentum transfer (i.e., the change in permeability due to reduction in the pore volume), whereas unstructured models do not. Typically, structured biomass models are represented as either (1) continuous biofilm on the solid surface [182,183] or (2) discontinuous patchy film [123,175,187]. As discussed by Baveye and Valocchi [142], there has been perhaps too much emphasis on making the distinction between the two kinds of models rather than focusing on the fundamental transport and reaction processes that apply to the biofilm system (the early debate regarding the appropriateness of the various conceptual models is reflected in the exchanges of [141,142,157,186]).…”

In Situ: Groundwater Bioremediation

“…These models used advective and dispersive transport coupled with an assumption of microcolonies. Widdowson et al (1988) later added nitrate respiration as an option to their model. Perhaps the best documented and most widely used model for bioremediation has been the BIOPLUME model (Borden and Bedient, 1986).…”

A brief review of bacterial transport in natural porous media

“…(1992) and Jaff6 and Taylor (1992). Typically biomass is represented as either a 1) continuous biofilm on the solid surfaces Taylor et al 1990) or 2) discontinuous patchy film (Vandevivere and Baveye 1992a,b;Rittmann 1993;Widdowson et al 1988). Also, typically no assumptions are made on biomass structure Sudicky et al 1990;Zysset et al;1994).…”