A dual flowing continuum approach to model denitrification experiments in porous media colonized by biofilms

Global sensitivity analysis and Bayesian parameter inference for solute transport in porous media colonized by biofilms

“…Unfortunately, actual observations such as concentrations at the outlet of a column or sampled at some locations in aquifers do not distinguish C p and C b . For example, in laboratory column experiments as those simulated hereafter, what can be reasonably measured is a flux-averaged concentration at the column output (see e.g., actual experiments in Delay et al, 2013) in the form:…”

“…A dual flowing continuum approach was proposed by Delay et al (2013) to simulate laboratory experiments of mass transfer in a porous medium colonized by a biofilm. The concept was shown to be appropriate in the case of widely colonized media, as the single continuum approach led to unphysical results with inferred dispersivity values larger than the size of the modeled system (Delay et al, 2013).…”

“…The concept was shown to be appropriate in the case of widely colonized media, as the single continuum approach led to unphysical results with inferred dispersivity values larger than the size of the modeled system (Delay et al, 2013). The main characteristic of the dual flowing continuum is to convey the solute by advection-dispersion in both the porous and the biofilm phases, each phase being assigned with specific transport properties.…”

“…Furthermore, according to Delay et al (2013), the kinetic rate of mass transfer between the two flowing continua deeply impacts the shape of the solute breakthrough curves which in turn can modify the model behavior and the identifiability of the model parameters. To investigate this effect, two contrasted flowing scenarios are considered in this study.…”

“…These scenarios manipulate synthetic data drawn from numerical simulations to avoid the addition of uncontrolled noise from actual experiments that could bias conclusions. However, these scenarios are based on actual experiments (reported in Delay et al, 2013) performed in large laboratory columns and developed to address the feasibility of a water decontamination (denitrification) plant in the field. Both scenarios deal with the injection of a conservative tracer in a porous medium colonized by a stationary biofilm phase.…”