Modeling of a foamed emulsion bioreactor: I. Model development and experimental validation

Abstract

Recently, a new type of bioreactor for air pollution control referred to as the foamed emulsion bioreactor (FEBR) has been developed. The process relies on the emulsion of an organic phase with a suspension of an actively growing culture of pollutant-degrading microorganisms, made into a foam with the air undergoing treatment. In the current paper, a diffusion and reaction model of the FEBR is presented and discussed. The model considers the fate of the volatile pollutant in the emulsion that constitutes the liquid films of the FEBR. Oxygen limitation as well as substrate inhibition were included in the biokinetic relationships. The removal of toluene vapors served for the validation of the model. All the model parameters were determined by independent experiments or taken from the literature. The model predictions were found to be in good agreement with the experimental data and the model provided useful insights on the phenomena occurring in the FEBR. Model parametric sensitivity studies and further discussion of the factors that limit the performance of the FEBR are presented in Part 2 of this paper.

Model for a solid–liquid stirred tank two-phase partitioning bioscrubber for the treatment of BTEX

“…Recently, models have been developed and validated, with the objective of predicting performance under various operating conditions, for several novel biotreatment systems of waste gases including foamed emulsion bioreactors for the treatment of toluene [1], dual liquid-phase biofilters for hydrophobic pollutants [2], hybrid bioreactors composed of a bubble column bioreactor and biofilter compartments for the treatment of benzene [3], and membrane bioreactors for the treatment of toluene [4]. A novel biotreatment system that has been shown to be very promising for the treatment of gases contaminated by benzene, toluene, ethylbenzene and o-xylene (BTEX) is the stirred tank solid-liquid two-phase partitioning bioscrubber (SL-TPPB), which has been experimentally investigated by Littlejohns and Daugulis [5].…”

“…Mathematical models for biodegradation systems used in the treatment of waste gas streams serve two purposes: (1) to explain the phenomena that are occurring within the bioreactor to achieve decontamination of the waste gas stream and (2) to predict the performance of the system under various operating conditions. Recently, models have been developed and validated, with the objective of predicting performance under various operating conditions, for several novel biotreatment systems of waste gases including foamed emulsion bioreactors for the treatment of toluene [1], dual liquid-phase biofilters for hydrophobic pollutants [2], hybrid bioreactors composed of a bubble column bioreactor and biofilter compartments for the treatment of benzene [3], and membrane bioreactors for the treatment of toluene [4].…”

Modeling of a foamed emulsion bioreactor: II. model parametric sensitivity

“…The simulated toluene elimination capacity and removal efficiency are plotted in Figure 6. As discussed in Part I of this paper (Kan and Deshusses, 2008), when the gas velocity is varied, the foam characteristics are changed, and therefore the fate and transport of toluene and oxygen in the system change. However, the main effect of changing the gas velocity (at a fixed bed height) is that it changes the gas residence time in the reactor.…”

“…Note that those values were obtained from experiments and that the model does not contain any fitted parameters (Kan and Deshusses, 2008). Unless noted otherwise, the sensitivity of toluene removal to model parameters was examined using the following conditions: toluene inlet concentration of 1 g m À3 , biomass concentration of 16 g dw L…”

“…In the first part of this paper (Kan and Deshusses, 2008), a conceptual model that describes toluene fate and transport in the FEBR was presented. For modeling purpose, the FEBR was assumed to be divided into small ideally mixed subdivisions.…”