Study on the Tortuosity of the Extracellular Mass Transfer Passageway in Biofilms

摘要

Two-dimensional micro-structure model of biofilms was reconstructed based on the Monte-Carlo method to simulate the mass transport in biofilm. This kind of biofilm consisted of two phases, including microbial phase (M phase) and intercellular phase (IS phase), and was established according to the average porosity of biofilm and the agglomerate coefficient of microbial clusters. The effects of average porosity and the agglomerate coefficient of microbial clusters on mass transport resistance in biofilms were studied by connecting the average porosity and the agglomerate coefficient of microbial clusters with the tortuosity of the extracellular mass transfer passageway in biofilms. The results showed that with the increase of average porosity, the tortuosity of the extracellular mass transfer passageway in biofilms decreased, and then mass transport resistance in the extracellular mass transfer passageway of biofilms decreased with the decrease of its tortuosity, that is mass diffusion coefficient increased with the increase of average porosity. In addition, with increase of the agglomerate coefficient of microbial clusters in biofilms, the tortuosity of the extracellular mass transfer passageway in biofilms also decreased, and then mass transport resistance in the extracellular mass transfer passageway of biofilms also decreased, that is mass diffusion coefficient increased with the increase of the agglomerate coefficient of microbial clusters in biofilms.