Bioclogging effects on mass transport using volume averaging method in bioretention cell treating wastewater: Theories

Abstract

In bioretention cell (BRC) systems, internal clogging in the hydraulic field caused by microbial organisms growing in the nonuniform porous media can lead to the reduction of denitrification capacity. To investigate microbial effect processes, a multispecies biological field‐hydraulic coupling transport model in BRC was developed based on the average volume method (AVM) and traditional convection‐diffusion–reaction equation. This model provides a method to establish a connection between the microscale biofilm thickness and the macroscale measurement of pollutant concentration, which has been less frequently discussed in previous research. The present work differs from earlier works by explicitly smoothing the diversity and complexity of media structure by upscaling the physical quantities using the AVM. The results suggest that the model is derived for enhancing a more comprehensive understanding the relationship between the microscopic biofilm thickness and the measured concentration. It is also found that the infiltration description is required adding porosity parameter in order to have an accurate simulation of permeable phenomena under biologically growing condition.