Model-based assessment of chromate reduction and nitrate effect in a methane-based membrane biofilm reactor

Chromate contamination can pose a high risk to both the environment and public health. Previous studies have shown that CH₄-based membrane biofilm reactor (MBfR) is a promising method for chromate removal. In this study, we developed a multispecies biofilm model to study chromate reduction and its interaction with nitrate reduction in a CH₄-based MBfR. The model-simulated results were consistent with the experimental data reported in the literature. The model showed that the presence of nitrate in the influent promoted the growth of heterotrophs, while suppressing methanotrophs and chromate reducers. Moreover, it indicated that a biofilm thickness of 150 μm and an influent dissolved oxygen concentration of 0.5 mg O₂/L could improve the reactor performance by increasing the chromate removal efficiency under the simulated conditions.