Simultaneous carbon and nitrogen removals in membrane bioreactor with mesh filter: An experimental and modeling approach

• An MBR with a mesh filter was developed for carbon and nitrogen removals.
• The intermittently aerated MBR showed high COD and nitrogen removal efficiencies.
• A model was developed for process simulation and results agreed with the data well.
• The removal efficiencies can be improved by process optimization using the model.

In this study, an intermittently aerated Membrane bioreactors (MBR) with stainless steel mesh as filter was developed for simultaneous effective carbon and nitrogen removals. The biofilm attached on mesh filter can effectively reject suspended solids to improve effluent quality. The chemical oxygen demand (COD) and nitrogen removal efficiencies of the system were examined at different influent COD/N ratios, dissolved oxygen (DO) levels and aerobic/anoxic time ratios. The reactor achieved COD, NH4+–N and total nitrogen (TN) removals over 93.7%, 92.8% and 79.5%, respectively. To get a better insight into this process, a mechanistic mathematical model was developed based on the Activated Sludge Model No. 3 (ASM3) for the process simulation. The simulation results agreed with the measured data well. The optimization results show that an appropriate DO level in the aerobic phase and a prolonged anoxic time is required to further improve the TN removal.

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