Dynamic membrane bioreactor for wastewater treatment: Operation, critical flux, and dynamic membrane structure

•Critical flux of DM was in the range of 70–75 L/m2h in wastewater treatment.•DM at sub-critical flux exhibited longer filtration time and smaller flux decline.•PN and PS showed contrary variations from the top to bottom cake layer.•Mean particle size of DM showed hierarchical structure.•PN was the major content in the residual substances on support mesh.

This research investigated the characteristics of the dynamic membrane bioreactor (DMBR) for wastewater treatment, including operation performance, critical flux of dynamic membrane (DM), and structure of the cake layer. Various analytical methods were used. The DMBR exhibited excellent pollutant-removal efficiencies, and the critical flux of DM was in the range of 70–75 L/m2h. The DM operated at sub-critical flux exhibited longer filtration time and smaller flux decline in the filtration process. The DM formed by activated sludge exhibited a hierarchical structure, and the order of mean particle size of three cake layers was as follows: top cake layer