Fouling characteristics and enhancement mechanisms in a submerged flat-sheet membrane bioreactor equipped with micro-channel turbulence promoters with micro-pores

• Investigate the effect of corrugated MCTP-MPs on membrane fouling characteristics.
• Analyze the enhancement mechanisms of the corrugated MCTP-MPs.
• Micro-channels make the particles be easily trapped by adsorption and bridging.
• Micro-pores increase the effective membrane area and form an anaerobic environment.

The aim of the present research is to investigate the effect of a corrugated micro-channel turbulence promoter with micro-pores (MCTP-MPs) on the fouling characteristics of a submerged flat-sheet membrane bioreactor and analyze the enhancement mechanisms of the corrugated MCTP-MPs. The characteristics of membrane foulants are critically examined by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and energy-diffusive X-ray spectroscopy (EDS). The results demonstrated that the thickness of the cake layer was diminished, the contents of organic and inorganic foulants of SMBR equipped with MCTP-MPs were reduced, and the cake layer was more easily removed by hydraulic conditions, thereby decreasing membrane fouling compared with using a traditional membrane bioreactor. The use of an array of corrugated MCTP-MPs in SMBR caused frequent changes in flow directions and generated small eddies and a velocity gradient in the vicinity of the corrugated protrusions, which resulted in particle collisions and homodromous flocculation. In particular, when wastewater flowed past the micro-channel, the particles were easily trapped by adsorption and bridging of corrugated MCTP-MPs, therefore inhibiting the formation of the cake layer and reducing membrane pore clogging. Micro-pores could increase the effective membrane area and form an anaerobic environment to remove pollutants.