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In this article，the high performance Polyvinylidene fluoride(PVDF)flat-sheet membrane bio-reactor (MBR)modules for small plant were developed.Main features of these MBR modules are 1)Small height，less than 1500 mm.2)Maintenance saving.3)Good filterability,which Can achieve the high net operating flux more than 0.75 m/day (=3l LMH)as net Value.Firstly.the MF membrane specialized for MBR was developed.This MF membrane is made of PVDF with high chemical resistance and mechanical strength.and it has extremely porous and smooth surface with small and narrow size distribution to achieve high flux and the low.fouling properties.Secondly,we adopted the fine bubble diffuser for the efficient aeration of the membrane surface to save the maintenance and the operation cost for the additional biological treatment.Based on our field test experience.it was confirmed that the combination of the fine bubble aeration with using the fine bubble diffuser and the newly developed smooth MF membrane could prevent the sludge onto the membrane surface very effectively.The MBR block structure was hydrodynamically optimized the circulation of aeration and water flow，which enabled the stable filtration.The total height of this module could be reduced to 1，474mm，and MBR system could be operated at 1.700 nlin depth of water,which enabled MBR system to apply tO the small water treatment plant much easier.Thirdly，we examined this new MBR module at the pilot test for sewage treatment consisting of the anoxic unit and aerobic unit(with MBR module inside)in order to ensure the excellent MBR performance. As a result，the high membrane performance，which was remarkably high flux at 1.0 m/day(=42 LMH)and stable trans-membrane pressure(TMP)，less than 0.05 kPa/day increase，was observed.It could be concluded that the newly developed small height MBR modules combined with the smooth-surface membranes and the fine bubble diffusers achieved good performance were suitable for application to small water treatmentplants.