Membrane Fouling Control In U-typed Hollow Fiber Membrane Bioreactors

MBR (membrane bioreactor, MBR) is a high separation efficiency of water treatment technology, with the advantages of highly removing efficiency, stable water quality, management and operation simple and low area. However, the increased operating costs andinconvenience due to the membrane fouling, which restricts the application of MBR. Through the study of membrane fouling, looking to improve and controllingmembrane fouling, maintaining the stability of the membrane flux, becoming MBR focus of the study. In this study, two-phase flow, the flocculant is added to optimize the operating conditions and other measures to improve the properties of the mixture, thus delaying the membrane fouling. By optimizing the aeration conditions, two-phase flow membrane structure and other factors effect on membrane fouling controlling, adding flocculants improve the biochemical and physicochemical properties of activated sludge mixture, thereby improving the membrane fouling, seeking the ideal type and flocculants add range and try a variety of membrane cleaning methods to get the best cleaning compositions.Studied the membrane fouling controlling in U-typed hollow fiber membrane bioreactorsexperiment with different concentration of activated sludge aeration intensity, aeration, membrane structures, stop ratio other factors influence on membrane fouling. By selecting the best test membrane inner diameter of 46mm, combined with aeration strength tests to finalize the aeration intensity of 70 L/(m2·h), selecting the best pump/stop time of 7min/3min.Experiment with different flocculant affect sludge dewatering performance, access to add variety and scope of flocculant added; study in continuous operation test MBR flocculant effect on membrane fouling controlling; flocculant is added after the experimental analysis, terms of average particle size of the activated sludge floc, EPS content, the supernatant COD, the mixture viscosity analyzes of membrane fouling control mechanism.Trial compared brush scrubbing, hypochlorite cleaning, sodium citrate cleaning and ultrasonic cleaning four different ways, and different combinations. Initial operational phase in the MBR, brush scrubbing is the most direct and effective way of cleaning, you can remove the sediment adsorption membrane surface, making flux greater degree of recovery. MBR running time increases, the effect of the gradual deterioration of brush scrubbing, flux recovery rate decreases. In this case the use of hypochlorite cleaning and brush scrubbing, flux has been significantly restored. Final selection ultrasonic cleaning after using hypochlorite cleaning, so that the flux can almost completely restored, to achieve optimal results.