Research On Efficiency Of Membrane Bioreactor For Ship Domestic Sewage Treatment And Membrane Fouling Mechanism

With the increasing strengthening of the marine environment protection awareness,prevention and control of marine pollution has received more attention by many countries.Simultaneously, the International Maritime Organization (IMO) has set strict standards to theship domestic sewage treatment. Because the ship domestic sewage with characteristics oflarge fluctuations in water quality and quantity, high pollution loading and easy effect bybumping and shaking, it is difficult to reach the requirements by conventional biologicaltreatment technology. Since the membrane bioreactor (MBR) organic combined themembrane separation technology and biological treatment technology, it has merits withrespect to smaller size, stable quality of the effluent, high resistance of shock loading andautomatization. Therefore, MBR has a significant advantage in the field of ship sewagetreatment. However, membrane fouling, frequent clean, short life of membrane and highprocessing cost have been the key block in the application of MBR. So, optimizing theoperating parameters, investigating the membrane fouling mechanism and reducing the totalcosts have important significance for MBR.In the present paper, polypropylene hollow fiber membrane bioreactor was used to treatthe ship domestic sewage and the start-up of MBR, operating parameters and the foulingmechanism were investigated. The main study contents are summarized as follows:1. The starting characteristics and resistance to shock loading of MBR processing theship domestic sewage were studied and the affects of aeration intensity and suction pressureon MBR decontamination efficiency were investigated;2. The MBR decontamination efficiency of COD、NH3-N、TN、TP and turbidity weredetected;3. The internal relationship between activated sludge concentration and its compositionproperties were investigated during the MBR long term running. Moreover, changes ofextracellular polymeric substance (EPS), soluble microbial product (SMP), as well as theirsmain components polysaccharide, protein in different sludge concentrations were analysed;4. The impacts of EPS、SMP and sludge volume index (SVI) on membrane fouling wereanalysed by SPSS software. Also, the membrane fouling mechanism and correlativitybetween EPS and SMP, SVI were studied; 5. The affects on membrane flux, membrane fouling rate and the activated sludgeproperties by different aeration intensities were studied, and at the same time, the influence ofthe pollutants on membrane surface by aeration intensities were analysed;6. The affects on membrane flux, membrane fouling rate and the activated sludgeproperties by different suction pressures, as well as the changes of EPS and SMP in sludgeand the impacts on membrane fouling were investigated;7. The membrane cleaning were also investigated in this paper, and then the membranesurface characteristics, structures and elements of pollutants were studied by instrumentalanalysis, such as scanning electron microscopy(SEM), X-ray micro-analyses(EDX), fouriertransform infrared spectroscopy(FTIR), nuclear magnetic resonance(NMR), on basis of which,the membrane fouling mechanism in process of ship domestic sewage treatment was furtheranalysed.