Study On Improving Membrane Filtration Characteristics Of Membrane Bioreactor By Electrocoagulation

Membrane biological reactor (MBR) is a new, highly effective biological treatment technology, but the membrane fouling has become the main obstacle to the promotion of MBR. This study set up a new membrane biological reactor, named in situ electrocoagulation membrane biological reactor (SECMBR), which used iron plate on both sides of membrane module, in order to lessen membrane fouling.Monitor Measurement of flux, Trans-membrane pressure difference, sludge mixed liquor characteristics (EPS, SMP, Zeta potential and viscosity), membrane filtration resistance distribution of MBR, to explore the role of electrocoagulation in membrane filtration characteristics.Firstly, the effect of operation flux, aeration rate and the rate of on-off pumping is tested separately in SMBR (1-MBR) and SECMBR (2-MBR). The results show that operating flux, aerated rate, pumping stop ratio are the important factors affecting the speed of membrane fouling. Membrane fouling can be contronled effectively with low operating flux. Increase aeration rate can boost cross-flow aeration rate on the film surface, and lessen membrane fouling. With intermittent input water can be effectively reduce the deposit in the film surface of the filter cake layer, and alleviate membrane pollution.When in the processing analog printing and dyeing wastewater, in a run of 7 consecutive days, the pollution rate of membrane in 2-MBR is lower than 1-MBR by 60.47%.In turn of Simulated domestic wastewate, in a run of 7 consecutive hours, the pollution Rate of membrane in 2-MBR is lower than 1-MBR by 66.67%. The in situ electrocoagulation membrane biological reactor shows remarkable Superiority on membrane fouling alleviation.Through the analysis of the membrane resistance distribution of two reactors, finds that internal resistance (Ri)have relatively small proportion of total resistance, while resistance in sedimentary (Rc) Accounted for 90% 90% percent. The dominant resistance of membrane pollution in the course of filtration is the resistance in sedimentary (Rc).The relationship between of sludge characteristics and the membrane pollution is inspected. The experiments show that SMP has a positive correlation with Ri, with the increase in the concentration of SMP, Ri with exponentially upward trend. It turns out a positive correlation between EPS and Rc, with the increase in the concentration of EPS, Rc exponentially increased. EPSp/EPSc also has a positive correlation with Rc. Hence, EPS is the main factors of the membrane pollution, especially the protein (EPSp). On the other hand, there is a negative correlation between Zeta potential and Ri, Rc.What’s more, EPS has a positive correlation with Zeta potential. Therefore, the sludge characteristics, such as SMP, EPS, and Zeta potential, is an important factor of membrane pollution.The concentration of EPS (polysaccharide and protein, EPSp,EPSc), SMP (polysaccharide and protein), viscosity, and the value of Zeta potential, floe particle size, are measured,in order to study the impact of electro-coagulation effected on mixed liquor characteristics in SECMBR. The results show that the floc iron oxide and ferrous hydroxide generated by hydrolysis hydrogen in the process of electro-coagulation in SECMBR,can reduce the concentration of EPS、EPSp/EPSc、 SMP、quantity of electricity of sludge and Increased particle size of sludge. What’s more, Electro coagulation can enhance the ability of resistance to impact load capacity in the system.The experimental research shows that, in situ electro coagulation membrane biological reactor can be effectively lessen membrane fouling. It works well because of two reasons. SECMBR can control the resistance in sedimentary and concentration polarization resistance by the electric field effective, and ameliorate the characteristics of sludge mixed liquor.