| Membrane bioreactor(MBR) is a new wastewater treatment which is the combination of the membrane separation technology and biological reactor. The membrane separation and biological treatment with membrane separation technology together, to replace the ordinary biology reactor in two sink the pond, which has a highly efficient solid-liquid separation effects and potential applications, by the national water treatment technology researchers’ attention. During operation, leading to membrane fouling membrane flux decline, increased membrane replacement and cleaning frequency, thereby increasing the operating costs of the MBR, so MBR is not currently widely used. So study the causes of membrane fouling and contamination study recovery after effects, pollution and other issues have become the key tasks in the field.This paper mainly studied the self-made composite membrane made ofcurtain membrane module into the inverted A2/O-MBR system, inversion, simulated domestic wastewater and actual sewage treatment under normal temperature, investigated the changes of properties of sludge, the removal efficiency of COD,ammonia nitrogen, total nitrogen, total phosphorus system, membrane of turbidity, TOC interception, from the macro and micro factors such as different angles on membrane fouling.And wash the control of composite membrane were studied by onlinechemistry. The results are as follows:(1) At room temperature,the removal rate of the COD ammonia, total nitrogen and total phosphorus in the wastewater through the membrane bioreactor is respectively 90%, 98%, 75% and 50%, in the simulated domestic wastewater the removal rate of the COD ammonia, total nitrogen and total phosphorus reached 95%, 98%, 54% and 20%.the effluent quality was stable. Throughout the course of the experiment, composite membrane run to 11±0.5L·m2/h for 3 months, repeated use of the chemical cleaning of the membrane, membrane wire breakage does not occur, the composite membrane has good tensile, compressive strength properties.(2) The nature of the reactor and membrane fouling sludge mixed factors were analyzed, the results showed that: Compared to simulate actual sewage sewage, its small particle size of the activated sludge, a mixture of dissolved extracellular polymer(SMP) is large, a greater impact on membrane fouling.(3)The use of atomic force microscopy measurementof adhesionbetween pollutants and film,found that the adhesion between LB-EPSfilm and EPS is the largest,followed by TB,and finally SMP. And adhesion between pollutants and contaminants is weak, indicating tha that the membrane interface and adhesion force of pollution caused by pollutants fouling behavior is the main reason(4)The NaClO on-line cleaning of the membrane, on-line cleaning of themembrane in the TMP jump before cleaning, the recovery rate of TMPreached 98%, the running time of the stage is 24 days; circulating online cleaning, the initial TMP recovery rate reached 100%, the running time is 36 days, with the increase of washing time, recovery rate decreased gradually, can effectively retard membrane fouling has entered a rapid growth stage. NaClO has a stronger effect on the removal of EPS, an increase of 20% compared to the pure water. The use of NaClO onlineafter cleaning the membrane, the membrane is clearly visible, the chemical structure of membrane remained intact. Add the mixture of low concentration of NaClO did not adversely affect the stability of membrane structure and system. |
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