Membrane fouling limits the effects of long-term stable operation of membrane bioreactor （MBR）. Control of membrane fouling can extend the membrane life and reduce water treatment cost effectively. A pilot scale ano...Membrane fouling limits the effects of long-term stable operation of membrane bioreactor （MBR）. Control of membrane fouling can extend the membrane life and reduce water treatment cost effectively. A pilot scale anoxic/aerobic-membrane bioreactor （A/O- MBR, 40 L/hr） was used to treat the hyperhaline municipal sewage from a processing zone of Tianjin, China. Impact factors including mixed liquid sludge suspension （MLSS）, sludge viscosity （Ix）, microorganisms, extracellular polymeric substances （EPS）, aeration intensity and suction/suspended time on membrane fouling and pollution control were studied. The relationships among various factors associated with membrane fouling were analyzed. Results showed that there was a positive correlation among MLSS, sludge viscosity and trans-membrane pressure （TMP）. Considering water treatment efficiency and stable operation of the membrane module, MLSS of 5 g/L was suggested for the process. There was a same trend among EPS, sludge viscosity and TMP. Numbers and species of microorganisms affected membrane fouling. Either too high or too low aeration intensity was not conducive to membrane fouling control. Aeration intensity of 1.0 m3/hr （gas/water ratio of 25：1） is suggested for the process. A long suction time caused a rapid increase in membrane resistance. However, long suspended time cannot prevent the increase of membrane resistance effectively even though a suspended time was necessary for scale off particles from the membrane surface. The suction/suspended time of 12 min/3 rain was selected for the process. The interaction of various environmental factors and operation conditions must be considered synthetically.展开更多
Anoxic gas recirculation system was applied to control the membrane fouling in pilot-scale 4- stage anoxic membrane bioreactor （MBR）. In the anaerobic-anoxic-anoxic-aerobic flow scheme, hydrophilic polytetrafluoroet...Anoxic gas recirculation system was applied to control the membrane fouling in pilot-scale 4- stage anoxic membrane bioreactor （MBR）. In the anaerobic-anoxic-anoxic-aerobic flow scheme, hydrophilic polytetrafluoroethylene （PTFE） membrane （0.2 μm, 7.2 m2/module） was submerged in the second anoxic zone. During 8 months operation, the average flux of the membrane was 21.3 L/（m2.hr）. Chemical cleaning of the membrane was conducted only once with sodium hydroxide and sodium hypochlorite. Dissolved oxygen （DO） concentration in the second anoxic zone was maintained with an average of 0.19 ± 0.05 mg/L. Gas chromatography analysis showed that the headspace gas in the second anoxic reactor was mainly consisted of N2 （93.0% ± 2.5%）, O2 （3.8% ± 0.6%）, and CO2 （3.0% ± 0.5%）, where the saturation DO concentration in liquid phase was 1.57 mg/L. Atmospheric 02 content （20.5% ± 0.8%） was significantly reduced in the anoxic gas. The average pH in the reactor was 7.2 ± 0.4. As a result, the recirculation of the anoxic gas was successfully applied to control the membrane fouling in the anoxic MBR.展开更多
本研究采用前置缺氧/好氧膜生物反应器(Anoxic/Oxic M em brane Bioreactor,A O M B R)处理废水,分别对N H4+-N及总氮(TN)的去除效果、硝化/反硝化能力以及影响因素进行了研究。试验结果表明:在碳源充足、水力停留时间(H RT)为6.5h、污...本研究采用前置缺氧/好氧膜生物反应器(Anoxic/Oxic M em brane Bioreactor,A O M B R)处理废水,分别对N H4+-N及总氮(TN)的去除效果、硝化/反硝化能力以及影响因素进行了研究。试验结果表明:在碳源充足、水力停留时间(H RT)为6.5h、污泥泥龄(SRT)为30d、pH值范围为7.0～8.5条件下,进水N H4+-N平均值为240m g/L时,反应器能够保持良好的硝化、反硝化能力,出水N H4+-N值能稳定在2.5m g/L左右,平均去除率为98.5%,TN平均去除率为65%。展开更多
基金supported by the Special Projects of Major National Science and Technology of China (No. 2008ZX07314-003)the National Natural Science Foundation of China (No. 50708063)
文摘Membrane fouling limits the effects of long-term stable operation of membrane bioreactor （MBR）. Control of membrane fouling can extend the membrane life and reduce water treatment cost effectively. A pilot scale anoxic/aerobic-membrane bioreactor （A/O- MBR, 40 L/hr） was used to treat the hyperhaline municipal sewage from a processing zone of Tianjin, China. Impact factors including mixed liquid sludge suspension （MLSS）, sludge viscosity （Ix）, microorganisms, extracellular polymeric substances （EPS）, aeration intensity and suction/suspended time on membrane fouling and pollution control were studied. The relationships among various factors associated with membrane fouling were analyzed. Results showed that there was a positive correlation among MLSS, sludge viscosity and trans-membrane pressure （TMP）. Considering water treatment efficiency and stable operation of the membrane module, MLSS of 5 g/L was suggested for the process. There was a same trend among EPS, sludge viscosity and TMP. Numbers and species of microorganisms affected membrane fouling. Either too high or too low aeration intensity was not conducive to membrane fouling control. Aeration intensity of 1.0 m3/hr （gas/water ratio of 25：1） is suggested for the process. A long suction time caused a rapid increase in membrane resistance. However, long suspended time cannot prevent the increase of membrane resistance effectively even though a suspended time was necessary for scale off particles from the membrane surface. The suction/suspended time of 12 min/3 rain was selected for the process. The interaction of various environmental factors and operation conditions must be considered synthetically.
文摘Anoxic gas recirculation system was applied to control the membrane fouling in pilot-scale 4- stage anoxic membrane bioreactor （MBR）. In the anaerobic-anoxic-anoxic-aerobic flow scheme, hydrophilic polytetrafluoroethylene （PTFE） membrane （0.2 μm, 7.2 m2/module） was submerged in the second anoxic zone. During 8 months operation, the average flux of the membrane was 21.3 L/（m2.hr）. Chemical cleaning of the membrane was conducted only once with sodium hydroxide and sodium hypochlorite. Dissolved oxygen （DO） concentration in the second anoxic zone was maintained with an average of 0.19 ± 0.05 mg/L. Gas chromatography analysis showed that the headspace gas in the second anoxic reactor was mainly consisted of N2 （93.0% ± 2.5%）, O2 （3.8% ± 0.6%）, and CO2 （3.0% ± 0.5%）, where the saturation DO concentration in liquid phase was 1.57 mg/L. Atmospheric 02 content （20.5% ± 0.8%） was significantly reduced in the anoxic gas. The average pH in the reactor was 7.2 ± 0.4. As a result, the recirculation of the anoxic gas was successfully applied to control the membrane fouling in the anoxic MBR.
文摘本研究采用前置缺氧/好氧膜生物反应器(Anoxic/Oxic M em brane Bioreactor,A O M B R)处理废水,分别对N H4+-N及总氮(TN)的去除效果、硝化/反硝化能力以及影响因素进行了研究。试验结果表明:在碳源充足、水力停留时间(H RT)为6.5h、污泥泥龄(SRT)为30d、pH值范围为7.0～8.5条件下,进水N H4+-N平均值为240m g/L时,反应器能够保持良好的硝化、反硝化能力,出水N H4+-N值能稳定在2.5m g/L左右,平均去除率为98.5%,TN平均去除率为65%。
