臭氧-生物活性炭-金属膜联用工艺在水处理中的应用

摘要

采用臭氧-生物活性炭(O3-BAC)-金属膜联用工艺去除水中污染物,探讨膜污染及膜清洗方法.试验结果表明,联用工艺对浊度、菌落总数、DOC的平均去除率分别为86.1％ 、96.2％、66.4％,出水颗粒总数低于100 个/mL.恒通量(2m3/m2·h)终端过滤条件下,金属膜连续过滤60 min后其跨膜压差由0 MPa升至0.7 MPa.扫描电镜观察发现小颗粒污染物堵塞膜孔、覆盖膜表面,导致膜通量下降.采用膜滤后水反冲洗污染膜4 min(0.4 MPa),膜通量恢复率为86.4％;水反冲洗后分别采用2％柠檬酸和2％氢氧化钠对污染膜进行化学浸泡,通量恢复率均高于97.0％.%Removal of pollutants in water by combined processes of ozone-biological activated carbon O3-BAC) and metallic membrane was investigated.Membrane fouling and cleaning methods were studied by authors.Results showed that average removal rate of turbidity,total bacteria and DOC by the integrated process was 86.1％,96.2％ and 66.4％,respectively.The number of particles in membrane effluent was less than 100 p/mL.For dead-end mode with constant flux (2 m3/m2 · h),the trans-membrane pressure of the metallic membrane increases from 0 MPa to 0.7 MPa after operating for 60 minutes.Scanning electron microscopy observations showed that small particles block membrane pores or cover membrane surface,thus causing membrane flux declined.Membrane flux recovery ratio was 86.4％ after backwashing by membrane effluent for 4 min (0.4 MPa).Metallic membrane was then soaked in 2％ citric acid or 2％ sodium hydroxide and the membrane flux recovery was above 97.0％.