Influence of solid retention time on sludge characteristics and effluent quality in immersed membrane bioreactor  

作　　者：CAO ZhanPing ZHANG JingLi ZHANG HongWei 

机构地区：[1]School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China [2]Institute of Membrane Science and Technology, Tianjin Polytechnic University, Tianjin 300160, China

出　　处：《Chinese Science Bulletin》2008年第24期3942-3950,共9页

基　　金：Supported by Natural Science Foundation of Tianjin (Grant No.08JC2DJC24300)

摘　　要：Here the effect of solid retention time(SRT) on the concentration of the mixed liquor suspend solid(MLSS),the sludge characteristics,the content of extra-cellular polymeric substances(EPS),the viscosity of mixed liquor and effluent quality in the immersed membrane bioreactor(IMBR) was investi-gated.The results indicate that the increase of the EPS content is the main reason for the increase of mixed liquor viscosity,the former is positively correlated with the latter(R2 = 0.9751).The size distribution profile of particles in the mixed liquor presents double-peak shape at SRT more than 30 days.The filtration resistance of membrane in IMBR is mainly caused by the tiny particles and the viscosity of the mixed liquor.In this study,the extension of SRT can hardly affect the removal efficiency of Chemical Oxygen Demand(COD) and NH+4―N,and when SRT is below 30 days,silt density index(SDI15) is less than 3,the effluent can be deeply treated by using reverse osmosis system(RO) or nano-filtration system(NF).The method of controlling SRT is put forward by analyzing the relationship between SRT and the minimum generation-time of dominant bacteria(at the maximum specific growth rate under the operation temperature).Here the effect of solid retention time （SRT） on the concentration of the mixed liquor suspend solid （MLSS）, the sludge characteristics, the content of extra-cellular polymeric substances （EPS）, the viscosity of mixed liquor and effluent quality in the immersed membrane bioreactor （IMBR） was investigated. The results indicate that the increase of the EPS content is the main reason for the increase of mixed liquor viscosity, the former is positively correlated with the latter （R^2 = 0.9751）. The size distribution profile of particles in the mixed liquor presents double-peak shape at SRT more than 30 days. The filtration resistance of membrane in IMBR is mainly caused by the tiny particles and the viscosity of the mixed liquor. In this study, the extension of SRT can hardly affect the removal efficiency of Chemical Oxygen Demand （COD） and NH4^＋-N, and when SRT is below 30 days, silt density index （SDIIs） is less than 3, the effluent can be deeply treated by using reverse osmosis system （RO） or nano-filtration system （NF）. The method of controlling SRT is put forward by analyzing the relationship between SRT and the minimum generation-time of dominant bacteria （at the maximum specific growth rate under the operation temperature）.

关 键 词：IMBR 固体固定时间 EPS 过滤电阻 沙土密度 

分 类 号：X1[环境科学与工程—环境科学]