To determine whether the functional stability of nitrification was correlated to a stable community structure of ammonia oxidizing bacteria(AOB)in a fullscale wastewater treatment plant,the AOB community dynamics in a...To determine whether the functional stability of nitrification was correlated to a stable community structure of ammonia oxidizing bacteria(AOB)in a fullscale wastewater treatment plant,the AOB community dynamics in a wastewater treatment system was monitored over one year.The community dynamics were investigated using specific PCR followed by terminal restriction fragment length polymorphism(T-RFLP)analysis of the amoA gene.The T-RFLP results indicated that during the period of nitrification stability,the AOB community structure in the full-scale wastewater treatment system was relatively stable,and the average change rate every 15 d of the system was 6.6%±5.8%.The phylogenetic analysis of the cloned amoA gene showed clearly that the dominant AOB in the system was Nitrosomonas spp.The results of this study indicated that throughout the study period,the AOB community structure was relatively stable in the full-scale wastewater treatment system with functional stability of nitrification.展开更多
The effect of COD/N ratio on the granulation process and microbial population succession was investigated.Four identical sequencing batch reactors,R1,R2,R3 and R4,were operated with various initial COD/N ratios rangin...The effect of COD/N ratio on the granulation process and microbial population succession was investigated.Four identical sequencing batch reactors,R1,R2,R3 and R4,were operated with various initial COD/N ratios ranging from 0/200 to 800/200（m/m）.Ethanol was fed as the source of COD.Aerobic granules were successfully cultivated in R2 and R3,operating with the COD/N ratio of 200/200 and 400/200,respectively.Scanning electron microscope observations indicated that short rod-shaped and spherical bacteria were dominant in R2,while granules produced in R3 were surrounded with a large amount of filamentous bacteria.The average specific nitritation rate in R2 and R3 were 0.019 and 0.008 mg N/（mg MLVSS.hr）,respectively.Fluorescence in situ hybridization results demonstrated that nitrifying bacteria population was enriched remarkably in R2.It indicated that nitrification ability and nitrifying bacteria population were enriched remarkably at low COD/N ratio.However,no granules were formed in R1 and R4 which might attribute to either limited or excessive extracellular polymeric substances production.This study contributed to a better understanding of the role of COD/N ratio in nitrifying sludge granulation.展开更多
基金This study was supported by the National Natural Science Foundation of China(Grant No.51078207)Mega-projects of Science Research for Water(No.2008ZX07313-3)the Program of Research on Key Technology of Environmental Pollution Control and Quality Improvement(No.2007DFC90170),and Research Fund for the Doctoral Program of Higher Education of China(No.20090002770003).
文摘To determine whether the functional stability of nitrification was correlated to a stable community structure of ammonia oxidizing bacteria(AOB)in a fullscale wastewater treatment plant,the AOB community dynamics in a wastewater treatment system was monitored over one year.The community dynamics were investigated using specific PCR followed by terminal restriction fragment length polymorphism(T-RFLP)analysis of the amoA gene.The T-RFLP results indicated that during the period of nitrification stability,the AOB community structure in the full-scale wastewater treatment system was relatively stable,and the average change rate every 15 d of the system was 6.6%±5.8%.The phylogenetic analysis of the cloned amoA gene showed clearly that the dominant AOB in the system was Nitrosomonas spp.The results of this study indicated that throughout the study period,the AOB community structure was relatively stable in the full-scale wastewater treatment system with functional stability of nitrification.
基金supported by the National Key Technologies R&D Program of China during the Eleventh Five-year Plan Period (No. 2009BAC57B01)the State Key Laboratory of Urban Water Resource and Environment(HIT) (No. QAK201006)
文摘The effect of COD/N ratio on the granulation process and microbial population succession was investigated.Four identical sequencing batch reactors,R1,R2,R3 and R4,were operated with various initial COD/N ratios ranging from 0/200 to 800/200（m/m）.Ethanol was fed as the source of COD.Aerobic granules were successfully cultivated in R2 and R3,operating with the COD/N ratio of 200/200 and 400/200,respectively.Scanning electron microscope observations indicated that short rod-shaped and spherical bacteria were dominant in R2,while granules produced in R3 were surrounded with a large amount of filamentous bacteria.The average specific nitritation rate in R2 and R3 were 0.019 and 0.008 mg N/（mg MLVSS.hr）,respectively.Fluorescence in situ hybridization results demonstrated that nitrifying bacteria population was enriched remarkably in R2.It indicated that nitrification ability and nitrifying bacteria population were enriched remarkably at low COD/N ratio.However,no granules were formed in R1 and R4 which might attribute to either limited or excessive extracellular polymeric substances production.This study contributed to a better understanding of the role of COD/N ratio in nitrifying sludge granulation.
