Comparison of nitrification performance and microbial community between submerged membrane bioreactor and conventional activated sludge system

2005 ◽  
Vol 51 (6-7) ◽  
pp. 193-200 ◽  
Author(s):  
H. Li ◽  
M. Yang ◽  
Y. Zhang ◽  
X. Liu ◽  
M. Gao ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Heterotrophic Bacteria ◽  
Nitrite Oxidation ◽  
Submerged Membrane Bioreactor ◽  
Conventional Activated Sludge ◽  
Activated Sludge System ◽  
Gradient Gel Electrophoresis

A submerged membrane bioreactor (SMBR) and a conventional activated sludge system (CAS) were compared in parallel over a period of more than 260 days on treating synthetic ammonia-bearing inorganic wastewater without sludge purge under decreased hydraulic retention times (HRTs). Conversion of NH4+-N to NO3--N was achieved with an efficiency of over 98% at an HRT ≥ 10 h in the SMBR, while similar performance was obtained at an HRT ≥ 20 h in the CAS. Denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR) amplified 16S rDNA was used to monitor variations of community structures in the two systems. With the prolongation of operation, the number of DGGE bands in the SMBR gradually increased from the initial 11 bands to the final 22 bands, whereas that in the CAS varied in a range between 13 and 183 Sequence analysis indicates that Nitrosomonas sp. and Nitrospira sp. were the dominating nitrification species responsible for ammonia and nitrite oxidation, respectively. Heterotrophic bacteria like Pseudomonas sp. and Flavobacteria sp. existed in both of the systems although only inorganic wastewater was fed. Substantive accumulation of extracellular polymeric substances (EPS) in the SMBR was confirmed by scanning electron microscopy and EPS analysis.

Integration of nitrification and denitrification by combining anoxic and aerobic conditions in a membrane bioreactor

2010 ◽  
Vol 62 (11) ◽  
pp. 2590-2598 ◽  
Author(s):  
Jianfeng Li ◽  
Fenglin Yang ◽  
Dieudonné-Guy Ohandja ◽  
Fook-Sin Wong
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Membrane Bioreactor ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Biomass Concentration ◽  
Morphological Properties ◽  
Utilization Rate ◽  
Gradient Gel Electrophoresis ◽  
Microbial Characterization ◽  
Nitrification And Denitrification

A membrane bioreactor (MBR) was developed to achieve nitrogen removal by combining nitrification and denitrification conditions in one reactor. The activated sludge was alternated between aerobic and anoxic conditions using peristaltic pump. The biomass concentration and floc morphological properties were observed to be similar in anoxic and aerobic compartments. However, the homogeneous properties of the activated sludge did not lead to the failure of oxygen gradient formation in the reactor. Due to the position of the air diffuser, an anoxic compartment at the bottom and an aerobic compartment in the upper part of the reactor were formed after 40 days. The average total nitrogen (TN) removal efficiency was then observed to increase to 77%. The microbial characterization using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis, as well as the specific nitrogen utilization rate measurements, indicated that the nitrogen removal in the reactor occurred via nitrification and denitrification processes.

Analysis of Bacterial Communities in A2O Membrane Bioreactor Treating Oily Wastewater

2013 ◽  
Vol 641-642 ◽  
pp. 87-91 ◽  
Author(s):  
Zheng Hua Duan ◽  
Liu Ming Pan ◽  
Hua Wang ◽  
Ning Tao Li
Keyword(s):  
Activated Sludge ◽  
Bacterial Communities ◽  
Membrane Bioreactor ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Membrane Separation ◽  
Diversity Index ◽  
Oily Wastewater ◽  
Wastewater Purification ◽  
Gradient Gel Electrophoresis ◽  
Dominant Bacteria

To improve the efficiency of oily wastewater purification, a laboratory-scale anaerobic/anoxic/aerobic (A2O) membrane bioreactor was designed to treat the oily wastewater based on the conventional A2O activated sludge process and membrane separation technology, and the variation of bacterial community structure in the activated sludge of key reactors were investigated by PCR-DGGE (denaturing gradient gel electrophoresis). The result of Shannon diversity index comparing indicated that MBR seemed to be more constant than the A/0 system. Four sensitive dominant bacteria were verified in the treatment of oily wastewater. They were Uncultured Comamonadaceae bacterium, Hydrogenophaga sp., uncultured beta proteobacterium, and uncultured Thiobacillus sp. It suggested that PCR-DGGE can be used as an effective supplementary method for verifying cultural dominant microorganisms in activated sludge of oily wastewater.

Membrane bioreactor versus conventional activated sludge system: population dynamics of nitrifiers

2005 ◽  
Vol 52 (10-11) ◽  
pp. 417-425 ◽  
Author(s):  
R. Manser ◽  
W. Gujer ◽  
H. Siegrist
Keyword(s):  
Activated Sludge ◽  
Community Composition ◽  
Membrane Bioreactor ◽  
Membrane Separation ◽  
Heterotrophic Bacteria ◽  
Microbial Community Composition ◽  
Laser Scanning Microscopy ◽  
Nitrifying Bacteria ◽  
Ammonia Oxidizing Bacteria ◽  
Conventional Activated Sludge

Although membrane bioreactors have attracted increasing attention in recent years, little research has been undertaken on the influence of the membrane separation on the microbial community composition. This paper compares the startup behaviour and the performance of the subsequent eight months of a membrane bioreactor with a conventional activated sludge pilot plant. Both plants were operated in parallel at the same sludge age and treated the same domestic wastewater. The identification of the nitrifying community composition using fluorescent in situ hybridization revealed only minor differences between the two reactors for both ammonia-oxidizing bacteria and nitrite-oxidizing bacteria. Accordingly, both systems exhibited the same maximum nitrification rates. Confocal laser scanning microscopy showed that the aggregates formed by nitrifying bacteria were located mostly in the inner part of the flocs and were overgrown by heterotrophic bacteria. It is concluded that the membrane separation itself does affect neither the nitrifying community composition nor the nitrification performance. However, impacts on kinetic parameters are emphasized.

Effect of Suspended Carriers on Extracellular Polymeric Substances in MBR

2014 ◽  
Vol 955-959 ◽  
pp. 1939-1943
Author(s):  
Chun Hua Zhang ◽  
Xiao Xia Ou ◽  
Feng Jie Zhang
Keyword(s):  
Activated Sludge ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Aeration Rate ◽  
Woven Fabric ◽  
Membrane Model ◽  
Synthetic Wastewater ◽  
Model Surface ◽  
Submerged Membrane Bioreactor

Suspended carriers were added into a submerged membrane bioreactor (SMBR) using polypropylene non-woven fabric (PP NWF) as membrane model to treat synthetic wastewater. The changes of EPSSEPSB and EPS in activated sludge mixing liquid of MBR and in sludge on membrane model surface were researched at different aeration rate. The results showed that adding suspended carriers in MBR can increase the concentration of EPSS and EPSB in activated sludge mixing liquid, but the effect on EPSS and EPSB in the sludge on membrane model surface is related to aeration rate. Adding suspended carriers can increase the concentration of EPSS and EPSB in the sludge on membrane model surface at 0.10m3/h of aeration rate; the concentration of EPSS and EPSB in the sludge with suspended carriers is reduced when aeration rate is increased to 0.25m3/h. The study on the effect of aeration rate on EPS in sludge mixing liquid of MBR and in sludge on membrane model surface showed that an optimized aeration rate exists if suspended carriers are added to control MBR membrane fouling. At the optimized aeration rate, membrane fouling can be mitigated and controled effectively.

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