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.

Enhancing nitrogen removal efficiency and reducing nitrate liquor recirculation ratio by improving simultaneous nitrification and denitrification in integrated fixed-film activated sludge (IFAS) process

2015 ◽  
Vol 73 (4) ◽  
pp. 827-834 ◽  
Author(s):  
Yang Bai ◽  
Yaobin Zhang ◽  
Xie Quan ◽  
Shuo Chen
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Electricity Consumption ◽  
Simultaneous Nitrification And Denitrification ◽  
Recirculation Flow ◽  
Fixed Film ◽  
Gradient Gel Electrophoresis ◽  
Nitrification And Denitrification

An integrated fixed-film activated sludge (IFAS) process (G1) and an activated sludge anoxic–oxic process (G2) were operated at nitrate liquor recirculation ratio (R) of 100, 200 and 300% to investigate the feasibility of enhancing nitrogen removal efficiency (RTN) and reducing R by improving simultaneous nitrification and denitrification (SND) in the IFAS process. The results showed that the effluent NH4+-N and total nitrogen (TN) of G1 at R of 200% were less than 1.5 and 14.5 mg/L, satisfying the Chinese discharge standard (NH4+-N < 5 mg/L; TN < 15 mg/L). However, the effluent NH4+-N and TN of G2 at R of 300% were higher than 8.5 and 15.3 mg/L. It indicated that better RTN could be achieved at a lower R in the IFAS process. The polymerase chain reaction–denaturing gradient gel electrophoresis results implied that nitrifiers and denitrifiers co-existed in one microbial community, facilitating the occurrence of SND in the aerobic reactor of G1, and the contribution of SND to TN removal efficiency ranged 15–19%, which was the main reason that the RTN was improved in the IFAS process. Therefore, the IFAS process was an effective method for improving RTN and reducing R. In practical application, this advantage of the IFAS process can decrease the electricity consumption for nitrate liquor recirculation flow, thereby saving operational costs.

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.

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.

The comparison of the diversity of activated sludge plants

1998 ◽  
Vol 37 (4-5) ◽  
pp. 71-78 ◽  
Author(s):  
Thomas P. Curtis ◽  
Noel G. Craine
Keyword(s):  
Cluster Analysis ◽  
Activated Sludge ◽  
Treatment Process ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Optimal Sampling ◽  
Bacterial Populations ◽  
Large Numbers ◽  
Probable Presence ◽  
Gradient Gel Electrophoresis ◽  
Sampling Regime

The explicit engineering of bacterial populations requires that we know which organisms perform which tasks. The comparison of the bacterial diversity of activated sludge plants may give important information about the functions of different bacteria. This difficult task may be made easier by the use of technologies based on 16S rRNA based techniques. In this study we have used denaturing gradient gel electrophoresis (DGGE) to determine the optimal sampling regime for comparative studies and used cluster analysis to show how plants may be quantitatively compared. We sought evidence of spatial, diurnal and intrasample variation in a number of sites. No evidence for variation was found in the plants studied and we concluded that a single sample of an activated sludge plant was sufficient for a plant to plant comparison. The cluster analysis was able to distinguish between plants, though further work is required to find the most appropriate basis for such comparisons. We found organisms from raw sewage in the mixed liquor samples, these organisms may have no functional significance in the treatment process and thus complicate plant to plant comparisons as will the probable presence of heteroduplex rDNA products. Nevertheless we believe that these drawbacks do not outweigh the advantages of being able to take and compare relatively large numbers of samples.

Enhancing nitrogen removal efficiency in a dyestuff wastewater treatment plant with the IFFAS process: the pilot-scale and full-scale studies

2017 ◽  
Vol 77 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Yanjun Mao ◽  
Xie Quan ◽  
Huimin Zhao ◽  
Yaobin Zhang ◽  
Shuo Chen ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Full Scale ◽  
Nitrification And Denitrification ◽  
Dyestuff Wastewater

Abstract The activated sludge (AS) process is widely applied in dyestuff wastewater treatment plants (WWTPs); however, the nitrogen removal efficiency is relatively low and the effluent does not meet the indirect discharge standards before being discharged into the industrial park's WWTP. Hence it is necessary to upgrade the WWTP with more advanced technologies. Moving bed biofilm processes with suspended carriers in an aerobic tank are promising methods due to enhanced nitrification and denitrification. Herein, a pilot-scale integrated free-floating biofilm and activated sludge (IFFAS) process was employed to investigate the feasibility of enhancing nitrogen removal efficiency at different hydraulic retention times (HRTs). The results showed that the effluent chemical oxygen demand (COD), ammonium nitrate (NH4+-N) and total nitrogen (TN) concentrations of the IFFAS process were significantly lower than those of the AS process, and could meet the indirect discharge standards. PCR-DGGE and FISH results indicated that more nitrifiers and denitrifiers co-existed in the IFFAS system, promoting simultaneous nitrification and denitrification. Based on the pilot results, the IFFAS process was used to upgrade the full-scale AS process, and the effluent COD, NH4+-N and TN of the IFFAS process were 91–291 mg/L, 10.6–28.7 mg/L and 18.9–48.6 mg/L, stably meeting the indirect discharge standards and demonstrating the advantages of IFFAS in dyestuff wastewater treatment.

Degradation of Nonylphenol Polyethoxylates and its Microflora Structure in an Anoxic-Oxic Activated Sludge Process

2012 ◽  
Vol 610-613 ◽  
pp. 331-336
Author(s):  
Yuan Hua Xie ◽  
Tong Zhu ◽  
Xiao Jiang Liu ◽  
Hui Liu ◽  
Jin Han
Keyword(s):  
In Situ Hybridization ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Gel Electrophoresis ◽  
Loading Rate ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Oxygen Demand ◽  
Activated Sludge Process ◽  
Gradient Gel Electrophoresis

An anoxic-oxic activated sludge process (AOASP) was carried out to degrade nonylphenol polyethoxylates (NPEOs). The carbon source in influent was replaced stepwise by a mixture of nonylphenol decaethoxylate (M-NP10EO). The 2nd-derivative UV-spectrometry was applied to determine the total amount of M-NP10EO in water samples. Chemical oxygen demand (COD) removal efficiency achieves about 85% under the highest M-NP10EO loading rate, and M-NP10EO removal efficiency is about 80%. Denaturing gradient gel electrophoresis (DGGE) results of activated sludges show that the microbe species decrease but gradually stabilize with the increase of M-NP10EO concentration in influent. Fluorescence in situ hybridization (FISH) results of activated sludges showe that the dominant microflora under the highest M-NP10EO loading rate is β-Proteobacteria (35%), followed by α-Proteobacteria (15%), γ-Proteobacteria (5%) and Actinobateria (4%).

Are some putative glycogen accumulating organisms (GAO) in anaerobic : aerobic activated sludge systems members of the α-Proteobacteria?

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2267-2275 ◽  
Author(s):  
Michael Beer ◽  
Yun H. Kong ◽  
Robert J. Seviour
Keyword(s):  
Activated Sludge ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Bacterial Populations ◽  
Removal Capacity ◽  
Large Numbers ◽  
Gradient Gel Electrophoresis ◽  
Polyphosphate Accumulating Organisms

Activated sludge plants designed to remove phosphorus microbiologically often perform unreliably. One suggestion is that the polyphosphate-accumulating organisms (PAO) are out-competed for substrates by another group of bacteria, the glycogen-accumulating organisms (GAO) in the anaerobic zones of these processes. This study used fluorescence in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE) to analyse the communities from laboratory-scale anaerobic : aerobic sequencing batch reactors. Members of the genus Sphingomonas in the α-Proteobacteria were present in large numbers in communities with poor phosphorus removal capacity where the biomass had a high glycogen content. Their ability to store poly-β-hydroxyalkanoates anaerobically, but not aerobically, and not accumulate polyphosphate aerobically is consistent with these organisms behaving as GAO there. No evidence was found to support an important role for the γ-Proteobacteria as possible GAO in these communities, although these bacterial populations have been considered in other studies to act as possible competitors for the PAO.

Decolorization and degradation of cationic red X-GRL by upflow blanket filter

2013 ◽  
Vol 67 (5) ◽  
pp. 976-982 ◽  
Author(s):  
Bin Qiu ◽  
Yan Dang ◽  
Xiang Cheng ◽  
Dezhi Sun
Keyword(s):  
Bacterial Community ◽  
Activated Sludge ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Stable State ◽  
Oxygen Demand ◽  
Dye Wastewater ◽  
Dominant Group ◽  
Chain Reaction ◽  
Gradient Gel Electrophoresis ◽  
Polymerase Chain

An anaerobic upflow blanket filter (UBF) was employed for the treatment of dye wastewater containing cationic red X-GRL (X-GRL) in this study. The bacterial community in the UBF at its stable state was investigated by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The results showed that all color and the majority of chemical oxygen demand (COD) (92–74%) can be removed as the dye load increased from 33 to 134 g/(m3 d). The removal of color and COD were mostly attributed to the anaerobic activated sludge in the reactor. According to the DGGE fingerprints, the bacterial community in the biofilm was more diverse than that in the activated sludge. The bacterial diversity of the activated sludge and the bioflim both decreased with the dye load increasing. The dominant group was found to be phyla proteobacteria including β-proteobacteria, γ-proteobacteria, δ-proteobacteria and ɛ-proteobacteria, suggesting that these microbes might play an important role in X-GRL decolorization and degradation.

Sign in / Sign up

Export Citation Format

Share Document