Microbial community in anoxic–oxic–settling–anaerobic sludge reduction process revealed by 454 pyrosequencing analysis

2014 ◽  
Vol 60 (12) ◽  
pp. 799-809 ◽  
Author(s):  
Xinqiang Ning ◽  
Wenwen Qiao ◽  
Lei Zhang ◽  
Xu Gao
Keyword(s):  
Microbial Community ◽  
Relative Abundance ◽  
454 Pyrosequencing ◽  
Reduction Rate ◽  
Reduction Process ◽  
Anaerobic Sludge ◽  
Ammonia Oxidizing Bacteria ◽  
Sludge Reduction ◽  
Class Level ◽  
Fermentative Bacteria

Modification of the anoxic–oxic (AO) process by inserting a sludge holding tank (SHT) into the sludge return line forms an anoxic–oxic–settling–anaerobic (A+OSA) process that can achieve a 48.98% sludge reduction rate. The 454 pyrosequencing method was used to obtain the microbial communities of the AO and A+OSA processes. Results showed that the microbial community structures of the 2 processes were different as a result of the SHT insertion. Bacteria assigned to the phyla Proteobacteria and Bacteroidetes commonly existed and dominated the microbial populations of the 2 processes. However, the relative abundance of these populations shifted in the presence of SHT. The relative abundance of Proteobacteria decreased during the A+OSA process. A specific comparison at the class level showed that Sphingobacteria was enriched in the A+OSA process. The result suggested that the fermentative bacteria Sphingobacteria may have key functions in reducing the sludge from the A+OSA process. Uncultured Nitrosomonadaceae gradually became the dominant ammonia-oxidizing bacteria, and the nitrite-oxidizing bacterium Nitrospira was enriched in the A+OSA process. Both occurrences were favorable for stabilized nitrogen removal. The known denitrifying species in the A+OSA process were similar to those in the AO process; however, their relative abundance also decreased.

Microbial community structure and occurrence of diverse autotrophic ammonium oxidizing microorganisms in the anammox process

2010 ◽  
Vol 61 (11) ◽  
pp. 2723-2732 ◽  
Author(s):  
H. Bae ◽  
Y.-C. Chung ◽  
J.-Y. Jung
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Community Structure ◽  
Fragment Length Polymorphism ◽  
Amoa Gene ◽  
Continuous Operation ◽  
Anaerobic Sludge ◽  
Anammox Bacteria ◽  
Ammonia Oxidizing Bacteria ◽  
Anammox Process

The enrichment of anaerobic ammonium oxidizing (anammox) bacteria using an upflow anaerobic sludge bioreactor was successfully conducted for 400 days of continuous operation. The bacterial community structure of anammox bioreactor included Proteobacteria (42%), Chloroflexi (22%), Planctomycetes (20%), Chlorobi (7%), Bacteroidetes (5%), Acidobacteria (2%), and Actinobacteria (2%). All clones of Planctomycetes were affiliated with the anammox bacteria, Planctomycete KSU-1 (AB057453). The presence and diversity of ammonia oxidizing bacteria (AOB) and archaea (AOA) were identified by terminal restriction fragment length polymorphism (T-RFLP) based on the amoA gene sequences. The AOB in anammox bioreactor were affiliated with the Nitrosomonas europaea cluster. The T-RFLP result of AOA showed the diverse microbial community structure of AOA with three terminal restriction fragments (T-RFs).

The Research Progress on Oxic-Settling-Anaerobic Sludge Reduction Process

2013 ◽  
Vol 838-841 ◽  
pp. 2726-2734 ◽  
Author(s):  
Quan Yuan ◽  
Hai Yan Wang ◽  
Yue Xi Zhou ◽  
Hua Zhao
Keyword(s):  
Operating Performance ◽  
Reduction Process ◽  
Research Progress ◽  
Impact Factors ◽  
Anaerobic Sludge ◽  
Sludge Reduction ◽  
Reduction Mechanism ◽  
Performance Impact ◽  
Microbiological Characteristics ◽  
At Home

The research progress on the oxic-settling-anaerobic sludge reduction process at home and abroad was reviewed, which was focused on the progress of sludge reduction mechanism, operating performance, impact factors and microbiological characteristics of OSA process. Then the shortcomings of the OSA process were analyzed and its development was also predicted.

The role of (auto)catalysis in the mechanism of an anaerobic azo reduction

2000 ◽  
Vol 42 (5-6) ◽  
pp. 301-308 ◽  
Author(s):  
F.P. van der Zee ◽  
G. Lettinga ◽  
J.A. Field
Keyword(s):  
Chemical Reduction ◽  
Reduction Rate ◽  
Reduction Process ◽  
Anaerobic Sludge ◽  
Acid Orange 7 ◽  
Azo Reduction ◽  
Disulphonic Acid ◽  
Mathematical Evaluation ◽  
The Impact

Azo dyes are non-specifically reduced under anaerobic conditions, but the slow rates at which many dyes react may present a serious problem for the application of anaerobic technology as a first stage in the complete biodegradation of these compounds. Therefore, it is significant to explore the mechanism of anaerobic azo reduction, especially with respect to its kinetics. With that purpose, decolouration of the monoazo dye C.I. Acid Orange 7 (AO7) was studied in batch experiments. Experiments indicated that chemical reduction by sulphide is partially responsible for the anaerobic conversions of AO7. Mathematical evaluation of the experimental results pointed out that autocatalysis played an important role in the chemical reduction of AO7. Further tests made clear that 1-amino-2-naphthol was the dye's constituent aromatic amines that accelerated the reduction process, possibly by mediating the transfer of reducing equivalents. The impact of redox mediation by quinones was further evaluated by testingthe catalysing effects of anthraquinone-2,6-disulphonic acid (AQDS) and of autoclaved sludge. AQDS appeared to be an extremely powerful catalyst, capable of increasing the first-order chemical reduction rate constants by a factor 10 to 100. Also autoclaved sludge, possibly because of mediation by sludge organic matter, accomplished accelerated azo reduction rates. Azo reduction in living sulphidogenic anaerobic sludge environments is 3 times more rapid than the chemically catalysed reaction with sulphide. The exact role of the biological activity remains to be clarified.

Characterization of dissolved organic matter in the anoxic–oxic-settling-anaerobic sludge reduction process

2015 ◽  
Vol 259 ◽  
pp. 357-363 ◽  
Author(s):  
Zhen Zhou ◽  
Weimin Qiao ◽  
Can Xing ◽  
Chunying Wang ◽  
Lu-Man Jiang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Reduction Process ◽  
Anaerobic Sludge ◽  
Sludge Reduction

scholarly journals Microbial community with the ability to biodegradation perchlorate in a bio-electrochemical reactor

2019 ◽  
Vol 118 ◽  
pp. 01021
Author(s):  
Yu Zhong ◽  
Li He ◽  
Guangyi Fu ◽  
Youze Xu ◽  
Lixia Xie ◽  
...  
Keyword(s):  
Microbial Community ◽  
Relative Abundance ◽  
High Throughput Sequencing ◽  
Removal Rate ◽  
Electrochemical Reactor ◽  
Hunan Province ◽  
Sequencing Analysis ◽  
Initial Concentration ◽  
Perchlorate Reduction ◽  
Class Level

In this study, the sediments from the Liuyang River (Hunan Province, China) were used as an inoculum to bio-reduction perchlorate in a bio-electrochemical reactor (BER). The efficient degradation of perchlorate was found in the BER by utilizing the hydrogen as electron donor. When the current intensity was 10 mA and HRT was 72 h, the removal rate of perchlorate (initial concentration was 5 mg/L) reached 84.13% and a removal flux of 178.68 mg/m2·d was achieved. High-throughput sequencing analysis confirmed that the biofilm in the reactor had been successfully acclimated, and the system could achieve perchlorate reduction effectively. Firmicutes and Bacteroidetes were the dominant phyla during inoculation phase, and Actinobacteriria, Proteobacteria, and Tenericutes also constituted a low proportion in the biofilm. Bacilli and Clostridia were dominant at class-level both in inoculum and biofilm, with the relative abundance about 56%-72% and 17%-23%, respectively. These results confirmed that the biofilm in the BER system had been successfully formed, and the BER system could biodegradation perchlorate effectively.

scholarly journals Reduction Mechanism of Fine Hematite Ore Particles in Suspension

2021 ◽  
Author(s):  
Zhiyuan Chen ◽  
Christiaan Zeilstra ◽  
Jan van der Stel ◽  
Jilt Sietsma ◽  
Yongxiang Yang
Keyword(s):  
Particle Size ◽  
Temperature Drop ◽  
Reduction Rate ◽  
Reduction Process ◽  
Reciprocal Relationship ◽  
Drop Tube ◽  
Surface Nucleation ◽  
Order Of Magnitude ◽  
Relationship Of ◽  
Kinetics Of

AbstractIn order to understand the pre-reduction behaviour of fine hematite particles in the HIsarna process, change of morphology, phase and crystallography during the reduction were investigated in the high temperature drop tube furnace. Polycrystalline magnetite shell formed within 200 ms during the reduction. The grain size of the magnetite is in the order of magnitude of 10 µm. Lath magnetite was observed in the partly reduced samples. The grain boundary of magnetite was reduced to molten FeO firstly, and then the particle turned to be a droplet. The Johnson-Mehl-Avrami-Kolmogorov model is proposed to describe the kinetics of the reduction process. Both bulk and surface nucleation occurred during the reduction, which leads to the effect of size on the reduction rate in the nucleation and growth process. As a result, the reduction rate constant of hematite particles increases with the increasing particle size until 85 µm. It then decreases with a reciprocal relationship of the particle size above 85 µm.

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