Effects of dissolved oxygen on sludge reduction and microbial community structure in sequencing batch reactors

2019 ◽  
Vol 161 ◽  
pp. 56-65
Author(s):  
Yufeng Xu ◽  
Long Wang ◽  
Xiaofeng Yin ◽  
Shengkun Zhang ◽  
Simin Li ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Dissolved Oxygen ◽  
Microbial Community Structure ◽  
Batch Reactors ◽  
Sludge Reduction ◽  
Sequencing Batch Reactors

Microbial population dynamics of granular aerobic sequencing batch reactors during start-up and steady state periods

2010 ◽  
Vol 62 (6) ◽  
pp. 1281-1287 ◽  
Author(s):  
Y. Q. Liu ◽  
Y. H. Kong ◽  
R. Zhang ◽  
X. Zhang ◽  
F. S. Wong ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Community Structure ◽  
Steady State ◽  
Microbial Community ◽  
Microbial Community Structure ◽  
Microbial Population ◽  
Granular Sludge ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Microbial Population Dynamics

This study investigates microbial population dynamics in granular sequencing batch reactors (GSBR). The experimental results of DGGE fingerprint of sludge demonstrated that the microbial community structure of sludge shifted significantly during granulation period and nutrient removal improvement period. After reactor performance and physical characteristics of sludge reached steady state, microbial population of sludge became relatively stable. The high similarity of microbial community structure between co-existed flocculated sludge and granular sludge in GSBR at different operation phases indicated that similar microbial consortium could exist in compact aggregated form or in amorphous flocculated form. Therefore, strong selection pressure was still required to wash out flocs to maintain the stability of reactor operation. In addition, it was found that substrate type had considerable impact on microbial species selection and enrichment in granular sludge. The clone library of granular sludge showed that microbial species in divisions of α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria and Bacteroidetes existed within acetate-fed granule communities and Thauera spp. from β-Proteobacteria accounted for 49% of the total clones in the whole clone library. It is thus speculated that Thauera spp. are important for the formation of acetate-fed granules under the conditions used in this study, maintaining the integrity of granules or substrate degradation.

scholarly journals Microbial community similarity and dissimilarity inside and across full-scale activated sludge processes for simultaneous nitrification and denitrification

2020 ◽  
Vol 81 (2) ◽  
pp. 333-344
Author(s):  
Jianfeng Wen ◽  
Mark W. LeChevallier ◽  
Wendong Tao
Keyword(s):  
Microbial Community ◽  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Relative Abundance ◽  
Nitrogen Removal ◽  
Full Scale ◽  
Batch Reactors ◽  
Simultaneous Nitrification And Denitrification ◽  
Sequencing Batch Reactors ◽  
Mixed Liquor

Abstract Simultaneous nitrification and denitrification under low dissolved oxygen conditions is an energy-saving modification of the activated sludge process to achieve efficient nitrogen removal. Geographically distinct full-scale treatment plants are excellent platforms to address the links of microbial community with operating parameters. Mixed liquor samples were collected from a sequencing batch reactor plant, oxidation ditch plant, and step-feed activated sludge plant. Next-Generation Sequencing of the samples showed that the microbial communities were similar at the phylum level among the plants, being dominated by Proteobacteria. Microbial composition of functional groups was similar between the react fill and react phases of the sequencing batch reactors, among four sequencing batch reactors, and among four oxidation ditches. Nitrospira was the only identified genus of autotropic nitrifying bacteria with a relative abundance of 2.2–2.5% in the oxidation ditches and 0.4–0.7% at the other plants. Heterotrophic nitrifying–aerobic denitrifying bacteria were dominated by Dechloromonas with a relative abundance of 0.4–1.0%. Microbial community composition and nitrogen removal mechanisms were related to overall level and local zonation of dissolved oxygen, mixed liquor suspended solids concentration, nitrogen and organic loadings, and solids retention time. Low dissolved oxygen and low organic and nitrogen loadings favored growth of Nitrospira.

scholarly journals Extent of the annual Gulf of Mexico hypoxic zone influences microbial community structure

2018 ◽  
Author(s):  
Lauren Gillies Campbell ◽  
J. Cameron Thrash ◽  
Nancy N. Rabalais ◽  
Olivia U. Mason
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Gulf Of Mexico ◽  
Dissolved Oxygen ◽  
Microbial Community Structure ◽  
Rrna Gene ◽  
Hypoxic Zone ◽  
Low Do

AbstractRich geochemical datasets generated over the past 30 years have provided fine-scale resolution on the northern Gulf of Mexico (nGOM) coastal hypoxic (≤ 2 mg of O2 L-1) zone. In contrast, little is known about microbial community structure and activity in the hypoxic zone despite the implication that microbial respiration is responsible for forming low dissolved oxygen (DO) conditioXSns. Here, we hypothesized that the extent of the hypoxic zone is a driver in determining microbial community structure, and in particular, the abundance of ammonia-oxidizing archaea (AOA). Samples collected across the shelf for two consecutive hypoxic seasons in July 2013 and 2014 were analyzed using 16S rRNA gene sequencing, oligotyping, microbial co-occurrence analysis and quantification of thaumarchaeal 16S rRNA and archaeal ammonia-monooxygenase (amoA) genes. In 2014 Thaumarchaeota were enriched and inversely correlated with DO while Cyanobacteria, Acidimicrobiia and Proteobacteria where more abundant in oxic samples compared to hypoxic. Oligotyping analysis of Nitrosopumilus 16S rRNA gene sequences revealed that one oligotype was significantly inversely correlated with dissolved oxygen (DO) in both years and that low DO concentrations, and the high Thaumarchaeota abundances, influenced microbial co-occurrence patterns. Taken together, the data demonstrated that the extent of hypoxic conditions could potentially influence patterns in microbial community structure, with two years of data revealing that the annual nGOM hypoxic zone is emerging as a low DO adapted AOA hotspot.

Effects of bioporous carriers on the performance and microbial community structure in side-stream anaerobic membrane bioreactors

2020 ◽  
Vol 66 (8) ◽  
pp. 475-489 ◽  
Author(s):  
Bin Zhang ◽  
Jiao Yue ◽  
Yu Guo ◽  
Taixin Liu ◽  
Min Zhou ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Community Structure ◽  
Oxygen Demand ◽  
Illumina Miseq ◽  
Membrane Bioreactors ◽  
Pollutant Removal ◽  
Sludge Reduction ◽  
Porous Carrier ◽  
Side Stream

The aim of this study was to investigate the effects of a volcanic rock porous carrier (VRPC) on sludge reduction, pollutant removal, and microbial community structure in an anaerobic side-stream reactor (ASSR). Three lab-scale membrane bioreactors (MBRs), including an anoxic–oxic MBR, which served as the control (C-MBR), an ASSR-coupled MBR (A-MBR), and an A-MBR filled with VRPC (FA-MBR) were stably and simultaneously operated for 120 days. The effect of the three reactors on the removal of chemical oxygen demand (COD) was almost negligible (all greater than 95%), but the average removal efficiency of ammonium nitrogen, total nitrogen, and total phosphorus was significantly improved by the insertion of an ASSR, especially when the ASSR was filled with VRPC. Finally, A-MBR and FA-MBR achieved 16.2% and 26.4% sludge reduction rates, with observed sludge yields of 0.124 and 0.109 g mixed liquid suspended solids/g COD, respectively. Illumina MiSeq sequencing revealed that microbial diversity and richness were highest in the VRPC, indicating that a large number of microorganisms formed on the carrier surface in the form of a biofilm. Abundant denitrifying bacteria (Azospira, Comamonadaceae_unclassified, and Flavobacterium) were immobilized on the carrier biofilm, which contributed to increased nitrogen removal. The addition of a VRPC to the ASSR successfully immobilized abundant hydrolytic, fermentative, and slow-growing microorganisms, which all contributed to reductions in sludge yield.

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