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Structure analysis of aerobic granule from a sequencing batch reactor for organic matter and ammonia nitrogen removal.

Li J, Cai A, Wang D, Chen C, Ni Y - Int J Environ Res Public Health (2014)

Bottom Line: The diameter, settling velocity and SVI10 of granules ranged from 2 to 5 mm, 80 to 110 m/h and about 40 mL/g, respectively.Freezing microtome images, DO concentration profiles by microelectrode, distribution of bacteria and EPS by confocal laser scanning microscopy (CLSM) show that the aerobic granules have a three-layer structure.Each layer has different thickness, character, bacteria, and DO transfer rate.

View Article: PubMed Central - PubMed

Affiliation: College of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou 310014, China. tanweilijun@zjut.edu.cn.

ABSTRACT
Aerobic granules were cultivated in a sequencing batch reactor (SBR). COD and ammonia nitrogen removal rate were 94% and 99%, respectively. The diameter, settling velocity and SVI10 of granules ranged from 2 to 5 mm, 80 to 110 m/h and about 40 mL/g, respectively. Freezing microtome images, DO concentration profiles by microelectrode, distribution of bacteria and EPS by confocal laser scanning microscopy (CLSM) show that the aerobic granules have a three-layer structure. Each layer has different thickness, character, bacteria, and DO transfer rate. A hypothesis for granule structure is proposed: the first layer, the surface of the granule, is composed mostly of heterotrophic organisms for organic matter removal, with a thickness range from 150 to 350 μm; the second layer, mostly composed of autotrophic organisms for ammonia nitrogen removal, with a thickness range from 250 to 450 μm; the third layer, located in the core of the granule, has mostly an inorganic composition and contains pores and channels.

Show MeSH
Equipotential line of DO microelectrode in the surface layer of a granule.
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ijerph-11-02427-f006: Equipotential line of DO microelectrode in the surface layer of a granule.

Mentions: Figure 6 shows the equipotential lines of the DO microelectrode in the surface layer of a granule in water. The lines at different depth match with the profile of the granule surface. It indicates the first layer had a uniform structure.


Structure analysis of aerobic granule from a sequencing batch reactor for organic matter and ammonia nitrogen removal.

Li J, Cai A, Wang D, Chen C, Ni Y - Int J Environ Res Public Health (2014)

Equipotential line of DO microelectrode in the surface layer of a granule.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3986984&req=5

ijerph-11-02427-f006: Equipotential line of DO microelectrode in the surface layer of a granule.
Mentions: Figure 6 shows the equipotential lines of the DO microelectrode in the surface layer of a granule in water. The lines at different depth match with the profile of the granule surface. It indicates the first layer had a uniform structure.

Bottom Line: The diameter, settling velocity and SVI10 of granules ranged from 2 to 5 mm, 80 to 110 m/h and about 40 mL/g, respectively.Freezing microtome images, DO concentration profiles by microelectrode, distribution of bacteria and EPS by confocal laser scanning microscopy (CLSM) show that the aerobic granules have a three-layer structure.Each layer has different thickness, character, bacteria, and DO transfer rate.

View Article: PubMed Central - PubMed

Affiliation: College of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou 310014, China. tanweilijun@zjut.edu.cn.

ABSTRACT
Aerobic granules were cultivated in a sequencing batch reactor (SBR). COD and ammonia nitrogen removal rate were 94% and 99%, respectively. The diameter, settling velocity and SVI10 of granules ranged from 2 to 5 mm, 80 to 110 m/h and about 40 mL/g, respectively. Freezing microtome images, DO concentration profiles by microelectrode, distribution of bacteria and EPS by confocal laser scanning microscopy (CLSM) show that the aerobic granules have a three-layer structure. Each layer has different thickness, character, bacteria, and DO transfer rate. A hypothesis for granule structure is proposed: the first layer, the surface of the granule, is composed mostly of heterotrophic organisms for organic matter removal, with a thickness range from 150 to 350 μm; the second layer, mostly composed of autotrophic organisms for ammonia nitrogen removal, with a thickness range from 250 to 450 μm; the third layer, located in the core of the granule, has mostly an inorganic composition and contains pores and channels.

Show MeSH