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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.

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Microscopic examination of sludge and granules (scale bar = 1 mm). (a) Inoculum (floc sludge); (b) Aerobic granules at the 135th day.
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ijerph-11-02427-f003: Microscopic examination of sludge and granules (scale bar = 1 mm). (a) Inoculum (floc sludge); (b) Aerobic granules at the 135th day.

Mentions: Figure 2b shows the variation of COD, ammonia nitrogen, nitrite and nitrate in a typical SBR operation cycle. It indicates ammonia nitrogen deficit was after COD deficit. COD and ammonia removal rate were about 94% and 99%, respectively. Figure 3 shows two pictures of the inoculated activated sludge and aerobic granules by optic microscopy. It indicated that the granules had a smooth, dense and uniform surface 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)

Microscopic examination of sludge and granules (scale bar = 1 mm). (a) Inoculum (floc sludge); (b) Aerobic granules at the 135th day.
© Copyright Policy
Related In: Results  -  Collection

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

ijerph-11-02427-f003: Microscopic examination of sludge and granules (scale bar = 1 mm). (a) Inoculum (floc sludge); (b) Aerobic granules at the 135th day.
Mentions: Figure 2b shows the variation of COD, ammonia nitrogen, nitrite and nitrate in a typical SBR operation cycle. It indicates ammonia nitrogen deficit was after COD deficit. COD and ammonia removal rate were about 94% and 99%, respectively. Figure 3 shows two pictures of the inoculated activated sludge and aerobic granules by optic microscopy. It indicated that the granules had a smooth, dense and uniform surface 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