Structure Analysis of Aerobic Granule from a Sequencing Batch Reactor for Organic Matter and Ammonia Nitrogen Removal

International Journal of Environmental Research and Public Health

Jun Li¹  Ang Cai²  Danjun Wang²  Chao Chen² 

[1] College of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou 310014, China;

关键词: aerobic granules;    structure;    freezing microtome;    dissolved oxygen;    microelectrode;    CLSM;   

DOI  :  10.3390/ijerph110302427

来源: mdpi

【 摘 要 】

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.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.