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The settling characteristics and mean settling velocity of granular sludge in upflow anaerobic sludge blanket (UASB)-like reactors

Biotechnology Letters volume 28, pages 1673–1678 (2006)Cite this article

Abstract

Mean settling velocity of granular sludge in full-scale UASB (upflow anaerobic sludge blanket) and EGSB (expanded granular sludge bed) reactors was evaluated by settling column tests, and a settling velocity model based on the experimental results and available literature data was developed. It is concluded that the settling velocity should be calculated by the Allen formula, because the settling process of the granules is in the category of intermediate flow regime rather than in the laminar flow one. The comparison between calculated and measured values of the settling velocity shows an excellent agreement, with an average relative error of 4.04%. A simple but reliable mathematical method to determine the settling velocity is therefore proposed.

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Abbreviations

d p :

mean granule diameter by wet sieving, mm

g :

gravitational acceleration, m s−2

Re t :

Reynolds number at terminal velocity

u t :

mean settling velocity of the granules, m h−1

μ :

the fluid viscosity, Pa. s

ρ :

the density of wastewater, kg m−3

ρ p :

the density of the granules, kg m−3

ξ :

drag coefficient

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Acknowledgement

This study was financed by National 863 RD Program under grant No. 2002AA601190.China.

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Affiliations

  1. Department of Environmental Engineering, Xi’an Jiaotong University, Xi’an, 710049, China

    Yong-hong Liu, Yan-ling He & Shu-cheng Yang

  2. Department of Environmental Engineering, Xi’an University of Engineering and Technology, Xi’an, 710048, China

    Yong-hong Liu

  3. Institute of Environmental Science & Engineering, Nanyang Technological University, Singapore, 637723, Singapore

    Yao-zhong Li

Authors
  1. Yong-hong Liu
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  2. Yan-ling He
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  3. Shu-cheng Yang
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  4. Yao-zhong Li
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Correspondence to Yong-hong Liu.

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Liu, Yh., He, Yl., Yang, Sc. et al. The settling characteristics and mean settling velocity of granular sludge in upflow anaerobic sludge blanket (UASB)-like reactors. Biotechnol Lett 28, 1673–1678 (2006). https://doi.org/10.1007/s10529-006-9136-1

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  • DOI: https://doi.org/10.1007/s10529-006-9136-1

Keywords

  • Aaerobic granular sludge
  • Intermediate flow regime
  • Mean settling velocity
  • UASB-like reactor
  • Wastewater treatment