Characterization of nitrifying granules produced in an aerobic upflow fluidized bed reactor

Satoshi Tsuneda*, Tatsuo Nagano, Tatsuhiko Hoshino, Yoshihiro Ejiri, Naohiro Noda, Akira Hirata

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

184 Citations (Scopus)


Since nitrification is the rate-determining step in the biological nitrogen removal from wastewater, many research studies have been conducted on the immobilization of nitrifying bacteria. In this research, granulation of nitrifying bacteria in an aerobic upflow fluidized bed (AUFB) reactor in a nitrification process for inorganic wastewater containing 500g/m3 of NH4+-N was investigated. It was observed that spherical, pseudocubic and elliptical granules with a diameter of 346μm were produced at the bottom of the reactor after 300 days. Denaturing gradient gel electrophoresis analysis revealed that Nitrosomonas-like bacteria were the dominant ammonia-oxidizing species in the granules. Many colonies of Nitrosomonas-like bacteria were found in the outer part of the granules based on the spatial distribution analysis by fluorescence in situ hybridization. By stepwise reduction of the hydraulic retention time, the ammonia removal rate of the AUFB reactor containing these nitrifying granules finally reached 1.5kg-N/m3/day. Results suggested that the use of granules realizes the retention of a large amount of nitrifying bacteria in the reactor, which guarantees a highly efficient nitrification.

Original languageEnglish
Pages (from-to)4965-4973
Number of pages9
JournalWater Research
Issue number20
Publication statusPublished - 2003 Dec


  • Aerobic upflow fluidized bed (AUFB)
  • Ammonia-rich inorganic wastewater
  • Denaturing gradient gel electrophoresis (DGGE)
  • Fluorescence in situ hybridization (FISH)
  • Granulation
  • Nitrification

ASJC Scopus subject areas

  • Ecological Modelling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution


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