Treatment of sewage by a UASB reactor under moderate to low temperature conditions

Shigeki Uemura, Hideki Harada

Research output: Contribution to journalArticlepeer-review

126 Citations (Scopus)


The feasibility of sewage treatment by an upflow anaerobic sludge blanket (UASB) reactor was studied using actual sewage at a fixed hydraulic retention time (HRT) of 4.7 h, and at temperatures in the range of 25-13°C, for six months. The average total COD removals and solid COD removals achieved were 70% and 80%, respectively. Total COD removal rate depended on influent strength, especially solid COD concentration, rather than operational temperature. Particulate organic matter in the influent was effectively removed by entrapment in the sludge bed. The hydrolysis rate of the entrapped organics was significantly affected by temperature, that is, 58% of the entrapped particulate organics was liquefied at 25°C, decreasing to 33% at 13°C. The methanogenic activity of the retained sludge decreased eventually to 4-10% of the seed granular sludge which had been formed on carbohydrate wastewater. Microscopic observation of the morphology of the sludge revealed that even though the sludge remained in granular form as a whole, the granules tended to be partly broken in a state of autolysis. Copyright (C) 1999 Elsevier Science Ltd.

Original languageEnglish
Pages (from-to)275-282
Number of pages8
JournalBioresource Technology
Issue number3
Publication statusPublished - 2000 May


  • Anaerobic sewage treatment
  • Liquefaction
  • Methane fermentation
  • Methanogenic activity
  • UASB reactor

ASJC Scopus subject areas

  • Bioengineering
  • Environmental Engineering
  • Renewable Energy, Sustainability and the Environment
  • Waste Management and Disposal


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