Microbial structure and activity of UASB granules treating different wastewaters

H. H.P. Fang, H. K. Chui, Y. Y. Li

Research output: Contribution to journalConference articlepeer-review

121 Citations (Scopus)


The microsuucture of three types of UASB granules respectively treating sucrose, glutamate and brewery wastewaters in mesophilic conditions were analyzed by light, scanning electron and transmission electron microscopies, along with the specific methanogenic activity (SMA) of the granules. Results showed that the granule's microstructure was dependent on the nature of the substrate. Those degrading soluble carbohydrates exhibited a layered structure, while those degrading glutamate exhibited a rather uniform structure. Such a difference was explained based on the substrate's rates of acidogenesis and diffusion. A model of the typical layered structure was proposed. In addition, the acetoclastic Methanothrix was found as the key structural element in all the granulules, suggesting that it plays an important role in granulation. Three types of syntrophic microcolonies were found to be abundant in granules degrading soluble carbohydrates: two were juxtapositioned syntrophic microcolonies, each was composed of hydrogen-producing acetogens and hydrogen-consuming methanogens, while the third was a cluster-type of syntrophic association between two microcologies. The SMA data using individual VFA as substrate provided supporting evidence to the observations of the bacterial compositions in the granules.

Original languageEnglish
Pages (from-to)87-96
Number of pages10
JournalWater Science and Technology
Issue number12
Publication statusPublished - 1994
EventProceedings of the IAWQ 7th International Symposium on Anaerobic Digestion - Cape Town, S Afr
Duration: 1994 Jan 231994 Jan 28


  • Activity
  • Brewery
  • Glutamate
  • Granule
  • Microbial structure
  • Sucrose
  • Syntrophic microcolony
  • UASB


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