Abstract
In this study, a lab scale EGSB reactor was operated for 400 days to investigate the influence of temperature-decrease on the microbial characteristic of retained sludge. The EGSB reactor was started-up at 15°C seeding with 20°C-grown granular sludge. The influent COD of synthetic wastewater was set at 0.6-0.8 gCOD/L. The process-temperature was stepwise reduced from 15°C to 5°C during 400 days operation. Decrease of temperature of the reactor from 15°C to 10°C caused the decline of COD removal efficiency. However, continuous operation of the EGSB reactor led the efficient treatment of wastewater (70% of COD removal, 50% of methane recovery) at 10°C. We confirmed that the both acetate-fed and hydrogen-fed methanogenic activities of retained sludge clearly increased under 15 to 20°C. Changes of microbial profiles of methanogenic bacteria were analyzed by 16S rDNA-targeted DGGE analysis and cloning. It shows that genus Methanospirillum as hydrogen-utilizing methanogen proliferated due to low temperature operation of the reactor. On the other hand, genus Methanosaeta presented in abundance as acetoclastic-methanogen throughout the experiment.
Original language | English |
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Pages (from-to) | 277-281 |
Number of pages | 5 |
Journal | Water Science and Technology |
Volume | 57 |
Issue number | 2 |
DOIs | |
Publication status | Published - 2008 Mar 10 |
Keywords
- EGSB
- Low strength wastewater
- Low temperature
- Methane fermentation
- Methanospirillum
- Microbial structure
ASJC Scopus subject areas
- Environmental Engineering
- Water Science and Technology