Publication: Occurrence of aerobic denitrifying bacteria in integrated fixed film activated sludge system
Issued Date
2021-12-01
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ISSN
18791298
00456535
00456535
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2-s2.0-85109534481
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Mahidol University
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SCOPUS
Bibliographic Citation
Chemosphere. Vol.285, (2021)
Suggested Citation
Tongchai Sriwiriyarat, Siriprapha Jangkorn, Jittima Charoenpanich, Sopa Chinwetkitvanich, Prayoon Fongsatitkul Occurrence of aerobic denitrifying bacteria in integrated fixed film activated sludge system. Chemosphere. Vol.285, (2021). doi:10.1016/j.chemosphere.2021.131504 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/76573
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Title
Occurrence of aerobic denitrifying bacteria in integrated fixed film activated sludge system
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Abstract
Denitrification can be enhanced in the Integrated Fixed Film Activated System (IFAS) system by integrating media into the anoxic or aerobic zone. The simultaneous nitrification and denitrification (SND) in the biofilm layers has been reported in the aerobic zone of the IFAS system. In this study, two IFAS systems with Bioweb® media installed in the anoxic or aerobic reactor were operated in parallel to evaluate both anoxic denitrification or aerobic SND in the biofilm layers enhanced by fixed film media at three different nitrite and nitrate recirculation (NR) ratios of 75%, 100%, and 125%. The results revealed that both IFAS systems achieved the same organic and nitrogen removal efficiencies without statistically significant difference. The NR ratio of 125% enhanced slightly the denitrification in the anoxic zones of both systems. The media increased the anoxic denitrification at the NR ratio of 100%. The SND in the biofilm was found insignificant in both systems. It was evident that suspended-growth microorganisms stored substrates internally in the cells under anoxic conditions due to insufficient retention time. The aerobic denitrifiers including Chryseobacterium sp., Klebsiella pneumonia, and Pseudomonas aeruginosa were abundant in both IFAS systems providing aerobic denitrification with storage products as carbon sources. In summary, the denitrification in the anoxic zone and SND in the biofilm of the aerobic zone, both were enhanced by the fixed film media, did not contribute significantly to the IFAS system for the biological nitrogen removal because of microbial storage products and aerobic denitrification of several aerobic denitrifiers.