Community survey of ammonia-oxidizing bacteria in full-scale activated sludge processes with different solids retention time
2005 (English)In: Journal of Applied Microbiology, ISSN 1364-5072, Vol. 99, no 3, 629-640 p.Article in journal (Refereed) Published
Aims: To study the effects of different solids retention time (SRT) on the nitrification activity and community composition of ammonia-oxidizing bacteria (AOB) in two full-scale activated sludge processes during a 5-month period. Methods and Results: The AOB community composition was analysed using fluorescence in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE), and the identified populations were enumerated by quantitative FISH. Potential nitrification rates were determined in batch tests and the in situ rates were calculated from mass balances of nitrogen in the plants. Increased SRT reduced the nitrification activity, but neither the number per mixed liquor suspended solids nor community composition of AOB were affected. Two dominant AOB populations related to Nitrosomonas europaea and Nitrosomonas oligotropha were identified by FISH, whereas only the latter could be detected by DGGE. Conclusions: The effect of a longer SRT on the activity was probably because of physiological changes in the AOB community rather than a change in community composition. Significance and Impact of the Study: Physiological alterations of a stable AOB community are possible and may stabilize activated sludge processes. The commonly used FISH probes designed to target all beta-proteobacterial AOB does not detect certain Nitrosomonas oligotropha populations, leading to an underestimation of AOB if a wider set of probes is not used. © 2005 The Society for Applied Microbiology.
Place, publisher, year, edition, pages
2005. Vol. 99, no 3, 629-640 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-31223DOI: 10.1111/j.1365-2672.2005.02608.xLocal ID: 16973OAI: oai:DiVA.org:liu-31223DiVA: diva2:252046