Physiological characteristics of predominant ammonia-oxidizing bacteria enriched from bioreactors with different influent supply regimes

• Published in: Biochemical engineering journal 2013-10, Vol.79, p.153-161
• Main Authors: Terada, Akihiko, Sugawara, Sho, Yamamoto, Tomoko, Zhou, Sheng, Koba, Keisuke, Hosomi, Masaaki
• Format: Article
• Language: English
• Subjects: acclimation; ammonia; Ammonia-oxidizing bacteria; ammonium compounds; bacteria; Biokinetic parameters; Biological and medical sciences; biomass; Bioreactors; Biotechnology; dissolved oxygen; fluorescence in situ hybridization; Fundamental and applied biological sciences. Psychology; Halophilic and halotolerant Nitrosomonas spp; Methods. Procedures. Technologies; nitrification; Nitritation; nitrogen dioxide; Nitrosomonas; Nitrosospira; Nitrosospira spp; nitrous oxide; salt tolerance; Various methods and equipments; wastewater
• ISSN: 1369-703X; 1873-295X
• DOI: 10.1016/j.bej.2013.07.012

•The effect of wastewater supply regime on nitritation performance was investigated.•Intermittent NH4+ supply achieved higher nitritation than the continuous one.•Different NH4+ supply enriched distinct ammonia-oxidizing bacteria (AOB).•The AOB population exhibited distinct biokinetic properties with NH4+ as a driver.•AOB selection by NH4+ control could be important for a cost-effective N removal. Two acclimatized biomasses exposed to ammonium (NH4+) concentration of 600mg NL−1, one from a completely stirred tank reactor (CSTR), the other from a sequencing batch reactor (SBR), were assayed for nitritation performance, predominant nitrifying bacterial population and nitrous oxide (N2O) production. By virtue of fluctuating and constant NH4+ concentrations respectively, the SBR and CSTR wastewater supply regimes were hypothesized to support different predominant ammonia-oxidizing bacteria (AOB) exhibiting distinct biokinetic properties. Nitritation efficiency (NO2−-N/NO2+3−-N) was higher in the SBR (89%) than the CSTR (30%) likely due to free ammonia and dissolved oxygen concentration. Quantitative fluorescence in situ hybridization (FISH) analyses revealed that fast-growing (r-strategist) AOB of halophilic and halotolerant Nitrosomonas lineage were more highly enriched in the SBR (76±4.2%) than the CSTR (38±6.0%). The CSTR predominantly enriched slow-growing (K-strategist) AOB Nitrosospira spp. (42±1.9% versus 1.4±0.8% in the SBR). Biokinetic parameter estimation consolidated the FISH result: the maximum growth rate and half-saturation coefficients for NH4+ were higher in the SBR (μmax=0.92 day, KNH4+=28.9mg NL−1) relative to the CSTR (μmax=0.42 day, KNH4+=3.47mg NL−1), suggesting that the extent of nitritation may be controlled by choice of wastewater influent operational regime, which itself determines predominant AOB. N2O production was a maximum of 25 times higher (10.2mg N-N2Oh−1 at 0.5mg O2L−1) in CSTR-enriched biomass than in SBR-enriched biomass (0.41mg N-N2Oh−1 at 0.5mg O2L−1).