Jing Zhou, Pengying Xiao, Baowen Kang, Gang Yuan, Lei Guo, and Tiantao Zhao. Enhanced Nitritation through Long-Term Hydroxylamine Addition: Insight into Ammonium Oxidation Activity and Microbial Community. Dynamic Systems and Applications 29 (2020) No. 9, 2889 – 2904
https://doi.org/10.46719/dsa202029910
ABSTRACT.
For the purpose of approach to the un-stability nitritation caused by the low ammonium oxidation activity and possible competition of nitrite oxidation bacteria (NOB) overgrowth, a laboratory-scale SBR has been running to study the effects of hydroxylamine (NH2OH) dose concentrations through long-term addition on nitritation and characteristics of microbial communities in this process. The results showed that the ammonium-nitrogen (NH4+-N) removal and nitrite-nitrogen (NO2–N) accumulation efficiencies were rose by 113.5% and 42.8%, respectively, owing to the long-term addition of NH2OH in nitritation. The specific ammonium oxidation rate (SAOR) was calculated by a linear fit method, which was boosted by 2.5 times than before through long-term NH2OH addition. Moreover, the ratio of effluent nitrite to ammonium was in the range of 1.19~1.42, which was a suitable influent concentration of the anaerobic ammonia oxidation (ANAMMOX) process. Long-term NH2OH addition enhanced the activity of aerobic ammonium oxidation to achieve a stable nitritation. High-throughput sequencing analysis indicated that heterotrophic and autotrophic nitrogen removal bacteria were coexisted, including dominant bacteria with heterotrophic oxidation and aerobic denitrification (HN-AD) bacteria consisting of unclassified Comamonadaceae and Comamonas, and ammonia oxidizing bacteria (AOB) classified as Nitrosomonas genera. The HN-AD bacteria abundances soared but NOB abundances dropped through NH2OH addition signifying promotion of ammonium oxidation activity but restriction of the nitrite oxidation activity, to be benefit for nitrite accumulation. In addition, the relative abundance of AOB was almost invariant after NH2OH addition, safeguarding nitrification under a high efficiency and stability conditions.
Keywords: Hydroxylamine; Ammonium oxidation; Heterotrophic oxidation and aerobic denitrification; Microbial community.