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Nitrogen-associated niche characteristics and bacterial community estimated by 15N-DNA-stable isotope probing in one-stage partial nitritation/anammox process with different ammonium loading

Li, Ning, Zeng, Wei, Guo, Yu, Li, Chao, Ma, Chenyang, Peng, Yongzhen
Journal of environmental management 2019 v.247 pp. 603-612
Nitrobacter, ammonium, ammonium nitrogen, anaerobic ammonium oxidation, bacterial communities, dissolved oxygen, genes, isotope labeling, long term effects, niches, nitrifying bacteria, nitrogen, pollution load, sewage treatment, surveys, symbiosis, total nitrogen, wastewater
Anaerobic ammonium oxidation coupled with partial nitritation is critical for cleaner production in sewage treatment. The long-term effects of high- and low-strength influent ammonium (NH4+-N) on the anammox activity, ecological niche characteristics and active microbial community were investigated in a one-stage partial nitritation/anammox (PN/A) process. The total nitrogen (TN) removal efficiency was up to 90% with influent NH4+-N of 192 mg/L. The 15N-isotope pairing technique illustrated that the potential anammox rate could reach to 3507.8 nmoL/g-sludge/h, accounting for 73.2% of dinitrogen production. As the influent NH4+-N decreased to 63 mg/L, the anammox population significantly decreased and the Nitrospira became the dominant specialized species in the PN/A system. The Nitrobacter had the smallest niche overlap value and the furthest ecological distance to the anammox bacteria among the seven investigated nitrogen conversion-related genes along the influent NH4+-N concentration gradient, indicating different ecological similarities. The redundancy analysis showed that the rise of dissolved oxygen caused by low NH4+-N might be the main cause of the excessive proliferation of the Nitrospira. The 15N-DNA-stable isotope probing illustrated that both the class Anaerolineae and Proteobacteria had closely symbiotic relations with the Planctomycetacia in this in situ surveys. This study provides a deep understanding of PN/A process treating low-ammonium mainstream wastewater from the viewpoint of microecology.