Low nitrous oxide production through nitrifier-denitrification in intermittent-feed high-rate nitritation reactors

WATER RESEARCH

卷:123

Article

Su, Qingxian¹  Ma, Chun^2,3  Domingo-Felez, Carlos¹  Kfil, Anne Sofie¹  Thamdrup, Bo^2,3  Jensen, Marlene Mark¹  Smets, Barth F.¹ 

[1] Tech Univ Denmark, Dept Environm Engn, DK-2800 Lyngby, Denmark

[2] Univ Southern Denmark, Nord Ctr Earth Evolut, DK-5230 Odense M, Denmark

[3] Univ Southern Denmark, Inst Biol, DK-5230 Odense M, Denmark

关键词: Nitrous oxide;    Nitritation;    Ammonia-oxidizing bacteria;    Intermittent feeding;    pH;    Nitrifier denitrification;   

DOI  :  10.1016/j.watres.2017.06.067

来源: Elsevier

【 摘 要 】

Nitrous oxide (N2O) production from autotrophic nitrogen conversion processes, especially nitritation systems, can be significant, requires understanding and calls for mitigation. In this study, the rates and pathways of N2O production were quantified in two lab-scale sequencing batch reactors operated with intermittent feeding and demonstrating long-term and high-rate nitritation. The resulting reactor biomass was highly enriched in ammonia-oxidizing bacteria, and converted similar to 93 +/- 14% of the oxidized ammonium to nitrite. The low DO set-point combined with intermittent feeding was sufficient to maintain high nitritation efficiency and high nitritation rates at 20-26 degrees C over a period of similar to 300 days. Even at the high nitritation efficiencies, net N2O production was low (similar to 2% of the oxidized ammonium). Net N2O production rates transiently increased with a rise in pH after each feeding, suggesting a potential effect of pH on N2O production. In situ application of N-15 labeled substrates revealed nitrifier denitrification as the dominant pathway of N2O production. Our study highlights operational conditions that minimize N2O emission from two-stage autotrophic nitrogen removal systems. (C) 2017 Elsevier Ltd. All rights reserved.

【 授权许可】

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