The effect of pH on N2O production in intermittently-fed nitritation reactors

WATER RESEARCH

卷:156

Article

Su, Qingxian¹  Domingo-Felez, Carlos¹  Zhang, Zhen¹  Blum, Jan-Michael¹  Jensen, Marlene Mark¹  Smets, Barth F.¹ 

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

关键词: Nitrous oxide;    pH effect;    Ammonia oxidizing bacteria;    Nitritation;    Nitrifier denitrification;   

DOI  :  10.1016/j.watres.2019.03.015

来源: Elsevier

【 摘 要 】

The effect of pH on nitrous oxide (N2O) production rates was quantified in an intermittently-fed lab-scale sequencing batch reactor performing high-rate nitritation. N2O and other nitrogen (N) species (e.g. ammonium (NH4+), nitrite, hydroxylamine and nitric oxide) were monitored to identify in-cycle dynamics and determine N conversion rates at controlled pH set-points (6.5, 7, 7.5, 8 and 8.5). Operational conditions and microbial compositions remained similar during long-term reactor-scale pH campaigns. The specific ammonium removal rates and nitrite accumulation rates varied little with varying pH levels (p > 0.05). The specific net N2O production rates and net N2O yield of NH4+ removed (Delta N2O/Delta NH4+) increased up to seven-fold from pH 6.5 to 8, and decreased slightly with further pH increase to 8.5 (p < 0.05). Best-fit model simulations predicted nitrifier denitrification as the dominant N2O production pathway (>= 87% of total net N2O production) at all examined pH. Our study highlights the effect of pH on biologically mediated N2O emissions in nitrogen removal systems and its importance in the design of N2O mitigation strategies. (C) 2019 Elsevier Ltd. All rights reserved.

【 授权许可】

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