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

Su, Q., Domingo-Felez, C. , Zhang, Z., Blum, J.-M., Mark Jensen, M. and Smets, B. F. (2019) The effect of pH on N2O production in intermittently-fed nitritation reactors. Water Research, 156, pp. 223-231. (doi: 10.1016/j.watres.2019.03.015) (PMID:30921538)

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Abstract

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 (ΔN2O/ΔNH4+) 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.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Domingo-Felez, Dr Carlos
Authors: Su, Q., Domingo-Felez, C., Zhang, Z., Blum, J.-M., Mark Jensen, M., and Smets, B. F.
College/School:College of Science and Engineering > School of Engineering > Infrastructure and Environment
Journal Name:Water Research
Publisher:Elsevier
ISSN:0043-1354
ISSN (Online):1879-2448
Published Online:15 March 2019

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