The effect of pH on N2O production under aerobic conditions in a partial nitritation system

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Detail(s)

Original languageEnglish
Pages (from-to)5934-5944
Journal / PublicationWater Research
Volume45
Issue number18
Publication statusPublished - 15 Nov 2011
Externally publishedYes

Abstract

Ammonia-oxidising bacteria (AOB) are a major contributor to nitrous oxide (N2O) emissions during nitrogen transformation. N2O production was observed under both anoxic and aerobic conditions in a lab-scale partial nitritation system operated as a sequencing batch reactor (SBR). The system achieved 55±5% conversion of the 1g NH4+-N/L contained in a synthetic anaerobic digester liquor to nitrite. The N2O emission factor was 1.0±0.1% of the ammonium converted. pH was shown to have a major impact on the N2O production rate of the AOB enriched culture. In the investigated pH range of 6.0-8.5, the specific N2O production was the lowest between pH 6.0 and 7.0 at a rate of 0.15±0.01mgN2O-N/h/g VSS, but increased with pH to a maximum of 0.53±0.04mgN2O-N/h/g VSS at pH 8.0. The same trend was also observed for the specific ammonium oxidation rate (AOR) with the maximum AOR reached at pH 8.0. A linear relationship between the N2O production rate and AOR was observed suggesting that increased ammonium oxidation activity may have promoted N2O production. The N2O production rate was constant across free ammonia (FA) and free nitrous acid (FNA) concentrations of 5-78mg NH3-N/L and 0.15-4.6mg HNO2-N/L, respectively, indicating that the observed pH effect was not due to changes in FA or FNA concentrations. © 2011 Elsevier Ltd.

Research Area(s)

  • Ammonia-oxidising bacteria, Anaerobic digester liquor, Greenhouse gas emissions, Nitrous oxide, Partial nitritation, PH, Sequencing batch reactor, Wastewater treatment

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Citation Format(s)

The effect of pH on N2O production under aerobic conditions in a partial nitritation system. / Law, Yingyu; Lant, Paul; Yuan, Zhiguo.
In: Water Research, Vol. 45, No. 18, 15.11.2011, p. 5934-5944.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review