Effect of pH on N2O reduction and accumulation during denitrification by methanol utilizing denitrifiers

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

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Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)4832-4840
Journal / PublicationWater Research
Volume46
Issue number15
Publication statusPublished - 1 Oct 2012
Externally publishedYes

Abstract

Acidic pH has previously been found to increase nitrous oxide (N2O) accumulation during heterotrophic denitrification in biological wastewater treatment. However, the mechanism of this phenomenon still needs to be clarified. By using an enriched methanol utilizing denitrifying culture as an example, this paper presents a comprehensive study on the effect of pH (6.0-9.0) on N2O reduction kinetics with N2O as the sole electron acceptor, as well as the effect of pH on N2O accumulation with N2O as an intermediate of nitrate reduction. The pH dependency of nitrate and nitrite reduction was also investigated. The maximum biomass-specific N2O reduction rate is higher than the corresponding maximum nitrate and nitrite reduction rates in the entire pH range studied. However, the maximum biomass-specific N2O reduction rate is much more sensitive to pH variation outside of the optimal range (pH 7.5 to pH 8.0) than the maximum biomass-specific nitrate and nitrite reduction rates. The half-saturation coefficient of the N2O reductase increased from 0.10 mg N2O-N/L to 0.92 mg N2O-N/L as pH increased from pH 6.0 to 9.0. At pH 6.0, approximately 20% and 40% of the denitrified nitrate accumulated as N2O in the presence and absence of methanol (as an exogenous carbon source), respectively. However, at pH 6.5, these fractions decreased to 0% and 30%, respectively. No N2O accumulation occurred at pH 7.0 to 9.0 independent of the availability of methanol. These results suggest that the competition for electrons among different nitrogen oxides reductases likely plays a role in N2O accumulation at low pH conditions. © 2012 Elsevier Ltd.

Research Area(s)

  • Denitrification, Methanol, Model, Nitrous oxide, PH

Bibliographic Note

Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to lbscholars@cityu.edu.hk.

Citation Format(s)

Effect of pH on N2O reduction and accumulation during denitrification by methanol utilizing denitrifiers. / Pan, Yuting; Ye, Liu; Ni, Bing-Jie et al.
In: Water Research, Vol. 46, No. 15, 01.10.2012, p. 4832-4840.

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