Denitrification as an N2O sink

WATER RESEARCH

卷:151

Article

Conthe, Monica¹  Lycus, Pawel²  Arntzen, Magnus O.²  da Silva, Aline Ramos³  Frostegard, Asa²  Bakken, Lars R.²  Kleerebezem, Robbert¹  van Loosdrecht, Mark C. M.¹ 

[1] Delft Univ Technol, Dept Biotechnol, Delft, Netherlands

[2] Norwegian Univ Life Sci, Fac Chem Biotechnol & Food Sci, As, Norway

[3] Bioclear Earth, Rozenburglaan 13, NL-9727 DL Groningen, Netherlands

关键词: Nitrous oxide;    Denitrification;    Activated sludge;    Wastewater treatment;   

DOI  :  10.1016/j.watres.2018.11.087

来源: Elsevier

【 摘 要 】

The strong greenhouse gas nitrous oxide (N2O) can be emitted from wastewater treatment systems as a byproduct of ammonium oxidation and as the last intermediate in the stepwise reduction of nitrate to N-2 by denitrifying organisms. A potential strategy to reduce N2O emissions would be to enhance the activity of N2O reductase (NOS) in the denitrifying microbial community. A survey of existing literature on denitrification in wastewater treatment systems showed that the N2O reducing capacity (VmaxN2O -> N2) exceeded the capacity to produce N2O (VmaxN2O -> N2) by a factor of 2-10. This suggests that denitrification can be an effective sink for N2O, potentially scavenging a fraction of the N2O produced by ammonium oxidation or abiotic reactions. We conducted a series of incubation experiments with freshly sampled activated sludge from a wastewater treatment system in Oslo and found that the ratio alpha = VmaxN2O -> N2/V(max)NO3 -> N2O fluctuated between 2 and 5 in samples taken at intervals over a period of 5 weeks. Adding a cocktail of carbon substrates resulted in increasing rates, but had no significant effect on a. Based on these results complemented with qPCR and metaproteomic data we discuss whether the overcapacity to reduce N2O can be ascribed to gene/protein abundance ratios (nosZ/nir), or whether in cell competition between the reductases for electrons could be of greater importance. (C) 2018 The Author(s). Published by Elsevier Ltd.

【 授权许可】

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