Isotopic analysis of N2O produced in a conventional wastewater treatment system operated under different aeration conditions

Tumendelger, Azzaya; Toyoda, Sakae; Yoshida, Naohiro

doi:10.1002/rcm.6973

Cited by 36 publications

(14 citation statements)

References 42 publications

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“…Based on this mapping approach, most of data was fallen near to NO 2 -reduction suggesting that the nitrifierdenitrification was dominant pathway to N 2 O production. This is agreed with previous results that found nitrifierdenitrification was a key process for N 2 O production in aerobic tank of CAS system applied in Japanese WWTP [11,12]. The contribution of this pathway is estimated as 87-99% at stations N1-1, N1-4 and N5-4, respectively.…”

Section: Concentrations Of Dissolved Inorganic Nitrogen (Din) Compounsupporting

confidence: 92%

“…Using this technique, Sutka et al [8][9][10] found that the SP for N 2 O from hydroxylamine oxidation (~33‰) and nitrite reduction (~0‰) differs in a pure culture study and noted that this difference can be used to distinguish the relative contributions of nitrification and denitrification sources to N 2 O emissions. There have still been only several reported studies which applied this measurement technique to field N 2 O samples [11,12] or referred to the relative contributions of nitrification and denitrification. To our knowledge, the present study is the first to (1) apply the stable isotopic analysis to the determination of N 2 O sources during the case of WWTS in Mongolia and to (2) understand the actual contributions of nitrification and denitrification to N 2 O production.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of dissolved N2O production processes during wastewater treatment system in Ulaanbaatar

et al. 2017

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Nitrous oxide (N 2 O) is an increasing greenhouse gas in the troposphere and a potential destroyer of stratospheric ozone layer. Wastewater treatment plant (WWTP) is one of the anthropogenic N 2 O sources because inorganic and organic nitrogen compounds are converted to nitrate (NO 3 -, in the case of standard system) or N 2 (in the case of advanced system) by bacterial nitrification and denitrifcation processes in WWTP. These major processes can be distinguished by isotopocule analysis. In order to reveal production mechanisms of N 2 O in a standard wastewater treatment, we made water sampling at the central WWTP in Ulaanbaatar. The water samples collected from seven stations including biological reaction tanks were measured for concentration and isotopocule ratios of dissolved N 2 O and other inorganic nitrogen. Dissolved N 2 O concentration was extremely higher than that expected under atmospheric equilibrium (about 9 nmol/l) at all stations, indicating that this system is a potential source of N 2 O. It showed a gradual increase with the progress of biological reaction and the highest concentration (335.7 nmol/l) was observed at station N5-4 of the aeration tank when the DO was 5.7 mg/l. Nitrification by nitrifying bacteria could actively occur by the concentration of NH 4 + decreased whereas NO 2 -and NO 3 -showed a temporal and monotonic increase, respectively, under high DO concentration. Although the reported values of site preference (SP) of N 2 O, the difference in 15 N/ 14 N ratio between central (α) and terminal (β) nitrogen, produced via NO 2 -reduction (SP(ND)), including both nitrifier and denitrifier denitrification, and NH 2 OH oxidation (SP(HO)) ranged from -10.7‰ to 0‰ and 31.4‰ to 36.3‰, respectively, the observed SP at aeration tank was close to SP(ND) rather than SP(HO). It was ranged from 0.4‰ to 13.3‰ when N 2 O concentration was high, implying that the NO 2 -reduction made a greater contribution to N 2 O production. Slightly elevated SP (13.3‰) only at station N5-1 was derived from the mixing of N 2 O produced via NH 2 OH oxidation and the maximal contribution of this pathway was estimated to be about 40%. In other words, the contribution of NO 2 -reduction was more than 60%.

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Section: Concentrations Of Dissolved Inorganic Nitrogen (Din) Compounsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Investigation of dissolved N2O production processes during wastewater treatment system in Ulaanbaatar

et al. 2017

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“…In general, N 2 O concentration is higher and δ 15 N and δ 18 O are lower in aerobic water than in anaerobic water; those features possibly reflect the process that occur under each condition: nitrification and denitrification. The SP value observed in aerobic process tanks of a WWTP indicated that N 2 O was produced by nitrifier denitrification (Yoshinari & Wahlen, 1985; Townsend‐Small et al, ; Toyoda et al, ; Wunderlin et al, ; Tumendelger, Toyoda, & Yoshida, ). Table presents the reported isotopic signature of N 2 O from human sewage treatment processes.…”

Section: N2o Isotopocules In Various Environmentsmentioning

confidence: 99%

Isotopocule analysis of biologically produced nitrous oxide in various environments

Toyoda

Yoshida

Koba

2015

Mass Spectrometry Reviews

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166

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Natural abundance ratios of isotopocules, molecules that have the same chemical constitution and configuration, but that only differ in isotope substitution, retain a record of a compound's origin and reactions. A method to measure isotopocule ratios of nitrous oxide (N O) has been established by using mass analysis of molecular ions and fragment ions. The method has been applied widely to environmental samples from the atmosphere, ocean, fresh water, soils, and laboratory-simulation experiments. Results show that isotopocule ratios, particularly the N-site preference (difference between isotopocule ratios N N O/ N N O and N N O/ N N O), have a wide range that depends on their production and consumption processes. Observational and laboratory studies of N O related to biological processes are reviewed and discussed to elucidate complex material cycles of this trace gas, which causes global warming and stratospheric ozone depletion. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 36:135-160, 2017.

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“…The water quality, energy consumption, cost, and N 2 O production in MLE processes for nitrogen removal depend on two operational parameters; the aeration rate in the aerobic tank and the internal recycle flow (IRF) rate from the aerobic to the anoxic tank (Jimenez et al 2011;Tumendelger et al 2014). The aeration rate in the aerobic tank determines the gas-liquid equilibrium between the dissolved and gaseous N 2 O.…”

Section: Introductionmentioning

confidence: 99%

Effects of aeration and internal recycle flow on nitrous oxide emissions from a modified Ludzak–Ettinger process fed with glycerol

Song

Suenaga

Harper

et al. 2015

Environ Sci Pollut Res

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Nitrous oxide (N2O) is emitted from a modified Ludzak-Ettinger (MLE) process, as a primary activated sludge system, which requires mitigation. The effects of aeration rates and internal recycle flow (IRF) ratios on N2O emission were investigated in an MLE process fed with glycerol. Reducing the aeration rate from 1.5 to 0.5 L/min increased gaseous the N2O concentration from the aerobic tank and the dissolved N2O concentration in the anoxic tank by 54.4 and 53.4 %, respectively. During the period of higher aeration, the N2O-N conversion ratio was 0.9 % and the potential N2O reducers were predominantly Rhodobacter, which accounted for 21.8 % of the total population. Increasing the IRF ratio from 3.6 to 7.2 decreased the N2O emission rate from the aerobic tank and the dissolved N2O concentration in the anoxic tank by 56 and 48 %, respectively. This study suggests effective N2O mitigation strategies for MLE systems.

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Isotopic analysis of N₂O produced in a conventional wastewater treatment system operated under different aeration conditions

Cited by 36 publications

References 42 publications

Investigation of dissolved N<sub>2</sub>O production processes during wastewater treatment system in Ulaanbaatar

Investigation of dissolved N<sub>2</sub>O production processes during wastewater treatment system in Ulaanbaatar

Isotopocule analysis of biologically produced nitrous oxide in various environments

Effects of aeration and internal recycle flow on nitrous oxide emissions from a modified Ludzak–Ettinger process fed with glycerol

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