Application of the ¹⁵N technique to determine the contributions of nitrification and denitrification to the flux of nitrous oxide from aerated pig slurry

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• 作者：Beline ; F. ; Martinez ; J. ; Marol ; C. ; Guiraud ; G.
• 关键词：nitrous oxide ; nitrification ; denitrification ; ¹⁵N ; pig slurry
• 刊名：Water Research
• 出版年：2001
• 出版时间：August, 2001
• 年：2001
• 卷：35
• 期：11
• 页码：2774-2778
• 全文大小：153 K

文摘

In order to elucidate and quantify nitrogen transformations occurring during aerobic treatment of pig slurry, two laboratory experiments were carried out with contrasting levels of aeration, high level (experiment 1) and low level (experiment 2) of aeration. During these experiments, after reaching steady-state conditions, a single pulse of NO₃⁻-¹⁵N tracer was added directly to the reactor. When nitrification conditions were prevailing (experiment 1), no transformation of added NO₃⁻-¹⁵N occurred (98.7 % ¹⁵N-recovery as nitrates in the liquid slurry). Moreover, the unlabelled nitrous oxide (N₂O) measured (7.4 % of the total nitrogen content of the raw slurry) strongly demonstrated that the source of N₂O emitted was nitrification. During simultaneous nitrification and denitrification conditions (experiment 2), the added NO₃⁻-¹⁵N was found in gaseous nitrogen forms (N₂O-¹⁵N:27 % ; N₂-¹⁵N:18 % ) and in the liquid (TN-¹⁵N:54 % ). From this result, it was evident that N₂O was mainly emitted by denitrification process. Using the decrease of the isotopic excess of the NO₃⁻-¹⁵N we calculated that 92 % of NO₂⁻-N was directly denitrified (as gaseous forms) without any previous oxidation to nitrate.