[Effect of C/N ratio on nitrous oxide production during denitrification with different electron acceptors].
The experiment investigated the nitrous oxide production under different C/N ratios during denitrification, taking nitrate and nitrite as electron acceptor respectively. Ethanol was selected as carbon source. The C/N ratios were 0, 1.2, 2.4, 3.5, 5.0 and 20 when nitrate was taken as electron acceptor and C/N ratios 0, 1.8, 2.4, 3.0, 4.3, 5.2, 6.6, 20.6 when electron acceptor was nitrite. The results indicated that: the optimum C/N ratio was 3.0 taking nitrite as electron acceptor and the N2O production was 0.044 mg x L(-1); the optimum C/N ratio was 5.0 taking nitrate as electron acceptor and the N2O production was 0.135 mg x L(-1) which was 3 times higher than that of nitrite as electron acceptor. Though the electron acceptor changed, the trend of N2O production was similar: when carbon source was badly insufficient, the production of N2O and denitrification rate were both quite small; the N2O production increased with the increasing of the quantity of carbon source; when the carbon source was excessive, the N2O production sharply raised. Consequently, compared to complete nitrification and denitrification, short-cut nitrification and denitrification could save 40% carbon source. Moreover, controlling C/N = 3 could reduce the production of N2O in short-cut nitrification.
Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China. shanghuilai007@yahoo.com.cn
Hui-Lai
HL
Shang
Yong-Zhen
YZ
Peng
Jing-Rong
JR
Zhang
Shu-Ying
SY
Wang
D019149:Bioreactors; D002244:Carbon / Q000378:metabolism*; D004583:Electrons; D000431:Ethanol / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D009609:Nitrous Oxide / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods*
D009566:Nitrates; D009573:Nitrites; D000431:Ethanol; D002244:Carbon; D009609:Nitrous Oxide; D009584:Nitrogen