【摘要】 试验采用SBR反应器,分别考察了不同C/N条件下,以硝酸盐和亚硝酸盐为电子受体的反硝化过程中N2O产生情况.投加乙醇作为反硝化碳源,以硝酸盐为电子受体时调节C/N分别为0、1.2、2.4、3.5、5.0和20,以亚硝酸盐为电子受体时调节C/N分别为0、1.8、2.4、3.0、4.3、5.2、6.6和20.6.结果发现,以亚硝酸盐为电子受体时,最佳C/N为3.0,此时N2O产生量为0.044mg·L-1;以硝酸盐为电子受体时,最佳C/N为5.0,此时N2O产生量为0.135mg·L-1,是以亚硝酸盐为电子受体时的3倍.电子受体类型不同时,N2O产生量的变化趋势类似:在碳源严重不足时,反硝化率和N2O产生量均很低;碳源相对不足时N2O产生量增加;C/N过大时,虽然反硝化速率很快,但N2O产量也急剧增大.可见,与全程硝化反硝化工艺相比,短程硝化反硝化工艺可节省40%碳源,且控制C/N=3,其反硝化过程产生的N2O远少于全程反硝化.更多还原

【Abstract】 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·L -1 ;the optimum C/N ratio was 5.0 taking nitrate as electron acceptor and the N2O production was 0.135 mg·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.更多还原