盐度对好氧颗粒污泥硝化过程中N2O产生量的影响

采用好氧SBR反应器,考察盐度在0、5、10 g·L-1条件下好氧颗粒污泥全程硝化过程中N2O产生量的变化情况以及对系统脱氮效果的影响.结果显示,随着污水中盐度增加,N2O产生量呈递增趋势.在3个盐度下(0、5、10 g·L-1),溶解态N2O产生量分别为1.21、8.99、24.81 mg·m-3,释放态N2O产生量分别为0.95、3.46、16.45 mg·m-3.在盐度为5 g·L-1和10g·L-1条件下,N2O释放速率分别为0 g·L-1时的3.6倍和17.4倍.在3种盐度条件下无论是溶解态N2O还是释放态N2O产生量在硝化过程的变化趋势均是先上升后下降,且溶解态N2O产生量大于释放态产量.另外当盐度浓度较低时(低于5 g·L-1),对NH+4-N去除效果影响较小,NH+4-N的去除率与盐度为0 g·L-1时基本相同,均在98%以上;但当盐度升至10 g·L-1后,NH+4-N的去除率降到了70%.因此,污水中盐度增加不仅影响NH+4-N的去除效率,而且增加N2O产生量.

Effects of Salinity on N2O Production During Nitrification Using Aerobic Granular Sludge

An aerobic SBR biological wastewater treatment system was adopted to measure the N₂O production and nitrogen removal using aerobic granular sludge nitrification process under 0,5,10 g·L^-1 salinity conditions. The results showed that the N₂O production increased with the increase of salinity concentration. At three salinity levels (0,5, 10 g·L^-1), the dissolved N₂O production was 1.21, 8.99, 24.81mg·m^-3, respectively, and the released N₂O was 0.95, 3.46, 16.45 mg·m^-3, respectively. The N₂O release rates at the 5 g·L^-1 and 10 g·L^-1 salinity levels were 3.6 and 17.4 times as high as that at the 0 g·L^-1 salinity level. Under various salinity conditions both the dissolved and releasing state N₂O production first increased and then decreased, and the dissolved N₂O production was greater than that in the releasing state. In addition, when the salinity was low (less than 5 g·L^-1), the NH₄⁺-N removal rate was less affected and almost the same with the condition of 0 g·L^-1, both over 98%. When the salinity was increased to 10 g·L^-1, the NH₄⁺-N removal rate dropped to 70%. Thus, increasing the salinity of wastewater not only affected the system nitrogen removal rate but also increased the amount of N₂O production.