盐度对垃圾渗滤液短程脱氮性能及其N_2O产量的影响

Impact of salinity Shock on nitrogen removal and N_2O output in treating landfill leachate

采用两级UASB-A/O工艺处理垃圾渗滤液,以A/O反应器内具有良好短程生物脱氮特性的污泥进行批次试验,围绕活性污泥短程脱氮,考察了NaCl盐度冲击对不同菌群比好氧呼吸速率(SOUR)、氨氧化速率、亚硝积累率以及pH变化规律的影响,并重点研究了盐度冲击对亚硝酸型反硝化过程中N2O产量的影响。结果表明:当盐度升高时,盐度对各菌群的抑制强度依次为亚硝酸盐氧化菌(NOB)>氨氧化菌(AOB)>碳氧化菌,而在应对盐度突降方面,碳氧化菌和NOB对盐度的适应性稍强于AOB;各盐度下的氨氧化速率整体表现为随着盐度的增高而逐渐降低,但氨氧化速率的降低幅度有较大的差异;在初始游离氨相同的前提下,亚硝积累率随着盐度的不断增加呈现小幅上升,从5g.L-1盐度下的93.1%上升到35g.L-1盐度下的98.6%;pH曲线可以作为实时控制的关键参数用以指示盐度冲击下短程硝化反硝化的结束;盐度的突变会使得亚硝酸型反硝化过程中N2O峰值出现时间延后并且浓度增加。

Landfill leachate is treated by two-stage UASB-A/O process.Batch tests were conducted with the activated sludge taken from A/O reactor,which is of good properties of biological nitrogen removal.The impacts of salinity shocks on SOUR,ammonia oxidation rate,and nitrite accumulation rate of different microorganisms,as well as profile of pH,are investigated,especially,its effect on N2O production during nitrite denitrification.The results show that the order of inhibition strength by salinity is follows：NOB〉AOB〉carbon oxidation bacteria;while the reaction for salinity shocks：carbon-oxidizing bacteria and NOB are better than AOB.For all microorganisms tested,the ammonia oxidation rate decrease gradually with increase of salinity,but the reduction level is quite different.At the same concentration of initial ammonia,nitrite accumulation rate goes slightly up with the increase of salinity,from 93.1% at 5 g·L-1 salt to 98.6% at 35 g·L-1 salt.The curve of pH can be used as on-line control parameters,indicating the end of short-nitrification and short-denitrification by salinity shock.The delay of nitrite denitrification and the increase of N2O peak concentration would appear during the process of salinity shock.