中文摘要：

N2O是3种主要的温室气体之一，污水的生物脱氮过程是N2O产生的一个主要人为来源。通过对不同条件下生活污水短程硝化过程中N2O的产生情况进行研究，考察了短程硝化过程中硝化速率（AOR）与N2O产生速率（N2OR）之间的关系。结果表明：随着DO水平的提高，AOR逐渐上升，N2OR则呈现先增加后减少的趋势；最大N2OR出现在DO为0.6 mg·L-1时，为1.29 mg N2O-N·（g MLVSS）-1·h-1。低DO水平下AOR的提高会引起N2OR的增加；但高DO水平下较高的AOR不一定产生较多的N2O。不同条件下，N2O的产生途径不同，引起N2OR的变化。在DO较低时，N2O的产生以NH2OH/NOH途径为主，AOR的提高会促进N2O产生；随着DO的增加，N2O的产生途径主要为AOB的有氧反硝化作用，此时较高的DO水平会对这一反应造成抑制，虽然反应过程中AOR较高，但N2OR处于较低水平。

英文摘要：

Nitrous oxide （N2O） is one of the three main greenhouse gases （CO2, CH4, N2O）, about 265 times more effective than carbon dioxide （CO2）, and it may also destruct the ozone layer. In wastewater biological nitrogen removal process, autotrophic nitrification has been thought to be the major source of N2O production. In this study, by testing the production of N2Ounder different conditions, the relationship between N2Oproduction rate and ammonia oxidation rate during nitritation process was investigated in a laboratory batch-scale system with activated sludge for treating domestic wastewater. The experimental data indicated that the ammonia oxidation rate （AOR） increased with higher DO while N2O production rate （N2OR） increased first then decreased. Besides the AOR and N2OR were by varying the initial ammonium （＋4NH-N） concentration in batch experiments. The max N2OR was 1.29 mg N2O·（g MLVSS）-1·h-1 when DO was 0.6 mg·L-1. At low DO level, the increase of AOR would promote the N2OR. On the other hand, higher AOR might not produce more N2O when DO was high. There were different pathways of N2O production under various conditions which led to the change of N2OR.＆nbsp;When DO was low, N2O was mainly produced by nitrosyl radical （NOH）, while increasing AOR promoted the N2OR formation. However, nitrifier denitrification by AOB was the main way of producing N2O at high DO level. This pathway might be inhibited by high DO, and thus even there was high AOR, the net production of N2O was still less. In addition, the existence of＋4NH was very important to N2O production too.