完全自养脱氮（CANON）工艺具有节能减耗、工艺流程简捷等优势，但过程中强温室气体N2O的有效减排一直是阻碍其工程应用的瓶颈，更有效的工艺控制和更全面的N2O代谢机理解析是攻克此难题的关键。申请人前期发现外加微量N2H4提高CANON工艺脱氮效率同时显著抑制N2O产生。为揭示该过程的关键酶及相关菌群代谢机制，拟开展以下研究：构建CANON工艺系统，通过调控外加N2H4浓度，得到高脱氮率、低N2O排放的优化工艺；采用高通量测序手段，经热图分析等解析外加N2H4前后系统中菌群结构变化与功能多样性，结合宏基因组测序分析，经KEGG代谢通路注释等揭示基因多样性，辨识抑制N2O产生的未知酶系；基于以上结果，利用宏转录组学手段，经基因表达谱分析等明晰抑制N2O产生的关键酶及与之相关菌群的代谢机制。研究成果将完善CANON过程的N2O生成机制，为实现高效脱氮和N2O减排协同的CANON工艺提供理论支撑。

Completely autotrophic ammonium removal over nitrite (CANON) process has the advantages of energy conservation and consumption reduction and with the simple process. But the effective controlling of N2O production, which is the strong green house gas, restricts the engineering application. A more effective process control and a more comprehensive analysis for N2O metabolism are key ways to resolve this difficult problem.It is noted that trace N2H4 addition promoted the nitrogen removal efficiency and inhibited N2O production simultaneously. In order to expound metabolism of key enzymes and related bacteria, the following research are intended to carry out:firstly, building CANON process system, by controlling concentrations of N2H4 added to optimize the process with high-efficiency nitrogen removal and low N2O emission; secondly, under high-throughput sequencing method, Heatmap analysis is used for the change of structure and function diversity of flora before and after N2H4 addition in the system, and combined with metagenome sequencing analysis, through KEGG metabolic pathway annotation and technical means are to reveal genetic diversity and identify unknown enzymes which inhibit N2O production in the system before and after N2H4 addition; and finally, based on above results, further study by metatranscriptome sequencing analysis through gene expression profile analysis and technical means are to clear key enzymes that inhibit N2O production and the related metabolic mechanism. The research results will complement the mechanism of N2O formation of CANON process, and provide theoretical support for the realization of the synergetic CANON process with high-efficiency nitrogen removal and low N2O emission.