城市污水自养脱氮复合微生物系统中氮素转化与N2O产生机理

Ammonia oxidization is the most important process of achieving sustainable nitrogen removal form municipal wastewater. Until now, N2O producing pathway and enzyme catalytic mechanism are still unclear. Reducing and control of N2O during ammonia oxidization autotrophic nitrogen removal from municipal wastewater need to be developed and improved. In this project, based on the variation of microbial communities, key nitrogen compounds during aerobic ammonia oxidization and anaerobic ammonia oxidization for treating municipal wastewater under different operational and environmental conditions, producing mechanisms, key influencing factors and threshold value of N2O emission during aerobic ammonia oxidization and anaerobic ammonia oxidization is identified. After determination of operational parameters for stable operation and key factors of N2O production, parameters for reducing and control of N2O production is identifyed. Based on the above study, two stage ammonia oxidization autotrophic nitrogen removal from municipal wastewater process is established. Moreover, key combination control technologies of keeping stable operation and preventing N2O emission from this complex biochemical reaction process are determined. This research can improve and perfect new sustainable wastewater treatment technology with high removal efficiency and low greenhouse gas emission.

氨氧化过程是未来可持续污水处理工艺的决定性环节，其过程中氮素转化和N2O产生机理的研究尚不完善，氨氧化过程自养脱氮过程中N2O防逸控制方法也有待于进一步开发与完善。本课题以实际城市污水为研究对象，针对两种典型氨氧化过程——好氧氨氧化和厌氧氨氧化过程开展理论和工艺研究，基于不同运行条件和环境条件，考察好氧氨氧化和厌氧氨氧化生化反应过程中微生物种群结构与相互作用关系、关键氮素物质的产生与变化情况，确定N2O产生机制与关键因子及其阈值。甄别工艺稳定运行调控参数与N2O产生关键因子，确定好氧氨氧化和厌氧氨氧化过程N2O防逸控制参数。在此基础上，构建城市污水两段式氨氧化自养脱氮工艺系统，确定工艺稳定运行与复合生化反应过程中N2O防逸联合调控的关键技术,不断完善高效低碳可持续的污水处理新工艺与新技术。

好氧氨氧化和厌氧氨氧化过程是可持续污水处理工艺的决定性环节，其过程中氮素转化和氧化亚氮（N2O）产生机理的研究尚需完善。本课题在实现城市污水自养脱氮工艺和高氨氮废水自养脱氮工艺的基础上，发现好氧氨氧化菌和厌氧氨氧化菌仅为关键功能菌，反硝化菌对于厌氧氨氧化生物膜系统形成具有关键作用。通过调控系统运行条件和环境条件，使厌氧氨氧化菌在与好氧氨氧化菌和亚硝酸盐氧化菌的竞争中占有优势，是实现自养脱氮工艺稳定和保证总氮去除的关键。两种典型工艺在不同运行条件和环境条件下，氮素主要通过厌氧氨氧化、异养反硝化和氨氧化过程中N2O的产生三种途径去除。溶解氧（DO）浓度、回流比和生物滤池的反冲洗是微生物种群和N2O产生的关键调控因子。通过确定关键调控因子的阈值，进一步优化了所构建的城市污水和高氨氮废水自养脱氮工艺,以不断完善高效低碳可持续的污水处理新工艺与新技术。