污水生化处理中N2O产生途径、影响因素及减排策略

Pathways, influencing factors and mitigation strategies for N2O emissions in wastewater biochemical treatment

摘要:

污水处理是重要的温室气体排放源之一,污水生化处理中氧化亚氮（N₂O）的产生及排放已经成为研究的热点。N₂O的产生机制复杂,不同工艺、不同操作条件下排放特性差异大。目前,已有大量针对污水生化处理过程中N₂O产生排放的研究,但基于N₂O产生途径的分析、评述N₂O减排策略的内容较少。系统探讨了污水生化处理过程中N₂O的主要产生途径,即NH₂OH氧化、硝化细菌反硝化、异养反硝化以及非生物途径；阐述了N₂O产生的影响因素,包括碳源、氮源、盐度等污水水质特性,溶解氧、回流比等工艺参数以及微生物种群分布等；总结了相应的减排策略,即可通过工艺条件优化、不同生化工艺耦合以及低N₂O产生水平微生物种群的富集等方法有效降低N₂O的产生排放；评述了目前研究存在的问题以及未来发展方向,模型的构建仍是研究污水生化处理过程中N₂O产生排放的有效方法,在N₂O回收的研究中具有广阔前景。

Abstract:

Wastewater treatment is a significant contributor to greenhouse gas emissions, and the generation and emission of nitrous oxide (N₂O) in wastewater biochemical treatment have become a hot research topic. The production mechanism of N₂O generation is complex, and emission characteristics vary widely depending on the processes and operating conditions. While numerous studies have investigated N₂O generation and emission in wastewater biochemical treatment, there is a lack of research on N₂O emission reduction strategies based on the analysis of N₂O generation pathways. This paper systematically discusses the primary pathways of N₂O production in wastewater biochemical treatment process, including NH₂OH oxidation, nitrifier denitrification, heterotrophic denitrification, and abiotic pathways. The factors influencing N₂O production are described, including wastewater characteristics such as carbon source, nitrogen source, salinity, process parameters such as dissolved oxygen, reflux ratio, and the distribution of microbial communities. This paper summarizes corresponding mitigation strategies, highlighting the effective reduction of N₂O production and emission through process optimization, coupling different biochemical processes, and enriching microbial communities with low N₂O production levels. Current research challenges and future development directions are assessed, emphasizing that model construction remains an effective method to study N₂O production and emission biochemical treatment of wastewater, with broad prospect in N₂O recovery research.