A2O工艺中N2O的产生与逸散特征

目前污水处理过程中产生温室气体的问题已经引起普遍关注。本文通过实验室小试，研究了不同污水水质条件下A2O工艺中N2O的产生特征，以及氧化亚氮还原酶编码基因nosZ含量对N2O产生量的影响。结果表明，在A2O工艺中的各单元均有N2O产生，其中厌氧池产生量最大，约占总产生量的32％～85％；A2O工艺产生的N2O主要通过逸散进入大气，少量随二沉池出水进入到环境中。N2O的产生量与污泥中nosZ的含量成负相关，而碳源和DO对含有nosZ基因的反硝化细菌有明显的影响，低DO环境和充足的碳源能够极大的促进其含量的提高，从而显著减少N2O的产生量。

Characteristics of N2O generation and emission in A2O process

The generation of greenhouse gases in wastewater treatment processes has caused widespread concern. In this study, the characteristics of N2O generation and the influence of nosZ gene content were investi- gated under different wastewater quality in a lab-scale A2O process. The experimental results showed that N2O was generated in each unit of the treatment process and anaerobic tank produced the most N2O （32% -85% of the total N2O）. The main emission pathway of N2Owas releasing to atmosphere with little taking away with efflu- ent. Moreover, negative correlation was showed between N2O generation and nosZ gene contents. Both carbon source and dissolved oxygen （DO） would significantly affect the denitrifying bacteria with nosZ gene. Low DO concentration and sufficient carbon source would promote their growth and lead to the significant reduction of N2O generation.