低DO硝化耦合内碳源反硝化脱氮处理生活污水

为了进一步合理利用碳源，降低曝气能耗，有效解决低C/N生活污水的脱氮问题，采用2个串联的SBR在无外加碳源的条件下处理低C/N实际生活污水，分别启动内碳源反硝化反应器（ED-SBR）和低DO硝化反应器（LDON-SBR），并按照厌氧（ED-SBR）-好氧（LDON-SBR）-缺氧（ED-SBR）的方式运行，综合考察各反应器处理性能，并探讨低DO硝化耦合内碳源反硝化工艺脱氮的可行性.结果表明：LDON-SBR反应器在DO浓度为0.3~0.5mg/L的条件下能够成功实现90%以上的硝化并稳定维持，同时反应器存在明显的同步硝化反硝化（SND）现象，SND率可达29.6%；ED-SBR反应器在厌氧阶段能够将进水中的有机物转化为内碳源并储存，在缺氧阶段能够进行内源反硝化，使NO₃^--N平均浓度从27.3mg/L降低至3.9mg/L，NO₃^--N平均去除率为86.5%；系统整体COD去除率为80%左右.

Treatment of domestic wastewater by low DO nitrification coupled with endogenous denitrification system

To further utilize carbon source and reduce aeration energy consumption, endogenous denitrification reactor (ED-SBR) coupled with the low DO nitrification reactor (LDON-SBR) were used to treat low C/N domestic wastewater without additional carbon sources. The operation mode was: anaerobic (ED-SBR)-aerobic (LDON-SBR)-anoxic (ED-SBR). The feasibility of endogenous denitrification coupled with the low DO nitrification was evaluated according to the performance of ED-SBR/ LDON-SBR system. The results showed that low DO concentration (0.3~0.5mg/L) maintained a stable nitrification performance in the LDON-SBR, and the nitrifying efficiency reached up to 90%. Meanwhile low DO concentration enhanced simultaneous nitrification and denitrification (SND), and the average SND rate was 29.6% in the LDON-SBR; In the ED-SBR, the organic matter of influent was stored as internal carbon source in the anaerobic period. The stored internal carbon source could be used for endogenous denitrification in the next anoxic period, which reduced NO₃^--N concentration from 27.3mg/L to 3.9mg/L in the ED-SBR with a NO₃^--N removal rate of 86.5%; In addition, the COD removal rate was about 80% in the low DO nitrification coupled with endogenous denitrification system.