一种新型A2/O工艺处理特性

为提高传统A2/O工艺在碳源不足情况下的脱氮除磷效率,发明了一种改良型的污水处理工艺,该工艺通过在好氧池中增设生物相选择器实现结构较好的颗粒污泥与松散絮体污泥的分离,在低污泥龄运行条件下获得了良好的同步脱氮除磷效果.当进水COD为900 mg/L,SRT分别为30 d和20 d时,新型和传统A2/O工艺其COD和TN去除率均可达到90%和70%以上,但TP去除率并不理想.当污泥龄为10 d时,新型工艺的COD,TN,TP去除率分别为(96.7±0.9)%、(83.2±2.0)%和(87.6±2.5)%,在提高除磷效率的同时保持了良好的脱氮效果.当进水COD为300 mg/L、SRT为10 d时,新型和传统A2/O工艺TN去除率分别为(77.6±1.1)%和(58.1±3.9)%,TP去除率分别为(85.4±1.2)%和(66.4±8.3)%,表明在进水基质浓度较低的条件下,新工艺优于传统工艺.另外,在SRT为10 d时,新型和传统A2/O好氧池中TN亏损比分别为22.8%和7.8%,表明新工艺TN去除率的提高得益于同步硝化反硝化,TP去除率的提高得益于低污泥龄.

Characteristics of a new A2/O process

A new sewage treatment process was invented to improve nitrogen and phosphorus removal efficiency of the new A2/O process in low carbon source. The biological selector was set in the aerobic tank of the new process to achieve the separation between granular sludge and flocculent sludge. And the new A2/O process had a good nitrogen and phosphorus removal efficiency with short SRT. When the influent COD was 900 mg/L and SRT was 30 d or 20 d, COD and TN removal rates of the new and traditional A2/O processes could be more than 90% and 70%, respectively, but TP removal rate was not good. When SRT was 10 d, COD, TN and TP removal rates of the new process were (96.7±0.9)%, (83.2±2.0)% and (87.6±2.5)%, respectively, the new process improved phosphorus removal efficiency while maintaining a good nitrogen removal efficiency. When the influent COD was 300 mg/L and SRT was 10 d, TN removal rates of the new and traditional A2/O processes were (77.6±1.1)% and (58.1±3.9)%, respectively, and TP removal rates were (85.4±1.2)% and (66.4±8.3)%, respectively. The results indicate that the new process is superior to the traditional process in the low carbon source. In addition, when SRT was 10 d, the TN loss ratios of the new and traditional A2/O processes in the aerobic tanks were 22.8% and 7.8%, respectively. These indicate that the improvement of TN removal efficiency of the new process can be attributed to simultaneous nitrification and denitrification (SND) and that short SRT results in improvement of TP removal efficiency.