(O/A)n运行模式对同步硝化内源反硝化除磷工艺脱氮除磷效果的影响

Impact of (O/A)n operation on nitrogen and phosphorus removal performance of a simultaneous nitrification and endogenous denitrification phosphorus removal system

关键词:  同步硝化内源反硝化除磷  反硝化聚磷菌  反硝化聚糖菌  (O/A)n  高通量测序

Key words:  simultaneous nitrification endogenous denitrification and phosphorus removal(SNEDPR)  denitrifying polyphosphate accumulating bacteria (DPAOs)  denitrifying polysaccharide bacteria (DGAOs)  (O/A)_n  high throughput sequencing

摘要:

为强化反硝化除磷技术中反硝化聚磷菌(DPAOs)与反硝化聚糖菌(DGAOs)的协同作用,实验设置3组同规格SBR反应器R1~R3,以n值分别为1、2、3的周期性好氧/缺氧(O/A)_n曝气模式运行同步硝化内源反硝化除磷(SNEDPR)系统,通过对比3组反应器70 d的运行情况,探究各系统污染物处理性能和功能菌活性。结果表明:在厌氧阶段内碳源储存量相似的条件下,采用(O/A)₃运行的R3反应器在第71天的出水TN、TP 和COD去除率分别达89.38%、91.78%和90.20%,表现出最佳的污染物去除效果,缺氧阶段的TP去除率也更高；典型周期显示,第70天3组反应器最后一个好氧段末NO-₂-N占总氮的质量分数分别为42.41%、49.83%和52.33%,证实提高(O/A)_n运行的n值后,系统亚硝酸盐转化率(NTR,R_NT)提高；污泥特性分析表明,R3反应器中MLSS和MLVSS增长平稳,SVI值较低,单位VSS EPS质量分数在第70天达85.27 mg/g,显示出良好的污泥结构和沉降性能；微生物群落分析显示,R3中DPAOs和DGAOs的相对丰度更高,表明增加(O/A)_n的曝气周期有利于功能菌的富集;提高(O/A)_n运行的n值可以有效增强DPAOs和DGAOs的协同作用,提高SNEDPR系统的脱氮除磷效率,并减少对外部碳源的依赖。

Abstract:

To enhance the synergistic effects of denitrifying phosphate accumulating organisms (DPAOs) and denitrifying glycogen accumulating organisms (DGAOs) in the denitrification phosphorus removal technology, three identical SBR reactors (R1, R2, R3) were set up in the experiment. These reactors operated under a periodic aerobic/anoxic (O/A)_n aeration mode with n values of 1,2, and 3, respectively, to run a simultaneous nitrification endogenous denitrification and phosphorus removal (SNEDPR) system. By comparing the operational conditions of the three reactors over 70 days, the pollutant treatment performance and the activity of functional bacteria were investigated. The results show that under the condition of similar internal carbon storage during the anoxic phase, the R3 reactor operated with (O/A)₃ achieved the highest pollutant removal rates on the 71st day, with 89.38% for total nitrogen (TN), 91.78% for total phosphorus (TP), and 90.20% for chemical oxygen demand (COD), demonstrating the best pollutant removal effect, and also had a higher TP removal rate during the anoxic phase. The typical cycles indicated that on the last aerobic stage of the 70st day, the ratio of NO-₂-N to total nitrogen was 42.41%, 49.83%, and 52.33%, respectively, confirming that increasing the n value in (O/A)_n operation enhances the system′s NTR. Analysis of sludge characteristics revealed that in the R3 reactor, MLSS(mixed liquor suspended solids) and MLVSS(mixed liquor volatile suspended solids) increased steadily, with a low SVI(sludge volume index). The unit VSS extracellular polymeric substances (EPS) content reached 85.27 mg/g by the 70st day, indicating good sludge structure and settling performance. Microbial community analysis showed a higher relative abundance of DPAOs and DGAOs in R3, suggesting that increasing the aeration cycle of (O/A)_n is beneficial for the enrichment of functional bacteria. Increasing the n value in (O/A)_n operation can effectively enhance the synergistic action between DPAOs and DGAOs, improve the nitrogen and phosphorus removal efficiency of the SNEDPR system, and reduce the reliance on external carbon sources.