基于颗粒污泥的短程反硝化USB反应器启动和运行研究

在2个相同的USB反应器(R1无载体,R2采用多孔生物填料为载体)中构建了短程反硝化工艺,对R1和R2NO₃^--N→NO₂^--N转化性能、短程反硝化颗粒污泥物化特性、胞外聚合物(EPS)产生特性以及微生物功能菌群主要特征进行差异分析.结果表明,反应器运行81d,氮负荷(NLR)为1.2kg/(m³·d)时,NO₃^--N→NO₂^--N转化率(NTR) R2(85%)高于R1(80%);载体颗粒污泥(R2)沉降性能优于自固定化颗粒污泥(R1)且载体颗粒污泥(R2)更容易截留EPS,PN/PS值R1(1.29)>R2(1.15),污泥体积指数(SVI) R1(27.07mL/g MLSS)>R2(19.36mL/g MLSS);扫描电镜发现R1污泥表面聚集长杆菌,R2污泥表面聚集短杆菌和球菌,与R1相比R2颗粒污泥结构更加规则密实.微生物高通量测序结果表明,R2物种丰富度和多样性高于R1,变形菌门、拟杆菌门和绿弯菌门在短程反硝化系统中占主导地位,R1和R2主要NO₂^--N积累功能菌属均为Acinetobacter属(R1-59.18%、R2-46.04%)和Thauera属(R1-6.81%、R2-5.99%).

Study on start-up and operation of USB reactor for partial denitrification based on granular sludge

In this study, the partial denitrification process was constructed in two identical Up-flow Sludge Bed reactors (R1 without the carrier, R2 with porous biological carrier). The transformation performance of nitrate-to-nitrite, the physicochemical characteristics of partial denitrification granular sludge, the production characteristics of extracellular polymeric substances (EPS), and the dominant characteristics of functional bacteria genera were compared and analyzed. The NO₃^--N→NO₂^--N transformation ratio(NTR) in R2 (85%) was higher than that of R1(80%) when the reactors ran for 81 days and the nitrogen loading rates (NLR) was 1.2kg/(m³·d). The sedimentation performance of carrier granular sludge (R2) was better than that of self-immobilized granular sludge (R1), and the carrier granular sludge in R2 was easier to capture EPS. The PN/PS value of R1 (1.29) was greater than that of R2 (1.15), and the sludge volume index (SVI) of R1(27.07mL/g MLSS) was also greater than that of R2 (19.36mL/g MLSS). Under scanning electron microscopy, it was found that Long bacillus gathered on the surface of R1 sludge, while short-bacillus and coccus were observed on the surface of R2 sludge. In comparison, the structure of granular sludge in R2 was more regular and dense than that in R1. Microbial high throughput sequencing showed that the species richness and diversity of R2 were higher than that of R1. Proteobacteria, Bacteroides, and Chlorocurvate were dominant in the partial denitrification system. The main NO₂^--N accumulating genera in both R1 and R2 were Acinetobacter(R1 accounted for 59.18% and R2 accounted for 46.04%) and Thaurea (R1 accounted for 6.81% and R2 accounted for 5.99%).