基于颗粒污泥的短程反硝化USB反应器启动和运行研究

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%).