Abstract:

To achieve efficient nitrogen and phosphorus removal from domestic wastewater with low carbon to nitrogen ratio, a simultaneous partial nitritation and phosphorus removal (SPNPR) combined anaerobic ammonia oxidation (Anammox) system was established. Long-term operation performance, nutrient conversion route and microbial community structure of the system were investigated. The results indicated that desirable nitrogen and phosphorus removal performance was achieved in the 225-day experiment despite low temperatures, the average nitrogen and orthophosphate removal efficiencies were 90.7% and 94.2%, respectively. Orthophosphate and most of COD in domestic wastewater were removed in the SPNPR reactor, and the average nitrite accumulation ratio and nitrite/ammonium ratio in effluent were 97.2% and 1.23, respectively, this could provide suitable influent for Anammox reaction. Nitrogen in domestic wastewater was mainly removed by the Anammox biofilm reactor, in which Anammox played a major role, denitrification also accounted for 4.8% of the nitrogen removed. The main functional microorganisms in this reactor are Candidatus_Brocadia, denitrifying bacteria and bacteria that can decompose refractory organic matter. Nitrosomonas (2.27%) and phosphate accumulating organisms (5.27%) were dominant in the SPNPR reactor. Nitrite oxidizing bacteria were not detected. In addition, there were some psychrotolerant microorganisms with relatively high abundance, which could secrete cryoprotective extracellular polymeric substances (EPS) at low temperatures. These guaranteed the efficient SPNPR reaction. EPS component analysis further indicated that, the content of EPS increased significantly both in the two reactors at low temperatures, especially the tightly bound EPS with abundant protein, which is adjacent to cell and could protect microorganisms from environmental hazards such as low temperatures, promoting the stable and efficient operation of system.

Key words: wastewater, reactors, biofilm, efficient nitrogen and phosphorus removal, nutrient conversion route, microbial community structure, extracellular polymeric substances

摘要：

为实现低碳氮比生活污水高效脱氮除磷，构建了部分短程硝化同步除磷(SPNPR)耦合Anammox系统，探究了其长期运行性能、污染物转化路径和菌群结构。结果表明，系统脱氮除磷效果良好，且低温时可稳定维持，平均总氮和PO₄^3--P去除率分别为90.7%和94.2%。PO₄^3--P与大部分COD被SPNPR反应器去除，同时其可为Anammox提供合适的进水NH₄⁺-N和NO₂^--N。氮主要被Anammox生物膜反应器去除，其中Anammox发挥主要作用，并存在一定的反硝化作用，该反应器中主要功能微生物为Candidatus_Brocadia、反硝化菌和可分解难降解有机物的菌属。SPNPR反应器中Nitrosomonas与聚磷菌的丰度较高，未检测到亚硝酸盐氧化菌，并存在丰度较高的耐寒菌属，其可在低温时产生防冷冻的胞外聚合物(EPS)，保证了反应器良好的SPNPR作用。EPS分析发现，低温时反应器中EPS含量大幅增加，尤其是紧密结合型EPS，其可减缓低温等对微生物的危害，促进系统稳定运行。

关键词: 污水, 反应器, 生物膜, 高效脱氮除磷, 污染物转化路径, 菌群结构, 胞外聚合物