Employed a SBR to simulate municipal wastewater as the influent matrix and initiated the Nitritation-Enhanced Partial Denitrification-Complete Autotrophic Nitrogen Removal Over Nitrite(N-EPD-CANON)process. The anoxic duration within the EPD system was meticulously adjusted to scrutinize the impact on endogenous nitrite accumulation and the consequent performance alterations within the CANON system. The objective was to elucidate the influence of anoxic time on endogenous nitrite concentration and its subsequent effects on nitrogen removal efficiency, the activity of functional microbial groups, and the structure of microbial communities within the CANON process. The findings revealed that an anoxic duration of 40minutes within the EPD system was optimal for capturing influent organic matter while concurrently promoting the endogenous nitrite to accumulate at a favorable concentration of approximately 4mg/L. Under sustained operational conditions, the CANON reactor achieved a total nitrogen removal rate of 86.43%. The specific anammox activity(SAA)was determined to be 0.82gN/(gVSS·d), the particular nitrate production rate(SNPR)was reduced to 0.28gN/(gVSS·d), and the specific ammonium removal rate(SAOR)was recorded at 0.70gN/(g VSS·d). Additionally, the application of 3D-EEM and PARAFAC techniques to analyze the fluorescence components of EPS in the sludge indicated that the intensification of endogenous nitrite had a beneficial effect on increasing the content of aromatic proteins within the EPS without altering its composition. Microbiota community analysis reveals that Candidatus_Competibacter is the dominant genus in the EPD system, accounting for 24.61%. In contrast, in the CANON system, the relative abundance of Nitrosomonas at 2.67% ensures the NO2--N supply for AnAOB, and Candidatus Brocadia, as the main genus of AnAOB, accounts for 13.34%.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |