• Bi-Bio-Selector for nitrogen and phosphorus removal (BBSNP) process was investigated. • The desired effluent quality was achieved by BBSNP at low temperature and low C/N. • High MLSS was a practical way to solve low nitrifying efficiency at low temperature. • DPAOs played significant roles in TN and TP removal at BBSNP process. • Dechloromonas was in higher amount than other DPAOs in the BBSNP process. For solving the nutrient removal from urban domestic sewage at low temperature and low C/N ratio, the full-scale Bi-Bio-Selector for Nitrogen and Phosphorus removal (BBSNP) process was set in Shanghai, China and run continuously at C/N about 3.6. It was run for 133 days along with the temperature dropping from 22 ± 2℃ to 10 ± 2℃. After 27 days' operation, the performance of BBSNP process reached to stable. Chemical oxygen demand (COD), NH 4 +-N, total nitrogen (TN) and total phosphorus (TP) in effluent were lower than 40, 0.5, 8 and 0.1 mg/L, respectively. The NH 4 +-N and TN removal efficiency were influenced and decreased at low temperature (10 ± 2℃). After improving mixed liquor suspended solids (MLSS) from 4000 mg/L to 6000 mg/L, the nitrogen removal efficiency lifted to previous level because of the increasing NH 4 +-N and NO 2 −-N oxidation rate of suspended sludge. Denitrifying phosphorus accumulating organisms (DPAOs) were the dominant bacteria responsible for phosphorous removal in this study. The Denitrifying phosphorus removal (DPR) efficiency was as high as 74.16 ± 4.40%. Dechloromonas was in higher amount than other DPAOs in the BBSNP process. The results of this study provided a convincing evident that BBSNP could be a practical and cost-effective process for removing nutrient from urban domestic sewage. [ABSTRACT FROM AUTHOR]