Start-Up of Denitrifying Dephosphatation with Nitrite as Electron Acceptor and Microbial Community Analysis

The two-stage mode was used to start up the denitrifying dephosphatation system with nitrite as electron acceptor, and the systems capability of denitrifying dephosphatation was evaluated. Phosphate-accumulating organisms were enriched under the anaerobic/aerobic condition at the first stage. Then change the condition to anaerobic/anoxic so that denitrifying phosphate-accumulating organisms (DPAO) using NO2-N as electron acceptor can be selected. The fast start-up of this system was achieved after 120 days, and the system has a good capability of denitrifying dephosphatation. The average TN and TP in the effluent were 5.39 mg/L and 1.55 mg/L with removal rates of 82.5% and 80.0%, respectively. PCR-DGGE results showed that microbial population changed in the process of domestication, while the structure of microbial community changed little in the stable stage, indicating relatively stable microbial community structure had formed after the domestication.