RAPID STARTUP OF EGSB-PDA PROCESS BY USING ANAMMOX GRANULAR SLUDGE

Abstract

 In recent years, the PDA process, a new nitrogen removal method combining the partial denitrification (PD) reaction and the anammox reaction, has attracted attention worldwide. In this study, focusing on the existence of denitrifying bacteria in anammox sludge, we investigated the possibility of starting up the PDA process using anammox sludge. Moreover, the treatment effect of the PDA process was studied and the microbial composition of granule sludge was analyzed by 16S rRNA gene sequencing. As a result, by controlling the COD/NO₃-N ratio, the EGSB continuous-flow PDA process was successfully started up quickly. Furthermore, the PDA process achieved a high nitrogen removal rate of 99% when treating low-strength nitrogen wastewater. In addition, based on the result of specific activity test for nitrate reduction, nitrite reduction and anammox reaction and the analysis of changes in microbial community structure, we found that the nitrate reduction rate and the nitrite accumulation rate increased, and the dominant species in anammox granule sludge changed from AnAOB and denitrifying bacteria to AnAOB and Thauera, indicating that the PDA process had been successfully started up.