| The effect of aeration densities (3, 6, 12) on the CANON process start-up were investigated in R1, R2, and R3 inoculated mature anaerobic ammonium oxide granule sludge under the same conditions of aeration and aeration/anaerobic time ratio (1:1) at 25℃. The results showed that R1, R2, and R3 of the CANON process were initiated in 32, 29, and 23 d, respectively. A greater aeration density promoted the start-up of the CANON process. In the cycle test, the pH of R1, R2, and R3 decreased by 0.4, 0.55, and 1.06, respectively. R3 exhibited excellent denitrification performance due to its large aeration density and suitable time interval, which increased system efficiency in DO and better inhibited NOB activity. According to the denitrification route analysis, there were two denitrification pathways of ANA and SNA in the system. The proportion of SNA was 19.3%, 24.5%, and 33.6%, respectively. With the increase in aeration density, the contribution of SNA increased gradually. |
