AUSB中置曝气启动连续流全程自养脱氮工艺

Development of continuous flow CANON process in the middle-setting aerated AUSB reactor

摘要:

为优化连续流全程自养脱氮工艺的启动，在常温((25±1) ℃)下，于中置、底部曝气的两组AUSB(1#、2#)中比较连续流CANON工艺的启动过程，及不同氮负荷(NLR, R_NL)下脱氮性能的差异.结果表明：1#、2#分别于第55天、70天成功启动低氨氮(90 mg/L)CANON工艺; 在逐步提高NLR进程中，二者均在HRT=6 h工况下脱氮负荷(NRR, R_NR)达到该阶段最高水平，分别为0.280、0.256 kg/(m³·d); 实验后期，1#保持高效的脱氮状态，特征值(Δρ(TN)/Δρ(NO₃^--N))稳定在7.83，而2#运行125 d后特征值降至7.49，NOB活性增强.中置曝气AUSB结合同步亚硝化/厌氧氨氧化(SNA)和交替亚硝化/厌氧氨氧化(ANA)双重路径完成自养脱氮，得益于较高的好氧氨氧化菌(AOB)和厌氧氨氧化菌(AnAOB)活性，及对亚硝酸盐氧化菌(NOB)的有效抑制，实现了较高的总氮去除率，达74.98%(第140天).AUSB中置曝气可缩短连续流CANON工艺的启动时间，并实现长期稳定的自养脱氮.

Abstract:

To optimize the initiation of continuous flow CANON process, the research compared startup course and nitrogen removal performance under distinct NLR in room temperature ((25±1) ℃) between two sets of AUSB reactors, one of which was middle-setting aeration (1#), and the other was bottom-setting aeration (2#). The results showed that 1#, 2# successfully started CANON process treating domestic wastewater with relatively low ammonium concentration (90 mg/L) in 55 d and 70 d respectively. In the progress of increasing nitrogen loading rate gradually, both of them gained the highest nitrogen removal rate, which was 0.280 kg/(m³·d) for 1#, and 0.256 kg/(m³·d) for 2# under the condition of HRT=6 h. In later operation, 1# maintained efficient nitrogen removal status whose eigenvalue (Δρ(TN)/Δρ(NO₃^--N)) remained around 7.83, however, eigenvalue of 2# decreased to 7.49 after 125 d operation owing to the activity of NOB strengthened. The middle-setting aerated AUSB accomplished a higher total nitrogen removal rate which was 74.98% through the combination with simultaneous nitritation-Anammox (SNA) and alternate nitritation-Anammox (ANA) double pathways, which was ascribed to the enhancement of AOB and AnAOB activity and the effective suppression on NOB. Middle-setting aerated AUSB could shorten starting period of continuous flow CANON process, and furthermore realize long-term stable autotrophic nitrogen removal.