低温对CANON型序批式生物膜反应器脱氮的影响

探究了4种低温水平下基于亚硝化的全程自养脱氮（CANON）型序批式生物膜反应器（SBBR）的运行效果及其氮素转化机制.结果表明，当CANON型SBBR在不同的低温水平下稳定运行后，其脱氮微生物优势菌群发生了不同程度的变化，随之改变了系统的氮素转化途径及其脱氮性能.当温度>15℃时，SBBR中AOB和anammox菌的丰度与活性未受到明显抑制，CANON作用始终是系统脱氮的主要途径，SBBR对TN的平均去除率亦较为理想；而当温度<15℃时，anammox菌的丰度与活性在10，5℃下分别出现不同程度的降低，进而改变了SBBR的氮素转化途径，使其脱氮性能出现不同程度的恶化.在10℃时，NOB的增殖及其活性的提高使硝化/反硝化作用取代CANON作用成为SBBR脱氮的主要途径，此时系统对TN的去除率骤降至（16.87±4.79）%；在5℃时，反硝化过程中第1步还原反应的停滞与反硝化菌对NO₂^--N利用率的提高使SBBR中氮素的去除依赖于CANON作用和短程硝化/反硝化作用的协同，系统对TN的去除率为（54.83±3.68）%.

Effect of low temperature on nitrogen removal in a sequencing batch biofilm reactor with CANON process

The treatment performance and underlying molecular mechanisms of nitrogen transformation in a sequencing batch biofilm reactor (SBBR) with the complete autotrophic nitrogen removal over nitrite (CANON) process were investigated at four different low temperatures in this study. After each system achieved the stable stutus in the low temperature environment, different low temperatures resulted in different degrees of variations in the nitrogen removal performance and transformation pathways of the SBBRs, which was mainly because the original dominant bacterial communities for nitrogen removal in the system changed with the temperature during the operation. When the temperature was above 15℃, the abundances and activities of aerobic ammonia oxidizing bacteria (AOB) and anammox bacteria in the SBBR had not been significantly inhibited, the CANON process was the dominant methanism in the nitrogen removal, and the ideal average removal rates of total nitrogen were also achieved. When the temperature was below 15℃, the abundance and activitity of anammox bacteria experienced different degrees of reduction at 10 and 5℃, which led to the change of main pathway for nitrogen transformation in SBBRs, thus the various degrees of deterioration in the nitrogen removal performance. At 10℃, the proliferation and increased activities of nitrite oxidizing bacteria (NOB) made the nitrification/denitrification process replaced CANON to become the primary route of TN removal in the SBBR with the TN removal efficiency of the system declined to (16.87±4.79)%. At 5℃, the stagnation of reduction process in the 1^st stage of denitrification and the increased capacity of denitrifiers to compete for NO₂^--N caused the removal of nitrogen in SBBR to rely on both the CANON process and the nitrification/denitrification process. The nitrogen removal rate at this status was (54.83±3.68)% in the system.