State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, People's Republic of China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, People's Republic of China.
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, People's Republic of China.
Chemosphere. 2021 Jan;263:128184. doi: 10.1016/j.chemosphere.2020.128184. Epub 2020 Aug 29.
A lab-scale anaerobic-anoxic-oxic system was used to investigate the nitrogen removal mechanism under low dissolved oxygen (DO) conditions. When DO was decreased from 2 to 0.5 mg L, chemical oxygen demand (COD) and NH removals were not influenced, while total nitrogen removal increased from 69% to 79%. Further batch tests indicated that both the specific nitrification rate and denitrification rate greatly increased under low DO conditions. When DO was decreased from 2 to 0.5 mg L, the oxygen half saturation constant value for ammonia oxidizing bacteria (AOB) decreased from 0.39 to 0.29 mg-O L, and for nitrite oxidizing bacteria (NOB), it reduced from 0.29 to 0.09 mg-O L. Correspondingly, the observed yield coefficients increased from 0.05 to 0.10 mg-cell mg-N for AOB, and from 0.02 to 0.06 mg-cell mg-N for NOB. High-throughput sequencing revealed that the relative abundances of AOB increased from 6.13% to 6.54%, Nitrospira-like NOB increased from 3.67% to 6.50%, and denitrifiers increased from 2.84% to 7.04%. Improved simultaneous nitrification and denitrification under low DO conditions contributed to the enhanced nitrogen removal.
采用实验室规模的厌氧-缺氧-好氧系统，研究了低溶解氧（DO）条件下的脱氮机制。当 DO 从 2 降至 0.5mg/L 时，COD 和 NH 的去除不受影响，而总氮去除率从 69%提高到 79%。进一步的分批试验表明，低 DO 条件下，硝化和反硝化的比速率均显著提高。当 DO 从 2 降至 0.5mg/L 时，氨氧化菌（AOB）的氧半饱和常数从 0.39 降至 0.29mg-O/L，亚硝酸盐氧化菌（NOB）从 0.29 降至 0.09mg-O/L。相应地，AOB 的观察产率系数从 0.05 增至 0.10mg-细胞 mg-N，NOB 从 0.02 增至 0.06mg-细胞 mg-N。高通量测序结果表明，AOB 的相对丰度从 6.13%增至 6.54%，类似 Nitrospira 的 NOB 从 3.67%增至 6.50%，反硝化菌从 2.84%增至 7.04%。低 DO 条件下同步硝化反硝化的改善有助于提高氮去除率。
