School of Water and Environment, Chang'an University, Xi'an, 710064, Shaanxi, China; Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region (Chang'an University), Ministry of Education, Xi'an, 710064, Shaanxi, China.
School of Water and Environment, Chang'an University, Xi'an, 710064, Shaanxi, China; Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region (Chang'an University), Ministry of Education, Xi'an, 710064, Shaanxi, China.
J Environ Manage. 2022 Aug 15;316:115237. doi: 10.1016/j.jenvman.2022.115237. Epub 2022 May 11.
NO and NO as important greenhouse gases andtheir production mechanisms during nitrification are not completely understood. This study aimed to analyze the effect of hydroxylamine (NHOH) on NO and NO produced by nitrifying bacteria from activated sludge in a sequencing batch reactor (SBR). Experimental results showed that when nitrite (NO) accumulated during aerobic ammonia (NH) oxidation, NO was the main product. The total amount of NO and NO produced by NHOH oxidation was positively correlated with dissolved oxygen (DO) levels. The imbalance of NH oxidation caused by NHOH addition was more conducive to the generation of NO and NO under high DO conditions. When NHOH was added into the reactor with NO as the substrate, the production of NO and NO under high DO levels was mainly related to NHOH oxidation. Under low DO conditions, NO and NO from the biotic/abiotic hybrid pathways were more significant in the reactor of the coexistence of NO and NHOH, which could be mainly caused by the pathways of nitrifier denitrification and abiotic reaction. Besides, limited amount of NO and NO was generated by heterotrophic denitrification pathway during autotrophic nitrification. The implications for the above results are important for understanding the production of NO and NO under NHOH stress in nitrifying sludge reactor.
作为重要的温室气体，NO 和 NO 的产生机制在硝化过程中尚未完全明晰。本研究旨在分析羟胺（NHOH）对好氧氨氧化阶段序批式反应器（SBR）中活性污泥硝化菌产生的 NO 和 NO 的影响。实验结果表明，当亚硝酸盐（NO ）在有氧氨（NH ）氧化阶段积累时，NO 是主要产物。NHOH 氧化产生的 NO 和 NO 总量与溶解氧（DO）水平呈正相关。NHOH 会打破 NH 氧化的平衡，在高 DO 条件下更有利于生成 NO 和 NO 。当向以 NO 为底物的反应器中添加 NHOH 时，高 DO 水平下 NO 和 NO 的生成主要与 NHOH 氧化有关。在低 DO 条件下，NO 和 NO 主要来自于共存的 NO 和 NHOH 中的生物/非生物混合途径，这可能主要是由硝化菌反硝化和非生物反应途径引起的。此外，自养硝化过程中的异养反硝化途径生成的 NO 和 NO 量有限。这些结果对于理解硝化污泥反应器中 NHOH 胁迫下 NO 和 NO 的产生具有重要意义。
