State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
J Environ Sci (China). 2024 Jan;135:210-221. doi: 10.1016/j.jes.2023.01.002. Epub 2023 Jan 7.
Mainstream partial nitritation-anammox (PNA) process easily suffers from performance instability and even reactor collapse in application. Thus, it is of great significance to unveil the characteristic of performance recovery, understand the intrinsic mechanism and then propose operational strategy. In this study, we combined long-term reactor operation, batch tests, and metagenomics to reveal the succession of microbial community and functional metabolism variation from system collapse to recovery. Proper aeration control (0.10-0.25 mg O/L) was critical for performance recovery. It was also found that Candidatus Brocadia became the dominant flora and its abundance increased from 3.5% to 11.0%. Significant enhancements in carbon metabolism and phospholipid biosynthesis were observed during system recovery, and the genes abundance related to signal transduction was dramatically increased. The up-regulation of sdh and suc genes showed the processes of succinate dehydrogenation and succinyl-CoA synthesis might stimulate the production of amino acids and the synthesis of proteins, thereby possibly improving the activity and abundance of AnAOB, which was conducive to the performance recovery. Moreover, the increase in abundance of hzs and hdh genes suggested the enhancement of the anammox process. Changes in the abundance of key genes involved in nitrogen metabolism indicated that nitrogen removal pathway was more diverse after system recovery. The achievement of performance recovery was driven by anammox, nitrification and denitrification coupled with dissimilatory nitrate reduction to ammonium. These results provide deeper insights into the recovery mechanism of PNA system and also provide a potential regulation strategy for the stable operation of the mainstream PNA process.
主流部分亚硝化-厌氧氨氧化（PNA）工艺在应用中容易出现性能不稳定，甚至反应器崩溃的情况。因此，揭示性能恢复的特征，了解内在机制，然后提出操作策略具有重要意义。本研究结合长期反应器运行、批处理试验和宏基因组学，揭示了从系统崩溃到恢复过程中微生物群落和功能代谢变化的演替。适当的曝气控制（0.10-0.25mg O/L）对性能恢复至关重要。还发现，Candidatus Brocadia 成为优势菌群，其丰度从 3.5%增加到 11.0%。在系统恢复过程中观察到碳代谢和磷脂生物合成的显著增强，与信号转导相关的基因丰度显著增加。sdh 和 suc 基因的上调表明琥珀酸脱氢酶和琥珀酰辅酶 A 合成过程可能刺激氨基酸的产生和蛋白质的合成，从而可能提高 AnAOB 的活性和丰度，这有利于性能恢复。此外，hzs 和 hdh 基因丰度的增加表明厌氧氨氧化过程得到了增强。参与氮代谢的关键基因丰度的变化表明，系统恢复后脱氮途径更加多样化。性能恢复的实现是由厌氧氨氧化、硝化和反硝化与异化硝酸盐还原为铵耦合驱动的。这些结果深入了解了 PNA 系统恢复的机制，并为主流 PNA 工艺的稳定运行提供了潜在的调控策略。
