Zhang Kuo, Li Xinjue, Ni Shou-Qing, Liu Sitong
Department of Environmental Sciences and Engineering, College of Environmental Sciences and Engineering, Peking University, Beijing, China.
Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, China.
Front Bioeng Biotechnol. 2022 Mar 21;10:851565. doi: 10.3389/fbioe.2022.851565. eCollection 2022.
Practical application of the partial nitritation-anaerobic ammonium oxidation (anammox) process has attracted increasing attention because of its low operational costs. However, the nitritation process, as a promising way to supply nitrite for anammox, is sensitive to the variations in substrate concentration and dissolved oxygen (DO) concentration. Therefore, a stable supply of nitrite becomes a real bottleneck in partial nitritation-anammox process, limiting their potential for application in mainstream wastewater treatment. In this study, five 18-L sequencing batch reactors were operated in parallel at room temperature (22°C ± 4°C) to explore the nitritation performance with different carrier materials, including sepiolite-nonwoven carrier (R1), zeolite-nonwoven carrier (R2), brucite-nonwoven carrier (R3), polyurethane carrier (R4), and nonwoven carrier (R5). The ammonia oxidation rate (AOR) in R1 reached the highest level of 0.174 g-N L d in phase II, which was 1.4-fold higher than the control reactor (R4). To guarantee a stable supply of nitrite for anammox process, the nitrite accumulation efficiency (NAE) was always higher than 77%, even though the free ammonia (FA) decreases to 0.08 mg-N/L, and the pH decreases to 6.8 ± 0.3. In phase V, the AOR in R1 reached 0.206 g-N L d after the DO content increase from 0.7 ± 0.3 mg/L to 1.7 ± 0.3 mg/L. The NAE in R1 was consistently higher than 68.6%, which was much higher than the other reactor systems (R2: 43.8%, R3: 46.6%, R4: 23.7%, R5: 22.7%). Analysis of 16S rRNA gene sequencing revealed that the relative abundance of and in R1 was significantly lower than other reactors, indicating that the sepiolite carrier plays an important role in the inhibition of nitrite-oxidizing bacteria. These results indicate that the sepiolite nonwoven composite carrier can effectively improve the nitritation process, which is highly beneficial for the application of partial nitritation-anammox for mainstream wastewater treatment.
由于运行成本低，部分亚硝化-厌氧氨氧化（anammox）工艺的实际应用受到越来越多的关注。然而，作为一种为anammox提供亚硝酸盐的有前景的方法，亚硝化过程对底物浓度和溶解氧（DO）浓度的变化很敏感。因此，稳定供应亚硝酸盐成为部分亚硝化-anammox工艺的真正瓶颈，限制了它们在主流废水处理中的应用潜力。在本研究中，五个18升的序批式反应器在室温（22°C±4°C）下并行运行，以探索不同载体材料的亚硝化性能，包括海泡石-无纺布载体（R1）、沸石-无纺布载体（R2）、水镁石-无纺布载体（R3）、聚氨酯载体（R4）和无纺布载体（R5）。R1中的氨氧化速率（AOR）在第二阶段达到最高水平，为0.174 g-N L d，比对照反应器（R4）高1.4倍。为了保证为anammox工艺稳定供应亚硝酸盐，即使游离氨（FA）降至0.08 mg-N/L且pH降至6.8±0.3，亚硝酸盐积累效率（NAE）始终高于77%。在第五阶段，当溶解氧含量从0.7±0.3 mg/L增加到1.7±0.3 mg/L后，R1中的AOR达到0.206 g-N L d。R1中的NAE始终高于68.6%，远高于其他反应器系统（R2：43.8%，R3：46.6%，R4：23.7%，R5：22.7%）。16S rRNA基因测序分析表明，R1中 和 的相对丰度明显低于其他反应器，表明海泡石载体在抑制亚硝酸盐氧化细菌方面发挥着重要作用。这些结果表明，海泡石无纺布复合载体可以有效改善亚硝化过程，这对部分亚硝化-anammox在主流废水处理中的应用非常有利。
