iBET - Instituto de Biologia Experimental e Tecnológica, Av. República, Qta. do Marquês, 2780-157 Oeiras, Portugal; ITQB - Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Quinta do Marquês, 2780-157 Oeiras, Portugal.
LAQV-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Portugal.
Sci Total Environ. 2019 Feb 15;651(Pt 2):2460-2472. doi: 10.1016/j.scitotenv.2018.10.132. Epub 2018 Oct 11.
Few attempts have been made in previous studies to link the microbial community structure and function with nitrous oxide (NO) emissions at full-scale wastewater treatment plants (WWTPs). In this work, high-throughput sequencing and reverse transcriptase-qPCR (RT-qPCR) was applied to activated sludge samples from three WWTPs for two seasonal periods (winter and summer) and linked with the NO emissions and wastewater characteristics. The total NO emissions ranged from 7.2 to 937.0 g N-NO/day, which corresponds to an emission factor of 0.001 to 0.280% of the influent NH-N being emitted as NO. Those emissions were related to the abundance of Nitrotoga, Candidatus Microthrix and Rhodobacter genera, which were favored by higher dissolved oxygen (DO) and nitrate (NO) concentrations in the activated sludge tanks. Furthermore, a relationship between the nirK gene expression and NO emissions was verified. Detected NO emission peaks were associated with different process events, related to aeration transition periods, that occurred during the regular operation of the plants, which could be potentially associated to increased emissions of the WWTP. The design of mitigation strategies, such as optimizing the aeration regime, is therefore important to avoid process events that lead to those NO emissions peaks. Furthermore, this study also demonstrates the importance of assessing the gene expression of nosZ clade II, since its high abundance in WWTPs could be an important key to reduce the NO emissions.
先前的研究中，很少有尝试将微生物群落结构和功能与全规模污水处理厂（WWTP）的氧化亚氮（NO）排放联系起来。在这项工作中，高通量测序和逆转录实时定量聚合酶链反应（RT-qPCR）被应用于三个 WWTP 的活性污泥样品，进行了两个季节性时期（冬季和夏季）的研究，并与 NO 排放和废水特性相关联。总 NO 排放量范围为 7.2 至 937.0 g N-NO/天，这对应于作为 NO 排放的进水 NH-N 的 0.001 至 0.280%的排放因子。这些排放与 Nitrotoga、Candidatus Microthrix 和 Rhodobacter 属的丰度有关，这些属在活性污泥池中较高的溶解氧（DO）和硝酸盐（NO）浓度下得到了促进。此外，还验证了 nirK 基因表达与 NO 排放之间的关系。检测到的 NO 排放峰值与在工厂正常运行过程中发生的不同工艺事件有关，这些事件与曝气转换时期有关，这可能与 WWTP 的排放量增加有关。因此，设计缓解策略（如优化曝气制度）非常重要，以避免导致这些 NO 排放峰值的工艺事件。此外，本研究还表明了评估 nosZ 类 II 基因表达的重要性，因为其在 WWTP 中的高丰度可能是减少 NO 排放的重要关键。
