解偶联剂邻氯苯酚作用下活性污泥微生物群落结构的演替规律研究

投加解偶联剂邻氯苯酚可以实现活性污泥系统的污泥减量，但邻氯苯酚长时间作用下系统中微生物群落结构及多样性的变化尚不清楚.因此，本研究利用2个序批式反应器（SBR）进行了63 d的实验，考察了未投加邻氯苯酚（R_A）和投加10 mg·L^-1邻氯苯酚（R_B）条件下，活性污泥系统中基质去除特性及微生物群落结构的变化规律.研究结果表明，投加10 mg·L^-1的邻氯苯酚使得污泥减量达41.3%，COD平均去除率下降10.4%.氨氮去除率在实验前期持续下降，在第28 d时下降至82.3%，而后逐渐恢复到93.2%.高通量测序结果表明，投加邻氯苯酚后系统中微生物丰度及多样性逐渐降低.R_B系统中主导菌门Proteobacteria的相对丰度一直保持在50%以上.硝化菌属中Nitrosomonas和Nitrospira的相对丰度最高降低了约88.3%和100%（第28 d），但在实验后期有所恢复.在第63 d，R_B系统中絮凝菌Zoogloea的相对丰度下降了98.2%，而丝状菌Meganema丰度增加至33.8%，这导致系统污泥沉降性能略有下降.此外，Dokdonella的相对丰度由0.68%增加至1.33%，而Paracoccus的相对丰度增加了近36倍，这些参与难降解有机物的功能菌增加说明其可能参与了邻氯苯酚的降解.本研究结果对于解析解偶联剂长时间作用下活性污泥微生物的响应机制具有重要的指导意义.

Evolution of microbial community structure in activated sludge under the exposure of uncoupler o-chlorophenol

The dosage of uncoupler o-chlorophenol has been proved effective in sludge reduction in activated sludge systems. However, the changes of microbial community structure and diversity in activated sludge under long-period of o-chlorophenol exposure are still unclear. In this study, the substrate removal efficiency and microbial community shift of activated sludge systems in the absence and prensence of o-chlorophenol dosage (R_A) were investigated in two parallel sequential batch reactors (SBR) for 63 days. The results showed that sludge reduction could reach about 41.3% at an o-chlorophenol dose of 10 mg·L^-1. The average COD removal efficiency in R_B decreased by 10.4% compared with R_A. The ammonia nitrogen removal efficiency in R_B declined steadily and was reduced to 82.3% in day 28, but recovered gradually to 93.2% at the end of the experiment. High-throughput sequencing analysis results showed that the richness and diversity of microorganisms in activated sludge system decreased in the exposure to o-chlorophenol. The relative abundance of the dominant phylum in R_B, i.e., Proteobacteria, has been keeping above 50% during the experiment. The relative abundance of nitrifying bacteria, e.g., Nitrosomonas and Nitrospira declined up to~88.3% and 100% in day 28, but recovered gradually in later period of the experiment. In day 63, the relative abundance of flocculation bacteria Zoogloea decreased about 98.2%, while the relative abundance of filamentous bacteria Meganema increased to 33.8%, resulting in the deterioration of sludge settleability. In addition, the relative abundance of Dokdonella increased from 0.68% to 1.33% and the abundance of Paracoccus had experienced an increase about 36 times. These functional strains which can participate in the degradation of refractory organics suggested their potential roles in participating in the degradation of o-chlorophenol. The above results provide important information for exploring the response mechanisms of activated sludge microorganism in exposure to uncouplers in a long period.