污水处理厂微生物群落结构及胞外聚合物组分分析

发布时间：2018-06-21 02:45

本文选题：A2/O工艺 + 微生物群落结构　；参考：《重庆大学》2015年硕士论文

【摘要】：A2/O工艺是一种常用的污水生物处理工艺。在污水生物处理系统中,污染物的去除过程本质上是微生物自身的的代谢过程。微生物的种类、数量及群落结构的演替直接影响系统对污染物的去除。因此,对污水生物处理系统中微生物群落结构的研究显得尤为必要。本研究采用Mi Seq高通量技术对城市污水厂厌氧、缺氧和好氧污泥样品进行了DNA测序,结果表明:系统中微生物种类繁多,多样性较高。好氧池和厌氧池中,优势菌门是Proteobacteria(最优势菌门)、Firmicutes、Bacteroidetes和Chloroflexi;缺氧池中优势菌门为Bacteroidetes(最优势菌门),Planctomycetes、Proteobacteria、Acidobacteria和Firmicutes。三种污泥样品中最优势菌属均为Terrimonas。整个系统中硝化细菌群落结构较为单一,AOB只有Nitrosomonas,NOB只有Nitrospira。而反硝化细菌多样性高,好氧池中存在大量好氧反硝化细菌,整个系统的自养反硝化细菌数量极少。EPS是活性污泥絮体的重要组成部分,它可以吸附污水中的金属离子[1]和有机污染物[2],对微生物聚集体的形成和结构的维持具有重要作用[3],还可以保护微生物减小外部不利环境的冲击。本研究采用超声法提取城市污水处理厂和高盐废水处理系统活性污泥中的EPS,并测定其中蛋白质和多糖的含量,发现蛋白质为EPS的主要成分。红外光谱和三维荧光光谱证明了EPS中蛋白质和多糖的存在,还发现高盐厌氧池的EPS中可能存在腐殖酸。聚集沉降实验结果表明,EPS有利于污泥聚集,且好氧污泥的EPS比厌氧污泥的EPS对污泥聚集的作用大,高盐厌氧池的EPS对污泥的聚集影响很小。胞外蛋白作为EPS的主要成分,其性质很大程度上决定了EPS的性质,进而影响污泥聚体的特性和功能。用基于LC-MS/MS技术的鸟枪法对污水处理厂活性污泥中的胞外蛋白进行鉴定。根据基因本体论注释(GOA)分别对厌氧、缺氧和好氧污泥中鉴定出的130、108和114种胞外蛋白进行分类,结果表明,三种污泥的胞外蛋白参与的生物过程、主要来源和分子功能都基本相同。胞外蛋白主要来源于细胞溶解,参与最多的都是代谢过程、细胞加工过程和单一生物体过程,主要的分子功能是催化活性和结合活性。说明胞外蛋白具有催化、降解和结合多价阳离子与有机分子的潜在功能。厌氧污泥和好氧污泥结构的差异可能与它们中所含的催化活性蛋白有关。本研究从微观角度揭示了微生物群落结构、EPS组成和特性以及胞外蛋白种类和功能等信息,有助于对活性污泥特性的深入了解,为生物废水处理工艺的宏观调控提供了理论依据。
[Abstract]:A _ 2 / O process is a commonly used biological wastewater treatment process. In the wastewater biological treatment system, the pollutant removal process is essentially the metabolic process of the microorganism itself. The species, quantity and succession of community structure of microorganisms directly affect the removal of pollutants by the system. Therefore, it is necessary to study the microbial community structure in wastewater biological treatment system. DNA sequencing of anaerobic, anoxic and aerobic sludge samples from municipal wastewater treatment plants was carried out by Mi Seq high-throughput technology. The results showed that the microbes in the system were various and diverse. In aerobic and anaerobic ponds, the dominant bacteria were Proteobacteria (most dominant bacteria), Bacteroidetes and Chloroflexi.The dominant bacteria in anoxic pool were Bacteroidetes (Planctomycetes-Proteobacteria Acidobacteria and Firmicutes.) Terrimonas was the most dominant bacteria in the three kinds of sludge samples. The community structure of nitrifying bacteria in the whole system was single AOB was only Nitrosomonasaurus Nob and Nitrospira. But denitrifying bacteria diversity is high, there are a lot of aerobic denitrifying bacteria in aerobic tank, the number of autotrophic denitrifying bacteria in the whole system is very few. EPS is an important part of activated sludge floc. It can adsorb metal ions [1] and organic pollutants [2] in wastewater, play an important role in the formation and maintenance of microbial aggregates, and protect microorganisms from external adverse environmental impacts. In this study, EPSs from activated sludge of municipal wastewater treatment plant and high-salt wastewater treatment system were extracted by ultrasonic method, and the contents of protein and polysaccharide were determined. Protein was found to be the main component of EPS. The existence of proteins and polysaccharides in EPS was confirmed by IR and 3D fluorescence spectra. Humic acid was also found in EPS of high salt anaerobic tank. The results of agglomeration experiment showed that EPS of aerobic sludge was more effective than that of anaerobic sludge, and EPS of high salt anaerobic tank had little effect on sludge accumulation. As the main component of EPS, the properties of extracellular proteins largely determine the properties of EPS, and then affect the properties and functions of sludge polymers. The extracellular protein in activated sludge of sewage treatment plant was identified by bird gun method based on LC-MS / MS technique. 130108 and 114 extracellular proteins identified from anaerobic, anoxic and aerobic sludge were classified according to genetic ontology. The results showed that extracellular proteins of three kinds of sludge were involved in the biological process. The main sources and molecular functions are basically the same. Extracellular proteins are mainly derived from cell dissolution, and most of them are involved in metabolic process, cell processing process and single organism process. The main molecular functions are catalytic activity and binding activity. It is suggested that extracellular proteins have the potential functions of catalysis, degradation and binding of polyvalent cations and organic molecules. The differences between anaerobic sludge and aerobic sludge may be related to their catalytic active proteins. In this study, the composition and characteristics of microbial community structure EPS, the types and functions of extracellular proteins were revealed, which was helpful to understand the characteristics of activated sludge and to provide a theoretical basis for macro-control of biological wastewater treatment process.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

【相似文献】