摘 要

好氧颗粒污泥具有紧密的结构以及较高的生物量和生物活性，因此具有沉降性能好 、耐冲击能力强 、能承受较高有机负荷等优点，所以其在污水同步脱氮除磷、高浓度有机废水和难降解废水处理，以及重金属吸附等方面具有良好的应用潜力。但是好氧颗粒污泥技术存在颗粒污泥培养周期较长，系统运行后期颗粒稳定性差的问题，制约了该技术的推广应用。细菌作为颗粒污泥的重要组成部分，对于颗粒污泥的形成、稳定性以及功能的发挥方面起着决定性作用。了解颗粒污泥形成过程中菌群结构的变化，对于认识颗粒污泥微生物学机理，了解菌群结构与颗粒污泥稳定性和功能的关系具有重要意义。但目前尚缺乏颗粒污泥形成过程中菌群结构变化的信息。

本研究以SBR反应器的接种絮状污泥（AS组）和培养150天后形成的颗粒污泥样品（GS组）为实验材料，利用PCR和高通量测序技术对细菌的16S rDNA进行扩增和测序，根据测序结果得出样品各细菌的相对丰度，研究了颗粒污泥形成前后的菌群结构变化，并对优势菌的功能与颗粒污泥特性的关系进行了分析。主要研究内容及结果如下：

（1）在门水平上，AS和GS组中，Proteobacteria门均占绝对优势，分别占70.0%和74.3%。在纲水平上，AS组占绝对优势的是Betaproteobacteria纲（占47.9%），GS组中占绝对优势的是Gammaproteobacteria纲（占56.4%）。在目水平上，AS组中优势菌为Rhodocyclales目（占23.9%）；GS组中优势菌为HOC36(占54.5%)，其次是Nitrospirales目（占11.8%）。在科水平上，AS组的优势菌为Rhodocyclaceae科（23.9%）；GS组的优势菌为Nitrospiraceae科（占11.8%）。在属水平上，AS组的优势菌为Dechloromonas（占13.3%），其次是Candidatus Accumulibacter（占4.9%）；GS组的优势菌为Nitrospira（占11.8%），其次是Candidatus Accumulibacter（占5.1%）。

（2）分析了颗粒污泥形成过程中主要的功能细菌，其中参与脱氮过程的细菌有Nitrospira，Dechloromonas以及Candidatus Accumulibacter；参与除磷的细菌有Candidatus Accumulibacter和Limnohabitans；丝状菌为Candidatus Microthrix；可产生EPS的细菌为Zoogloea；Dechloromonas和Sulfuritalea分别能还原（高）氯酸盐和氧化还原性硫化物；而Rubrivivax、Dokdonella和Nannocystis所具有的功能尚不明确。由于这些细菌在颗粒污泥形成前后所占比例发生了改变，使最终形成的成熟好氧颗粒污泥具有良好的脱氮除磷能力以及远高于普通污泥的SVI（污泥沉降指数）。

关键词：好氧颗粒污泥；细菌群落结构；优势菌；脱氮除磷

Abstract

The aerobic granular sludge has the advantages of tight structure, good settling performance, strong impact resistance, high organic load, high biological activity and high biological activity. So it has good application potential in the field of wastewater treatment, such as simultaneous nitrogen and phosphorus removal, high concentration organic wastewater and refractory wastewater treatment, and heavy metal adsorption. However, aerobic granular sludge technology has the problem of having a long incubation period, and the poor stability of particles in the later period of the system, which restricts the popularization and application of this technology. As an important part of granular sludge, bacteria play a decisive role in the formation, stability and function of granular sludge. Understanding the changes of bacterial community structure during the formation of granular sludge has important significance for understanding the mechanism of granular sludge microbiology, the relationship between the structure of the bacteria and the stability and function of the granular sludge. But there is still lack of information about the structure of bacteria in the formation of granular sludge.

In this study, flocculent sludge (AS group) seeded in SBR (Sequencing Batch Reactor) and granular sludge samples (GS group) after training 150 days as experimental materials. PCR and high throughput sequencing technology were used to amplifing and sequencing 16S rDNA of bacterial. According to the relative abundance of each bacterium obtained from the sequencing results, the structure of the bacteria before and after the formation of granular sludge was studied. And the relationship between the function of dominant bacteria and the characteristics of granular sludge was analyzed. The main research contents and results are as follows:

(1) At the phylum level, in AS and GS group, Proteobacteria phylum is the dominant, accounting for 70% and 74.3% respectively. At the class level, Betaproteobacteria class (47.9%) has the absolute advantage in the AS group. Gammaproteobacteria class (56.4%) has the absolute advantage in the GS group. At the order level, the dominant bacteria in the AS group is Rhodocyclales order (23.9%), and the dominant bacteria in the GS group is HOC36 order (54.5%), followed by Nitrospirales order (11.8%). At the family level, the dominant bacteria in the AS group is Rhodocyclaceae family (23.9%), and the dominant bacteria in the GS group is Nitrospiraceae family (11.8%). At the genus level, the dominant bacteria in the AS group is Dechloromonas (13.3%), followed by Accumulibacter Candidatus (4.9%); the dominant bacteria in the GS group is Nitrospira (11.8%), followed by Accumulibacter Candidatus (5.1%).

(2) Analysis of the main functional bacteria in the formation of granular sludge, the bacteria involved in the process of nitrogen removal were Nitrospira, Dechloromonas and Accumulibacter Candidatus; the bacteria involved in phosphorus removal were Accumulibacter Candidatus and Limnohabitans; filamentous bacteria is Candidatus Microthrix; the bacteria that can produce EPS is Zoogloea; Dechloromonas and Sulfuritalea can restore (per) chlorate and oxidate educed sulfide; but the function of Rubrivivax, Dokdonella and Nannocystis is not clear. However, it is because of the changes of community structure during the granular sludge formation period, the ultimately mature aerobic granular sludge has a good nitrogen and phosphorus removal ability and has much higher SVI (sludge volume index) than that of conventional activated sludge.

Keywords: Aerobic granular sludge; bacterial community structure; dominant bacteria; nitrogen and phosphorus removal

目录

摘要 I

Abstract III

第1章 绪论 1

1.1好氧颗粒污泥 1

1.1.1好氧颗粒污泥研究进展 2

1.1.2好氧颗粒污泥形成机理 2

1.2菌群结构研究技术 3

1.3研究意义及主要内容 4

1.3.1研究意义与目的 4

1.3.2主要研究内容 5

第2章 材料与方法 6