【作者】 张斌；

【导师】 季民；

【作者基本信息】 天津大学 ， 环境工程， 2010， 博士

【摘要】 本研究将传统污水污泥监测手段与聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)、实时定量PCR和荧光原位杂交(FISH)等分子生物学技术相结合,重点以膜生物反应器(MBR)和颗粒污泥序批式反应器(GSBR)内污泥微生物为主要研究对象,系统地对其污染物去除特征、整体微生物群落结构的演变规律、氨氧化菌群的演变规律与定量分析及颗粒污泥中几种重要功能菌群空间分布规律等方面进行了较为深入的研究,具体成果如下:1)在MBR启动初期,污泥中微生物群落结构变化较大;试验过程中,Pseudomonas和Aeromonas hydrophila等种群保持着较为稳定的优势地位,接种污泥中的Bacillus sp等逐渐消亡,而Enterococcus faecalis、Comamonas sp、Fusobacterium sp等次级种群得到强化。在运行后期演变为优势地位的菌群(如Comamonas sp)加剧了膜污染物的产生和积累;膜污染物中EPS浓度约是反应器污泥中的4倍,主要由分子量在12000以上的大分子物质组成,多糖和蛋白质类物质是主要的膜污染物;2) MBR运行期间氨氧化菌(AOB)群落结构的演替过程较为缓慢, Comamonas sp、Uncultured Nitrosomonas sp、Uncultured Nitrosospira sp和Uncultured beta Proteobacterium clone nsc162等种群一直保持着较为稳定的优势地位;实时定量PCR结果表明,氨氧化菌含量在经过驯化期后显著增长。但污泥的氨氧化活性随着污泥浓度的增长而降低;3)GSBR中污泥沉降性能的改善要先于颗粒污泥的形成,而污泥粒径的演变对其沉降性能影响较小。在颗粒形成初期丝状菌和杆状菌起到了搭建骨架和支撑结构的作用,而在后期大粒径污泥中主要以球状菌的填充和聚集为主。颗粒污泥形成过程中微生物群落结构演变较为平缓;颗粒污泥中绝大多数种群分布于Proteobacteria纲,其中聚磷菌(PAO)所占优势地位较明显,硝化螺旋菌属和具有好氧反硝化功能的Thauera逐渐演变为优势种群,拟杆菌纲在前期占有优势地位,而在后期逐渐消亡;4)GSBR中污泥接种驯化期,氨氧化菌群结构的变化较为剧烈,种群多样性迅速下降;但随着污泥沉降的改善而趋于稳定。在颗粒污泥形成过程中大多数亚硝化单胞菌属被保留在系统内,而亚硝化螺菌属逐渐被淘汰。在经历了运行初期的淘洗后,AOB含量随着污泥浓度的提高而逐渐增长;但污泥的氨氧化活性随着污泥浓度的增长而降低;5)在粒径小于0.6mm的颗粒污泥中,氨氧化菌、亚硝酸盐氧化菌(NOB)和聚磷菌较均匀地分布于整个污泥空间;而在粒径大于0.9mm的颗粒污泥中AOB和NOB、PAO通过竞争性生长分别存在于颗粒的外层和次外层,而其核心区域为反硝化菌的生长创造了适宜的环境。更多还原

【Abstract】 In this study, membrane bioreactor(MBR) and granular sequencing batch reactor(GSBR) were thoroughly investigated in terms of pollutants removal performance, the succession procedure of microbial communities, population dynamics and quantification of ammonia-oxidizing bacteria(AOB) and spatial distribution characteristics of functionally important microorganisms. A polyphasic approach incorporating the traditional monitoring methods for wastewater and sludge, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), Real-time quantitative PCR and fluorescence in situ hybridization (FISH) was applied to investigate the microbial community structures in the two systems.The main research results were summarized as follows:1) The noticeable change was taken place in microbial structure during the initial operation of MBR. In the process of experiment, the populations such as Pseudomonas and Aeromonas hydrophila were found to be stably the predominant species, the primary communities such as Bacillus sp died out, and the secondary microbial communities such as Enterococcus faecalis、Comamonas sp and Fusobacterium sp increased. The preponderant bacteria (such as Comamonas sp) that increased during the later stage of operation intensified the producing and accumulation of membrane pollutants. The content of EPS in membrane fouling was about 4 times as much as that in active biomass, which were mainly maken up of macromolecule substances(over 12000D) and polysaccharide and protein were the most important pollutant.2) In the process of MBR, variation of AOB community was slower. Comamonas sp, Uncultured Nitrosomonas sp, Uncultured Nitrosospira sp and Uncultured beta Proteobacterium clone nsc162 were dominated species in AOB population. The amount of AOB increased significantly after domestication. Nevertheless, ammonia-oxidizing activity of biomass decreased along with the increase of MLSS.3) In GSBR, the improvement of sludge sedimentation performance occurred earlier than the formation of granular sludge and was not effect by the variance of particle size of sludge. Rod-shaped bacteria and filamentous bacteria served as a means of building frames and supporting structures in the primary period of granulation, as well as the large granules were packed with spherical bacteria. During the sludge granulation, microbial community structures changed gently. In granular sludge, most species were belonging to Proteobacteria and the polyphosphate-accumulating organisms (PAO) were found to be the dominant genera. The initial predominant communities such as Bacteroidetes died out gradually, and the secondary microbial communities such as Nitrosospira and Thauera became dominant groups.4) In GSBR, the variation of AOB was remarkable in the period of sludge inoculation, and diversity of population was reduced rapidly. Subsequently, AOB community structure tended to be stable along with the improvement of sludge sedimentation performance. In seed sludge, most of Nitrosomonas sp. was remained in GSBR; however, all of Nitrosospira sp. was gradually eliminated during sludge granulation. The amount of AOB increased gradually after undergoing the early stage of wash-out. However, ammonia-oxidizing activity of biomass decreased along with the increase of MLSS.5) In the granular sludge that particle diameter was less than 0.6mm, AOB, nitrite oxidizing bacteria (NOB) and PAO distributed evenly in the whole of granular space. In the granular sludge that particle diameter was over 0.9mm; AOB was mainly located in the surface area of the granule, while NOB and PAO were in the subsurface layer. The core areas of granular provided suitable environment for the growth of denitrifying bacteria.更多还原