【作者】 窦娜莎；

【导师】 王琳；

【作者基本信息】 中国海洋大学 ， 环境工程， 2013， 博士

【摘要】 水体污染是我国面临的重要环境问题，而城市污水是我国水体的重要污染源，生物处理是解决城市污水问题最有效的方法。曝气生物滤池（BAF）作为第三代生物膜法的代表工艺之一，在城市污水二级处理中有良好的应用前景。微生物是生物处理系统中污染物去除的主要功能生物，深入研究其微生物群落结构与功能，对认识处理系统的本质、提高处理效率以及控制系统的稳定性具有重要意义。基于培养和分离纯化的传统技术已经无法满足对环境微生物群落结构研究的要求，本研究以青岛麦岛污水处理厂BAF为研究对象，综合使用多种分子生物学手段，包括核酸提取、分子克隆文库构建、16S rDNA序列同源性分析、聚合酶链式反应（PCR）、变性梯度凝胶电泳（DGGE）和荧光定量PCR技术，分析BAF系统中的微生物特性，研究了影响BAF群落结构稳定性的因素，初步探索了微生物群落结构与系统处理效能的关系。青岛市麦岛污水处理厂采用曝气生物滤池处理城市污水，对主要污染物COD、NH3-N、TP和SS的年平均去除率分别为89.1%、75.3%、83.4%和93.0%，处理效能稳定，出水水质能够达到《城镇污水处理厂污染物排放标准》（GB18918-2002）的一级B排放标准，显示了该工艺具有良好的污水处理能力。对Biostyr曝气生物滤池处理城市污水的关键影响因素的研究结果表明，当滤池进水COD和NH3-N质量浓度分别为60-260mg/L和22-65mg/L时，最佳运行参数是：水力负荷2.5-3.3m³/m².h；COD容积负荷小于3.3kg/m³.d；氨氮负荷小于0.6kg/m³.d；气水比5:1；温度15-28℃，反冲洗时间21-24h。建立了曝气生物滤池有机物去除动力学模型：C/C₀=e^{0.0118H/q-0.9423}微生物种群分布表明，沿程优势微生物依次分别为异养菌和硝化菌，微生物组成和活性的不同导致BAF各段对不同污染物的去除能力不同，BAF降解COD的最佳填料层高度为0-150cm，硝化NH3-N的最佳填料层高度为100-350cm，0-100cm段的填料层对SS的去除率贡献最大。曝气生物滤池生物膜的细菌多样性结果表明BAF生物膜中细菌多样性十分丰富，按照优势类群依次β-proteobacterium类群（占38.6%），γ-proteobacterium类群（占18.2%），Bacteroidetes类群（占13.6%），-proteobacterium类群（占9.1%），-proteobacterium类群、Nitrospirae类群（各占4.5%）和Firmicutes类群（占2.3%）。BAF中主要的有机物去除功能菌是食酸假单胞菌、球衣菌、黄单胞菌和黄杆菌；亚硝化细菌为亚硝化单胞菌，硝化细菌为硝化螺菌；主要的反硝化细菌为生丝微菌和丛毛单胞菌。对气水比、温度和反冲洗对BAF群落结构的影响分析结果表明，BAF具有良好的生态稳定性，在气水比为5:1生境下滤池内流态稳定，生物膜结构合理，出水水质最佳；低温（T＜15℃）会影响到BAF菌群多样性，使滤池内优势菌群变得单一，但是这种单一的优势菌群能够维持BAF的稳定运行；聚类分析表明反冲洗作为影响因子极大地影响着BAF的群落结构，因此，控制好滤池的反冲洗强度和频率是BAF高效运行的关键环节。除趋势典范对应分析（DCCA）结果表明，气水比、反冲洗和水温是影响BAF群落结构的主要的环境因子，COD去除率、氨氮去除率、总磷去除率和硝态氮浓度对BAF内物种的影响显著（P<0.001），其中COD去除率与群落结构的相关性较大，为-0.7947（P<0.001），而亚硝态氮浓度与排序轴没有达到统计学上的相关性，与BAF中微生物群落结构演替没有明显关系。更多还原

【Abstract】 Water pollution is one of the most serious environmental problems in China, andmunicipal wastewater is a major pollution source to water bodies in our country.Biological treatment process is the most efficiently used method to treat municipalwastewater. Biological aerated filter （BAF） as one of the representative process ofthird-generation biofilm process has a great application potential in the secondarytreatment of municipal wastewater. In the biological treatment systems,microorganisms are key organisms in pollutant removal. Therefore, a better study ofthe bacterial community structure and function in the treatment system can help toelucidate the pollutant removal mechanism of BAF and enhance the treatmentperformance stability. Traditional technologies for environmental microbiologyresearches mainly based on culture and separation could not satisfy nowadaysenvironmental microbiology research. In this paper, the BAF used in Qingdao Maidaosewage treatment plant is studied, microorganism characteristic in full-scale BAF isinvestigated using molecular techniques, including nucleic acids extraction, clonelibrary construction,16S rDNA sequence homology analysis, polymerase chainreaction （PCR）, denaturing gradient gel electrophoresis （DGGE）, and quantitativereal-time PCR techniques. The factors affecting the microbial community structureare identified. The relationship between microbial community dynamics and systemfunction is analyzed.Qingdao Maidao wastewater treatment plant uses Biostyr BAF for municipalwastewater treatment, major pollutants COD, NH3-N, TP and SS removal efficiencyof the annual average are89.1%,75.3%,83.4%and93.0%, respectively. Processingperformance and stability, the effluent indexes are better than the Ⅰ-B criteriaspecified in discharge standard of pollution for municipal wastewater treatment plant（GB18198-2002）, shows that the process has a good capacity of sewage treatment.The results of the affecting factors of BAF show that when COD and NH3-N ininfluent are between60-260mg/L and22-65mg/L, respectively. The optimumhydraulic loading is between2.5-3.3m³/m².h. The optimum COD loading is below 3.3kg/m³.d. The optimum ammonia nitrogen loading is below0.6kg/m³.d；Theoptimum gas to liquid ratio is5:1. The optimum temperature is between15-28℃. Theoptimum backwash time is21-24h. The organic removal kinetic model of BAF isC/C₀=e^{0.0118H/q-0.9423}The difference of microbial composition and activity can cause diverse ability ofdifferent pollutants removed. Results of microbial population distribution show thatthe dominant microbes are heterotrophic bacteria and denitrifying bacteria along theheight, respectively. For BAF, the best height of COD degradation is0-150cm,nitrifying NH3-N best height is100-350cm, and0-100cm segment of media take thelargest contribution to the removal rate of SS.BAF biofilm bacterial diversity results show that the bacterial diversity in theBAF is very rich, dominant microorganisms is β-proteobacterium groups, γ-proteobacterium groups, Bacteroidetes group,-proteobacterium groups,-proteobacterium groups, Nitrospirae and Firmicutes in the order. In the Biostyr BAF,Pseudomonas, Sphaerotilus, Xanthomonas and Flavobacterium are dominantmicroorganisms to remove organic pollutants, Nitrosomonas is advantage nitrosationbacteria, Nitrospira is advantage nitrification bacteria, Hyphomicrobium andComamonas are advantage denitrifying bacteria.The influence of gas water ratio, temperature and backwash on BAF communitystructure are analyses, the results show that BAF has good ecological stability. Whenthe gas water ratio is5:1, the filter flow of BAF is in stability, biological membranestructure is reasonable and the effluent is the best. Low temperature （T＜15℃） willaffect the bacterial diversity of BAF, make advantage bacterium group within thefilter becomes single, but this kind of single advantage bacterium group can maintainthe stable operation of the BAF. Low temperature will affect the bacterial diversity ofBAF, make advantage bacterium group within the filter becomes single, but this kindof single advantage bacterium group can maintain the stable operation of the BAF.Clustering analysis indicates that the backwash as influence factor greatly affects thecommunity structure of BAF. Therefore, a good control for the intensity andfrequency of backwash is a key link in efficient operation of BAF.The DCCA analysis results show that, the gas/water ratio, backwashing and temperature are the main effect factors of BAF community structure. The effects ofCOD, ammonia nitrogen and total phosphorus removal rate, and the concentration ofnitrate nitrogen on BAF species is significantly （P<0.001）, in which the correlationbetween COD removal rate and community structure is the largest, the value is-0.7947（P<0.001）. However, the nitrite nitrogen concentration did not reachstatistical correlation with the axis, so there is no obvious relationship betweenmicrobial community structure succession in BAF and the nitrite nitrogenconcentration.更多还原