【作者】 刘易；

【导师】 赵建夫； 夏四清；

【作者基本信息】 同济大学 ， 环境科学， 2007， 博士

【摘要】 烷基酚类物质（APs）作为内分泌干扰物（EDCs）中的一种,已经在环境领域引起了普遍关注,烷基酚类物质中毒性最大、污染范围最为广的为壬基酚（NP）和辛基酚（OP）。本文首先以上海安亭污水处理厂的进水为代表,研究了上海典型生活污水中EDCs的种类,并分析了化学生物絮凝工艺（CBF）对内分泌干扰物的去除效果。在进水中共发现8种内分泌干扰物,主要包括以4-t-OP（简称OP）为代表的烷基酚类和邻苯二甲酸酯类。CBF工艺对所有检测到的内分泌干扰物均有一定去除效果,烷基酚类较高,去除率在60%-99%之间;对于酯类物质的去除率略低,约为30%-34%。CBF工艺反应器中EDCs的去除过程可能主要包括生物吸附与化学絮凝作用。根据以上研究结果,选择OP作为研究的目标污染物。考虑到现阶段我国城市污水处理主要使用活性污泥工艺,而城市污水处理厂是EDCs进入环境的一个重要途径,因此,本文主要研究了活性污泥对OP的去除特性,包括活性污泥对OP的吸附和降解特性以及好氧、缺氧、好氧-缺氧SBR活性污泥小试工艺对OP的去除效果。结果表明,活性污泥对OP既有吸附作用也有降解作用。活性污泥对OP吸附包括快速吸附与慢速吸附两个阶段,吸附过程符合一级动力学方程。随着污泥浓度的增加,吸附速率减小,吸附平衡时间增加,达到吸附平衡时,分配系数K_p与污泥浓度之间的关系可以用方程K_p=a（SC）^b描述。低温有利于吸附,当pH值在5.0-9.0范围时,pH值对吸附的影响不大。活性污泥对OP吸附量的大小与活性污泥粒径成负相关性,因此活性污泥对OP的吸附可能以表面吸附为主。活性污泥在好氧环境对OP的降解性能要优于厌氧环境。随着OP初始浓度的增加,降解速率有所降低;好氧条件下活性污泥对OP降解的最佳pH值为8.0,厌氧条件下为7.0;酵母膏的添加对OP降解的促进作用显著,在好氧条件下,苯酚也明显的促进了OP的降解。活性污泥以OP为主要碳源进行培养后,优势菌种主要属于γ-变形菌门。此外,在好氧条件下培养的活性污泥中,也发现相当的优势菌种属于厚壁菌门。通过小试装置模拟城市污水条件下活性污泥工艺对OP的去除效果。试验发现活性污泥工艺对OP的去除效果较好,OP的添加并未明显影响反应器对其他污染物的去除效率。活性污泥系统中都存在着钟虫等多种原生动物,出水水质较好。碳/氮比的减小有利于活性污泥对OP的去除;停留时间的延长,增强了OP的去除效果;在OP进水浓度为50～150μg/L的范围内,随着浓度的增加容积负荷也随之增加。在本文研究的三种活性污泥法反应器中,缺氧-好氧SBR反应器对OP的去除效果最佳,当进水浓度为150μg/L时,最高容积负荷可达到85.1μgL^-1d^-1,其次为好氧活性污泥反应器,最后为缺氧活性污泥反应器。对三种活性污泥系统进行微生物群落结构分析,发现均以属于β-变形菌门的优势菌种比例最高,这与普通活性污泥微生物群落结构一致,说明OP的生物毒性没有使活性污泥中的主要优势菌种产生显著的改变。此外,好氧活性污泥反应器中还发现了属于γ-变形菌门和δ-变形菌门的优势菌种,而缺氧和SBR反应器中还发现了属于γ-变形菌门以及厚壁菌门的优势菌种。近年来好氧颗粒污泥处理系统得到大力开发。与活性污泥相比,颗粒污泥具有独特的结构特征,可为各种代谢类型的微生物提供适合的生长环境,因此本文也研究了颗粒污泥对OP的降解性能,得出的主要降解规律与活性污泥相类似。颗粒污泥在以OP为主要碳源培养后,生物多样性比接种污泥明显减小。好氧培养后优势菌种主要属于γ-变形菌门;厌氧培养后优势菌种主要属于厚壁菌门。本文通过分离纯化,共得到两株OP降解菌。通过鉴定,这两株菌均属于γ-变形菌门,其中OP-1属于假单胞菌属,OP-2属于成团泛菌属。迄今为止,属于成团泛菌属的烷基酚降解菌尚未见报道。降解菌OP-1对OP降解的最佳pH值为7.0,OP-2为8.0;并且葡萄糖的添加有利于菌种OP-1对OP的降解。更多还原

【Abstract】 In resent years, alkylphenols（APs） as an important class of endocrine disrupting chemicals （EDCs） has been paid intensive attention to in environmental science research. Nonylphenol（NP） and octylphenol（OP） are most toxic compounds among the APs, and have been widely detected in the environment.At first, we took the influent of Anting Wastewater Treatment Plant as an example to study the kinds of EDCs in the influent of typical municipal wastewater in Shanghai, and investigated the removal performance of EDCs in chem-bioflocculation （CBF） treatment process. We have detected 8 kinds of EDCs, mainly including 4-t-OP（OP for short） and phthalates （PAEs）. The results showed that all EDCs have been detected could partly be removed by CBF treatment process. The removal rate of the alkylphenols ranged from 60% to 99%, while the removal rate of the esters was 30%-34%. It shows that biosorption and flocculation play the central role of the removal of EDCs in CBF treatment process.For OP has been detected in the influent, we decided to take it as our target compound. Recently, activated-sludge process is the most popular process for the municipal wastewater treatments which are important sources of EDCs in the environment. So we mainly researched the removal capability of OP in activated sludge process. There are absorption and biodegradation characters for OP in different process, and the removal performance by aerobic、anoxic and anoxic-aerobic SBR reactors were studied.The process of OP absorption by activated sludge could be divided into two steps, one was quick absorption period, and the other was slow absorption period. The quick absorption period fits the first-order kinetics. As the concentration of the sludge increase, the absorption speed became slower, and the equilibrium time went longer The relationship between distribution coefficient （K_p） and the concentration of the sludge could be described by the equation K_p=a（SC）^b. Low temperature benefited the absorption function. When the pH value belonged to 5.0 to 9.0, the pH value could barely affect adsorption. K_p has negative relativity with the diameter of activated sludge, so we think it probably turn out to be a surface adsorption.In comparison, OP degradation rate in activated sludge under aerobic condition was higher than that under anaerobic condition. The degradation rate decreased with the increase of the initial OP concentration. The optimal pH values for OP degradation were 8.0 and 7.0 under aerobic and anaerobic condition, respectively. Addition of yeast extract enhanced the OP degradation, and under aerobic condition, phenol could also enhance the degradation. After incubated with OP as a main carbon source, the major species of activated sludge were identified asγ-proteobacteria. Furthermore, we also found major species identified as firmicutes under aerobic condition.We simulated OP removal performance in municipal wastewater by activated-sludge process through reactors in our lab. The result showed that the activated-sludge process could remove OP efficiently, and increasing of OP concentration did not affect the removal of other pollutants. There were many protozoa in activated sludge systems, such as vorticella and so on. The removal rate of OP went higher with the C/N decreased. And the longer the residence time was, the higher the removal rate became. When OP concentration was 50-150μg/L in the influent, the volume load became higher with OP concentration increased. When OP concentration was 150μg/L in the influent, the volume load of the anoxic-aerobic SBR reactor could achieve 85.1μgL^-1d^-1, which was the most efficient reactor on OP removal among the three kinds of reactors studied in this paper, second was the aerobic reactor and the third was the anoxic reactor. We investigated microbial community in the three different activated sludge systems, and found that most major species separated identified asβ-proteobacteria which was the same as traditional activated sludge system. This indicated the toxicity of OP did not obversly change the main major species in the sludge. Besides, we also found major species identified asγ- proteobacteria andδ- proteobacteria in aerobic reactor andγ- proteobacteria and firmicutes in anoxic reactor.In recent years, aerobic granular sludge process has been developed quickly. Compared to traditional activated sludge, granular sludge has special particular granular structures which could improve the environment for varieties of bacterium. So we studied the degradation of OP in granular sludge process, too, and got the same result as activated sludge. After incubated with OP as a main carbon source, the biological diversity decreased obviously. The major species found in granular sludge were identified asγ-proteobacteria under aerobic condition, while the major species were identified as firmicutes under anaerobic conditionAfter separation and purification, two different strains were obtained for OP degradation. Both of them were identified asγ-proteobacteria. Strain OP-1 belong to Pseudomonas, and strain OP-2 belong to pantoea agglomeran which hasn’t been reported as OP degradation bacteria before. The optimal pH value for strain OP-1 degrading OP was 7.0 and was 8.0 for strain OP-2. Strain OP-1 degraded OP more efficiently by adding glucose as a carbon source.更多还原