【作者】 汤迎；

【导师】 李小明；

【作者基本信息】 湖南大学 ， 环境科学与工程， 2014， 博士

【摘要】 近年来,药物及个人护理品(Pharmaceuticals and Personal Care Products, PPCPs)作为一类新兴的环境污染物,在多种环境介质中被频繁检出,以及对人体健康及生态环境具有一定的风险,引起了人们的广泛关注。我国对新兴污染物的研究正在逐渐兴起,现阶段缺乏PPCPs类污染物的排放标准及质量控制标准。污水处理厂是PPCPs类污染物进入环境的主要点源,同时也是去除这类污染物的重要途径。我国现有关于PPCPs类污染物的研究,大多集中在污水处理厂内PPCPs的赋存调研,物质对象上多关注于抗生素类PPCPs,而具体到实验室机理解析甚少。本研究利用GC/MS和HPLC等高效分析检测手段,以多类别PPCPs为研究对象,揭示了PPCPs在城市污水处理厂中的存在特征与环境风险,并深入探究活性污泥对典型PPCPs的去除规律与机理。通过为期三年的不间断跟踪监测,摸清了11种目标PPCPs在广东地区三家污水处理厂内的存在特征与环境风险。结果表明：目标PPCPs在城市污水处理厂内的检出率很高,浓度水平低于国外报道的浓度水平,与国内其他报道相近。生活污水是PPCPs的主要污染源。PPCPs的进水浓度主要与PPCPs的人为使用量及旱雨季相关。而其他各工艺段及出水中PPCPs的浓度变化一定程度上受限于进水浓度,而决定因素是各污水处理工艺段的去除效果。目标PPCPs的最大浓度值多出现在1月,最小浓度值多出现在7月。生物处理工艺对目标PPCPs的去除起主要的作用,厌氧池和好氧池是对城市污水处理厂内PPCPs总去除率贡献最大的污水处理单元,缺氧池内目标PPCPs的去除率多出现负值。风险评价表明,城市污水处理厂STP1出水中双氯芬酸对水生生物有高风险,水杨酸和甲芬那酸对水生生物有中等风险；城市污水处理厂STP3出水中氯贝酸和双氯芬酸对水生生物有中等风险；三氯生在三家污水处理厂中的出水浓度均对水生生物有高风险。在活性污泥去除典型PPCPs的烧杯实验中,活性污泥对罗红霉素有显著的吸附作用,对苯扎贝特及萘普生有较强的生物降解作用。废水中的高浓度药品会对活性污泥系统产生急性毒性,罗红霉素致活性污泥急性毒性浓度值高于布洛芬。活性污泥降解萘普生和苯扎贝特的过程可以用伪一级动力学来进行描述,吸附过程可以用伪二级动力学方程描述。降解及吸附速率常数均与底物初始浓度存在一定的负线性相关性,活性污泥吸附目标污染物是目标物的疏水性及目标物与活性污泥间的静电反应共同起作用的结果,该吸附过程适用于Freundlich吸附等温线。活性污泥中萘普生解吸作用不明显,因此,剩余污泥的处理与处置过程中,萘普生不易造成环境的二次污染。利用454高通量测序技术,了解了活性污泥系统中微生物群落结构与系统除污(目标PPCPs类污染物萘普生和常规污染物C/N/P)性能的耦合关系,降解萘普生的优势菌群主要集中在变形菌门的p变形菌纲。不同pH进水条件下,驯化后系统中形成的微生物菌落结构存在很大差异。酸性条件下形成的微生物群落能够更好地去除萘普生,但是系统的稳定性差,中性条件下驯化后系统中微生物的多样性程度较高,群落结构复杂,系统的抵抗力、稳定性较强,对于高浓度单一含萘普生的废水呈现较好的去除效果。更多还原

【Abstract】 In recent years, pharmaceuticals and personal care products (PPCPs) as a kind of emerging environmental pollutants, have attracted widespread concerns due to the frequent detection in various environmental media and the potential risk to human health and ecological environment. The study of emerging contaminants in our country is gradually rise. At this stage, the pollutant emissions standards and quality control standards about this kind of pollutants are absent. Sewage treatment plants identified as the main point source of PPCPs into the environment, is also an important way for removing this type of pollutants. Most studies on the occurrence of PPCPs in our country have been evaluated by investigating the concentration of PPCPs in the sewage treatment plants, and few specific to the laboratory mechanism analysis. The object of these studies is mostly for antibiotic.In this reseach, using GC/MS and HPLC detection means, we study the occurrence and environmental risks of PPCPs belonging to different therapeutic classes in full-scale sewage treatment plants, and the removal mechanism of to the typical PPCPs by activated sludge in the laboratory.The concentrations of eleven kinds of target PPCPs in the three sewage treatment plants in Guangdong were monitored over the course of three years, to gain an insight into the occurrence and environmental risks. The results showed that the detection rates of the target PPCPs in the three sewage treatment plants were very high, and the concentration levels were lower than those in the other countries and similar with the other domestic reports. The main source of PPCPs in the water environment was identified as domestic wastewater. The influent concentrations of PPCPs were mainly associated with the human use and the rainy season. The concentrations of PPCPs in sewage treatment units and effluent were restricted to feed concentrations and determined by the removal effects of the sewage treatment units. The maximum concentrations mainly occured in January, while the minimum in July. Biological treatment process played a main role in the total removal efficiencies. Anaerobic tank and aerobic tank were beneficial to remove of PPCPs, and anoxic tank often appeared negative removal rates. Risk assessment showed that diclofenac could pose a high risk to aquatic organisms in the effluent of sewage treatment plant STP1, and salicylic acid and mefenamic acid could pose a medium risk to aquatic organisms. In sewage treatment plant STP3, clofibrate and diclofenac could pose a medium risk to aquatic organisms. Triclosan could pose a high risk to aquatic organisms in the three sewage treatment plants.This study investigated the degradation characteristics of three acidic pharmaceuticals (naproxen, benzafibrate and ibuprofen) and roxithromycin in the presence of activated sludge under aerobic and anoxic conditions. Experimental results indicated that roxithromycin was significantly adsorbed by activated sludge, and the effective biodegradation of benzafibrate and naproxen was observed both under aerobic and anoxic conditions. The concentration of roxithromycin leading to acute toxicity on activated sludge was higher than that of ibuprofen. The degradation of naproxen and benzafibrate could be described by pseudo first-order kinetic model, while the adsorption data could be well interpreted by pseudo second-order kinetic model. The spiked concentrations of the two-target compounds were negatively correlated with degradation and adsorption rate constant. The adsorption of pharmaceuticals by activated sludge was rapid, and the relative adsorbabilties of the two-target compounds based on their log Kow and pKa values. The adsorption process of naproxen in activated sludge was suitable for the Freundlich adsorption isotherm. Desorption effect of naproxen was not obvious, therefore naproxen was not easy to cause secondary pollution to the environment in the excess sludge treatment and disposal process.Using454high-throughput sequencing technology, we realized the coupling relationship between the microbial community structure and the capacity of decontamination in activated sludge system. The bacterium group achieved advantage degradation of naproxen were mainly classified as Betaproteobacteria. There are considerable differences of the microbial community structure between different pH conditions in the domestication system. Under the acid condition, the system could better remove naproxen, but poor stability. The high levels of naproxen removal from the high concentration wastewater only containing naproxen was achieved by the domestication system under neutral condition, and the system had complexity and diversity of microbial ecology.更多还原