好氧锥形流化床生物膜反应器启动与生物膜形成特征研究

对好氧锥形流化床膜生物反应器（A-TFBBR）的启动特征、生物膜行为、特征和结构进行了详细的探讨,并与相近启动条件下的传统柱状流化床生物膜反应器（A-CFBBR）的启动行为进行比较.结果表明,自然培养生物种源的方法与传统的以活性污泥做种源的方法相比节省了生物驯化和淘汰的时间,在短时间内就完成了生物反应器的启动（柱状床11 d,锥形床16 d）,而一般以活性污泥为种源则大都需要100～300 d的启动时间.另外,采用这种方法在A-TFBBR反应器和A-CFBBR反应器中获得的生物膜厚度分别仅为(32±1) μm 和(24±2) μm,低于大部分报道的生物膜厚度.2个生物反应器都表现出理想的COD去除能力,其中A-TFBBR反应器对COD的去除率高达95%以上,比A-CFBBR对COD的去除率平均高出15%.     

Small scale boilover and visualization of hot zone

Experimental studies of boilover were conducted in small scale rig at Universiti Teknologi PETRONAS (UTP), Malaysia and Loughborough University, United Kingdom. The study at UTP was aimed to demonstrate the ability of conducting tests at a smaller scale to simulate the boilover phenomenon. At Loughborough University, a novel laboratory scale rig was designed and built in order to obtain visual records of fuels' behaviour in a pool fire. The ultimate objective of these studies is to develop a greater understanding of boilover pertaining to fires involving the contents of storage tanks. Fuel mixtures containing light and heavy components were burnt as to study the feasibility of reproducing hot zone formation and boilover in a smaller scale and a safe environment. Boilover occurred after certain period of burning. It is found that thickness of the hot zone changed with time. It is also found that the time needed to start boilover increased when fuel thickness increased. The visualization of the fuel behaviour during the experiments was obtained to better understand the formation and growth of hot zone, the boiling of water layer and hence the boilover occurrence. Based on the data analysis and the photographs recorded from the experiments, the laboratory scale experimental rig could be used to simulate the hot zone formation mechanism and the boilover event safely and successfully. Such information are important for the understanding towards boilover phenomenon.     

雅砻江中游老里沟坡面型泥石流成因机制及危险度评价

坡面泥石流是山地分布最广,出现频率最高的灾害现象。基于野外现场调查及室内实验分析,阐述了老里沟坡面型泥石流的基本特征及形成机制,并结合泥石流动力特征参数进行了危险度评价。研究结果表明:滑坡体上坡面侵蚀沟道发育,为坡面型泥石流的形成提供了强有力的条件;降雨是诱发老里沟坡面流的主要因素;老里沟泥石流类型为高中频、小规模、粘性、暴雨型泥石流,属于中度危险泥石流沟。     

珠江三角洲新垦大气核化速率研究

计算了珠江三角洲新垦地区的大气核化速率,对核化机制及核化速率计算的影响因素进行了分析. 基于PRIDE-PRD2004观测实验期间新垦站点的气溶胶数浓度谱分布观测数据,计算出3 nm粒子的表观形成速率. 根据表观形成速率与核化速率之间的关系式,分析了1 nm粒径临界核的大气核化速率. 结果表明,新粒子事件期间3 nm粒子的表观形成速率为7.2～9.4 cm^-3·s^-1,1 nm临界核的大气核化速率为7.65×10²～1.14×10⁵ cm^-3,与前体物硫酸蒸气浓度比较一致,气态硫酸应是主要的核化前体物. 新垦地区背景气溶胶中积聚模态对碰并汇贡献较大,事件期间气溶胶数浓度变化对核化速率计算结果影响不大. 本研究获取了新垦核化速率信息,有助于进一步了解核化机制. 由于成核临界粒径的不确定性对核化速率计算结果影响很大,确定成核临界粒径对核化速率计算十分重要.     

火山泥石流研究回顾

本文简要回顾了火山泥石流的研究历史,介绍了近年来这一领域的相关研究情况.主要内容包括火山泥石流的概念,形成机制及特征研究,火山泥石流的评估,火山泥石流的数学模型及数值模拟等.在论述这一领域相关研究进展的同时,对有关研究内容进行了评述和讨论,并对今后的研究工作提出了一些建议.     

绍兴市柯桥区工业园区挥发性有机物污染特征研究

为更好地管控和治理绍兴市柯桥区工业园区的挥发性有机物(VOCs),利用柯桥区现有的两工业园区VOCs监测站点(园区1站、园区2站)2019年3月至2020年2月的监测数据分析柯桥区工业园区VOCs污染特征并进行溯源.结果表明:园区1站每月VOCs质量浓度平均值为125μg/m3,园区2站为137μg/m3,都呈现出3月...     

Effects of exogenous acylated homoserine lactones on biofilms in biofilters for gaseous toluene treatment

● Biofilm formation was enhanced by exogenous AHLs. ● EPS production and microbial adhesive strength of biofilm were promoted. ● Exogenous AHLs improved the performance of biofilters treating toluene. Biofilters are typical biofilm reactors, and they usually have poor biofilm formation resulting in limited reactor performance. Exogenous acylated homoserine lactones (AHLs) can enhance biofilm formation in many bioreactors based on quorum sensing regulation. However, their effect on biofilm in biofilters utilized for volatile organic compound (VOC) removal is unknown and needs to be investigated. In this study, the effects of the exogenous AHLs on biofilters for gaseous toluene removal were investigated. Analysis of biofilms in biofilters showed that the addition of exogenous AHLs considerably enhanced biofilm growth; the average biofilm concentration increased by 18%. Furthermore, the average biofilm coverage proportions in biofilters with and without exogenous AHLs were 17 % and 13 %, respectively, demonstrating the positive effect of exogenous AHLs on biofilm coverage. In particular, exogenous AHLs promoted the production of extracellular polymeric substances and the microbial adhesive strength of the biofilm. In addition, the exogenous AHLs showed no significant effect on the gaseous toluene removal efficiency of the biofilter. These results show that exogenous AHLs can enhance biofilm formation and can guide the application of exogenous AHLs in VOC biofilters.     

天津中心城区夏季非甲烷有机化合物组成特征及其臭氧产生潜力分析

大气中非甲烷有机化合物(NMOCs)作为臭氧产生前体物之一,其浓度与组成特征研究对于研究地面臭氧形成的机制有重要的科学意义.选择夏季时段从2009年8月6日到13日在天津中心城区气象局铁塔站位对NMOCs进行采样分析,采样频次为每日5次,采样时间从7:30am到23:00pm间隔2～3h采样1次.天津城区NMOCs的含...     

苏南五市秋冬季PM2.5化学组成特征和空间差异

于2020年9月至2021年2月在苏南五市(南京、苏州、无锡、常州和镇江)收集PM_2.5滤膜样品,分析了各样品中的水溶性无机离子和碳质组分.结果表明,苏南五市PM_2.5各组分中ρ(NO₃^-)均为最高[(9.54±10.1)～(12.1±11.3)μg·m^-3],比其它目标组分高约2倍以上.由于受更多道路扬尘和燃煤源的影响,常州市PM_2.5中Ca²⁺、Cl^-、OC和EC的浓度平均值高于其它4个城市.将所有目标组分浓度相加得到重构PM_2.5(r PM_2.5)浓度,发现各城市r PM_2.5浓度均由二次无机离子(NH₄⁺、NO₃^-和SO₄^2-,SNA)主导,占比高达(59.2%±11.1%)～(70.8%±9.72%),且r ...     

矿物超细颗粒的形成机制、结构特征及其环境行为和效应

矿物超细颗粒在自然环境中普遍存在,具有独特的环境行为和效应,对元素地球化学循环、污染物迁移转化和生态环境演变等有重要影响.矿物超细颗粒的环境行为和效应与其形成过程和结构特征密切相关.综述了物理、化学和生物过程驱动的矿物超细颗粒的形成机制,介绍了用于表征矿物超细颗粒结构特征的显微镜、光谱、质谱和同步辐射技术,分析了矿物超细颗粒在环境中的迁移转化及其与污染物的吸附、氧化还原和催化转化作用,总结了矿物超细颗粒的食物链积累、生物和生态毒性等环境效应,并对颗粒结晶路径、风险管控和微纳界面调控等重要研究方向进行了展望.超细颗粒是连接微观物质与宏观矿物晶体之间的桥梁,全面认识复杂基质中矿物颗粒的环境属性及其与污染物的微观作用机制,有助于指导矿物超细颗粒在环境污染修复中的应用,从而优化功能材料的设计,促进绿色低碳纳米技术的发展.