膜生物反应器的工艺应用现状综述

膜生物反应器(MBR)是一种膜分离单元与生物处理单元相结合的新型污水处理技术,在污水处理与回用、垃圾渗滤液处理方面有良好的应用前景.本文阐述了膜生物处理法(MBR)的处理机理;综述MBR的工艺应用现状及其工业应用;最后就MBR工艺的发展做展望。     

生物立方膜

脂质立方液晶在药物载体方面有着较为广泛的应用.然而在生物体内,有一种与之类似的结构,称为立方膜.具体而言,立方膜就是指含有脂蛋白的三维周期性脂质双分子单层、双层或多层的纳米曲面结构.亚细胞器中的这种生物立方膜结构可能也能作为药物载体,同时有抗氧化、紫外滤光等潜在作用.本文将主要介绍立方膜的研究进展、形成机理,以及在自然界中的存在情况,及其功能和潜在的应用价值.     

家用空气净化器HEPA滤网中呼吸道病原物种类分析

采用微流体芯片核酸检测技术对不同使用时间、场所家用空气净化器HEPA滤网中呼吸道病原物种类进行分析。结果表明,在61个HEPA滤网样本中,共有21个样本检出8种呼吸道病原物。不同使用时间、场所HEPA滤网病原物检出率存在一定差异,滤网实际使用时间、场所是病原物检出率的主要影响因素,建议使用者定期对HEPA滤网进行更换或清洁保养。     

细菌生物被膜与食品生物危害

食源性病原菌生物被膜是威胁食品安全的一个重大隐患。生物被膜一旦在食品加工过程中形成,易引起相当严重的交叉污染和加工后污染,产生极大危害,从而导致一系列严重的健康问题。本文就食源性病原菌生物被膜的分布、形成机制以及防治措施进行了综述。     

肺炎克雷伯菌生物被膜豚鼠肺感染模型建立的实验研究

目的采用吸入法建立肺炎克雷伯菌生物被膜（BF）肺感染模型,探讨肺内肺炎克雷伯菌BF的发生发展变化及其BF菌周围炎性细胞的变化。方法40只豚鼠随机分为两组：A组和B组动物分别通过喷雾器接种灭菌生理盐水及肺炎克雷伯菌菌悬液,取材日进行活菌计数、光学及电子显微镜检查。结果肺炎克雷伯菌BF在肺内以特异的肉芽肿结节的形式存在,有体内炎性细胞的参与。扫描电镜可见结节内有多糖蛋白复合物包绕的细菌,菌体之间相互以粘液丝相连。结论吸入法BF肺感染模型方法简单、重复性好,可用于BF菌相关肺感染的研究。     

白色念珠菌生物被膜研究进展

难治性真菌感染的临床分析发现,病灶感染病原常以生物被膜的形态存在。生物被膜的形成可帮助真菌躲避宿主细胞免疫系统清除和药物的攻击,所造成的持续性感染严重威胁人类健康,因此,认识研究真菌生物被膜及其耐药机理对于防治临床真菌感染有着重大意义。白色念珠菌是一种临床感染常见的条件性致病菌,也是目前真菌生物被膜研究的主要研究模型。白色念珠菌生物被膜主要由多糖、蛋白质和DNA构成,其形成由微生物间的群体感应调控,并受到环境中营养成分及其附着物表面性质影响。研究发现,胞外基质的屏障作用、耐药基因的表达等机制与生物被膜耐药性的产生密切相关。本文就白色念珠菌生物被膜的形成过程、结构组成、形成的影响因素、现有研究模型、耐药机制和治疗策略等几个方面介绍近年来的研究进展。     

膜生物反应器的研究进展

膜生物反应器是近年来发展的废水处理新技术,具有活性污泥浓度高、污泥龄长、占地面积小、投资省的特点。利用膜生物反应器进行污水处理不仅可以大大节约水资源,还可以大大节约能源,节省设备和运行费用,已成为二十一世纪研究热点。膜生物反应器是通过高效膜分离技术与活性污泥相结合,增大污泥中的特效菌来加快生化反应速率,提高废水处理效果。目前处理对象已从生活污水扩展到高浓度的有机废水和难降解的工业废水。本文综述了膜生物反应器在废水中的应用研究情况,并分析比较了各种膜材质的特点、适用范围以及膜的污染因素和清洗方法,展望了膜生物反应器的应用前景及进一步研究方向。     

铜绿假单胞菌生物被膜对抗菌药物作用影响的实验研究

细菌生物被膜形成在难治性感染中起重要作用,本实验在体外进行铜绿假单胞菌生物被膜与抗菌药物作用的研究。铜绿假单胞菌在生理盐水特氟隆系统孵育6d,可在特氟隆表面上形成细菌生物被膜(Biofilm),经扫描电镜证实,它包裹在微菌落表面。应用环丙氟哌酸,甲红霉素,罗红霉素,穿心莲作用于生物被膜细菌并观察结果。发现与2倍MIC环丙氟哌酸作用4h后,悬浮细菌存活率降至002%,但生物被膜细菌存活率则为41%,当10μg/mL甲红霉素,12μg/mL罗红霉素,005g/mL穿心莲分别与环丙氟哌酸联合应用时,生物膜细菌存活率分别降至02%,05%和27%。结果表明生物被膜细菌对环丙氟哌酸的抵抗力较悬浮细菌明显增强,而环丙氟哌酸分别与甲红霉素,罗红霉素,穿心莲联合应用则有明显抑菌作用。推测此种联合用药方式可能提高对难治性感染的治疗效果     

生物组织光热响应及其实验研究

基于激光与生物组织相互作用机理,概述了生物组织的光热响应过程。在此基础上对光热响应所建立的温度场的常用测量技术进行比较,并分别用热电偶和热成像设备进行实验测量。研究结果不仅具有重要的参考价值,对指导临床也有一定的意义。     

超导生物磁强计与生物磁学研究

生物磁学研究在器官、细胞和分子三个水平进行。生物磁场与生物电场的研究相比,最大的优越性在于磁信号较少受容积电流的影响,因此可对源电流产生部位进行较精确的三维空间定位。     

生物垃圾处理过程中渗滤液混凝处理的实验研究

通过对混凝剂(PAS)用量、酸度、温度对垃圾处理过程中渗滤液混凝效果影响的研究,结果表明:用聚合硫酸铝进行混凝处理时,对渗滤液的氨氮处理效果不佳,对CODcr和浊度处理效果甚佳.根据三因素三水平的正交实验,得出处理过程中三个因素对CODcr去除率影响的主次关系为:pH＞聚合硫酸铝的用量＞温度.验证试验结果表明:混凝剂加入量15mL(10%)、pH为6.7、温度为50℃时为最优化工艺条件,CODcr去除率达到76.2%.     

The survival of anaerobes during sewage treatment employing biological filter beds

During the passage of sewage through a typical treatment plant employing biological filter beds and operating under dry weather flow conditions, about 7% of the input of anaerobic organisms survive to be released in the effluent. The greatest fall in numbers occurs in the first of two primary settling tanks operating in series and during passage through the filter beds. The predominant organisms were Bacteroides species, gram-positive cocci and clostridial species. There is no significant difference in the rate of survival of any of the genera through the different stages of treatment.     

Changes in biofilm structure during the colonization of chalcopyrite by Acidithiobacillus thiooxidans

Biofilms of Acidithiobacillus thiooxidans were grown on the surface of massive chalcopyrite electrodes (MCE) where different secondary sulfur phases were previously formed by potentiostatic oxidation of MCE at 0.780?≤?E _an?≤?0.965 V (electrooxidized MCE, eMCE). The formation of mainly S⁰ and minor amounts of CuS and S _n ^2? were detected on eMCEs. The eMCEs were incubated with A. thiooxidans cells for 1, 12, 24, 48, and 120 h in order to temporally monitor changes in eMCE's secondary phases, biofilm structure, and extracellular polymeric substance (EPS) composition (lipids, proteins, and polysaccharides) using microscopic, spectroscopic, electrochemical, and biochemical techniques. The results show significant cell attachments with stratified biofilm structure since the first hour of incubation and EPS composition changes, the most important being production after 48–120 h when the highest amount of lipids and proteins were registered. During 120 h, periodic oxidation/formation of S⁰/S _n ^2? was recorded on biooxidized eMCEs, until a stable CuS composition was formed. In contrast, no evidence of CuS formation was observed on the eMCEs of the abiotic control, confirming that CuS formation results from microbial activity. The surface transformation of eMCE induces a structural transformation of the biofilm, evolving directly to a multilayered biofilm with more hydrophobic EPS and proteins after 120 h. Our results suggest that A. thiooxidans responded to the spatial and temporal distribution and chemical reactivity of the S _n ^2?/S⁰/CuS phases throughout 120 h. These results suggested a strong correlation between surface speciation, hydrophobic domains in EPS, and biofilm organization during chalcopyrite biooxidation by A. thiooxidans.     

Role of the biological properties of vaginal lactobacilli in colonization process

The biological properties of vaginal lactobacilli strains with different colonization capacity were studied. As revealed in this study, colonization depended on the characteristics of species, individual elements of intrageneric antagonism, adhesion, resistance to antibacterial factors and the capacity for producing lysozyme. These properties of lactobacilli ensured the possibility of their adaptation to the conditions of the environment, manifested by its bacterial contamination. The data obtained in this study may be used for the study of symbiotic relationships between nonpathogenic bacteria with the host organism.     

微生物技术在医疗废水处理中的应用

医院污水含有多种病菌、病毒及寄生虫,其直接危害和潜在危害都是显而易见的,因此,进行医疗废水治理,已成为当务之急。微生物处理主要是通过采用活性污泥法、生物接触氧化法、膜生物反应器、曝气生物滤池法等对污水进行处理,从而有效去除水中的有机物,破坏病原微生物赖以生存的物质基础和保障消毒效果。不同的处理工艺各有优缺,适合于不同规模的医院。     

Removal of bacterial indices of pollution during sewage treatment via rotating biological contactor

Summary Two rotating biological contactors (RBC), one bench scale and the other pilot-plant scale, were assessed by using bacterial indices of pollution. The removal efficiency for the pilot RBC was much better than that obtained under laboratory conditions. However, the residual bacterial densities were high enough to represent a potential health hazard. In addition, five different serotypes of enteropathogenic Escherichia coli were isolated from influent and three from effluent samples and 45% of the tested strains were multiple antibiotic resistant.     

Influence of the sulfur species reactivity on biofilm conformation during pyrite colonization by Acidithiobacillus thiooxidans

Massive pyrite (FeS₂) electrodes were potentiostatically modified by means of variable oxidation pulse to induce formation of diverse surface sulfur species (S _n ^2?, S⁰). The evolution of reactivity of the resulting surfaces considers transition from passive (e.g., Fe_1?x S₂) to active sulfur species (e.g., Fe_1?x S_2?y , S⁰). Selected modified pyrite surfaces were incubated with cells of sulfur-oxidizing Acidithiobacillus thiooxidans for 24 h in a specific culture medium (pH 2). Abiotic control experiments were also performed to compare chemical and biological oxidation. After incubation, the attached cells density and their exopolysaccharides were analyzed by confocal laser scanning microscopy (CLMS) and atomic force microscopy (AFM) on bio-oxidized surfaces; additionally, S _n ^2?/S⁰ speciation was carried out on bio-oxidized and abiotic pyrite surfaces using Raman spectroscopy. Our results indicate an important correlation between the evolution of S _n ^2?/S⁰ surface species ratio and biofilm formation. Hence, pyrite surfaces with mainly passive-sulfur species were less colonized by A. thiooxidans as compared to surfaces with active sulfur species. These results provide knowledge that may contribute to establishing interfacial conditions that enhance or delay metal sulfide (MS) dissolution, as a function of the biofilm formed by sulfur-oxidizing bacteria.     

Evolution of biofilms during the colonization process of pyrite by Acidithiobacillus thiooxidans

We have applied epifluorescence principles, atomic force microscopy, and Raman studies to the analysis of the colonization process of pyrite (FeS₂) by sulfuroxidizing bacteria Acidithiobacillus thiooxidans after 1, 15, 24, and 72 h. For the stages examined, we present results comprising the evolution of biofilms, speciation of S_n²⁻/S⁰ species, adhesion forces of attached cells, production and secretion of extracellular polymeric substances (EPS), and its biochemical composition. After 1 h, highly dispersed attached cells in the surface of the mineral were observed. The results suggest initial non-covalent, weak interactions (e.g., van der Waal’s, hydrophobic interactions), mediating an irreversible binding mechanism to electrooxidized massive pyrite electrode (eMPE), wherein the initial production of EPS by individual cells is determinant. The mineral surface reached its maximum cell cover between 15 to 24 h. Longer biooxidation times resulted in the progressive biofilm reduction on the mineral surface. Quantification of attached cell adhesion forces indicated a strong initial mechanism (8.4 nN), whereas subsequent stages of mineral colonization indicated stability of biofilms and of the adhesion force to an average of 4.2 nN. A variable EPS (polysaccharides, lipids, and proteins) secretion at all stages was found; thus, different architectural conformation of the biofilms was observed during 120 h. The main EPS produced were lipopolysaccharides which may increase the hydrophobicity of A. thiooxidans biofilms. The highest amount of lipopolysaccharides occurred between 15–72 h. In contrast with abiotic surfaces, the progressive depletion of S_n²⁻/S⁰ was observed on biotic eMPE surfaces, indicating consumption of surface sulfur species. All observations indicated a dynamic biooxidation mechanism of pyrite by A. thiooxidans, where the biofilms stability and composition seems to occur independently from surface sulfur species depletion.