微生物胞外电子传递过程强化机制及污染物高效转化

微生物水处理技术因运行成本低、处理量大、环境影响小等优点,被广泛的用于市政污水和工业废水的处理.微生物水处理的本质过程是生物催化氧化,涉及不同微生物种群间物质、能量和电子传输过程,而微生物胞外电子传递过程是影响其处理效率的关键因素之一.本研究立足于微生物氧化的原理,从介体材料强化、光电磁强化及微生物电化学强化等角度,系统论述了铁基材料、碳基材料、光、电、磁等对微生物电子传递过程的影响与机制.在此基础上,本论文总结了微生物电化学系统原理,分析了该系统中各类强化材料、强化技术对微生物胞外电子传递的影响,揭示了强化条件下污染物高效转化的作用机制,介绍了基于各种强化原理的系统构建因素及应用现状,并展望了该技术的发展趋势及存在的挑战.     

干湿交替对自然沟渠沉积物反硝化速率的影响

以川中丘陵区自然沟渠沉积物为研究对象,设置低强度、中强度、高强度的干湿交替频率和长期淹水对照处理,运用室内原状土柱-乙炔抑制培养法和实时荧光定量PCR技术,研究了干湿交替对自然沟渠沉积物反硝化速率及相关功能基因的影响.结果表明：在试验模拟过程中,干湿交替显著降低了沉积物中NH₄⁺-N和DOC含量,沉积物中NO₃^--N含量则表现为先增加后减少的趋势.沉积物反硝化速率均值表现为中强度（266.42 μg·m^-2·h^-1） > 高强度（199.10 μg·m^-2·h^-1） > 低强度（152.93 μg·m^-2·h^-1） > 长期淹水（9.57 μg·m^-2·h^-1）.干湿交替增加了反硝化功能基因的拷贝数（p<0.05）,nosZ基因拷贝数在实验前后无显著差异;低强度和中强度处理的nirK基因拷贝数在实验前后差异显著,中强度处理的nirS基因拷贝数在实验前后差异显著.Pearson相关分析结果表明,沉积物的反硝化速率与NO₃^--N含量、ORP和nirK基因拷贝数呈显著正相关（p<0.05）.干湿交替可能主要通过改变沉积物的NO₃^--N含量、ORP和nirK基因拷贝数影响沉积物反硝化速率.     

调水和季节变化对河流沉积物古菌群落的影响

采用高通量测序方法分析了汾河引黄河段沉积物中古菌群落的组成、相对丰度、多样性,及其与环境因子之间的相关性,揭示引黄调水和季节变化对古菌群落结构的影响.结果表明：冬季时水体SO₄^2-、Cl^-、Na⁺、K⁺等离子浓度、EC、TDS （总溶解固体含量）、沉积物碱解氮和速效磷含量是影响古菌群落结构的主要环境因子,夏季时沉积物pH值、有机质和速效磷含量是主要环境因子.黄河水汇入后河流沉积物中出现了上游未检测到的古菌类群,如TMEG （norank_f_Terrestrial_Miscellaneous_Group）、洛基古菌等.引黄还可以使甲烷杆菌和海洋古菌等在不适宜其生存的时期活跃起来,丰度明显增加.冬季引黄河段古菌数量增加,多样性提高,夏季则相反.季节变化改变了古菌群落的空间相似关系,然而引黄的贡献较季节变化大.研究河段沉积物中古菌群落组成丰富,包含多种至今未被分类定义的古菌.     

Experimental and numerical analysis of a helical coil solar cavity receiver: Thermal oil as the heat transfer fluid

The paper presents the novel design of double glazing helical coil solar cavity receiver for solar thermal applications. Performance model has been developed for the experimental setup based on energy balance equations. The results obtained were compared with horizontal tube receiver for the same experimental setup. The result shows that the 87.96% improvement in the convective heat transfer coefficient for the double glazing helical coil solar cavity receiver. Maximum conversion efficiency achieved is 21% more than that would be obtained for horizontal tube receiver. This paper also investigates how the quality of vacuum degraded with the temperature of the glass cover.     

基于信号流循环的振动试验控制回路分析研究

目的总结分析振动试验信号循环全过程的数学模型及传递关系。方法根据信号传递过程中的作用,将振动设备划分为五类关键设备,并且将信号流在信号转换、信号可测及运动可控等方面的传递关系进行分析汇总,最后给出以控制仪为回路节点的两类开环故障的影响分析。结果通过对信号流循环过程的分析研究,总结了闭环反馈控制过程各环节中的信号传递关系,分析了各关键设备性能对振动试验信号传递的影响,以便于试验人员更好地开展振动试验。结论信号流循环的正常运转是振动试验顺利开展的基础,深入了解信号传递关系和影响因素,可以高质量地开展振动试验。     

热水解污泥在波节管中流动传热的数值研究

利用数值模拟方法,考察了低湍流雷诺数(Re=4 000)情况下热水解污泥在几种型号波节管的管内流动和传热性能,系统研究了波节管的波节高度H、波谷圆角半径r、波节间距P以及波节长度S1对波节管的流动及传热性能的影响。结果表明,在相同管径及管长下,波节管的换热效果明显比光滑管好。由于管内形成径向二次流,湍动剧烈,传热得到强化,但是进出口压差也相应增大。波节高度H对波节管的强化传热起决定性作用,波谷圆角半径r、波节间距P以及波节长度S1主要对流动阻力产生影响。在研究中采用的波节管相对于光滑管,努赛尔数Nu和阻力系数f分别最大增加130%和129%,并且当H=4 mm,r=10 mm,S1=20 mm,S2=25 mm时,综合换热因子η达到最大值2.1。     

A numerical model for drying of spherical object in an indirect type solar dryer and estimating the drying time at different moisture level and air temperature

A numerical model for simultaneous heat and mass transfer was developed for solar drying of spherical objects and the object considered is green peas. Solar collector outlet temperature is assumed as drying chamber temperature and justified through energy balance equations. Assumptions are imposed on heat and mass transfer governing equations without losing the physics of the problem. Discretization is performed by finite difference method with implicit scheme. To generalize, the governing equation and boundary conditions are non-dimensionalized. The set of finite difference equations was solved by Tridiagonal Matrix Algorithm and a computer code in MATLAB was developed to solve them. The drying curves showed two stages of drying, initial, and secondary drying stage. At all drying temperatures and drying time, the center moisture was maximum and it was minimum at the boundary. A percentage of 85.67 surface moisture content and 25.33% center moisture was eliminated in the first 1 hr at 348 K. The product should be dried up to 7.45, 4.74, and 3.74 hr at air drying temperatures of 318, 333, and 348 K respectively, to maintain 10% of the product’s initial moisture content. The result is compared with the experimental result from literature and they are found to be in good agreement.     

出水回流对Anammox颗粒特性及其微生物群落的影响

基于有无回流的EGSB反应器中厌氧氨氧化颗粒污泥的内外部结构和微生物群落差异,从传质、活性和稳定性等角度分析了出水回流对颗粒污泥结构和功能的影响.研究表明,增加回流提供更好的水流条件使得底物能更好的与颗粒污泥接触,反应器在氮负荷率为(3.48±0.32)kg N/(m3·d)的条件下亚硝氮和氨氮的去除率从60％和65％...     

Isolation and characterization of deodorizing bacteria for organic sulfide malodor

Strain JII screened out from different odor origins can efficiently degrade methyl mercaptan and ethanethiol whereas has no ability to remove dimethyl sulfide. The results indicated that the strain JII breaks only the C-SH bond. The optimum temperature and pH of JII are 20-30℃ and 6.0-8.3 respectively. A systematic identificatio nmethod-16S rDNA gene sequence comparison, for deodorizing bacteria was carried out. The 16S rDNA gene sequence analysis of strain JII showed the highest level of 97 % homology to Rape rhizosphere.     

铁矿石和生物炭添加对潜流人工湿地污水处理效果和温室气体排放及微生物群落的影响

人工湿地中基质的种类和填充方式会影响人工湿地中微生物的多样性及丰度,进而影响污水处理效果.通过在温室内构建空白-人工湿地(CW0)、铁矿石-人工湿地(CW1)、生物炭-人工湿地(CW2)和铁矿石+生物炭-人工湿地(CW3)这4组湿地,研究不同填料人工湿地系统的污水处理效果和温室气体排放及微生物群落结构的差异.结果表明,...