低溶解氧短程硝化及同步脱氮研究

采用SBR反应器,以实际生活污水为研究对象,通过实验研究了在常温条件下通过控制低溶解氧(DO)实现短程硝化的可行性及控制条件.在曝气量由60 L·h-1逐渐降低到28 L·h-1的过程中,实现了由全程硝化到短程硝化的转变,亚硝酸盐积累率达到95%以上,出水硝态氮稳定在2.0mg·L-1以下.在低溶解氧短程硝化过程中,伴随着显著的同步脱氮:曝气量为32 L·h-1条件下实现了平均总氮去除率达54.6%.在实现短程硝化后,再次提高曝气量为40L·h-1时,短程硝化可以稳定保持.实验结果表明,通过控制低溶解氧可以实现常温条件下生活污水的短程硝化,过程中同步脱氮效果明显;系统可以在相对较高的溶解氧浓度下稳定运行.     

用实时控制SBR实现生活污水的短程硝化

采用间歇式活性污泥法 (SBR)处理生活污水 ,根据反应过程中DO、pH值和氨氮、亚硝酸氮、硝酸氮浓度变化的相应关系 ,控制曝气终点 ,实现了短程硝化。研究表明 ,短程硝化与全程硝化是相对的 ,没有绝对的短程硝化。对亚硝酸菌占绝对优势的混合液 ,进行长时间延时曝气 ,短程硝化可向全程硝化转化。实时控制是实现短程硝化的关键。采用实时控制方法 ,在 32± 1℃ ,亚硝酸氮积累率长期稳定地维持在 99%以上。在 2 1±1℃ ,通过控制低溶解氧浓度和曝气时间可实现短程硝化。     

亚硝化偶联硝化过程动力学及验证

基于活性污泥模型ASM2D,建立了亚硝化及硝化过程动力学模型,给出了动力学模型涉及到的过程速率、计量学系数和动力学参数,并构建了以pH和温度为可变参数的最大比生长速率表达式。用该模型对不同运行条件下的硝化过程进行了模拟,模拟结果显示:随着溶解氧的升高,历经NH_4~+-N氧化率和NO_2~+-N累积率随之升高的短程硝化过程,以及NO_2~--N进一步氧化为NO_3~--N的完全硝化过程;通过控制反应器的曝气时间在0.2d左右,污泥停留时间(SRT)在氨氧化细菌(AOB)和亚硝酸盐氧化细茵(NOB)最小停留时间之间,可实现亚硝酸盐的高效积累。同时还利用模型考察了短程硝化启动及稳定运行的特性,也进行了模拟值与实验实测值的比对,结果表明模型能够准确地模拟两步硝化过程从启动阶段到稳定短程硝化的变化趋势,模拟值与实测值的误差在合理范围之内。     

模糊控制强化生物除磷SBR系统的除磷过程

采用在线ORP和pH仪对两个平行的强化生物除磷(EBPR)SBR反应系统的厌氧放磷、缺氧吸磷和好氧吸磷过程进行监测。针对聚糖菌(GAO)和聚磷菌(PAO)的竞争和影响PAO和反硝化聚磷菌(DPAO)的各种因素,验证了以氧化还原电位(ORP)和pH作为除磷过程模糊控制参数的可行性和有效性。在此基础上,确立了厌氧／好氧(A／O)SBR系统和厌氧／缺氧(A2)SBR系统除磷过程的模糊控制策略。对ORP和pH的在线检测不仅可以模糊控制厌氧放磷、缺氧吸磷和好氧吸磷过程所需时间,节约能源优化处理效果,而且可以指示系统运行效果和功能微生物种群的竞争行为。     

缺氧-好氧膜生物反应器处理高浓度氨氮废水

采用前置缺氧/好氧膜生物反应器处理高浓度氨氮废水,对反应器的硝化和反硝化性能以及污泥特性进行了研究.研究结果表明:适宜的pH、DO、T下,在容积负荷1.5kgNH4 -N/(m3·d)以下时,出水平均NH4 -N值在1 mg/L左右,硝化率保持在99%以上;在容积负荷为1.0 kgNH4 -N/(m3·d),C/N为3.2,回流比为3时,硝化率为99%,总氮去除率达到83.34%.缺氧池与好氧池的污泥浓度后期分别稳定在6.5～7.0 g/L和9.5～10.0 g/L,两池污泥VSS/SS长期稳定在89%左右,说明污泥没有无机成分的积累.     

一体化厌氧氨氧化-反硝化固定微生物反应器协同脱氮研究

采用厌氧氨氧化(ANAMMOX)工艺的厌氧上流式固定化微生物反应器处理含有机物的高浓度含氮废水,考察ANAMMOX与反硝化协同脱氮效果。试验结果显示:在一定范围内,NH4+-N和NO2--N进水负荷不会对ANAMMOX与反硝化协同脱氮造成明显影响,当进水负荷为301～800mg/L时,系统对NH4+-N、NO2--N和TN的去除率分别达到93.3%、98.6%和90.3%的较高水平;当COD浓度为800～850mg/L时,COD对ANAMMOX与反硝化协同脱氮基本不影响,并可实现95.7%的COD去除率。同时,NO3--N浓度、N2产量、pH值和生物相存在的特征性变化,也表明ANAMMOX与反硝化协同作用良好。     

城市生活污水经A/O除磷亚硝化试验研究

随着人们用水污染的日益严重,专业人员开始研究有效绿色的污水处理方法。厌氧氨氧化技术是目前已知的最经济的生物脱氮技术,是指在厌氧或缺氧条件下,ANAMMOX菌将氨氮和亚氮按照1:1的比例转变成氮气的生物过程。本实验采用SBR烧杯对比试验,本文对于亚硝化技术进行了深入研究,探索将试验进程控制在全部亚硝化还是部分亚硝化范围内的问题,以期为厌氧氨氧化技术应用于城市生活污水提供技术支持。     

BIOSEP膜-生物反应器处理城市污水

法国威力雅水务(Veolia Water)开发的膜生物反应工艺--BIOSEP技术,其城市污水处理应用工程之一的德吕镇(Thelus)污水站已运行4年.在经过长期运行后,对其进行处理效果进行了一次为期3周的评估.在进水sS最高达868 mg/L、CoD(化学需氧量)在932～1 890 mg/L的情况下,污水站出水SS(悬浮固体)小于2 mg/L,COD小于30 mg/L,去除率在98%以上.但其存在出水中硝酸盐氮过高的问题.而对于膜组件的运行中膜堵塞的问题,4年实际运行过程中,在化学浸泡清洗对膜通量的提高效率有限的情况下,优化膜滤运行方式对预防膜堵塞、稳定膜通量有着良好的效果.     

HLS-无机膜生物反应器的制备与应用

采用接触氧化法和陶瓷膜相结合设计制备了无机膜生物反应器.在温度10～28℃、pH>6.5、HRT(水力停留时间)8 h、SRT(污泥停留时间)130 h、MLSS(混合液悬浮固体浓度)10.2 g/L、膜面流速5.0～7.0 m/s,膜操作压力0.20 MPa的条件下处理生活污水,膜通量为:130～170 L/(h·m2),HLS-无机膜生物反应器对COD的去除率可达99%以上.出水NH3-N为3～6 mg/L.浊度为3～8 NTU.     

MBR中同步硝化反硝化及异养硝化现象试验研究

在以限制混合液溶解氧浓度方式运行的MBR反应器中,通过改变进水COD/TKN、混合液DO浓度等工艺参数,研究了对系统中同步硝化反硝化(SND)过程的影响因素.根据试验结果探讨了MBR系统中所实现的SND机理,同时对系统中存在的异养硝化菌进行了分离培养,并对其硝化特性进行了初步研究分析.试验结果表明:影响系统SND的主要因素是进水COD/TKN和反应器中控制的混合液DO浓度,系统中存在一定量的异养硝化菌.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.