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。     

城市污水短程硝化的控制策略及对污泥种群的影响

采用有效容积为54m3的大型中试序批式活性污泥处理(SBR)反应器,研究了在常温下处理碳氮比(C/N)平均值为2.16的以生活污水为主的实际城市污水时短程硝化的实现和稳定问题.试验结果表明,采用分段进水的运行模式,使出水总氮(TN)达到了小于3mg/L的深度脱氮效果.同时通过对SBR反应阶段的实时控制,优化了污泥种群结构,从而实现了温度为12～26℃、平均溶解氧(DO)浓度在2.5mg/L以上的环境条件下长期稳定的短程硝化反硝化,系统维持95%以上的亚硝化率稳定运行180天以上.应用荧光原位杂交(FISH)技术对系统中的氨氧化菌(AOB)和亚硝酸盐氧化菌(NOB)的数量进行了分析,结果也证明了系统中氨氧化菌在硝化菌中占绝对优势,亚硝酸盐氧化菌已逐步被淘汰.     

以氯化和时间控制实现亚硝化型硝化反硝化

研究了以氯化方法在生物脱氮工艺中实现亚硝化型硝化反硝化的可行性。试验表明，借助氯的作用和硝化反应中的延迟时间的影响，可以在常温下保持很稳定的完全的亚硝化型硝化反硝化反应。在投加氯形成短程硝化反应后，不加氯，仅采取控制曝气时间的手段时，这种完全的亚硝化型硝化反硝化反应也可以保持至少20天。试验结果表明，硝化菌应是被杀死而不是仅仅被抑制。在实际工艺应用中，亚硝化型硝化反硝化所带来的益处可以弥补在反应过程中投加氯的费用，因此，在SBR中以氯化的方法结合时间控制以达到亚硝化型硝化反硝化是可行的。     

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。     

短程硝化反硝化技术研究

目前,高效、低耗去除水中氦污染物是国内外广泛关注的环境问题,短程硝化反硝化脱氮技术则是当前的研究热点。本论文针对短程硝化反硝化脱氨的机理和影响因素进行了研究,以深入理解短程硝化反硝化现象,对发展可持续污水生物处理工艺具有重大推动意义。     

曝气生物滤池处理工业综合废水提标改造技术研究

针对曝气生物滤池工艺不具备脱氮除磷功能,特别是在处理工业综合废水时出水不能稳定达标排放的问题,提出了"化学除磷+气浮除油+水解酸化+前置反硝化曝气生物滤池"的全流程处理工艺,并通过中试研究对处理流程以及各个处理单元运行参数进行了优化,在水解酸化2.0 h,投加混凝剂硫化铁量为40.0 mg/L,气浮溶气压力3.5 kg/cm2,AO池125%回流比,水力停留时间为20.0 min的条件下,其出水达到国家一级A排放标准的要求。并对升级改造的建设和运行费用进行了核算,为同类污水处理厂的升级改造工程提供理论依据和数据支持。     

温度对亚硝酸型硝化/反硝化的影响

以间歇式活性污泥法（SBR）法处理啤酒废水，系统考察了温度变化对亚硝酸型硝化／反硝化的影响。结果表明：温度维持在30℃得到的亚硝酸型硝化的污泥，运行在常温（19．5－23．5℃）50周期，硝化类型转变为硝酸型硝化。而后，逐渐升温，硝化类型逐渐转变为亚硝酸型硝化。当温度达到28－29℃时，硝化类型为稳定的亚硝酸型硝化，硝化反应结束时NO2^--N/NOx^--N平均维持在82．2％－83．5％。28－29℃是本试验条件下亚硝酸型硝化的临界温度。而且不论是亚硝酸型硝化／反硝化还是完全硝化／反硝化，DO、ORP、pH在脱氮过程中的变化规律基本相同，可以作为SBR法脱氮过程的控制参数。     

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。     

处理城市污水的反硝化脱氮除磷新工艺研究进展

反硝化脱氮除磷可以实现同步反硝化脱氮和除磷,代表了当前污水处理可持续发展战略的发展趋势。本文对反硝化脱氮除磷的新工艺进行了重点介绍,这些工艺充分发挥了反硝化聚磷菌的优势,可提高处理效率、简化操作、降低处理费用,成为目前脱氮除磷工艺技术研究的热点和重点。     

浅谈脱氮新工艺

传统的生物脱氮工艺存在着工艺流程长,脱氮效率低,占地大,成本高等缺点。随着新型脱氮技术的不断发展,突破了传统脱氮工艺的局限,涌现了一批新型脱氮工艺。本文综述短程硝化(SND),厌氧氨氧化(ANAMMOX),好氧反硝化(aerobic denitrification)等目前热点研究的脱氮新工艺,阐述了脱氮原理,影响因素,工艺特点,并与传统脱氮工艺进行对比。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

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.