现代污水处理生物脱氮除磷工艺分析

概述生物脱氮除磷机理,包括生物脱氮、生物除磷机理以及同步脱氮除磷机理、反硝化脱氮除磷机理。分析不同生物脱氮除磷机理的处理工艺,并阐述了脱氮除磷工艺的发展趋势。     

污水除磷技术的研究进展

简单介绍化学除磷技术及传统的生物除磷工艺,分析生物除磷技术的发展趋势,并对以反硝化除磷工艺为代表的生物除磷新技术的工艺原理及特点做了介绍。认为,以目前我国的经济和发展情况,生物与化学联合除磷将是水处理技术的发展趋势,但化学除磷试剂对生物处理系统性能可能会产生影响,还需进一步的研究以促进其应用和发展。     

城镇污水处理厂深度除磷

生物除磷工艺后增加化学除磷能使出水稳定,达到《城镇污水处理厂污染物排放标准》中一级A标准,阐述化学除磷的原理、药剂的选择和适宜的投加点,以及深度除磷的"生物除磷+化学除磷+物理除磷"组合工艺。     

反硝化除磷工艺及其微生物学原理

反硝化除磷是通过反硝化聚磷菌的代谢作用,同时完成过量吸磷和反硝化过程,在达到同步生物脱氮除磷的目的同时,解决了生物脱氮和生物除磷之间相对独立的、相互竞争的矛盾。就此项新技术的微生物学原理及其新工艺进行了重点介绍。     

污水生物除磷脱氮新技术探讨与展望

概述了传统的生物除磷脱氮的基本原理与局限性,并介绍了新的除磷脱氮理论及典型工艺,指出反硝化除磷脱氮技术是未来污水生物处理可持续的发展方向。     

城镇污水处理厂不同化学除磷方式的对比试验研究

通过同步和后置化学除磷方式的对比试验,分析了两种投药方式下除磷的去除效果,结果显示在反应充分的情况下,同步和后置两种投药方式的除磷效果相差不大.在实际生产中,两种方式各有利弊,应综合考虑厂区实际情况,选择适合的化学除磷方式.     

污水反硝化除磷产电装置启动研究

反硝化除磷产电装置以连续流双污泥反硝化除磷工艺为基础,以厌氧池和中沉池分别作为微生物燃料电池的阳极室和阴极室,以模拟的生活污水作为处理对象。反硝化除磷产电装置稳定运行2个月后,COD、氨氮和磷的平均去除率分别为65.56%,57.16%和53.79%,最高去除率分别达到了75%,75%和65%,产生的电压和电流强度的平均值分别为0.58 V和6.31 m A,最高电压值达到了0.7 V。反硝化除磷产电装置的成功启动与运行,不仅去除了生活污水中的COD、氨氮和磷,同时产生了稳定的电能,实现了反硝化除磷与微生物燃料电池的耦合,为反硝化除磷产电工艺的深入研究奠定了基础。     

反硝化除磷理论及其影响因素分析

综述传统生物除磷机理及反硝化除磷机理,并分析反硝化除磷的影响因素和未来发展新思路。     

反硝化除磷机理及其工艺影响因素研究进展

污水生物脱氮除磷是防止水体富营养化问题的有效途径之一,反硝化除磷菌在反硝化的同时完成过量摄磷,较传统生物脱氮除磷具有节约碳源、节省曝气量和污泥产量低等优点,是目前脱氮除磷工艺开发的研究热点.介绍当前反硝化除磷菌的生物学机理及其工艺运行的主要影响因素.     

节能型泥水自循环阶式A2/O脱氮除磷工艺

介绍了节能型泥水自循环阶式A^2／O脱氮除磷工艺，阐述了该工艺的基本组成、运行过程与技术特点，总结了其脱氮除磷效果，通过工艺节能及动态优化控制节能两方面大大降低了本工艺的处理能耗。并且通过示范工程的处理效果进一步证明了本工艺的高效性与节能性。     

Enhancing filter cake removal by engineering parameter optimization for clean development of fossil hydrogen energy: A numerical simulation

Long-term zonal isolation is crucial for the development of fossil hydrogen energy, while efficient filter cake removal is the basis for successful zonal isolation. However, enhanced filter cake removal usually relies on adding chemicals into preflush fluid, which are potential pollutants to the environment. In this study, engineering parameter optimization is used to realize enhanced filter cake removal. Firstly, filter cake removal was identified as multiple-phase fluid flow, and a new three-fluid numerical model was established accordingly. The effects of five engineering parameters on the removal efficiency were simulated and the results showed that borehole enlargement and casing eccentricity reduced removal efficiency. The critical borehole deviation angle and casing rotation speed for optimal removal efficiency were 45° and 40 rpm, respectively, while the removal efficiency monotonously increased with flushing velocity. After all engineering parameters were optimized, the maximum removal efficiency was as high as 89.34%, which was comparable to that achieved by using potentially polluting chemicals. The borehole enlargement rate was identified as the most sensitive parameter, followed by casing eccentricity, flushing velocity, borehole deviation angle, and casing rotation speed subsequently. Two empirical models to predict removal efficiency were developed for convenient field application. Briefly, the complex removal behaviors of the filter cake are better understood for reducing the risks of failed zonal isolation and avoiding chemical overuse, which potentially contributes to the cleaner and more environment-friendly production of fossil hydrogen energy.     

颗粒层除尘器过滤和清灰方式的优化

分析了移动床颗粒层除尘器存在颗粒层间隙增大和颗粒错位等影响除尘性能的问题,并优化出能克服这些问题的新型结构和过滤方式的颗粒层除尘器;介绍了新型颗粒层除尘器的结构和特点,特别是组合流化床清灰机构能实现颗粒层的快速清灰;建立了除尘器床层压降的数学模型,通过实验摸索出颗粒层流化清灰规律和除尘器的过滤性能。理论和实践表明,新型颗粒层除尘器的除尘性能优于其它颗粒层除尘器,能实现了除尘和清灰一体化,清灰过程更简便。     

改性前后沸石及其再生脱氮效果对比分析

基于天然沸石的结构及其组成成分,阐述了天然沸石脱氮性能、改性方法及改性沸石脱氮性能、再生方法及其再生沸石脱氮性能,综合对比分析了天然沸石、改性沸石和再生沸石的脱氮效果。结果表明,利用天然沸石进行生物再生并循环利用,不仅节能、避免产生二次污染,又能要脱氮的同时去除其它污染物,而且可长期使用,是一种处理微污染水体的新方法,从而为解决水环境富营养化问题提供了新的思路。     

Numerical investigation of water droplet removal characteristics in novel block channels of PEMFC using dynamic wettability model

Liquid water transport and removal is one of the critical issues in the proton exchange membrane fuel cell (PEMFC) for achieving good performance and durability. In this study, two novel channels with different blocks are designed to study their effects on water removal using the volume of fluid (VOF) model considering the dynamic contact angle effect. It is found that compared with the conventional straight channel, both the one-block and two-block channels can promote liquid water removal. The one-block channel leads to faster water movement and removal on the gas diffusion layer (GDL) surface, but results in a much higher pressure drop. The separated two-block channel directly drags water away from the GDL surface by the capillary wicking effect of the block surface, achieving both faster water removal and smaller pressure drop. Effects of the droplet size, air velocity and static contact angle of GDL surface on water removal are investigated comprehensively in both the novel channels, as well as the conventional straight channel, with particular attention on the variations of water removal time, water coverage ratio and pressure drop.     

移动颗粒层过滤高温除尘器中循环清灰系统的试验研究

介绍能连续稳定高效运行的颗粒介质气力循环清灰系统,包括颗粒介质供在,传输系统和清灰器结构优化试验研究,系统的运行规律证明连续稳定循环清灰可行,对移动颗粒层过滤高温除尘技术开发有较大参考价值。     

单缸低参数汽轮机末级排汽湿度的热力分析

采用VB语言,通过动态链接库的调用,编制了低参数单缸汽轮机热力计算程序.应用此程序,在不同设计参数下,针对无抽汽除湿、级间抽汽除湿和除湿级除湿3种方案,研究了机组末级湿度的变化.结果表明,进汽压力、进汽温度和排汽压力三者对末级湿度的影响不同,进汽温度对末级湿度的影响最大,进汽压力次之,排气压力最小.在本研究所提参数条件下,满负荷运行很难保证末级出口湿度要求,需采用有效的内部除湿措施.研究也表明,在不同位置抽汽除湿和除湿级除湿对机组末级湿度影响较大,在相同的设计参数下,在机组的第四级后抽汽除湿对机组末级湿度的影响最大.在相同的除湿效率下,除湿级位置每向后移动一级,使末级湿度降低约1%,随除湿级位置后移,除湿效率对末级湿度的影响增大.     

磁稳流化床除尘装置的设计与验证

介绍了一种磁稳流化床除尘装置的设计方法,特别就装置关键部件的设计重点做了说明;同时对影响该装置除尘效率的主要因素进行了实验验证,实验结果表明,保持除尘装置处于磁稳状态是获得高效除尘的关键;床层高度、气体表观流速比等也对除尘效率有一定的影响。     

酸性NaClO_2溶液同时脱硫、脱硝的试验研究

以NaClO2溶液为吸收剂,在自行设计的小型鼓泡反应器中进行了烟气同时脱硫、脱硝的实验研究,分析了影响脱除效率的各种因素及规律.试验发现,NaClO2初始浓度、吸收溶液初始pH值、吸收液温度、SO2和NO初始浓度等对脱除效率影响较大;在确定的最佳试验条件下,脱硫、脱硝效率分别达到100%和95.2%.另外还利用光化学方法分析了脱硫、脱硝产物,结果表明:脱硫产物主要为SO24-,脱硝产物主要为NO3;在此基础上,提出了酸性NaClO2溶液脱硫、脱硝的反应机理.     

Dominant frequency of pressure drop signal as a novel diagnostic tool for the water removal in proton exchange membrane fuel cell flow channel

In this work, a transparent assembly was self-designed and manufactured to perform ex situ experimental study on the liquid water removal characteristics in PEM fuel cell parallel flow channels. It was found that the dominant frequency of the pressure drop across the flow channels may be utilized as an effective diagnostic tool for water removal. Peaks higher than 1 Hz in dominant frequency profile indicated water droplet removals at the outlet, whereas relatively lower peaks (between 0.3 and 0.8 Hz) corresponded to water stream removals. The pressure drop signal, although correlated with the water removal at the outlet, was readily influenced by the two phase flow transport in channel, particularly at high air flow rates. The real-time visualization images were presented to show a typical water droplet removal process. The findings suggest that dominant frequency of pressure drop signal may substitute pressure drop as a more effective and reliable diagnostic tool for water removal in PEM fuel cell flow channels.     

The effects of slash and stump removal on productivity and quality of forest regeneration operations—preliminary results

The object of this study was to survey the effects of slash and stump removal on work productivity and work quality, as well as on the technology of forest regeneration operations. Site preparation and planting were studied in different conditions. Slash and stump treatments “removal” and “no removal” were established at each site. Time studies were made during site preparation and planting. The quality of mounding and planting was analysed by measurements of the seedlings.After slash removal, the increase of work productivity (E₀) in mechanized planting was 18 per cent with a Bräcke planting machine and 0 per cent with an Ecoplanter planting machine. The quality of mechanized planting was slightly improved by slash removal.After slash removal, the productivity (E₀) of excavator-mounted mounders was 22 per cent higher with a mounding blade and 53 per cent higher with a ditching bucket. The quality of mounding was the same for both slash treatments. The productivity (E₀) of three forwarder-mounted mounders was 5 per cent lower after slash removal, but at the same time the quality of the mounding was much better.In combined stump extraction and mounding, the time consumption of the mounding phase was about 40 per cent lower than for separate mounding after stump removal.The results show that slash and stump removal will improve work productivity and quality when using mechanized mounding and planting methods. In addition after slash and/or stump removal it may be possible and cost-effective to use new planting and site preparation methods based on forwarder-mounted mounders.