吴淞江微污染水源水处理工艺的比较研究

采用预臭氧生物活性炭滤池、生物接触预氧化、PAC吸附预处理三种工艺对吴淞江微污染水源水处理进行研究;常温下,臭氧投加量2 mg/L,预臭氧生物活性炭滤池对氨氮的去除率维持在70%以上,出水NH3-N约1 mg/L,CODMn平均去除率34.16%;生物接触预氧化对氨氮去除率可达80%以上,但CODMn平均去除率只有7.6%;PAC对色度及臭味有良好的去除效果,但对其他物质去除率较低.三种工艺相比,作为水厂改造或备用应急方案,预臭氧生物活性炭滤池为最佳选择.     

高有机物污染原水深度处理工艺选择和运行优化

P市地表原水受到有机物污染,水中CODMn经常高达10mg/L以上,为此,在G水厂的扩建工程中,采用了两级臭氧—生物活性炭深度处理工艺,以保证出水水质安全。水厂运行结果表明,在活性炭吸附饱和后,一级炭池出水CODMn仍有3～5mg/L,需二级臭氧—生物活性炭处理才能使出厂水CODMn小于3mg/L。当前后臭氧分级投加比例为3∶2时,有机物的去除率最高。     

两种填料气浮生物滤池中试研究

针对南方某水厂微污染水源水设计新型气浮生物过滤一体化单元进行颗粒活性炭、陶粒填料对比中试研究,发现两种填料对浊度的处理效果均十分稳定;当进水氨氮<2.5mg/L时,活性炭填料具有更好的处理能力;活性炭填料具有70%左右的CODMn去除率,陶粒填料对CODMn的处理能力波动较大;气浮对混凝后水中氨氮可有约10%的去除率。     

纯氧预曝气-生物过滤组合工艺处理微污染水中试研究

采用中试规模设备研究纯氧预曝气和生物过滤组合工艺对微污染水源水中多种污染物的处理效果。在沉淀池末端进行纯氧预曝气,能够提高溶解氧浓度至9.43~13.05mg/L,比较了活性无烟煤和活性炭两种滤料生物过滤工艺。原水氨氮为3mg/L时,出水氨氮平均值为0.07mg/L,且无亚硝态氮积累,CODMn平均去除率为71.72%,出水CODMn浓度均值为0.94mg/L,铁离子平均去除率为98.29%,出水铁离子浓度均值为0.011 mg/L,对典型臭味物质二甲硫醚的去除率为95.24%。结果表明活性无烟煤和活性炭两种滤料的性能类似。纯氧预曝气-生物过滤组合工艺适用于水厂常规处理工艺改造,对传统水厂技术升级具有重要的价值。     

投加氮源提高臭氧—生物活性炭工艺COD_(Mn)去除效果中试研究

采用中试研究投加氮源(NH4Cl)提高臭氧—生物活性炭工艺去除CODMn的效果。试验结果表明,投加一定量的氮源有利于去除有机物,而过量则无助于去除效果的提高。试验发现,NH4Cl的最佳投加量为0.75mg/L。在最佳投加量下,CODMn总去除率为59.5%,提高了5%左右;生物活性炭对CODMn去除率为36%,提高了6%。     

再生颗粒活性炭在果园桥水厂的应用实践

桐乡市果园桥水厂采用臭氧-生物活性炭深度处理工艺,为了强化处理效果、降低制水成本、减少环境污染,对饱和生物活性炭进行了再生.通过检测,再生炭的碘值恢复率达90%以上,亚甲基蓝值恢复率接近90%,强度略有下降,但仍高达93%,灰分增长了91.5%.再生炭运行当月CODMn去除率高达78.4%,运行半年至今去除率仍达50%左右,处理效果接近新炭水平.采用再生方式比全部更换新炭节省费用50%以上.最后阐述了饱和活性炭再生利用的可行性及必要性.     

生物活性炭滤池中无脊椎动物孳生问题与对策

以南方A、B两座臭氧-生物活性炭深度处理水厂为研究对象,探讨了生物活性炭滤池中无脊椎动物的来源及其生长繁殖特点.研究表明,生物活性炭滤池在运行过程中会孳生无脊椎动物,轮虫是无脊椎动物的绝对优势类群,其次是甲壳类浮游动物.在取水口或泵站采用氯等化学药剂灭活原水中的甲壳类动物,是控制生物在水处理系统繁殖和穿透的重要措施;优化砂滤池的运行参数并加强管理,控制生物进入生物活性炭滤池,是解决甲壳类动物穿透的根本途径.对于生物活性炭中孳生的甲壳类浮游动物,可采用药剂反冲洗和药剂浸泡进行去除和灭活.     

水厂活性炭滤池换炭方式对生产运行的影响

W市Z、X、D水厂的臭氧-生物活性炭滤池已运行超过8年,面临大规模炭滤池换炭问题,为探寻最佳换炭方式,3家水厂分别采用了活性炭滤料的全换和半换2种方式进行对比.主要研究相同水源条件下2种换炭方式对生产运行的影响.研究结果表明,2种换炭方式在并网运行5个月后,活性炭滤料表面生物量稳定,均成功挂膜.相比于半换炭,全换炭方式对CODMn、UV254、TOC和消毒副产物等去除效果更佳,并且可以深入检查配水系统等隐蔽工程.但是,全换炭用炭量大,需要全部更换承托层,总体投入成本较大,短期投资效益较低.因此,选择全换炭还是半换炭方式,各厂应结合自身实际情况确定.     

臭氧-生物活性炭控制有机物和消毒副产物研究

南方某水厂采用的臭氧-生物活性炭给水深度处理工艺稳定运行了6年,为了解工艺长期运行过程中在活性炭性能指标下降后,是否还能有效地去除有机物和消毒副产物,开展了试验研究。重点考察臭氧-生物活性炭对水中有机物和氯化消毒副产物的去除效果,通过与常规处理出水水质的对比,探讨其去除有机物和消毒副产物的优势。结果表明,臭氧-生物活性炭是一个长期有效的去除有机物和氯化消毒副产物的控制手段。该工艺对CODMn、TOC、UV254的去除率分别为43.2%、24.0%、58.8%;对THMsFP去除率为40.1%;对三氯甲烷和三氯乙醛的去除率分别达到54.5%和70.7%。在臭氧-生物活性炭组合处理工艺中,活性炭池是去除有机物和消毒副产物的关键工艺。     

某多水源水厂不同组合工艺流程的试验研究

为了提出适合某多水源水厂新建工程的工艺,进行了5组不同流程的中试研究。结果表明,对有机物去除率最高的是活性炭滤池,COD_(Mn)和UV_(254)的去除率分别是56.8%～66.3%和70.8%～73.3%;对浊度去除最有效的是砂滤池,去除率为89.5%～97.1%,超滤出水浊度稳定在0.11～0.12NTU;对臭味物质2-MIB的去除中,活性炭滤池发挥了至关重要的作用,预臭氧对2-MIB也有较好的去除效果,去除率为52.5%。"预臭氧-常规工艺-臭氧活性炭-超滤"流程与不投加前后臭氧的"常规工艺-活性炭-超滤"流程对污染物的去除规律类似。"砂滤-炭滤""炭滤-砂滤"和"砂滤-超滤"3组流程对比显示各自均存在一些不足。综合考虑"预臭氧-常规工艺-臭氧活性炭-超滤"是最适合该新建水厂的工艺流程。     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

Serial discontinuities in a Rocky mountain river. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。