以T_(max)为依据控制某输气站场化粪池出水悬浮物浓度

某输气站场的生活污水处理设备频繁故障,通过分析确定主要原因为其前段处理单元(化粪池)清掏周期过长,下层污泥流入生活污水处理设备,导致设备故障。并推导化粪池最大清掏周期(Tmax),指导实际运行,控制化粪池出水悬浮物浓度,提高污水处理设备运行稳定性。     

人工湿地对化粪池出水净化效果的研究

通过在同种基质上种植相同数目的芦苇,研究了垂直流人工湿地对化粪池出水的净化效果以及不同水力停留时间对污水净化效果的影响。结果表明,同种填料、不同水力停留时间对污水中TP、NH3-N、COD的净化效果不同。由于芦苇根系和微生物的吸收与分解作用以及基质的吸附作用,种植芦苇的人工湿地的出水水质要比没种芦苇的好。     

西安市第五污水处理厂一级A提标改造措施分析

2013年,西安市污水处理厂出水将达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A标准,分析了西安市第五污水处理厂工艺特征及运行现状,对污水处理厂工艺优化与提标改造进行研究,认为通过降低初沉池水力停留时间以减少有机物过多流失、量化分段进水流量实现碳源优化配置等改造措施及优化控制生化池溶解氧、污泥回流比、污泥龄等工况,可强化系统脱氮除磷效果,提高系统出水水质,TN、TP、COD等指标基本可达到一级A标准。但出水SS过高仍制约了污水处理厂的一级A全面达标,需对出水进行进一步的终端控制。项目研究为污水处理厂后期的提标改造工程提供运行参数及技术指导。     

城市污水处理厂运行除磷效果影响因素分析

针对西安市第四污水处理厂倒置A2/O工艺实际运行除磷效果差、出水TP不能达标排放的问题,通过监测污水处理厂实际进出水水质和生化反应池运行参数,分析除磷效果差的主要原因,并研究其解决措施,寻求最优的运行参数和工程改造措施,提出优化厌氧区水力停留时间、强化污泥处理系统污泥水的处理,以及启动污水处理厂已建成的化学除磷系统等措施。     

制药行业废水改造工程实例

山东某制药企业污水处理工程主体生化采用AO工艺,在实际运行过程中,污泥膨胀严重,出水COD、总氮长期不达标.改造工程优化AO工艺为多级AO,并增加弹性填料.运行结果表明,对COD、总氮的去除率分别达到98.9％、95.2％,出水水质稳定达到园区污水接管标准.     

无锡某污水处理厂升级改造前后进水水质及污泥产量分析

无锡某污水处理厂升级改造前后进水水质及特征均产生较大变化,导致污水处理厂脱氮除磷可利用的碳源减少,分析表明,污水处理厂进水水质指标间均存在较好的线性相关性。一级A排放标准对氮、磷均提出了更高的要求,而其中总氮达标是最大的难题,现有进水水质条件下,化学除磷和投加外加碳源是保证氮、磷达标排放的有效措施,这两种措施均会导致污泥产量的增加。污水处理厂应根据进水水质和季节对处理工艺及运行参数进行优化调整,使得出水水质稳定达标,同时降低能耗和污泥产量。     

新疆阿克苏污水处理厂的设计及运行

新疆阿克苏污水处理厂首次采用水解-交替式内循环活性污泥工艺(AICS工艺)处理城市污水。水解池停留时间为2.6 h,好氧AICS工艺停留时间为5.3 h,运行周期为6 h,污泥负荷采用0.34 kgBOD/(kgMLSS·d)。实际运行结果表明,出水COD,BOD和SS均达到国家一级排放标准。其工程投资成本仅为669元/m3,处理费用为0.34元/m3。     

新疆生产建设兵团某工业园区废水处理厂设计

新疆生产建设兵团某工业园区废水处理厂进水由生活污水和工业废水组成,出水水质要求达到《城镇污水处理厂污染物排放标准》一级A排放标准(GB 18918-2002)。工程废水处理主体工艺采用粗格栅及进水泵房-气浮沉淀池-水解酸化池-A~2/O反应池-MBR反应池对进厂废水进行处理,污泥处理采用污泥浓缩池-厢式隔膜压滤机工艺。一期建设规模为3万m~3/d。介绍了工程设计进出水水质指标的确定、主要构筑物的工艺设计参数以及工艺设计特点,并对运营后进出水水质进行了分析。     

天津市咸阳路污水处理厂工艺设计及特点分析

天津市咸阳路污水处理厂采用A/O厌氧除磷工艺,近期建设规模45万m3/d,最大处理能力58.5万m3/d,是集中了污水、污泥处理,回用水处理,污泥干化后处理和填埋处置的综合型、环保型排水工程。介绍了该工程的工艺流程、进出水水质指标、主要构筑物的设计参数以及工艺特点。目前污水处理厂出水已达到《污水综合排放标准》(GB8978—1996)二级排放标准,污泥转鼓干化也已进入试运行阶段。     

宁波北区污水处理厂二期工程设计及运行效果

宁波北区污水处理厂二期工程设计出水水质执行《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A标准,从2017年1~6月运行数据看,处理效果较好,出水水质稳定且优于设计值,脱水后污泥含水率不高于60%。详细介绍了工程的设计情况及特点,并总结了设计经验。     

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。     

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。     

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.