Long-term hydraulic and pollution retention performance of infiltration systems.

Infiltration techniques are now widely used to manage stormwater in urban areas. These techniques are used and recognized around the world for their many advantages, such as decreasing stormwater flow in sewer systems and recharging groundwater. But numerous cases of infiltration devices that failed after a few years of operation are still being reported. This study, which is based on site-monitoring of operational infiltration systems, is part of the Field Observatory for Urban Water Management (OTHU). The main goals of this study are to improve knowledge of long-term hydraulic behaviour, especially as concerns the clogging speed and the quality of the runoff. This article will present the site, the monitoring process and the model that will be used to assess the hydraulic behaviour. First results of the calibration of the model show that the model is able to assess the hydraulic behaviour of the basin when it is clogged (average value of hydraulic resistance 17.1 h) and when it has been scraped (hydraulic resistance less than 3.8 h). However, further data are needed in order to validate the model. We also show that the experimental setup is well designed to assess the water volume and the sediment brought to the basin with low uncertainties.     

The hydraulic capacity of deteriorating sewer systems.

Sewer and wastewater systems suffer from insufficient capacity, construction flaws and pipe deterioration. Consequences are structural failures, local floods, surface erosion and pollution of receiving waters bodies. European cities spend in the order of five billion Euro per year for wastewater network rehabilitation. This amount is estimated to increase due to network ageing. The project CARE-S (Computer Aided RE-habilitation of Sewer Networks) deals with sewer and storm water networks. The final project goal is to develop integrated software, which provides the most cost-efficient system of maintenance, repair and rehabilitation of sewer networks. Decisions on investments in rehabilitation often have to be made with uncertain information about the structural condition and the hydraulic performance of a sewer system. Because of this, decision-making involves considerable risks. This paper presents the results of research focused on the study of hydraulic effects caused by failures due to temporal decline of sewer systems. Hydraulic simulations are usually carried out by running commercial models that apply, as input, default values of parameters that strongly influence results. Using CCTV inspections information as dataset to catalogue principal types of failures affecting pipes, a 3D model was used to evaluate their hydraulic consequences. The translation of failures effects in parameters values producing the same hydraulic conditions caused by failures was carried out through the comparison of laboratory experiences and 3D simulations results. Those parameters could be the input of 1D commercial models instead of the default values commonly inserted.     

二维强非均质含水层中渗透系数空间变异对污染物迁移的影响

对于强非均质介质,渗透系数的对数lnK的空间分布可表征为其增量遵从Levy稳定分布的非平稳随机场。本文利用改进的连续随机增量方法生成含水层lnK增量具有Levy稳定分布的统计特征的随机场;采用Monte-Carlo数值实验方法并结合MODFLOW与MT3DMS分别模拟研究区域内水流和溶质迁移过程,分析渗透系数强变异性对污染物浓度空间矩及宏观弥散的影响。结果表明:Levy指数α决定lnK的空间分布形状,宽度参数C则影响lnK的取值范围;污染物的质心位置与C、α的大小无关;C越大、α越小,污染物形状越不规则,污染物的扩散范围越大;且α越小,污染物具有明显的拖尾现象;纵向宏观弥散度随时间呈幂函数递增趋势。     

高低水头双套纯机械过速保护装置的应用

介绍了TURAB纯机械过速保护装置在锦屏一级水电站的应用状况。由于水电站运行水头的变幅高达87 m,致使原单套装置难以同时满足水头全覆盖和保护不误动。在这种情况下,若保护动作的定值按照高水头来整定,则在低水头段运行时,会因机组飞逸转速过小而难以触发保护动作;若按照低水头来整定,那么在高水头段运行时,机组在甩满负荷后的最大转速又将会误触发保护动作。经过分析研究,研制出了有效的解决措施,即划分高低水头段,利用双套纯机械过速保护装置以及电控液动切换阀,分别进行保护配置的方案,并对该方案的可行性进行了论证。可为同类工程的设计和改造提供借鉴。     

二维强非均质含水层中水力传导度空间变异对污染物迁移的影响

对于介质的非均质性相对较小的情况，可将水力传导度对数(lnK) 的空间分布概化为正态分布的统计均匀随机场。而对于强非均质介质，lnK的空间分布可表征为其增量遵从Levy稳定分布的非平稳随机场。本研究假设二维承压含水层内面积为128m x 128 m的研究区域中,在(10m,64m)处瞬时注入浓度为1000 mg/L的污染物：利用改进的连续随机增加（successive random additional, SRA) 方法生成含水层lnK增量具有Levy稳定分布的统计特征的随机场；采用Monte-Carlo数值实验方法并结合MODFLOW与MT3DMS分别模拟研究区域内水流和溶质迁移过程，分析水力传导度强变异性对污染羽状物浓度空间矩及宏观弥散的影响。结果表明：Levy指数a决定lnK的空间分布形状，宽度参数C则影响lnK的取值范围；污染羽的质心位置(一阶矩)与C、a的大小无关；C越大、a 越小，污染羽形状越不规则，污染羽状物的扩散范围(二阶矩)越大；且a 越小，污染羽状物具有明显的拖尾现象；纵向宏观弥散度随时间呈幂函数递增趋势。     

常州市某区域地下水渗入量的估算

排水管道中地下水渗入量的指标采用单位管长的负荷(渗入系数或渗入率)来衡量,可以用m~3/(km·d)或m~3/(km·mm·d)来表示。地下水水位越高,地下水平均渗入率就越大,鉴于此,常州市某区域的渗入率分为雨季和非雨季分别进行估算,通过测定该区域管网中3.8 kmDN1 650管道在非雨季时的渗入量,并结合其他同纬度城市及临近城市的地下水渗入率数值,确定该区域渗入率,进而估算渗入量。     

Formation of mineral deposits in hydraulic ash removal systems

Selection of design schemes for the water supply (straight through, or circulating) of hydraulic ash-removal (HAR) systems for thermal electric power plants (TPP) is examined as a function of the character of mineralization of the water in a specific system. Causes are outlined for the formation of mineral deposits on equipment of the HAR system, which transports ash slurries of different types of solid fuels. The cause of the high rate of seasonal growth formation in the circulating HAR systems of TPP burning fuel with highly alkaline ash slurries is established experimentally in an example of a shale electric power plant. Measures are developed for rapid slow-down of the rate of growth formation in these systems. Measures are proposed for prevention of growth formation for other types of ash slurries. __________ Translated from élektricheskie Stantsii, No. 5, pp. 41–47, May, 2006.     

PAM对土壤入渗量和抗侵蚀能力的影响

通过试验模拟,研究了关于土壤中施加不同分子量聚丙烯酰胺（PAM）对土壤抗侵蚀能力的影响。试验结果表明PAM可以有效地增加土壤入渗率。分子量500万PAM对增加土壤入渗率效果更明显。但随着时间的推移,分子量500万PAM处理过的土壤的抗侵蚀能力减弱,而分子量由1200万PAM处理过的土壤抗侵蚀能力变化不大。PAM可以有效减少土壤侵蚀量。     

Nitrogen removal capacity of wetlands: sediment versus epiphytic biofilms.

Wetlands are important sinks for nutrients and constructed wetlands are current practice for stormwater treatment. For nitrogen, the main removal process is denitrification (microbial reduction of nitrate to nitrogen gas). The bacteria responsible for this process are mostly found in the sediments and in epiphytic biofilms growing on wetland macrophytes. This paper reports on a project which aimed at measuring denitrification potential in sediments and epiphyton in urban wetlands. This study showed that wetland sediments could support high rates of denitrification. Interestingly, the most polluted of the wetlands studied had the highest denitrification potential. The management implication from this result is that indicators of pollution, such as hydrocarbon levels, will not necessarily reflect the ability of a wetland to denitrify. Two of the wetlands were studied in more detail. Here the denitrification potential of the epiphyton on dominant macrophytes and sediments were measured. The results indicated that the potential denitrification activity of the epiphyton was comparable to those measured in the sediments. Hence, biofilms could play a significant part in removing nitrogen loads. This work contributes to a better knowledge of the functioning of wetlands. This will lead to improved design and management of wetlands used for treating stormwater.     

Monitoring, removal and risk assessment of cytostatic drugs in hospital wastewater.

Cytostatic agents are applied in cancer therapy and subsequently excreted into hospital wastewater. As these substances are known to be carcinogenic, mutagenic and toxic for reproduction, they should be removed from wastewater at their source of origin.In this study the fate and effects of the cancerostatic platinum compounds (CPC) cisplatin, carboplatin, oxaliplatin, 5-fluorouracil (5-FU) and the anthracyclines doxorubicin, daunorubicin and epirubicin were investigated in hospital wastewater. Wastewater from the in-patient treatment ward of a hospital in Vienna was collected and monitored for the occurrence of the selected drugs. A calculation model was established to spot the correlation between administered dosage and measured concentrations. To investigate the fate of the selected substances during wastewater treatment, the oncologic wastewater was treated in a pilot membrane bioreactor system (MBR) and in downstream advanced wastewater treatment processes (adsorption to activated carbon and UV-treatment). Genotoxic effects of the oncologic wastewater were assessed before and after wastewater treatment followed by a risk assessment.Monitoring concentrations of the selected cytostatics in the oncologic wastewater were in line with calculated concentrations. Due to different mechanisms (adsorption, biodegradation) in the MBR-system 5 - FU and the anthracyclines were removed < LOD, whereas CPC were removed by 60%. In parallel, genotoxic effects could be reduced significantly by the MBR-system. The risk for humans, the aquatic and terrestrial environment by hospital wastewater containing cytostatic drugs was classified as small in a preliminary risk assessment.     

Effects of leachate infiltration and desiccation cracks on hydraulic conductivity of compacted clay

Both cracks in clay liner and the complex composition of landfill leachate might have effects on the hydraulic conductivity of a compacted clay liner. In this study, the hydraulic conductivities of natural clay and bentonite-modified clay with and without desiccation cracks were measured, respectively, using three types of liquids as permeating liquid: 2 500 mg/L acetic acid solution, 0.5 mol/L Ca Cl2 solution, and tap water. When tap water was adopted as the permeating liquid, desiccation cracks resulted in increases in the average value of hydraulic conductivity: a 25-fold increase for the natural clay and a 5.7-fold increase for the bentonite-modified clay. It was also found out that the strong selfhealing capability of bentonite helped to reduce the adverse impact of cracks on hydraulic performance. In contrast to tap water, simulated leachates(acetic acid and Ca Cl2solutions) show no adverse effect on the hydraulic conductivities of natural and bentonite-modified clays. It is concluded that desiccation cracks and bentonite have more significant effects on hydraulic performance than simulated leachates.     

Measuring devices for instrument inspection of bearings and shafts in hydraulic generating sets

Measuring devices for inspection of the shafts of hydraulic generating sets is described. Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 6, June 2008, pp. 12–18.     

湾湾川水力发电厂水轮机增容改造分析

文中通过对湾湾川水力发电厂增容改造机组机型的技术经济比较分析,提出对电站改造在机型选择上应充分考虑流道偏差对性能的影响,使改造工程发挥更大的经济效益。     

兴隆枢纽泄水闸设备维修养护管理初探

为了做好泄水闸的设备管理工作,保证泄水闸的安全运行,从维修养护对象及人员组织、维修养护计划编制、维修养护管理模式三个方面进行了有益探索,形成了一套行之有效的设备管理方法。根据维修养护管理对象及其特点,进行了设备分类管理,建立了适合自身特点的维护人员组织结构,并在确定设备维修养护等级和养护项目的基础上,以设备利用率为中心编制维修计划,选用了适合自身管理特点的维修责任制度,并创造性地将制造企业管理中的全面质量管理思想和5s现场管理思想应用到泄水闸设备的维修养护管理工作中,在实践中取得了良好的效果。     

Evaluation of the purification capacity of nine portable, small-scale water purification devices.

A test was performed to evaluate the microbial and chemical purification capacity of nine portable, small-scale water purification filter devices with production capacity less than 100 L/h. The devices were tested for simultaneous removal capacity of bacteria (cultured Escherichia coli, Clostridium perfringens, Klebsiella pneumoniae and Enterobacter cloacae), enteric protozoans (formalin-stored Cryptosporidium parvum oocysts), viral markers (F-RNA bacteriophages) and microcystins produced by toxic cyanobacterial cultures. In general, the devices tested were able to remove bacterial contaminants by 3.6-6.9 log10 units from raw water. Those devices based only on filtration through pores 0.2-0.4 microm or larger failed in viral and chemical purification. Only one device, based on reverse osmosis, was capable of removing F-RNA phages at concentrations under the detection limit and microcystins by 2.5 log10. The present study emphasised the need for evaluation tests of water purification devices from the public safety and HACCP (Hazard Analysis and Critical Control Point) points of view. Simultaneous testing for various pathogenic/indicator microbes and microcystins was shown to be a useful and practical way to obtain essential data on actual purification capacity of commercial small-scale drinking-water filters.     

洪泽湖换水能力的时空分布特征EI北大核心CSCD

为研究洪泽湖换水能力的时空分布特征,基于MIKE21建立洪泽湖二维水动力模型,模拟分析了洪泽湖不同湖区的换水周期;考虑洪泽湖的流场呈现风生流和吞吐流双重特点,分析了不同季节和不同风场条件下换水周期的空间变化特征。结果表明:洪泽湖换水周期空间异质性明显,从南到北梯度递增,冬季和春季全湖平均换水周期较长,分别为75 d和60 d,秋季和夏季的全湖平均换水周期较短,分别为49 d和31 d;实际风场对洪泽湖的换水能力起到正向作用,东南风对洪泽湖的换水能力起正向作用,东北风对洪泽湖的换水能力起到抑制作用。     

改良型人工快渗系统脱氮除磷效果研究

人工快渗(CRI)系统是一种广为人知的无动力生态处理技术措施,但传统CRI系统存在对氮、磷去除率普遍较低的问题。本研究采用海绵铁、沸石、火山岩、红壤土和杂沙作为填料,构建了一个改良型CRI系统,在水力负荷为1 m~3/(m~3·d)的条件下,以实际生活污水为试验进水,进行为期20天的试验。实验结果表明,该系统在运行16天后出水TP、TN和NH_3-N浓度均趋于稳定,稳定后出水平均浓度分别为0.21 mg/L、8.38 mg/L和2.34 mg/L,能分别满足《城镇污水处理厂污染物排放标准》(GB18918-2002)一级A排放标准的0.5 mg/L、15 mg/L和5 mg/L的限值。TP、TN和NH3-N三项指标的总平均去除率为84.44%,远高于传统CRI系统的44.06%总平均去除率。该研究成果为治理农村生活污水提供了一项行之有效的生态治理技术措施。     

浅谈车辆液压转动系统故障分析与排除

全液压转向系统具有转向灵活轻便、性能稳定、故障率低、布置方便等优点。在大型载重汽车、叉车、起重运输机械、工程机械等轮式行走机械中，为了减轻驾驶员操作方向盘的体力劳动，提高车辆的转向灵活性，常采用液压助力式动力转向系统，在机械转向器上加装液压助力器。但是随之也经常产生转向失灵、转向沉重、车辆行驶时方向跑偏或发飘等问题。主要对车辆液压转向系统常见的故障原因进行了较为详细的分析，并提出了相应的排除措施，为大型载重汽车、叉车、起重运输机械、工程机械的使用保养维修提供借鉴。