The inluence of the structure and chemical nature of the surface of membranes on their functional characteristics in pressure-driven purification of artesian waters

The article has investigated the impact of the structure and chemical nature of the surface of membranes on their functional characteristics in pressure-driven processes of purifying artesian waters with an increased carbonate hardness in the absence and with an addition of inhibitors of sludge formation of various types. It is shown that in the absence of the inhibitor the sediment formation intensity is determined by two factors—chemical nature and initial structure of membranes. After the introduction to the water of the inhibitor (independent of its type) sludge formation is slowed down due to a decrease of the impact of both factors. Data were obtained, which indicate a different mechanism of inhibition of sludge formation of the polymers used.     

自流井井房设计

介绍了自流井井房设计中的流量确定，机组布置、管路设计的注意事项，重点论述了防止自流井井房被淹的特殊技术措施，提出钭管路系统与设备分两层布置，有效解决了溢流水问题。     

高承压水地区钻孔灌注桩成孔与灌注施工技术

结合工程实例，介绍了高承压水地区钻孔桩的成孔、灌注施工工艺，提出了高承压水地区桩基施工应注意的事项，对类似工程有一定的借鉴作用。     

防静电环氧自流平地坪施工技术

防静电环氧自流平地坪具有整体性好、无接缝、表面光洁、防尘、防滑、防腐、耐磨、耐压、耐冲击、防静电、易清洁等特点。以深圳市乐天品特涂饰有限公司与德国百利加公司合作施工的IIPC长城国际信息厂房防静电环氧自流平地坪为例，介绍防静电环氧自流平地坪施工的基面处理、材料系统及施工方法等。     

南岸干渠察县自流灌区管材的选取

介绍了供水管材的种类,对管材的综合性能进行了比较,探讨了管材的选择原则,并提出了选择管材的建议,指出只有对运行工况环境条件、施工条件、经济条件等多种因素进行比较和分析,才能最终合理确定选用何种管材。     

自流井群溢泛区的治理施工工艺研究

针对太原市清徐县平泉的自流井群水文地质条件进行了分析,分别阐述了对该自流井群溢泛区施工治理的必要性及具体方案,并指出施工过程中应注意事项及质量检查要点,对今后同类治理工程具有一定的指导意义。     

高承压水地层开挖基坑底板隆起稳定性分析

在分析高承压水地层基坑开挖时基坑底板破坏机理的基础上,利用塑性极限分析中的塑性铰线法提出了一种计算抗承压水基坑底板临界厚度的方法,其优点是能综合考虑基坑底板的几何尺寸、底板土层的破坏强度及破坏形式等因素对底板稳定性的影响。在7个工程实例的计算中,该法与传统基坑底板稳定性分析方法以及数值模拟方法进行了比较,结果表明本文方法明显优于传统的稳定性分析方法,能较真实地反映基坑底板抗隆起的稳定性。     

滇中红层地区自流井成因分析

本文对在云南抗旱打井突击找水行动中打出的6眼自流井进行了典型找水经验介绍并简单分析了其成因类型,总结出红层地区找水要在综合收集资料的基础上,通过实地调查和高密度电法勘查,选择地貌汇水有利部位,地层构造的富水地段综合确定井位,选用适宜的施工方法是提高成井率的有效途径.根据自流井的特点提出了开发利用建议.     

基坑开挖和减压降水引起周边民宅沉降的控制措施

使用悬挂式止水帷幕的基坑进行减压降水会使周边地层产生固结沉降,从而加剧因基坑开挖引起的本已较为严重的建筑物沉降。因此,对于此类基坑周边采用天然地基的老旧建筑物的保护需多种措施联合使用。结合基坑工程实例,采用加强围护结构设计、对承压含水层进行地下水回灌以及采用信息化施工等多种手段,收到了良好的效果,可供类似工程借鉴。     

基坑减压降水对不同基础型式建筑物沉降的影响

使用悬挂式止水帷幕的基坑进行减压降水会使周边地层产生固结,从而造成基坑周围大范围的建筑物沉降。采用不同基础型式的建筑物由于将其自重荷载和使用荷载传递到地基土层的方式不同,在临近的基坑进行减压降水时产生的沉降也有较大的差异。结合基坑工程实例,对基坑减压降水引起周围不同基础型式建筑物的沉降发展规律进行了实测研究,结果表明,采用桩基础的房屋对于抵抗减压降水引起的沉降效果最为显著,天然地基的房屋沉降量较大,是减压降水中需要重点保护的对象。     

Natural radionuclides in mineral waters

Concentration levels of natural radionuclides in mineral waters have been studied in several European countries. In the Federal Republic of Germany in recent years a nationwide investigation was carried out by several institutions.The concentrations of ²²⁶Ra, uranium isotopes, ²¹⁰Pb and ²¹⁰Po found are similar to those in other European countries. While for adults the health risk from drinking mineral water is comparable to the risk from terrestrial radiation, special consideration has to be given to the risk of infants when mineral water is used for preparing their food.     

动态承压水作用下深基坑底部弱透水层的出逸比降解析研究

根据深大基坑坑底弱透水层的一维越流模型,求解了承压水头变化引起的坑底弱透水层中的超静孔隙水压力和出逸比降的解析表达式。当坑底土层渗透系数较大时,出逸比降计算结果与传统方法的出逸比降求解结果一致,验证了出逸比降解析解的正确性。基于出逸比降解析解,分析了动态承压水作用下坑底出逸比降的变化规律和影响因素。结果表明:当基坑坑底弱透水层厚度一定时,土体渗透系数、压缩模量或承压水头波动周期越大,出逸比降波动越明显,幅值越大,相位差越小;出逸比降影响因素可通过与土体渗透系数和压缩模量正相关,与承压水头波动的角频率和弱透水层厚度的平方负相关的无量纲因子统一表示。最后通过工程实例表明,对于坑底弱透水层渗透系数较小的情况,降承压水头引起的出逸比降减小幅度不大并存在明显滞后性,对基坑的抗渗流稳定性具有不利影响。     

The chemical composition of highway drainage waters IV. Alkyllead compounds in runoff waters

Alkyllead compounds have been analysed in road drainage water samples collected during seven storm events using a sensitive gas chromatography-atomic absorption technique. The most commonly observed alkyllead species were tetraethyllead, triethyllead and trimethyllead. Similar compounds were also observed in rainwater collected at the site, but not in road surface dust or bottom sediment from the drainage channel. In all samples analysed the concentration of alkyllead was < 5% of the dissolved (< 0.45 μm) inorganic lead. It is postulated that washout of alkyllead from the atmosphere is the major source of alkyllead compounds in the drainage waters analysed. Alkyllead species were also identified in rainwater collected at other sites.     

Halonitromethane formation potentials in drinking waters

Halonitromethanes (HNMs) are highly cyto- and genotoxic nitrogenous disinfection by-products (DBPs) that have been detected in some water distribution systems. In this study, a systematic investigation was conducted to examine the formation potential of HNMs in drinking waters under different oxidation conditions. Formation potential tests of samples obtained from various drinking water sources showed that ozonation-chlorination produced the highest HNM yields followed by in the order of chlorination, ozonation-chloramination, and chloramination. Similar or higher HNM yields were observed in the treated waters (i.e., after conventional water treatment) than in the raw waters, indicating that hydrophilic natural organic matter (NOM) components that are not effectively removed by conventional treatment processes are likely the main precursors of HNMs. This was further confirmed by examining HNM formation potentials of NOM fractions obtained with resin fractionation. Hydrophilic NOM fractions (HPI) showed significantly higher HNM yields than hydrophobic (HPO) and transphilic (TPH) fractions. The correlation analysis of HNM formation potentials during ozonation-chlorination with various water quality parameters showed the best correlation between the HNM yields and the ratio of dissolved organic carbon to dissolved organic nitrogen concentrations in the water samples tested.     

Trace metal species in fresh waters

A recently proposed trace metal speciation scheme was applied to the determination of the chemical forms of copper, lead, cadmium and zinc in four natural fresh waters and a tap water. Studies were also made on the reliability of the technique, and of the effect of various methods of storage on the speciation results. The measurements showed that (a) copper in the river and reservoir samples was associated mainly with organic matter, probably organic colloids; (b) lead was divided between stable inorganic and organic forms, but one particular inorganic lead species predominated; (c) cadmium existed almost entirely as labile ionic forms; (d) zinc was divided between labile ionic species and a stable inorganic form; very little zinc was associated with organic colloids, and (e) the trace metals were not combined with inorganic colloids. Samples stored in polyethylene containers for over three weeks at 25°C or 4°C showed little change in either total metal concentration or metal speciation. Freezing, however, caused some irreversible changes.     

Modelling diatom growth in turbulent waters

Algal models used as tools in the management of algal blooms may be inaccurate because representation of mixing processes is often oversimplified. A testable 3-D algal model for prediction of algal growth in turbulent surface waters was developed based on the Eulerian water quality model, HYDRO-3D. Out-door mesocosm experiments on the growth of the diatom Skeletonema costatum showed no evidence that diatom growth is significantly affected by light/dark fluctuations brought about by turbulent mixing, and no direct effects of turbulence on phytoplankton physiology were required in the algal model. The algal model was successfully calibrated and validated against mesocosm data and field data from Poplar Dock, London Docklands. Application of the model gave credible results for the hypothetical growth of S. costatum in Poplar Dock under a wide range of wind speeds and surface irradiances. However, differences between the results of a full 3-D simulation and a simplified 1-D representation of Poplar Dock were minimal, and no clear conclusions could be drawn on the superiority of 3-D models over 1-D models for simulation of complex flows in natural water bodies.     

Modeling copper partitioning in surface waters

Suspended particulate matter from the surface waters of the Susquehanna, Christina and Brandywine Rivers was collected by tangential flow filtration to study copper partitioning. Copper adsorption increased with an increase of suspended particles and decreased with low pH values or with an increase of dissolved organic matter. Effects of particulate organic matter on copper distribution between suspended particulate and solution phases were studied using modified aluminum oxide. An increase of particulate organic matter enhanced copper adsorption. Copper adsorption per mass of particulate organic carbon was similar for the different sources of suspended particles. A model, based on copper adsorption on particles and complexation with dissolved organic matter, was developed to assess copper partition coefficient as a function of the easily measurable water quality parameters: pH, alkalinity, dissolved organic carbon and particulate organic matter. The partitioning model was calibrated on pH edge data using suspended particles collected from the three rivers. The model was verified using partitioning data as a function of dissolved organic matter. The model adequately describes the system containing natural suspended solids collected from the surface waters.     

Atomic-absorption determination of aluminum in waters

The article investigated the impact of sodium salts of acylhydrazones of pyroracemic acid as modifiers of the matrix on the electrothermal atomic-absorption determination of aluminum. The technique has been developed for determination of aluminum in fresh waters with the detection limit 0.005 m/dm³.