水对公路工程的危害及公路建设对水环境的影响

水对公路的路基、路面、隧道等结构都会产生危害，而公路建设也会对沿线的地下水环境产生影响。进行公路排水对提高使用道路的寿命和服务质量有积极的作用，但也应考虑公路建设对地下水和地表水环境的影响。     

西藏河谷地区荒漠化综合整治 --以日喀则市江当为例

在西藏现有的2047万hm^2的沙漠化土地中，对人类生产和生活危害最大的是藏南宽谷地区的沙漠化土地。日喀则江当宽谷中游，农业生产历史悠久，人口稠密，土地沙漠化严重。在深入分析当地自然环境和沙漠化灾害特征的基础上，提出将沙漠化土地的防治与利用相结合，根据立地条件的不同，以生物措施为主(农田防护林、防风固沙造林、流沙固定)，辅以水利工程措施，对荒漠化土地开展综合整治研究。西藏自治区林业局按照本研究防治措施进行工程施工，其中，农田防护林459hm^2，防风固沙造林3025hm^2，流沙固定399．5hm^2，修建干渠17．6km。这些工程措施布局合理，确保了各项防治措施的配套和高效发挥作用，不仅有效地治理了荒漠化土地，改善了当地的生态环境，同时，也带来巨大的经济和社会效益，有力地保障了社会经济的可持续发展。     

Examination of Critical Factors Related to Summer Chlorophyll a Concentration in the Sueo Dam Reservoir, Republic of Korea

This study examined critical factors related to the short-term variation of algae growth in reservoirs during the summer. To this end, statistical tests were carried out at a small dam reservoir to determine how chemical factors (e.g., nutrient concentrations) and physical factors (e.g., theoretical and relative residence times, temperature) influenced the chlorophyll a (Chl-a) concentration. Statistical tests revealed that, although phosphorus (P) concentration was significant for Chl-a, residence time had much stronger relationship to Chl-a concentration than chemical factors. In addition, the study verified that relative residence time (RRT) best explained the relation of water status to algae growth. RRT was found to be useful in identifying water status related to the summer algae bloom. Finally, this study raised the possibility of inhibiting summer algae growth by operating dam reservoirs moderately. These findings need to be seriously considered when reservoir operators establish effective strategies for water quality management in summer.     

东北地区春旱对春玉米幼苗长势的影响指标和模式

春旱对春玉米幼苗长势影响田间试验分3个播种期(温度处理)和4个土壤水分胁迫处理。结果表明,在东北中部玉米主产区,玉米幼苗长势好坏主要取决于水分。玉米幼苗长势(叶龄、生物量和株高)与春季土壤湿度和土壤累积有效水量的关系模式均为二次函数。干旱胁迫降低玉米苗期生叶速度和植株高度,减轻生物量,严重抑制幼苗营养生长。玉米春旱的指标是:W在18%～19%之间,或H在45～54mm之间为轻旱;17%～18%或40～45mm为中旱;17%以下或少于40mm为严重干旱。     

Perspectives on policy framework for trans-boundary water quality management in China

In river basins that cross jurisdictional boundaries, water quality degradation has become a crucial problem and results in intensive competition among water users, especially in developing countries. Under this situation, implementing water quality management and control across jurisdictional boundaries can strengthen watershed pollution controls, and prevent pollution from being passed on and promote active pollution control within the related jurisdictional regions. This study examined the limitations of the current trans-boundary water quality management system in China and reviewed the planning and implementation of two pilot integrated trans-boundary water management systems established in the Jiangsu and Zhejiang provinces. Based on our findings, we proposed a new policy framework for trans-boundary water quality management. As a first step toward integrated watershed management in China, this policy framework can help assess the actual water pollution status of various regions and serve as a basis for an integrated watershed management system. The framework can be easily applied in other countries with trans-boundary water pollution issues, particularly in the context of developing countries.     

发电机定子冷却水水质超标事故分析

针对六盘山热电厂1号机组发电机定子冷却水水质超标事件,进行原因分析,制定相应的防范及整改措施。分析结果表明:造成此次定子冷却水水质超标事件的主要原因为城市中水水质超标,导致水处理系统酸碱使用量增加,碱液储量不足,除盐系统失效,最终使定子冷却水水质无法控制,造成超标。     

Simultaneous Removal of Nitrate and Natural Organic Matter from Drinking Water Using a Hybrid Heterotrophic/Autotrophic/Biological Activated Carbon Bioreactor

Simultaneous removal of nitrate ([Formula: see text]) and natural organic matter (NOM) from drinking water using a hybrid heterotrophic/autotrophic/BAC bioreactor (HHABB) was studied in continuous mode. The HHABB consisted of three compartments: ethanol heterotrophic part, sulfur autotrophic part, and biological activated carbon (BAC)-part (including anoxic and aerobic sections). Experiments were performed with [Formula: see text] concentration 30?mg N/L, [Formula: see text] loading rate 0.72?kg N/m(3)/d, C?:?N ratio 0.53, and three concentrations of NOM (0.6, 2.6, and 5.7?mg C/L). Overall denitrification rate and efficiency of the HHABB were not affected by NOM concentration and were in the suitable ranges of 0.69-0.70?kg N/m(3)/d and 96.0%-97.7%, respectively. NOM removal at concentration 0.6?mg C/L was not efficient because of organic carbon replacement as soluble microbial products. At higher NOM concentrations, total NOM removal efficiencies were 55%-65%, 55%-70%, and 55%-65% for dissolved organic carbon, trihalomethane formation potential, and UV absorbance at 254?nm (UV(254)), respectively. The more efficient compartments of the HHABB for the removal of NOM were the ethanol heterotrophic phase and aerobic BAC-phase. The efficiency of the HHABB in the removal of NOM was considerable, and the effluent dissolved organic carbon and trihalomethane formation potential concentrations were relatively low. This study indicated that the HHABB without the anoxic BAC-phase could be a feasible alternative for simultaneous removal of [Formula: see text] and NOM from drinking water at full scale.     

Public perception of drought and climate change in southeast England

Droughts occur as a natural feature of many climates. Several southern areas of the UK experienced water stress during 2004–2006 because of low water availability and high water demand. Climate change scenarios suggest that drought frequency could increase here in the future. This will increase the competition for water across all sectors. Understanding people's perceptions of drought and climate change is likely to be an important factor for sustainable water management by pointing to barriers to behavioural change. A mixed methodology study using questionnaires and focus groups was conducted in the Anglian and southern regions of the UK to explore public perceptions of drought and climate change. Respondents attributed the 2004–2006 regional drought to lower than average rainfall. Water-intensive lifestyles, a growth in population, increasing housing developments, leaking pipes and the privatization of water companies were also implicated. The majority of respondents claimed to change their behaviour to conserve water during 2006. Regarding the future, and under a number of different scenarios, people were more inclined to accept restrictions than agree to pay more to ensure the supply of water. They were concerned about climate change and recognized that more frequent water shortages may be one of the impacts, but this concern did not necessarily translate into action. Barriers to engagement with climate change and water-efficient behaviour included a lack of accessible information, a lack of knowledge regarding the integration of environmental spheres, a lack of resources, and a perceived lack of institutional engagement. The barriers identified appear to pose a major challenge to successful adaptation to climate change.     

Environmental Health and the 1991 Bangladesh Cyclone

A brief post-disaster study was undertaken soon after the cyclone of 1991 in Bangladesh to make a preliminary assessment of existing environmental health conditions. Eighty affected people and 26 relief personnel from the affected areas were interviewed. Faecal coliform counts, salinity conductivity and pH values were determined for 43 water samples from tubewells and ponds. The quality of 32 samples of water purifying tablets was also tested.
Water scarcity was acute, especially water used for washing and personal hygiene. The situation was made worse by the fact that the surface water sources (ponds) which were commonly used for domestic purposes other than drinking were flooded, highly contaminated and regarded as unusable. The user load on existing tubewells doubled, indicating a significantly increased demand for the tubewell water which is commonly used for drinking purposes only. The majority (63 per cent) of the water purifying tablets were found to have lost potency. Sanitation was very poor in households as well as in field clinics and shelters. Most people, including relief personnel, lacked environmental health knowledge. Suggestions regarding immediate preparations for disaster relief include: restoring water systems (tubewells and ponds), training courses for relief personnel, standardizing of water purifying tablets, promoting appropriate water use and its treatment, maintaining sanitation in clinics and shelters and improving the skills and resources of local people to enable them to cope with the situation.     

淮河流域旱涝易发区农田的陆气相互作用——CO_2通量、能量交换和水汽输送的季节变化特征

利用淮河流域旱涝易发区的安徽省寿县农田下垫面陆气相互作用观测试验资料,重点分析观测期内CO2通量、能量交换和水汽输送的季节变化,并讨论了与此有关的辐射分量通量、下垫面反射率、波恩比、能量闭合守恒、土壤温度和土壤湿度的季节变化。结果表明:CO2通量、能量分配受地表农作物长势影响明显,其中,水稻灌浆、成熟期,被稻田吸收的CO2通量最大可超过2 mg.m-2.s-1,潜热通量达到正的极大值。稻田光合作用最旺盛时期吸收的CO2通量和释放的潜热通量均大于小麦田光合作用最旺盛时期的对应量。较大土壤热通量对应于较低的土壤水含量。试验观测期的下垫面平均反射率为0.14。作物生长期,稻田表面潜热是下垫面吸收能量的主要消费者,小麦田表面潜热和感热相当。能量闭合率ε的变化范围为0.4~1。     

洪涝灾害后区域水环境中污染物迁移转化控制研究

洪涝灾害发生后,大量洪水会携带污水与各类垃圾,以及形成的径流冲刷,将导致水体中的污染物明显增加,严重破坏生态环境。以多环芳烃为例进行了洪涝灾害后区域水环境中污染物迁移转化控制研究,分析污染物吸附机理,分别建立吸附动力学方程与等温线模型,确定污染物在挥发去除作用中的速度,计算挥发损失程度;并结合对流作用、分子扩散、放射性衰变等方面的影响,构建迁移数学模型;以海南省三亚市为例,利用迁移模型对多环芳烃的控制方案进行筛选与优化,通过格朗日乘数法计算多环芳烃的控制率。研究结果表明,多环芳烃控制方案结合了多目标组合优化,使控制方案更符合实际情况,从而最大程度上减少洪涝灾害对水体环境的污染。     

敞开式循环冷却水水质的监督控制

针对宁夏大坝发电有限责任公司循环冷却水补水水质随季节变化大,胶球收球率偏低、浓缩倍率控制不稳定等问题,对胶球收球率,循环冷却水浓缩倍率及补水方式进行分析,提出改进措施,以确保凝汽器的安全经济运行。应用结果表明:用钙稳定度指标控制药剂的加入量并对胶球清洗装置进行改造,可很好控制敞开式循环冷却水水质。     

历史时期中国热带的气候波动与自然灾害

根据沉积、考古、热带动物分布及相关史料得出,中国热带地区历史时期(周代至清代)的气候波动有5个冷期及其间的4个暖期.唐宋以后,自然灾害加剧,其中尤以冷期为甚.中国北方晋至南北朝、南宋、明末的3次人口南迁,对热带地区的人口增长和资源开发有深刻影响.热带地区自然条件相对优越而稳定,自然灾害比北方轻,而且国土开发较晚,经济发展滞后,因而环境状况的变化不如北方剧烈.秦汉时期环境好,唐宋时期环境尚好,明清时期则环境渐趋恶化.     

汤逊湖水体叶绿素浓度遥感估测研究

内陆水体叶绿素浓度遥感监测的各种经验模型在模型的方法和参数上都有一定的时空限制。为了实现武汉汤逊湖叶绿素浓度的遥感监测,利用同步实测的光谱数据和水质数据进行了该湖泊叶绿素浓度的遥感定量反演研究。首先分析了汤逊湖水体的反射率光谱曲线;其次通过相关分析的方法,发现了汤逊湖水体反射率在单波段法、一阶微分法和比值法建模中的最优波段或组合,并进行了一元线性建模;最后对3种模型的反演精度进行了比较分析。结果表明,对于汤逊湖叶绿素浓度遥感反演,一阶微分法和比值法优于单波段法,一阶微分法的最优波段在446.9 nm附近,比值法的最优波段组合为R861.1/R865.7,二者回归R2都在0.86以上。本项研究可为汤逊湖叶绿素浓度的遥感估测提供了参考。     

渭河水环境问题与治理对策

对渭河水环境的状况进行了讨论 ,认为近年来 ,渭河径流量减少、水质污染、河床淤积抬升、地下水危害加剧。据此 ,提出了水环境治理的对策 ,应节、蓄、引并举 ,大搞生态环境建设 ,加强水污染防治 ,减沙清淤 ,固堤防洪 ,变害为利     

深埋地下结构工程环境水水质异常成因分析

分析了某抽水蓄能电站地下厂房硐室群开挖引起环境水水质异常的成因。对工程区进行大范围的环境水pH值检测和代表性渗水部位水样的成分分析后发现,环境水的pH值、SO42-含量和总铁含量特征在一些部位发生了明显改变:水质呈强酸性、SO42-含量和总铁含量高且分布不均匀。结合岩石成分分析和现场黄铁矿矿化点的调查,认为该抽水蓄能电站地下厂房硐室群环境水水质的异常是由地层中不均匀分布的黄铁矿矿化点在开放条件下的氧化造成的,与厂房区锚孔中使用的化学充填材料无关。鉴于当前还没有有效防止强酸性腐蚀的材料,建议加强勘察期间水文地质条件特别是深部水文地质条件的研究,及早掌握和预测深部结构工程开挖、运行过程中由于环境条件改变可能导致的水质改变,以便采取预防措施。     

水质灾害成因及控制对策

水质灾害作为灾害的一种具体表现形式,和其它灾害一样能给人类生活带来巨大的负面影响.为规避灾害风险,必须加强对水质灾害成因的研究.详细分析了水质灾害的成因,考察了形成水质灾害的致灾机制;提出了水质灾害的预防措施和灾后的控制策略,同时提出了预测水质灾害的工作方法;最后,总结了今后应该深人研究的重点.     

河南省小麦白粉病流行原因和减灾对策

本文阐述了河南省小麦白粉病流行成灾的特点、原因和发展趋势,指出今后数年内小麦白粉病的发生仍将严重,并提出了短期和长期减灾对策建议.     

空冷机组运行初期如何降低汽水系统的硅含量

为了保证对空冷发电机组的水汽系统在机组运行初期硅含量监督指标的控制,对影响水汽中SiO₂含量的因素进行分析,提出洗硅的有效方法和措施。应用结果表明:采用洗硅、投运前冲洗、合理的凝结水精处理以及调节pH值等控制手段,可有效改善并解决水汽系统硅含量长期超标的问题,保证机组合格的水汽品质。     

Comparison of Advection-Diffusion Models and Neural Networks for Prediction of Advanced Water Treatment Effluent

An artificial neural network (ANN) can help in the prediction of advanced water treatment effluent and thus facilitate design practices. In this study, sets of 225 experimental data were obtained from a wastewater treatment process for the removal of phosphorus using oven-dried alum residuals in fixed-bed adsorbers. Five input variables (pH, initial phosphorus concentration, wastewater flow rate, porosity, and time) were used to test the efficiency of phosphorus removal at different times, and ANNs were then used to predict the effluent phosphorus concentration. Results of experiments that were conducted for different values of the input parameters made up the data used to train and test a multilayer perceptron using the back-propagation algorithm of the ANN. Values predicted by the ANN and the experimentally measured values were compared, and the accuracy of the ANN was evaluated. When ANN results were compared to the experimental results, it was concluded that the ANN results were accurate, especially during conditions of high phosphorus concentration. While the ANN model was able to predict the breakthrough point with good accuracy, the conventional advection-diffusion equation was not as accurate. A parametric study conducted to examine the effect of the initial pH and initial phosphorus concentration on the effluent phosphorus concentration at different times showed that lower influent pH values are the most suitable for this advanced treatment system.