Modeling of Drinking Water Distribution Networks Using Stochastic Demand

Residential water demand is one of the most difficult parameters to determine when modeling drinking water distribution networks. It has been proven to be a stochastic process that can be characterized as a series of rectangular pulses with a set intensity, duration and frequency. These parameters can be determined using stochastic models such as the Neyman-Scott Rectangular Pulse (NSRP) model. The NSRP model is based on the solution of a non-linear optimization problem. This solution involves theoretical moments that represent the synthetic demand series (equiprobable) and the observed moments (field measurements) that statistically establish the measured demand series. The NSRP model has been applied for residential demand, and the results have been published. However, this model has not been validated for a real distribution network or compared with traditional methods. The present study compared the results of synthetic stochastic demand series, which were calculated using the NSRP model, applied to the determination of pressures, flow rates and leaks; to the results obtained using traditional simulation methods, which use the curve of hourly variation in demand, and to actual pressure and flow rate measurements. The Humaya sector of Culiacan, Sinaloa, Mexico, was used as the study area.     

Classification of Drinking Water Quality Index and Identification of Significant Factors

Water pipes are considered to be one of responsible sources for the water pollution. Among these sources of water supply, the water pipes are the only source of carrying out fresh or processed water into lakes, ponds and streams etc. In Pakistan, knowledge on the condition of water pipes is scarce as deterioration of water pipes are hardly inspected due to high cost. The aim of the current research was to examine the quality of water pipelines of eight districts of South-Punjab, namely, Mianwali, Khushab, Layyah, Bhakkar, Dera Ghazi Khan, Muzaffargarh, Rajanpur and Rahim Yar Khan. Selected sampling stations were analyzed for physio-chemical parameters such as pH, Total Dissolve Solids (TDS), Sulfate (SO₄), Chlorine (Cl), Calcium (Ca), Magnesium (Mg), Hardness, Nitrate (NO₃), Fluoride (F) and Iron (Fe). The data pertaining water monitoring contain different parameters and seem difficult work for the interpretation of water quality by managing different parameters separately. For this purpose, National Sanitation Foundation Water Quality Index (NSF-WQI) was determined to communicate the quality of water in a simple form. Besides this, groups comprising of similar sampling sites based on water quality characteristics were identified using unsupervised technique. Factor Analysis (FA) has been performed for extracting the latent pollution sources that may cause the more variance in large and complex data. The calculated values of WQI from 1600 sampling stations ranging from 20.73 to 223.74 are divided into five groups; Excellent to Unsuitable class of waters with the average value 62.09 described as good limit for drinking water. Further sampling stations are divided into five optimal clusters selected with suitable k value obtained from Silhouette coefficient. Results of k-means clustering are also verified with natural groups made by WQI. Analysis of multivariate techniques showed several factors to be responsible for the water quality deterioration. It is found out from the FA that three latent factors such as organic pollution, agriculture run-off and urban land use caused 83.30 % of the total variation. Hence, water quality management and control of these latent factors are strongly recommended.     

地下饮用水水源地安全保障评价体系构建

分析阐述了饮用水水源地安全评价现状,在概括水源地安全内涵的基础上,从水质、水量、脆弱性、应急能力4个方面构建了地下饮用水水源地安全保障评价指标体系,并给出了指标选择的原则和必要性。所构建的安全保障评价指标体系可为水源地的安全保障、规划工作提供科学依据,具有实际应用价值。     

基于时间序列预测法的水利发展指标体系研究

基于时间序列分析法,采用指数曲线、修正指数曲线、对数曲线和乘幂曲线分析方法进行组合比选,根据各项指标的特点,结合国家、省级及区域宏观调控的影响以及变化趋势等因素,对甘肃水利发展规划目标指标体系6大类26项指标进行了近期2015年和远期2025年的预测研究。结果表明:采用定量分析方法,可以预测甘肃省水利发展近、远期目标与任务动态区间,为甘肃省"十二五"水利发展规划提供重要参考。     

基于EFDC模型的明湖水库水质数值模拟及预测

基于EFDC模型,以支鱼港补水闸和大尖退水闸实测流量、水质、水位为计算边界,模拟并探讨了明湖水库库区水体在静置期和交换期的水质情况。结果表明:库容较大时,库区水体水环境容量较高,水质浓度的增加幅度较小;COD浓度随水体静置时间增加的幅度较NH3-N低;在水体静置期,库区水体停留时间以27~30 d为宜;明湖水库运行期间,通过支鱼港补水闸、大尖闸与大冲闸联合调度运行,相机换水可有效保证库区水质安全。     

浅议上海饮用水水源及处理后水质

在调查和分析研究的基础上 ,对长江和黄浦江原水及其处理后水质进行了比较 ,长江原水及其常规处理后水质均明显优于黄浦江原水和出厂水。建议优先采用长江水源 ;对以黄浦江为原水的水厂的工艺流程进行改造 ,即增加生物预处理和 (或 )活性炭后处理设施。     

官厅水库饮用水源功能恢复对策

改善官厅水库水质应采取综合治理措施.对官厅水库上游流域重点企业实施治理,实现污水达标排放,在城镇污水集中地区建污水处理厂,使流入河道的水体得到净化,在水库及周边地区采取工程技术与生物生态技术相结合的措施.尽快恢复官厅水库饮用水源功能,缓解首都水资源紧缺状况.     

应用新型水质分析仪快速检测农村饮用水中的硫酸盐

针对宁夏中南部地区农村供水水质中普遍存在的硫酸盐含量检测问题,结合科研课题引进便携式水质分析仪进行快速检测,并与国标法相对照,获得满意的效果。     

颗粒活性炭在饮用水深度处理中的应用

概括介绍了国内外活性炭水处理的发展和应用情况、活性炭深度处理的机理及处理效果。针对当前水源有机污染现状和发展趋势 ,论述了采用活性炭进行饮用水深度处理的必要性 ,给出了颗粒活性炭吸附池设计的参数及要求。最后介绍了北京市城子水厂炭吸附池设计及特点。     

基于GIS的克里金法在水质影响预测中的应用

为深入研究水体污染预测系统,更好地模拟二维空间上的水污染分布,将克里金法引入二维水质模型,考虑了空间属性在不同空间位置上的变异分布,使预测模型更合乎实际,功能更全面,并实现预测过程、结果的可视化.在GIS平台上运用数据库方法,将模型预测结果和Geodatabase数据类型进行链接与转换,力求形象直观地展现天然水体的污染分布情况.     

深圳市管道直饮水系统设计探讨

结合深圳市管道直饮水的现状 ,从用水定额、净水处理工艺、管网系统、管材的选用等方面阐述了管道直饮水系统设计的一些特点及经验     

呼市自备井生活供水系统水质污染及防治对策

根据对代表性自备井供水单位的水质抽样化验结果及自来水公司供水系统的水质监测数据 ,对比分析了呼和浩特市自备井生活供水系统的水质污染现状和主要原因 ,提出了相应的防治对策。     

Ensemble Decision Tree Models Using RUSBoost for Estimating Risk of Iron Failure in Drinking Water Distribution Systems

Safe, trusted drinking water is fundamental to society. Discolouration is a key aesthetic indicator visible to customers. Investigations to understand discolouration and iron failures in water supply systems require assessment of large quantities of disparate, inconsistent, multidimensional data from multiple corporate systems. A comprehensive data matrix was assembled for a seven year period across the whole of a UK water company (serving three million people). From this a novel data driven tool for assessment of iron risk was developed based on a yearly update and ranking procedure, for a subset of the best quality data. To avoid a ‘black box’ output, and provide an element of explanatory (human readable) interpretation, classification decision trees were utilised. Due to the very limited number of iron failures, results from many weak learners were melded into one high-quality ensemble predictor using the RUSBoost algorithm which is designed for class imbalance. Results, exploring simplicity vs predictive power, indicate enough discrimination between variable relationships in the matrix to produce ensemble decision tree classification models with good accuracy for iron failure estimation at District Management Area (DMA) scale. Two model variants were explored: ‘Nowcast’ (situation at end of calendar year) and ‘Futurecast’ (predict end of next year situation from this year’s data). The Nowcast 2014 model achieved 100% True Positive Rate (TPR) and 95.3% True Negative Rate (TNR), with 3.3% of DMAs classified High Risk for un-sampled instances. The Futurecast 2014 achieved 60.5% TPR and 75.9% TNR, with 25.7% of DMAs classified High Risk for un-sampled instances. The output can be used to focus preventive measures to improve iron compliance.     

桐乡市改善自来水水质的对策初探

对桐乡市现有水厂原水、出厂水水质做出分析,提出了积极寻找优质的水源和强化水处理工艺来改善自来水水质的两个对策,并进行了多方案的技术经济比较。     

标识指数法在韩江下游主要饮用水源水质评价中的应用

介绍水质标识指数法的基本原理,并利用该方法分析评价2009年韩江下游主要饮用水源水质,给出水源保护措施。     

Drinking Water Source Monitoring Using Early Warning Systems Based on Data Mining Techniques

Water Resources Management - Improving drinking water source monitoring is crucial for efficiently managing the drinking water treatment process and ensuring the delivery of safe water. Data mining...     

浅议优质饮用水工程的设计

结合工程实例介绍了在优质饮用水系统中用水量标准的确定、优质饮用水的净化工艺以及管网的设计。     

优质饮用水深度处理技术探讨

针对某市管网有机微污染水 ,采用纳滤把关处理方案 ,实现去除有毒有害物质 ,保留有益健康元素的目的 ,使出水水质符合优质饮用水的要求。     

饮用水水质处理技术在农村饮水安全工程中的应用研究

根据地下水铁锰超标的机理，结合辽宁省农村饮水不安全现状及农村饮水工程现状，探讨铁锰超标饮用水的水处理技术，比较传统的氧化法除铁锰技术与离子交换法除铁锰技术的优缺点，通过实际应用，研究适宜于农村饮用水的水质处理技术。