Households＇ Assessment of the Water Quality and Services of Multi-model Urban Water Supply System in the Informal Settlements of Dar es Salaam, Tanzania

In the global south wide range of studies highlight the limitations of the single-modelled public urban water system to meeting the endogenous water preferences of the urban population. Studies also touched on the complementary roles of private water actors to the single-modelled public water supply system in the urban water supply network. Multiple of urban water supply systems （multi-model） co-exist in the urban landscape of global south. However, it is unclear and largely inconclusive on the suitable and satisfactory urban water supply model that meets the water consumption needs of informal settlement dwellers in the global south. This study draws the experiences of households in the informal settlements using a case-study with cross-sectional survey strategy to assess the suitability of the multi-model urban water supply system for sustainable urban water supply in the informal settlements. A total of 292 households were randomly sampled alongside 35 purposively sampled private water actors and public water departments. The data were collected through face to face interviews. Findings show that water supply services of the multi-model water supply system are inevitably suitable for the water consumption needs of informal settlements’s dwellers. The operation of the multi-model water supply system is flexible and able to accommodate the diverse water consumption preferences and choices of the different socio-economic groups in the informal settlements. We observed that multiplicity of urban water supply system increases households’ access to water but does not necessarily improve the quality of water serve in the informal settlements. The paper recommended for the formalisation and adoption of the multi-model urban water supply system to meet the growing demand for improved water supply and services in the informal settlements.

Geostatistical Studies of Space-Temporal Variation in Selected Quality Parameters in Klodzko Water Supply System （SW Part of Poland）

Selected results of research connected with the development of a （3D） geostatistical hydrogeocbemical model of the Klodzko city area, dedicated to the spatial and time variation in the quality parameters in the Klodzko water supply system （SW part of Poland） have been presented. The research covers the period 2007-2011. Spatial analyses of the variation in three quality parameters, i.e. Fe iron （g/m3） content, Mn manganese （g/m3） content and NI-I4＋ ammonium ion （g/m3） content, were carried out. Spatial and time variation in the parameters was analyzed on the basis of the data （2007-2011）. The input for the studies was the chemical determinations of the quality parameters of water samples taken in the Klodzko water supply system area （also treated water） in different periods of time. These data were subjected to spatial analyses using geostatistical methods. The parameters of the assumed theoretical models of directional semivariograms functions of the studied regionalized variables, were used in the ordinary （block） kriging estimation. Generally, the behaviour of the quality parameters in the Klodzko water supply system has been found to vary in space and time. Thanks to the multivariate spatial analyses some regularities in the variation in the water supply system in the Klodzko city area have been identified. In the considered time interval, the shapes of the directional Fe iron content semivariogram show a tendency to vary periodically. The courses of the directional semivariograms of Mn manganese content and NI-I4＋ ammonium ion content show some tendencies towards directional variation over the passing years. There are visible distinct increasing trends of variability for Mn content and stronger variation are observed for NH4＋ ion content. The kriging estimation results were used to determine the levels of elevated values 2＊ of the water quality parameters in the years 2007-2011 and to forecast these values for the years 2012-2014. The maximum values Z＊ of the quality parameters were stated for the years： 2007, 2008-2009 and 2012 （the decreasing trend in Fe iron content averages Z＊ variation towards the year 2012, the increasing trend in Mn content averages Z＊ variation towards the year 2012 and the increasing trend in NH4＋ ion content averages Z＊ variation towards the years 2008-2009 and then the decreasing trend towards the year 2012）.

A Stacked Ensemble Deep Learning Approach for Imbalanced Multi-Class Water Quality Index Prediction

A common difficulty in building prediction models with real-world environmental datasets is the skewed distribution of classes.There are significantly more samples for day-to-day classes,while rare events such as polluted classes are uncommon.Consequently,the limited availability of minority outcomes lowers the classifier’s overall reliability.This study assesses the capability of machine learning(ML)algorithms in tackling imbalanced water quality data based on the metrics of precision,recall,and F1 score.It intends to balance the misled accuracy towards the majority of data.Hence,10 ML algorithms of its performance are compared.The classifiers included are AdaBoost,SupportVector Machine,Linear Discriminant Analysis,k-Nearest Neighbors,Naive Bayes,Decision Trees,Random Forest,Extra Trees,Bagging,and the Multilayer Perceptron.This study also uses the Easy Ensemble Classifier,Balanced Bagging,andRUSBoost algorithm to evaluatemulti-class imbalanced learning methods.The comparison results revealed that a highaccuracy machine learning model is not always good in recall and sensitivity.This paper’s stacked ensemble deep learning(SE-DL)generalization model effectively classifies the water quality index(WQI)based on 23 input variables.The proposed algorithm achieved a remarkable average of 95.69%,94.96%,92.92%,and 93.88%for accuracy,precision,recall,and F1 score,respectively.In addition,the proposed model is compared against two state-of-the-art classifiers,the XGBoost(eXtreme Gradient Boosting)and Light Gradient Boosting Machine,where performance metrics of balanced accuracy and g-mean are included.The experimental setup concluded XGBoost with a higher balanced accuracy and G-mean.However,the SE-DL model has a better and more balanced performance in the F1 score.The SE-DL model aligns with the goal of this study to ensure the balance between accuracy and completeness for each water quality class.The proposed algorithm is also capable of higher efficiency at a lower computational time against using the standard SyntheticMinority Oversampling Technique(SMOTE)approach to imbalanced datasets.

Effect of continuous negative pressure water supply on the growth, development and physiological mechanism of Capsicum annuum L.

Effects of continuous negative pressure water supply on water consumption, growth and development, as well as physiological mechanism and quality of Capsicum annuum L. were investigated in this paper. Meanwhile, the optimal negative pressure water supply conditions for growth of C. annuum L. were screened out to achieve the goals of water conservation, high yield and high quality, thus providing theoretical foundation for its field production. The pot experiment within the greenhouse was utilized; the continuous negative pressure water supply was adopted; the four treatments, artificial watering（CK）, –5 k Pa（T1）, –10 k Pa（T2）, and –15 k Pa（T3） were set; and the daily water consumption, yield, as well as the biomass, nitrate reductase, root activity, vitamin C, capsaicin, and nutrient uptakes of nitrogen（N）, phosphorus（P） and potassium（K） during various stages of its growth were determined. Compared with CK, when the water supply pressure was controlled at –5 to –15 k Pa in the experiment, the total water consumption of C. annuum L. reduced by 53.42 to 67.75%, the total water consumption intensity reduced by 54.29 to 67.14%, and the water use efficiency increased by 12.66 to 124.67%. The N accumulation in a single strain of C. annuum L. from the color turning stage to the red ripe stage increased by 15.99 to 100.55%, respectively, compared with that of CK; the P accumulation increased by 20.47 to 154.00% relative to that of CK, and the K accumulation increased by 64.92 to 144.9% compared with that of CK. Compared with CK, C. annuum L. yield was remarkably improved by 13.79% at T1, and contents of vitamin C, capsaicin as well as carotenoids at all growth stages were enhanced by 13.42–147.01%, 11.54–71.01%, and 41.1–568.06%, respectively. Nitrate reductase activity, root activity and chlorophyll（a＋b） were markedly increased by 335.78–500%, 79.6–140.68% and 114.95–676.19%, respectively, from immature stage to full ripe stage. Adopting the continuous negative pressure water supply for C. annuum L. has a significant water-saving effect, and the water supply pressure being stable at –5 k Pa contributes to its growth and development, improves yield, enhances root activity, promotes nutrient uptake, and improves its quality, thus achieving the effects of water conservation, high yield, high quality and high efficiency.

A Study on the Microbial Quality of Drinking Water in Rural Areas of Mazandaran Province in North of Iran (2011)

Backgrounds: One of the fundamental needs of a community is to have an access to healthy and safe drinking water. The lack of a concentrated accessibility to health facilities and services is among the serious problems facing villagers in the rural areas. The aims of this research was to investigate the drinking water quality of the villages in Babol township suburbs in north of Iran. Materials and Methods: In this cross-sectional descriptive study, a total of 140 water samples were taken from the water distribution network in16 villages for the low and high-rain seasons in sterile glass bottle. The microbial quality of gathered samples were determined based on standard methods in laboratory. Statistical analysis of the results was performed using a SPSS16 statistical software. Findings: Based on obtained results 13.6% of the samples were contaminated to coliform and 20% to fecal coliform bacteria. The residual chlorine in 12.5% of the samples were between 0.2 to 0.8 mg·L-1 and the PH in total samples were between 6.8 to 7.8. There were no signs of any contamination for 32.86% of the analysed samples which water resources is located to a distance of more than 30 m to the contamination sources. In addition, 43.1% of the samples taken from the water resources with no plumbing system, have had a fecal contamination. Conclusions: Considering the results achieved, the microbial quality of the drinking water of the studied villages classified as “moderate” status. For more water supply there is not sufficient residual chlorine in most cases. Poor sanitation of water supply is most causes of water contamination. It is therefore strongly recommended that sanitation measures are made to protect water resources from the contamination.

Quality of Water Adjusted Sources and Storage in the Households of the Sanitized Villages in Area of National Program of Sanitized Schools and Villages at Tshopo Province in Republic Democratic of Congo

Introduction: The present research paper aims at assessing the bacteriological water quality in households and at provisioning points, and so factors of water deterioration. Method: a transverse study has been conducted during the period starting from 11 up to 28 October 2018 within 6 Health Zones (HZ) in Tshopo Province integrated in National Program of Schools and Sanitized Villages (NPSSV). Water samples have been collected within 300 reserves of households and 30 water provisioning and analysed points in order to find out water contamination factors. The frequencies and raw OR have been estimated at (p < 0.05) valued significative. Results: fecal coliforms (80% CI95: 75% - 85%) and total (97% CI95: 95% - 99%) were significantly present in water reserves and the presence of Escherichia coli were at about 27% (IC95 22% - 32%). These proportions were correspondingly at 63%, 90% and 10% at water provisioning. The fecal coliforms were the highest in water reserves of sanitized villages (p < 0.05) and Escherichia coli were at about three times higher in traditional sources (17% vs 6%). The duration of water conservation was around 48 hours and more (OR = 4.41;IC95: 1.92 - 10.11), water classification of sanitized risk “intermedium” and the recipients of conservation with bottleneck were associated with the presence of E.coli in water (p < 0.05). Conclusion: water from provisioning sources and household reserves are severely polluted and water quality is not good at consumption point and at provisioning point. The reinforcement of safety measures at water points, reduction of conservation length and hygienic water cleaning of storage water recipients are necessary to assure quality of water.

Application of Water Quality Index(WQI)and Regression Analysis of Groundwater in Budigumma Village,Anantapur District,Andhra Pradesh

The research work is aimed at assessing the subsurface or groundwater suitability for human use or consumption depends upon the calculated water quality index values,correlation coefficient and regression analysis.The water quality index(WQI)is main important tool to calculate the characteristics of drinking water quality in rural,urban and industrial area.Different parameters which is measured and determination of the water quality index for selecting parameters.Further to study the correlation and regression method in this research work.Totally fifteen groundwater samples were collected from the Budigumma Village Anantapur district in the state Andhra Pradesh in India.Nine water quality parameters has been considered for the computation of water quality index such as pH,total dissolved solid(TDS),total hardness(TH),calcium(Ca),magnesium(Mg),nitrates(NO3),chlorides(Cl),sulphates(SO4),fluorides(F).The World Health Organization(WHO)has been assessed to the suitability of groundwater for drinking purposes or other uses for public and determining of WQI.This WQI index values ranged from 97.78 to 108.37.The study shows that 87%area comes under the poor category of drinking purposes and the remaining 13%comes under as good water for drinking purposes as per the WQI classification.The correlation and regression analysis gives as an outstanding device for the calculation of different parameter values within realistic degree of precision.The subsistence of strong correlation or relationship between the total hardness and magnesium is determined.The analysis of selected parameters revealed that proper treatment before use or consumption and protected from more contamination.

Complex Sequence Quality Evaluation Model for Concealed Water Supply Pipeline of Prefabricated Construction

The accurate assessment of the quality can materially affect the safety and life of the prefabricated construction.In this paper,we studied the overall module of concealed water supply pipeline,and a new complex sequence quality evaluation model was established.By analyzing the small evaluation index elements of the model,the weight of the larger evaluation index could be deduced.The total quality evaluation score of the overall module could be obtained by calculating the weight value of the evaluation index,and then the quality standard of the overall module could be obtained.

Coupling Effect of Water and Phosphate on Economic Traits of Sugarcane

[Objective] The aim was to study the coupling effect of water and phosphate on economic traits of sugarcane. [Method] Taking sugarcane variety ROC22 as tested material,coupling effects of different levels of water supply quantity and different levels of phosphorus fertilizer on the yield and quality of sugarcane were studied. Among them,water supply quantity had 3 levels,that was,the water supply quantity per 10 days from the early tillering stage of sugarcane to the end of elongation was 199.5 m3/hm2 (A1),400.5 m3/hm2 (A2) and 600.0 m3/hm2 (A3),respectively; Phosphorus fertilizer as basic fertilizer had 4 levels:P2O5 0 kg/hm2 (B1),120 kg/hm2 (B2),240 kg/hm2 (B3) and 360 kg/hm2 (B4). [Result] Treatment A3B2 in water-fertilizer coupling was more suitable to improve economic traits of sugarcane. [Conclusion] The research results provide theoretical basis for the efficient utilization of water and phosphorus fertilizer in production of Guangxi sugarcane and the cultivation of high-yield and high-glucose sugarcane.

Drinking water quality & health risk assessment of secondary water supply systems in residential neighborhoods

Secondary water supply systems(SWSSs)are important components of the water supply infrastructure that ensure residents’drinking water safety.SWSSs are characterized by long detention time,warm temperature,and unreasonable management,which may trigger the deterioration of water quality and increase risks.In this study,drinking water quality index(DWQI)and health risk assessment(HRA)were selected and modified to quantitatively assess the water quality and health risks of SWSSs in residential neighborhoods.In total,121 seasonal water samples were selected.It was observed that the water quality was excellent with the DWQI of 0.14±0.04,excluding one sample,which was extremely poor owing to its excessive total bacterial count.The HRA results revealed that the health risks were low:negligible non-carcinogenic risk for any population;negligible and acceptable carcinogenic risk for children aged 6–17 and adults.However,samples revealed higher carcinogenic risk(7.63×10−5±3.29×10−6)for children aged 0–5,and arsenic was the major substance.Summer samples had poor water quality and higher health risks,which called for attention.To further investigate the water quality and health risks of SWSSs,monthly sampling was conducted during summer.All 24 water samples were qualified in Chinese standard(GB 5749-2022)and characterized as excellent quality.Their HRA results were consistent with the seasonal samples’and the health risks were mainly concentrated in May.Overall,our study provides a suitable framework for water quality security,advice for managers,and references for administrators in other cities.

Study on the Reservoir Water Quality Change Rule in Northern China

Water quality index of reservoir source water were tracked during three years in a north frigid area,the effect on supplied water quality was also studied.Based on the analysis of the monitoring data during the same season,the reservoir source water had typical and seasonal variation characteristics that was divided into four periods including the icebound period,spring period(or peach blossom period),stable period in summer and autumn and winter period.The icebound period was charactered by the typical low temperature and turbidity,pH and oxygen consumption decreased gradually showed that the gradually anaerobic trend existed in the reservoir.In May as the reservoir completely thawed,upstream water inflow and the total pollutant in the reservoir gradually increased,but the bottom of reservoir bottom was stable in the anaerobic state temporarily.The state completely disappeared,various index increased significantly in the middle of July.The water had high chroma characteristics,chroma and turbidity increased significantly in the summer and autumn(7-11months),but stability of water quality was poor because of rainfall.The reservoir gradually froze after the middle of November and the flow of water decreased.The peak of chroma appeared a month later than the water temperature.Due to the water turbidity was low,and the floc was small and light,the conventional water purification process design based on removal of turbidity achieved removal of chroma through a lot dosing of coagulant.

Consumer Preferences for Water Supply at Njala University, Njala Campus in Southern Sierra Leone

Suppliers of potable water would benefit from a sustainable business as long as consumers continue to prefer their brand. Some of the reasons for choosing a particular brand include water quality, cost of the finished product, reliability of supply, and supplier ethics. These important determinant factors form the basis of this work. The objective is to delineate consumer preferences for water supplied to the Njala campus community, in southern Sierra Leone, and the underlying determinant factors. A list of questions administered to 140 respondents, are used to help achieve the objective. The results of water quality tests are also used to determine if quality has anything to do with consumer preference. The Oxfam Delagua water testing kit is customized to incubate and enhance counting of fecal and no-fecal coliform bacteria in water samples. Bacterial contamination is the major concern in the study area. The survey results reveal the consumers prefer package water for drinking. Treated water from Tia River is only used for other domestic purposes. The consumers do not trust the quality of water supplied from Tia River, albeit filtration and disinfection at the University’s treatment center. This distrust is confirmed by the bacterial test. None of the campus water sources meet recommended guidelines for drinking water. The consumers are, however, willing to shift preference from package to tap drinking water if treatment comes with quality assurance. The university could benefit through economic gratification, customer protection, and reduced plastic waste from package drinking water.

Groundwater Quality Assessment for an Indian Urban Habitat： A GIS Approach

Groundwater is an essential source of drinking water for many Indian urban habitats. Large numbers of people consume ground water instead of municipal tap water due to contamination of tap water. Groundwater is extracted from thousands of bore wells, and used for potable purpose without proper testing and treatment. This paper describes a groundwater quality monitoring strategy and database model developed for Gulbarga city, located in Karnataka, India. Sampling wells are selected one each in 55 wards of the city corporation having easy access for regular sampling. Various attributes of sampling wells including their spatial coordinates, location address and a photograph are registered for ready recognition on site. Water samples are collected and analyzed for various physico-chemical parameters. Spatial coordinates and levels of sampling points are measured on site using a hand held GPS instrument. Gulbarga city map is digitized. A GIS database of the measured spatial and water quality data is developed using ArcGIS Desktop 9.3, and ground water quality maps are prepared which may serve as useful tools for developing policy, and regulatory mechanism for sustainable groundwater use.

Water Security Needs What Ought to Be Done to Increase the Future Water Security as a Fundamental Base for Social, Economic and Political Stability—The Case of Jordan

This study discusses the present water security situation in Jordan and delineates the required policies and programs to reach at a more robust and resilient water security situation. Although Jordan has achieved much in securing the different components of its water sector system, some components have still to be adequately addressed and others strengthened. Increasing the available water resources, which is practically only possible by desalinating sea water at Aqaba under sole Jordanian sovereignty, is found to be the most important and vital issue in improving the country’s water security situation. It improves the security issues of providing dearly needed additional water, releases the overexploited aquifers and saves them from depletion and quality deterioration, allows introducing new industries to Jordan, de-sharpens the conflict on the shared water resources with Jordan’s neighboring countries and is expected to render these conflicts to a problem of royalty on water resources and not as it is at present a social, economic, human, environmental and political conflict. Desalination will also make Jordan more resilient to climate change. Infrastructure security must be strengthened in Jordan both against natural hazards and against intended sabotage and damage. Water quality protection from pollution and deterioration has still to be adequately addressed requiring strengthening of laws and regulations and their application. The already delineated surface and groundwater protection zones have to be strictly adhered when licensing human activities in addition to implementing cybersecurity best practices. In addition, technology-dependent management tools have to be strongly advanced using integrated water resources management to ensure sustainable resource management, detection and repair of physical water losses and illegal water tapings, pricing water at its opportunity cost, irrigation modernization, strict environmental impacts assessment and application wherever water resources and water infrastructures are involved, and strengthening of training and management programs.

Conceptual Modelling and Data Based Techniques to Understand Urban Water Use and Wastewater Production

A systems approach is used to describe the generation and variation of wastewater in an urban area. This is a multivariable system and its combined response at the outlet of this system, which is usually the entrance ofa wastewater treatment plant, depends on a number of environmental （precipitation and temperature） as well as social （size of the urban area, population changes, water consumption per capita） variables. There is a large number of available models and tools for describing the urban water system, however, the interactions between the individual components are rarely considered within the same modelling framework. In this paper a parsimonious methodology is proposed in order to understand and estimate the wastewater generation and its characteristics in an urban area using any information provided by the available data. The model incorporates both the flows of stormwater discharge and wastewater production that arrive to the wastewater treatment plant. A state dependent variable is introduced to simulate the consumptive uses in the urban area. Data availability and system＇s complexity affect the ability to achieve enhanced model performance, however, in the presented case study, preliminary results from the application of the presented model in the Greater Athens Area illustrate the potential of the conceptual modelling approach.

水利高质量发展政策供给体系回顾与展望

近年来,水利部大力加强水利智库建设,围绕贯彻落实习近平总书记“节水优先、空间均衡、系统治理、两手发力”治水思路和治水重要论述精神、推动新阶段水利高质量发展,组织开展水利政策研究,加大水利政策供给力度,取得显著成效。展望今后一个时期,水利肩负新使命、面临新形势、承担新任务,亟需研究推动一批打基础、管长远、促发展的政策措施,以高质量水利政策研究助推水利高质量发展。

考虑水质因素的供水管网抗震韧性评估

城市基础设施系统抗震韧性分析模型是评估城市防震减灾能力并指导震后恢复工作的重要依据。提出了耦合水力与水质模拟的供水管网抗震韧性评估模型。根据管道地震易损性模型和Monte Carlo模拟生成管网地震破坏场景,并采用动态重要度方法模拟管网震后修复过程。通过管网中余氯浓度的降低表示地震破坏对管网水质的负面影响,震后管网余氯浓度的变化取决于管道破坏引起的供水路径和水量的变化。采用震后余氯浓度未下降的用户节点供水量,作为管网系统水质性能评估指标。所提出的模型应用于2个不同布局的Benchmark案例管网。研究结果表明:管道破损处的水量漏失导致其上游管道的水流量增加、余氯浓度增大,下游管道的供水路径延长、余氯浓度减小。管网的水质韧性值往往低于水力韧性值,水力和水质韧性相对差异程度受到管网布局和运行规则的影响,文中案例管网水质和水力指标计算的抗震韧性损失指标的相对差异在17%~286%之间;运行规则复杂且含有调节水箱的管网,其水力和水质韧性的差异较大。

一种基于多分类器和证据理论融合的水质分类方法

针对单分类器对不同水质类别识别不均衡、水质分类准确率较低、适应性较差的问题,提出一种基于多分类器和证据理论融合的水质分类方法。选取深度神经网络分类器、改进支持向量机分类器和贝叶斯分类器3种分类器,通过全概率公式构建信度函数,基于证据理论对信度函数进行融合,获得多分类器融合模型。从国家地表水水质自动站发布的2022年3月1—22日水质数据中选取3 558条数据为样本集,采用DNN水质分类模型、PSO-SVM水质分类模型、贝叶斯水质分类模型和多分类器融合模型对待测样本进行测试。结果表明:多分类器融合模型对水质类别判定的平均准确率、精确率、召回率和F1值分别为94.2%、93.8%、94.2%和94.0%。相较于DNN水质分类模型、PSO-SVM水质分类模型、贝叶斯水质分类模型,多分类器融合模型准确率分别提高5.6%、9.8%和13.6%,精确率分别提高5.2%、10.0%和10.9%,召回率分别提高5.6%、9.8%和13.6%,F1值分别提高5.4%、10.2%和12.3%,多分类器融合模型在水质分类方面的准确性和适应性更高。

广西农村水柜供水保障研究与实践

水柜供水作为广西大石山区农村供水工程体系的重要组成,目前在水量、水质、用户3个层面仍存在水资源匮乏、水质亟待提升、村民供水保障意识能力欠缺等问题。文章提出通过借助山泉水、河水、地下水和塘坝蓄水等手段,保障水源充足;通过强化水源保护、配套水处理设施和加强水质监测等方法,保证水质合格;通过加强宣传和培训工作,提升村民供水保障意识能力等解决对策。其中,强化水源保护主要从为水柜设置盖板、增加初雨弃流装置以及降低水源污染风险等途径出发,配套的水处理设施则需要根据水柜供水规模来选取,家庭水柜可选取以慢滤技术为主的水处理设施,集体水柜可选取以快滤技术为主的水处理设施。课题研究团队在上述调查研究的基础上,开展水源保障项目、水质提升项目、跟踪服务活动等探索实践,为水柜供水保障工作的实施提供了借鉴,助力广西农村供水高质量发展。

新时期节水产业高质量发展认识与思考

为推动新时期节水产业高质量发展,探讨了节水产业的定义和内涵,针对节水产业发展现状与问题,提出明确产业主体、坚持“两手发力”、做好供需匹配的节水产业高质量发展思路和“问诊供需关系、服务供需对接、畅通供需循环”的“三步走”新时期节水产业高质量发展路径,以期为节水产业的高质量发展提供参考和依据。