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）.

Spatial variation of health risk of groundwater for drinking water supply in Mingshan County,Ya'an City,China

Rural drinking water safety is a growing concern in China. This study investigated the health risk of pollution of groundwater for the drinking water supply in Mingshan County, Ya＇an City, in Sichuan Province, China, using 46 samples from the years 1991 to 2010. Carcinogenic, non-carcinogenic, and total risks were assessed by the model recommended by the United States Environmental Protection Agency （U.S. EPA）. Thematic maps of the risks caused by single and multiple factors were generated from inverse distance weighting interpolation （IDW） and the geostatistical analysis functions of ArcGIS. The results show that the carcinogenic risks caused by chemicals in groundwater for drinking water supply are low, within the acceptable interval for risk management. However, non-carcinogenic risks are high and the number of sampling sites with risk values exceeding the standards amounted to 29. Non-carcinogenic risks of Cr6＋, nitrate, fluoride, and Fe at sites 43, 46, 50, 64, 67, and 74 were the sources that caused high total health risk. This study reveals the risk level of groundwater quality and orders of treatment of pollutants, and provides a scientific basis for groundwater management in this area.

Emergency Plan for Water Supply in Consecutive Droughts and Sustainable Water Resources Management in Beijing

Beijing, the capital city of China, has suffered from acute water shortage, with only 300 m3/a of water resources available per capita. In addition, Beijing has experienced a prolonged period of consecutive droughts from 1999 to 2010. Water crisis has constrained the socio-economic development of Beijing. Meanwhile, the national "South-to-North Water Transfer"（STNWT） project, which is expected to provide some relief to the water crisis in Beijing, is still under development. In order to ensure the security of water supply in Beijing before the completion of the STNWT project, several measures have been implemented to cope with droughts, including pumping groundwater from emergency well fields,water saving, recycling of water, rain and flood water harvesting, and the diversion of water from neighboring rivers and groundwater basins. Groundwater from four emergency well fields contributes the most to the public and domestic water supplies in Beijing, supplying a total volume of 1.8×10;m;.The water crisis is supposed to be mitigated by the completion of the STNWT project. After the completion of this project, more sustainable management of water resources will be implemented,including the use of aquifers as groundwater reservoirs and conjunctive use of surface water and groundwater resources.

Analysis on the situation and countermeasures of water resources supply and demand in the cities of small and medium-sized river basins along southeast coast of China-taking Xiamen City as an example

The small and medium-sized river basins along southeast coast of China hold comparatively abundant water resources.However,the rapid resources urbanization in recent years has produced a series of water problems such as deterioration of river water quality,water shortage and exacerbated floods,which have constrained urban economic development.By applying the principle of triple supply-demand equilibrium,this paper focuses on the estimation of levels of water supply and demand in 2030 at different guarantee probabilities,with a case study of Xiamen city.The results show that water shortage and inefficient utilization are main problems in the city,as the future water supply looks daunting,and a water shortage may hit nearly 2×10^(8)m^(3)in an extraordinarily dry year.Based on current water supply-demand gap and its trend,this paper proposes countermeasures and suggestions for developing and utilizing groundwater resources and improving the utilization rate of water resources,which can supply as a reference for other southeast middle-to-small-sized basin cities in terms of sustainable water resources and water environment protection.

Reflections on the Construction of Water Supply and Drainage in Integrated Pipe Corridor of Sponge City

With the continuous development of economy and society and the continuous improvement of peoples’living environment requirements,the concept of sponge city construction has been recognized and understood by more and more people.The country has also recognized the significance of planning and construction of sponge cities.In the process of planning and constructing a sponge city,it is necessary to combine the reality of urban development with the construction of urban water supply and drainage systems and underground pipe corridors to promote the process of urban modernization.Based on this,this paper analyzes the water supply and drainage construction of the integrated pipe corridor in the sponge city.

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.

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.

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.

Functionality analysis of an urban water supply network after strong earthquakes

An urban water supply network(WSN)is a crucial lifeline system that helps to maintain the normal functioning of modern society.However,the hydraulic analysis of a significantly damaged WSN that suffers from pipe breaks or leaks remains challenging.In this paper,a probability-based framework is proposed to assess the functionality of WSNs in the aftermath of powerful earthquakes.The serviceability of the WSN is quantified by using a comprehensive index that considers nodal water flow and nodal pressure.This index includes a coefficient that reflects the relative importance of these two parameters.The demand reduction(DR)method,which reduces the water flow of nodes while preventing the negative pressure of nodes,is proposed.The difference between the negative pressure elimination(NPE)method and the DR method is discussed by using the example of a WSN in a medium-sized city in China.The functionality values of the WSN are 0.76 and 0.99 when nodal pressure and nodal demands are used respectively as the index of system serviceability at an intensity level that would pertain to an earthquake considered to occur at a maximum level.When the intensity of ground motion is as high as 0.4 g,the DR method requires fewer samples than the NPE method to obtain accurate results.The NPE method eliminates most of the pipes,which may be unrealistic.

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.

Water System Management in Emergency Situations

This article deals with the issue of water system management and emergency management of water supply systems based on experience with the operation of water systems in EU （European Union） Member States. The options available for prevention/elimination of the hazard of limited drinking water supply to the public are described. Current climate and, in some countries, also the existing social conditions pose barriers to a smooth water supply to the public. Various hazards endangering the quality and amounts of water produced emerge. Since the risk of water supply outages due to natural or anthropogenic factors cannot be completely eliminated （for instance, hacker attacks pose a new threat to the water companies＇ control systems）, in other words, emergency situations where smooth water supply is disturbed cannot be ruled out, efforts must be made to at least minimise adverse impacts of such events on the users. Organisational and technical conditions minimising such hazards must be set up. A water production and distribution organization and management system must be introduced, which will be able to prevent and address such hazards and emergency situations. How to tackle this complex task in the real water system management conditions and to assure some minimal amount of water at least for strategic consumers is discussed in this article. The results of a water system operation risk analysis are presented, feasible methods to minimize such risks are described, and options to prevent and address such risks are proposed. A water company organisation and management system taking into account the possibility of development of emergency situations is set forth. Focus is on the use of a telemetric system as a system means that facilitates the prevention and possible addressing of any emergencies occurring during the operation of a water supply system.

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.

Characteristics of groundwater and urban emergency water sources optimazation in Luoyang,China

The construction of emergency water sources is the material basis for ensuring urban water safety,and it is also an inherent requirement for maintaining social stability and development.The hydrogeological characteristics of groundwater in Luoyang City from the aspects of the division of groundwater aquifer groups,water yield property and groundwater dynamics were described in this paper.Two emergency water sources were selected on basis of comprehensively considering groundwater resources and ecological environmental effects,groundwater quality and exploitation technology,etc.Then it further analysed the aquifer types,water yield properties and groundwater recharge,runoff and discharge conditions of the two emergency water sources,and evaluate the groundwater resources quantity of the water sources.The results are that the shallow underground aquifer in Luoyang City is thick,coarse,and stable in lithology and thickness.The two water sources enjoy good exploitation potential and can be used as backup water sources to supply water in the event of a water source crisis.

Behaviour of Haloacetic Acids in Drinking Water Distribution Systems

To guarantee the safety of drinking water quality after chlorination, the formation, distribution and factors influencing the concentrations of haloacetic acids (HAAs) in a water distribution system (WDS) were investigated both on a full-scale WDS (FWDS) and pilot-scale WDS (PWDS) within a city in northern China. The results of both investigations showed that trichloroacetic acid (TCAA) and dichloroacetic acid (DCAA) were the dominating types of HAAs. In the FWDS, variations in the HAA content showed negative correlations with total residual chlorine, pH and non-purgeable organic carbon (NPOC) and positive correlations with temperature and UV254. In the PWDS, the concentration of HAAs after rechlorination followed the rule of ‘first rise and then fall’; therefore, locating an appropriate rechlorination point and lowering the single chlorine dosage could be used as effective measures to control the HAA content in WDSs. © 2016, Tianjin University and Springer-Verlag Berlin Heidelberg.

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.

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.

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.