Urban Drinking Water Supply Research Articles

Adaptive urban drinking water supply model using the effect of node elevation and head loss formula: A case study

Along with population growth and health improvement, water demand due to urbanization is increasing and creating a need to develop a strategy for handling water supply networks (WSNs). In the last decade, software modeling of WSNs has been developed to evaluate the state of networks in terms of pressure control, leakage analysis, and overall demand determination. In the case of very complex and extremely large networks, it is very difficult to manage the water supply. Metropolitan Waterworks Authority (MWA) in Thailand has to supply drinking water to the three densely populated cities; Bangkok, Nonthaburi, and Samut Prakan, that cover an area of 2944.05 km2. Hence, MWA has developed a main pipe model using EPANET software as a managing tool. This tool can offer a good solution for the water supply, but there is approximately a 14 percent error, mainly due to not having the elevation data of the pipe network. The current research is based on demand and pressure modeling analysis with utilizing two important parameters, node elevations, and head loss. The first trial model was an initial revision of the node elevation based on a road surface map. It was found that the model with elevation data could offer a better solution and was 3.95% more accurate than the existing model. The result was significantly improved, but another error, which may have been caused by using an inappropriate head loss model, was found. As the introduced model is based on the Hazen-William model, it cannot offer an accurate solution for all Reynolds number ranges. Even though Darcy-Weisbach is more complex to use, it could provide a better solution. The results indicate the Darcy-Weisbach model produces results that are 8.65% more accurate than the Hazen-William model.

Investigating the Residue of Diazinon, Chlorpyrifos, and Dichlorvos in Urban Drinking Water Supply Sources and Determining the Water Quality Index in Tirano-Korun in 2020

Introduction: Contamination of water sources with toxins is an environmental problem and a serious threat to the health of societies. This study aimed to ascertain the remaining levels of toxins in urban drinking water networks and compute the water quality index.
 Materials and Methods: To examine the residual concentration of diazinon, chlorpyrifos, and dichlorvos in urban drinking water distribution networks, 35 underground and surface water sources were sampled in Tiran-o-Korun in Isfahan province, Iran. GC-ECD device was used to analyze the samples.
 Results: Diazinon was not observed in any of the sampling seasons. The maximum concentration of chlorpyrifos and dichlorvos was 61 and 100 ppb, respectively. Although chlorpyrifos was seen more in the hot season and dichlorvos in the cold season, the mean concentration of these toxins in different seasons was lower than the guidelines of Iran and the World Health Organization (WHO). The mean concentration of nitrate, and hardness, in wet and dry seasons was 46.23 and 46.42, and 343.7 and 338.8 mg/l, respectively.
 Conclusion: The mean and standard deviation of quality index of Iran's water resources (IRWQI) in wet and dry seasons were 52.16 ± 45.3 and 50.69 ± 15.8, respectively. The residual concentration of toxins in some water sources of this city exceeded the guidelines of Iran and the WHO in summer and spring.

Optimizing the Construction of the NUWSP SPAM Piping Network in Gresik Regency

Water is essential for all living things, including humans. Water, both in terms of quality and quantity, will have an effect on human life. The Indonesian government is preparing the National Urban Drinking Water Supply Plan (NUWSP) with assistance from the World Bank. A significant portion of the Bank's financial resources are allocated to technical assistance and capacity building in support of the Indonesian government's infrastructure expenditures in all urban water distribution platforms. The NUWSP Work was implemented during an 11-month period, from November 18, 2021 to August 22, 2022, with the NUWSP Work Location at Gresik Regency in East Java. During the data collection stages, both primary and secondary data were obtained. The drinking water supply system (SPAM) planning stage comprises calculating BOQ and RAB, as well as DED for drinking water, and planning for the drinking water JDU system. The contractor takes measurements and standards before installing a field-specific bow plank at the tying point. To avoid pipe damage, individual pipe fittings must be lowered into the trench using the right equipment. The volume of excavation is computed using a depth of 180 cm, a breadth of 60 cm, and a length of excavation of 31 km from six pieces of a pipeline. The Bill of Quantity (BOQ) and Budget Plan (RAB) necessary to complete the SPAM pipeline network work in Gresik Regency were IDR 27,823,590,000.00, based on the results and discussion of the Optimization of SPAM Network Work (NUWSP) in Gresik Regency.

Construction of pollution risk early warning model for urban drinking water supply chain

Abstract In order to improve the efficiency of urban drinking water safety monitoring and early warning management, a pollution risk early warning model of urban drinking water supply chain is proposed. Firstly, the current situation of urban drinking water supply is analyzed and the causes of pollution are analyzed. Then, the autoregressive model is used to predict the time series of multiple water quality indicators by constantly introducing new monitoring data modes for the residual vector group, the outlier scores of each vector group are obtained by using the isolated forest algorithm to judge whether the water quality is abnormal or not, and the fuzzy comprehensive evaluation method is used to evaluate the level of the abnormal situation and carry out the corresponding level early warning. The experimental results show that the area under the receiver operating characteristic curve can reach 0.919 when using the prediction residual vector group of turbidity and conductivity to detect the numerical changes of water quality parameters in the drinking water supply chain, accurately predict the abnormal data, make early warning, and provide the guarantee for the survival of urban residents and urban development.

Evaluating groundwater ponds for urban drinking water supply under uncertainty

Abstract Emerging deficits of drinking water in urban distributive systems require the application of sophisticated methodologies for assessing sources of water and deriving required strategic decisions about future development and exploitation of these sources. If there are more urban groundwater ponds of fresh water, their prioritization may help in planning allocation of human, technical, organizational, and other resources. Multi-criteria analysis and optimization, as a part of the decision-making process, can help in achieving the tasks. The possible approach is to use the fuzzy version of the analytic hierarchy process (AHP) and tackle this uncertain and imprecise process. Fuzzified AHP can be combined with fine-tuning mechanisms which emulate the optimism-pessimism behavior of decision-maker(s) and simulate their attitudes towards risk. The fuzzy decision-making (FDM) approach is presented for the evaluation of three groundwater ponds for freshwater supply in the city of Novi Sad, Serbia. The complete problem hierarchy is treated and a parallel control mechanism, the standard (crisp) version of AHP, is employed to assure a more convenient and reliable environment during the judgments performed by the decision-maker. Results encourage further research in the subject area.The applicability of the approach is considered relevant to other uncertainty-related problems.

Inter-Organizational Bench-Learning to Respond to Climate Change and Reduce Trade-Offs in Urban Drinking Water Supply: The Case of Grade 2B Municipalities in Oromia National Regional State, Ethiopia

Most studies on drinking water supply seem to focus on efficiency analysis and have failed to analyze effectiveness, cost-effectiveness, and trade-offs in performance management. Using Data Envelopment Analysis (DEA) and Free Disposal Hull (FDH) novel reference technologies, we analyzed the efficiency, effectiveness, and cost-effectiveness, and the social, economic and ecological performance (TBL elements) of 29 municipalities in drinking water supply, in Oromia National Regional State. The results from 42 (efficiency), 173 (effectiveness), and 37 (cost-effectiveness) DEA and FDH models on production model criterion and TBL elements reveal that performance of many municipalities was weak, and the municipalities encountered trade-offs on the production model criterion and TBL elements. We argue that inter-organizational bench-learning can improve performance, reduce trade-offs, and respond to the effect of climate change on the drinking water supply. To this end, we argue for the need to map peers for inter-organizational bench-learning. We identified five inter-organizational bench-learning strategies and drew implications. The article contributes to performance management literature and the debate on sustainable development.

Valuing urban drinking water supply attributes: A case study from Chile

This article uses a discrete choice experiment carried out in the city of Antofagasta, Chile, to understand consumer's preferences for urban drinking water. To disentangle the perceptions and valuation of drinking water attributes, we propose a willingness-to-pay (WTP)-space model where the WTPs for water attributes are distributed as a mixture-of-normal distribution. This approach combines discrete and continuous heterogeneity representations of tastes providing a richer interpretation of preference heterogeneity for drinking-water characteristics such as price, the organoleptic characteristics, information about the chemical composition, origin, and the taste of water by distinguishing between tap or bottled water. This mixture-based formulation is also flexible enough to identify clusters of individuals with differing WTP for these attributes. The elicited perceptions and inferred preferences derived from our results are important to understand why consumers still distrust tap water for drinking, though tap water meets Chilean regulations in terms of safety and is distributed within a stable network.

Spatiotemporal variation of bacterial communities in three cascade reservoirs in a southern city of China

Abstract Reservoirs are important water sources of urban drinking water supply. Bacteria play an important role in the removal of organics in reservoirs, but some of them can pose a health risk to consumers. Knowledge of bacterial community composition in drinking water sources can favour the drinking water security safeguards. This study investigated the monthly composition and diversity of bacterial communities in three cascade reservoirs using high-throughput Illumina HiSeq sequencing over one hydrological year. The diversity and structure of the bacterial community showed distinct spatiotemporal variation. Mycobacterium, Acinetobacter, Sphingomonas, Sphingobacterium and Pseudomonas were the genera resistant to chlorine. In addition, Acinetobacter, Arcobacter, Mycobacterium, Pseudomonas and Staphylococcus were the main potential pathogenic genera. The bacterial community diversity and the average relative abundance of potential pathogenic genera detected in the wet season were higher than those in the dry season. Water temperature was found to be the main factor for the temporal variation. The spatial variation of bacterial community diversity and the average relative abundance of potential pathogenic genera were related to water current and the degree of water pollution, respectively. The results of this study can conduce the beneficial management of drinking water treatment processes.

Urban drinking water security in Gujarat

Gujarat has made important strides to ensure that most parts of the state become water secure. In 2005, Gujarat was one of the few states that recognized that its urban areas were its ‘engines of growth’ and made significant investments in urban infrastructure. A state-wide water supply grid was constructed to transfer inter-basin water from perennial surface water sources to water-scarce areas. While these schemes have improved household-level access to municipal water supply, service levels have not improved. In this paper, we argue that along with infrastructure creation, there is a need to focus on monitoring, operation and maintenance of existing system and improving efficiency. We analyze information available from the performance assessment system (PAS) setup by the CEPT University for monitoring of urban services in India. It has annual information of water service delivery in all the urban areas of Gujarat from 2010. We assess urban drinking water supply on three key aspects: equity, service quality and financial sustainability. We also identify a few key intervention areas related to increased accountability, efficiency and equity in delivery of water supply services.

A new approach to the allocation of the blue water footprint of reservoirs using fuzzy AHP model

In some areas of the world, water reservoirs are the main water resources available for different purposes, including hydroelectricity, irrigation, residential and industrial water supply, recreation, flood protection, etc. However, a large amount of water is wasted through evaporation from the reservoirs’ surface area. In this study, a novel approach was developed based on the Fuzzy Analytic Hierarchy Process to allocate the blue water footprint of reservoirs (WFres) for different purposes including hydroelectricity, irrigation, water supply, recreation and flood protection. The effectiveness of the proposed approach was verified in Zayanderud multi-objective reservoir in Iran as a case study. The results showed that the environmental and social as well as the economic criteria with the local weight of 0.4 had the largest share of WFres. In addition, it was found that the highest allocation coefficient of WFres was for irrigation with the global weight of 0.412, followed by urban drinking water supply, recreation, hydroelectricity, and flood protection. Besides, the blue water footprint assessment of hydroelectricity generation showed that the previous studies had often overestimated the impact of hydroelectricity generation on water scarcity.

Tracking the contribution of multiple raw and treated wastewater discharges at an urban drinking water supply using near real-time monitoring of β-d-glucuronidase activity

Past waterborne outbreaks have demonstrated that informed vulnerability assessment of drinking water supplies is paramount for the provision of safe drinking water. Although current monitoring frameworks are not designed to account for short-term peak concentrations of fecal microorganisms in source waters, the recent development of online microbial monitoring technologies is expected to fill this knowledge gap. In this study, online near real-time monitoring of β-d-glucuronidase (GLUC) activity was conducted for 1.5 years at an urban drinking water intake impacted by multiple point sources of fecal pollution. Parallel routine and event-based monitoring of E. coli and online measurement of physico-chemistry were performed at the intake and their dynamics compared over time. GLUC activity fluctuations ranged from seasonal to hourly time scales. All peak contamination episodes occurred between late fall and early spring following intense rainfall and/or snowmelt. In the absence of rainfall, recurrent daily fluctuations in GLUC activity and culturable E. coli were observed at the intake, a pattern otherwise ignored by regulatory monitoring. Cross-correlation analysis of time series retrieved from the drinking water intake and an upstream Water Resource Recovery Facility (WRRF) demonstrated a hydraulic connection between the two sites. Sewage by-passes from the same WRRF were the main drivers of intermittent GLUC activity and E. coli peaks at the drinking water intake following intense precipitation and/or snowmelt. Near real-time monitoring of fecal pollution through GLUC activity enabled a thorough characterization of the frequency, duration and amplitude of peak contamination periods at the urban drinking water intake while providing crucial information for the identification of the dominant upstream fecal pollution sources. To the best of our knowledge, this is the first characterization of a hydraulic connection between a WRRF and a downstream drinking water intake across hourly to seasonal timescales using high frequency microbial monitoring data. Ultimately, this should help improve source water protection through catchment mitigation actions, especially in a context of de facto wastewater reuse.

An empirical study for sustainable policy intervention in urban drinking water supply management using performance indicators

An empirical study for sustainable policy intervention in urban drinking water supply management using performance indicators

An empirical study for sustainable policy intervention in urban drinking water supply management using performance indicators

This paper examines integration of performance indicators (PIs) and public-private partnership (PPP) in urban drinking water supply management for sustainable business. Our study takes evidence from a large Indian city, capturing the data for five years. The zones are treated as cost/profit centres for optimising the present value of PI. The specific PI shows significant performance difference due to operator, primarily examined by discriminant analysis and further proven statistically by independent sample t-test. The study considers four performance indicators which take care of consumer risk and financial risk of the operations. The results are compared with other cities to outline the broader trends. The study affirms that the optimisation of present value of PI may be used to present it for new business vistas. It also helps to convince all stakeholders about operational efficiency of water supply infrastructure which may become an objective basis for new policy intervention.

Identification of urban drinking water supply patterns across 627 cities in China based on supervised and unsupervised statistical learning

Urbanization, one of the predominant trends of the 21st century, places great stress on urban water supply networks. This paper aimed to identify the most important variables driving urban water supply patterns in China, a region which has seen rapid urban growth in the last few decades. In addition, a principal component analysis-informed urban water sustainability index was developed in order to benchmark cities. The research involved applying statistical learning and other analytical methods to 12 years of urban water supply data for 627 cities across China. The findings were as follows: (1) PCA showed that approximately 46.8% of variability in the data could be explained by two principal components. Component 1 (37.26%) was more closely associated with variables related to water supply and sale, supply pipelines, and water supply finance. C2 (9.51%) was clearly related to urban water prices and average per capita water use. (2) Random forest and XGBoost algorithms were effective in classifying cities according to their region, with model testing accuracies of 87.69% and 88.32% respectively. (3) Chinese cities have consistently suffered water loss/leakage rates above 20% since 2001, and water prices are closely associated with leakage. (4) China's urban water sustainability has increased by just 3.56% between 2001 and 2013; Southwest China saw the highest growth rate in urban water supply sustainability. The implications of our research effort will be useful for decision makers in water-stressed urban areas around the world who are seeking novel insights in how to leverage statistical learning techniques to gain insights into urban drinking water supply patterns.

Towards an Analytical Framework to Benchmark the Performance of Urban Drinking Water Supply

This paper aims at identifying strategies to improve the performance of Ethiopian local governments in supplying drinking water. Therefore, a case study of Ambo (Ethiopia) is performed, on basis of document analysis, interview and focus group discussion. This allows operationalizing Pollitt and Bouckaert’s (2011) production process model, by defining input, activity, output and outcome indicators relevant for drinking water supply in the context of developing countries. The indicators and their interrelations subsequently allow coining efficiency-improvement and effectiveness-improvement strategies. The paper finds that most performance improvement strategies do not involve a trade-off between efficiency and effectiveness: investing in the maintenance of the water distribution network, involving the community in the production process, ensuring a minimum quality threshold, improving procurement policies, and relying on ground water contribute to both and deserve being implemented. On other aspects, related to commercial policies and the quality of water, local policymakers need to make a choice between pursing efficiency and effectiveness. The paper contributes to the ongoing discussion on the added-value of governance for the 2030 Agenda, and paves the way for benchmarking Ethiopian local governments, and warrants further research onto the added value of participation for development.

Challenges of climate change impacts on urban water quality management and planning in coastal towns of Bangladesh

The Bangladesh coastal zone is the lowest lying zone in the world where 36 million people are living within 1 metre elevation from high tide level. The coastal ecosystem is supporting more than 15% of the total population of the country, is under varying degrees of environmental threats due to anthropogenic and climate change impacts. The clean coastal urban drinking water supply is now a crucial problem in the coastal Bangladesh; where almost 11 million people live in the coastal urban areas. The shortage of upstream fresh water supply, the global warming and climate impacts are the new threats for urban water supply management and planning of 136 towns. Almost 34 towns are severely affected by saline water intrusion. Therefore, climate awareness and applied research should be initiated to change the attitude of the people. The objective of this paper is to understand the impacts of climate change on urban water supply as well as management and planning of small towns in the coastal region of Bangladesh.

Extreme variability of cyanobacterial blooms in an urban drinking water supply

Harmful cyanobacterial blooms are of increasing global concern and their prediction and management requires an improved understanding of the controlling factors for cyanobacterial growth and dominance. In Lake St Charles, the drinking water supply for Quebec City, Canada, harmful cyanobacterial blooms were first recorded in autumn 2006. Our aims were to define the temporal and spatial variations in the cyanobacterial community structure of this reservoir and to address the hypothesis that interannual variability in cyanobacterial biomass and species composition is mainly controlled by nutrients, temperature and water column stratification. Over five consecutive summers (2007–2011), the north basin had consistently higher concentrations of bloom-forming cyanobacteria than the south basin, and there were striking variations within and among years in total biomass and species composition. Correlation analysis underscored the contrasting environmental controls on different taxa of colonial cyanobacteria. Anabaena flos-aquae biovolume was correlated with surface temperature, water column stability (Schmidt index) and water residence time whereas Microcystis aeruginosa was highly correlated with total phosphorus and to a lesser extent with total nitrogen (TN), heat accumulation (degree-days above 20°C) and precipitation. Aphanocapsa/Aphanothece correlated significantly only with TN. These results also imply the sensitivity of high through-flow reservoir ecosystems to interannual variations in environmental forcing.

How much are households willing to contribute to the cost recovery of drinking water supply? Results from a household survey

Abstract. Financial resources are crucial to improve existing urban drinking water supply in developing countries typically characterized by low cost recovery rates and high and rapidly growing demand for more reliable services. This study examines the willingness to pay for improved urban drinking water supply employing a choice model (CM) in an urban context in Ethiopia, Hawassa, with a household survey of 170 respondents. The design of the choice model allows the estimation of the values of two attributes of urban drinking water service (extra day water delivery per week and safer water). The findings indicate that households are willing to pay up to 60% extra for improved levels of water supply over and above their current water bill. Especially those households living in the poorest part of the city with the lowest service levels demonstrate that they are willing to pay more despite significant income constraints they are facing. Women value the improvement of water quality most, while a significant effect is found for averting behavior and expenditures. The estimated economic values can be used in policy appraisals of investment decisions.

Serotyping, PCR, phage-typing and antibiotic sensitivity testing of Salmonella serovars isolated from urban drinking water supply systems of Nepal

To study the occurrence and diversity of Salmonella serovars in urban water supply systems of Nepal. Occurrence of Salmonella was detected in 42 out of 300 water samples by enrichment culture technique in selenite F broth followed by plating on Salmonella Shigella agar. A total of 54 isolates identified to genus level by standard tests were subsequently confirmed by serotyping, phage typing and PCR detection of virulence genes (inv A and spv C). The predominant serotype was Salmonella Typhimurium, followed by Salm. Typhi, Salm. Paratyphi A and Salmonella Enteritidis. Most of the Salm. Typhi isolates were E1 phage type followed by UVS4, A and UVS1. All isolates of Salm. Paratyphi A and Salm. Enteritidis were an untypable (UT) phage type. The majority of isolates were multi-drug resistant as revealed by Kirby-Bauer disc diffusion technique. Ceftriaxone resistant isolates of Salm. Enteritidis indicated the presence of one of the ESBL genes, blaSHV, whereas the genes blaTEM and blaCTX were absent. The microbiological quality of the urban water supply is poor and indicates possibility of fatal outbreaks of enteric fever and related infections in Nepal. The present study will be useful in water borne disease control and prevention strategy formulation in Nepal and in the global context.

Induced alkoxyresorufin- O-dealkylases in tilapias ( Oreochromis niloticus) from Guandu river, Rio de Janeiro, Brazil

The activity of fish monooxygenases has been extensively used as a monitoring tool to detect contamination of water bodies by cytochrome P450-inducing agents. In this study we evaluated the activities of ethoxy- (EROD), methoxy- (MROD) and pentoxy- (PROD) resorufin- O-dealkylases in the liver of Nile tilapias ( Oreochromis niloticus) collected at the Guandu river, at a reference clean site (Lake 1) and at two other sampling sites (Lakes 2 and 3) in Rio de Janeiro state, Brazil. Alkoxyresorufin- O-dealkylases were measured fluorimetrically in the hepatic S9 fraction. EROD (17.7-fold), MROD (14.2-fold) as well as PROD activities were considerably higher in tilapias from Guandu river. A moderate increase of EROD (5.0-fold) and MROD (5.4-fold) was also found in tilapias from Lake 3. These findings suggest that Guandu river watershed, the main source of urban drinking water supply in Rio de Janeiro, is polluted with CYP1A-inducing xenobiotics. Furthermore, we also found a good linear relationship between EROD and MROD, a finding that agrees with the hypothesis that the two reactions are catalysed by the same CYP1A isoform in O. niloticus.