Performance Of Water Distribution Networks Research Articles

Integrated Sustainability Index for Assessing the Performance of Water Distribution Network

Integrated Sustainability Index for Assessing the Performance of Water Distribution Network

Hydraulic and Utility Performance Evaluation of Ataye Town Water Distribution Network, Ethiopia: case for small towns in developing countries

Evaluating hydraulic and utility performance of water distribution network is a way to check the functionality degree of a system. Water CAD software was used in developing a model and evaluating the hydraulic performance of water distribution system of Ataye Town, Amhara Region, Ethiopia. Both steady state and extended period simulation analysis were carried out to determine hydraulic parameters (pressure and velocity). The model was calibrated using Darwin Calibrator and validity was checked by both correlation coefficient and scatter plot. The utility performance was also evaluated using international water association performance indicators. The simulated result for steady state analysis showed that 68.7% of the nodes operated within optimum adopted pressure (15-60 meter) and 93% of the distribution pipes had a velocity of <0.6 m/s which was a minimum adopted velocity. For extended period simulation 34.3% during maximum demand time and 16.8% during minimum consumption hours had pressure <15meters. 10.8% had negative pressure during maximum demand hours located at Sudan, Selama, and Zigba sefer and 14 nodes (8.4%) during low consumption time had a pressure greater than 60meter, which was a maximum adopted pressure. The areas of high pressure were located at around mosque, Worku Hotel and Hamus Gebaya. The distribution system performs within the adopted pressure at minimum demand time (74.7%) and maximum consumption hours (65.1%). 23.5% of the systems had a velocity of 0.6-2 m/s and the rest had a velocity less than 0.6m/s during high demand time. During low consumption hours, 100% of the system velocity was estimated to be <0.6m/s. Based on the IWA performance indicators, water utility of Ataye Town was evaluated and had low, technical, financial, personnel, and environmental performances. Finally, the distribution system was modified and optimized by providing alternative connections with pressure reducing valves and changing pipe diameter to improve the hydraulic performance and reduce system disruption of the Town.
 Keywords: Extended period simulation; Hydraulic performance; IWA Utility performance; Steady state analysis; Water CAD

Adaptive MPC for Burst Incident Management in Water Distribution Networks

This paper investigates an adaptive control strategy which takes advantage of remotely actuated pumps and valves to improve the performance of water distribution networks (WDN) during burst incidents. The proposed strategy relies on model predictive control (MPC) to switch between problem formulations corresponding to normal operating conditions and burst conditions. The optimal control problems are formulated as non-convex non-linear programs (NLP), where the action of fixed-speed pumps and control valves (non-return and bi-directional) is modeled exactly and burst remedial interventions are represented using time-dependent connectivity matrices. We propose an efficient solution method based on reformulations and approximations of the non-convex objectives and constraints and apply the proposed strategy to the adaptive control of an operational WDN during a burst incident. The numerical experiments show that the computed burst control settings allow to partially or completely restore customer supply following the detection of a burst while maintaining minimum water levels in the network tanks and without increasing the cost of pumping operations. The results suggest that the proposed adaptive control strategy can be implemented alone, to mitigate the impact of bursts incidents in WDNs at minimum cost, or to complement traditional remedial interventions.

Evaluation of current and future water demand scenario and hydraulic performance of water distribution systems, a case study for Addis Kidam Town, Ethiopia

The hydraulic performance and future water demand of water distribution networks are major factors affecting the efficiency of water distribution systems throughout the world. Currently, Addis Kidam Town in Ethiopia is facing many water supply challenges. Their existing water distribution system is inadequate experiencing significant water loss, pressure, and flow velocity. All becoming worse with forecast population increases. The main objective of this study was to evaluate the hydraulic performance of the water distribution network considering both the existing water demand, together with forecast future water demand. The study was undertaken in Addis Kidam Town in Ethiopia using static analysis and WaterGEMS V8i software. The data were collected using experiment tests, field observation, focus group discussions, and interviews. Sampling sizes of pipes and junctions of distribution networks were used to evaluate velocity and pressure changes of 12% and 15%, respectively, from high and low-pressure zones. The results of this study indicated that the existing distribution network was designed to supply a population of 8,906; however, the current population was 25,854. The existing system can accordingly not meet current demand. The current system was only supplying 19.5 l/c/d to each family and was only able to supply 45.2% of households. All compounded because water loss of the distribution network was 37.9%. Simulation of existing distribution network at junctions and pipes has both 26.6% and 4.3%, and 2.4% and 29.9% lower pressures and velocities during peak and minimum hourly demand, respectively. Model performance values of RMSE, MAE, R2, and NSE of distribution networks were 0.65, 0.40, 0.96, and 0.82 and 0.56, 0.38, 0.98, and 0.78 during the calibration and validation of pressure, flow, and tank level, respectively. The research recommends a two-phase strategic water distribution system response beginning by upgrading and expanding the water distribution network, to first achieve a supply of 30 l/c/d by 2032, and then lifting this to the 30–80 l/c/d range before 2042. The proposed water management upgrading approach is expected to establish a good water supply for all residential communities of the town facing comparable challenges. In general, this study’s findings showed that the existing water supply system could not meet the present demand, let alone meet future growth demand. The existing modeling highlighted that significant increases in supply are possible by targeting system improvements, together with the need to find additional supply to meet both present and future water demand.

Optimal Operational Scheduling of Pumps to Improve the Performance of Water Distribution Networks

Optimal Operational Scheduling of Pumps to Improve the Performance of Water Distribution Networks

Probabilistic zoning of hydraulic performance of water distribution network by applying key parameter uncertainty

در این مقاله، ابتدا مقادیر قطعی پارامترها در سال‌های مختلف در طول دوره طرح برآورد شده و سپس با استفاده از توزیع نرمال برای ضرایب هیزن‌ویلیامز لوله‌ها و مصارف گره‌ها و توزیع ریسک برای قطر لوله‌ها، مقادیر غیرقطعی آنها محاسبه گردیده است. با اعمال مقادیر غیرقطعی به مدل شبیه‌ساز شبکه سطوح کارایی شبکه به صورت احتمالاتی تعیین شده است. مدل‌سازی در محیط MATLAB و با لینک با شبیه‌ساز شبکه (EPANET) انجام شده است. مدل‌سازی عدم‌قطعیت پارامترها با روش مونت‌کارلو در دو حالت ضریب تغییرات 10 و 20 درصد و کارایی هیدرولیکی شبکه با ارزیابی شاخص قابلیت اطمینان فشار گرهی شبکه (NPRI) انجام شده است. روش پیشنهادی بر روی شبکه توزیع آب کلیبر پیاده‌سازی شده است. نتایج نشان می‌دهد که در هر دو حالت، بالاترین سطوح عملکرد شبکه با احتمال وقوع زیاد در سال‌های اولیه دوره طرح در ساعت‌های حداکثر مصرف و در سال‌های انتهای دوره طرح در ساعت‌های متوسط مصرف اتفاق می‌افتد. همچنین بررسی روند تغییرات سالانه سطوح عملکرد شبکه نشان می‌دهد که در حالت ضریب تغییرات 10 درصد، بهترین سرویس‌دهی شبکه در سال 23 با احتمال 55 درصد عملکرد قابل‌قبول و در حالت ضریب تغییرات 20 درصد، بهترین سرویس‌دهی شبکه در سال20 با احتمال 46 درصد عملکرد قابل قبول اتفاق می‌افتد. در مجموع پهنه‌بندی احتمالاتی کارایی هیدرولیکی شبکه بازخورد دقیقی از سرویس‌دهی شبکه بدست می‌آورد که می‌تواند در تصمیم‌گیری در جهت اعمال برنامه‌ریزی مدیریت بهره‌برداری یا بازسازی و نوسازی شبکه موثر باشد.

Sensitivity Analysis for Performance Evaluation of a Real Water Distribution System by a Pressure Driven Analysis Approach and Artificial Intelligence Method

Proper performance of water distribution networks (WDNs) plays a vital role in customer satisfaction. The aim of this study is to conduct a sensitivity analysis to evaluate the behavior of WDNs analyzed by a pressure-driven analysis (PDA) approach and the classification technique by using an appropriate artificial neural network, namely the Group Method of Data Handling (GMDH). For this purpose, this study is divided into four distinct steps. In the first and second steps, a real network has been analyzed by using a Pressure-Driven Analysis approach (PDA) to obtain the pressure, and α coefficient, the percentage of supplied flow. The analysis has been performed by using three different values of the design peak coefficient k*. In the third step, the Group Method of Data Handling (GMDH) has been applied and several binary models have been constructed. The analysis has been carried out by using input data, including the real topology of the network and the base demand necessary to satisfy requests of users in average conditions and by assuming that the demand in each single one-hour time step depends on a peak coefficient. Finally, the results obtained from the PDA hydraulic analysis and those obtained by using them in the GMDH algorithm have been compared and sensitivity analysis has been carried out. The innovation of the study is to demonstrate that the input parameters adopted in the design are correct. The analysis confirms that the GMDH algorithm gives proper results for this case study and the results are stable also when the value of each k*, characteristic of a different time hour step, varies in an admissible technical range. It was confirmed that the results obtained by using the PDA approach, analyzed by using a GMDH-type neural network, can provide higher performance sufficiency in the evaluation of WDNs.

Quantifying Hierarchical Indicators of Water Distribution Network Structure and Identifying Their Relationships with Surrogate Indicators of Hydraulic Performance

AbstractEnhancing the performance of water distribution networks (WDNs) on a day-to-day basis or under extreme disturbances is an utmost priority for utilities. Previous research has characterized ...

Comparative Analysis of Reliability Indices and Hydraulic Measures for Water Distribution Network Performance Evaluation

The performance of water distribution networks (WDNs) can be quantified by several types of hydraulic measure. In design and operation of a WDN, sufficient consideration should be given to system performance, and it would be inefficient to separately consider individual characteristics of hydraulic measures. Instead, various reliability indices have been developed and utilized to evaluate the performance of WDNs; however, deciding which index to use according to a particular WDN situation has not been investigated in sufficient depth. In this regard, this study analyzes the correlation between representative reliability indices and hydraulic measures to propose the most adequate reliability index according to the desired system performance in various situations. Specifically, six hydraulic measures representing system performance were selected from the viewpoint of redundancy, robustness, and serviceability. In addition, nine indices for estimating system reliability were classified based on theoretical backgrounds such as hydraulic, topological, entropic, and mixed approaches. The correlations between the nine indices and six measures were analyzed using 17 sample hypothetical networks with different layouts, under three water supply scenarios, and the overall evaluation results for each reliability index are presented through multi-criteria decision analysis.

Removal of heavy metals from wastewater by natural growing plants on River Nile banks in Egypt

Abstract Green remediation is a known technology that uses different types of plants to extract contaminants from the environment. This study aims to remove heavy metals from treated wastewater by using natural growing plants on River Nile banks in Egypt. Secondary treated effluent was collected from West Gerga wastewater treatment plant, located in Sohag city, Egypt. Experiments using two types of aquatic plants were carried out. They were planted individually and in combination with different densities on the secondary treated wastewater surface for 10 days' retention time to remove cadmium (Cd), nickel (Ni) and lead (Pb). It was concluded that both plants have high capabilities to remove heavy metals directly from treated wastewater. The removal efficiency of Cd and Pb was higher when they were planted together than when individually planted. A positive relationship was observed between detention time and heavy metals removal. The removal efficiency of heavy metals increased with the increase of plant density for both plant types. Also, the availability of aquatic plants and their free cost makes their use an economically attractive alternative. In addition, the removal of these plants from River Nile improves the performance of water distribution networks in Egypt.

Reliability Assessment Model of Water Distribution Networks against Fire Following Earthquake (FFE)

Fire following earthquake (FFE) is a common secondary disaster that can inflict great damage to humans. A large number of seismic resilience evaluation methods have been proposed, but few of them consider the influence of FFE. In this study, a multi-scenario simulation based model was developed to evaluate the post-disaster performance of water distribution networks (WDNs) in supplying both firefighting flow and original demand under the effect of seismic damage and FFEs. Hypothetical earthquakes were generated and the spatial–temporal distribution of FFEs was simulated by the Poisson distribution model and the Weibull distribution model. The post-disaster performance was evaluated by two types of seismic reliability metrics. The developed model was applied to a WDN currently operating in China with eight pre-determined earthquake scenarios. The results showed that the firefighting flow was concentrated in the first few hours after the earthquake. Thus, the serviceability of both original demand and firefighting flow was influenced significantly within the first few hours, while little impact was observed after the concentrated firefighting flow was delivered. The proposed model quantified the WDN’s performance under specific seismic damage and potential FFEs, and can be used for the planning, design, and maintenance of WDNs.

Improving the Performance of Water Distribution Networks Based on the Value Index in the System Dynamics Framework

This study proposes an algorithm for the improvement of water distribution networks (WDNs) performance using system dynamics. In the first part, the hydraulic and environmental performance of WDNs is investigated. The hydraulic performance is assessed based on the pressure of nodes and the flow velocity in pipes. Furthermore, using life cycle assessment, an environmental performance index is proposed to examine the environmental impacts of WDNs. Moreover, in order to evaluate the overall performance in regards to the costs, a value index in the system dynamics framework is proposed. Then, based on the developed framework, improvement strategies for a WDN are assessed by applying scenarios according to constraints and requirements of the network. The considered scenarios are as follows: (1) reducing per capita water demand of the WDN; (2) decreasing the average pressure in the WDN; (3) reducing the mean age of the system by its renewing; and (4) a combination of reducing the per capita water demand and average pressure in the WDN. The results indicate that the best solutions for increasing the value index in this network are: (a) to reduce the pressure of the pressure reducing valves (PRV) from 30 to 28 m; (b) to reduce the per capita water demand by the annual rate of 0.5% and 1% and decreasing the pressure of the PRV valves together. Therefore, it is shown how the developed algorithm is a purposeful approach for evaluating and improving the performance of WDNs based on the value index.

Solving Management Problems in Water Distribution Networks: A Survey of Approaches and Mathematical Models

Modern water distribution networks (WDNs) are complex and difficult to manage due to increased level of urbanization, varying consumer demands, ageing infrastructure, operational costs, and inadequate water resources. The management problems in such complex networks may be classified into short-term, medium-term, and long-term, depending on the duration at which the problems are solved or considered. To address the management problems associated with WDNs, mathematical models facilitate analysis and improvement of the performance of water infrastructure at minimum operational cost, and have been used by researchers, water utility managers, and operators. This paper presents a detailed review of the management problems and essential mathematical models that are used to address these problems at various phases of WDNs. In addition, it also discusses the main approaches to address these management problems to meet customer demands at the required pressure in terms of adequate water quantity and quality. Key challenges that are associated with the management of WDNs are discussed. Also, new directions for future research studies are suggested to enable water utility managers and researchers to improve the performance of water distribution networks.

Increasing Performance of Water Distribution Network by Using Pressure Management and Database Integration

AbstractThe performance of a water distribution networks (WDN) varies according to various factors such as physical, operational, and environmental and should be monitored to reduce and control the...

Improving Consumer Satisfaction in Water Distribution Networks Through Optimal Use of Auxiliary Tanks (A Case Study of Kashan City, Iran)

Temporal and spatial variations in pressure may lead to consumer dissatisfaction and distrust of water distribution networks when it comes to reliable performance. Pressure management is a set of programs and operations conducted in water distribution networks to adjust the pressure. Constructing new auxiliary tanks in proper locations at the best height for the area they serve minimizes the pressure fluctuations. Additionally, chlorine is often injected in the reservoirs and tanks to improve the water quality. The goal of this research was to improve the condition of the network by adding auxiliary tanks with appropriate locations, heights and chlorine concentration. An optimization model is prepared to optimize consumer satisfaction, water quality and the relevant costs as objective functions. The performance of the models are evaluated by a selected case study; and the objectives are optimized in three scenarios. Using the proposed model in a water distribution network, a trade-off diagram of reliability and costs is obtained, that lets the decision makers select the proper options considering the available fund. A new indicator, the consumer satisfaction index, is also proposed as a way to evaluate the performance of water distribution networks.

Investigating the management performance of disinfection analysis of water distribution networks using data mining approaches

Chlorination, the basic treatment utilized for drinking water sources, is widely used for water disinfection and pathogen elimination in water distribution networks. Thereafter, the proper prediction of chlorine consumption is of great importance in water distribution network performance. In this respect, data mining techniques-which have the ability to discover the relationship between dependent variable(s) and independent variables-can be considered as alternative approaches in comparison to conventional methods (e.g., numerical methods). This study examines the applicability of three key methods, based on the data mining approach, for predicting chlorine levels in four water distribution networks. ANNs (artificial neural networks, including the multi-layer perceptron neural network, MLPNN, and radial basis function neural network, RBFNN), SVM (support vector machine), and CART (classification and regression tree) methods were used to estimate the concentration of residual chlorine in distribution networks for three villages in Kerman Province, Iran. Produced water (flow), chlorine consumption, and residual chlorine were collected daily for 3years. An assessment of the studied models using several statistical criteria (NSC, RMSE, R2, and SEP) indicated that, in general, MLPNN has the greatest capability for predicting chlorine levels followed by CART, SVM, and RBF-ANN. Weaker performance of the data-driven methods in the water distribution networks, in some cases, could be attributed to improper chlorination management rather than the methods' capability.

Smart Solution to Improve Water-energy Nexus for Water Supply Systems

In the last years, there has been a great interest in the complex relations between energy and water, known as the Water-Energy Nexus [1]. Natural resources, such as energy and water, enable economy growth and support quality of life. The Water-Energy Nexus is considered as one of the most important multidisciplinary challenges [2] that the global growing water market [3] has to face in the forthcoming years. Currently, many water systems are not managed sustainably enough. Water Utilities face other challenges, such as infrastructure aging and poor cost-recovery, leading to a lack of finance for O&M (Operation and Maintenance). Energy is required in all stages of water production and distribution, from pumping and treatment to transportation. Energy costs are a top-of-mind concern for water utilities, regardless of geography, size and level of water network efficiency [4]. On the other hand, Water Utilities are having a hard time to either improve their services or expand their network to unserved neighborhoods in developing countries.The current trend of water transmission system to the creation of DMAs (District Metered Areas) offers great possibilities of non-structural solutions that use existing data and transform them into useful information to support decision making. The Smart Metering and the use of large amounts of data from a network enhance the use of software for decision support, but it is not the only way. Smart Solutions can also be applied to networks with less recorded data, which would enhance operators’ knowledge to these data, turn them into useful information for decision-making either for the operation or the maintenance and network design. In this scope, a Smart Solution is presented. It is developed combining key factors of the energy consumption and the water supply into water networks management to obtain improvements from both water and energy fields. This non-structural solution increases resource efficiency and environmental performance of water distribution networks by using data acquisition and geographical visualization (real time & historical), weather and water demand forecasting, detection of networks events and hydraulic simulation of the network, and finally through a decision support system based on machine learning (pattern recognition and business rules techniques).As a conclusion, a non-structural solution for the Nexus issues can have a great impact on several matters (climate change, carbon footprint, WUs balance sheets, and water losses) with reasonable investment either in smart metering or networks with only a few sensors measuring.

Integrated performance assessment model for water distribution networks

The American infrastructure report card in 2013 rated the US water system infrastructure with grade of ‘D’. The Canadian infrastructure report card in 2012 stated that around 15.4% of Canada’s water infrastructure has a condition of fair to very poor. Thus, there is a critical need to develop efficient inspection, maintenance and rehabilitation plans for water distribution networks. However, such plans require an assessment tool to evaluate the performance and condition of water distribution networks. Therefore, the main purpose of this paper is to develop an integrated performance assessment model for water distribution networks. Two modules were developed to assess the performance of water pipelines and accessories, respectively. A third module was developed to assess the performance of water segments that includes pipelines and accessories. Moreover, a fourth module was built to assess the performance of each sub-network and the entire network based on the segments’ connection type using a reliability-based approach. To assess the performance of the water distribution network, the critical factors affecting its pipelines and accessories were identified and studied. The fuzzy analytic network process technique was used to obtain the importance weights of the identified factors.

Performance Index for Water Distribution Networks under Multiple Loading Conditions

AbstractPrevious studies have naturally related water distribution network performance to the ability to deliver sufficient pressure and flow. The present paper emphasizes that performance also depends on the efficiency of delivering these requirements. Accordingly, an efficiency-based performance index is proposed. It is the geometric average of four performance metrics: reliability, vulnerability, resilience, and connectivity. These are themselves based on the energy efficiency, hydraulic capacity, and structural ability of the system to deliver water under a range of conditions. The metrics are applied to two example networks and variations of these, enabling the assessment of their relevance, their sensitivity to system changes, and permitting a comparison to existing metrics. Variations represent different redundancy increasing strategies, recognized for improving performance. The proposed performance index generally follows a similar trend as the previous indices, increasing with network pressure. N...

Optimum reliable operation of water distribution networks by minimising energy cost and chlorine dosage

In recent decades much attention has been paid to optimal operation of water distribution networks (WDNs). In this regard, the system operation costs, including energy and disinfection chemicals, as well as system reliability should be simultaneously considered in system performance optimisation, to provide the minimum required level of performance in failure condition and to manage economic limitations. In this study, multi-objective optimisation of water distribution network performance in 3 different scenarios was considered. In these scenarios the effects of time-dependent chlorine injection and pump speed, as well as different combinations of objective functions for minimising energy and disinfection costs and for maximising hydraulic reliability and quality-based reliability are incorporated. As the optimisation method, a multi-objective ant colony optimisation (ACO) algorithm was used because of its high efficiency. For better managing the hydraulic behaviour and water quality in the WDN, considering temporal variations of demand, it is suggested to use variable speed pumps (VSP) as well as to inject chlorine at a variable rate. Application of VSP and time-dependent chlorine injection results in improvements such as reduction in energy and disinfection costs, and decrease in disinfection costs in application of HDSM (head-driven simulation method). In HDSM simulation of WDN, a decrease in hydraulic reliability because of shortages in water supply can be mitigated through extra chlorine injection and increase in quality-based reliability. To deal with this challenge, it is recommended to satisfy the hydraulic reliability first and then to evaluate the quality reliability. Furthermore it is necessary to modify the hydraulic reliability relationship to incorporate different components of the WDN other than pumps. This will provide more reliable results for evaluation of the system performance.Keywords: multi-objective optimisation, aco algorithm, energy cost, disinfection costs, hydraulic reliability, quality reliability