scholarly journals Pressure Regulation vs. Water Aging in Water Distribution Networks

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1323 ◽  
Author(s):  
Menelaos Patelis ◽  
Vasilis Kanakoudis ◽  
Anastasia Kravvari
Keyword(s):  
Water Distribution ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
High Water ◽  
Pressure Regulation ◽  
Water Age ◽  
Hydraulic Simulation ◽  
Annual Water ◽  
Winter Time ◽  
The Impact

In this paper, the effects of pressure regulation in a water distribution network (WDN) are being examined. Quality is hammered the most when pressure is reduced in a WDN and this occurs due to the increase in the age of water flowing inside the network pipes (water age is actually the total time the water remains inside the pipes before reaching the customer’s tap). Kos town WDN is used as the case study network. Kos town is the capital of the homonymous Greek island, among the most famous and popular of the Greek islands. The specific WDN is quite typical but very interesting, as it is extended along the seafront. The network’s hydraulic simulation model was developed through the WaterCad V8i software. As Kos experiences too high-water demand peaks and lows during summer and winter time, respectively, its WDN has already been thoroughly studied, in order to regulate the pressure and reduce its annual water loss rates. Nevertheless, these scenarios have never been examined regarding the impact on water quality. In the current study, the division of the WDN in District Metered Areas (DMAs) and the use of a Pressure Reducing Valve (PRV) in the entering node of each DMA are being evaluated in terms of water age. Additionally, a swift optimization process takes place to produce different DMAs’ borders, based on the criteria of minimum nodal water age, instead of optimal pressure. Different scenarios were tested on the calibrated and validated hydraulic model of Kos town WDN.

scholarly journals Assessing the Impact of DMAs and the Use of Boosters on Chlorination in a Water Distribution Network in Greece

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2141
Author(s):  
Stavroula Tsitsifli ◽  
Vasilis Kanakoudis
Keyword(s):  
Water Distribution ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Assessment Process ◽  
Water Volume ◽  
Pressure Management ◽  
Water Age ◽  
Chlorination Process ◽  
Management Measures ◽  
The Impact

Disinfection is one of the most important water treatment processes as it inactivates pathogens providing safe drinking water to the consumers. A fresh-water distribution network is a complex system where constant monitoring of several parameters and related managerial decisions take place in order for the network to operate in the most efficient way. However, there are cases where some of the decisions made to improve the network’s performance level, such as reduction of water losses, may have negative impacts on other significant operational processes such as the disinfection. In particular, the division of a water distribution network into district metered areas (DMAs) and the application of various pressure management measures may impact the effectiveness of the water chlorination process. Two operational measures are assessed in this paper: (a) the use of inline chlorination boosters to achieve more efficient chlorination; and (b) how the DMAs formation impacts the chlorination process. To achieve this, the water distribution network of a Greek town is chosen as a case study where several scenarios are being thoroughly analyzed. The assessment process utilizes the network’s hydraulic simulation model, which is set up in Watergems V8i software, forming the baseline to develop the network’s water quality model. The results proved that inline chlorination boosters ensure a more efficient disinfection, especially at the most remote parts/nodes of the network, compared to conventional chlorination processes (e.g., at the water tanks), achieving 100% safe water volume and consuming almost 50% less chlorine mass. DMAs’ formation results in increased water age values up to 8.27%, especially at the remote parts/nodes of the network and require more time to achieve the necessary minimum effective chlorine concentration of 0.2 mg/L. However, DMAs formation and pressure management measures do not threaten the chlorination’s efficiency. It is important to include water age and residual chlorine as criteria when optimizing water pressure and the division of DMAs.

scholarly journals Optimal Placement of Pressure Gauges for Water Distribution Networks Using Entropy Theory Based on Pressure Dependent Hydraulic Simulation

Entropy ◽  
2018 ◽  
Vol 20 (8) ◽  
pp. 576 ◽  
Author(s):  
Do Yoo ◽  
Dong Chang ◽  
Yang Song ◽  
Jung Lee
Keyword(s):  
Water Distribution ◽  
Pressure Gauge ◽  
Distribution Networks ◽  
Entropy Method ◽  
Water Distribution Networks ◽  
Optimal Placement ◽  
Hydraulic Simulation ◽  
Priority Order ◽  
The Impact ◽  
Pressure Driven

This study proposed a pressure driven entropy method (PDEM) that determines a priority order of pressure gauge locations, which enables the impact of abnormal condition (e.g., pipe failures) to be quantitatively identified in water distribution networks (WDNs). The method developed utilizes the entropy method from information theory and pressure driven analysis (PDA), which is the latest hydraulic analysis method. The conventional hydraulic approach has problems in determining the locations of pressure gauges, attributable to unrealistic results under abnormal conditions (e.g., negative pressure). The proposed method was applied to two benchmark pipe networks and one real pipe network. The priority order for optimal locations was produced, and the result was compared to existing approach. The results of the conventional method show that the pressure reduction difference of each node became so excessive, which resulted in a distorted distribution. However, with the method developed, which considers the connectivity of a system and the influence among nodes based on PDA and entropy method results, pressure gauges can be more realistically and reasonably located.

scholarly journals Improved Hydraulic Simulation of Valve Layout Effects on Post-Earthquake Restoration of a Water Distribution Network

2020 ◽  
Vol 12 (8) ◽  
pp. 3492
Author(s):  
Jeongwook Choi ◽  
Doosun Kang
Keyword(s):  
Water Distribution ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Seismic Damage ◽  
Hydraulic Analysis ◽  
Hydraulic Simulation ◽  
Restoration Process ◽  
Restoration Strategies ◽  
The Impact ◽  
Pressure Driven Analysis

To restore water pipes damaged by earthquakes, it is common to block the water flow by closing the associated shut-off valves. In this process, water supply suspension in the area connected to the isolated pipes is inevitable, which decreases the serviceability of the water distribution network (WDN). In this study, we identified the impact of valve layout (i.e., number and location) on system serviceability during a seismic damage restoration process. By conducting a pressure-driven-analysis (PDA) using EPANET 3.0, a more realistic hydraulic analysis could be carried out under the seismically damaged condition. Furthermore, by considering the valve-controlled segment in the hydraulic simulation, a more realistic water suspension area was determined, and efficient seismic damage restoration strategies were identified. The developed model was implemented on a WDN to demonstrate the effect of valve layout on the post-earthquake restoration process. Finally, effective restoration strategies were suggested for the application network.

scholarly journals Generating Scenarios of Cross-Correlated Demands for Modelling Water Distribution Networks

2019 ◽  
Author(s):  
Roberto Magini ◽  
Maria Antonietta Boniforti ◽  
Roberto Guercio
Keyword(s):  
Water Distribution ◽  
Scaling Laws ◽  
Numerical Procedure ◽  
Latin Hypercube Sampling ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Numerical Approach ◽  
Hydraulic Simulation ◽  
Whole Number ◽  
Entire Network

A numerical approach for generating a limited number of water demand scenarios and estimating their occurrence probabilities in a Water Distribution Network (WDN) is proposed. This approach makes use of the demand scaling laws in order to consider the natural variability and spatial correlation of nodal consumptions. The scaling laws are employed to determine the statistics of nodal consumption as a function of the number of users and the main statistical features of the unitary user's demand. Besides, consumption at each node is considered to follow a Gamma probability distribution. A high number of groups of cross-correlated demands, i.e., scenarios, for the entire network were generated using Latin Hypercube Sampling (LHS) and the numerical procedure proposed by Iman and Conover. The Kantorovich distance is used to reduce the number of scenarios and estimate their corresponding probabilities, while keeping the statistical information on nodal consumptions. By hydraulic simulation, the whole number of generated demand scenarios was used to obtain a corresponding number of pressure scenarios on which the same reduction procedure was applied. The probabilities of the reduced scenarios of pressure were compared with the corresponding probabilities of demand.

scholarly journals Optimizing the Formation of DMAs in a Water Distribution Network Applying Geometric Partitioning (GP) and Gaussian Mixture Models (GMMs)

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 601 ◽  
Author(s):  
Stavroula Chatzivasili ◽  
Katerina Papadimitriou ◽  
Vasilis Kanakoudis ◽  
Menelaos Patelis
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Gaussian Mixture ◽  
Optimal Placement ◽  
Water Age ◽  
Optimal Separation ◽  
Geometric Partitioning

In the last three decades, the need of achieving a reliable water distribution system has become more eminent for both the consumer’s satisfaction and the efficient management of water sources. The purpose of this paper is to provide an optimal separation of a water distribution network (WDN) into District Metered Areas (DMAs) in order to ensure that the delivered water is of proper age and pressure. At first, the water distribution network is divided into smaller areas via the method of Geometric Partitioning, which is based on Recursive Coordinate Bisection (RCB). Subsequently, Gaussian Mixture Modelling (GMM) solution is applied, obtaining an optimal placement of isolation valves and separation of the WDN into DMAs. The performance of the proposed system is evaluated on two different networks and is compared against the Genetic Algorithm (GA) tool, constituting a very promising approach, especially for sizeable water distribution networks due to the diminished running time and the noteworthy reduction of pressure and water age.

scholarly journals Identification of Critical Pipes Using a Criticality Index in Water Distribution Networks

2019 ◽  
Vol 9 (19) ◽  
pp. 4052 ◽  
Author(s):  
Malvin S. Marlim ◽  
Gimoon Jeong ◽  
Doosun Kang
Keyword(s):  
Water Distribution ◽  
Critical Infrastructure ◽  
Economic Value ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Simulation Approach ◽  
Water Age ◽  
Water Service ◽  
Critical Elements ◽  
Value Loss

A water distribution network (WDN) is a critical infrastructure that must be maintained, ensuring a proper water supply to widespread customers. A WDN consists of various components, such as pipes, valves, pumps, and tanks, and these elements interact with each other to provide adequate system performance. If the elements fail due to internal or external interruptions, this may adversely impact water service to different degrees depending on the failed elements. To determine an appropriate maintenance priority, the critical elements need to be identified and mapped in the network. To identify and prioritize the critical elements (here, we focus on the pipes only) in the WDN, an element-based simulation approach is proposed, in which all the composing pipes of the WDN are reviewed one at a time. The element-based criticality is measured using several criticality indexes that are newly proposed in this study. The proposed criticality indexes are used to quantify the impacts of element failure to water service degradation. Here, four criticality indexes are developed: supply shortage (SS), economic value loss (EVL), pressure decline (PD), and water age degradation (WAD). Each of these indexes measures different aspects of the consequences, specifically social, economic, hydraulic, and water quality, respectively. The separate values of the indexes from all pipes in a network are then combined into a singular criticality value for assessment. For demonstration, the proposed approach is applied to four real WDNs to identify and prioritize the critical pipes. The proposed element-based simulation approach can be used to identify the critical components and setup maintenance scheduling of WDNs for preparedness of failure events.

scholarly journals Impact of variable speed pumps on water quality in distribution systems

Water SA ◽  
2018 ◽  
Vol 44 (3 July) ◽  
Author(s):  
Moustafa S Darweesh
Keyword(s):  
Water Quality ◽  
Distribution Systems ◽  
Water Distribution ◽  
Average Rate ◽  
Extended Period ◽  
Distribution Networks ◽  
Residual Chlorine ◽  
Variable Speed ◽  
Water Age ◽  
The Impact

Water quality has become a prominent issue in the study of water distribution networks. Variable speed pumps (VSPs) can control and improve the performance of water distribution systems. However, they may have effects on the water quality. The objective of this study was to investigate the impact of VSPs on water quality. The EPANET water quality simulator was applied for modelling water age and chlorine residual in a distribution network. In addition, intrusion of an active contaminant and analysis of leakage effects on residual chlorine concentration were performed through extended period simulations. Results indicate that VSPs may have negative impacts on water quality, including increased water age during low consumption times, and reduced disinfectant residuals at peak hours. In addition, the average rate of chlorine decay for fixed speed pumps (57%) is higher than that for VSPs (54%) when a conservative contaminant (sewage water) is considered.

scholarly journals Generating Scenarios of Cross-Correlated Demands for Modelling Water Distribution Networks

2019 ◽  
Author(s):  
Roberto Magini ◽  
Maria Antonietta Boniforti ◽  
Roberto Guercio
Keyword(s):  
Water Distribution ◽  
Scaling Laws ◽  
Numerical Procedure ◽  
Latin Hypercube Sampling ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Reduction Procedure ◽  
Hydraulic Simulation ◽  
Whole Number ◽  
Entire Network

This paper presents a methodology for the generation of a limited and representative number of water demand scenarios, taking into account the natural variability and spatial correlation of nodal consumption in a Water Distribution Network (WDN), and estimates their corresponding occurrence probabilities. Scaling laws are used to evaluate the statistics of water consumption at each node as a function of the number of users, considering the main statistical features of the unitary user's demand. Besides, consumption at each node is considered to follow a Gamma probability distribution. A high number of groups of cross-correlated demands, i.e. scenarios, for the entire network were generated using Latin Hypercube Sampling (LHS) and the numerical procedure proposed by Iman and Conover. The Kantorovich distance is used to reduce the number of scenarios and estimate their corresponding probabilities, while keeping the statistical information on nodal consumptions. By hydraulic simulation, the whole number of generated demand scenarios was used to obtain a corresponding number of pressure scenarios on which the same reduction procedure was applied. The probabilities of the reduced scenarios of pressure were compared with the corresponding probabilities of demand.

scholarly journals Generating Scenarios of Cross-Correlated Demands for Modelling Water Distribution Networks

2019 ◽  
Author(s):  
Roberto Magini ◽  
Maria Antonietta Boniforti ◽  
Roberto Guercio
Keyword(s):  
Water Distribution ◽  
Scaling Laws ◽  
Numerical Procedure ◽  
Latin Hypercube Sampling ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Hydraulic Simulation ◽  
Whole Number ◽  
User Demand ◽  
Entire Network

This paper presents a methodology for the generation of a limited and representative number of water demand scenarios, taking into account the natural variability and spatial correlation of nodal consumption in a Water Distribution Network (WDN), and estimates their corresponding occurrence probabilities. Scaling laws are used to evaluate the statistics of water consumption at each node as a function of the number of users, considering the main statistical features of the unitary user' demand. Besides, consumption at each node is considered to follow a Gamma probability distribution. A high number of groups of cross-correlated demands, i.e. scenarios, for the entire network were generated using Latin Hypercube Sampling (LHS) and the numerical procedure proposed by Iman and Conover. The Kantorovich distance is used to reduce the number of scenarios and estimate their corresponding probabilities, while keeping the statistical information on nodal consumptions. By hydraulic simulation, the whole number of generated demand scenarios was used to obtain a corresponding number of pressure scenarios on which the same reduction procedure was applied. The probabilities of the reduced scenarios of pressure were compared with the corresponding probabilities of the demand.

scholarly journals The Impact of Pressure Management Techniques on the Water Age in an Urban Pipe Network—The Case of Kos City Network

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 699 ◽  
Author(s):  
Anastasia Kravvari ◽  
Vasilis Kanakoudis ◽  
Menelaos Patelis
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Optimization Criterion ◽  
Maximum Pressure ◽  
Pressure Management ◽  
Water Age ◽  
City Water ◽  
The Impact

The goal of this article is to study the impact that pressure management in distribution systems has, on the quality of the supplied water in terms of its water age, using the water distribution network of Kos city, capital of Kos Island in Greece was used as the case study network. This was achieved through network simulation using the Watercad V8i software, followed by the division of the network in district metered areas (DMA) and the placement of pressure reducing valves (PRV) in the entering nodes of each DMA. Research aimed also to optimize DMAs’ borders using the water age as the optimization criterion, instead of maximum pressure reduction. Different scenarios were tested on the calibrated and validated hydraulic model of Kos city water distribution network.

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