scholarly journals Enhanced Water Age Performance Assessment in Distribution Networks

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2574
Author(s):  
Laura Monteiro ◽  
Ricardo Algarvio ◽  
Dídia Covas
Keyword(s):  
Water Quality ◽  
Performance Assessment ◽  
Reference Values ◽  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Operating Conditions ◽  
Water Age ◽  
Major Improvement ◽  
Age Limits

Water age is frequently used as a surrogate for water quality in distribution networks and is often included in modelling and optimisation studies, though there are no reference values or standard performance functions for assessing the network behaviour regarding water age. This paper presents a novel methodology for obtaining enhanced system-specific water age performance assessment functions, tailored for each distribution network. The methodology is based on the establishment of relationships between the chlorine concentration at the sampling nodes and simulated water age. The proposed methodology is demonstrated through application to two water distribution systems in winter and summer seasons. Obtained results show a major improvement in comparison with those obtained by published performance functions, since the water age limits of the performance functions used herein are tailored to the analysed networks. This demonstrates that the development of network-specific water age performance functions is a powerful tool for more robustly and reliably defining water age goals and evaluating the system behaviour under different operating conditions.

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.

Improving water age estimation in a drinking water distribution network by field study and digital modeling

2021 ◽  
Author(s):  
Jon Kristian Rakstang ◽  
Michael B. Waak ◽  
Marius M. Rokstad ◽  
Cynthia Hallé
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Network Model ◽  
Age Estimation ◽  
Water Distribution ◽  
Distribution Network ◽  
Distribution Networks ◽  
Plate Count ◽  
Water Age ◽  
Drinking Water Distribution

<p>Municipal drinking water distribution networks are complex and dynamic systems often spanning many hundreds of kilometers and serving thousands of consumers. Degradation of water quality within a distribution network can be associated to water age (i.e., time elapsed after treatment). Norwegian distribution networks often consist of an intricate combination of pressure zones, in which the transport path(s) between source and consumer is not easily ascertained. Water age is therefore poorly understood in many Norwegian distribution networks. In this study, simulations obtained from a water network model were used to estimate water age in a Norwegian municipal distribution network. A full-scale tracer study using sodium chloride salt was conducted to assess simulation accuracy. Water conductivity provided empirical estimates of salt arrival time at five monitoring stations. These estimates were consistently higher than simulated peak arrival times. Nevertheless, empirical and simulated water age correlated well, indicating that additional network model calibration will improve accuracy. Subsequently, simulated mean water age also correlated strongly with heterotrophic plate count (HPC) monitoring data from the distribution network (Pearson’s R= 0.78, P= 0.00046), indicating biomass accumulation during distribution—perhaps due to bacterial growth or biofilm interactions—and illustrating the importance of water age for water quality. This study demonstrates that Norwegian network models can be calibrated with simple and cost-effective salt tracer studies to improve water age estimates. Improved water age estimation will increase our understanding of water quality dynamics in distribution networks. This can, through digital tools, be used to monitor and control water age, and its impact on biogrowth in the network.</p>

Velocity-based self-cleaning residential drinking water distribution systems

2009 ◽  
Vol 9 (6) ◽  
pp. 635-641 ◽  
Author(s):  
J. H. G. Vreeburg ◽  
E. J. M Blokker ◽  
P. Horst ◽  
J. C. van Dijk
Keyword(s):  
Water Quality ◽  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Drinking Water Distribution Systems ◽  
Total Length ◽  
Drinking Water Distribution ◽  
Total Investment ◽  
Close Cooperation ◽  
Modern Building

Resuspension of accumulated particles in residential networks is the main cause for customers to complain to the water company about the water quality. Preventing the particles from accumulating in these networks can be achieved by high velocities in pipes. Adding this velocity criterion to the conventional design criteria leads to a branched lay out of distribution networks, that perform better with respect to water quality, continuity of supply and investment costs. In close cooperation with fire brigades the conventional fire flow requirements were challenged. Based on modern building codes, it proved possible to reduce the capacity of fire-hydrants to 8.3 l/s (30 m3/h) in newly built areas. Six years after the introduction of the velocity criterion the characteristics of the newly laid networks have changed resulting in smaller diameter pipes and reduced length of networks. The amount of 100/110 mm pipes have dropped from 55% of the total length to 45% of total length. The total investment costs for new networks have dropped by 20% in the Netherlands.

scholarly journals Intelligent system for control of water distribution networks

2017 ◽  
Vol 18 (4) ◽  
pp. 1270-1281 ◽  
Author(s):  
Emânuel Guerra Barros Filho ◽  
Laís Régis Salvino ◽  
Saulo de Tarso Marques Bezerra ◽  
Moisés Menezes Salvino ◽  
Heber Pimentel Gomes
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Research Study ◽  
Intelligent System ◽  
Rotation Speed ◽  
Electricity Consumption ◽  
Distribution Networks ◽  
Maximum Error ◽  
Operating Conditions ◽  
Water Distribution Networks

Abstract The objective of this research study was the development of an intelligent system based on artificial neural networks for water distribution networks that operate with parallel pumps. The purpose of the system is to automate the process and to define the operating state of the electric motors (on, off or with partial rotation speed). The intelligent system developed is generic, which allows the application of its control structure in similar processes, and it was applied in an experimental setup that simulates a real water supply system. The performance of the network was tested experimentally under different operating conditions, including in the presence of disturbances. The settling time was, in all experiments, less than 30 seconds, the tests did not show overshoot and the maximum error was 2.9%. Results showed excellent performance in terms of pressure regulation, and it is hoped that the controller can be successfully implemented in real water distribution systems, in order to reduce water and electricity consumption, decrease maintenance costs and increase the reliability of operating procedures.

scholarly journals Assessment of water quality modelling capabilities of EPANET multiple species and pressure-dependent extension models

2013 ◽  
Vol 13 (4) ◽  
pp. 1161-1166 ◽  
Author(s):  
Alemtsehay G. Seyoum ◽  
Tiku T. Tanyimboh ◽  
Calvin Siew
Keyword(s):  
Water Quality ◽  
Distribution Systems ◽  
Operating Conditions ◽  
Quality Analysis ◽  
Future Research ◽  
Operating Pressure ◽  
Quality Model ◽  
Water Age ◽  
First Order ◽  
Multiple Species

The need for accurately predicting water quality through models has increasingly been crucial in meeting rigorous standards and customer expectations. There are several endeavours on developing robust water quality models for water distribution systems. In this paper, two variants of the EPANET 2 water quality model have been assessed to inform future research. The models are the multiple species extension EPANET-MSX and the pressure-dependent extension EPANET-PDX. Water quality analysis was conducted on a hypothetical network considering various operating pressure conditions. Different kinetic models were employed to simulate water quality. First order, limited first order and zero order models were used for predicting chlorine residual, disinfection by-products (DBPs) and water age respectively. Generally, EPANET-MSX and EPANET-PDX provided identical water quality results for normal operating conditions with adequate pressure but different results for pressure-deficient networks. Also, a parallel first order model with fast and slow reacting components was used for chlorine decay and DBPs using the EPANET-MSX model for a network operating under normal pressure conditions.

scholarly journals Comparison Between Diffusive and Advective Approach in Quality Analysis of a Real Distribution Network

10.29007/chxk ◽  
2018 ◽  
Author(s):  
Stefania Piazza ◽  
E.J. Mirjam Blokker ◽  
Gabriele Freni ◽  
Valeria Puleo ◽  
Mariacrocetta Sambito
Keyword(s):  
Water Quality ◽  
Turbulent Flows ◽  
Urban Areas ◽  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Network ◽  
Water Distribution Systems ◽  
Distribution Networks ◽  
Quality Analysis ◽  
Real Distribution

In recent years, the evaluation of water quality in distribution systems has generated enormous interest in the scientific community due to the increasing concentration of population in urban areas and frequent issues connected with supply water quality. Following the wave of bioterrorism subsequent the events of September 11th 2001, a need can be foreseen to seek adequate preventive measures to deal with contamination in water distribution systems that may be related to the accidental contamination and deliberate injection of toxic agents of any origin in the distribution networks. Therefore, it is very important to create a sensor system that detects contamination events in real time, while maintaining the reliability and efficiency of the measurements, limiting the cost of the instrumentation. A reliable monitoring system, for this kind of problems, cannot be deployed without realistic modelling support. The current state-of-the-art in water distribution systems analysis usually adopt a simplified approach to water quality modelling, neglecting dispersion and diffusion and considering simplified reaction kinetics. Even if such simplifications are commonly acceptable in fully turbulent flows, they may take to relevant errors in transition flows with low velocity thus taking to unreliable interpretation of the contamination in complex networks. The present paper aims to compare different modelling approaches to the evaluation of contaminant dispersion in two distribution networks: one laboratory network in which contamination experiments were carried out in a controlled environment (Enna, Italy) and a full-scale real distribution network (Zandvoort, Netherlands).

scholarly journals A Numerical Investigation into the PAT Hydrodynamic Response to Impeller Rotational Speed Variation

2021 ◽  
Vol 13 (14) ◽  
pp. 7998
Author(s):  
Maxime Binama ◽  
Kan Kan ◽  
Hui-Xiang Chen ◽  
Yuan Zheng ◽  
Daqing Zhou ◽  
...  
Keyword(s):  
Rotational Speed ◽  
Distribution Systems ◽  
Water Distribution ◽  
Production Efficiency ◽  
Operating Conditions ◽  
Energy Regulation ◽  
Speed Increase ◽  
Energy Field ◽  
Long Run ◽  
Study Results

The utilization of pump as turbines (PATs) within water distribution systems for energy regulation and hydroelectricity generation purposes has increasingly attracted the energy field players’ attention. However, its power production efficiency still faces difficulties due to PAT’s lack of flow control ability in such dynamic systems. This has eventually led to the introduction of the so-called “variable operating strategy” or VOS, where the impeller rotational speed may be controlled to satisfy the system-required flow conditions. Taking from these grounds, this study numerically investigates PAT eventual flow structures formation mechanism, especially when subjected to varying impeller rotational speed. CFD-backed numerical simulations were conducted on PAT flow under four operating conditions (1.00 QBEP, 0.82 QBEP, 0.74 QBEP, and 0.55 QBEP), considering five impeller rotational speeds (110 rpm, 130 rpm, 150 rpm, 170 rpm, and 190 rpm). Study results have shown that both PAT’s flow and pressure fields deteriorate with the machine influx decrease, where the impeller rotational speed increase is found to alleviate PAT pressure pulsation levels under high-flow operating conditions, while it worsens them under part-load conditions. This study’s results add value to a thorough understanding of PAT flow dynamics, which, in a long run, contributes to the solution of the so-far existent technical issues.

scholarly journals Modeling Bacterial Regrowth and Trihalomethane Formation in Water Distribution Systems

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 463
Author(s):  
Gopinathan R. Abhijith ◽  
Leonid Kadinski ◽  
Avi Ostfeld
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Mechanistic Model ◽  
Water Distribution Systems ◽  
Sensitivity Study ◽  
Operating Conditions ◽  
Growth Rate Constant ◽  
Model Parameters ◽  
Bacterial Regrowth ◽  
The Impact

The formation of bacterial regrowth and disinfection by-products is ubiquitous in chlorinated water distribution systems (WDSs) operated with organic loads. A generic, easy-to-use mechanistic model describing the fundamental processes governing the interrelationship between chlorine, total organic carbon (TOC), and bacteria to analyze the spatiotemporal water quality variations in WDSs was developed using EPANET-MSX. The representation of multispecies reactions was simplified to minimize the interdependent model parameters. The physicochemical/biological processes that cannot be experimentally determined were neglected. The effects of source water characteristics and water residence time on controlling bacterial regrowth and Trihalomethane (THM) formation in two well-tested systems under chlorinated and non-chlorinated conditions were analyzed by applying the model. The results established that a 100% increase in the free chlorine concentration and a 50% reduction in the TOC at the source effectuated a 5.87 log scale decrement in the bacteriological activity at the expense of a 60% increase in THM formation. The sensitivity study showed the impact of the operating conditions and the network characteristics in determining parameter sensitivities to model outputs. The maximum specific growth rate constant for bulk phase bacteria was found to be the most sensitive parameter to the predicted bacterial regrowth.

scholarly journals Sectorization for Water Distribution Systems with Multiple Sources: A Performance Indices Comparison

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 131
Author(s):  
Jezabel D. Bianchotti ◽  
Melina Denardi ◽  
Mario Castro-Gama ◽  
Gabriel D. Puccini
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Performance Criteria ◽  
Performance Indices ◽  
Multiple Sources ◽  
Multiobjective Problems ◽  
Open Questions ◽  
Minimum Number ◽  
And Performance

Sectorization is an effective technique for reducing the complexities of analyzing and managing of water systems. The resulting sectors, called district metering areas (DMAs), are expected to meet some requirements and performance criteria such as minimum number of intervention, pressure uniformity, similarity of demands, water quality and number of districts. An efficient methodology to achieve all these requirements together and the proper choice of a criteria governing the sectorization is one of the open questions about optimal DMAs design. This question is addressed in this research by highlighting the advantages of three different criteria when applied to real-word water distribution networks (WDNs). To this, here it is presented a two-stage approach for optimal design of DMAs. The first stage, the clustering of the system, is based on a Louvain-type greedy algorithm for the generalized modularity maximization. The second stage, the physical dividing of the system, is stated as a two-objective optimization problem that utilises the SMOSA version of simulated annealing for multiobjective problems. One objective is the number of isolation valves whereas for the second objective three different performance indices (PIs) are analyzed and compared: (a) standard deviation, (b) Gini coefficient and (c) loss of resilience. The methodology is applied to two real case studies where the first two PIs are optimized to address similar demands among DMAs. The results demonstrate that the proposed method is effective for sectorization into independent DMAs with similar demands. Surprisingly, it found that for the real studied systems, loss of resilience achieves better performance for each district in terms of pressure uniformity and demand similarity than the other two specific performance criteria.

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