scholarly journals Technical note: Graph theory-based heuristics to aid in the implementation of optimized drinking water network sectorization

2022 ◽  
Author(s):  
Marius Møller Rokstad ◽  
Karel Antonie van Laarhoven

Abstract. Drinking water distribution networks form an essential part of modern-day critical infrastructure. Sectorizing a network into district metered areas is a key technique for pressure management and water loss reduction. Sectorizing an existing network from scratch is, however, an exceedingly complex design task that designs in a well-studied general mathematical problem. Numerical optimization techniques such as evolutionary algorithms can be used to search for near-optimal solutions to such problems, but doing so within a reasonable timeframe remains an ongoing challenge. In this work, we introduce two heuristic tricks that use information of the network structure and information of the operational requirements of the drinking water distribution network to modify the basic evolutionary algorithm used to solve the general problem. These techniques not only reduce the time required to find good solutions, but also ensure that these solutions better match the requirements of drinking water practice. Both techniques were demonstrated by applying them in the sectorization of the actual distribution network of a large city.

2021 ◽  
Author(s):  
Jon Kristian Rakstang ◽  
Michael B. Waak ◽  
Marius M. Rokstad ◽  
Cynthia Hallé

<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>


2018 ◽  
Author(s):  
Karel van Laarhoven ◽  
Ina Vertommen ◽  
Peter van Thienen

Abstract. Genetic algorithms can be a powerful tool for the automated design of optimal drinking water distribution networks. Fast convergence of such algorithms is a crucial factor for successful practical implementation at the drinking water utility level. In this technical note, we therefore investigate the performance of a suite of genetic variators that was tailored to the optimisation of a least-cost network design. Different combinations of the variators are tested in terms of convergence rate and the robustness of the results during optimisation of the real world drinking water distribution network of Sittard, the Netherlands. The variator configurations that reproducibly reach the furthest convergence after 105 function evaluations are reported. In the future these may aid in dealing with the computational challenges of optimizing real world networks.


2018 ◽  
Vol 11 (2) ◽  
pp. 101-105
Author(s):  
Karel van Laarhoven ◽  
Ina Vertommen ◽  
Peter van Thienen

Abstract. Genetic algorithms can be a powerful tool for the automated design of optimal drinking water distribution networks. Fast convergence of such algorithms is a crucial factor for successful practical implementation at the drinking water utility level. In this technical note, we therefore investigate the performance of a suite of genetic variators that was tailored to the optimization of a least-cost network design. Different combinations of the variators are tested in terms of convergence rate and the robustness of the results during optimization of the real-world drinking water distribution network of Sittard, the Netherlands. The variator configurations that reproducibly reach the furthest convergence after 105 function evaluations are reported. In the future these may aid in dealing with the computational challenges of optimizing real-world networks.


2012 ◽  
Vol 5 (1) ◽  
pp. 515-532
Author(s):  
L. Mezule ◽  
S. Larsson ◽  
T. Juhna

Abstract. Sporadic detection of live (viable) Escherichia coli in drinking water with molecular methods but not with standard plate counts has raised concerns about the reliability of this indicator in the surveillance of drinking water safety. Previous studies have shown that in low numbers metabolically active E. coli can be found in the biofilm of drinking water. The aim of this study was to analyse the distribution of non-cultivable E. coli in the drinking water distribution system meeting microbiological quality standards and evaluate the importance of the biofilm as its harbour. In total 24 biofilm samplings and 40 at least 100 times pre-concentrated water samples were taken over a period of two years from two water treatment plants (surface water and groundwater) and four locations in water distribution network of a large city. Cultivable, total and able to divide (viable) E. coli concentration was measured in all samples. The results showed that none of the network biofilm samples contained cultivable E. coli and less than two cells per 10 l were detected in the pre-concentrated water samples. However, almost all of the samples contained viable E. coli in the range of 1–50 cells per litre or cm2 which represented approximately 53% of all E. coli detected. The amount of viable E. coli was higher in the biofilm after surface water treatment when compared to the outlet from the groundwater plant and the number tended to increase from both treatment plants further into the network irrespective of the season. In conclusion, E. coli in the water supply is not necessarily directly linked to recent faecal contamination and tends to accumulate in the networks where it is less exposed to disinfectants. Thus it can be accepted that biofilm formation in the drinking water distribution networks increases the risk of accumulation of viable but not cultivable E. coli in the system.


10.29007/b54r ◽  
2018 ◽  
Author(s):  
Peter van Thienen ◽  
Ina Vertommen ◽  
Karel van Laarhoven

Numerical tools for the optimization of several aspects of drinking water distribution networks have been around for some time now and are widely discussed in the scientific literature. However, their successful practical application remains a challenge, especially when combining multiple objectives and operational boundary conditions. In this contribution, we describe a number of optimization cases, including the optimization approaches applied. We discuss the technical and practical challenges that are faced when applying numerical optimization techniques to real world problems of water utilities.


2009 ◽  
Vol 9 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Elise Corbi ◽  
Valérie Jacquemet ◽  
Alain Quendo ◽  
Francine Manciot ◽  
Adeline Lamy ◽  
...  

Lyon, France has the opportunity to distribute in abundance a groundwater resource with a good quality for drinking water. However, the length and the complexity of the distribution network can lead to consumer complaints in some areas of the water distribution system. In order to improve the organoleptic quality of distributed water, the water supplier wants to get a better understanding of potential taste and odour formation and to succeed in controlling it. Since 2006, activities have been taken with targeted analyses and sensory evaluation of water, taking into account both the consumers' private networks and the citywide distribution network. The first results were focused on the occurrence of bromophenols along the water distribution system, the understanding of the mechanisms of formation of such compounds, as well as their incidence on taste-and-odour events at the consumer's home.


2019 ◽  
Vol 2 (1) ◽  
pp. 11 ◽  
Author(s):  
Arif Susanto ◽  
Purwanto Purwanto ◽  
Agus Hadiyarto

Abstract:. The requirement of consumed drinking water so that it does not create disturbance to public health is that it needs a quality monitoring. Water fluoridation in Tembagapura City aims to reach its concentration level toward certain safe level, and it can provide maximum benefits for dental health. Analysis and simulation methods using EPAnet software. The results of hydrolic simulation and water quality for fluoride concentration of each node and link in the drinking water distribution network system have changed in every time change following the drinking water distribution segment. From hydraulic simulations, especially for head and flow at separate points, it consists of simultaneous solution in flow equivalence for every junction and headloss relationship in every link of network as a result of hydraulic balancing. New segment will be made at the end of each link that receives inflow from a node if the quality of the new node is different from the link in the last segment. Every pipe in network contains singular segment where the water quality is in line with the preliminary quality stated in the preliminary node. With the availability of hydraulic model and water quality for fluoride concentration, a further research can be conducted for chlorine decay, growth of by product i.e. Trihalomethans (THMs) as well as water age simultaneously in drinking water supply systems in Tembagapura City.  Keyword: EPAnet, distribution network, fluoride concentration. Abstrak: Persyaratan kualitas air minum yang dikonsumsi masyarakat agar tidak menimbulkan gangguan kesehatan, maka penyelenggara air minum perlu melakukan pemantauan kualitasnya. Fluoridasi air di Kota Tembagapura ditujukan untuk mencapai tingkat konsentrasi fluoride pada level tertentu yang aman dan dapat memberikan manfaat maksimal bagi kesehatan gigi. Metode analisis dan simulasi menggunakan perangkat lunak EPAnet. Hasil simulasi hidrolis dan kualitas air untuk konsentrasi fluoride pada setiap node dan link pada sistem jaringan distribusi air minum berubah pada setiap perubahan waktu mengikuti segmen distribusi air minum tersebut. Dari simulasi hidrolis, khusus untuk head dan aliran pada titik yang terpisah meliputi penyelesaian secara simultan dalam persamaan aliran untuk tiap sambungan (junction), dan hubungan headloss pada setiap link pada jaringan sebagai akibat dari hydrolic balancing. Segmen baru terbentuk pada akhir dari setiap link yang menerima inflow dari sebuah node, jika kualitas node baru berbeda dari link pada segmen terakhir. Setiap pipa dalam jaringan mengandung segmen tunggal, di mana kualitas air sebanding dengan kualitas awal yang ditetapkan di node awal. Dengan tersedianya model hidrolis dan kualitas air untuk konsentrasi fluoride, maka dapat dilakukan penelitian lanjutan untuk peluruhan klorin, pertumbuhan by product yaitu trihalomethans (THMs) serta usia air secara simultan pada sistem penyediaan air minum di Kota Tembagapura.Kata Kunci: EPAnet, jaringan distribusi, konsentrasi fluoride.


Author(s):  
Alex Takeo Yasumura Lima Silva ◽  
Fernando Das Graças Braga da Silva ◽  
André Carlos da Silva ◽  
José Antonio Tosta dos Reis ◽  
Claudio Lindemberg de Freitas ◽  
...  

 Inefficiency of sanitation companies’ operation procedures threatens the population’s future supplies. Thus, it is essential to increase water and energy efficiency in order to meet future demand. Optimization techniques are important tools for the analysis of complex problems, as in distribution networks for supply. Currently, genetic algorithms are recognized by their application in literature. In this regard, an optimization model of water distribution network is proposed, using genetic algorithms. The difference in this research is a methodology based on in-depth analysis of results, using statistics and the design of experimental tools and software. The proposed technique was applied to a theoretical network developed for the study. Preliminary simulations were accomplished using EPANET, representing the main causes of water and energy inefficiency in Brazilian sanitation companies. Some parameters were changed in applying this model, such as reservoir level, pipe diameter, pumping pressures, and valve-closing percentage. These values were established by the design of experimental techniques. As output, we obtained the equation of response surface, optimized, which resulted in values of established hydraulic parameters. From these data, the obtained parameters in computational optimization algorithms were applied, resulting in losses of 26.61%, improvement of 16.19 p.p. with regard to the network without optimization, establishing an operational strategy involving three pumps and a pressure-reducing valve.  We conclude that the association of optimization and the planning of experimental techniques constitutes an encouraging method to deal with the complexity of water-distribution network optimization.


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