scholarly journals A Simplified Methodology for Optimal Location and Setting of Valves to Improve Equity in Intermittent Water Distribution Systems

2021 ◽  
Author(s):  
Aurora Gullotta ◽  
Alberto Campisano ◽  
Enrico Creaco ◽  
Carlo Modica
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Computational Effort ◽  
Nsga Ii ◽  
Optimal Position ◽  
Flow Circulation ◽  
Optimization Schemes ◽  
The Impact ◽  
Supply Level

AbstractIn this paper, a simplified methodology to increase the water distribution equity in existing intermittent water distribution systems (WDSs) is presented. The methodology assumes to install valves in the water distribution network with the objective to re-arrange the flow circulation, thus allowing an improved water distribution among the network users. Valve installation in the WDS is based on the use of algorithms of sequential addition (SA). Two optimization schemes based on SA were developed and tested. The first one allows identifying locations of gate valves in order to maximize the global distribution equity of the network, irrespectively of the local impact of the valves on the supply level of the single nodes. Conversely, the second scheme aims to maximize the global equity of the network by optimizing both location and setting (opening degree) of control valves, to include the impact of the new flow circulation on the supply level of each node. The two optimization schemes were applied to a case study network subject to water shortage conditions. The software EPA Storm Water Management Model (SWMM) was used for the simulations in the wake of previous successful applications for the analysis of intermittent water distribution systems. Results of the application of the SA algorithms were also compared with those from the literature and obtained by the use of the multi-objective Non-Dominated Sorted Genetic Algorithm II (NSGA II). The results show the high performance of SA algorithms in identifying optimal position and settings of the valves in the WDS. The comparison pointed out that SA algorithms are able to perform similarly to NSGA II and, at the same time, to reduce significantly the computational effort associated to the optimization process.

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.

Robust booster chlorination in water distribution systems: design and operational perspectives under uncertainty

2019 ◽  
Vol 68 (6) ◽  
pp. 399-410
Author(s):  
Denis Nono ◽  
Innocent Basupi
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Systems Design ◽  
Nsga Ii ◽  
Chlorine Disinfection ◽  
Uncertain Network ◽  
Network Operations ◽  
Booster Chlorination ◽  
Injection Rates

Abstract Booster chlorination designs have been widely based on predefined (deterministic) network conditions and they perform poorly under uncertainty in water distribution systems (WDSs). This paper presents a scenario-based robust optimisation approach which was developed to obtain booster chlorination designs that withstand uncertain network operations and water demand conditions in the WDSs. An optimisation problem was formulated to minimise mass injection rates and the risk of chlorine disinfection. This problem was solved by a non-dominated sorting genetic algorithm (NSGA-II). The proposed approach was demonstrated using the Phakalane network in Botswana. The results present robust booster chlorination (RBC) designs, which indicate the number of boosters, locations and injection rates in the network. The performance of RBC designs evaluated under uncertainty reveals lower risks of chlorine disinfection compared to deterministic-based designs. The proposed approach obtains booster chlorination designs that respond better to uncertainty in the operations of WDSs.

Stochastic approach for performance evaluation regarding water distribution systems

2007 ◽  
Vol 56 (9) ◽  
pp. 29-36 ◽  
Author(s):  
M. Möderl ◽  
T. Fetz ◽  
W. Rauch
Keyword(s):  
Performance Evaluation ◽  
Case Studies ◽  
Distribution Systems ◽  
Water Distribution ◽  
Performance Indicator ◽  
Water Distribution Systems ◽  
Stochastic Approach ◽  
Cumulative Distribution ◽  
Design System ◽  
The Impact

A traditional procedure for performance evaluation of systems is to test approaches on one or more case studies. However, it is well known that the investigation of real case studies is a tedious task. Moreover, due to the limited amount of case studies available it is not certain that all aspects of a problem can be covered in such procedure. With increasing computer power an alternative methodology has emerged, that is the investigation of a multitude of virtual case studies by means of a stochastic consideration of the overall performance. Within the frame of this approach we develop here a modular design system (MDS) for water distribution systems (WDSs). With the algorithmic application of such a MDS it is possible to create a variety of different WDSs. As an example of stochastic performance evaluation the impact of pipe breakages on WDSs is estimated applying a pressure driven performance indicator. This performance indicator is evaluated stochastically. Likewise the performance evaluation of a variety of WDSs is also performed stochastically. Cumulative distribution function, histogram and other statistical properties of 2,280×1,000 performance results of the different WDSs are calculated to highlight the applicability of the introduced stochastic approach.

scholarly journals Multiobjective contaminant response modeling for water distribution systems security

2008 ◽  
Vol 10 (4) ◽  
pp. 267-274 ◽  
Author(s):  
Ami Preis ◽  
Avi Ostfeld
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Public Awareness ◽  
Water Distribution Systems ◽  
Evolutionary Model ◽  
Water Supply Systems ◽  
Nsga Ii ◽  
Drinking Water Distribution Systems ◽  
Conflicting Objectives ◽  
Operational Activities

Following the events of 9/11/2001 in the US, the world public awareness to possible terrorist attacks on water supply systems has increased significantly. The security of drinking water distribution systems has become a foremost concern around the globe. Water distribution systems are spatially diverse and thus are inherently vulnerable to intentional contamination intrusions. In this study, a multiobjective optimization evolutionary model for enhancing the response against deliberate contamination intrusions into water distribution systems is developed and demonstrated. Two conflicting objectives are explored: (1) minimization of the contaminant mass consumed following detection, versus (2) minimization of the number of operational activities required to contain and flush the contaminant out of the system (i.e. number of valves closure and hydrants opening). Such a model is aimed at directing quantitative response actions in opposition to the conservative approach of entire shutdown of the system until flushing and cleaning is completed. The developed model employs the multiobjective Non-Dominated Sorted Genetic Algorithm–II (NSGA-II) scheme, and is demonstrated using two example applications.

Regulation response of pilot operated diaphragm pressure reducing valves: laboratory testing and impact on the performance of pressure control modes in water distribution systems

2021 ◽  
Author(s):  
Mouna Doghri ◽  
Sophie Duchesne ◽  
Annie Poulin ◽  
J.-P. Villeneuve
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Pressure Control ◽  
Quebec City ◽  
Real Time Control ◽  
Hydraulic Simulation ◽  
Pressure Setting ◽  
Time Control ◽  
The Impact

Pressure control is recognized as an efficient measure to reduce leaks from water distribution systems. The effectiveness of various pressure control modes, by means of pilot operated diaphragm pressure reducing valves (PRVs), is evaluated in this paper taking into account the sensitivity of the valve to various settings. First, the response of a PRV to consecutive pressure settings variations was experimentally evaluated in the hydraulic simulation laboratory of National Institute for Scientific Research (INRS). These experiments revealed that the studied valve reacts only when the pressure setting variation corresponds to at least 1/6 turn of the pilot valve. Second, a real case study from Quebec City, Canada, was simulated in order to evaluate the impact of the PRV response on three pressure control modes: fixed control, time based control, and real time control (RTC). The results show that RTC of pressure leads to leakage rate reduction on the studied network but that the PRV operational constraints limit the expected performance of RTC.

scholarly journals Risk-based sensor placement methods for burst/leak detection in water distribution systems

2017 ◽  
Vol 17 (6) ◽  
pp. 1663-1672 ◽  
Author(s):  
E. Forconi ◽  
Z. Kapelan ◽  
M. Ferrante ◽  
H. Mahmoud ◽  
C. Capponi
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Social Economic ◽  
Water Distribution Systems ◽  
Water System ◽  
Water Distribution Network ◽  
Leak Detection ◽  
Optimal Placement ◽  
Water Volume ◽  
The Impact

Abstract The optimal placement of sensors for burst/leak detection in water distribution systems is usually formulated as an optimisation problem. In this study three different risk-based functions are used to drive optimal location of a given number of sensors in a water distribution network. A simple function based on likelihood of leak non-detection is compared with two other risk-based functions, where impact and exposure are combined with the leak detection likelihood. The impact is considered proportional to the demand water volume while the exposure is related to the importance of the connections and it is evaluated in social, economic or safety terms. The methods are applied to a district metered area of the Harrogate network by means of a modified EPANET model, to take into account the pressure-driven functioning conditions of the system. The results show that the exposure can lead to a different sensor location ranking with respect to other criteria used and hence the proposed methodology can represent a useful tool for water system managers to distribute the sensors in the network, complying with hydraulic, social and economical requirements.

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