scholarly journals The influence of the existing network layout on water distribution system redesign analysis

2014 ◽  
Vol 16 (6) ◽  
pp. 1375-1389 ◽  
Author(s):  
C. Tricarico ◽  
M. S. Morley ◽  
R. Gargano ◽  
Z. Kapelan ◽  
G. de Marinis ◽  
...  
Keyword(s):  
System Reliability ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Optimal Solution ◽  
Optimal Solutions ◽  
Network Configuration ◽  
Decision Variables ◽  
The Impact ◽  
Optimisation Technique

The methodologies usually adopted in water distribution system redesign problems consider the topology of the network as an input fixed datum; optimisation solely allowing for the duplication/substitution of existing components. In order to contribute to the identification of optimal solutions that may lead to a lower risk of failure to supply the required water, together with a lower redesign cost, this paper proposes a novel methodology which reports the influence of the existing network configuration and its performance. In particular, the redundancy of loops and the robustness of the network topology are investigated by applying an optimisation technique based on a genetic algorithm and by taking into account the random water demand at each node. The methodology presented has been applied to two case studies, in which it considers the influence of the topology on the overall system reliability/risk. The results demonstrate that it is possible to obtain further configurations that are more reliable for a lower redesign cost. The analysis performed highlights the impact of the topology on the search for an optimal solution, which, as a principal conclusion of the work, should be considered among the decision variables taken into account by the optimisation in a redesign problem.

scholarly journals How close simple EAs’ optimal solutions can approach global optima: experience from water distribution system design problems

2020 ◽  
Author(s):  
Hang Yin ◽  
Chengna Xu ◽  
Fengyi Yao ◽  
Shipeng Chu ◽  
Yuan Huang
Keyword(s):  
Genetic Algorithm ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Optimal Solutions ◽  
Design Problems ◽  
Decision Variables ◽  
Global Optima ◽  
Global Optimal

Abstract An issue regarding near-optimal solutions identified by evolutionary algorithms (EAs) is that their absolute deviations from the global optima are often unknown, and hence an EA's performance in handling real-world problems remains unclear. To this end, this paper investigates how close optimal solutions from simple EAs can approach the global optimal for water distribution system (WDS) design problems through an experiment with the number of decision variables ranging from 21 to 3,400. Three simple EAs are considered: the standard differential evolution, the standard genetic algorithm and the creeping genetic algorithm (CGA). The CGA consistently identifies optimal solutions with deviations lower than 50% to the global optimal, even for the WDS with 3,400 decision variables, but the performance of the other two EAs is heavily case study dependent. Results obtained build knowledge regarding these simple EAs’ ability in handling WDS design problems with different sizes. We must acknowledge that these results are conditioned on the WDSs and the parameterization strategies used, and future studies should focus on generalizing the findings obtained in this paper.

Variations of DBPs precursors according to location within the distribution system

2009 ◽  
Vol 9 (4) ◽  
pp. 413-421
Author(s):  
C. Beaulieu ◽  
M. J. Rodriguez ◽  
J.-B. Sérodes
Keyword(s):  
Organic Matter ◽  
Water Treatment ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Spatial Behavior ◽  
Haloacetic Acids ◽  
Formation Potential ◽  
The Impact ◽  
By Products

Little information is available on the evolution of remaining organic matter (ROM) in a water distribution system (WDS) and its impact on the generation of disinfection by-products (DBPs). This research involves the characterization, through sample fractionation processes and experimental chlorination tests, of the reactivity of DBP precursors occurring within a WDS. The study is based on samples collected in various locations of a WDS during a complete year. For each sample, six fractions were generated to determine their potential for formation of trihalomethanes (THMs) and haloacetic acids (HAAs). Fractionation processes on ROM demonstrated that the spatial behavior of precursors for THMs differs from that for precursors of HAAs. In addition, experimental chlorination tests showed that the reactivity of the investigated fractions, in terms of DBP formation potential (DBPfp), was different from each other according to location in the WDS. DBPfp for the studied fractions changed drastically during water treatment. However, changes of DBPfp for fractions were relatively low between the beginning and the extremity of the distribution system. Since the results of this research confirm that the ability to produce DBPs is related to the nature of the fractions, they could be useful to evaluate the impact of re-chlorination on DBP formation in a WDS.

Investigation of the Impact of Anti-Negative Pressure Facility on a Water Distribution System

2013 ◽  
Vol 316-317 ◽  
pp. 719-722
Author(s):  
Huan Huan Wang ◽  
Shu Ming Liu ◽  
Fan Lin Meng ◽  
Lu Bai
Keyword(s):  
Water Supply ◽  
Negative Pressure ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Simulation Method ◽  
Water Tank ◽  
Research Activities ◽  
High Level ◽  
The Impact

High level water tank is a commonly used facility to satisfy water demand for people living in high building, which is also the so-called secondary water supply system (SWSS) in China. Due to lack of maintenance, water quality problem has been frequently reported in the SWSS. In the last few decades, anti-negative pressure facility (ANPF) has emerged as a revolutionary approach for solving the pollution in the SWSS. ANPF makes good use of the municipal pipeline pressure, which is the improvement of traditional water supply. However, most of recent research activities mainly focus on the influence of part of water distribution system (WDS). In this paper, the software of EPANET has been applied in the SWSS calculation and simulation. Besides that, the SWSS with ANPF simulation method is proposed to evaluate the effect of other all nodes pressure in the WDS using hydraulic model. As the cases study, the paper analyzed two WDSs with ANPF. After simulation of the SWSS, the result of WDS, which is smaller, indicates that 6 out of the 9 nodes are affected with ANPF and that of WDS, which is larger, demonstrates that 37 out of the 41 nodes are affected and the affected nodes are focused on the confluent of pipes, especially around the ANPF.

Molecular characterization of bacteria inhabiting a water distribution system simulator

2003 ◽  
Vol 47 (5) ◽  
pp. 149-154 ◽  
Author(s):  
J.W. Santo Domingo ◽  
M.C. Meckes ◽  
J.M. Simpson ◽  
B. Sloss ◽  
D.J. Reasoner
Keyword(s):  
16S Rdna ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Heterotrophic Bacteria ◽  
Feed Water ◽  
Ammonia Oxidizing Bacteria ◽  
16S Rdna Pcr ◽  
The Impact

The objective of this study was to monitor the impact of chlorination and chloramination treatments on heterotrophic bacteria (HB) and ammonia-oxidizing bacteria (AOB) inhabiting a water distribution system simulator. HB densities decreased while AOB densities increased when chloramine was added. AOB densities decreased below detection limits after the disinfection treatment was switched back to chlorination. The presence of AOB was confirmed using a group-specific 16S rDNA-PCR method. 16S rDNA sequence analysis showed that most bacterial isolates from feed water, discharge water, and biofilm samples were α-Proteobacteria or β-Proteobacteria. The latter bacterial groups were also numerically dominant among the sequences recovered from water and biofilm 16S rDNA clone libraries. The relative frequency of each culturable bacterial group was different for each sample examined. Denaturing gradient gel electrophoresis analysis of total community 16S rDNA genes showed notable differences between the microbial community structure of biofilm samples and feed water. The results of this study suggest that disinfection treatments could influence the type of bacterial community inhabiting water distribution systems.

Biofilms in an urban water distribution system: measurement of biofilm biomass, pathogens and pathogen persistence within the Greater Stockholm area, Sweden

2005 ◽  
Vol 52 (8) ◽  
pp. 181-189 ◽  
Author(s):  
J. Långmark ◽  
M.V. Storey ◽  
N.J. Ashbolt ◽  
T.A. Stenström
Keyword(s):  
Distribution System ◽  
Pilot Plant ◽  
Water Distribution ◽  
Water Distribution System ◽  
Microbial Pathogens ◽  
Urban Water ◽  
Uv Treatment ◽  
Aesthetic Quality ◽  
Wide Range ◽  
The Impact

Distribution pipe biofilms can provide sites for the concentration of a wide range of microbial pathogens, thereby acting as a potential source of continual microbial exposure and furthermore can affect the aesthetic quality of water. In a joint project between Stockholm Water, the MISTRA “Sustainable Urban Water” program, the Swedish Institute for Infectious Disease Control and the Royal Technical University, Stockholm, the aim of the current study was to investigate biofilms formed in an urban water distribution system, and quantify the impact of such biofilms on potential pathogen accumulation and persistence within the Greater Stockholm Area, Sweden. When used for primary disinfection, ultra-violet (UV) treatment had no measurable influence on biofilm formation within the distribution system when compared to conventional chlorination. Biofilms produced within a model pilot-plant were found to be representative to those that had formed within the larger municipal water distribution system, demonstrating the applicability of the novel pilot-plant for future studies. Polystyrene microspheres (1.0μm) and Salmonella bacteriophages demonstrated their ability to accumulate and persist within the model pilot-plant system, where the means of primary disinfection (UV-treatment, chlorination) had no influence on such phenomena. With the exception of aeromonads, potential pathogens and faecal indicators could not be detected within biofilms from the Stockholm water distribution system. Results from this investigation may provide information for water treatment and distribution management strategies, and fill key data gaps that presently hinder the refinement of microbial risk models.

scholarly journals Near-optimal scheduling of device activation in water distribution systems to reduce the impact of a contamination event

2011 ◽  
Vol 14 (2) ◽  
pp. 345-365 ◽  
Author(s):  
S. Alvisi ◽  
M. Franchini ◽  
M. Gavanelli ◽  
M. Nonato
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Optimal Scheduling ◽  
Mixed Integer ◽  
Maximum Speed ◽  
Contaminated Water ◽  
Flow Control Devices ◽  
The Impact

This paper proposes an innovative procedure for identifying, in the event of accidental or intentional contamination of a water distribution system, the optimal scheduling of activation of a pre-selected set of flow control devices which will serve to minimise the volume of contaminated water consumed by users after the detection of the contaminant in the system. The constraints are represented by the number of available response teams and the maximum speed at which these teams can travel along the roadway. The optimal scheduling of device activation is sought by means of an optimisation process based on a genetic algorithm (GA) which interacts with a mixed integer linear programming (MILP) solver in order to ensure the feasibility of the scheduling identified. The optimisation procedure is coupled to a hydraulic and quality simulator, which enables a calculation of the volumes of contaminated water consumed by users, and a dynamic cache memory, which, by storing information on the system's behaviour as the optimisation process progresses, serves to limit the computational times. The application of the procedure to a highly complex real water distribution system shows that the optimisation process is robust and efficacious and produces a smaller volume of contaminated water consumed by the users than when the activation of all the devices was completed in the shortest amount of time.

Implementasi Ant Colony Optimization (ACO) pada Sistem Irigasi Lahan Tadah Hujan

Kilat ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 336-348
Author(s):  
Abdul Haris ◽  
Trisma Juwita ◽  
Rosida Nur Aziza ◽  
Hengki Sikumbang ◽  
Riki Ruli A. Siregar
Keyword(s):  
Ant Colony Optimization ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Irrigation System ◽  
Ant Colony ◽  
Irrigation Systems ◽  
Distribution Process ◽  
Soil Dryness ◽  
The Impact

The purpose of this research is to produce an optimal water distribution system for irrigation of rainfed land. The problem with conventional irrigation systems is that the water distribution process cannot be controlled and monitored automatically and in real time. The impact on water distribution becomes ineffective. The implementation of Ant Colony Optimization (ACO) is used in research as a method to determine the location or node based on the pheromone pattern of the soil dryness level at the sprinkler nodes to be distributed by the water flow, taking into account the criteria level on the soil as a trend of probability values ​​and determining the nodes according to the needs in the flow water. The results obtained from this study indicate that the data displayed is the level of dryness of each node, the volume of water in the reservoir, and the flow of water flowing. The ACO test shows the sequence of nodes that will be passed after the optimization process of water distribution in a rainfed irrigation system using the ACO method gets an error value calculated by the MAPE method of 43% so that it gets an accuracy value of 57%.

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