Search results for "water distribution system"

Consistent Clustering of Elements in Large Pairwise Comparison Matrices

2018

[EN] In multi-attribute decision making the number of decision elements under consideration may be huge, especially for complex, real-world problems. Typically these elements are clustered and then the clusters organized hierarchically to reduce the number of elements to be simultaneously handled. These decomposition methodologies are intended to bring the problem within the cognitive ability of decision makers. However, such methodologies have disadvantages, and it may happen that such a priori clustering is not clear, and/or the problem has previously been addressed without any grouping action. This is the situation for the case study we address, in which a panel of experts gives opinions…

Multi-criteria analysis applied to multi-objective optimal pump scheduling in water systems

2019

Abstract This work presents a multi-criteria-based approach to automatically select specific non-dominated solutions from a Pareto front previously obtained using multi-objective optimization to find optimal solutions for pump control in a water supply system. Optimal operation of pumps in these utilities is paramount to enable water companies to achieve energy efficiency in their systems. The Fuzzy Technique for Order of Preference by Similarity to Ideal Solution (FTOPSIS) is used to rank the Pareto solutions found by the non-dominated sorting genetic algorithm (NSGA-II) employed to solve the multi-objective problem. Various scenarios are evaluated under leakage uncertainty conditions, res…

Some awkward issues on pairwise comparison matrices

2017

Many decision-making techniques use pairwise comparisons (PCs) elicited by one or more stakeholders involved in a given corresponding decision-making process. In very complex problems, the number of criteria or options to be compared may be too large, thus limiting PC applicability to large-scale decision problems due to the so-called curse of dimensionality, that is, a large number of pairwise comparisons need to be produced from a decision maker. For example, in AHP, Saaty [1] recommends that to obtain a reasonable and consistent PC matrix, the number of comparing elements should be at most seven. In [2] and [3], arguing on limitations of the human capabilities, the maximum number of elem…

Genotyping of Legionella pneumophila serogroup 1 strains isolated in Northern Sicily, Italy.

2008

During a three-year period, from April 2002 to May 2005, one hundred-forty-seven samples, taken from technical systems of water distribution at point of use, were repeatedly collected at six different sites in Northern Sicily and assayed for the presence of Legionella pneumophila serogroup 1 and serogroups 2 to 14. At the first samplings, the water distribution systems of all the sites were heavily contaminated, and disinfection treatments by the superheat and flush method were therefore performed. Treatments were always successful against L. pneumophila sg.1, but only in a few cases against all other serogroups. Eighty-six strains of L. pneumophila sg. 1, isolated from 26 of these samples,…

A BASIC DECISION SUPPORT SYSTEM FOR IMPROVING SERVICE LEVEL IN INTERMITTENT WATER DISTRIBUTION SYSTEMS

2012

Prioritization of maintenance actions in water distribution systems

2017

[EN] Industrial water distribution systems are paramount in many manufacturing systems to optimise the related industrial plant availability and consequently the level of production. They also play an important part in keeping right standards of hygiene of workplaces and machines. A strategic action of planning and implementing of suitable maintenance activities is necessary to assure the standards previously described. The present contribution proposes the prioritization of maintenance actions for industrial water distribution systems through a multi-criteria decision making approach, since some of the elements integrated in maintenance-related aspects are not easily quantifiable and, on t…

District metered area design through multicriteria and multiobjective optimization

2022

[EN] The design of district metered areas (DMA) in potable water supply systems is of paramount importance for water utilities to properly manage their systems. Concomitant to their main objective, namely, to deliver quality water to consumers, the benefits include leakage reduction and prompt reaction in cases of natural or malicious contamination events. Given the structure of a water distribution network (WDN), graph theory is the basis for DMA design, and clustering algorithms can be applied to perform the partitioning. However, such sectorization entails a number of network modifications (installing cut-off valves and metering and control devices) involving costs and operation changes,…

Stochastic Approach for Optimal Positioning of Pumps As Turbines (PATs)

2021

A generic water system consists of a series of works that allow the collection, conveyance, storage and finally the distribution of water in quantities and qualities such as to satisfy the needs of end users. In places characterized by high altitude differences between the intake works and inhabited centres, the potential energy of the water is very high. This energy is attributable to high pressures, which could compromise the functionality of the pipelines

Multi-Objective and Multi-Criteria Analysis for Optimal Pump Scheduling in Water Systems

2018

This contribution focuses on the problem of optimal pump scheduling, a fundamental element in pursuing operation optimization of water distribution systems. A combined approach of multi-objective optimization and multi-criteria analysis is herein suggested to first find the Pareto front of non-dominated solutions and then to rank them based on a set of weighted criteria. The Non-Dominated Sorting Genetic Algorithm (NSGA-II) is proposed to solve the multi-objective problem, while the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is used to achieve the final ranking.

Water quality sensor placement: a multi-objective and multi-criteria approach

2021

[EN] To satisfy their main goal, namely providing quality water to consumers, water distribution networks (WDNs) need to be suitably monitored. Only well designed and reliable monitoring data enables WDN managers to make sound decisions on their systems. In this belief, water utilities worldwide have invested in monitoring and data acquisition systems. However, good monitoring needs optimal sensor placement and presents a multi-objective problem where cost and quality are conflicting objectives (among others). In this paper, we address the solution to this multi-objective problem by integrating quality simulations using EPANET-MSX, with two optimization techniques. First, multi-objective op…