Search results for "water distribution network"

A multi-objective and multi-criteria approach for district metered area design: water operation and quality analysis

2019

Water distribution network (WDN) operation may be improved by district metered area (DMA) design [1]. A first step to create DMAs uses graph theory and non-supervised learning, where physical features of the WDN, such as node coordinates, elevation and demand, are used for clustering purposes [2]. A second step is related to the necessary isolation of the clustered elements. For isolation purposes, it is important to determine the DMA entrances and, consequently, the needed cut-off valves. Closure of pipes and definition of DMA entrances can be set as an optimization problem with the costs associated to the valves, which are linked to pipe diameters, as a primary objective. However, placeme…

PUMP AS TURBINE (PAT) IN INTERMITTENT DISTRIBUTION NETWORKS

2012

A hydraulic model was performed in order to evaluate potential energy recovery resulting by the use of centrifugal pump as turbines (PAT) in the water distribution network characterized by the presence of private tanks. The model integrates the Enhanced Global Gradient Algorithm (EGGA) (Todini [1], Giustolisi et al. [2]), with a pressure driven model (Criminisi et al. [3]) that entails a more realistic representation of the influence of the private tanks filling and emptying process in the network behaviour. The model was applied to real case study: a district metered area in Palermo (Italy). Namely three different scenarios were analyzed and compared with the actual scenario (Scenario 0 - …

A model of the filling process of an intermittent distribution network

2010

In many countries, private tanks are acquired by users to reduce their vulnerability to intermittent supply. The presence of these local reservoirs modifies the user demand pattern and usually increases user water demand at the beginning of the service period depending on the tank filling process. This practice is thus responsible for the inequality that occurs among users: those located in advantaged positions of the network are able to obtain water resources soon after the service period begins, while disadvantaged users have to wait much longer, after the network is full. This dynamic process requires the development of ad hoc models in order to obtain reliable results. This paper discus…

Analysis of the Impact of the intermittent distribution by modelling the network filling processes.

2011

Water quality analysis in network and private storage tanks in intermittent distribution systems

2012

In countries suffering from chronic water shortages, water distribution systems are often operated on an intermittent basis. As a consequence, the network is involved by cyclical filling and emptying periods causing water quality degradation. During the emptying period, the distribution system is unpressurised and it may occur that pollutants move into the network. Moreover, the stagnation period can promote microbial growth. For this reason water is usually heavily chlorinated in order to maintain it potable. Due to intermittent water service users acquire private tanks, which are used for collecting water during serviced periods and distributing it when public service is not available. Th…

Energy Recovery in Water Distribution Networks. Implementation of Pumps as Turbine in a Dynamic Numerical Model

2014

In complex networks characterized by the presence of private tanks, water managers usually apply intermittent distribution, thus reducing the water volumes supplied to the users, or use Pressure Reduction Valves (PRV) for controlling pressure in the network. The application of Pump As Turbines (PATs) appears as an alternative and sustainable solution to either control network pressure as well as to produce energy. In the present paper, the hydrodynamic model, already presented by De Marchis et al. (2011) was further developed introducing the dynamic analysis of PATs. The model was applied to a district of Palermo network (Italy) characterized by intermittent distribution and by inequities a…

A numerical unsteady friction model for the transient flow arising during the filling process of intermittent water distribution systems.

2011

Evaluation of statistical sampling for the assessment of residential consumption totals in water distribution networks

2014

The paper provides insights into stratified sampling, a standard statistical technique that may be employed to assess domestic water use in water distribution networks. The basic idea is to use only a few meters to provide inference on the total water consumption of a network or of a district metered area through the knowledge of some additional stratification variables, such as household typology, size and occupants number. Since any sampling procedure assumes that the variance of the variable at stake is known, either a suitable amount of past consumption data is necessary, or a specific preliminary survey must be carried out, in order to define the sampling plan. An application with real…

Optimal positioning of water quality sensors in water distribution networks: Comparison of numerical and experimental results

2017

In the water distribution networks, a deliberate or accidental contamination causes loss of water quality; the implementation of a real-time sensor network is essential to promptly detect the event of contamination. To achieve the optimum positioning of the probes, to reduce the cost of the instrumentation and maintenance, and obtaining, at the same time, a reliable monitoring of the system, optimization techniques are widely applied. In the present study, a numerical optimisation approach was compared with the results of an experimental campaign. The optimization problem is formulated in accordance with literature stateof- the-art, using the genetic algorithm NSGA-II coupled with a hydraul…

Coupled Electric and Hydraulic Control of a PRS Turbine in a Real Transport Water Network

2019

Although many devices have recently been proposed for pressure regulation and energy harvesting in water distribution and transport networks, very few applications are still documented in the scientific literature. A new in-line Banki turbine with positive outflow pressure and a mobile regulating flap, named Power Recovery System (PRS), was installed and tested in a real water transport network for the regulation of pressure and flow rate. The PRS turbine was directly connected to a 55 kW asynchronous generator with variable rotational velocity, and coupled to an inverter. The start-up tests showed how automatic adjustment of the flap position and the runner velocity variation are able to c…