An Environmental Analysis of the Effect of Energy Saving, Production and Recovery Measures on Water Supply Systems under Scarcity Conditions

Water is one of the primary resources provided for maintaining quality of life and social status in urban areas. As potable water is considered to be a primary need, water service has usually been managed without examining the economic and environmental sustainability of supply processes. Currently, due to increases in energy costs and the growth of environment preservation policies, reducing water leakage, energy consumption and greenhouse gas (GHG) production have become primary objectives in reducing the environmental footprint of water service. The present paper suggests the implementation of some performance indicators that show the interdependence of water loss, energy consumption and GHG emission. These indicators are used to compare a few possible mitigation scenarios involving water loss reduction and increasing the system's energy efficiency. The proposed indicators were applied to a complex urban water supply system serving the city of Palermo (Italy)

Floodability: A New Paradigm for Designing Urban Drainage and Achieving Sustainable Urban Growth

For a large part of human history, urbanization was focused on two main objectives: defence and resource harvesting. The first objective was always achieved in a broad sense, i.e., defending the population from other humans and from natural events. Focusing on human activities, this defensive approach was also applied to urban drainage, which resulted in a systematic underestimation of the impacts of urbanization on natural systems. Environmental sustainability was introduced in an attempt to mitigate these impacts, as they had the potential to endanger future developments; thus, the possibility that urban floods may be the lesser evil was accepted. Resilience was then introduced to improve not only defence of urban areas but also their ability to recover from negative events, even though physical resilience is not always accompanied by social resilience. This paper attempts to address the philosophy of urban drainage design, introducing the new concept of floodability as an evolution of flood resilience by identifying its requirements and drivers and by using real examples to present the new concept

Multicriteria performance analysis of an integrated urban wastewater system for energy management

The optimization and management of an integrated urban wastewater system is a complex problem involving many processes and variables. The possible control options are defined by several management strategies that may differently impact the economic, operational or environmental performance of the system. The present paper aims to contribute to the environmental and energy sustainability of urban wastewater systems by means of a multicriteria performance analysis. The paper begins with a complete analysis of the system performance in several fields of interest (energy, environment, quality of service, operation, economy and financial resources), and it highlights the management strengths and weaknesses in each subsystem. The analysis was carried out by means of a prototype, developed during the ALADIN project, which enables understanding the system, planning effective improvement actions and assessing their possible effects in each part of the urban water cycle. To demonstrate the potential of such an approach, it was tested on an actual integrated urban wastewater system in Sicily

Water and Energy Saving in Urban Water Systems: The ALADIN Project

The ALADIN project was aimed at contributing to environmental and energy sustainability of the urban water system by means of a decision support tool able to allow an evaluation of the energy impact related to each different macro-sectors of urban water cycle highlighting the main energy flows and to assess the system energy balance and identify the possible energy-efficient solutions. Moreover the tool suggests the most efficient actions in reducing water losses. In the present paper the main features of the developed tool are presented. (C) 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license

Contaminant Intrusion through Leaks in Water Distribution System: Experimental Analysis

This paper presents the results of experimental tests on the intrusion of contaminant through pipe cracks in water distribution network resulting from low/negative pressures. The tests were carried out on a looped distribution network at the University of Enna and were performed first producing a pressure transient that causes negative pressures then reproducing intermittent supply. A soluble contaminant was added to the water volume in the network through a pipe crack. Sampling of water volume was carried out in two nodes of the network and the contaminant concentrations were measured. It was showed that: the contaminant was drawn in and transported, in the first set of tests; the contaminant was carried through the network to the point-of-use when the pipes become completely full and the distribution system was in steady state conditions, in the second, and that the concentrations was higher than in the first set of test

Impact of diffusion and dispersion of contaminants in water distribution networks modelling and monitoring

Abstract In recent years, there has been a need to seek adequate preventive measures to deal with contamination in water distribution networks that may be related to the accidental contamination and the deliberate injection of toxic agents. Therefore, it is very important to create a sensor system that detects contamination events in real time, maintains the reliability and efficiency of measurements, and limits the cost of the instrumentation. To this aim, two problems have to be faced: practical difficulties connected to the experimental verification of the optimal sensor configuration efficiency on real operating systems and challenges related to the reliability of the network modelling approaches, which usually neglect the dispersion and diffusion phenomena. The present study applies a numerical optimization approach using the NSGA-II genetic algorithm that was coupled with a new diffusive-dispersive hydraulic simulator. The results are compared with those of an experimental campaign on a laboratory network (Enna, Italy) equipped with a real-time water quality monitoring system and those of a full-scale real distribution network (Zandvoort, Netherlands). The results showed the importance of diffusive processes when flow velocity in the network is low. Neglecting diffusion can negatively influence the water quality sensor positioning, leading to inefficient monitoring networks

A Decision Support System For Identifying Real Losses In Water Distribution Networks

The investigation of real losses is of paramount importance for water utility willing to control operational costs and environmental and social impacts of water supply. Real losses reduction could be achieved by continuous maintenance actions and occasional pipe substitutions. Maintenance activities in the distribution network represent one of the largest items in a water utility economic balance and, therefore, any approach aimed at maintenance optimization catches the interest of water managers. These strategies are constrained by the amount of funds, which are usually available not in a single instalment but yearly and spread over a time period of several years. Several models have been developed for determining network components’ optimal replacement time and rehabilitation planning by means of a Decision Support System - DSS. DSS actually provides highly valuable indications for infrastructure state and rehabilitation actions to undertake. DSS can also be used to address real losses investigation campaigns in order to focus monitoring efforts in those areas where real losses are probability higher. In the present paper, a procedure for leak detention in a water distribution network is proposed. The procedure is based on network flow and pressure monitoring, joined together with numerical dynamic modelling. The comparison between monitoring and modelling response is used to highlight the network pipes where real losses are most probably present. The decisional outputs are the selection of the pipes which have to be better investigated by means of active search methods. Considering the errors in monitoring data and the simplification in numerical modelling, the approach is coupled with uncertainty analysis in order to provide a probable leakage distribution with a specified level of reliability. The procedure is applied to a laboratory case study and the results obtained show that the proposed procedure has the potential to be a useful tool for rehabilitation scheduling

Pumps as turbines (PATs) in water distribution networks affected by intermittent service

A hydraulic model was developed in order to evaluate the potential energy recovery from the use of centrifugal pumps as turbines (PATs) in a water distribution network characterized by the presence of private tanks. The model integrates the Global Gradient Algorithm (GGA), with a pressure-driven model that permits a more realistic representation of the influence on the network behaviour of the private tanks filling and emptying. The model was applied to a real case study: a District Metered Area in Palermo (Italy). Three different scenarios were analysed and compared with a baseline scenario (Scenario 0 - no PAT installed) to identify the system configuration with added PATs that permits the maximal energy recovery without penalizing the hydraulic network performance. In scenarios involving PAT on service connections, the specification of PAT operational parameters was also evaluated by means of Monte Carlo Analysis. The centralized solution with a PAT installed downstream of the inlet node of the analysed district, combined with local PATs on the larger service connections, proves to be the most energy-efficient scenario