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- Optimal location and setting of time modulated PRVs for water loss reduction with leakage modelling by pressure driven analysisPublication . Sousa, J.; Muranho, João; Sá Marques, Alfeu; Gomes, RicardoWater losses have economical, technical, social and environmental negative impacts and so water companies are always willing to reduce them. The IWA Water Loss Task Force identified four main control strategies to reduce real losses: 1) infrastructure management; 2) pressure management; 3) active leakage control; and 4) speed and quality of repairs. Unreported leaks and background leakage usually represent a major component of water losses and pressure management is an effective, easy, economic and quick solution to reduce it. Pressure management can be implemented by introducing Pressure Reduction Valves (PRVs): fixed-outlet; time-modulated; flow-modulated and pressure modulated. For a fixed-outlet PRV there is a single working condition (pressure downstream of the PRV is always the same). For a time-modulated PRV there can be several working conditions (for instance, a lower pressure during the night period - from 0 to 6 am, and higher one during the remainder of the day). The flow-modulated and pressure modulated PRVs are more efficient because they constantly try to adjust the working conditions to reach the minimum pressure required at the critical node. However, pressure management projects must be preceded by specialized studies (identify the optimal location and settings of the PRVs to install) and cost benefit analysis (assessment of economic viability). A previous work presented a methodology to help in those tasks, by identifying the optimal location and setting of fixed-outlet PRVs to reduce water losses in WDNs and maximize the NPV of pressure management projects. Now the methodology was extended to include also time modulated PRVs and this paper presents the results obtained for a hypothetical case study.
- Optimal District Metered Area Design by Simulated AnnealingPublication . Gomes, Ricardo; Sousa, J.; Marques, Alfeu Sá; Muranho, JoãoWater losses reduction in Water Distribution Systems (WDSs) is nowadays an issue of growing importance for water companies to ensure the economic sustainability of these public services. In this context, the implementation of District Metered Areas (DMAs) and/or pressure management are considered effective tools for leakage control, particularly in large networks and in systems with deteriorated infrastructures and with high pressure. Based in previous studies performed by the authors (Gomes et al., 2012; Gomes et al., 2015; Sousa et al., 2015), the methodology described in this paper follows the ‘water losses management international best practices’ and makes it possible to evaluate the Net Present Value (NPV) of DMAs project, as well as the benefits that can be achieved by pressure management in WDS, particularly in terms of water production reduction. Leakage assessment is performed using the analysis of the minimum night flow and the FAVAD concept, and it uses a pressure driven simulation model to predict the network hydraulic behaviour under different pressure conditions. The optimal location of DMAs entry points, pipes reinforcement/replacement and locations/settings of the Pressure Reduction Valves (PRVs) are identified by a Simulated Annealing algorithm. The potential of this methodology is illustrated through an hypothetical case study.
- Optimal District Metered Area design by Simulated AnnealingPublication . Gomes, Ricardo; Sousa, J.; Sá Marques, Alfeu; Muranho, JoãoWater losses reduction in Water Distribution Systems (WDS) is nowadays an issue of growing importance for water companies to ensure the sustainability of these public services. In this context, the implementation of District Metered Areas (DMAs) and/or pressure management are considered the most effective tools for leakage control, particularly in large networks and in systems with deteriorated infrastructures and with high pressure. Based in previous studies performed by the authors [1,2,3], the methodology described in this paper follows the ‘water losses management international best practices’ and makes it possible to evaluate the Net Present Value (NPV) of DMAs project, as well as the benefits that can be achieved by pressure management in WDS, particularly in terms of water production reduction. It is based on the analysis of the minimum night flow and the FAVAD concept, and it uses a pressure driven simulation model to predict the network hydraulic behaviour under different pressure conditions. Leakage assessment is performed using pressure driven analysis and the optimal location of pipes reinforcement/replacement and settings of the Pressure Reduction Valves (PRVs) are identified by a Simulated Annealing algorithm. The potential of this methodology is illustrated through an hypothetical case study.