Estudo da minimização das perdas físicas em sistema de distribuição de água utilizando o modelo Epanet

Abstract

The control and the reduction of water losses in the world is a fundamental instrument for cultural change, which is necessary as a basic natural resource to life. The objective of this research is to study the minimization possibilities of physical losses (leakage) in the sector of water distribution system located in Nossa Senhora de Lourdes district and its immediacy in Santa Maria - RS. This sector is closed hydraulically, monitored by a volume macromeasurer and operated with 3 pitot tube stations installed to measure flow and pressure in inlet subsectors 1, 2 and 3. In the hydraulic behavior modeling of the sector in study, it was used EPANET model, free software developed by the U. S. Environmental Protection Agency. From this calibrated model with mean absolute error of 0.159 L/s for flows and 1.984 m for pressure, it was possible to create a comparison term and to simulate interventions as: adjustment in the existing PRV, links substitution, network setorization and installation of new PRV. The installation of 2 new PRV in inlet subsectors 1 and 2 operating with the minimum openings was the intervention that presented the best reduction of the average leakage flow (2.14 L/s). Networks had been simulated in EPANET model with different pairs of parameters of pressure versus leakage relation, in order to verify the variation in pressures and consequently in leakage due to the setting in the PRV. The correct operation of a PRV allied to the distribution of the only necessary water volume to each sector not only reduces waste, but could also to solve supply deficiencies in other sectors. Water loss reduction decreases costs of Sanitation Company and population. It also reduces the amount of water removed from natural sources and contributes to environment preservation.