Priorização de investimentos para redução de perdas em sistemas de abastecimento de água e indicador de custo por sistema: uma avaliação com análise multicritério - AHP

Abstract

The issue of water loss in supply systems involves various influential variables, presenting a multifaceted challenge with significant impacts on supply, such as financial waste from unbilled produced water and increased operational demands on the system. This complexity makes multi-criteria analysis promising for decision-making processes. This study applied the Analytic Hierarchy Process (AHP) methodology to prioritize investments aimed at reducing water losses in water supply systems operated by the Water and Sewage Company of Paraíba (CAGEPA), focusing on isolated systems with similar size and loss levels, thereby avoiding a bias towards municipalities with the highest percentage loss rates. Two municipalities, Catolé do Rocha and Mamanguape, were selected based on operational indicators, such as distribution loss rate and distributed volume. In this multi-criteria methodology, the assessed criteria included operational indicators such as the number of active connections, percentage loss, loss per connection, distributed volume, and the number of leaks in networks or branches. The leak indicator was calculated based on data obtained from CAGEPA. Data normalization enabled direct comparisons between the municipalities, resulting in a priority ranking where Mamanguape received the highest score, indicating a higher investment priority in loss reduction as assessed by CAGEPA experts. It was found that for the evaluation group, the most critical criteria were Loss per Connection Index, with a global weight of 54.80%, and the Number of Leaks in Networks and Branches with 25.80%. Finally, the unit operating cost was recognized as a crucial criterion for evaluating system performance; it was therefore calculated and found to be R$ 1.86/m³ for Catolé do Rocha and R$ 1.20/m³ for Mamanguape. This cost indicator can be applied in other studies as an AHP criterion and highlights the importance of loss control, with potential for replication across systems in future multi-criteria analyses related to water distribution loss management.