Strategic Assessment of Water Reuse Potential in Brazilian Watersheds Using Multi-Criteria Techniques

This study assesses the potential for water reuse from treated wastewater in the Rio dos Sinos and Rio Sapucaí watersheds in Brazil, applying the Analytic Hierarchy Process (AHP). The criteria evaluated include treatment efficiency, proximity to demand, supply capacity, and legal and institutional frameworks. An interactive dashboard was developed to support decision-making. Results show higher reuse potential in Rio dos Sinos for BOD removal >80%, meeting up to 46% of industrial or 17% of irrigation demand; the municipalities of Esteio, São Leopoldo, and Sapucaia do Sul are highlighted as high-potential areas. Rio Sapucaí shows better performance with 60-80% BOD removal, meeting 100% of industrial or 68% of irrigation demand, with Pouso Alegre identified as a high-potential municipality. Further development of the evaluation matrix and cost estimations are recommended.