Exploring the social metabolism of urban wastewater reuse: Analysis framework and a case study in South-Central Chile

Although wastewater reuse is a vital strategy for mitigating water scarcity, its implementation is complex and faces several challenges. To effectively inform decision-makers, comprehensive evaluations are essential, considering the strategy's benefits and socio-ecological constraints in a case-specific manner. This study employs the social metabolism concept to assess the sustainability of wastewater reuse, through the joint application of the Material Flow Analysis (MFA) and Multiscale Integrated Assessment of Societal and Ecological Metabolism (MuSIASEM) tools. We analyze key aspects of wastewater reuse, including its potential as a water source, its technical challenges, and main social constraints. The results of our analysis highlight the potential of wastewater reuse to improve urban self-sufficiency, replace water in relevant economic activities at the regional level, and avoid the environmental impacts of wastewater discharge. Nevertheless, the viability of wastewater reuse is constrained by variations in wastewater flow and effluent quality. This limitation is further compounded by social barriers, which become more pronounced with increased contact with reclaimed water. Overall, the proposed framework serves as a valuable tool for evaluating wastewater reuse alternatives. It can be enriched by in-depth assessments of critical problems, providing a comprehensive approach to address the multifaceted aspects of sustainable wastewater reuse.