Supporting Environmental Decision-Making in Urban Water and Wastewater Systems: Proposal for an Environmental Performance Index

The operation of urban water and wastewater management systems (UWSs) generates environmental impacts that must be systematically identified and measured to develop appropriate management strategies. In addition, the capacity to satisfy the demand of the local population for water and wastewater services should be considered. This study proposes an environmental performance index that considers a comprehensive approach to evaluating the environmental impacts of UWS operations and incorporates indicators related to the demand for water and wastewater in the served region. The proposed index combines an Index of Potential Environmental Impacts (IPEI) based on Life Cycle Assessment (LCA) with an Index of the Deficit in the Provision of Services (IDES) to assess the Environmental Performance Index (EPI) of a UWS. The index was applied to a Brazilian UWS, and three operational scenarios were considered in the analysis. The results from the IPEI indicated that this indicator generally followed the same trend as the midpoint results obtained through LCA. However, when combined with the IDES results, Scenario 3 showed a 20% reduction in the EPI compared with the base scenario. Applying the EPI to a UWS allowed environmental performance to be evaluated through a unified indicator. Given the need to expand the Brazilian UWS infrastructure to meet the entire demand, the proposed index can be a valuable tool for selecting technologies and materials that exhibit better environmental performance.