Environmental assessment of an urban water system

The environmental impacts derived from the urban water system of the municipality of Aveiro (Portugal) were analysed in this study using the Life Cycle Assessment (LCA) methodology. In addition, those stages and processes with the largest environmental impacts were identified and improvement scenarios were proposed. The entire water system was considered, including the following stages: water abstraction and treatment, water distribution, sewage collection, wastewater treatment and disposal, and water administration.The results show that the stage of water abstraction and treatment was the most relevant for the majority of impact categories because most of the electricity consumption happened during this stage. For marine eutrophication and marine ecotoxicity, the stage of wastewater treatment and disposal alone carried almost the entire burden because of the release of nitrogen and phosphorus into the sea.Electricity consumption and discharge of nutrients to the sea have been identified as the largest contributors to the environmental impacts. Therefore, scenarios focused on changing these burdens were assessed in order to prioritise those actions that would bring the greatest improvements. The proposed improvement actions could be a basis for the decision-making process regarding future investments towards environmental sustainability of the urban water system.