Nexus analysis and life cycle assessment of regional water supply systems: A case study from Italy

Ensuring reliable access to water sources is an emerging issue being currently addressed by governments and international communities. However, local conditions play a primary role in determining requirements for urban water supply systems and cascade implications due to simultaneous interlinkages with complementary resources such as energy. As such, addressing sustainability in water management comes through quantitative evaluation modelling and assessment. To this aim, nexus analysis and life cycle assessment methodologies are applied to the drinking water supply system in the Romagna region (Italy). Our research provides detailed characterization of the involved material and energy flows, which is used as a basis for determining water-for-energy and energy-for-water results, and to conduct environmental assessment for complementary impact categories by withdrawal, treatment, and distribution processes. The results show that the energy needed to produce drinking water ranges from 0.27 MJ to 2.53 MJ per cubic meter of water delivered. Water deriving from the artificial basin and treated following a conventional technology turned out to be both the less energy intensive and the less impacting process. Overall, the study provides an exhaustive comparison of the environmental impacts of different water production alternatives, which may ultimately support decision-makers and local communities to the planning of strategies for optimized and long-term reliable access to water resources.