The primary concern regarding the sustainability of the urban water cycle remains the performance of water supply systems. This, in turn, is determined by the functionality and sustainability of the system components, such as the pipe networks, pumps, and other appurtenances, which must be analyzed from an environmental perspective. The aim of the present study is to analyze the sustainability of two different types of water supply pipe materials that are commonly used, polyvinyl chloride and high-density polyethylene, using a comparative Life Cycle Analysis methodology. The functional unit was established in accordance with the water supply system that serves an Italian metropolitan city with a dimension of 9240 km, as one meter of water supply infrastructure, with 40 years as a life span. A cradle-to-gate analysis was conducted, starting from the production phase of the water pipelines to the maintenance phase, excluding the end of life and disposal phases. The chosen methodology was CML, justified by the fact that the results are more understandable and reproducible. Results comparison revealed a higher environmental impact during the production phase, while the maintenance phase had a very low impact. Notably, PVC pipe in comparison with HDPE material had a higher impact, except in two categories of impact: abiotic depletion and photochemical oxidation. The study contributes to the future development of alternative approaches for sustainable and eco-efficient water supply infrastructure designs and materials.

This study examines how collaborative governance and shared accountability, situated within a multi-level and multi-dimensional institutional setting, can advance the localization of the United Nations 2030 Agenda for Sustainable Development. Since localization demands aligning global priorities with local contexts through a nuanced understanding of needs and interests, it calls for innovative institutional mechanisms and collaborative dynamics. Focusing on the Metropolitan City of Bologna and its 54 municipalities, the research adapts an existing framework of collaborative governance to investigate the interplay between multi-dimensional and multi-level institutional arrangements as well as retrospective and forward-looking accountability systems as elements to advance sustainable development in multi-faceted urban settings. The case study reveals how collaboration, shaped by multi-stakeholder dialogue, and exacerbated by consensus-oriented and deliberative processes, strongly influence the ability of stakeholders to have a comprehensive grasp of the underlying functional linkages, focusing not only on their cherry-picked goals but also on evaluating integration efforts seriously, thus encouraging a shared sense of responsibility towards a sustainable future. Nonetheless, challenges related to data availability and interoperability persist, continuing to hinder the symbiotic effectiveness of accounting systems and shared accountability mechanisms.

The circular economy, as a new model of waste management through energy self-sufficiency and valorisation, can be applied to wastewater treatment plants (WWTPs). Screening waste from WWTP pretreatment is the only waste that is not energetically recovered and thus constrains the achievement of zero waste. Previous studies demonstrated the technical feasibility of producing solid recovered fuel (SRF) from this waste. Environmental benefits, including waste reduction, resource conservation, or reduced greenhouse gas emissions are analysed in this work. Environmental impact is quantified using the life cycle assessment (LCA) methodology through the SimaPro 9.2. software and the CML-IA baseline v3.08 impact methodology, that propose 11 impact categories. Five scenarios were established to compare current landfill disposal with the production of densified and non-densified SRF using solar and thermal drying. Within the system boundaries studied, from waste generation to SRF production, results show that landfill is the most environmentally damaging option while producing non-densified SRF using solar drying is the most environmentally viable scenario.

Growing pressures on water resources, exacerbated by climate change, resource depletion, and population growth, underline the need for sustainable and energy-efficient wastewater management. Wastewater treatment plants (WWTPs) are among the most energy-intensive elements of the Integrated Water Service, and their environmental performance depends on infrastructure design, resource availability, and treatment configuration. Improving resource efficiency while reducing energy demand and environmental impacts is therefore a priority for water utilities seeking innovative decision-support tools. Within the national project “WATERGY—Energy Efficiency of the Integrated Water Service”, this study proposes a life-cycle-based framework to assess the sustainability of technological interventions in WWTPs. A comparative gate-to-grave Life Cycle Assessment (LCA) was applied to the municipal WWTP of Potenza (Southern Italy). Three sludge End-of-Life Scenarios were assessed: the current landfill-based configuration, an enhanced oxygenation–nitrification setup, and anaerobic digestion with biogas-based cogeneration. Compared to the current scenario, anaerobic digestion with cogeneration reduces Global Warming Potential by 17% and decreases freshwater ecotoxicity by approximately 30%. Compost production shows the highest reduction in ecotoxicity (−51%) but increases fossil resource depletion and acidification due to higher energy demand. Overall, energy recovery pathways, particularly anaerobic digestion with cogeneration, provide the most balanced environmental benefits, supporting more sustainable WWTP operation within the Integrated Water Service.