Design and Sustainability Assessment of Scenarios of Urban Water Infrastructure Systems

The basic concept of today's infrastructure systems for water supply and wastewater treat-ment dates back more than 100 years. In the paper it is questioned whether the traditional concept, which is characterized by centralized structures, mixing of wastewater streams of various qualities, and open loop design is suitable to fulfill the new requirements in terms of sustainability. The results of an interdisciplinary analysis and assessment performed within the ongoing project AKWA-2100 for two German municipalities as case studies is presented. Using the scenario approach three scenarios are developed with a long-term perspective of 2050 plus to integrate technological, organizational, and institutional innovations into cohe r-ent alternative urban water systems with improved eco-efficiency. Since water infrastructure systems strongly affect the sustainability of water resources management the scenarios are evaluated with respect to their sustainability using a total of 44 criteria. In an iterative proce-dure supported by the Analytic Hierarchy Process the criteria were structured and the ind i-vidual assessments of the AKWA-2100 research team members were integrate into a joint assessment. Preliminary results indicate that infrastructure scenarios with decentralized com-ponents, closed loops of water and other materials and specific treatment for different quali-ties of wastewater prevail with regard to most of the criteria