Mainstreaming Decentralized Urban Water Management Solutions for Sustainable Cities

Climate change, rapid urbanization and other grand challenges increasingly force cities to rethink their urban (water) infrastructure. In particular, decentralized urban water management solutions, which can recover valuable resources close to the source are increasingly applied to remediate water scarcity, sanitation or environmental pollution challenges. Yet, although interesting demonstration projects with decentralized solutions (from here on labeled ‘decentralized UWM solutions’) are underway in several world regions, actors developing and implementing this transformative innovation are not effectively coordinating their efforts and sharing the latest knowledge. While effective technologies, business models, or regulative frameworks increasingly exist that could inform, inspire and improve similar activities elsewhere, details of local successes and failures are still (too) rarely shared or transferred across space. Drawing from experience on the mainstreaming of other transformative infrastructure solutions (like renewable energies, electric mobility or circular waste management), we posit that the global diffusion of decentralized UWM solutions has been significantly slowed down by this lack of interaction among key stakeholders, and the resulting lack of an effective innovation ecosystem. Against this backdrop, Eawag, UC Berkeley, and Blue Tech Research organized an international road mapping workshop in Zurich on June 12-14, 2023, aimed at creating a platform for exchange among leading firms, cities, regulators, researchers, funders and NGOs working on innovative decentralized UWM solutions. The workshop employed a structured road mapping exercise on how different decentralized UWM solutions could scale-up and mainstream in the next 10 -30 years. This document summarizes the motivation and rationale for organizing this event and presents key outcomes of the discussion at the workshop. The report first provides background information on the global state of the art and systematizes the different types of decentralized UWM solutions that are currently emerging globally. It then outlines pathways for mainstreaming three types of solutions discussed in-depth at the workshop: Building-scale non-potable water systems, district scale resource recovery systems, and decentralized nutrient management systems. Participants concluded that these three solutions are likely to diffuse in distinct mainstreaming trajectories determined by different key drivers, technologies, as well as institutional frameworks enabling or hindering effective resource reuse. At the same time, common challenges exist, including limited potential for realizing economies of scale, immature industry structures, insufficient coordination among key stakeholders, lack of supporting policies and regulative frameworks, as well as persistent lock-ins to long-established ways of doing things in utilities, governments and incumbent firms. The report systematizes these commonalities and differences and explores ways in which synergies between the different roadmaps could be leveraged. It then outlines concrete actions to be taken in the short- to mid-term future to turn the three solutions into mature options ready for use by utilities, urban planners, funders and policy makers in their quest to develop circular and sustainable cities.

source :

https://www.dora.lib4ri.ch/eawag/islandora/object/eawag%3A33039/datastream/PDF/Binz-2024-Mainstreaming_decentralized_urban_water_management-%28published_version%29.pdf