To accelerate the transition to a circular economy, the European Commission (EC) promoted alternative water resources in the Horizon 2020 Framework. To increase water use efficiency and reuse, the call CE-SC5-04-2019 funded five different projects (B-WaterSmart, WIDER UPTAKE, REWAISE, ULTIMATE and WATER-MINING). These five projects run from 2020 to 2025, with a total budget of 84 M€, and EU contribution of 71.5 M€, and share the objectives of identifying alternative water sources, reducing water consumption, increasing use efficiency, recovering valuable materials from water, producing carbon-free water cycles, and increase resilience to climate change. To leverage the resources from EC wisely, the five coordinators decided to share common knowledge, promoting synergies and avoiding reinventing the wheel. This resulted in the creation of a cluster called CIRSEAU, to connect 143 partners in more than 20 countries, reaching almost all members stated of the European Union (EU), in addition to countries like India or Ghana outside the EU. Building on the alliance formed to foster cross-promotion, communication alignment, and impactful outreach for the five projects funded under the EU research call on building a water-smart economy and society (CE-SC5-04-2019). To reach the outcomes of this CSA, additional experts and partners have been asked to complement experience and competence of CIRSEAU. This consortium brings together 10 partners from 6 countries (BE, DE, ES, GR, NL and NO) to provide multidisciplinary expertise and trans-nationality required to foster cross-promotion, communication alignment, and allow impactful outreach to public authorities, policy makers, and standardization bodies. The main objective of the CSA is to build a collaborative ecosystem that generates strong synergies among the Circular Water Economy Community formed across EU projects, and to expand the CIRSEAU cluster to enhance market uptake, collaboration and knowledge sharing.

Climate change events, such as droughts and floods, are affecting water availability and the global economy. Decentralized water management (DWM) systems can enhance water reuse by treating wastewater near its source and repurposing it for suitable uses. However, widespread adoption requires greater awareness of its benefits, technical demonstrations, and policy adaptation. The WATERSENS project aims to demonstrate the benefits of six DWM technologies and provide an integrated decision framework to help water authorities and stakeholders select, design, and integrate these systems. The selected technologies cover diverse water resources and uses, addressing various geographic and economic contexts. They include floating wetlands for wastewater and stormwater treatment, biofilters for river pollution removal, phototrophic bacteria and biofilters for urban wastewater, green walls for greywater treatment, and green roofs and cisterns for stormwater collection. Quality control procedures will be followed, and emerging contaminants will be characterized. The impacts will be evaluated through LCA, LCC, and social LCA, supported by a risk management model to provide data-driven evidence of the benefits. WATERSENS will also identify barriers in different regions and propose a governance framework based on a cost-benefit analysis and the evaluation of administrative challenges. This will be integrated into a Decision Support System (DSS) platform, driven by AI, which will also include a DWM catalogue, GIS tools, and climate change models, aiding water management stakeholders in making informed decisions.

D4RUNOFF overall goal is to create a novel framework for preventing and managing diffuse pollution from urban water runoff through the data driven design of hybrid nature based solutions (NBS) adapted to the current and future risk scenarios solutions. This innovative approach will support water utilities, urban planners and policy makers in defining urban runoff and storm water management plans to enhance the quality of the water discharged to water bodies, considering the Climate Change. D4RUNOFF will have the following specific objectives (SO): - SO1 Increase the knowledge regarding urban runoff pollution sources and the impacts through the development of novel high-resolution suspect and screening & non target screening NTS methods for Contaminants of Emerging Concern (CECs) detection and identification of the major CECs and relevant pollutantspresent in storm water source and assessing their fate in NBS - SO2 Development of cost effective advanced online sensors for targeted CECs, metals and microplastics for improving the monitoring of the water pollution derived from urban runoff - SO3 Enhancing the implementation of advanced preventive and mitigation strategies to reduce diffuse pollution through the development of and innovative multiple-criteria decision analysis (MCDA) methodology integrated in Geographical Information System (GIS) for hybrid NBS design - SO4 Development of a risk assessment and mapping methodology to identify diffuse pollution hotspots for specific sites & considering climate change effects. - SO5 Development of an AI based platform to facilitate the development of effective urban runoff and storm water management plans based on informed decisions - SO6 Implementation and validation of D4RUNOFF approach in 3 case studies and 5 replication sites - SO7 knowledge transfer and engagement with stakeholders, including civil society