GreenLED: a year of scaling rainwater reuse in cities
GreenLED consortium in Los Ahijones, Madrid.
The LIFE GreenLED project aims to scale rainwater reuse in European cities by developing a unique solution that enables the replacement of potable water with locally collected rainwater. Approaching the first year of implementation, the GreenLED consortium met in May in Madrid to share the progress of this unique project. GreenLED, co-funded by the EU funding instrument for the environment and climate action LIFE, is developing two demonstration sites in Alphen aan de Rijn, The Netherlands and Madrid, Spain to save approximately 10 million liters of potable water every year. The consortium has been working in close collaboration with water authorities, architects and end users to develop the pilot sites and ensure compliance with local regulations. GreenLED will create a reference in climate adaptation by demonstrating that rainwater can be a reliable source of water to meet growing urban water demand, meeting the regulatory constraints for public health and rainwater reuse in cities.
Innovation in urban water management
Due to the changing climate, the security of freshwater supply is uncertain and a growing problem. Creating alternative sources for a sustainable water supply is therefore crucial to sustain the quality of life in the city. One of the biggest challenges for rainwater reuse in public spaces and residential areas is the lack of cost-effective and environmentally friendly alternatives for proper water treatment.
In 2023, the GreenLED consortium consisting of FieldFactors, Delft University of Technology (TU Delft) and the municipality of Alphen aan den Rijn in The Netherlands, in collaboration with the Spanish partners Polytechnic University of Madrid (UPM), the public-private partnership Junta de Compensación Los Ahijones in Madrid and water technology company Apria Systems received a €3 million grant from the EU LIFE program to develop a scalable solution for rainwater reuse for urban applications.
The GreenLED project integrates natural purification and underground storage technology with an energy-efficient UV-LED disinfection. In this way, the project offers an integrated and sustainable solution for the treatment, storage and reuse of large quantities of rainwater without endangering public health. The project focuses on removing contaminants so that the water is safe for use in close human contact applications, such as irrigation of green roofs, filling fountains and urban ponds, swimming and playing and for industrial processes. The innovative rainwater management solution will be implemented in two demonstration locations in the City Center of Alphen aan den Rijn, in The Netherlands and in Los Ahijones, in Madrid.
First project results
During the first year of implementation, the consortium has established the project foundation, made strides in integrating biofiltration and aquifer storage with UV-LED technology, developed and applied an impact assessment framework and engaged with key stakeholders.
Los Ahijones in Madrid will fill an urban pond with rainwater to save drinking water
In the city of Madrid, the innovation will be installed in Los Ahijones, one of the largest urban developments of the city of Madrid. Rainwater collected on site will be used to supply an urban pond, after treatment with the BlueBloqs system and UV-LED disinfection.
In dry periods, the Ahijones demo site will also use reclaimed water for high quality applications, so that there is sufficient water supply all year round – the first experiment of this type in the city of Madrid. If proven successful, the City of Madrid has the ambition to subsequently enable the reuse of rainwater for non-potable urban uses across the city.
Collaboration with Junta de Compensación, CA14 - the architecture firm responsible for the development of the green areas in Los Ahijones-, and technicians from the City of Madrid has been crucial in successfully integrating the solution in the urban development project and ensuring compliance with regulations and maintenance requirements.
GreenLED technical concept in Demo Los Ahijones, Madrid.
In Alphen aan den Rijn rainwater will be used to create 50,000 m2 of urban green
To reduce the urban heat island effect in the paved city center, the municipality of Alphen aan den Rijn will install 50,000 m2 of green facades and green roofs. To provide greenery with water, paved surface in the city center will be disconnected from the sewerage system, to provide 15 million liters of rainwater for reuse annually. With the BlueBloqs technology, collected rainwater is purified and stored underground. A UV-LED post-treatment installation will purify the abstracted water before it is used for irrigation of green roofs and facades in buildings.
A crowded city center has proven challenging for the integration of new solutions. The project group has been working with municipal technicians to tackle the challenges related to conflicting land use priorities and spatial constraints.
The design for the implementation of both demo sites will be completed in the coming months, with construction works planned to start at the end of 2024. The pilot locations will be continuously monitored by the Technical Universities of Delft and Madrid to evaluate the impact and effectiveness of the solution.
The integration of the BlueBloqs technology for rainwater treatment and underground storage, supplemented with UVC-LED disinfection will enable the transition to water-neutral and climate-adaptive buildings and urban developments in the Netherlands, Spain and other European regions.
GreenLED technical concept in Alphen aan den Rijn, NL.
Do you want to know more about this ambitious project?
Get in touch with Thomas, our project lead. He would love to tell you more about GreenLED.