LIFE GreenLED: 18 months of advancing rainwater reuse in cities!
Did you know that G-AQUA (Universidad Politécnica de Madrid ) is a proud member of the LIFE GreenLED project?
Co-financed by the European Union’s LIFE programme, this initiative is revolutionising urban
water management through nature-based and LED-powered rainwater treatment technologies.
With three demonstrator systems in Madrid (ES) and Alphen aan den Rijn (NL), we are proving that smart water solutions can support greener, more climate-resilient cities.
In this article, we share key milestones, the latest updates, and what’s next for scaling up rainwater reuse across Europe.
GreenLED demonstration in Alphen aan den Rijn (Netherlands)
In Alphen aan den Rijn, the GreenLED system is part of a major effort to reduce heat stress
and urban flooding. The city is implementing 50,000 m² of green facades and roofs, which
will be sustained by 15 million liters of reused rainwater annually—collected, treated, and stored through two GreenLED systems.
One of these systems is being developed in Lage Zijde, where rainwater runoff from 21,000 m² of paved surfaces is collected through an existing stormwater sewer. This water is directed to a 600 m³ underground buffer tank, where it is temporarily stored before treatment. Using BlueBloqs biofiltration, the rainwater is purified before being infiltrated into the subsurface via an infiltration well. When needed, water is extracted and treated with a UVC-LED disinfection unit before being supplied to building owners for irrigating green roofs and facades. Additionally, the treated water will feed an ornamental water feature, reducing potable water consumption in the city center.
In Hoge Zijde, another GreenLED system is being installed to capture and treat surplus
surface water from the nearby Omloopkanaal. During winter, excess water is collected and
directed through a biofiltration system to remove pollutants before it is infiltrated into the
subsurface. In drier months, the stored water is pumped back up to irrigate green roofs,
supplying up to 8,000 m³ of water annually. A UV-LED disinfection unit ensures the water is
safe before reuse, supporting urban greenery and enhancing climate resilience.
Construction started in January 2025. The projects are expected to be operational by summer 2025!
GreenLED demonstration in Los Ahijones, Madrid (Spain)
In Madrid, a GreenLED system is being integrated into Los Ahijones, a new urban development in the city’s southeast, creating a sustainable water source for an urban pond.
Los Ahijones will feature 944,976 m² of green areas, including two major parks. The area incorporates sustainable urban drainage systems (SUDS) such as permeable pavements and tree-box retention systems, which capture, retain, and infiltrate rainwater locally. The GreenLED system, located in Parque Oeste, will take this approach further by treating stormwater collected through the SUDS network.
A 112 m³ underground retention tank stores rainwater before being treated with a BlueBloqs biofilter and UV-C LED disinfection. The treated water will be used to supply an ornamental
pond, meeting evapotranspiration demands of up to 240 m³ annually. To maintain water quality, a biofilter-integrated waterfall feature will ensure continuous circulation, improving aeration and reducing algal growth while also enhancing visual and thermal comfort in the
park.
Since rainwater alone may not be sufficient during dry periods, the system is also designed
to treat reclaimed water from Madrid’s municipal network. This dual-source approach ensures a year-round, sustainable water supply for high-quality urban applications.
Construction began in January 2025 with the development of the SUDS network, and the
GreenLED system is expected to be operational by summer 2025. The GreenLED system will be operated by the City of Madrid and the public-private partnership Junta de Compensación Urbanización del Este Los Ahijones.
Meet the GreenLED team
The LIFE GreenLED project is powered by six key partners across Spain and the Netherlands:
Spain
● Junta de Compensación Desarrollo del Este Los Ahijones – Urban development agency
● Universidad Politécnica de Madrid – Research institution
● APRIA Systems – Technology provider
Netherlands
● City of Alphen aan den Rijn – Municipality
● Delft University of Technology – Research institution
● Field Factors B.V. – Technology provider
Together, we’re making water sustainability a reality!
Stay Updated!
Want to follow our impact journey and get the latest updates?
Follow LIFE GreenLED on LinkedIn: www.linkedin.com/showcase/life-greenled
GreenLED is co-funded by the LIFE programme of the European Union.
Grant Agreement No. LIFE22-CCA-NL-101114560
The contents of this website are the sole responsibility of the authors and do not necessarily reflect the opinion of the European Union.
