LIFE GreenLED: 18 months of advancing rainwater reuse in cities!
Did you know that FieldFactors 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.
🌎 Why this project matters
With climate change reducing freshwater availability, cities must rethink their approach to water management. That’s where LIFE GreenLED comes in: integrating innovative circular water strategies for rainwater harvesting, treatment, and reuse in cities.
Our goal? To make rainwater safe for urban applications—from irrigation to ornamental water features—while reducing dependence on potable water.
💡What we’re doing
GreenLED is more than technology. It’s an innovative concept inspired by nature that harnesses the power of light to transform urban water management.
At the core of this project lies the synergy between two advanced technologies:
BlueBloqs: A smart biofiltration and storage system that removes pollutants from rainwater and stores it underground.
UVC-LED disinfection: A cutting-edge, light-based treatment that ensures safe water reuse.
Over the next two years, these solutions will be tested in three real-world settings in Spain and the Netherlands, demonstrating their potential to support climate resilience and sustainable cities.
18 months in, we’re excited to share our progress!
🌱 Milestone highlights
🏗 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.
GreenLEd system for treatment, underground storage and disinfection of rainwater before reuse in greening buildings in Lage Zijde, Alphen aan den Rijn.
Sampling groundwater in Lage Zijde, Alphen aan den Rijn. Photo E. Boer (FieldFactors)
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.
GreenLED system for treatment and disinfection of rainwater for an urban pond in Parque Oeste, Los Ahijones, in Madrid.
Start of construction works for rainwater collection in Lage Zijde, Alphen aan den Rijn.
Construction started in January 2025. The systems 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.
GreenLED system for treatment and disinfection of rainwater for an urban pond in Parque Oeste, Los Ahijones, in Madrid.
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!
🏗 What’s next?
The construction works will continue until summer 2025. After launch, the pilot systems will undergo two years of monitoring by Universidad Politécnica de Madrid and Delft University of Technology.
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LIFE GreenLED (LIFE22-CCA-NL-101114560) is funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or The European Climate, Infrastructure and Environment Executive Agency (CINEA). Neither the European Union nor the granting authority can be held responsible for them.