Danish Urban Water Retention (UWR) developed an innovative modular system, assembled like Legos, to manage stormwater and prevent flooding in urban settings. The material used in the modules is a customized recycled PP from Polykemi and Rondo Plast, developed to meet tough specifications and enhance the product's sustainability profile. The system won an award in its category at the 2025 Aquatech Innovation Awards in Amsterdam.
Success thanks to material composition
UWR's product consists of square modules that are placed next to and on top of each other underground, to create either storage or transportation of stormwater, thereby reducing the risk of flooding in urban areas. To support heavy weight from above, a customized recycled plastic was needed that could meet high stiffness requirements, which Polykemi and Rondo Plast were able to provide. The base material in the modules is a commonly used material in the automotive industry, which they have customized and strengthened to fit this specific product.
“The material is a REZYcom PP with a specific polymer composition, reinforced with glass fiber, which together provide the necessary stiffness. We also have excellent repeatability with the material, so UWR will experience the same performance with every delivery,” says Fredrik Holst, Product Manager for Recycled Materials at Polykemi and Rondo Plast.
Part of UWR’s product success is directly linked to the material.
“We would not have achieved the success we have with our product without the material composition. There's no need to debate if it’s brilliant - it is brilliant!” says Christian Rosenvinge, Production and Procurement Manager at UWR.
Reduced CO2 footprint by 65-70%
UWR’s product aims to increase cities’ resilience to climate change while simultaneously pursuing other sustainability goals.
”We achieved such a high proportion of recycled plastic, reducing our CO2 footprint by a remarkable 65-70%,” says Christian Rosenvinge.
This wasn't the only sustainability benefit realized through recycled material.
”The stiffness and strength we achieved mean UWR's clients can place their cubes relatively shallowly in the ground, which has the effect of reducing the amount of soil that needs to be transported away - a win in the overall sustainability concept, but it should also provide an economic advantage for UWR's customers,” says Fredrik Holst.
Collaboration to find the right material
The journey to find the right material was a collaboration between the customer and the supplier, where being geographically close provided benefits throughout the process.
“UWR took the chance to visit us together with their clients to see our production and let our technical experts demonstrate the material on-site. As a kind of extra quality assurance,” says Fredrik Holst.
From the beginning, UWR aimed to use material based on recycled raw materials, but it took some effort before the two sides found exactly the right one.
“We worked closely with the lab at Polykemi, and in the end, we found a recycled plastic material that met all our requirements,” says Christian Rosenvinge.
The modules in UWR’s system have a lifespan of 75 years - compared to conventional solutions on the market today, where the lifespan is usually around 25-30 years.
“Apart from how the modules are designed, the customized material is a big reason why the lifespan is so good,” says Christian Rosenvinge.
Winner of the Aquatech Innovation Awards 2025
In March 2025, UWR won the Aquatech Innovation Awards in the ”Transport and Process & Control” category for their innovation.
”Aquatech is the world's largest trade fair for water technology and the award is basically the water industry's answer to an ‘Oscar’. Winning the award is a great sign of quality. We started production in October 2023, and now have ongoing projects with deliveries to Denmark, Norway, the UK, Portugal, the Netherlands, and Germany. This may lead to more clients discovering our solution,” says Christian Rosenvinge.
Polykemi follows UWR’s journey as a proud supplier.
“We're thrilled to be part of this collaboration and follow UWR in their success. They’ve earned this spotlight, and their fantastic system really makes a difference in society! For us, it’s proof that we’re doing the right things as a supplier,” says Fredrik Holst.
