Water Permeable Tiles Made From Recycled Sludge

If you think of sludge, you think of a useless by-product. Dutch start-up Waterweg came up with a recycling process that turns this raw material into a circular and environmentally-friendly material for water permeable tiles.

Water permeable tiles made from recycled sludge

Water permeable tiles made from recycled sludge

Sludge is dredged from riverbeds to create deeper waterways and avoid rivers from overflowing. Dredging ships collect the mud, which is transported over road to a storage location. The transportation generates unnecessary CO2 emission and a lot of money and time is invested in an unwanted product.

Winning circular tile idea

Eva Aarts, founder of Rotterdam-based Waterweg, realised that the practice was environmentally untenable and came up with an idea that is not only good for the environment, but also creates a tile that is circular and economically viable. She submitted her idea to the BlueCity Circular Challenge and Circular Innovation Challenge, and won both. By winning these challenges, the company received support and know-how to further develop the sludge tile on a grander scale.

From sludge waste to tiles

Waterweg asked the Delfland Water Authority - who dredge  mud from many Dutch waterways – to use some of their leftover sludge. The company added limestone and,  compressed and heated the silt, resulting in dense thin strips that create a water permeable tile when pressed together.

Many cities and towns are usually paved with tiles and other hard surfaces, causing poor water drainage during heavy rainfall. The Waterweg-tiles are hard, but also permeable, which allows water to pass through the tile rather than runoff.  This facilitates good  water drainage in urban areas. In the future, sludge waste might also be used to create building materials for floors  and walls.

Waterweg’s next undertaking is to start manufacturing tiles on location using a mobile processing plant. The process will be as followed:  a dredging ship collects sludge waste while the mobile plant – located directly on shore - dewaters the mud. The process continues by pressing the mud into a mold, creating a circular permeable tile. This process will further reduce the economic and ecological costs of  processing the sludge waste.