Creating fabrics and pottery from wastewater

Dutch water authorities see themselves more and more as energy and resource factories, in addition to cleaners of wastewater. The Rijnland & IJssel water authority and Netherlands’ dairy multinational FrieslandCampina have joined efforts to develop a multifunctional gel from recycled wastewater. The substance can be utilised as raw material for textiles and porcelain.

Kaumera raw materials plant in Zutphen

Kaumera raw materials plant in Zutphen

The water authorities have been recycling wastewater for many years, for instance, through the  extraction of phosphor to be reused as fertilizer. However, the authorities see themselves not solely as cleaners of wastewater, but also as generators of energy and raw materials.

Dairy manufacturer FrieslandCampina and water authority Rijn & IJssel took the recycle process one step further and co-created – based on research by Delft University of Technology - a multipurpose gel from used household water, labelled Kaumera (Maori for chameleon).

Coating applications

The recycling process involves extracting slush from polluted household wastewater, to be used as a binding agent for many products - from fabrics to pottery. That same slush can now be processed into a raw material for a plastic coating replacement. The coating is used to laminate seeds and fertilisers that act as a buffer to release their nutrients slower, allowing seeds to germinate better.

Mixing the gel with clay and adding it to reinforced concrete, can improve the hardening process and reduce corrosion in steel. The same coating can be applied to paper to make it water resistant.

Additionally, fusing the gel with wood fibres or clay, creates fire resistant sewing threads and plastic products which can retain their shape up to 180 degrees Celsius. The gel is a good alternative for other types of coatings, which usually contain plastic-based oils that are hard to break down when penetrating the soil.

Sustainable advantages

A completely new wastewater purification method is used to extract the Kaumera gel. Currently, most of the water is purified using oxygen in giant basins. The Kaumera method uses bacteria to clean the water, also known as the Nereda-process. As a result, the waste degradation is more efficient and uses less energy. Added to that, the process occurs in compact basins, which saves factory space.

Recycling polluted wastewater has more sustainable advantages, water authorities only have to dispose 20%-35% of the leftover slush and therefore use less energy and emit less CO2 during the wastewater treatment process.

The Kaumera Nereda gum took the overall award at this year's Aquatech Aqua Innovation Awards.

Although more research needs to be done to make the Kaumera gel a viable product, it is one step closer in making wastewater slush a circular and sustainable alternative for many raw materials.