Municipal water may contain impurities such as dissolved substances from aging pipes, microplastics, chlorine, or bacteria. In Finland, water wells in summer cottages can also have a varying amount of dissolved and oxidized metals. To address these issues, AQVA Finland (AQVA) has developed commercial water filtration systems suitable for treating: shower water, tap water in municipal networks, borehole and well water and even sea or lake water.

Today, AQVA manufactures more than 90% of its filters in-house. The actual production processes for the filters are relatively straightforward, whereas developing new filter materials and improved methods requires a more scientific approach. Thus, AQVA and VTT Technical Research Centre of Finland have joined forces to seek locally sourced, commercially available bio-based materials that can be used to further tailor and enhance the filtration products while also providing more regional independence, self-sufficiency and lesser reliance on energy-intensive and environmentally harmful materials and processes.

This work is focused on the tap water filter based on activated carbon (AC).AC is a well-established and proven material in filter manufacturing, and much of the existing production machinery has already been specifically designed and optimized for its use. For this reason, AC was selected as the base material, with the goal of incorporating new bio-based additive materials into it, as well as exploring alternative, more locally sourced base materials to replace the AC at least partially.

Here, VTT brought their expertise on biobased materials research and engineering to identify and prepare new materials with added functionalities and suitable properties that are suitable for processing into the final product by AQVA, followed up practical testing on the commercial-scale production machinery to fine-tune and adapt the manufacturing process accordingly.

Based on screening of materials, we found that the incorporation of small loadings of cellulosic nanomaterials with high specific surface area and large amount of functional groups, such as cellulose nanocrystals, enables precise tuning of pore structure, density, and interfacial interactions with chemical groups, molecules, atoms, or ions in the medium, thereby enhancing the selective removal of targeted chemical species from water. Moreover, we found that replacing AC with wood-based biochar not only improves the filtration efficiency, especially in terms of oxidized iron, of the already successful product produced in commercial scale.

All the new materials are commercial and available from Finnish forest residues, allowing the use and upcycling of local forest-based materials and side streams with a competitive price, while providing a tailorable porous structure that can be activated and modified based on the specific needs of the end use application. Overall, the approach supports Finland’s and Europe’s transition toward bio-based and energy-efficient purification technologies, contributing to both environmental and supply-chain sustainability.