The SuspensionFlow project aimed to develop a biomimetic filtration solution to reduce microplastic emissions from domestic washing machines by transferring biological filtration principles into an industrially relevant technical application. The focus was on ram-feeding fish, whose gill structures operate according to cross-flow filtration principles that are inherently resistant to clogging and therefore well suited for fibre-rich suspensions such as washing machine effluents. This project is an advancement of a previous project which studied the biological principles underlying this specific filtration type and in which we developed a first option for a filter element. In the SuspensionFlow project presented here, we developed the underlying principle into a scalable filtration unit with higher filtration rate and we undertook IP activities.
First, we tested a whole range of particle types in different testing setups in order to develop a system which can filter more diverse particle shapes compared to the initial filter design. Computational fluid dynamics simulations and flow-channel experiments were combined to analyse flow patterns, particle trajectories, and filtration efficiency. This work led to the identification of several biomimetic filter structures achieving more than 80% microplastic retention, while avoiding rapid clogging. Subsequently, the most efficient biological principles were abstracted and optimised for industrial application and we tested this system, together with regular self-cleaning intervalls, under washing-machine-relevant conditions using fibres and particles representative of real laundry effluents. The biomimetic filters demonstrated stable volume flow, effective self-cleaning, and high retention efficiency, while outperforming conventional dead-end filters in terms of clogging resistance. A functional demonstrator and laboratory test stand was realised. We also explored biological solutions for aerosol filtration in order to identify mesh types and inlet shapes which might be beneficial for different filter shapes and particle sizes. As aerosol filtration happens under very different conditions compared to fluid filtration, this work is not yet finished but looks promising to advance the filter even more.
In the final phase, intellectual property, exploitation potential, and societal relevance were addressed. A German patent application covering the biomimetic filter element and filtration method was filed earlier and we entered discussions with the German patent office regarding the advancments made within the PoC. Market potential was identified as high due to increasing regulatory pressure and the significant contribution of synthetic textiles to global microplastic pollution. In addition, two publications resulted from this project.
Overall, the project delivered a validated, biomimetic filtration concept with strong potential for further industrial development and commercialization, contributing directly to the reduction of microplastic emissions and to European sustainability and zero-pollution objectives.
