This study summarizes the development of textile-based filters composed of microporous polypropylene fabrics or highly porous three-dimensional (3D) warp-knitted textiles and provides insights into their fabrication, exploration, and performance assessment across several application areas.

Such 3D textiles are well suited as carriers for the immobilization of industrially important microorganisms due to their high effective surface area and excellent mechanical, biological, and chemical resistance. Immobilizing microorganisms on the flexible textile surface allows their microbial activity to be maintained, making these materials highly suitable for efficient wastewater purification in biological wastewater treatment systems, for biological greywater recycling to relieve pressure on water supply systems, as well as for exhaust air purification aimed at reducing ammonia emissions in animal farming and enabling nutrient recovery using algae. For example, the integration of a 3D textile-based bioreactor as a component of a greywater remediation cascade in a mid-size residential building enabled an accelerated reduction of both water turbidity (< 0.5 NTU) and chemical oxygen demand (COD > 90%) within only 6 hours.

A further application of the 3D textiles is their use in a textile-based cascade filter for the removal of microplastics from industrial laundry effluent. The 3D textile sandwich structure promoted filter cake formation, allowing for extended backwash intervals and effective recovery of filtration capacity (> 89%). The innovative use of 3D textile composites enabled a high level of microplastic removal while extending the lifetime of the filter media, thereby significantly contributing to the reduction of microplastic pollution in aquatic environments. Moreover, the scalability, space efficiency, and cost efficiency of the system make it a strong candidate for advanced wastewater treatment solutions.