Weft-knitted media development for technical application for wastewater post-treatment: Effect of spatial sample shape and porosity

The innovative designs come from the authors’ idea to similarity with commercially usable plastic media (AnoxKaldnes), which could be replaced with weft-knitted fabric with loose loops required for water flow during wastewater treatment. By a tailored mass fraction of polypropylene and polyester yarns, the necessary purpose of floating the sample due to the lower density, mimicking water, can be achieved. The textile-based microfiber structure supports bacterial attachment. The bacteria surface covering is examined with image analysis during the first period of the experimental bioreactor post-treatment process with the aim of helping media development. The surface bacteria covering is tracked in the location of media shape (inner, outer, held and transfer loops), and samples with high single jersey porosity improved the cell capture. Regarding initial adhesion and quick-up colonization process (advantage of fiber application), the results concerned yarn count and knitting parameters and recommended structure and patterning elements. Experimental tests did not confirm the necessity of openings in the media structure. A highly porous weft-knitted media of the spatial shape, including the simple pipe shape, could be an alternative to a plastic one, which would benefit while maintaining the existing infrastructure of the wastewater treatment process.