Mitigating Microfiber Pollution in Laundry Wastewater: A Case Analysis

Synthetic fibres, owing to their durability, elasticity, non-wrinkle nature, and cost-effectiveness, have become ubiquitous globally. However, the widespread use of synthetic fibres has raised concerns about microfiber pollution, particularly in laundry wastewater.  While source reduction could be considered the main management method to prevent microfiber-induced pollution, advanced technology is essential to manage the discharge of significant quantities. The present study focuses on analysing the efficiency of a laundry wastewater filtration technique and its applicability for large-scale washing machines to control microfiber emissions during the washing process. Samples were taken from the front-loading washing machine (capacity: 23kg) equipped with a treatment unit, filled with 12 kg of clothing. ent unit. The 1L sample was collected from both untreated and treated water outlets during four washing cycles until the end of the wash. These samples were filtered through a 100 µm net to collect the microfibers. Catalytic wet peroxide oxidation and density separation were employed to extract possible microfibers, which were then collected on a membrane filter paper (0.45 µm) and observed using a stereo microscope. In untreated laundry water (n=4) 10028.7±1420.8 of microfibers per litre were identified. Conversely, treated laundry wastewater (n=4) exhibited a significantly lower count, with 191.5±109.4 pieces per litre of microfibers. Predominantly, microfibers of black and white/transparent colours were observed, with smaller quantities of red and blue microfibers. The treated wastewater samples showed a similar dominance of black and white/transparent microfibers. Further, it was revealed that 1kg of cloths can generate 336,833 microfibers per wash and it was reduced to 6,367 microfibers after the treatment. The filtration technique demonstrated an impressive efficiency of 98.09%, indicating a remarkably high microfiber filtration capacity. These findings underscore the potential of such filtration techniques to substantially reduce microfiber emissions from laundry wastewater, presenting a promising potential for widespread implementation in mitigating environmental pollution from microplastics.