Microfiber prevalence and removal efficiency of textile effluent treatment plants in Bangladesh

Bangladesh is one of the hubs of the textile industry in the world; consequently, microfibers are an emerging threat to the aquatic ecosystem. Traditional effluent treatment plants (ETPs) might not be capable of removing most emerging pollutants like surfactants, dyes, and additives, including microfibers, and the textile industry may be a major source of microfiber pollution through products and ETPs. This study investigated the eleven woven, knit, and denim industries' ETP microfiber abundance and removal efficiency. The average (range) of microfibers found in influent, effluent, and sludge samples was 615.45 ± 377.52 particles/L (170−1460), 212.72 ± 80.14 particles/L (130−380), and 10545.45 ± 7989.54 particles/kg (4400−31000), respectively. The abundant shape was fiber, and most microfibres had sizes between 0 and 100 μm. Eight distinct colors of microfibers were found in the samples; black was the most abundant color among all the samples, followed by brown and blue. The studied ETPs showed a 23.52 % to 82.19 % microfiber removal rate, which is not satisfactory for minimizing pollution. The Fourier transform infrared (FTIR) analysis revealed that the main polymers in the samples were nylon, ethylene-vinyl acetate (EVA), polyethylene terephthalate (PETE), acrylonitrile butadiene styrene (ABS), cellulose acetate (CA), low-density polyethylene (LDPE or linear LDPE), and high-density polyethylene (HDPE). The contamination factor (CF) and pollution load index (PLI), which assess ecological risks, showed that samples were moderately to very highly contaminated by microfiber and could pose a threat to the aquatic ecosystem. The findings would help identify transformative challenges required for minimizing microfiber pollution from industrial sectors and improving ETP systems.