A novel approach for rapid quantification and length distribution of microfibers released during domestic laundry

Textile abrasion releases microfiber pollutants, a significant environmental concern, primarily from domestic laundry. A method to directly quantify microfibers in water and calculate their length distribution is lacking. This study aimed to develop a rapid method for quantifying microfibers and to derive a density function of their length distribution. We explored the feasibility of the method through small-scale experiments, assessed the accuracy and repeatability of the method and verified the method using actual laundry wastewater. The correlation between the mass concentration and absorbance of two types of common microfiber suspensions was studied and a regression equation was established, showing the fitting effect was satisfactory. As a result, it was found that the absorbance values are linearly related to the mass concentrations. The comparison of microfiber release during full-scale washing showed spectrophotometry and counting method can both be used to quantify microfibers. In addition, by using kernel estimation, we obtained the probability density function and distribution function of microfiber length. The integral results of the kernel function of these two types of fiber for 5 washing cycles are all around 0.9. These functions are convenient for the development of future filtration devices and assessing environmental impact.