Microplastics released during washing cycles remain a source of environmental concern, even after wastewater treatment. According to the German Institute for Textile and Fiber Research Denkendorf (DITF), between 12 and 1400 mg of microplastics can enter wastewater per wash cycle and kilogram of laundry. While treatment plants remove about 99 percent of these particles, the remaining fraction is discharged into natural water bodies, where it may affect ecosystems and human health.
To address this issue earlier in the process, DITF has developed a textile-based microfilter. The system consists of multiple layers of polypropylene fabric combined with a three-dimensional spacer fabric. Filtration occurs across three stages, with each layer designed to have progressively finer pores. This structure allows the system to capture microplastic particles as small as 1.5 μm.
Field tests were conducted in both an industrial laundry and a municipal wastewater treatment plant. During these trials, the cascade filter achieved separation rates ranging from 89.7 to 98.5 percent. The system operates effectively at low water pressure and includes a cleaning mechanism that uses compressed air for backwashing.
According to the researchers, the filter cake accumulates on the spacer fabric, which extends the time between cleaning cycles. This design increases the operating time of the filter element by approximately 155 percent. The system is also described as compact and adaptable, with the ability to scale for different applications.
DITF states that the filter could be applied beyond washing processes, with potential use in other filtration scenarios. The design aims to provide a cost-effective method for reducing microplastic discharge into the environment.