Microplastics and nanoplastics are abundant in the environment, and the fate and impact of nanoplastics are of particular interest because of their small size. Wastewater treatment plants are a sink for nanoplastics, and large quantities of nanoplastics are ffscharged into surface waters through wastewater as well as stormwater effluents. There is a need to understand the fate and removal of nanoplastics during water, wastewater, and stormwater treatment, and this study investigated their removal on a bench-scale using synthesized nanoplastics (<400 nm) to allow controlled experiments. Plastic particles were created in the lab to control their size, and bench-scale dewatering devices were tested for their ability to remove these particles. Filtration with a 0.22 μm filter removed 92 ± 3% of the particles, centrifugation at 10,000 rpm (670,800 g) for 10 min removed 99 ± 1% of the particles, and ballasted flocculation removed 88 ± 3%. These results provide a general idea of the magnitude of the removal of nanoplastics with separation processes, and more work is recommended to determine the degree of removal with full-scale unit processes. Even though the removal was good using all three treatments, smaller particles escaping treatment may increase the nanoplastics concentration of receiving water boffes and impact aquatic ecosystems.

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Water (Switzerland)
Department of Civil and Environmental Engineering

Murray, A. (Audrey), & Örmeci, B. (2020). Removal effectiveness of nanoplastics (<400 nm) with separation processes used for water and wastewater treatment. Water (Switzerland), 12(3). doi:10.3390/w12030635