We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Microplastic Particle Loads Discharged by Swiss Wastewater Treatment Plants
Summary
Swiss researchers measured tiny plastic particles in sludge from 51 wastewater treatment plants and calculated that these facilities still release billions of microplastic bits into rivers and lakes each year—roughly half a gram per person annually. While treatment plants filter out most microplastics, they aren't a complete barrier, meaning some plastic pollution still slips through and ends up in the water systems that eventually connect to our environment and food chain. This matters because it highlights a gap in current wastewater infrastructure that scientists are still working to understand and address.
High Resolution Image Download MS PowerPoint Slide The contribution of wastewater treatment plants (WWTP) to the loads of microplastic particles (MP) entering surface waters is debated intensively. We, therefore, quantified MP (>20 μm) in activated sludge from 51 Swiss WWTP to estimate the MP loads discharged through WWTP into surface waters. MP were identified by Fourier transform infrared spectroscopy. We used surrogate standards as a quality assurance/quality control measure and conducted an uncertainty assessment across the whole analytical chain. The MP number concentrations in sludge per gram total suspended solids (TSS) ranged from 900 to 22,000 MP gTSS –1, resulting in calculated mass concentrations between 10 and 1700 μg MP gTSS –1 . The MP number size distribution was dominated by MP < 100 μm and was well-described by a power law function. Assuming similar removal efficiencies for TSS and MP during the activated sludge process in combination with the MP concentrations in the activated sludge and the TSS contents in WWTP effluents allowed us to assess the loads of MP released by WWTP to surface waters. The loads across Switzerland were estimated to be 3.1 × 10 13 MP yr –1 corresponding to 4.7 t MP yr –1, resulting in per capita emissions of 5.2 × 10 6 MP (capita yr) −1 corresponding to 0.5 g MP (capita yr) −1 .