Activated sludge in municipal wastewater treatment plant serves as a potentially source of microplastics: Source...

The discharge of Municipal wastewater treatment plant (WWTP) is one of the important ways for microplastics (MPs) to enter the natural environment. Therefore, this study conducted in depth research on a combined sewer treatment plant, exploring the occurrence characteristics, migration mechanisms, and correlation with climate factors of MPs in activated sludge(AS), and conducting traceability analysis of MPs in AS. Research has shown that the main forms of MPs in AS are small-sized fragments (0.25-0.50 mm) and large-sized fibers (1.00-5.00 mm), with polyester (PES) and polypropylene (PP) as the main components. The Positive Matrix Factorization (PMF) model was applied to analyze the four main sources of MPs, which are household sources (15.88 %), textile sources (48.7 %), agricultural sources (21.95 %), and industrial sources (13.47 %); The Absolute Principal Component Score-Multiple Linear Regression (APCS-MLR) model source analysis shows that the proportion of mixed sources of industrial, agricultural activities, and residential life is 62.71 %, and the proportion of textile activities is 28.31 %. Our research has validated the good applicability of PMF and APCS-MLR models for MPs source apportionment, which can provide important theoretical support and technical guidance for WWTP to analyze the main sources of MPs from different perspectives.