Transport and fate of microplastics in wastewater treatment plants: implications to environmental health

Global studies of microplastic (MP) pollution confirm wastewater treatment plants serve as pathways for microplastics entering terrestrial and aquatic ecosystems. The behaviour, transport and fate of microplastics in wastewater effluents remain mostly unknown, rendering wastewater-derived microplastics as a contaminant of significant concern. We critically examine the literature to understand the sources and fate of microplastics in wastewater treatment plants (WWTPs) and the implications of treated effluents admitted to soil and aquatic systems. The transport of chemical and biological contaminants is also discussed in detail, using fundamental principles of vector relationships. For the removal and reduction of microplastics, profound knowledge is required from source to solution. This review presents a comprehensive overview of the significance of microplastics as a vector of water-borne contaminants in WWTPs.