title: Do wastewater treatment plants act as a potential point source of microplastics? Preliminary study in the coastal Gulf of Finland, Baltic Sea.
abstract: This study on the removal of microplastics during different wastewater treatment unit processes was carried out at Viikinmäki wastewater treatment plant (WWTP). The amount of microplastics in the influent was high, but it decreased significantly during the treatment process. The major part of the fibres were removed already in primary sedimentation whereas synthetic particles settled mostly in secondary sedimentation. Biological filtration further improved the removal. A proportion of the microplastic load also passed the treatment and was found in the effluent, entering the receiving water body. After the treatment process, an average of 4.9 (±1.4) fibres and 8.6 (±2.5) particles were found per litre of wastewater. The total textile fibre concentration in the samples collected from the surface waters in the Helsinki archipelago varied between 0.01 and 0.65 fibres per litre, while the synthetic particle concentration varied between 0.5 and 9.4 particles per litre. The average fibre concentration was 25 times higher and the particle concentration was three times higher in the effluent compared to the receiving body of water. This indicates that WWTPs may operate as a route for microplastics entering the sea.
authors.affiliation: Department of Civil and Environmental Engineering, Aalto University, PO Box 15200, FI-00076, AALTO, Finland E-mail: julia.talvitie@aalto.fi.
authors.forename: Julia
authors.initials: J
authors.lastname: Talvitie
authors.affiliation: Helsinki Region Environmental Services Authority HSY, PO Box 100, FI-00066 HSY, Finland.
authors.forename: Mari
authors.initials: M
authors.lastname: Heinonen
authors.affiliation: City of Helsinki Environment Centre, PO Box 500, FI-00099, Helsinki, Finland.
authors.forename: Jari-Pekka
authors.initials: JP
authors.lastname: Pääkkönen
authors.affiliation: City of Helsinki Environment Centre, PO Box 500, FI-00099, Helsinki, Finland.
authors.forename: Emil
authors.initials: E
authors.lastname: Vahtera
authors.affiliation: Department of Civil and Environmental Engineering, Aalto University, PO Box 15200, FI-00076, AALTO, Finland E-mail: julia.talvitie@aalto.fi.
authors.forename: Anna
authors.initials: A
authors.lastname: Mikola
authors.affiliation: Finnish Environment Institute, Marine Research Center, PO Box 140, FI-00251 Helsinki, Finland.
authors.forename: Outi
authors.initials: O
authors.lastname: Setälä
authors.affiliation: Department of Civil and Environmental Engineering, Aalto University, PO Box 15200, FI-00076, AALTO, Finland E-mail: julia.talvitie@aalto.fi.
authors.forename: Riku
authors.initials: R
authors.lastname: Vahala
mesh_terms: D005374:Filtration; D005387:Finland; D010969:Plastics / Q000032:analysis*; D014865:Waste Disposal, Fluid; D018505:Waste Management; D062065:Wastewater; D014867:Water; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014876:Water Pollution
chemical_list: D010969:Plastics; D062065:Wastewater; D014867:Water; D014874:Water Pollutants, Chemical