Review on the occurrence and fate of microplastics in Sewage Treatment Plants

Georgia Gatidou; Olga S Arvaniti; Athanasios S Stasinakis

doi:10.1016/j.jhazmat.2018.12.081

Review on the occurrence and fate of microplastics in Sewage Treatment Plants

J Hazard Mater. 2019 Apr 5:367:504-512. doi: 10.1016/j.jhazmat.2018.12.081. Epub 2018 Dec 29.

Authors

Georgia Gatidou¹, Olga S Arvaniti², Athanasios S Stasinakis³

Affiliations

¹ Department of Environment, University of the Aegean, 81100, Mytilene, Greece. Electronic address: ggatid@env.aegean.gr.
² Department of Food Technology, Ionian University, 28100, Argostoli, Greece.
³ Department of Environment, University of the Aegean, 81100, Mytilene, Greece.

PMID: 30620926
DOI: 10.1016/j.jhazmat.2018.12.081

Abstract

Microplastics are plastic fragments lower than 5 mm that are detected in the environment causing various effects on organisms. Several research articles have recognized Sewage Treatment Plants as important sources of polyethylene and polypropylene beads, polyester, polyamide and other types of microplastics. For their determination, techniques such as visual identification using microscope, Fourier-transform infrared and RAMAN spectroscopy are used, while chemical oxidation, enzymatic maceration and density separation are applied as pretreatment methods for the removal of the inorganic and organic content. Microplastics' concentrations range up to 3160 particles L^-1, 125 particles L^-1 and 170.9 × 10³ particles Kg^-1 TS dw in raw, treated wastewater and sludge, respectively. Their removal during wastewater treatment ranges between 72% and 99.4%; the main processes that contribute to their removal are primary and secondary treatment, while the effect of tertiary treatment depends on the applied technology. Entrapment in suspended solids and accumulation to sludge are the major mechanisms governing their fate. A standardized protocol for samples' collection and pretreatment as well as microplastics' isolation and characterization is needed; future reseach should investigate the possible chemical and physical changes of microplastics during treatment, and their role as carriers for the transfer of emerging micropollutants.

Keywords: Analysis; Biosolids; Microliter; Presence; Wastewater.