Evaluation of Microplastic Abundance and Removal in Wastewater Treatment Plant Processes

Wastewater treatment plants (WWTPs) are potential microplastic (MP) sources for receiving ecosystems (aquatic/terrestrial). MPs reach WWTPs from different sources. Although these plants are not designed to remove MPs, varying rates of MP removal occur in primary, secondary, and tertiary treatment stages. Despite high MP removal efficiencies, MP pollution exists for receiving environments, when large volumes of wastewater discharge are considered. In addition, the reuse of sewage sludge as fertilizer and the MPs retained in the sludge cause pollution of terrestrial ecosystems. High removal efficiencies can be achieved with advanced treatment technology such as combined systems and electro-coagulation, where the degree of purification is important for the effective removal of MPs. In this study, the fate of MPs in WWTPs and their removal efficiencies depending on the applied technologies were compared, MP sources, formation, and disposal (wastewater/sludge) coming to WWTPs were examined, and MP removal mechanisms related to treatment processes were evaluated.