Occurrence, Characteristics, and Removal of Microplastics in Wastewater Treatment Plants

This chapter presents a summary of the occurrence, characteristics, and removal of microplastics (MPs) in sewage treatment plants, considered sinks and sources of MPs to the neighbouring environment. It intends to highlight the importance of these systems in transporting MPs to the aquatic and terrestrial surrounding environment, previously studying the removal rates and the best available technologies described for their elimination. Despite being a barrier, wastewater treatment plants (WWTPs) have proved to be an important source of MPs in the environment, both from treated effluent and the application of sludges in agricultural soils. Through 142literature data, the chapter discusses the abundance of MPs, the main methodologies for their identification and quantification, as well as the main polymers. It also discusses the removal rates for primary, secondary, and tertiary stages within the WWTPs, and the main technologies and operational parameters for their retention. Future perspectives regarding improvement in sewage treatment plants and research projects associated with them are also included; despite the high removal efficiencies achieved by the current treatment plants, the treated effluents still discharge millions of MPs into the receiving environment every single day.