Wastewater Treatment Approaches to Remove Microplastics

Abstract

The main way that microplastics (MPs) enter into the environment is through sewage systems. Every day, wastewater treatment plants (WWTPs) receive millions of microplastics, especially fibres, which mainly come from household washing machines and also from the textile industry. Although WWTPs are not specifically designed for the removal of MPs from wastewater, elimination efficiencies higher than 90% can be achieved in these facilities. This incomplete removal during the treatment processes of wastewater still leads to the discharge of a large number of MPs, fibres being the most predominant particle, into water masses. Additionally, microplastics removed from wastewater are mostly entrained in sludge, which can be managed in different ways. Frequently, sewage sludge is employed as organic fertilizer, becoming a source of MPs pollution in soils. Hence, WWTPs are a major contributor to the release of microplastics into the environment. Concern about this environmental problem in the European Union has been increasing in recent years, and the European Parliament submitted a proposal (TA/2019/0071) to address MPs pollution in treated wastewater and sludge. In this chapter, an overview of different available technologies that can be employed at lab scale and/or at treatment plant scale for the removal and/or recovery of MPs, especially fibres, from wastewater is provided.