Understanding the fate of nano-plastics in wastewater treatment plants and their removal using membrane processes

Nanoplastics (NPs) have become a major environmental issue due to their adverse effect on the water environment. Wastewater treatment plant (WWTP) is considered as one of the main sources for breaking down of larger-sized plastic debris and microplastics (MPs) into NPs. This study aims to provide a comprehensive understanding of NPs generation in the WWTPs, their physiochemical characteristics and interaction with the WWTPs. It is found that cracking is the major mechanism of plastics fragmentation in the WWTPs. This review also discusses the current membrane process used for NPs removal. It is found that conventional membrane processes are ineffective as they are not designed for NPs removal and fouling is a major obstacle for its application. Therefore, this study concludes by providing an outlook of developing a bio-nanofiltration process that can be used as a tertiary treatment for removing NPs and other components present in water. Such a process can produce NPs-free water for non-potable use or safe discharge into open waterways.

Automated summary

Nanoplastics have become a significant environmental concern due to their adverse effects on water environments. Wastewater treatment plants are identified as major sources of nanoparticle generation, primarily through the mechanism of cracking larger plastic debris. Current membrane processes are ineffective for nanoparticle removal, leading to the need for developing a bio-nanofiltration process as an alternative method. This process can produce nanoparticle-free water for safe discharge.