Bioremediation of Microplastics in Wastewater Treatment Plants: A Sustainable Approach

Microplastics (MPs) are emerging contaminants of growing concern in wastewater treatment plants (WWTPs), which serve as both critical sinks and inadvertent sources of these persistent pollutants. This chapter explores the potential of bioremediation as a sustainable strategy for MP removal, critically examining microbial and enzymatic degradation pathways across different stages of WWTPs. It synthesizes current knowledge on bacteria, fungi, algae, and higher eukaryotes capable of MP degradation while emphasizing their relevance within the operational context of biological treatment, tertiary polishing, and sludge stabilization units. Key strategies such as bioaugmentation, biostimulation, and enzyme-assisted treatment are evaluated with case studies and conceptual models, highlighting integration challenges related to retention time, biodegradation efficiency, and ecological compatibility. Advanced configurations like enzymatic membrane reactors and hyperthermophilic composting are presented as promising yet underexplored solutions. The chapter concludes with a critical reflection on the limitations of current bioremediation efforts, advocating for pilot-scale testing, microbial consortia engineering, and techno-economic assessments to enable scalable application in WWTPs. This comprehensive synthesis provides both foundational insights and forward-looking perspectives on deploying biotechnology for MP mitigation in engineered wastewater systems.