Navigating microplastics in wastewater treatment: Understanding analysis, mitigation, removal strategies, impact, and current knowledge gaps

Microplastics (MPs) pose a global threat to both the environment and human health. Wastewater treatment plants (WWTPs) have been identified as major contributors to MPs pollution in freshwater and coastal ecosystems. This review addresses the critical issue of MPs in WWTPs, focusing on their detection, removal processes, environmental impact, and the current gaps in knowledge. Reported concentrations range from 0.70 to 1567.49 n/L in influent wastewater and from 0.002 to 356 n/L in treated effluents, highlighting the effectiveness of WWTPs in reducing MPs. However, the lack of standardized protocols for sampling, pretreatment, and analysis remains a significant challenge for generating consistent and comparable data. This review not only examines MP removal techniques but also emphasizes the need for improved methods to ensure accurate identification and characterization. To address these gaps, we propose actionable recommendations based on the authors' experience. Future research should prioritize refining these methodologies to enhance our understanding of MP pollution and its mitigation. • WWTPs have been identified as significant sources of plastic pollution. • Sampling, treatment, removal, and characterisation methodologies have been reviewed. • Microplastics (MPs) detected in WWTP influents range from 0.70 to 1567.49 n/L. • Great amounts of MPs (0.002 – 356 n/L) are released daily into the environment. • WWTPs’ are efficient at removing MPs but further work must be done.