In last 10 years, the interest about the presence of microplastics (MPs) in the environment has strongly grown. Wastewaters function as a carrier for MPs contamination from source to the aquatic environment, so the knowledge of the fate of this emerging contaminant in wastewater treatment plants (WWTPs) is a priority. This work aims to review the presence of MPs in the influent wastewater (WW) and the effectiveness of the treatments of conventional WWTPs. Moreover, the negative impacts of MPs on the management of the processes have been also discussed. The work also focuses on the possible approaches to tackle MPs contamination enhancing the effectiveness of the WWTPs. Based on literature results, despite WWTPs are not designed for MPs removal from WW, they can effectively remove the MPs (up to 99 % in some references). Nevertheless, they normally act as "hotspots" of MPs contamination considering the remaining concentration of MPs in WWTPs' effluents can be several orders of magnitude higher than receiving waters. Moreover, MPs removed from WW are concentrated in sewage sludge (potentially >65 % of MPs entering the WWTP) posing a concern in case of the potential reuse as a soil improver. This work aims to present a paradigm shift intending WWTPs as key barriers for environmental protection. Approaches for increasing effectiveness against MPs have been discussed in order to define the optimal point(s) of the WWTP in which these technologies should be located. The need of a future legislation about MPs in water and sludge is discussed.

Wastewater treatment plants (WWTPs) are increasingly recognised as critical control points for mitigating microplastic (MP) emissions, yet their potential role in polymer recovery remains largely unexplored. Among MPs, micro-polyethylene terephthalate (micro-PET), mainly derived from synthetic textile fibers, represents a valuable secondary raw material. This study investigated the fate, removal and recovery potential of MPs and micro-PET along anaerobic digestion, mechanical dewatering and tertiary pile cloth filtration of a full-scale WWTP. Pile cloth filtration proved effective as a refinement step in the water line, achieving an overall MP removal efficiency of 67 ± 12.6%. In the sludge line, anaerobic digestion did not significantly affect MP abundance, whereas mechanical dewatering removed 49.7 ± 32.3 % of MPs via the process water, acting as a barrier to MP release. The water streams identified as potential starting points for the proposed recovery process showed elevated MP concentrations, ranging from 6.86 ± 4.66 MP L^-1 in filter wash water to 56.5 ± 12.8 MP L^-1 in dewatering water. Micro-PET was detected in filter wash water, supporting the feasibility of the proposed recovery concept; however, its absence in dewatering water suggests that applicability may depend on the composition of the incoming wastewater and on process-specific factors. The optimized separation protocol showed robust and reproducible performance, enabling micro-PET enrichment from complex wastewater- and sludge-derived matrices despite high biomass loads and biofilm-coated particles. Overall, the results suggest that integrating microplastic mitigation with selective polymer recovery could represent a first step towards more resource-oriented wastewater management.