Per- and polyfluorinated alkyl substances, PFAS, have emerged as contaminants of global concern due to their extensive industrial use, environmental persistence, mobility, and potential adverse effects on ecosystems and human health. The LIFE-CASCADE project aims to develop innovative analytical methods and wastewater treatment technologies to improve the detection and removal of these emerging contaminants from textile industry effluents. Within this framework, a mesocosm experiment was conducted using artificial ditch systems to investigate PFAS dynamics, bioavailability, and ecological effects associated with wastewater discharged from the Bulgarograsso WWTP (Como, Italy). Mesocosms represent a more realistic way to evaluate community dynamics than single species tests. Five stainless steel canals were established and supplied with different water sources: one received background water as a control, while the others were fed with WWTP outflowing water before and after ozonation. Chemical and biological analysis were conducted before treatments (T-1), after 1 hour from the treatments (T0), after 1 day (T1, acute effect evaluation), and after 15 and 30 days (T15 and T30, chronic effect evaluation). The experiment was designed to evaluate the suitability of the mesocosms, verify the effectiveness of macroinvertebrate colonization, and identify the temporal scale at which potential PFAS-related (or other chemical) effects on aquatic communities could be detected. Chemical analyses revealed that PFPeA and PFHxA were the dominant compounds across treatments. An increase in short-chain PFAS concentrations was observed between T0 and T1, suggesting the possible transformation of precursor compounds. Similar concentration patterns detected in both ozonated and non-ozonated treatments indicate a limited effectiveness of ozonation in reducing PFAS loads under the tested conditions. Preliminary analyses of macroinvertebrate communities showed a decrease of 25 % of macroinvertebrates collected at T1 versus control, and about 30% at T15, with a prevalence of Chironomidae among the individuals, while full diversity and abundance analyses are ongoing.