This study evaluates the removal of Polyethylene Terephthalate (PET) microplastics from synthetic greywater using four coagulation–filtration systems: GAC alone, FeCl₃+GAC, CPE+GAC, and FeCl₃+CPE+GAC. Among them, FeCl₃+GAC showed the highest removal efficiency for turbidity (97.5%), TOC (98.0%), COD (96.0%), and BOD₅ (94.0%). Although the dual coagulant system (FeCl₃+CPE) had comparable results, it did not outperform FeCl₃ alone. CPE alone achieved full PET retention, likely due to electrostatic and bridging interactions. Zeta potential shifts confirmed effective particle destabilization. Fluorescence microscopy verified PET removal. The treated effluent met FAO/WHO standards for restricted irrigation.