The usefulness of wolffia arrhiza for decontamination of waters from phthalates and other organic compounds was studied using artificial growing medium and real municipal wastewater samples. The eight most frequently detected phthalates were considered: dimethyl (DMP), diethyl (DEP), dipropyl (DnPP), dibutyl (DnBP), diisobutyl (DIBP), bis(2-ethylhexyl) (DEHP), diizoheptyl (DIHP) and diizononyl (DINP). The reduction of phthalates concentration observed during seven days of W. arrhiza cultivation on artificial growing medium was between 78.9 and 99.7%. Kinetics of phthalates degradation by W. arrhiza in real effluent wastewater was similar to those with laboratory-made solutions. The significant removal of nutrients (75-78%) and reduction of oxygen demand (93-97%) was achieved during cultivation of W. arrhiza. Purification efficiency of non-treated municipal wastewater with W. arrhiza was better than obtained with the use of Lemna minor, which is wide used in constructed wetlands, and not much worse than those obtained in conventional Wastewater Treatment Plant (WWTP). Analysis of biochemical components, stress markers and antioxidant activity in W. arrhiza shows its good acclimation to high pollution of aquatic environment. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.