This work aimed to evaluate the potential of phytoremediation using Pistia stratiotes as a plant for post-treatment of wastewater from domestic sewage. The experiment was conducted at Toledo-PR, Brazil, for 42 days, in a pilot scale model. In order to evaluate the efficiency of Pistia as a post-treatment of domestic sewage, parameters such temperature, pH, turbidity, total solids, COD, Ntotal and Ptotal contents were determined in the effluent, as well as the total contents of K, Ca, Mg, Cu, Zn, Fe, Mn, Cd, and Pb. The bioaccumulation of K, Ca, Mg, Cu, Zn, Fe, Mn, Cd, and Pb in the living tissues of P. stratiotes have also been detected. The results demonstrate efficiency removal of turbidity, Ntotal, Ptotal and COD of 98.5, 100, 100, and 79.18%, respectively. The effluent contents of nutrients and toxic metals fluctuated during the study. This can have occurred due to photosynthetic activities of microorganisms and the plant senescence. The evaluation of some parameters in the effluent, such as temperature, DO, and organic matter, influenced these facts. Low levels of DO were observed, in function to the physical barrier of macrophytes in water surface, preventing the entry of air and light. The use of P. stratiotes proved to be a good complement for post-treatment of wastewater from domestic sewage.
Keywords: Aquatic plants; bioaccumulation of metals; bioremediation; removal of pollutants; wastewater treatment.