Assessment of autochthonous aquatic macrophytes with phytoremediation potential for dairy wastewater treatment in floating constructed wetlands.

The phytoremediation potential of autochthonous aquatic plants has been increasingly explored. This study investigated the use of macrophytes found in natural ecosystems in the southern coast of the state of Bahia, Brazil, for treatment of dairy wastewater (DWW) using experimental systems of the floating constructed wetland type. Four species of aquatic macrophytes have been tested using floating platforms made from PET bottles. The chemical oxygen demand (COD), biochemical oxygen demand (BOD), total solids (TS), pH, and temperature of DWW were analyzed for 15 days. On the fifth day, a 74.8% (±7.7) decrease of BOD was achieved. (86.4%) and (84.8%) showed the best results, while and achieved the removal of 65% and 74.2% of BOD, respectively. Considering the TS reduction in the DWW diluted with rainwater, the best results were obtained by (64.3%) and (65.18%). The macrophytes of the genus showed a greater potential for the treatment of DWW than the macrophytes and , with a hydraulic retention time varying between four and five days.