TREATMENT OF DAIRY EFFLUENTS IN WETLANDS SYSTEMS WITH FLOATING AQUATIC MACROPHYTES

Abstract

The aim of this study was to evaluate the Eichhornia crassipes and Salvinia auriculata efficiency as bioremediation alternatives for wastewater from a dairy company in Toledo, Paraná. The experiment was performed between June and August of 2014, for 36 days in the greenhouse at PUCPR campus Toledo. It was used 750 liters of effluent from a dairy plant in Toledo-PR, arranged in three polyethylene reactors, operating intermittently (batch). The repetitions were performed according to the hydraulic retention time (HRT), every 4 days. It was evaluated 7 physicochemical parameters of the effluent (temperature, pH, turbidity, total solids, COD, total nitrogen and total phosphorus). The results obtained during the experiment were satisfactory, it was observed the maximum efficiency of turbidity, total nitrogen, and COD of 94.4%, 90.26% and 82%, respectively, with E. crassipes and 91.7%, 75.65% and 82% respectively for S. auriculata. However, from the period between the day 16 and the day 20 of the experiment, it was observed increases in the level of the parameters because some plants got into the senescent process, returning to the environment half of all that were absorbed. This result suggests the necessity of removal plants in senescence, so the system can work properly. The aquatic macrophyte E. crassipes was better biorremediator for dairy effluents than S. auriculata, however, both of them can be widely used in the treatment of wastewater with high levels of organic matter and nutrients.