Desempenho de sistemas alagados no tratamento de águas residuárias do processamento dos frutos do cafeeiro

Abstract

Nine constructed wetlands (SACESHs) were built on a pilot scale (1.5 m long, 0.5 wide and 0.4 m deep), grown with Typha sp. and Alternanthera phyloxeroides, and operated under different organic loads in the treatment of wastewater of coffee processing (ARC). Three systems received no ARC pre-treatment, three received ARC with correction of pH and nutritional correction, and the last three received the effluent of filters used in the anaerobic treatment of ARC that had the pH and nutrient content corrected. The results showed that the increase in the rate of surface charge of the constituents of the ARC provided the decrease in efficiency of removal of all SACESHs evaluated. The hydraulic detention time of more than 100 h provided higher efficiencies in the removal of COD (SAC* 1 , SACF 1 and SACF 2 ) and BOD (SAC1 , SAC* 1 , SACF 2 and SACF 3 ) than hydraulic detention times of approximately 60 h implemented in the early stages of the experiment. Among SACESHs the SACF 1 , which received the lowest organic load (1500 kg ha-1 d-1 of COD), showed a satisfactory performance with regard to the removal of BOD (63%), COD (85%) and phenolic compounds (65%).