The objective of this study was obtain the coefficients of organic matter removal in constructed wetlands (CWs) cultivated with different plant species, in tropical climatic conditions, when used in swine wastewater treatment. In tanks of 24.0 m x 1.1 m x 0.7 m, sealed with PVC canvas, filled with a layer (0.4 m of depth) of fine gravel were planted cattail (CW1), alligator weed (CW2) and tifton 85 bermudagrass (CW3). In CW4, was planted, on the 1st third, alligator weed; on the 2nd third, cattail and in the last third, tifton 85 bermudagrass. The swine wastewater, previously treated by organic filters made of bagasse from sugar cane, was applied at rate of 0.8 m³ d-1in CWs, which corresponded to a hydraulic retention time (HRT) of 6.4 days, approximately. Wastewater samples were collected in sections 0 (entry), 4; 8; 12; 16; 20 and 24 m (output) of each CW. In the samples collected were analyzed the concentrations of COD and the obtained values were used to adjust apparent kinetic parameters. There was no difference (p>0.05) among the CWs, in respect the COD removal, however the year season influenced the dynamics of organic matter removal in CWs performance. The values of the parameter k v' were, during the summer, between 0.94 and 1.52 d-1. During the autumn/winter season, the k v' coefficient showed lower values, between 0.88 and 1.07 d-1.
swine wastewater; root zones; removal kinetics; phytoremediation
