The present paper was carried out to study the influence of organic loading rate (OLR) on the performance of subsurface flow constructed wetlands systems (CWs). Each CW was composed of a sealed tank of 0.40 x 0.73 x 3.00 m. The dairy industry wastewater was applied with flow rate of 60 L.d-1. In the control system, consisting of CW without vegetation, 130 kg.ha-1 d-1 of BOD was applied. In vegetated CWs (cultivated with elephant grass and tifton 85 bermudagrass), OLRs of 66, 130, 190, 320 and 570 kg.ha-1 d-1 of BOD were applied . The CW systems were efficient in the removal of BOD, COD, TSS, TS and nitrogen. OLRs between 250 and 400 kg.ha-1 d-1 BOD provide greater efficiencies in organic loading removal and above 400 kg.ha-1 d-1 in the solids removal from wastewater. The presence of the plants in the CWs showed to be important in the removal of N, K and Na of wastewater.
organic residues; root zones; phytoremediation
