In this paper an evaluation is made of the performance of "wetlands" systems used for post treatment of the effluent from a UASB reactor. The removal of organic material, forms of nitrogen and phosphorus were evaluated. The UASB reactor treats municipal sewage in the City of Campina Grande-Brazil. The produced effluent was pumped to four pilot scale "wetlands" units. Three of these were cultivated with emerging macrophytes (Juncus sp) whereas the fourth was operated without vegetation as a control unit. The three units with vegetation were operated with different hydraulic loads: 4.5, 3.3 and 2.3 cm d-1. The results obtained during the operation period of twenty six weeks were promising. The observed removal efficiencies of organic matter (measured as COD) ranged from 76 to 84% for application load varying from 6.58 to 14.2 g COD m² d-1. With respect to nutrient removal, it is shown that it was possible to produce an effluent with 6.1 mg L-1 N-NH+4 L-1 and 7.6 mg L-1 of TKN with about 86 and 87% removal, respectively, whereas the removal of phosphorus was observed to be 100% in the "wetlands" system operating with a hydraulic load of 2.3 cm d-1.
constructed "wetlands"; post treatment; nutrient removal macrophytes
