PERFORMANCE OF CONSTRUCTED WETLANDS SYSTEMS IN POLLUTANTS REMOVAL OF DAIRY INDUSTRY WASTEWATER

The objective for this research was evaluate the efficiency of constructed wetlands systems (CWS), cultivated with two different grasses and five organic loading rates (OLRs), in the removal of pollutants from dairy industry wastewater (DIW). For this, experimental units were formed by a CWS without vegetation (CWS-SV), with five CWS cultivated elephant grass (CWS-EG) and five cultivated with Tifton 85 grass (CWS-TG), with horizontal subsurface flow. The DW has been applied in average flow of 60 L day(-1) and hydraulic residence time of 4.8 days and average surface organic loading rates (OLR) of 66, 130, 190, 320 and 570 kg ha(-1) day(-1) of BOD. The CWS were efficient in removal BOD5, COD, TSS, TS and TKN, but were inefficient in P-total, K and Na removal of the DIW. The two evaluated grass had similar influence in the BOD5, COD, TS, TSS, total-P, K and Na removal, when compared with systems that operated with the same OLR and the removal of BOD5 and COD were in range 79-96 % and 85-97 %. The CWS-SV performance was similar to the cultivated CWS in the removal of BOD5, COD, TS, TSS and Na, but while the cultivated with tifton was more efficient in removing TKN.