Performance of the constructed wetland systems in pollutants removal from hog wastewater

Abstract

The main objective of this work was to evaluate the efficiency of a constructed wetland systems (CWS) for pollutants removal, in mono crop and multi crop with three different species of plants, originated from hog wastewater treatment (HW). Therefore, 5 CWS of 24.0 m x 1.1 m x 0.7 m were constructed, sealed with a membrane of polyvinyl chloride (PVC) and filled with 0.4 m of small gravel. In CWS1, CWS2 and CWS3 grown to cattail (Typha latifolia L.), Alternanthera philoxeroides (Mart.) Griseb. and Tifton 85 grass (Cynodon dactylon Pers.), respectively. In the bed of CWS4 was planted at 1st third Alternanthera, cattail, in the 2nd third and tifton-85 grass and in the 3rd third of. The CWS5 was not planted and it was used as control. After passing through a filter filled with crushed bagasse of sugar cane, the HW was applied to the CWS in a flow of 0.8 m3 d-1, which corresponded to a hydraulic detention time of 4.8 days. According to the results it was shown that the five CWS(s) had statistically nearly the same removal of pollutants, and the average removal efficiency of TSS, COD, BOD and Zn, were 91, 89, 86 and 94%, respectively. Also high removals were obtained concerning the ST, N-total, NH4+ and P-total, with average values of 62, 59, 52 and 50%, respectively. The plants in all planted CWS worked in a similar way maintaining the system efficiency and the non cultivated CWS presented analogous capacity of pollutants removal when compared to the cultivated CWS(s).