Avaliação da eficiência de sistemas de alagado construído cultivados com Typha angustifolia (Rota 1) e Crysopogon zizanioides (Rota 2) no tratamento de águas residuárias de bovinocultura de leite.

Abstract

The confined dairy cattle system aims to increase productivity by making it possible to increase the number of animals per area; however, it faces a major environmental problem with regard to waste disposal. The greater the number of animals confined, the greater are the volume of residues, which has been a major challenge for breeders and specialists, since it involves technical, sanitary and economic aspects. In this context, the objective of this study was to evaluate the efficiency of two routes of a pilot effluent treatment system in the treatment of dairy cattle wastewater. One route used a constructed wetland planted with taboa (Typha angustifolia) while the second route used a constructed wetland planted with vetiver (Chrysopogon zizanioides). The steps common to both routes are: dung, septic tank, biological filter of upward flow and biological filter of downward flow. From there, the effluent divided and followed to the two wetlands studied. The efficiency of the system was evaluated from the following parameters: nitrite, nitrate, phosphorus, ammonia, pH, total suspended solids (TSS), turbidity, color, electrical conductivity (EC) and hydrogenation potential (pH). The septic tank obtained a statistically significant removal of the parameters: total suspended solids (48%), turbidity (68.7%) and color (54.9%). Biological filters indicated statistically significant mean removal rates in the following parameters: total suspended solids (21.9%) and turbidity (7.9%). The total flooded system (18.3%), color (8.7%) and turbidity (12.4%) were found to have significant individual removal rates. The wetland constructed with vetiver (route 2) presented significant individual removal rates: total suspended solids (17.8%), color (8.2%) and turbidity (12%). The great efficiency of the system in the removal of the physical parameters of the effluent is a very important point when it is intended to use the treated effluent in agricultural fertigation. The efficient reduction of this parameter decreases the propensity of clogging of the drippers and, therefore, a greater operational efficiency of the system.