Tratamento de efluente de laticínio por sistema alagado construído híbrido

Abstract

Concern over water resources is growing because of the importance of water quality for its various uses. Currently one of the main forms of degradation of water bodies is the discharge of effluents without proper treatment. Although it is of paramount importance to prevent pollution of water bodies treating industrials effluents. Dairy effluent is highly polluting, because they have high load of organic matter and nutrients. This work aimed to evaluate a hybrid constructed wetland system (CWS) consisted of a Horizontal subsurface flow (HSSF) wetlands (gravel zero and for the base and Cyperus papyrus “Nanus”) followed by a Vertical flow (VF) wetlands (medium sand as base and Heliconia psittacorum as plant). The collection of effluent was carried out in a dairy industry located in Londrina, PR, Brazil. The parameters analyzed were: chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), total phosphorus (TP), pH, apparent color, electrical conductivity, turbidity, solids grade and oils and greases. Were analyzed samples of the raw effluent, after HSSF and VF treatment .It was also evaluated the evapotranspiration for each species and subsequently compared to potential evapotranspiration of Thornthwaite. The hybrid CWS, compared to the activated sludge system of effluent treatment plant ETP, removed significantly more nutrients. The hybrid CWS was effective in removing organic matter and nutrients. The average removal of COD was 89%, NKT and TP 95 % removal, 74% of color apparent removal, 45% for turbidity and 13 % decrease of electrical conductivity. There was no statistically significant difference for the paramaters COD, NKT, TP, pH and total solids. Therefore, the VF CWS would not be necessary for the proposed treatment, as the contribution of HSSF CWS in removal is bigger. The importance of VF CWS is to reduce the variability of the final concentrations that justifies the use of a hybrid system.