Eletrofloculação aplicada no tratamento de efluente lácteo: delineamento experimental e otimização de múltiplas respostas

Abstract

One of the main concerns of society is the preservation of water resources. Industries that use high volumes of water in processing, such as the dairy industry, generate a large amount of effluent. It is necessary to develop treatment techniques that associate low cost with high efficiency. The process of electroflocculation (EF) appears as an alternative to the processes of treatment of effluents. The objective of this research is to apply EF technology, using Al as a sacrifice electrode, in the treatment of the effluent of the dairy industry, evaluating the efficiency in the removal of color, turbidity, chemical oxygen demand (COD) and absorbance λ - 254 nm, besides defining the optimal treatment conditions. The DCCR 2³, composed of 17 trials, was used as the experimental design. Analysis of variance (ANOVA), surface contour, contour and overall desirability graphs served as a basis for determination of optimized treatment conditions. These results demonstrated with 95% confidence the significance of the independent variables to obtain the removal of the response variables. The optimized conditions determined by statistical analysis are initial pH of 4.5, current 3.34 A and treatment time 55.2 min. The removals obtained under these conditions were 72,95 % COD, 95,8 % turbidity, 97,9 % apparent color and 71,5% absorbance λ-254 nm. The EF treatment technique proved to be efficient for the removal of the response variables, although other parameters analyzed did not present high efficiency.