Aplicação de tratamentos biológico e físico-químico em efluentes de lavanderia e tinturaria industriais do município de Toritama no estado de Pernambuco

Abstract

The industrial effluents with dyes are recalcitrant pollutants exhibiting toxicity to the living being and are difficult to remove by conventional processes. The treatment process of jeans uses large volumes of water and various chemicals, including synthetic dyes. This study investigated the influence of biological and physico-chemical factors in the removal of color and turbidity in the effluent treatment from laundry and dyeing industries. Factorial designs with central point were used in biodegradation and coagulation-flocculation treatments using analysis of interactions between the investigated factors. The independent variables were microbial consortium, aeration, agitation, tannin and the floculation polymer (POLICAP - 32) concentrations, whereas the response variables were color and turbidity. The microbial consortium with capacity of dye decolorization was obtained from the effluent in the absence of nutrients at 28 to 30 ° C, aeration of 1 vvm under agitation of 150 rpm. The biological treatment of the effluent occurred during 48 hours. In the experimental design of the biodegradation, the aeration and the increase of the agitation unfavored significantly the decolorization. The higher removal of color was obtained from the central point of the factorial design 1.25 % v/v consortium concentration and 50 rpm agitation. In this condition, the color average reached approximately 138 mgPt/L, corresponding to a decolorization of the untreated effluent of approximately 90 %. In the physico-chemical treatment, the increase of the tannin concentration and the interactions between tannin and polymer concentrations significantly favored the decolorization of the effluent. The higher removal of color and further reduction of turbidity were obtained at the central point of the factorial design 0.3 g/mL tannin concentration, 15 ppm polymer floculation at pH 7.5 for 20 minutes. In this experimental condition, the average color was approximately 50 mgPt/L and the average turbidity, approximately 4 NTU. The decolorization reached 96 % and the turbidity reduction, 79 % of the untreated effluent in the physical-chemical treatment