TRATAMENTO DE ÁGUAS CINZAS PELO PROCESSO COAGULAÇÃO/DECANTAÇÃO/FILTRAÇÃO/ADSORÇÃO

Abstract

The objective of this work was to present the gray water treatment through the coagulation / decantation / filtration / adsorption process using commercial activated carbon. The samples were collected in a residential laundry. The treatment used in this research was divided into two stages: (a) Coagulation / Flocculation / Decantation Process and (b) Effluent filtration in sand and Adsorption in activated carbon. The coagulation tests were performed in the Jar Test apparatus, being used as an aluminum sulfate coagulant. The fast and slow mixing speeds were 160 and 30 rpm, respectively. The fast and slow mixing times were 5 minutes and 30 minutes, respectively. The sedimentation time was 1 hour. The treatment system consisted of cylinders filled with sand and commercial activated carbon, operated in continuous flow, with the following dimensions: total height of the pipe 40 cm, height of the coal in the column 11 cm, diameter of the pipe 2.0 cm. The system was operated at a flow rate of 10 mL / min. The dosage of coagulant used of 200 mg / L provided a turbidity removal equal to 79%, which led to the use of the effluent treated with this dosage in the subsequent sand and activated carbon filtration tests. The parameters that obtained the highest percentage of removal in the proposed system were: turbidity, volatile solids, COD and residual chlorine with 99, 97, 92 and 89% respectively. The final effluent studied here was classified as class 3, and can be used to reuse toilet flushes, according to NBR13969 / 1997.