Otimização do tratamento da água residuária proveniente da lavagem de PET para reciclagem

Abstract

The generation of waste in the productions processes is part of the daily life of the companies. These residues, when liquids, are known as effluents and should be treated for later reuse or release into the environment. Based on this concept, M&G Fibras Brasil, located in Poços de Caldas - MG, treats wastewater from PET recycling process following the steps of railing, equalization, coagulation, flocculation and geotextile - technology for separation solid-liquid. In order to optimize the current process, this work aims to evaluate the implementation of primary decanter followed by draining block, through a pilot system and then characterize the statistical analysis of linear correlation and ANOVA. Thus, after the railing step, it was installed the decanter followed by the block, and it was analyzed in the raw, clarified and filtered effluent samples, the following parameters: COD, pH, sedimentable solids, total solids, total volatile solids, dissolved oxygen (OD) and alkalinity. Furthermore, it was analyzed the moisture content and total volatile solids of the sludge retained in the block. It was verified the necessity of implantation of the primary decanter, due to the fact that 7.4 ± 6,6% of the organic matter (COD) and 79.6 ± 16,9% of the sedimentable solids were removed in the clarified current. However, the draining block was not efficient in drying the sludge retained for a period of 24 hours, with moisture content around 82.9 ± 4,5% and total fixed solids concentration of 90.0 ± 3,5%, and a subsequent treatment was necessary to remove the sludge moisture. According to the statistical method ANOVA, by the p-value, the COD variation was observed according to the lots inserted in the process, while the other variables, such as pH, SS, OD and SFT do not vary significantly with the change of the type of recycled bottle. Also, by the linear correlation, the values ​​of the Pearson coefficient were shown to be intense in the linear relation SFT vs moisture of the sludge and removal SS clarified vs removal SS filtered of the effluent.