Identificação de microplástico na estação de tratamento de esgoto em uma instituição de ensino superior

Abstract

The extensive use of plastic worldwide, in its different shapes, colors, sizes, and densities, generates waste, which is weathered to dimensions of less than 5 mm, forming the so-called microplastics (MP). These contaminants can be found in effluents from wastewater treatment plants and in various foods present in the human diet, such as honey, sugar, salt, beer, wine, soft drinks, milk, etc. Currently, contamination by MPs is a challenge for science and public environmental management. It is estimated that around 12 billion tons of plastic waste will be released into the environment by 2050. Thus, this study aimed to verify the presence and identify MPs in the grid residues retained in the preliminary treatment (raw affluent and effluents from the aerated biological filters (FBAS) of the Sewage Treatment Station (ETE) of the University Federal de Lavras (UFLA). The method used to extract the MP from the grid residue was the digestion of the organic matter of the sample using hydrogen peroxide (H2O2) and subsequent flotation of the material in a saline aqueous medium (NaCl). The microplastic in the raw and outgoing effluents was detected using the direct filtration method to retain the particles on qualitative filter paper with a grammage of 180 grams, removing the turbidity from the solution and subsequently clarifying the suspension material, allowing better identification of the precipitate using a magnifying glass. Filaments, fragments, fibers, and shapeless MP particles were identified in the grid waste (primary sludge). Filaments and MP fragments were identified in the raw affluent and in the effluent from the aerated biological filters. The analysis results indicated the presence of polyethylene (PE).