Aplicação de oxidação com ozônio seguida de adsorção em carvão ativado como pós tratamento físico-químico para reuso de efluente de indústria de café

Abstract

The significant water consumption in the soluble coffee industry, coupled with the complexity of its effluent, necessitates sustainable solutions for water treatment and reuse. This study aimed to evaluate the technical feasibility of a combined treatment system, employing ozone oxidation followed by activated carbon adsorption, as a post-treatment for reusing this effluent in cooling towers. The methodology involved the physico-chemical characterization of the raw effluent and samples after each treatment stage, focusing on parameters such as pH, alkalinity, calcium, iron, and total dissolved solids. The process efficiency was quantified by calculating and interpreting the Langelier Saturation Index (LSI) and Ryznar Stability Index (RSI), supplemented by an immersion corrosion test for practical validation of the results. The results showed that the raw effluent exhibited strong corrosive characteristics. The ozonation step, while effective in oxidizing compounds, intensified the water's acidity. However, the subsequent treatment with activated carbon was crucial, neutralizing the pH, restoring alkalinity, and reducing the concentration of contaminants. This improvement was reflected in the stability indices, which evolved from a highly corrosive condition to a state near chemical equilibrium. Notably, the final quality of the reuse water proved to be superior to that of the softened water currently used in the system, which has a higher corrosive potential. It was concluded that the integrated system of ozone and activated carbon is an effective strategy and represents a technical and environmental optimization, producing water of suitable and safe quality for reuse in cooling towers, thereby promoting a circular economy and sustainability in the industrial sector.