Briquettes from sludge in sewage treatment plant: calorific power

Abstract

Due to the large volume of sewage generated every day, there is a high demand for its treatment. The by-product (called sludge) generated after the treatment process has caused problems in terms of its final disposal. Since the typical end off for this waste is landfills, it is mandatory reducing the landfill amount and the risk of soil contamination. The present work explored an adequate final disposal of the sludge as a sustainable alternative. For this purpose, briquettes were produced using dry sludge from the Sewage Treatment Plant of the Minas Gerais (Brazil) Sanitation Company and vegetable oil used to thicken the briquettes. These briquettes were compared to eucalyptus charcoal in terms of their calorific potential, through immediate analysis, since Brazil has a high demand for primary energy, especially in the industrial sphere. The calorific potential of charcoal reached 16.66 MJ/kg, while that of briquette reached 12.94 MJ/kg. However, briquettes had a density much higher than charcoal, so it takes a smaller volume of briquettes to achieve the same burning capacity as a large volume of charcoal.