Aplicação da reação de Fenton no tratamento de lodo de estação de tratamento de água

Abstract

The water treatment stations – WTP transform raw water into potable water and this process generates a WTP sludge residue, composed of organic matter, metals, solids and other pollutants. This residue is generally released into watercourses without any treatment, which can cause environmental damage to the water environment and to the watershed itself used to collect raw water. The management of these ETAs sludge requires economically viable alternatives for treatment. This study aimed to evaluate the addition of hydrogen peroxide - H2O2 in a sludge from a WTP that uses iron-based coagulant and thus promote ideal conditions for the Fenton reaction to occur and provide the reduction of organic matter and elimination of pathogenic microorganisms. Analyzes on the characteristics of the sludge were carried out and experimental conditions with the addition of H2O2 were established in neutral and acid medium to verify the best treatment proposal. Two sludge quantification methodologies were also compared using empirical formulas and mass balance. The results of the study indicated the removal of 58% of organic matter, under conditions with a H2O2 concentration of 33 mg/L at pH 3, with a clear separation of the liquid-solid phases and a reaction time of 30 minutes. For the inactivation of total coliforms and E. coli, the concentration of 3 mg/L of H2O2 at pH 3 and 21 mg/L at pH 7 were efficient. In this way, the WTP sludge that has iron has an alternative for its treatment and better possibilities for its reuse can be employed.