Estudo da lixiviação do lodo da estação de tratamento de água do município de Caçapava do Sul - RS

Abstract

The growth of large urban centers with the installation of industries and homes without proper planning led to the disposal of effluents in the water bodies and made the water unfit for consumption. Thus the solution found in the ETAs was the increase of the concentration of chemical reagents so that the water reached the levels of quality for consumption and other purposes. Within this treatment, especially in the process of decanting and filtering the water, a residue is generated which is known as sludge, which is withdrawn from the treatment plant by washing the decanter and filter. Because it is a residue with complex treatment, it does not have a correct and clear final disposition for the companies that generate it that consequently discard it in an inadequate way as the discharge in the bodies of water, in the soil in any way or a more viable option , however expensive when it involves transportation resources that is discarded in landfills. In Caçapava do Sul, the disposal of this sludge is done on land owned by the treatment unit itself after passing through the drying bed, because there is no environmentally adequate destination for final disposal. The sludge generated in the ETA after washing the filters and decanters is conducted by gravity to the drying unit and in the sequence to the final disposal ground. From this, this work has the objective of analyzing the data of the invalid disposal process, which is a recurrent leaching within the scope of a process and diagnosis that is being established in the area. For this purpose, leach columns with characteristics that are in loco and water analysis after percolation of the leachate in containers placed under the samples will be used. Quantification of aluminum, calcium and iron will be done which are the reagents frequently used in the treatment. With turbidity analysis, biological oxygen demand (BOD) and chemical oxygen demand (COD), pH, total solids and apparent color. The results showed that there is no contamination in the leachate water from the sludge, because the analysis parameters are equivalent to the values established for surface and groundwater, allowing the continuation of the drainage system to the drying bed present at the sludge storage.