Modelagem ambiental de autodepuração do Rio Madeira utilizando o modelo Streeter-Phelps

Abstract

In the State of Amazonas, Brazil, only 22% of the population has wastewater collection in their homes and 19% have wastewater treatment, which is below the national average. One of the main problems facing Brazilian bodies of water is the pollution generated mainly by the discharge of efuents above their autodepuration capacity. In Brazil, the National Council for the Environment establishes standards for the discharge of efuents into bodies of water, as well as their classifcation. Therefore, in this work, environmental modeling in a computational environment through the Scilab software will be used, taking as reference the Biochemical Oxygen Demand (BOD) and Dissolved Oxygen (DO) parameters to study the autodepuration capacity of the Madeira River. All work was carried out through bibliographical research and computer simulations, using the Streeter-Phelps mathematical autodepuration model. The results were compared with current environmental laws to discuss whether they are ideal or can/should be changed. The Streeter-Phelps model proved to be adequate for the study. The Madeira River proved to have a high autodepuration capacity. Even the highest release of 1000 mg/L at a flow rate of 1 m³/s managed to be cleared by Madeira in less than 600 km. In the average flow, in 4 days there was the return of the body of water to the clean water zone. In critical flow, this time was approximately 8 days. Through the evaluation of the simulations according to the release standards, it was concluded that the environmental government agencies can make the release of efuents in the Madeira River more flexible, as the releases did not affect the OD and BOD values beyond the established limits.