Computational numerical modeling for dispersion of pollutants in water bodies

The constant degradation of urban streams has been a cause of concern for the environment and human health. The objective of this work was to propose a model using the classic diffusion-advection equation to describe the dispersion of pollutants in a stretch of the Sao Raimundo basin in the urban area of Manaus. For the resolution of the Linear Partial Differential Equation, the methods of Centered Finite Differences were used together with the Crank-Nicolson method in Matlab@ environment. With the realization of the simulations, it was possible to observe the evolutionary movement of pollutant patches, a concentration near the source due to the contrary action of the wind in relation to the river current, and a decrease in the intensity of the pollutant after a while, influenced by the factors of decay due to evaporation, surface absorption or by species that feed on this pollution. The results were coherent with what happens in real situations, contributing to the search for mitigating measures for the problems of dispersion of pollutants in rivers.