Desenvolvimento de um modelo via MEF para análise da dispersão de poluentes em rios, lagos e estuários

Abstract

Freshwater of good quality is a pre-requisite for social and economic development of a given region. Paradoxically, this same development is normally responsible for the pollution of their water sources, through domestic or industrial waste dumping without treatment, or through agricultural activities. In this way, the monitoring and the management of that sources are extremely important for the wellbeing of the people living in that region. Among the possible tools to auxiliary this management is the computational simulation of pollutant transport in the hydro medium. In this context, this work presents a computational procedure for the solution of the 2D advectiondiffusion- reaction equation, which is the basis for all the mass transport models. This process consists in the union of the finite elements and finite difference methods in the discretization of the spatial and temporal components, respectively. This methodology was evaluated with the help of tests with synthetic and real data. First one considered the case of mass transport by pure advection to ensure its stability in cases where the classical formulations fail. Second test simulated the transport of a hypothetical pollutant in a piece of a river and showed the correct effect of the drag due to advection and spreading due to diffusion. The last test evaluated the transport of total phosphorus in Agua Preta Lake from the pumped water of the Guama river and point sources located at the margins of the reservoir. The result of the simulation showed the potential of the algorithm to deal with cases closer to the reality.