Santos, Guarujá and Praia Grande 1 submarine outfalls: computational evaluation of the effluent dispersion process in the Santos Bay using CFD

摘要

The usage of preliminary wastewater treatment plants and subsequent ocean disposal via submarine outfalls for domestic sewage is a design choice which has been implanted in S?o Paulo state coast, particularly in the south region named Baixada Santista. A physical model was constructed in the Hydraulic Laboratory of Polytechnic School at the University of S?o Paulo – Brazil, representing Santos estuary – Baixada Santista and three of these submarine outfalls: Guarujá, Santos and Praia Grande 1. The study required preliminary computer simulations followed by tests in the physical model using an advanced methodology for the plume monitoring. In this paper some computer simulations results will be presented using integral computer method and CFD, to evaluate the effluent dispersion process in the Santos bay from the operation of Santos, Guarujá and Praia Grande 1 outfalls. Results will be presented considering the operation of these three outfalls simultaneously or of the Santos outfall alone. The simulations were done for transient discharge considering the tidal variation data in the two entrance of the bay: access channel to Santos Harbor and Mar Pequeno channel. Wind effect in the effluent dispersion process was also simulated. The results of computer simulations in terms of the concentration field of the effluent parameters were confronted with the values established by Brazilian Environmental Legislation, through CONAMA [1].