Avaliação de desempenho de lagoas de estabilização por meio de dados de monitoramento e modelagem em Fluidodinâmica Computacional (CFD)

• Ano de defesa: 2012
• Autor(a) principal: Ricardo Gomes Passos
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Meio Ambiente e Recursos Hídricos; Saneamento; Engenharia sanitária
• Link de acesso: http://hdl.handle.net/1843/BUBD-92RJ35

The Wastewater Treatment Plant serving the Tancredo Neves International Airport, in Confins MG consists of a facultative pond followed by a maturation pond. In an attempt to obtain a diagnosis of the system operation, its performance was assessed through: the monitoring of physical, chemical, microbiological and hydrobiological parameters (1994- 2010); a previous characterization of the effluent at the airport; a bathymetric survey of the ponds and the construction of contour surfaces; hydrodynamic test field with dye and drogue; and CFD modeling (Computational Fluid Dynamics). In general, the monitoring results indicated that: the effluent of the airport is more diluted than domestic sewage, the units operated under-loaded most of the time and with HRTs higher than the minimum required; the facultative pond had satisfactory performance including nutrient and E. coli removal; thefinal effluent met the sewage discharge standards most of the time, except for pH and COD, besides the fact that a high concentration of algae might be present in the final effluent, accounting for the final values of COD/BOD/Solids. Low sludge accumulation rates were found. The bathymetric maps showed an uneven distribution between the two inputs of the facultative pond, a situation caused by the unequal distribution of the influent and greater accumulation near the input/output in both ponds. It was found that the winds considerably influence the flow in the superficial layer of the pond. Such effect was verified by observingoranges thrown on to the surface of the ponds as well as by the CFD modeling. The drogue, designed and built as part of this research, showed broadly satisfactory results. The recorded trajectories corresponded to those verified in the field and obtained by the CFD. The CFD modeling proved particularly useful in the evaluation of the hydrodynamic conditions of stabilization ponds, reinforcing a trend which is gaining space with recent research, primarily international (there are a few references in Brazil). From the model, it was possible to verifythe occurrence of short circuiting, dead zones recirculation zones and vortex, dispersion of constituents and a closer estimate of the actual HRT of the ponds, by means of a virtual tracer test.