Sistema de alerta ambiental fundamentado em estudo teórico- experimental de transporte e dispersão de poluentes solúveis em cursos d água

• Autor(a) principal: Ribeiro, Celso Bandeira de Melo
• Data de Publicação: 2007
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/626
• topic: Dispersão de poluentes; Traçador; Qualidade da água; Pollutants dispersion; Tracers; Water quality; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA::ENGENHARIA DE AGUA E SOLO::CONSERVACAO DE SOLO E AGUA

Information about capacity of transport and dispersion of soluble pollutants in natural streams are important in the management of water resources, especially in the planning of preventive measures to minimize the problems caused by accidental or intentional waste, in public health and economic activities that depend on the use of water. One of the most important parameters in one-dimensional water quality models is the longitudinal dispersion coefficient. The complexity and diversity of natural streams, prevent an purely theoretical approximation, so is necessary to determine "in situ" parameters that reflect the intrinsic characteristics of water bodies. Assessment with tracers are recognized as a proper mean to determining the longitudinal dispersion coefficient. They are considered reliable and precise to simulate the transport and dispersion of a solute, once they taking implicitly into consideration all features and hydrodynamic local characteristics of transport and dispersion. Thus, this study had the following objectives: a) determine the longitudinal dispersion coefficient in Pomba River using tracers techniques and fickian model; b) develop an equation for predicting the longitudinal dispersion coefficient bases on experimental results using fluorescent tracers techniques and compare the results with others obtained for existent models; c) develop alert system for contamination of river, to aim for to predict the effects of wastewaters throwing, on sections localized after wastewater throwing . Therefore, two tests were performed using two fluorescent dye tracers: Uranina (Acid Yellow 73, "Color Index" 45,350) and Amidorodamina G (Acid Red 52, "color index" 45220) to assess the transport and dispersion characteristics of soluble conservative pollutants in Pomba River, the reach evaluated stretched along 36 km from Astolfo Dutra and Cataguases Cities. The fickian Taylor s model, also known as the adjustment method was used to determine the longitudinal dispersion coefficient (DL), from the results obtained by tracers techniques. The equation for predicting the DL was deduced using dimensional analysis (Buckingham s theorem), and adjusted the data to the technical field of multiple linear regression. The system was carried out take into consideration the adjustment method (Taylor s model), the convolution and empirical formulas for foreseeing DL, time travel curve resulted from instantaneous or continuous injection downstream from the injection point. Results of two field experiments performed in Pomba River, showed fairly close, with values of DL and U, calculated by the Taylor model, ranging from 18,3 to 33,0 m2/s and 0,37 to 0.46 m/s, respectively. In developing the equation for predicting the DL, the adjustment of parameters obtained by the dimensional analysis and the results from experimental field data was measured by the determination coefficient (r2 = 0.85) and the 5% of significance. The equation developed in this study demonstrate more accurate in prediction of the DL, when compared to 12 other equations proposed in the literature, using the index of performance as a comparative method, where the best accuracy is the one that most closely approximates to 1. The proposal equation submitted accuracy equal to 0,60, while in other formulas considered in this study that value was below 0,27. The system has developed to be appropriate to evaluate the transport and dispersion of pollutants in natural streams from a instantaneous or continuous soluble pollutants injection.