Índice de qualidade da água e coeficientes de autodepuração de trechos do Rio Pomba

• Autor(a) principal: Almeida, Thomé Vidigal de
• Data de Publicação: 2006
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3662
• topic: Autodepuração; Índice de qualidade da água; Desoxigenação e reaeração; Self-purification; Index of water quality; Deoxygenation and reaeration; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA::ENGENHARIA DE AGUA E SOLO

With the condensation increase of the urban population and of the exploration of farming and industry in the region of Dove River, the pollutant charges were increased in the water route of the region. The contamination of the water by several resources, such as domestic emanation and industries and, the diffuse urban and farming charge in the Dove River, mainly in the passage in studying, that is, from the nascent (Santa Bárbara of Tugúrio district), passing through Mercês, up to the city of Dove River, has been target of preoccupation. To characterize the environmental conditions and the water qualities, in this work was determined the water quality Index (WQI) and it was quantified the coefficients of deoxygenation (K1) and the reaeration (K2), in this passage of the river. The samples of water to determine the WQI were colected the amount of the sanitarium exhaustion points of the mentioned cities, this index has been calculated using the method adapted by Miner Institute of Water Management (IGAM). The variable selected to the calculation of WQI were tolerant-fire coliform, pH, variation of temperature between the point of mixture and the one point the amount of the point of the mixture, turbidity, total solids, biochemistry oxygen demand (BOD), nitrate, phosphate e melted oxygen. The samples of water to determine the values of K1 e K2 were collected the ebb tide from the points of the cities sanitary exhaustion. The values of K1 were obtained using the method of quantification of the oxygen consume in samples kept to 20°C, with posterior adjust of the mathematics equation to the data of BOD discharged in function of the time. The values of K2 were obtained replacing the data (water temperature, local altitude, concentration of oxygen melted in the point of the mixture, BOD5d-20oC, water velocity, value of K1, traveled distance and the concentration of melted oxygen (MO) in the final of the passage) in the equation of Streeter-Phelps. Estimate equations of values of K2, as function of the velocity and the water depth in the river, they were adjusted for each passage of the studied river. The WQI obtained to the dry period were classified as good , medium and bad , respectively to the passages, nascent up to Santa Bárbara of Tugúrio, from this to Mercês and then to the city of Dove River. In the rainy period, the index was classified as good , medium e bad , to the same passages. The variables that interfered more to the decrease of the QWI value and that damage the classification of the water, according to Resolution # 357/2005 of the CONAMA, were counting of tolerant-fire coliform and turbidity. The obtained values of K1 were from 0,13 to 0,24 d-1 and the values of K2 from 0,40 to 1,90 d-1. The profile of melted oxygen concentration (MO) during the route indicated that, even in the more critical point, the concentration of MO was bigger than the established in the resolution # 357/2005 of the CONAMA, for course of water class 2. In the rainy period, there were carrying of soil and organic waste, increasing the turbidity and the counting of tolerant-fire coliform, worsen the waters quality. The coefficient K1 was low, in all the passages, denoting that the organic material present in these waters is of low biodegradability. The coefficient of reaeration (K2) was bigger in the route of bigger turbulence and environment of mountainous relief, that is, closer to the headboard of the Dove River.