Decaimento da concentração de cloro residual livre nas redes de abastecimento de água

• Autor(a) principal: Oliveira, Luciano de
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/8787
• topic: Decaimento de cloro; Redes de abastecimento de água; Tempo de residência; Chlorine decay; Water supply networks; Residence time; ENGENHARIA SANITARIA::SANEAMENTO AMBIENTAL

The chlorination process is the most used to promote disinfection of water intended for human consumption. During the course of chlorinated water in the supply systems, the concentration of free residual chlorine (FRC), whose reaction rate depends on the characteristics of the natural water, occurs. In this work, we studied the decay of the FRC concentration related to the reactions in the liquid mass in two types of water, of subterranean and superficial origin, with different concentrations of organic matter, with the perspective of the influence of the water travel time, dependent on consumption scenarios in real distribution networks, whose supply modules are characterized by low population density and that operate under the initial demand conditions predicted in the projects. The effect of temperature and total organic carbon on the values of mass decay kinetic constants (k b ), used in mathematical models that simulate water quality, was considered. The results showed that the variation of the kb values is directly proportional to the water temperature and the TOC. For initial concentrations close to 1.00 mg.L -1 , the values of the kinetic constants for waters from surface water sources maintained in the temperature ranges of 20 to 21 °C and 30 to 31 °C were respectively 0.0888 day -1 and 0.1200 day -1 for samples collected at the ETA filter output of the DAIAsystem and TOC value of 0.4798 mg.L -1 and equal to and 0.1680 day -1 and 0.3024 day -1 for the samples collected at the filter outputs of the Piancó and TOC system ETA of 0.8750 mg.L - . In samples of groundwater with TOC of 0.1740 mg.L -1 , maintained at the same temperature 1 ranges, the kinetic coefficients were 0.0264 day -1 and 0.0480 day -1 , respectively. Experiments for temperature between 30 and 31 °C and near test duration showed a significant difference in chlorine decay behavior in filtered water samples collected at conventional treatment plants, which showed a residual chlorine loss percentage of 64.81% in relation to the initial concentration of 1.08 mg.L -1 of disinfectant (ETA DAIA) and 33.65% in relation to the initial concentration of 1.05 mg.L -1 of disinfectant (ETA Piancó). Raw water samples from the underground spring lost 14.33% of the initial concentration of 1.04 mg.L -1 . The travel times for the most critical nodes and the minimum disinfectant concentrations at the entrance of the supply modules to comply with the legislation were 40 hours and 0.27-0.28 mg.L -1 for the distribution networks of the condominium Valley of the Birds and 144 hours and 0.30-0.36 mg.L -1 for the condominium Terras Alphaville.