Modelagem da degradação de cloro residual livre em sistemas de adubação de água de abastecimento de porte médio.

Abstract

The water supply in sufficient quantity and quality is essential to reduce the occurrence of waterborne diseases. The quality of water supplied in the supply system is provided by the disinfection treatment step responsible for the elimination of pathogenic microorganisms. The most commonly used disinfecting agent in the treatment stations is chlorine, as it has a number of advantages, including maintaining a residual water that protects against contamination throughout the distribution system. The concentration limit of the residual that must be satisfied at all points of the network, currently is regulated by the ordinance MS 2914/11. This is a major challenge for the utilities that due to the distance of the points and the ignorance of the behavior of chlorine in the system, practice super chlorination, action that may pose a health risk to consumers. Accordingly, many operators use of tools that simulate the behavior of chlorine in the system using the kinetic parameters that represent chlorine consumption in the distribution system. The objective of this study is the determination and calibration of these parameters, which will be used in modeling the water quality of treated water pipeline system of Campina Grande- PB. The determination of the kinetic coefficients of the reaction mass (kb) was made by the laboratory procedure called the test bottle and the reaction with the wall (kw) estimated by trial and error. The calibration of the model used the quality EPANET 2.0, which is a free simulator developed by the EPA. It was observed the predominance of reaction coefficients in the volume of flow, and a strong relationship of changes in operational behavior of the system with consumption of chlorine. The results showed that absence of a defined procedure for determining the kinetic coefficients gives rise to uncertainty in the model, necessitating development of a more appropriate system changes.