Modelagem da degradação de cloro residual livre na rede de distribuição de água da cidade de Campina Grande-PB.

Abstract

The sanitary quality of the water is assured in the disinfection step of the treatment process. In Brazil Ordinance 2.914/2011 of the Ministry of Health, which regulates the procedures for controlling and monitoring water quality for human consumption and its potability water standard, recommends a minimum free chlorine residual of 0,2mgCl2/L, maximum of 2,0mgCl2/L and the maximum permitted value of 5,0mgCl2/L that must be ensured in the distribution network. Due to factors such as age of pipes, leaks, material, diameter and long distances between treatment systems and consumption centers, the recommended concentrations of free residual chlorine are not always maintained at all points in the water distribution network. This study aims to model the decay of free residual chlorine in the distribution network of the city of Campina Grande, Paraiba, by determining the residual chlorine concentration degradation kinetic free coefficients in the flow volume (kb) by the bottle test and in the wall of the pipes (kw) by the trial and error method. As a modeling tool was used EPANET 2.0. The study area of this research was the distribution network of the district of Prata, located in zone of pressure B. This local was chosen for presenting a diversified network, PVC pipes and asbestos cement being its distribution network supplied by the reservoir R5. With the results was concluded that the decay of the free residual chlorine in the distribution network of the district of Prata occurs by reactions in the volume of the flow, the values of kb are high in the sections of the network and the degradation more intense concentration of free chlorine residual occurs due to stagnation of water in the pipes.