Modeling and calibration of residual chlorine in Epanet software. Case study: Town of Villa de Leyva (Boyacá, Colombia)

Abstract

The supply of the aqueduct service integrates an essential factor to access a basic level of quality of life and so avoid the transmission of pathogenic diseases in the population. Within the purification of water resources, the physicochemical process “disinfection” is developed in the treatment plants, where the applied concentration is implemented by the trial method without taking into account the behavior of the disinfectant in the aqueduct networks. Therefore, in the following research developed in the town of Villa de Leyva (department of Boyacá, Colombia) in 2019, the behavior of free residual chlorine in the pipes of the supply network is explained, through the modeling and calibration of 3 stages in the Epanet software, according to the variation of the reaction coefficients (KWall), (KBulk) and the roughness-wall reaction correlation coefficient (F). Carrying out the hydraulic and quality calibration process, in stage n°. 1, a percentage of error between the read and computed values of 11 % for the pressures and 0.3% for the chlorine levels was obtained, according to the coefficients (KWall) y (KBulk) de -0.65 y (F) -2.88 that model the supply network. Having calibrated the first stage, the coefficients obtained were used to start the modeling of the second and third stages. For the case study, it was observed that the behavior of free residual chlorine varies according to the pressures during the day, in the peak consumption intervals the pressures decrease and the levels of the disinfectant increase, due to the fact that the flow is transported with greater rate through the pipes generating less reaction of the chemical agent.