Evaluation of the effect of temperature changes on chlorine mass deterioration in the water supply network using EPANET (II) qualitative-hydraulic simulation system

Environmental and health organizations believe that water entering the water distribution network should always have a certain amount of free chlorine remaining (at least 0.6 mg/L according to standard 1053). The founding philosophy of this standard is based more on the possibility of re-contamination in the water network. Experience in the operation of urban water distribution networks shows that various factors can lead to microbial growth and contamination in treated water. These parameters include the presence of biofilms in parts of pipes, the entry of external contaminants (microorganisms active in the soil) due to the phenomenon of leakage, the entry of air pollution in open tanks and the transfer of pathogens intentionally or Unintentionally pointed out. However, factors such as the reaction of chlorine with the wall of the distribution system pipe or the reaction with the matrix of materials in the water lead to a decrease in the concentration of free chlorine remaining throughout the network. Meanwhile, chlorine mass decay is a function of the materials in the water and the water temperature in the network. Therefore, this study intends to evaluate the effect of temperature changes on the residual chlorine concentration of the network using qualitative-hydraulic modeling and simulations. Studies have shown that in different time series, the remaining free chlorine changes up to 32% in different months of the year.