Decay of Free Residual Chlorine in Wells Water of Northern Brazil

Abstract

The concentration of chlorine in water declines as it reacts with various substances, causing decay of the residual free chlorine until its total consumption. In light of the typical characteristics of the water from protected dug wells and tube wells, this study aimed to evaluate the decay kinetics of free chlorine in the water of alternative individual supply (AIS) solutions used in the city of Porto Velho in the Brazilian Amazon region. The free chlorine decay constant in the water was evaluated by “bottle tests,” applying a first-order model. According to the results, the type of well and initial chlorine concentration significantly influences the free chlorine decay speed. The water samples from the tubular wells had lower chlorine demand levels, attributed to their better water quality. The simulation of the residual chlorine decay in the different supply sources is an important tool to support safe disinfection processes.

Assessment of bacterial communities and residual chlorine dynamics within underground and overhead water storage tanks

“…The amount of residual chlorine may decrease despite the addition of a 1 mg/L dose by university's concerned authorities (Javed et al, 2022). This reduction in concentration is justi ed based on rationale that considerable concentration of added chlorine is consumed by the oxidation of organic and inorganic compounds present in water (Vargas et al, 2021), thereby leading to more bio lm formation. Moreover, studies have revealed the impact of different residual chlorine contents on bio lm characteristics, such as composition, structure, microbiome, and water quality.…”

Development of a Point-of-Use Drinking Water Purifier Using Aluminum Oxide-Based Flocculent-Disinfectant Composite

“…The residual chlorine concentration was in the range of 0.09 to 1.72 mg/L. Residual chlorine is defined as the concentration of chlorine species present in water after the oxidant demand has been met [28]. The report from the Centers for Disease Control and Prevention indicates that the presence of residual chlorine in drinking water indirectly implies the absence of diseasecausing organisms, secondly, it indicates that the water is protected against recontamination during transportation and storage at home [29].…”

Influence of physical and water quality parameters on residual chlorine decay in water distribution network

“…Physical water parameters are pipe length [ 2 , 7 ], pipe diameter [ [7] , [8] , [9] ], pipe roughness [ 2 , 9 ], pipe age [ 2 , 9 ] and pipe material [ 10 ]. Water quality parameters include initial chlorine concentration [ 2 , 7 , 9 , [11] , [12] , [13] , [14] , [15] , [16] ], pH [ 4 , 7 , 12 , 15 , [17] , [18] , [19] , [20] , [21] , [22] ] and turbidity [ 2 , 4 , 7 , [11] , [12] , [13] , [14] , [15] , [16] , [18] , [19] , [20] , [21] , [22] ]. However, turbidity which is commonly used by water utilities as an indicator proxy surrogate for initial chlorine dosage for suspended and colloidal organic and inorganic impurities in water [ 16 , 21 ].…”

“…The effect is continuous loss of residual chlorine as treated water is conveyed from treatment plant downstream to consumption points. Other water quality parameters are electrical conductivity [ 7 , 15 , 17 , 18 , 20 , 22 , 23 ] which together with other water quality parameters excluding turbidity account for about 75 % variability in free chlorine decay [ 16 ]. This statistic demonstrates the significance of electrical conductivity in free chlorine residual decay in water distribution.…”

“…However, it is suggested that concentrations of inorganics less than 0.3 mg/l have insignificant effect on residual chlorine decay [ 24 ]. Temperature is another key water quality parameter that influences residual chlorine decay [ 2 , 4 , 8 , 9 , 12 , 13 , 15 , 16 , [18] , [19] , [20] , 25 , 26 ]. Temperature varies spatially and temporally with residual chlorine decay in water distribution networks [ 23 ].…”