Decay of Free Residual Chlorine in Wells Water of Northern Brazil

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.

Automated summary

This study evaluated the decay kinetics of free chlorine in alternative individual water supply solutions used in Porto Velho in the Brazilian Amazon region. The type of well and initial chlorine concentration significantly influenced the decay speed of free chlorine, with water samples from tubular wells having lower chlorine demand levels attributed to better water quality. Simulation of residual chlorine decay in different water sources is an important tool for supporting safe disinfection processes.