What is Bound Chlorine?
Bound chlorine, often referred to as combined chlorine, is a form of chlorine that has reacted chemically with nitrogenous compounds, including ammonia and organic nitrogen compounds found in water. This reaction results in the formation of chloramines or other chlorine-nitrogen compounds. Unlike free chlorine, which is available to oxidize and disinfect water by killing bacteria and other pathogens, bound chlorine has already reacted with contaminants in the water and thus has reduced disinfection capability. The significance of measuring bound chlorine lies in its indication of water quality; high levels can suggest the presence of organic material or ammonia, which can reduce the effectiveness of chlorine as a disinfectant. Bound chlorine is part of the total chlorine measurement, which is the sum of both free and combined chlorine levels in the water, providing a comprehensive overview of the chlorine’s status and effectiveness in water treatment processes.
Bound Chlorine in Water Treatment
In the realm of water treatment, bound chlorine emerges as a critical component, particularly in the context of disinfection. This form of chlorine results from the interaction between chlorine and nitrogenous compounds present in the water, leading to the formation of chloramines. These chloramines, or combined chlorine, serve as a disinfectant, albeit with a reduced efficacy compared to free chlorine. The preparation of chloramines for disinfection purposes involves the direct reaction of chlorine with ammonia or ammonia salts, a process conducted on-site to ensure effectiveness. The use of sodium hypochlorite stands out as the most prevalent method for chlorination in industrial waters, highlighting its significance in maintaining water quality and safety. Moreover, chlorine residual testing aims to optimise the dosage of sodium hypochlorite to maintain adequate levels of free chlorine in drinking water, underscoring the importance of balancing chlorine forms for effective disinfection. Overall, the strategic application of bound chlorine through chlorination processes underscores its indispensable role in the comprehensive treatment and disinfection of water, safeguarding public health against pathogenic organisms.
