What effect does organic matter have on chlorine disinfection?

Organic matter plays a significant role in the chlorine disinfection process by increasing chlorine demand. When chlorine is added to water, it not only works to disinfect pathogens but also reacts with organic material present in the water. This reaction can consume a portion of the chlorine, effectively reducing the amount available for disinfection. As a result, more chlorine must be added to achieve the desired levels of disinfection, which is why the presence of organic matter is associated with increased chlorine demand.

Chlorine reacts with organic compounds to form chlorinated organic byproducts, which can not only decrease the free chlorine levels needed to inactivate pathogens but can also lead to the formation of undesirable substances like trihalomethanes (THMs). Therefore, managing organic matter concentrations in water is critical for optimizing the effectiveness of chlorine-based disinfection processes.