Water Treatment Operator-in-Training (OIT) Practice Test

The method of disinfection that is known to produce trihalomethanes is chlorine gas. When chlorine reacts with organic matter present in water, it can lead to the formation of trihalomethanes (THMs), which are a group of chemical compounds that may have health implications if found in high concentrations. Ultraviolet light, while effective for disinfection, does not result in the formation of THMs because it does not involve a chemical reaction with chlorine. Ozone treatment is another disinfection method that is effective in killing microorganisms but does not produce THMs because it does not react with organic matter in the same way chlorine does. Chlorine dioxide is a different disinfectant that can also lead to the formation of some byproducts, but not THMs specifically. Understanding the chemistry involved in disinfection processes helps clarify how different methods can produce varying byproducts, emphasizing the importance of selecting the right method based on the water source and desired outcomes.