Ontario Operator-in-Training (OIT) Practice Exam

Which chemical is NOT commonly used for water disinfection in Ontario?

1. Chlorine gas

2. Sodium hypochlorite

3. Calcium hypochlorite

4. Potassium sulfate

The correct answer is: Potassium sulfate

Potassium sulfate is not commonly used for water disinfection in Ontario due to its primary function as a fertilizer and its limited antimicrobial properties. In the context of water treatment, chlorine gas, sodium hypochlorite, and calcium hypochlorite are all well-established disinfectants. These chemicals effectively eliminate pathogens and are widely used in municipal water treatment systems to ensure the safety of drinking water. Chlorine gas is a traditional and widely used method for disinfection due to its ability to kill bacteria and viruses. Sodium hypochlorite is commonly found in household bleach and is also utilized in various water treatment processes. Calcium hypochlorite, often used in tablet form, is another effective disinfectant that is favored for its stability and effectiveness in killing pathogens. Therefore, among the listed chemicals, potassium sulfate stands out as not being a disinfectant used in the water treatment process in Ontario.