Which of these chemicals should be used for odor control in sewers?

• A. Chlorine
• B. Muriatic acid
• C. Potassium chloride
• D. Sodium chloride

Answer: (A)

Odor control in sewers is achieved by using oxidizing agents that react with sulfur-containing odorous compounds, primarily hydrogen sulfide produced by bacteria in the wastewater. Chlorine serves this purpose well because it oxidizes sulfides, turning them into less odorous substances like sulfates, which lowers the smell and also provides a little disinfection as a bonus. In contrast, muriatic acid is a strong acid used for cleaning or pH adjustments and isn’t effective for odor control in sewers; it can be dangerous and may cause corrosion. Potassium chloride and sodium chloride are simply salts and don’t react with sulfur compounds to reduce odors, so they aren’t used for this purpose.