Which chemical may be used for odor control in sewers?

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

Answer: (C)

Odor in sewers is mainly caused by hydrogen sulfide produced by anaerobic bacteria. To tame those odors, a chemical oxidant is often used to convert the odor-causing compounds into less smelly, non-volatile products. Chlorine does this effectively, reacting with hydrogen sulfide to form oxidized compounds such as sulfates, which reduces the rotten-egg smell and also adds disinfection.

Muriatic acid is a strong acid used for pH adjustment and corrosion control, not for odor reduction, and it can create hazardous fumes. Sodium chloride and potassium chloride are simply salts and do not neutralize or remove odors. So chlorine is the best choice for odor control in sewer systems.