What chemical is commonly used for disinfecting small public water supplies?

Sodium hypochlorite is widely recognized for its effectiveness in disinfecting small public water supplies. This compound acts as a powerful oxidizing agent that can effectively kill bacteria, viruses, and other pathogens present in water. Its usage is particularly advantageous because it is easy to handle, readily available, and cost-effective, making it ideal for smaller systems that may not have extensive equipment for disinfection.

The ability of sodium hypochlorite to generate chlorine in solution when it is dissolved in water allows it to provide a continuous residual disinfectant that can help maintain water quality throughout the distribution system. Additionally, it is effective over a range of pH levels, which makes it versatile for various water types.

Other choices such as soda ash, copper sulfate, and fluoride do not serve the primary purpose of water disinfection. Soda ash is mainly used for pH adjustment and softening; copper sulfate is sometimes used to control algae and specific pests rather than as a general disinfectant; and fluoride is typically added to promote dental health and does not have disinfecting properties. Thus, sodium hypochlorite is the appropriate choice for effective disinfection in small public water supplies.