Where would you typically find the lowest concentration of chlorine residual in a water distribution system?

Where would you typically find the lowest concentration of chlorine residual in a water distribution system?

• A. At the point of application
• B. The farthest location from the point of application
• C. Chlorine residual concentration remains the same, from the point of application to the farthest location
• D. 200 ft downstream from the point of application

Answer: (B)

In a water distribution system, the lowest concentration of chlorine residual is typically found at the farthest location from the point of application. This phenomenon occurs due to several factors that lead to the decay of chlorine residual as water travels through the distribution system. As chlorine is added to the water, it begins to react with organic materials, sediments, and other constituents present in the water. Over time, these reactions consume chlorine, reducing its concentration. Additionally, the chlorine can be lost due to dilution effects as water moves through the system, especially in older or longer pipelines where the potential for reaction and dilution increases. Thus, as you move away from the point where chlorine is applied, its concentration decreases due to these factors. In contrast, at the point of application, chlorine has just been introduced, therefore it is at its highest concentration. The notion that chlorine residual concentration remains the same throughout the distribution system does not account for these interactions and reactions that occur along the pipeline. Lastly, while a point 200 ft downstream from the application might have a lower concentration than the point of application, it is not necessarily the lowest concentration compared to much farther locations where the chlorine has had more time and distance to decompose and react. Thus, it stands to reason that the

In a water distribution system, the lowest concentration of chlorine residual is typically found at the farthest location from the point of application. This phenomenon occurs due to several factors that lead to the decay of chlorine residual as water travels through the distribution system.

As chlorine is added to the water, it begins to react with organic materials, sediments, and other constituents present in the water. Over time, these reactions consume chlorine, reducing its concentration. Additionally, the chlorine can be lost due to dilution effects as water moves through the system, especially in older or longer pipelines where the potential for reaction and dilution increases. Thus, as you move away from the point where chlorine is applied, its concentration decreases due to these factors.

In contrast, at the point of application, chlorine has just been introduced, therefore it is at its highest concentration. The notion that chlorine residual concentration remains the same throughout the distribution system does not account for these interactions and reactions that occur along the pipeline. Lastly, while a point 200 ft downstream from the application might have a lower concentration than the point of application, it is not necessarily the lowest concentration compared to much farther locations where the chlorine has had more time and distance to decompose and react. Thus, it stands to reason that the