What is typically the first step in determining the chlorine demand of water?

The first step in determining the chlorine demand of water involves adding a chlorine dose. This process is essential because chlorine demand refers to the amount of chlorine that is consumed by substances in the water before reaching a residual level. By adding a predetermined dose of chlorine to the water, operators can identify how much of that chlorine is utilized by organic and inorganic materials present, as well as by any contaminants.

Once chlorine is added to the water, it can be measured before and after the addition to assess how much has been consumed, which directly informs the chlorine demand of the water. This critical information is necessary for designing effective disinfection processes and ensuring that sufficient chlorine residual remains for water treatment purposes.

Measuring pH, while important for understanding how chlorine behaves in water, is not the first step in measuring chlorine demand. Similarly, conducting a bacteria test or testing mineral content is more focused on assessing other aspects of water quality rather than directly measuring chlorine demand itself.