WQA Academy

Chlorination of drinking water has been a key factor in the dramatic reduction of waterborne disease in the United States. Secondary disinfection in the form of maintaining a chlorine residual within the distribution system is very important. The chlorine residual can take several forms with have different disinfection (oxidation) potentials, decay rates and byproduct formation. Chlorine residuals vary from point to point within the distribution system as a result of chlorine decay. This occurs for a number of reasons and water system operators must monitor their system and take a proactive approach to maintaining an adequate residual without over-chlorinating, or over-flushing.

This class will identify and anaylize the following:

• The effectiveness of free chlorine residuals
• Explanation of the four reaction zones,
• Formation and types of combined chlorine residuals
• Nomenclature for Chlorine Residual
• Formation of chloramines and the three stages of reaction
• Beyond breakpoint, the causes of chlorine residual decay. 
• Distribution flushing requirements