1. Chlorination & Chlorine Demand

2. Chlorine Demand Chlorine gets used up when disinfecting water
The total amount of chlorine that must be added to the water to disinfect it is its chlorine demand.
Would good water have a high or a low chlorine demand?
The United States Environmental Protection Agency’s maximum residual disinfectant level goal for chlorine is 4 ppm.

3. The lab tests:
Read through the lab sheet and complete the required tests.
Record your results in the boxes on the right of the lab sheet.
What was your chlorine reading from the first lab?
If more than 4 mg/L, could there be a problem with our water?

4. Our results:
How are the results of these tests important to the water treatment process?
How did the chlorine demand from the tea bag affect the chlorine concentration of your water sample?
How might tap water be affected if it were exposed to a similar chlorine demand before or during the water treatment process or in the distribution system?