What is the daily maximum chlorine limit value in mg/L?

• A. 0.009 mg/L
• B. 0.029 mg/L
• C. 0.019 mg/L
• D. 0.039 mg/L

Answer: (C)

Chlorine residual in the effluent is tightly controlled because it can affect aquatic life and compliance with discharge permits. The daily maximum value represents the highest concentration measured in any 24-hour period, and that value sets the limit you must not exceed for that day. In this context, the official daily maximum allowable residual chlorine is 0.019 mg/L. This small threshold means operators must monitor and, if needed, adjust dosing or use dechlorination to ensure the daily peak does not surpass 0.019 mg/L. The other numbers would not meet the permit requirement, so they aren’t acceptable as the daily maximum.