Question

The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about:

• A. 0.05 to 0.5 ppm
• B. 0.5 to 1.0 ppm
• C. 1.0 to 5.0 ppm
• D. 0.01 to 0.05 ppm

Answer 1

Answer:

A. 0.05 to 0.5 ppm