The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about
A. 0.01 to 0.05 ppm
B. 0.05 to 0.5 ppm
C. 0.5 to 1.0 ppm
D. 1.0 to 5.0 ppm
Answer:B
The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about
A. 0.01 to 0.05 ppm B. 0.05 to 0.5 ppm C. 0.5 to 1.0 ppm D. 1.0 to 5.0 ppm