MCQOPTIONS
Saved Bookmarks
| 1. |
The duration of contact of chlorine with water before it is served to the first consumer, shouldbe at least |
| A. | 10 to 15 minutes |
| B. | 15 to 20 minutes |
| C. | 20 to 30 minutes |
| D. | 30 to 40 minutes |
| Answer» D. 30 to 40 minutes | |