MCQOPTIONS
Saved Bookmarks
| 1. |
In sewage treatment, the detention period allowed for oxidation ponds ranges from __________ weeks. |
| A. | 1 to 2 |
| B. | 4 to 5 |
| C. | 9 to 10 |
| D. | 15 to 20 |
| Answer» C. 9 to 10 | |