Q. After cleaning the slow sand filter, the filtered water should not be used for a period of (Solved)
1. upto 6 hours
2. 6 hours to 12 hours
3. 12 hours to 24 hours
4. 24 hours to 48 hours
- d. 24 hours to 48 hours
1. upto 6 hours
2. 6 hours to 12 hours
3. 12 hours to 24 hours
4. 24 hours to 48 hours