Q. Cleaning period for a slow sand filter is taken as (Solved)
1. 1 hour to 3 hours
2. 1 day to 3 days
3. 1 week to 3 weeks
4. 1 month to 3 months
- d. 1 month to 3 months
1. 1 hour to 3 hours
2. 1 day to 3 days
3. 1 week to 3 weeks
4. 1 month to 3 months