Q. The rate of accumulation of sludge in septic tanks is recommended as (Solved)
1. 30 litres/person/year
2. 25 litres/person/year
3. 30 litres/person/month
4. 25 litres/person/month
- a. 30 litres/person/year
1. 30 litres/person/year
2. 25 litres/person/year
3. 30 litres/person/month
4. 25 litres/person/month