A sewage treatment process in which a part of decomposer bacteria present in the wastes is recycled into the starting of the process is called as
primary treatment
Activated sludge treatment
Tertiary treatment
None of these
As we have learnt,
Secondary treatment or Biological treatment -
activated sludge
- wherein
Once the BOD of sewage or wastewater is reduced significantly, the effluent is then passed into a settling tank where the bacterial ‘flocs’ are allowed to sediment. This sediment is called activated sludge