Primary Clarifiers (Primary Settling Tanks)
Next, the sewage is directed to one of four primary clarifiers (primary settling tanks). The primary clarifiers remove the larger suspended solids and floating material from the degritted wastewater prior to discharge to the aeration tanks.
This significantly reduces the load on the aerators and increases efficiency. The clarifiers can effectively remove 50% - 60% of the suspended solids and 25% - 40% of the BOD5
from the wastewater.