What are the major design considerations for secondary clari

What are the major design considerations for secondary clarifers following activated sludge processes?

Major design considerations for sctivsted sludge process:

1) Hydraulic retention time

2) Organic loading rate

3) specific food/ substrate utilization rate

4)sludge age

5) F/M Ratio

6) Recirculation ratio

7) Sludge volume index

These seven are the major desing consideration