a alpha factor (–)
l dynamic viscosity (kg/m/s)
m kinematic viscosity (m2/s)
q density (kg/m3)
h temperature correction factor (–)
A/A/O anaerobic–anoxic–oxic
Ad total coverage area of the diffusers (m2)
At total area of the tank (m2)
AS(P) activated sludge (process)
Bt width of the tank (m)
CO2 concentration of dissolved oxygen (mgO2/l)
C_
O2 oxygen saturation concentration (mgO2/l)
D diffusion coefficient (m2/s)
db bubble diameter (m)
deq equivalent bubble diameter (m)
Dt tank diameter (m)
DO dissolved oxygen (mg/l)
Fr Froude number (–)
g acceleration due to gravity (=9.8 m/s2)
Ht height of tank (m)
hd diffuser submergence (m)
HRT hydraulic retention time (h)