GPS-X Technical Reference

Suspended Growth Models 212
The ΔH term includes the following terms :
1. Convective and evaporative loss at the surface of the reactor due to aeration.
(H i)
2. Heat loss due to conduction across the reactor wall (H tw)
3. Heat input due to mechanical and blower energy (H p)
4. Heat input due to biological heat production (H b)
The calculation method for each heat transfer term is shown in Table 6-7. The present
model neglects the heat transfer due to solar radiation and long wave radiation. The
surface convection and evaporation losses are lumped into the convection and
evaporative heat transfer due to aeration.
Table 6-7 – Heat Transfer Terms with Equations for Estimation
H i
Heat Transfer Term
H tw = H tlaw + H tlsw
H p
H b = H baer+ H bdn+ H baut
Equation Used for
Estimation
U i.A.(T a-T wo)
H tlaw =U laA la(T wo-T a)
H tlsw =U lsA ls(T wo-T s)
P aer
H baer = H uaer*r OU
H bdn = H udn*r DN
H baut = H unr*r aut
Comment
Convective and evaporative
loss during aeration
Heat transfer liquid/air
contact wall
Heat transfer liquid/soil
contact wall
Power input of surface
aerator or blower
Heat generation from the
aerobic oxidation
Heat generation from
denitrification
Heat generation from
nitrification
The list of parameters used in the temperature estimation model is shown in Table 6-8.
GPS-X Technical Reference