GPS-X Technical Reference

181 Suspended Growth Models
Pond Models in Other Libraries
The above methods for determining the values of state variables from the empirical pond
models are for CNLIB only. These methods have been extended to the other libraries by
making small additions and changes based on the new and/or different state variables.
Table 6-6 describes these differences.
Table 6-6 - Library-specific Algorithms for Empiric Pond Model
Library
CNIPLIB
Additions/Changes from CNLIB pond methodology
All particulate IP components (xza to xzo) settle similarly to xi (not changed
biologically, but undergo settling and mixing, as appropriate). Soluble IP
components (sza to szo) are unaffected by biological activity, but undergo
mixing.
CNPLIB
slf and sf behave similarly to ss. PAOs are transformed similarly to xbh and
xba. sp is not modelled, and is treated the same as si.
CNPIPLIB
slf and sf behave similarly to ss. PAOs are transformed similarly to xbh and
xba. sp is not modelled, and is treated the same as si. All particulate IP
components (xza to xzo) settle similarly to xi (not changed biologically, but
undergo settling and mixing, as appropriate). Soluble IP components (sza to
szo) are unaffected by biological activity, but undergo mixing.
OXIDATION DITCH
Setting the Recycle Flow
The oxidation ditch object operation as 16 CSTRs in series (a plug flow tank) with a large
recycle from the last tank to the first. The recycle can be specified in four different ways
from the Operational menu, using the ditch recirculation mode setting, shown in
Figure 6-21.
GPS-X Technical Reference