GPS-X Technical Reference

Suspended Growth Models 130
The temperature dependence of the kinetic parameters is described by an Arrhenius equation. See
Appendix A for the Model matrix describing this model.
Aerobic denitrification is included in the model according to the Münch modification
(Münch et al., 1996). In many cases modellers have seen nitrate levels overpredicted in their
models due to the simplifications in spatial resolution (ideally mixed aeration tanks, no oxygen
diffusion limitation in floc cores, etc.). The new modification, consisting of one new anoxic
oxygen half-saturation coefficient makes anoxic growth rates adjustable independently from
aerobic growth, and the coefficient itself is an indication of the degree of aerobic denitrification
occurring within the plant modelled. The default value of the new constant is set equal to the
aerobic oxygen half saturation.
NEW GENERAL MODEL (NEWGENERAL)
Introduction
Dold's general model is not implemented in GPS-X, in favour of the newgeneral model.
However, a description of the general model (which makes up the basis for the
newgeneral model) is presented here.
In the following sections, the general model of Dold (1990) is described. This model was
derived from a combination of the asm1 model for non-polyP heterotrophic organisms
and autotrophic organisms (Henze et al., 1987a, 1987b) and the Wentzel et al. (1989b)
model for polyP organisms.
General Model Components (Non-PolyP Organisms)
The general model component proposed for describing the kinetic response of the
non-polyP heterotrophic and autotrophic organism masses is based on the asm1 model
(Henze et al., 1987a, 1987b), with three modifications/extensions:
1. The nitrogen source for cell synthesis
2. Conversion of soluble readily biodegradable COD to short-chain fatty acids
(SCFA’s).
3. Growth of non-polyP heterotrophs on SCFA.
GPS-X Technical Reference