GPS-X Technical Reference

237 Attached-Growth Models
Operational
The operational parameters are similar to the activated sludge model. Like the activated
sludge model, the aeration method can be chosen as either “Enter K La” or
“Enter Airflow”. No mechanical method is provided since this method is not appropriate
for the SBC.
Mass Transport
The parameters shown in Figure 7-5 are used by the SBC for the transport model
(diffusion) of the various components through the biofilm. Since there are insufficient
data in the literature concerning the diffusion of various components through a biofilm,
the values used for the diffusion through water are reduced by a constant fraction, shown
as reduction in diffusion in biofilm. The default diffusion coefficients shown for water
are used for the diffusion of components from the liquid layer to the first layer (outside)
of the biofilm. The rate of detachment and attachment is used for calculating the
sloughing rate and particulate components attachment to the biofilm.
Stoichiometric and Kinetic Parameters
The parameters shown in these menus refer to the biological reactions that are described
in Chapter 6 (page 94).
Display Variables
In addition to the standard effluent parameters, there are a number of fixed film specific
variables that can be displayed. They are the same as the trickling filter. These are
accessed through the following subheadings:
SBC Variables (see Trickling Filter Variables section in this chapter)
Liquid Concentrations (see Liquid Film Concentrations section in this
chapter)
2D Variables (see 2D Variables section in this chapter)
GPS-X Technical Reference