GPS-X Technical Reference

Attached Growth Models 250
Operational
In the Operational form, aeration constants are available similar to all aerated biological
units. Specific to the hybrid-system is the ability to specify two additional recycle
streams. These streams are internal recycle with carrier (if internal recycle carries
carrier with it) and flow from tank # with carrier (if the carrier can flow from one cell
to the next one).
Further model parameters are included in the mass transport, stoichiometric and
kinetic menu items in the hybrid-system model. (See Trickling Filter Model section in
this chapter)
Initialization
In addition to the standard initial volume input, the hybrid-system requires the reactor
portion filled by media (media or empty bed fill), which can be input in the Initial
Volume sub-menu form.
Display Variables
In addition to the standard effluent parameters, there are a number of fixed film specific
variables that can be displayed. These are accessed through the object's display variables
menu item.
DENITRIFICATION FILTER
The denitrification filter objects are found in the “Tertiary Treatment” group of objects, rather
than in the “Attached Growth” group, as the other biofilm objects.
The denitrification filter model is similar to the trickling filter model in hydraulic structure.
There are, however, a few fundamental differences:
1. The filter is assumed to be entirely flooded. There is no empty void space between
media, as in the trickling filter model.
2. The trickling filter model is assumed to be downflow, whereas there are two different
denitrification filter models: Upflow and Downflow, as shown in Figure 7-20.
GPS-X Technical Reference