GPS-X Technical Reference

Attached Growth Models 232
Mass Transport
The parameters shown in Figure 7-5 are used by the RBC 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. These are accessed through the object’s Display
Variables menu item.
RBC 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)
SUBMERGED BIOLOGICAL CONTACTOR (SBC) MODEL
Introduction
The submerged biological contactor (SBC) model is a modification of the RBC model for
units that are air driven or are provided with supplemental aeration. Units with
supplemental aeration tend to be more submerged than conventional RBCs (conventional
RBCs are generally 40 percent submerged) providing additional contact of the media
with the influent, since the unit is not dependent on ambient air for oxygen.
GPS-X Technical Reference