GPS-X Technical Reference

Suspended Growth Models 94
CHAPTER 6
Suspended Growth Models
INTRODUCTION
This chapter examines the suspended-growth models that are available in the different GPS-X
libraries. Each of the biological models available in GPS-X is implemented in both the
completely mixed and plug-flow formats in many different unit process objects. The biological
model is the same, however, regardless of the hydraulic implementation.
Before discussing specific models, some common features are presented:
COMMON FEATURES
Modelling of Oxygen Transfer
The oxygen transfer model is based on theory presented in the USEPA Design Manual
for Fine Pore Aeration Systems (USEPA, 1989) and Mueller et al. (2002). The GPS-X
aeration model is suitable for accurate design of diffused and surface mechanical aeration
systems.
In GPS-X, oxygen transfer to the bulk liquid phase of a biological reactor is modelled
using a dynamic mass balance written for dissolved oxygen gas. For example, a
dissolved oxygen mass balance around a completely stirred tank reactor (CSTR) is shown
below in Equation 6.1.
Equation 6.1
GPS-X Technical Reference