GPS-X Technical Reference

Suspended Growth Models 170
In the Operational input parameters menu, the only operational parameter to be
considered is the pump flow rate from the pumped connection on the lower right-hand
corner of the object. A PID control loop is available to be configured as well.
The remainder of the menus are similar to those shown in other completely mixed
biological reactors.
Model Output Variables
The output variables available for the anaerobic MBR object are a combination of those
from the conventional CSTR and the anaerobic digester. The filtrate and pump
connection points show flows, concentrations and operating cost variables for the liquid
streams. The gas connection (at the top of the object) shows the gas flow and
composition.
SEQUENCING BATCH REACTOR (SBR)
Common Features
The models associated with the sequencing batch reactor (SBR) object are combinations
of suspended-growth and sedimentation models. The various aerated and mixed phases
use a suspended-growth model, assuming a completely mixed hydraulic configuration,
while the settling and decanting phases use a reactive sedimentation model. The models
are combined together to form the whole unit process model.
Modes of Operation
There are three different SBR objects in GPS-X: the simple sequencing batch reactor
(SBR) object, the Advanced SBR object, and the Manual SBR object. All three objects
have the same functionality, appearance and choice of biological models. They differ in
the manner in which the user specifies the operation of the SBR unit.
The simple and advanced SBR objects require the specification of the timing and flow
rates to define the phases. The manual SBR object requires that the entire operational
cycle be defined by the user, either by having the liquid flows, air flows, and mixing on
interactive controllers, or as file inputs. The manual object is suited to operator training,
while the simple and advanced objects are typical for an SBR application.
When using multiple, parallel SBRs, it may be desirable to stagger the cycle times of the
units. For example, if two parallel SBRs are in use, each with a 6-hour cycle time, it may
be desired to shift one of the SBRs by 3 hours. If both have 3 hours of detention time,
then a continuous influent could be switched between the two unit processes. To specify
a timeshift for an SBR model using either the simple or advanced objects, the user enters
the desired timeshift for the timeshift for simple and advanced cycles parameter. The
timeshift parameter cannot be set to a value greater than the cycle time.
GPS-X Technical Reference