GPS-X Technical Reference

Suspended Growth Models 104
Equation 6.23
GPS-X converts the airflow to U.S. standard conditions and then calculates the SOTR
using Equation 6.13. The OTR is calculated using Equation 6.24.
Equation 6.24
The oxygen mass transfer coefficient at field conditions is calculated using Equation
6.11. If the airflow is entered at U.S. or European standard conditions, the airflow at field
conditions is calculated using Equation 6.16.
Entering Mechanical Power
If mechanical power is entered, the SOTR in g/d is calculated using Equation 6.21. The
K La at field conditions is then calculated using Equation 6.19 and the OTR is calculated
using Equation 6.20.
DO Control
The user has the option of controlling the aeration supply to the reactor to maintain a
specific dissolved oxygen setpoint. In this case the model will calculate the necessary
oxygen mass transfer coefficient at field conditions to maintain the DO at the setpoint.
For diffused aeration with DO control, GPS-X uses Equation 6.12, Equation 6.13, and
Equation 6.14 to calculate the SOTR, OTR, and airflow. For mechanical aeration with
DO control, GPS-X uses Equation 6.20, Equation 6.21, and Equation 6.22 to calculate
the OTR, SOTR, and mechanical power
GPS-X Technical Reference