GPS-X Technical Reference

Suspended Growth Models 106
The SOTE for coarse bubble and jet diffusers is dependent upon the airflow per diffuser
and the diffuser submergence.
In all the SOTE correlations, the airflow per diffuser has been limited to be within the
ranges used for calibration. The correlations are empirical and should not be extrapolated
outside of the calibration range. The ranges are used as follows:
Fine Bubble
Ceramic Disc:
Ceramic Dome:
Membrane Disc:
Membrane Tube:
0.5 ≤ AF ≤ 5m 3 /h/diffuser
0.5 ≤ AF ≤ 4.4 m 3 /h/diffuser
0.8 ≤ AF ≤ 5 m 3 /h/diffuser
0.8 ≤ AF ≤ 15 m 3 /h/diffuser
Coarse Bubble
Jet
14 ≤ AF ≤ 58 m 3 /h/diffuser
8 ≤ AF ≤ 140 m 3 /h/diffuser
GPS-X applies a warning message to the log window if the airflow per diffuser is outside
the ranges given above.
SOTE in Deep Tanks
The fine bubble SOTE correlation is modified for tanks deeper than 8 m. Work by Pöpel
and Wagner (1994) has shown that the SOTE does not continue to increase linearly with
the depth of submergence beyond depths of approximately 8 m (see Figure 8 in Pöpel and
Wagner (1994)). At depths greater than 8 m the SOTE starts to level off so that the
SOTE can never be greater than 100 %.
An extra quadratic term in diffuser submergence is added to Equation 6.25 when the
diffuser submergence is greater than 8 m, as shown in Equation 6.27.
Equation 6.27
GPS-X Technical Reference