GPS-X Technical Reference

161 Suspended Growth Models
The GPS-X MBR model calculates the removal of solids due to the membrane using a
mass balance and the solids capture rate (actually a fraction) specified in the
Input Parameters > Physical – Membrane form. The default solids capture rate has
been selected to provide a permeate TSS concentration of 1 mg/L or less for typical MBR
MLSS concentrations (i.e. 8,000 to 12,000 mg/L). A separate mass balance is applied to
each particulate component in the biological model.
In the simple mode, the permeate flow (and flux) is calculated using a volumetric balance
and the specified influent and pumped flows. In advanced mode, the permeate flux
through the membrane is modelled using a resistance-in-series model (Choi et al., 2000)
as shown below:
Equation 6.43
where:
J
∆P
μ
= permeate flux (m/s)
= trans-membrane pressure (kPa)
= viscosity of water (Pa’s)
Rm = intrinsic membrane resistance (m -1 )
Rc = cake layer resistance (m -1 )
Rf = fouling resistance (m -1 )
The trans-membrane pressure, ∆P, is specified in the Input Parameters > Operational
-Membrane Form, as described in the section below. The viscosity of water is calculated
using the following equation (Günder, 2001):
Equation 6.44
where:
T
= temperature (°C)
GPS-X Technical Reference