GPS-X Technical Reference

265 Sedimentation and Flotation Models
The solids flux due to flotation is specified by the same double exponential function used
for sedimentation (Equation 8.1). The parameters within Equation 8.1 are altered to
account for effects of flotation:
v sj
v max
rhin
rflo
X j o
= floating velocity in layer j (m/d)
= floating velocity with optimal air-to-solids ration (m/d)
= hindered zone floating parameter (m 3 /gTSS)
= free floating zone floating parameter (m 3 /gTSS)
= X j – X min, where X min is the minimum attainable suspended solids
concentration, X j is the suspended solids concentration in layer j
The minimum attainable solids concentration in a layer, X min, is calculated as a fraction
(non-floatable fraction of fns) of the influent solids concentration to the DAF unit:
Equation 8.6
It is subject to a maximum value specified by the user, the maximum non-floatable
solids or X minmax. The floating velocity is lower bounded to zero, so that if the user
specifies parameter values that would result in floating velocities becoming negative, a
warning message is printed in the simulation Log window. The floating velocity is also
subject to a maximum value specified by the user, the maximum floating velocity or
v bnd.
Model Parameters
This section of the chapter contains a description of the various model parameters and
inputs that the user encounters when using the flotation model.
GPS-X Technical Reference