GPS-X Technical Reference

309 Others Models
There are three parameters F max, F min and k a used in the model. The parameter F max may be
interpreted as the amount of metal required to remove the said component at very low
concentrations. It is general observation that the amount of metal required at lower concentration
of soluble component is much higher than the metal amount required when the concentration of
soluble component is higher. The parameter of F min, can be interpreted as the amount of metal
required to remove the said component at high concentrations. The parameter of k a signifies the
transition between the F min and F max. Higher values of k a will result in a very steep transition
between the F min and F max, essentially improving the removal efficiencies. Conversely, lower
values of k a will result in a mild transition and thus decreasing the removal efficiencies.
It is important to highlight here regarding the fate of the removed soluble components. As, the
flocculation process does not cause any mass loss, the removed soluble compounds are just
converted into their particulate state. The si, scol and snd are just transformed to xi, xs and xns
states respectively.
It should be noted that the value of these parameters depends on the environmental conditions
temperature, pH, mixing, and wastewater characteristics. Therefore, it is recommended that
adequate calibration is performed to find the appropriate values for specific cases.
GRIT CHAMBER
The model associated with this object is a simple empirical model where grit production is
directly proportional to the flow coming in the grit chamber. The amount of grit produced (in
grams per m 3 of influent) is user specified.
STRUVITE PRECIPITATION MODEL
The struvite precipitation reactor model represents an up-flow granular bed reactor with recycle.
The model uses a bed fluidization model to estimate the granular bed height and the solid
concentration in the effluent stream. An internal recycle is provided to achieve bed fluidization
velocity required by the user. A typical layout showing the application of struvite reactor is as
shown in Figure 11-6. Some typical outputs from the struvite precipitation model are as shown in
Figure 11-7and Figure 11-8.
GPS-X Technical Reference