GPS-X Technical Reference

307 Others Models
The set of above equations are solved simultaneously to calculate the soluble phosphorus
removal in the in-line chemical dosing object. The main calibration parameter in the
model is the solubility product of the metal phosphates. The default values are provided
based on the evaluation of reported values in literature. The values however may need to
be adjusted to account for the differences in wastewater characteristics, mixing regimes
and other parameters which affect the P-precipitation process.
In addition to P-precipitation, the metaladd model also models the removal of colloidal
COD (scol), soluble inert COD (si) and soluble organic nitrogen (snd) through
flocculation. Following assumptions are used in the formulation of this empirical
flocculation model.
1. The metal dose to flocculate unit soluble component is a function of the soluble
component concentration.
2. The metal dose required per unit soluble component removed is expressed as an
exponential function with minimum bound.
The equation for metal dose per unit ss removed can be expressed as below:
Equation 11.6
where:
F
= metal consumed per unit soluble component at soluble component
concentration C, g Me/g component
C = Concentration of soluble component, g/m 3
F max
F min
= maximum metal consumption per unit soluble component, g Me/g
component
= minimum metal consumption per unit soluble component, g Me/g
component
k a = affinity factor, m 3 /g
GPS-X Technical Reference