ElectroNP (ZO)
- This electrochemical nutrient removal (ElectroNP) unit model
is a zero-order model that enables the user to specify performance in terms of solute rejection
supports a single liquid phase only
supports steady-state only
assumes isothermal conditions
Degrees of Freedom
The zero-order electroNP model has at least 6 degrees of freedom that should be fixed for the unit to be fully specified. Typically, the following variables are fixed:
inlet volumetric flow rate
inlet temperature
inlet pressure
electricity intensity
dosage of magnesium chloride per phosphorus removal
There is 1 degree of freedom for each solute in a given property model:
inlet solute concentration
Model Structure
This electroNP model is built based on the IDAES Separator module. It consists of one inlet port and two outlet ports as
treated and byproducts. The SplittingType is set to componentFlow.
Sets
Description |
Symbol |
Indices |
|---|---|---|
Time |
\(t\) |
[0] |
Phases |
\(p\) |
[‘Liq’] |
Components |
\(j\) |
[‘H2O’, ‘Solute’]* |
*Solute depends on the imported property model, and more than one solute can be provided.
Variables
Description |
Symbol |
Variable Name |
Index |
Units |
|---|---|---|---|---|
Mass recovery fraction of water |
\(R_{H2O}\) |
recovery_frac_mass_H2O |
[t] |
\(\text{dimensionless}\) |
Removal fraction of component |
\(r_j\) |
removal_frac_mass_comp |
[t, ‘byproduct’, j] |
\(\text{dimensionless}\) |
Electricity consumption |
\(E\) |
electricity |
[t] |
\(\text{kW}\) |
Electricity intensity with respect to phosphorus removal |
\(EI\) |
energy_electric_flow_mass |
None |
\(\text{kWh/kg}\) |
Dosage of magnesium chloride per phosphorus removal |
\(D_{MgCl2}\) |
magnesium_chloride_dosage |
None |
\(\text{dimensionless}\) |
Magnesium chloride flowrate |
\(Q_{MgCl2}\) |
magnesium_chloride_dosage |
[t] |
\(\text{kg/hr}\) |
The electroNP model also has two mutable parameters:
Description |
Symbol |
Variable Name |
Index |
Units |
|---|---|---|---|---|
Phosphorus removal fraction |
\(r_P\) |
P_removal |
None |
\(\text{dimensionless}\) |
Nitrogen removal fraction |
\(r_N\) |
N_removal |
None |
\(\text{dimensionless}\) |
NOTE: Removal fractions for other components are fixed to 0
Equations
Description |
Equation |
|---|---|
Water removal |
\(r_{H2O} = 1 - R_{H2O}\) |
Phosphorus removal |
\(r_{S_{PO4}} = r_P\) |
Nitrogen removal |
\(r_{S_{NH4}} = r_N\) |
Energy consumption |
\(E = EI Q_{byproduct, S_{PO4}}\) |
MgCl2 demand |
\(Q_{MgCl2} = D_{MgCl2} Q_{byproduct, S_{PO4}}\) |