Reverse Osmosis Costing Method
Costing Method Parameters
The following parameters are constructed for the unit on the FlowsheetCostingBlock (e.g., m.fs.costing.reverse_osmosis) when applying the cost_reverse_osmosis costing method in the watertap_costing_package:
Description |
Symbol |
Parameter Name |
Default Value |
Units |
|---|---|---|---|---|
Standard RO (cost method = |
||||
Membrane replacement factor (fraction of membrane replaced/year) |
\(f_{mem,\, replace}\) |
|
0.2 |
\(\text{yr}^{-1}\) |
Membrane unit cost |
\(C_{mem}\) |
|
30 |
\(\text{USD}_{2018}\text{/m}^2\) |
High-pressure RO (cost method = |
||||
Membrane replacement factor (fraction of membrane replaced/year) |
\(f_{mem,\, replace}\) |
|
0.2 |
\(\text{yr}^{-1}\) |
Membrane unit cost |
\(C_{mem}\) |
|
75 |
\(\text{USD}_{2018}\text{/m}^2\) |
Costing Method Variables
The following variables are constructed on the unit block (e.g., m.fs.unit.costing) when applying the cost_reverse_osmosis costing method in the watertap_costing_package:
Description |
Symbol |
Variable Name |
Index |
Units |
|---|---|---|---|---|
Membrane area |
\(A_{mem}\) |
|
None |
\(\text{m}^2\) |
Capital Cost Calculations
Capital cost is dependent upon the RO membrane area, \(A_{mem}\), as shown in the equation below.
\[C_{cap,tot} = A_{mem} * C_{mem}\]
Operating Cost Calculations
The membrane replacement cost \(C_{op,\, mem}\) is calculated on an annual basis from the membrane cost and replacement frequency factor:
\[C_{op,\, mem} = f_{mem,\, replace}C_{mem}A_{mem}\]
Note
Energy consumption for RO units in WaterTAP is calculated via the separate pump costing method for the Pump unit model.