Sludge Age Calculator
Actual solids retention/sludge age mass inventory/(waste+effluent solids mass rate), not hydraulicHRT; complete matched biomass pool external. Actual independently established compatible SI units/model context; conditional arithmetic, not code compliance, engineering design or safe operation approval.
Description
Sludge age divides biological solids inventory by the total solids-removal rate.
Sludge age divides biological solids inventory by the total solids-removal rate.1
This tool calculates that retention quantity rather than hydraulic residence time.
When to use Sludge Age Calculator
Use this tool to calculate that retention quantity rather than hydraulic residence time.
How to use Sludge Age Calculator and how it works
- Prepare actualBiologicalSolidsInventoryKg, actualWasteSolidsKgPerDay, actualEffluentSolidsKgPerDay, with the units, conventions and assumptions below.
- Enter the required fields and run Sludge Age Calculator.
- Read result.value using the output definitions below.
- Correct any rejected inputs and rerun; interpret the result within the stated model and its assumptions.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| actualBiologicalSolidsInventoryKg | Actual Biological Solids Inventory Kg. Use the units and matching context stated in the calculation below. | number | Required; nonnegative; finite; other constraints below |
| actualWasteSolidsKgPerDay | Actual Waste Solids Kg Per Day. Use the units and matching context stated in the calculation below. | number | Required; nonnegative; finite; other constraints below |
| actualEffluentSolidsKgPerDay | Actual Effluent Solids Kg Per Day. Use the units and matching context stated in the calculation below. | number | Required; nonnegative; finite; other constraints below |
Supply nonnegative solids inventory and nonnegative waste and effluent solids removal rates using one mass and time basis. Require the combined removal rate to be positive and divide inventory by that rate. This residence-time ledger does not select a biological operating target.
sludgeAge=solidsInventory/(wasteRemovalRate+effluentRemovalRate) Apply the input ordering, units and branch conditions stated above.
| Output field | Meaning | Value type |
|---|---|---|
| result | Object containing the calculated or selected fields below. | object |
| result.value | Inventory residence time in days for kilogram and kilogram-per-day inputs. | number |
{
"input": {
"actualBiologicalSolidsInventoryKg": 10,
"actualWasteSolidsKgPerDay": 3,
"actualEffluentSolidsKgPerDay": 2
},
"output": {
"result": {
"value": 2
}
}
}Limitations and assumptions
The calculation uses the supplied observations and model inputs. It does not collect measurements, select a reference population or coefficient, or establish that the model applies to the actual case. The stated branch conditions and output units remain part of the result.
All fields require explicit values. Unexpected fields, wrong types, nonfinite numbers and sparse arrays are rejected. Alignment, bounds and supported-token rules are explained above; extremely large inputs or nonfinite results can also fail. Input errors differ from successful false comparisons, unavailable-domain flags and empty match lists.
Alternative or Complementary methods
Use Time of Concentration Calculator for a complementary operation: Watershed concentration time depends on a specified method and the applicable flow-path conditions.
Use CSTR Residence Time Calculator for a complementary operation: A nominal reactor space time compares working volume with matched volumetric throughput.
References
-
Sludge Age Calculator — tool.io
Similar or alternative tools
- Time of Concentration Calculator
Watershed concentration time depends on a specified method and the applicable flow-path conditions.
- CSTR Residence Time Calculator
A nominal reactor space time compares working volume with matched volumetric throughput.