Biofilter Sizing
Size active nitrifying surface against combined TAN loads with supplied peak/rate/derating assumptions; no media rating, startup guarantee or fish safety certification.
Description
An areal biofilter rating relates TAN-nitrogen load to active treatment surface.
An areal biofilter rating relates TAN-nitrogen load to active treatment surface. A peak factor increases design load, while derating reduces the usable removal rate.1
Size active nitrifying surface against combined TAN loads with supplied peak/rate/derating assumptions; no media rating, startup guarantee or fish safety certification.
When to use Biofilter Sizing
Use this tool to size active nitrifying surface against combined TAN loads with supplied peak/rate/derating assumptions; no media rating, startup guarantee or fish safety certification.
Prepare the cohort, water, feed or equipment measurements for one consistent operating period. Confirm nitrogen reporting bases, dry/wet masses, flow units and supplied design assumptions.
How to use Biofilter Sizing and understand its results
- Prepare the cohort, water, feed or equipment measurements for one consistent operating period. Confirm nitrogen reporting bases, dry/wet masses, flow units and supplied design assumptions.
- Enter tanLoadsKgNPerDay, designPeakFactor, arealRemovalGramsNPerM2Day, operationalDeratingFraction using the field table and calculation rules, then run the tool.
- Read designLoadKgNPerDay, requiredActiveSurfaceAreaM2. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| tanLoadsKgNPerDay | Tan loads kg n per day | list of number | Required |
| designPeakFactor | Design peak factor | number | Required |
| arealRemovalGramsNPerM2Day | Areal removal grams n per m2 day | number | Required |
| operationalDeratingFraction | Operational derating fraction | number | Required |
Enter a nonempty nonnegative TAN-N load list, peak factor at least one, positive g N/m²/day rating and derating fraction greater than zero through one. Sum and peak the load, then convert kg to g and calculate required active area.
designLoadKgNPerDay=Σloads×peakFactor; areaM2=1000 designLoad/(arealRate×derating) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| designLoadKgNPerDay | Design load kg n per day | number |
| requiredActiveSurfaceAreaM2 | Required active surface area m2 | number |
{
"input": {
"tanLoadsKgNPerDay": [
1,
2
],
"designPeakFactor": 1.5,
"arealRemovalGramsNPerM2Day": 0.5,
"operationalDeratingFraction": 0.8
},
"output": {
"designLoadKgNPerDay": 4.5,
"requiredActiveSurfaceAreaM2": 11250
}
}Limitations and assumptions
Rates and derating are supplied assumptions. Startup, oxygen, alkalinity, temperature and actual nitrification are not predicted; active area is not yet media or reactor volume.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Biofilter Media Volume: Convert required active biofilter surface to accessible media and reactor volumes; distinct from TAN-to-area sizing and dependent on supplied accessibility and fill. For a complementary task, use Nitrification Rate: Measure net TAN disappearance and active-area-normalized rate across parallel streams; negative net removal is preserved and TAN disappearance alone does not prove nitrification.
References
-
Biofilter Sizing — tool.io
Similar or alternative tools
- Biofilter Media Volume
Convert required active biofilter surface to accessible media and reactor volumes; distinct from TAN-to-area sizing and dependent on supplied accessibility and fill.
- Nitrification Rate
Measure net TAN disappearance and active-area-normalized rate across parallel streams; negative net removal is preserved and TAN disappearance alone does not prove nitrification.