BOD Volumetric Loading Calculator
Volumetric loading tells you how hard each cubic foot of aeration volume is working. Enter flow, BOD, and basin volume to compare your loading against typical design ranges.
Volumetric BOD Loading
| Item | Value |
|---|
How the calculation works
Formulas
BOD load (lb/day) = 8.34 × flow (MGD) × BOD5 (mg/L)
Volumetric loading (lb BOD ÷ 1000 ft³ · day) = BOD load (lb/day) ÷ (aeration volume (ft³) ÷ 1000)
BOD load (lb/day) = 8.34 × flow (MGD) × BOD5 (mg/L)
Volumetric loading (lb BOD ÷ 1000 ft³ · day) = BOD load (lb/day) ÷ (aeration volume (ft³) ÷ 1000)
| Process type | Typical volumetric loading (lb BOD / 1000 ft³ · day) |
|---|---|
| Extended aeration | 5–15 |
| Conventional activated sludge | 10–25 |
| High-rate / contact stabilization | 25–75 |
Notes & limitations
Typical loading ranges follow Metcalf & Eddy, Wastewater Engineering, and standard operator training references. They are screening bands, not permit limits — confirm against the current edition and your facility’s design basis.
- Use total aeration volume (all in-service basins). Volume out of service raises the loading on what remains.
- Volumetric loading pairs with F/M ratio: loading describes the tank, F/M describes the biomass. Check both when troubleshooting.
- Loadings above the conventional band can still work with more air, higher MLSS, and good settling — but watch dissolved oxygen and clarifier solids loading.
- Use flow-proportioned composite BOD values, not single grabs, for a representative loading.
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