Volumetric loading compares the BOD load with basin volume. Conventional activated sludge is often 20 to 40 lb BOD/1,000 ft³/d; extended aeration 10 to 25.
Aeration Basin Organic Loading
Formula
Loading, lb BOD/d per 1,000 ft³ = (Q, MGD x BOD x 8.34) / (Volume, MG x 133,680.6 / 1,000)
Inputs used
- Flow to aeration (MGD)
- Aeration influent BOD (mg/L)
- Aeration volume (MG)
Worked example (White River WRRF, fictional)
- BOD load = 8.0 x 150 x 8.34 = 10,008 lb/d
- Volume = 3.6 x 133,680.6 / 1,000 = 481.3 thousand ft³
- Loading = 10,008 / 481.3 = 20.8
Tips
- Use aeration influent BOD.
- Compare with design and with F/M.
Results are estimates for operator use. Check units and inputs, and confirm decisions with plant data and procedures.
This calculator also appears on ActivatedSludge.com, our consulting site. Results are for training and operator use; always follow your plant’s procedures.