Calculate the daily BOD load and the approximate population equivalent.
BOD Loading
Formula
BOD load, lb/d = Q, MGD x BOD, mg/L x 8.34 Percent removal = (In - Out) / In x 100 Population equivalent = lb/d / 0.17
Inputs used
- Influent flow (MGD)
- Influent BOD (mg/L)
- Effluent BOD (optional, for removal) (mg/L)
- Population served (optional) (people)
Worked example (White River WRRF, fictional)
- Load = 8.0 x 220 x 8.34 = 14,678 lb/d
- Removal = (220 - 5) / 220 x 100 = 97.7%
- Per person = 14,678 / 72,000 = 0.204 lb/person/d
Tips
- Population equivalent assumes about 0.17 lb BOD per person per day; local values vary.
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.