Work out bod load instantly with clear inputs, formula shown and shareable results.
BOD load is flow times concentration: 1 mg/L on 1000 cubic metres is 1 kilogram. Population equivalent converts that load to the number of people it represents at a standard rate, commonly 60 grams of BOD per person per day, which is how treatment works are sized and industrial dischargers are charged.
BOD load
Load (kg/day) = flow (m3/day) x BOD (mg/L) / 1000
Population equivalent
PE = load (g/day) / load per person per day
Discharge consents specify BOD limits as both concentration and load. Exceeding either is an offence in most jurisdictions.
Treatment capacity is limited by mass of organic matter, not concentration. A dilute high-flow discharge and a strong low-flow one can impose identical load and require identical aeration.
BOD5 is oxygen consumed in five days at 20 C, roughly 65-70% of ultimate BOD. Design standards specify which is meant, and they must not be interchanged.