Oxygen Requirement & Aeration Calculator
Estimate the oxygen demand and required blower air flow for an activated sludge process — carbonaceous demand plus nitrification.
Oxygen required
Blower air flow required
Formulas
Carbonaceous O₂ (kg/d) ≈ 1.1 × BOD₅ removed (kg/d)
Nitrogenous O₂ (kg/d) = 4.57 × TKN oxidized (kg/d)
Air (m³/d) = O₂ ÷ (0.232 × OTE) ÷ 1.2
1.1 is an empirical factor for carbonaceous demand; 4.57 g O₂ / g NH₄-N is stoichiometric for nitrification; air is 23.2% O₂ by mass with density ≈ 1.2 kg/m³. Denitrification credit and biomass synthesis are not included — treat results as planning estimates.
Carbonaceous O₂ (kg/d) ≈ 1.1 × BOD₅ removed (kg/d)
Nitrogenous O₂ (kg/d) = 4.57 × TKN oxidized (kg/d)
Air (m³/d) = O₂ ÷ (0.232 × OTE) ÷ 1.2
1.1 is an empirical factor for carbonaceous demand; 4.57 g O₂ / g NH₄-N is stoichiometric for nitrification; air is 23.2% O₂ by mass with density ≈ 1.2 kg/m³. Denitrification credit and biomass synthesis are not included — treat results as planning estimates.