BOD/COD Ratio Calculator
Calculate the BOD/COD ratio and assess wastewater biodegradability instantly. Determine the right treatment process for your effluent.
Free · No registration requiredEnter Wastewater Parameters
Values should be from the same sample, typically at 20°C. BOD₅ is the standard 5-day BOD.
Biochemical Oxygen Demand (5-day)
Chemical Oxygen Demand
How to Use This Calculator
- 1Enter the BOD₅ value (5-day Biochemical Oxygen Demand) of your wastewater sample in mg/L.
- 2Enter the COD value (Chemical Oxygen Demand) from the same sample in mg/L.
- 3Click "Calculate Ratio" to see the ratio and biodegradability assessment with treatment recommendations.
Formula
What is the BOD/COD Ratio?
The BOD/COD ratio is a key parameter used by environmental engineers to evaluate the biodegradability of industrial and municipal wastewater. BOD (Biochemical Oxygen Demand) measures the oxygen required by microorganisms to break down biodegradable organic matter, while COD (Chemical Oxygen Demand) measures the total oxygen demand of both biodegradable and non-biodegradable organics.
A higher BOD/COD ratio means a greater fraction of the organic matter is biodegradable, making biological treatment processes like activated sludge, MBBR, or SBR more effective and economical. A low ratio suggests the presence of refractory or toxic compounds that resist biological degradation.
Typical values for Indian industries: Municipal sewage (0.4–0.6), food processing (0.5–0.7), textile dyeing (0.1–0.3), pharmaceutical effluent (0.1–0.4), sugar/distillery (0.5–0.7).
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