“Water is life, and clean water means health.” — Audrey Hepburn

Introduction: The Importance of Biochemical Oxygen Demand (BOD)

Water is an indispensable resource, but its quality is often compromised by organic pollution. Biochemical Oxygen Demand (BOD) is a key metric for determining water pollution, quantifying the oxygen required by microorganisms to decompose organic matter. This parameter is crucial for maintaining water quality and ensuring the sustainability of aquatic ecosystems. Studies show that untreated wastewater can increase BOD levels by 50–70% in natural water bodies, endangering aquatic life.

“Without data, you’re just another person with an opinion.” — W. Edwards Deming

Definition and Significance of BOD

BOD measures the dissolved oxygen consumed by aerobic microorganisms in the biological oxidation of organic matter, expressed in milligrams per liter (mg/L). For comparison:

Pristine rivers often have BOD levels below 1 mg/L.

Moderately polluted waters exhibit BOD values between 3–5 mg/L.

Industrial effluents can raise BOD to 20–30 mg/L or higher.

High BOD values signal oxygen depletion, which disrupts aquatic ecosystems. According to the World Health Organization, over 80% of wastewater globally is discharged untreated, significantly contributing to elevated BOD levels.

“Science is organized knowledge.” — Herbert Spencer