What does BOD stand for?

• A. Biochemical Oxygen Demand
• B. Biological Oxygen Demand
• C. Basic Oxygen Demand
• D. Biochemical Oxygen Depletion

Answer: (A)

Biochemical Oxygen Demand is the standard term and the concept being tested. It refers to the amount of oxygen that microorganisms require to biologically oxidize organic matter in water under controlled conditions, typically measured as the decrease in dissolved oxygen over five days at 20°C (BOD5). This value provides a practical gauge of the organic pollution strength of a sample and helps assess how much oxygen will be consumed as wastewater is treated and as it flows into receiving waters, which is essential for designing treatment processes and protecting aquatic life. The other phrases aren’t the standard term used here: Biological Oxygen Demand is a common but incorrect form, Basic Oxygen Demand isn’t used in this context, and Biochemical Oxygen Depletion describes a condition rather than a specific measured demand.