Laboratory Equipment & Services Information System by Centralized Laboratory Management Office (CeLMO)

Biochemical Oxygen Demand (BOD) is a crucial parameter used to measure the amount of dissolved oxygen consumed by microorganisms during the decomposition of organic matter in water. It's a key indicator of the organic pollution level in water bodies.

A higher BOD value indicates a greater amount of organic pollutants present in the water, as microorganisms consume more oxygen during the decomposition process. High BOD levels can lead to oxygen depletion in water bodies, harming aquatic life and ecosystem balance. Therefore, BOD is an essential parameter monitored in environmental and wastewater management to ensure water quality and environmental health.

Here's how it works: Collection of Sample: A water sample is collected from the water body being tested, such as a river, lake, or wastewater treatment plant effluent. Incubation: The sample is incubated at a specific temperature (usually 20°C) in the dark for a specified period, typically 5 days. Measurement of Dissolved Oxygen: Initially, the dissolved oxygen (DO) concentration in the water sample is measured. This serves as the initial DO concentration (DOi). Measurement after Incubation: After the incubation period, the dissolved oxygen concentration is measured again. This is the final dissolved oxygen concentration (DOf). Calculation: The BOD is calculated using the formula: BOD=DOi−DOf The unit of BOD is usually expressed in milligrams of oxygen consumed per liter of water (mg/L), or parts per million (ppm).