Question

$BO{D}_5$ is:

• A. Waste decomposed in $5$ days
• B. Oxygen used in $5$ days
• C. Microorganisms killed in $5$ days
• D. Dissolved oxygen left after $5$ days

Answer 1

Answer: (B)

• $BO{D}_5$ stands for $5-$day Biochemical Oxygen Demand. The BOD test measures, oxygen is used as microbes breathe as they eat the contaminants in wastewater.
• $BO{D}_5$ is thus an indirect measure of the sum of all biodegradable organic substances in the water.
• The $BO{D}_5$ indicates the amount of oxygen that bacteria and other microorganisms consume in a water sample during the period of $5$ days at a temperature of ${20}^{o}C$ to degrade the water contents aerobically.
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• Option B is correct