What does Biochemical Oxygen Demand measure?

What does Biochemical Oxygen Demand measure?

• A. Amount of oxygen needed by bacteria to decompose waste
• B. Dissolved oxygen concentration
• C. Temperature
• D. Alkalinity

Answer: (A)

Biochemical Oxygen Demand measures how much oxygen microorganisms need to biologically oxidize and decompose the organic matter in a water sample. This reflects the strength of organic pollution: more biodegradable material means more oxygen will be consumed as microbes break it down, leading to a higher BOD. In practice, a sample is incubated at a controlled temperature (commonly 20°C) for a set period (usually five days), and the drop in dissolved oxygen from start to end is used to calculate the BOD. A higher BOD indicates greater potential for oxygen depletion in streams or rivers, which can harm aquatic life. This is different from simply measuring dissolved oxygen, which is the amount of oxygen currently present, and from temperature or alkalinity, which affect oxygen dynamics or buffering capacity but do not quantify the biological oxygen demand.

Biochemical Oxygen Demand measures how much oxygen microorganisms need to biologically oxidize and decompose the organic matter in a water sample. This reflects the strength of organic pollution: more biodegradable material means more oxygen will be consumed as microbes break it down, leading to a higher BOD. In practice, a sample is incubated at a controlled temperature (commonly 20°C) for a set period (usually five days), and the drop in dissolved oxygen from start to end is used to calculate the BOD. A higher BOD indicates greater potential for oxygen depletion in streams or rivers, which can harm aquatic life. This is different from simply measuring dissolved oxygen, which is the amount of oxygen currently present, and from temperature or alkalinity, which affect oxygen dynamics or buffering capacity but do not quantify the biological oxygen demand.