What does the BOD5 test measure and why is it important in wastewater treatment?

• A. It measures the amount of oxygen consumed by microorganisms to degrade biodegradable organic matter over 5 days; indicates organic strength and helps evaluate treatment performance.
• B. It measures the dissolved oxygen concentration in the effluent at 5-hour intervals.
• C. It measures the rate of chemical oxidation of organics in 5 minutes.
• D. It measures the amount of sludge produced by the plant in 5 days.

Answer: (A)