During the secondary treatment phase of a modern eco-friendly sewage treatment plant, compressed air is pumped into a tank filled with microorganisms. What is the name of this widely used biological wastewater treatment process?

Answer: C. Activated Sludge Process

• Answer: C
• Explanation: The Activated Sludge Process uses air (aeration) and a biological floc composed of bacteria and protozoa to break down dissolved organic matter. The air keeps the microbes suspended and supplied with oxygen, accelerating natural decomposition before the water moves to final filtration.

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