Question

Select the correct statement from the following:

• A. Methanobacterium is an aerobic bacterium found in the rumen of cattle.
• B. Biogas is produced by the activity of aerobic bacteria.
• C. Biogas is pure methane.
• D. Activated sludge in sediment tanks is a rich source of aerobic bacteria.

Hint:

Aerobic bacteria play a vital role in wastewater management.

Answer 1

The Correct Option is D

The correct statement is: Activated sludge in sediment tanks is a rich source of aerobic bacteria.

(A) Methanobacterium - Incorrect: These are strictly anaerobic archaea in cattle rumen.

(B) Biogas production - Incorrect: Biogas forms through anaerobic digestion, not aerobic processes.

(C) Biogas composition - Incorrect: Biogas contains ~60% methane plus CO₂ and traces of other gases.

(D) Activated sludge - Correct: This sewage treatment component contains aerobic bacteria that digest organic matter.

The correct answer is (D), as activated sludge systems rely on aerobic microbial communities.