Q. Select the correct statement from the following
A) Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria
B) Biogas is produced by the activity of aerobic bacteria on animal waste
C) Methanobacterium is an aerobic bacterium found in rumen of cattle
D) Biogas, commonly called gobar gas, is pure methane
Explanation
[Solution from source] Activated sludge is the settled mass of aerobic bacterial flocs from secondary treatment, and part of it is pumped back as inoculum. Biogas is made by anaerobic methanogens such as Methanobacterium, and it is a mixture of mainly methane with CO₂ and H₂, not pure methane. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.