Select the correct statement from the following

Options

A. Biogas is produced by the activity of aerobic bacteria ono animal waste
B. Methanobacterium is an aerobic bacterium found in remen to cattle
C. Biogas , commonly called gobar gas, is pure methane
D. Activated sludge-sediment in settlement tanks of sewage treatment plant is a right source of aerobic bacteria

Answer

D

Explanation

Out of the following statements (d) is correct because activated sludge is a process dealing with the treatment of sewage (or industrial waste water) combined with organisms to develop a biological flock, which reduces the organic content of the sewage. Sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria because small amounts are used as inoculum in secondary treatment or biological treatment stage of sewage treatment.