Question

During sewage treatment, gases produced include

• A. Methane, hydrogen sulphide, carbon dioxide and hydrogen.
• B. Methane, oxygene and hydrogensulphide.
• C. Hydrogensulphide, methane and sulphur dioxide.
• D. Hydrogen sulphide, nitrogen and methane.

Answer 1

Answer: (A)

Methane, hydrogen sulphide, carbon dioxide and hydrogen.

Biogas contains a mixture of different gases which are produced by the breakdown of organic matter in the absence of oxygen. Biogas is composed of methane (CH${}_4$) and carbon dioxide (CO${}_2$) and may have small amounts of hydrogen sulphide (H${}_2$S), hydrogen (H${}_2$), moisture and siloxanes.

Thus, the correct answer is option A.