Question

Percentage of methane present in biogas is
A. 75%
B. 60%
C. 50%
D. 43-45%

Answer 1

Hint: Biogas also known as gobar gas is one the natural renewable resource. It is utilized by the people for cooking, for lighting etc. It mainly consists of methane, carbon dioxide, hydrogen gas and little amount of hydrogen sulfide.

Complete Answer:
- Biogas is the gas produced by the breakdown of organic matter anaerobically (i.e. in the absence of oxygen). It is produced from raw materials like manure, plant material, agricultural waste, municipal waste, waste from sewage, green waste or food waste that are biodegradable in nature. It can be used as a source of energy as it is inflammable in nature.

- Biogas is produced by the microbial activity and which may be used as fuel. Certain bacteria like methanogens grow anaerobically on cellulosic plant material and thus produce large amounts of methane along with carbon dioxide, hydrogen gas. Methanobacterium is the most commonly used bacteria which are found in the anaerobic sludge during sewage treatment. These bacteria are also present in the rumen (a part of stomach) of ruminants like cattle, buffalo, sheep and goat. A lot of cellulosic material present in the food of cattle (because the plant contains cellulose in their cell wall) is also present in the rumen that helps in the breakdown of cellulose and plays an important role in deriving nutrition to the cattle.

- The composition of biogas is methane (about 60%), carbon dioxide (25-50%), hydrogen gas (about 1%) and hydrogen sulfide (0.1-0.5%)

The correct option is B i.e. 60%.

Additional information: The biogas production mainly takes place in the biogas plant that is consists of a concrete tank(10-15 feet deep) in which biodegradable organic wastes are collected and the slurry of dung is fed i.e. having bacteria called as Methanobacterium. A floating cover is placed over the slurry that rises when the gas is produced in the tank due to the microbial activity of the anaerobic microbes. The biogas has an outlet which is connected to a pipe to supply biogas to the nearby houses that is used for cooking and lightning in their houses.

Note: The technology of biogas production was developed in India mainly because of the efforts of KVIC (Khadi and Village Industries Commission) and IARI (Indian Agricultural Research Institute) to make the utilization of the organic matter and cattle dung in the positive way.