Question

Read the sources given and answer any four from the questions given below:

A biogas plant is where biogas is produced by fermenting the biomass. Biogas is a mixture of gases, mainly consisting of methane (50–70%) and carbon dioxide and has small amounts of nitrogen and hydrogen. It is produced from the raw materials such as agricultural waste, manure, municipal waste, plant waste, cow dung, sewage, green waste or food waste. It is a renewable source of energy with almost zero-emission. Biogas is produced by anaerobic fermentation of biomass by anaerobic bacteria or methanogens inside an anaerobic digester or bioreactor. The waste generated from a biogas plant can be converted into fertiliser and spread directly onto the fields. Biogas can be used as a fuel for any heating purpose, cooking and lighting.

1. Biogas is mainly a mixture of the following gases
   1. carbon dioxide and methane
   2. carbon dioxide and hydrogen
   3. methane and oxygen
   4. methane and nitrogen
2. Biogas is formed by the following process
   1. aerobic fermentation by bacteria
   2. anaerobic fermentation by yeast
   3. anaerobic fermentation by bacteria
   4. aerobic fermentation by yeast
3. Which of the following is not used as a raw material for biogas formation?
   1. agricultural waste
   2. cow dung
   3. food waste
   4. plastic waste
4. The biomass used to form biogas is digested by the
   1. biofertilisers
   2. Rhizobium bacteria
   3. methanogens
   4. bio-enzymes
5. The waste generated from the biogas can be used as
   1. feed for animals
   2. industrial fuel
   3. fuel for lighting
   4. fertilisers

Answer 1

1. carbon dioxide and methane
2. anaerobic fermentation by bacteria
3. plastic waste
4. methanogens
5. fertilisers