BIOGAS

Biogas typically refers to a gas produced by the biological breakdown of organic matter in the absence of oxygen. Biogas originates from biogenic material and is a type of biofuel.

Biogas is made from organic waste matter after it is decomposed. The decomposition breaks down the organic matter, releasing various gases. The main gases released are methane, carbon dioxide, hydrogen and hydrogen sulphide. Bacteria carry out the decomposition or fermentation. The conditions for creating biogas have to be anaerobic. That is without any air and in the presence of water. The organic waste matter is generally animal or cattle dung, plant wastes, etc. These waste products contain carbohydrates, proteins and fat material that are broken down by bacteria. The waste matter is soaked in water to give the bacteria a proper medium to grow. Absence of air or oxygen is important for decomposition because bacteria then take oxygen from the waste material itself and in the process break them down.

The cheapest and easily obtainable biogas is gobar gas, which is produced by anaerobic fermentation of cattle dung. The biogas is burnt to raise steam, which can drive turbines to produce electricity.

Uses:

  • Biogas is used as cooking fuel. This is because biogas burns without smoke, has high calorific value, can be piped into kitchens directly from a plant and is cheaper in cost.
  • Biogas can be used to run electric engines such as pumps, as they cause less air pollution.
  • Biogas can be used for street lighting as it does not cause any smoke and the illumination obtained can be made to be quite adequate.

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