Question

Why is biogas called an excellent fuel?

Answer 1

Hint: Biogas is easily available and it does not harm the environment. Unlike other types of renewable energies, the process is natural, it does not require energy for the generation process.

Complete Answer:
Biogas is a mixture of gases (which primarily contain methane) formed by microbial activity and which can be used as fuel. The type of fuel produced depends on the microbes that are used and the organic substrates. Cattle excreta (dung), generally referred to as gobar, is abundant in certain bacteria. Dung may be used for biogas production, widely known as gobar gas.

The biogas plant has a dome-like structure made of bricks. In the mixing tank, slurry of cow-dung and water is fed into the digester. The digester is an enclosed chamber where oxygen is absent. Anaerobic microorganisms act on the mixture by decomposition or break down complex cow-dung slurry compounds. The decomposition process takes a few days to complete and produces gases such as carbon dioxide, hydrogen, hydrogen sulphide and nitrogen. The bio-gas is collected in the gas tank above the digester, from which it is extracted for use by pipes.

Biogas is both a sustainable and a clean energy source. The gas emitted by this process is non-polluting. It lowers greenhouse emissions. There is no combustion in the process, ensuring zero greenhouse gas emissions to the atmosphere. Bio-gas is an ideal fuel as it has a high heating potential and contains up to 75 per cent methane. Bio-gas is used for lighting too. The slurry that is left behind is regularly collected and used as manure and is high in nitrogen and phosphorus content.

Note: In addition to providing energy and manure, the large-scale use of bio-waste and sewage material provides a healthy and reliable waste management process.