Biogas Energy
We have become so advanced in technology that we are able to use the organic waste and produce a gas that can be used by the people living in that society, thus saving on the increased exploitation of the natural resources. Biogas energy is one such example of innovations. There are certain bacteria that are known to grow under anaerobic conditions, and they produce a lot of methane, carbon dioxide, and hydrogen. And this mixture of gases can be used for a variety of chores. Methanogens are the bacteria that produce the gaseous mixture. One such methanogen is Methanobacterium, which is present in the cattle food. The cattle digest these bacteria with the food, and the dung produced by the cattle contain these methanogens that are used in the production of gobar gas.
A mixture of gases that are produced by the anaerobic decomposition of the organic matter like municipal waste, plant residue, agricultural waste, food waste, etc. is called biogas. Biogas is usually composed of carbon dioxide, methane, and a small amount of hydrogen sulphide and moisture.
Biogas Plant
It is a dome-like structure in which the production of the biogas takes place. The biogas plant has a source to supply the feedstock, a digestion tank to produce biogas, a biogas recovery unit to separate the biogas that is produced and the heat exchanger to maintain the temperature of the digester that is required for the production of the biogas. The digester is a sealed chamber in which the biowaste and the slurry are decomposed using anaerobic decomposition. The slurry is then covered with a floating cover so that the gas produced due to microbial activity can make the cover rise upwards. The biogas thus produced is drawn out through the pipes and then supplied to the respective places through the connected pipes. This slurry is removed through an outlet and then later used as a fertilizer. This biogas can be used for cooking or lighting.
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Biogas Production in Landfill
Besides the gobar gas plant, biogas can also be produced in the Landfills. The organic matter present in the landfills decomposes naturally, and the biogas is produced as a result of the activity of these microbes. Methanobacteria that are present in the organic waste decompose the waste and produce a mixture of gases called biogas. There is a network of interconnected pipes present in the landfill to collect the biogas that is produced—the composition of the gas changes with time. After a year of production, the composition of methane and carbon dioxide changes to 60% and 40%, respectively. This is gaining popularity and acceptance as this method prevents the explosion that could be caused due to the collection of methane gas in the landfill, and it also prevents the loss of methane into the atmosphere. The biogas produced in landfills is used to create electricity.
Substrates Required in Biogas Production
Advantages of Biogas
The advantages of the biogas are: -
Renewable Source of Energy: Biogas is a renewable source of energy because the production of the biogas is dependent on the generation of the waste, which is an endless process.
Cheaper Technology: The installation of the biogas requires a very small cost, and it becomes self-sufficient in a duration of about 3-4 months.
Non - Polluting: The biogas burns without smoke, and thus no harmful gases like carbon dioxide, carbon monoxide, sulphur dioxide, and nitrous oxide are released.
Generates Employment: The setup of biogas creates a work opportunity for thousands of people in rural areas.
Reduces Landfills: The slurry that is leftover after the production of biogas is used as a fertilizer. The method of disposal is safe and environmentally friendly, and so no space is wasted in the form of landfills.
Disadvantages of Biogas
The disadvantages of biogas are:
Contains Impurities: The biogas contains several impurities which are difficult to remove even after a number of rounds of purification. Biogas, when compressed to be used as fuel, proves to be highly corrosive to the container.
Unstable and Hazardous: When methane comes in contact with oxygen, it reacts to produce carbon dioxide. The highly inflammable nature of the methane makes it prone to explosions.
Not Efficient on a Large Scale: Since it is not easy to enhance the efficiency of biogas, it is not viable economically to use biogas on a huge scale.
FAQs on Production of Biogas
Question 1. What are the Uses of Biogas?
Answer: Biogas is a renewable source of energy that has various applications, and it can be used for cooking, heating, lighting, etc. It is also used for producing methanol, electricity, and for the production of steam. The biogas can be used at home for coking when it is transferred from the digester through the connected pipes. As compared to other resources like wood, coal, etc., biogas produces less pollution while cooking. The heat is produced instantly after the ignition, and thus you need not wait for the generation of heat as in the use of other fuels like wood. Biogas can also be used as a fertilizer and for the production of indoor light.
When the biogas is combusted externally, the Stirling motor is heated with the help of the heat exchanger. The electricity is generated when the expansion of the gas takes place in the Stirling motor. The use of electricity thus produced is limited as the efficiency of it is low and it is also expensive.
Question 2. What are the Advantages of Biogas?
Answer: The following are the advantages of the biogas:
It improves the sanitation of the surroundings.
Biogas is a safe, cheap, renewable source of energy.
It is used for domestic and street lighting and cooking.
It is also used for driving engines.
Biogas can be burnt in stoves to provide heat.
It is easy to generate, transport, and store.
It is eco-friendly and does not cause any pollution.
The residue left after the production of biogas can be used as manure.
