The Processes of Anaerobic Digestion

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  • Topic: Anaerobic digestion, Methane, Carbon dioxide
  • Pages : 3 (796 words )
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  • Published : October 6, 2011
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Anaerobic digestion
Anaerobic digestion is a series of processes in which microorganisms break down biodegradable material in the absence of oxygen, used for industrial or domestic purposes to manage waste and/or to release energy. The digestion process begins with bacterial hydrolysis of the input materials in order to break down insoluble organic polymers such as carbohydrates and make them available for other bacteria. Acidogenic bacteria then convert the sugars and amino acids into carbon dioxide, hydrogen, ammonia, and organic acids. Acetogenic bacteria then convert these resulting organic acids into acetic acid, along with additional ammonia, hydrogen, and carbon dioxide. Finally,methanogens convert these products to methane and carbon dioxide. Anaerobic digestion is widely used as a source of renewable energy. The process produces a biogas, consisting of methane and carbon dioxide. This biogas can be used directly as cooking fuel, in combined heat and power gas engines or upgraded to natural gas quality biomethane. The utilisation of biogas as a fuel helps to replace fossil fuels. The nutrient-rich digestate that is also produced can be used as fertilizer. The first anaerobic digester was built by a leper colony in Bombay, India in 1859. Through scientific research, anaerobic digestion gained academic recognition in the 1930s. This research led to the discovery of anaerobic bacteria, the microorganisms that facilitate the process. Further research was carried out to investigate the conditions under which methanogenic bacteria were able to grow and reproduce. This work was developed during World War II, during which in both Germany and France there was an increase in the application of anaerobic digestion for the treatment of manure. Anaerobic digestion is particularly suited to organic material and is commonly used for effluent and sewage treatment. Anaerobic digestion is a simple process that can greatly reduce the amount of organic matter, which might...
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