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Anaerobic Digestion
Anaerobic digestion is a sequence of processes by which microorganisms break down biodegradable material in the absence of oxygen.[1] The process is used for industrial or domestic purposes to manage waste or to produce fuels. Much of the fermentation used industrially to produce food and drink products, as well as home fermentation, uses anaerobic digestion.
Anaerobic digestion occurs naturally in some soils and in lake and oceanic basin sediments, where it is usually referred to as "anaerobic activity".[2][3] This is the source of marsh gas methane as discovered by Alessandro Volta in 1776.[4][5]
The digestion process begins with bacterial hydrolysis of the input materials. Insoluble organic polymers, such as carbohydrates, are broken down to soluble derivatives that become available for other bacteria. Acidogenic bacteria then convert the sugars and amino acids into carbon dioxide, hydrogen, ammonia, and organic acids. In acetogenesis, bacteria convert these resulting organic acids into acetic acid, along with additional ammonia, hydrogen, and carbon dioxide amongst other compounds. Finally, methanogens convert these products to methane and carbon dioxide.[6] The methanogenic archaea populations play an indispensable role in anaerobic wastewater treatments.[7]
Anaerobic digestion is used as part of the process to treat biodegradable waste and sewage sludge. As part of an integrated waste management system, anaerobic digestion reduces the emission of landfill gas into the atmosphere. Anaerobic digesters can also be fed with purpose-grown energy crops, such as maize.[8]
Anaerobic digestion is widely used as a source of renewable energy. The process produces a biogas, consisting of methane, carbon dioxide, and traces of other 'contaminant' gases.[1] This biogas can be used directly as fuel, in combined heat and power gas engines[9] or upgraded to natural gas-quality biomethane. The nutrient-rich digestate also produced can be used as fertilizer.
With the re-use of waste as a resource and new technological approaches that have lowered capital costs, anaerobic digestion has in recent years received increased attention among governments in a number of countries, among these the United Kingdom (2011),[10] Germany,[citation needed] Denmark (2011),[11] and the United States.[12]
Basingstoke (/ˈbeɪzɪŋstoʊk/ BAY-zing-stohk) is the largest town in the county of Hampshire.[b] It is situated in south-central England and lies across a valley at the source of the River Loddon, at the far western edge of The North Downs. It is located 30 miles (48 km) north-east of Southampton, 48 miles (77 km) south-west of London, 27 miles (43 km) west of Guildford, 22 miles (35 km) south of Reading and 20 miles (32 km) north-east of the county town and former capital Winchester. According to the 2016 population estimate, the town had a population of 113,776.[c] It is part of the borough of Basingstoke and Deane and part of the parliamentary constituency of Basingstoke.
Basingstoke is an old market town expanded in the mid-1960s, as a result of an agreement between London County Council and Hampshire County Council. It was developed rapidly after the Second World War, along with various other towns in the United Kingdom, in order to accommodate part of the London 'overspill' as perceived under the Greater London Plan in 1944.[2] Basingstoke market was mentioned in the Domesday Book of 1086 and it remained a small market town until the early 1960s. At the start of World War II, the population was little more than 13,000. It still has a regular market, but is now larger than Hampshire County Council's definition of a market town.[3]
Basingstoke became an important economic centre during the second half of the 20th century and houses the locations of the UK headquarters of Motorola, The Automobile Association, De La Rue, Sun Life Financial, ST Ericsson, GAME, Barracuda Networks, Eli Lilly and Company, FCB Halesway part of FCB, BNP Paribas Leasing Solutions (the leasing arm of BNP Paribas in the UK) and Sony Professional Solutions. It is also the location of the European headquarters of the TaylorMade Golf Company. Other industries include IT, telecommunications, insurance and electronics.
