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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]
Glossop is a market town in the High Peak, Derbyshire, England, 12 miles (19 km) east of Manchester, 24 miles (39 km) northwest of Sheffield and 32 miles (51 km) north of the county town, Matlock, near Derbyshire's borders with Cheshire, Greater Manchester, South Yorkshire and West Yorkshire. It is between 150 and 300 metres (492 and 984 ft) above mean sea level, and lies just outside the Peak District National Park.
Historically, the name Glossop refers to the small hamlet that gave its name to an ancient parish recorded in the Domesday Book of 1086, and then the manor given by William I of England to William Peverel. A municipal borough was created in 1866, and the unparished urban area within two local government wards.[1] The area now known as Glossop approximates to the villages that used to be called Glossopdale, on the lands of the Duke of Norfolk. Originally a centre of wool processing, Glossop rapidly expanded in the late 18th century when it specialised in the production and printing of calico, a coarse cotton, and became a mill town with many chapels and churches, its fortunes tied to the cotton industry.
Architecturally, the area is dominated by buildings constructed of the local sandstone. There remain two significant former cotton mills and the Dinting railway viaduct. Glossop has transport links to Manchester, making the area popular for commuters.
