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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]
Rutland (/ˈrʌtlənd/) is a landlocked county in the East Midlands of England, bounded to the west and north by Leicestershire, to the northeast by Lincolnshire and the southeast by Northamptonshire.
Its greatest length north to south is only 18 miles (29 km) and its greatest breadth east to west is 17 miles (27 km). It is the smallest historic county in England and the fourth smallest in the UK as a whole. Because of this, the Latin motto Multum in Parvo or "much in little" was adopted by the county council in 1950.[2] It has the smallest population of any normal unitary authority in England. Among the current ceremonial counties, the Isle of Wight, City of London and City of Bristol are smaller in area. The former County of London, in existence 1889 to 1965, also had a smaller area. It is 323rd of the 326 districts in population.
The only towns in Rutland are Oakham, the county town, and Uppingham. At the centre of the county is Rutland Water, a large artificial reservoir that is an important nature reserve serving as an overwintering site for wildfowl and a breeding site for ospreys.
Rutland's older cottages are built from limestone or ironstone and many have roofs of Collyweston stone slate or thatch.
