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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]
Mapperley is a residential and commercial area of north-eastern Nottingham, England. The area is bounded by Sherwood to the north-west, Thorneywood to the south and Gedling to the east.
At various periods the terms 'Mapperley' and 'Mapperley Plains' have been applied to lands, on either side of Woodborough Road (B684), from a point at the junction of Mapperley Road, north-east for a distance of some 3+3⁄4 miles (6.0 km), to that point where the road forks towards Woodborough village. The stretch of Woodborough Road from Mapperley Road to Porchester Road is called 'Mapperley Plains' on Jackson's map of 1851–66, for example.[1][2] This section considers the history of the suburb within the present day city boundary.
The origins of the city of Nottingham suburb called Mapperley seem to be found in the fourteenth century. Writing in the 1670s about lands in the lordship of Basford (i.e. west of present-day Woodborough Road) which were called cornerswong, Dr Robert Thoroton, notes:
In the time of Richard the second (reigned 1377-99), Thomas Mapurley was a considerable man at Nottingham…. He, or his posterity, became possessed of the chiefest part of these grounds, which was the occasion of them being called Maperley's Closes; and since there being a cottage-house or two, and some odd barns erected, it goes for a small Hamlet called Mapurley.[3]
