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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]
Taunton (/ˈtɔːntən/) is the county town of Somerset, England. It is a market town and has a minster church. Its population in 2011 was 64,621.[2] Its thousand-year history includes a 10th-century monastic foundation, Taunton Castle, which later became a priory.[clarification needed] The Normans built a castle owned by the Bishops of Winchester. Parts of the inner ward house were turned into the Museum of Somerset and Somerset Military Museum. For the Second Cornish uprising of 1497, Perkin Warbeck brought an army of 6,000; most surrendered to Henry VII on 4 October 1497.[3][4] On 20 June 1685 in Taunton the Duke of Monmouth crowned himself King of England in a rebellion, defeated at the Battle of Sedgemoor. Judge Jeffreys led the Bloody Assizes in the Castle's Great Hall.[5]
The Grand Western Canal reached Taunton in 1839 and the Bristol and Exeter Railway in 1842. Today it hosts Musgrove Park Hospital, Somerset County Cricket Club, is the base of 40 Commando, Royal Marines, and is home to the United Kingdom Hydrographic Office on Admiralty Way.[6] The popular Taunton flower show has been held in Vivary Park since 1866, and on 13 March 2022, St Mary Magdalene parish church was elevated to the status of Taunton Minster.[7]
