Jobs
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]
Frome (/ˈfruːm/ ⓘ, FROOM) is a town and civil parish in eastern Somerset, England. The town is built on uneven high ground at the eastern end of the Mendip Hills, and centres on the River Frome. The town lies about 13 miles (21 km) south of the City of Bath, with the market towns of both Westbury and Warminster sitting 6.5 miles to the East. It forms part of the parliamentary constituency of Somerton and Frome. The population was 28,559 in 2021.[1]
Frome was one of the largest towns in Somerset until the Industrial Revolution, and was larger than Bath from AD 950 until 1650. The town first grew due to the wool and cloth industry; it later diversified into metal-working and printing, although these have declined. The town was enlarged during the 20th century but retains a large number of listed buildings, and most of the centre falls within a conservation area.
The town has road and rail transport links and acts as an economic centre for the surrounding area. It provides a centre for cultural and sporting activities, including the annual Frome Festival and Frome Museum.
In 2014, Frome was named by The Times the "sixth coolest town" in Britain.[2] It was shortlisted as one of three towns in the country for the 2016 Urbanism Awards in the 'Great Town Award' category.[3] In its 2018 and 2021 report on the "Best places to live in the UK", The Sunday Times listed Frome as the best in the South West.[4] In April 2019, Time Out listed Frome among 15 of the best weekend breaks from London.[5]
