Biogas
Biogas is a gaseous renewable energy source[1] produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste, wastewater, and food waste. Biogas is produced by anaerobic digestion with anaerobic organisms or methanogens inside an anaerobic digester, biodigester or a bioreactor.[2] The gas composition is primarily methane (CH
4) and carbon dioxide (CO
2) and may have small amounts of hydrogen sulfide (H
2S), moisture and siloxanes. The methane can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel; it can be used in fuel cells and for heating purpose, such as in cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat.[3]
After removal of carbon dioxide and hydrogen sulfide it can be compressed in the same way as natural gas and used to power motor vehicles. In the United Kingdom, for example, biogas is estimated to have the potential to replace around 17% of vehicle fuel.[4] It qualifies for renewable energy subsidies in some parts of the world. Biogas can be cleaned and upgraded to natural gas standards, when it becomes bio-methane. Biogas is considered to be a renewable resource because its production-and-use cycle is continuous, and it generates no net carbon dioxide. From a carbon perspective, as much carbon dioxide is absorbed from the atmosphere in the growth of the primary bio-resource as is released, when the material is ultimately converted to energy.
Dorchester (/ˈdɔːrtʃɛstər/ DOR-ches-tər) is the county town of Dorset, England. It is situated between Poole and Bridport on the A35 trunk route. A historic market town, Dorchester is on the banks of the River Frome to the south of the Dorset Downs and north of the South Dorset Ridgeway that separates the area from Weymouth, 7 miles (11 km) to the south. The civil parish includes the small town of Poundbury and the suburb of Fordington.
The area around the town was first settled in prehistoric times. The Romans established a garrison there after defeating the Durotriges tribe, calling the settlement that grew up nearby Durnovaria; they built an aqueduct to supply water and an amphitheatre on an ancient British earthwork. After the departure of the Romans, the town diminished in significance, but during the medieval period became an important commercial and political centre. It was the site of the "Bloody Assizes" presided over by Judge Jeffreys after the Monmouth Rebellion, and later the trial of the Tolpuddle Martyrs.
In the 2011 census, the population of Dorchester was 19,060, with further people coming from surrounding areas to work in the town which has six industrial estates. The Brewery Square redevelopment project is taking place in phases, with other development projects planned. The town has a land-based college, Kingston Maurward College, The Thomas Hardye School, three middle schools and thirteen first schools. The Dorset County Hospital offers an accident and emergency service, and the town is served by two railway stations. Through vehicular traffic is routed round the town by means of a bypass. The town has a football club and a rugby union club, several museums and the biannual Dorchester Festival. It is twinned with three towns in Europe. As well as having many listed buildings, a number of notable people have been associated with the town. It was for many years the home and inspiration of the author Thomas Hardy, whose novel The Mayor of Casterbridge uses a fictionalised version of Dorchester as its setting.