Sewage gas in city transportation

The bus is running with gas entering service in Bristol. The bus works with gas, which is converted into a super clean fuel by enriching and rich. Although the source is different, it is possible to separate the biometan gas used in the bus from natural gas as a smell. Natural gas is a liquid fuel consisting of a thousand years under hot and pressure from dead organic ingredients. Yet biometan is prepared of airless digestion. Micro-organisms in oxygen-free environment are rich biogas in methane by breaking human stools and foodstuffs. Then this gas is surrounded by carbon dioxide and other substances.