在沼泽、池塘、污水沟、粪池里,常常可以看到一个连一个的小气泡上升到水面,这些气泡中有部分可燃气体,用火柴一点可以燃烧起来。这种气体因常见在池沼中,故名沼气。沼气在自然界存在十分广泛。它是有机物质,如杂草、落叶、人畜粪便等在一定的 In swamps, ponds, gutters, and septic tanks, one after another can often see small bubbles rising up to the surface. Some of these bubbles have a combustible gas that can be burned with a matchstick. This gas is common in ponds, hence the name of biogas. Biogas exists in nature is very extensive. It is organic matter, such as weeds, leaves, livestock and poultry manure and so on in a certain