How Do Biogas Systems Work?
The basic elements of a typical family biogas system are an outhouse, a pig or cow pen, and fermentation tanks for the waste matter. The system works as follows: Waste matter from the outhouse and livestock pen is channeled into a buried, sealed fermentation tank. As the waste matter decomposes, it produces methane gas which is led off to the family house through a tube connected to a cooking stove and perhaps a gas lamp. One biogas system generally produces enough gas to meet all the cooking needs of a family, and enough extra to fuel a gas lamp. As the waste matter decomposes in the sealed tank, it also produces pressure and heat. The pressure drives the bottom layer of waste matter out of the sealed fermentation tank through a channel into another smaller tank where it is stored for use as fertilizer. The heat kills most of the bacteria and parasite eggs in the waste matter, making the newly-produced fertilizer cleaner and safer than the untreated sewage rural communities often use
