Biogas describes the gases produced through the decomposition of organic matter. These gases result from the breakdown of sewage waste, animal manure and crop residues, as well as from energy crops designed to produce the highest quality biogas. Biogas is becoming increasingly popular as a clean alternative energy source. and is being used worldwide.
Digesters
A biogas digester is the container or system used to decompose the organic waste and generate biogas. In order to produce biogas, the waste needs to be decomposed anaerobically, which means it cannot be done in the presence of oxygen. As such, the container needs to be airtight and the bacteria chosen to digest the waste needs to be anaerobic bacteria or it will die. Some digesters are similar in setup to a septic tank except that a system siphons off and stores the gas produced.
Composition
Typical biogas is about 50 to 80 percent methane, 20 to 50 percent carbon dioxide and trace amounts of other gases. Biogas can be used in many applications as is, but there are methods to purify the biogas, making it an even better fuel source. Some biogas equipment requires removing hydrogen sulfide before the biogas can be used. Removing some of the carbon dioxide also helps equipment run more efficiently. Purified biogas is referred to as renewable natural gas.
Uses
There is a variety of ways to use biogas to produce energy. It can be combusted (burned) in boilers and hot water heaters, producing hot water or steam; compressed for vehicular use; or fed into the natural gas grid. One of the main benefits of biogas usage is that it can be large- or small-scale. Farmers who have an abundance of organic waste can install digesters to decompose the waste and produce biogas, which they can use throughout the farm to provide heat and fuel. Since waste treatment plants and garbage dumps produce biogas on a much larger scale, they can use the biogas to power the plant and its vehicles or sell the biogas to a natural gas company.
Benefits
Biogas is a renewable resource, so there will never be a shortage of it as there is now with fossil fuels. Collecting organic materials and decomposing them anaerobically prevents the release of nitrous dioxide and methane into the environment. Release of these two greenhouse gases from animal manure is a major contributor to global warming. Farms utilizing biogas could become self sufficient, rather than having to pay for power, reducing the total amount of waste product.
Tags: produce biogas, animal manure, carbon dioxide, organic waste, waste needs