Methane Collection - Methane Digestors and Landfill
Animal waste generates gases that are unpleasant for nearby human populations such as ammonia and contribute to global climate change: the decomposition process produces methane, which is estimated to be about 20 times more potent than carbon dioxide in its greenhouse gas effect. Methane also happens to be the main component of natural gas, a fossil fuel used in a variety of heating and electricity generating applications.
Methane digesters are enclosed tanks into which animal manure can be fed, combined with water, and subjected to a controlled temperature that optimizes the anaerobic (i.e., without oxygen) break down of the materials within. In the digester, the waste decomposes into methane, carbon dioxide, smaller amounts of other gases, and digestate, a nutrient-rich solid or slurry-like compound that makes a very good soil conditioner. The digester captures these by- products so that they can be used: the methane can be burned, and the digestate can be applied to suitable soils.
Digestors are often installed on agricultural operations so that the energy potential from the methane and the benefits of the digestate can be applied on-site. (Methane digesters are sometimes used by municipal authorities in their treatment of waste water or solid waste.) The methane is burned to generate electricity or heat facilities such as poultry or cattle houses, reducing operational costs considerably.
Another benefit of using methane digesters is the virtual elimination of odor from animal manure. Instead of decomposing freely as it normally would, the manure in a digester undergoes an enclosed and controlled chemical reaction, and the gases and odors are captured. The human nuisance is eliminated, and populations of flies and other pests are reduced, thus decreasing the diseases they can carry and the nuisance they create.