Overview - Anaerobic Digestion
Anaerobic digestion of wastes provides biogas. Biogas contains about 60% methane that can be
used to generate electricity or used for heat or for fuel for vehicles. Any animal manure, human
sewage or food waste will produce methane during anaerobic digestion. Natural gas is methane.
Biogas can be "cleaned" to yield purified methane that can be used in the natural gas pipelines.
Methane from biogas is an excellent alternative energy source. Using methane for energy helps the
environment by replacing the use of non-renewable fossil fuels with renewable energy and by
taking the methane out of the atmosphere. Methane is a green house gas that has 21 times the
heating effect as carbon dioxide. Biogas methane is renewable unlike natural gas which is mined
from underground wells and is a non-renewable fossil fuel.
There is also a large amount of heat energy dissipated from the Anaerobic Digestion system which
can be channeled into localised heating systems for water, housing or possibly other agricutural
functions such as grain drying.
Anaerobic Disegtion in Relation to Farming
Recently hundreds of farms in Mexico and South America have installed anaerobic digesters to collect
and use methane from manure to provide energy for farm use. Many of these digesters have been paid
for by a company that aggregates and sells carbon credits to factories and utility companies in
countries that signed agreements under the Kyoto protocol to reduce greenhouse emissions. Carbon
credits are earned by reducing greenhouse gas emissions such as carbon dioxide and methane. These
credits have considerable value.