Biogas, Digester Gas or Anaerobic Digester (AD) Gas typically refers to a mixture of gases produced by the breakdown of organic matter in the absence of oxygen. Biogas can be produced from regionally available raw materials such as recycled waste and is a renewable energy source and in many cases exerts a very small carbon footprint.
Biogas is produced by anaerobic digestion with anaerobic bacteria or fermentation of biodegradable materials such as manure, sewage, municipal waste, green waste, plant material, and crops. It is primarily methane (CH4) and carbon dioxide (CO2) and may have small amounts of hydrogen sulphide (H2S), moisture and siloxanes.
The gases methane, hydrogen, and carbon monoxide (CO) can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel; it can be used for any heating purpose, such as cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat.
Biogas plants are very efficient at digesting waste. Any other system will consume energy. Biogas plants produce energy.
Aside from the ecology the main benefits are the production of biogas and bio-fertilisers.
Additional benefits: electrical and heat power, bio-methane, savings on capital costs for waste cleaning systems when constructing new facilities.
Biogas production prevents methane emissions into the atmosphere. Its recovery is the best way to reduce global warming.
Biogas is practically produced as landfill gas (LFG) or digested gas. A biogas plant is the name often given to an anaerobic digester that treats farm wastes or energy crops. It can be produced using anaerobic digesters. These plants can be fed with energy crops such as maize silage or biodegradable wastes including sewage sludge and food waste. During the process, an air-tight tank transforms biomass waste into methane, producing renewable energy that can be used for heating, electricity, and many other operations that use an internal combustion engine, such as Alfagy, Schmitt, MAN or MWM engines.
There are two key processes: mesophilic and thermophilic digestion. Read more about the processes by reading our article about it here.