Biomethanation (also called anaerobic digestion) is the process by which organic waste is fermented and decomposed in the absence of oxygen, notably generating methane.
This process is a naturally occurring phenomenon commonly found in sediments, marshes, and landfills. It can also be replicated in digesters (or methanizers) through a highly technical and controlled process.
The output of this process is biogas, a renewable natural gas composed mainly of methane (50% to 70%), along with carbon dioxide (CO2), varying quantities of water vapor and hydrogen sulphide (H2S), as well as other compounds (contaminants). This biogas can be used as an energy carrier (electricity, hot water, heating fuel). When purified, the biogas becomes biomethane, which can be used as biofuel or be directly injected into the natural gas grid.
The residue from this process, called digestate, makes an excellent fertilizer that can be spread directly on farmland or composted to become methacompost.
The stages of the biogas upgrading process, from harvesting the raw materials to using the biomethane:
An entire ecosystem forms around the biogas upgrading plant to convert organic waste from various sources into renewable energy for a variety of uses.
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