What is the purpose of anaerobic digestion ?

We hear a lot about anaerobic digestion, but what exactly is its purpose? In this article, we will introduce you to this technology that offers multiple advantages, ranging from renewable energy production to sustainable waste management.

Production of Renewable Energy

One of the main uses of anaerobic digestion is the production of renewable energy in the form of biogas. Biogas can be used in various ways to produce:

• Biomethane : Biogas is purified to remove CO2 and other impurities, resulting in biomethane. Biomethane, composed almost exclusively of methane, is injected directly into the city gas network.
• Electricity and heat : Biogas is burned in internal combustion engines or turbines to produce electricity and heat, known as cogeneration. The generated electricity is used to meet the energy needs of the installation, while the residual heat is recovered to heat the anaerobic digestion unit, adjacent buildings, and hot water.
• BioCNG : Biogas can be used as a biofuel for vehicles.

Valorization of Organic Waste and Livestock Effluents

Another key role of anaerobic digestion is the valorization of organic waste. Organic waste, such as food waste, agricultural waste (slurry, manure, and droppings), sewage sludge, crop residues, and more, can be used as input for anaerobic digestion. By converting this waste into biogas and digestate, anaerobic digestion allows the valorization of materials that would otherwise be disposed of by incineration, landfill, or composting. Anaerobic digestion also reduces the environmental impact of organic waste.

Reduction of Greenhouse Gas Emissions

Anaerobic digestion prevents the decomposition of organic waste in landfills, which releases methane into the atmosphere. Methane is a greenhouse gas 25 times more potent than carbon dioxide (CO2). Instead, anaerobic digestion captures the methane produced during waste decomposition and valorizes it as an energy source, thereby reducing greenhouse gas emissions.

Reduction of the Environmental Impact of Waste

Recycling organic matter through anaerobic digestion reduces the pressure on landfill sites, extending their useful life. It also helps reduce soil and groundwater pollution associated with the disposal of organic waste.

Production of Natural and Deodorized Fertilizer

Digestate, the solid residue resulting from the anaerobic digestion process, is rich in nutrients and is used as a natural fertilizer for agricultural soils. Thanks to anaerobic digestion, the digestate is odorless. This approach closes the nutrient cycle by valorizing organic waste to enrich soils, contributing to more sustainable agriculture.

Local Energy Production

Anaerobic digestion enables local energy production, with partial self-consumption for operators, as well as resale to the local population. This decentralized energy approach brings energy production closer to end users, reducing transport losses and strengthening the energy resilience of regions.

Anaerobic digestion is a promising technology that plays a crucial role in the transition to a circular and low-carbon economy. With investments in research, technological development, and appropriate policies, anaerobic digestion can be more widely adopted, significantly contributing to reducing greenhouse gas emissions, sustainable waste management, and promoting cleaner and more sustainable energy for future generations.