Anaerobic digestion is a growing technology that offers sustainable solutions for organic waste management while contributing to the reduction of greenhouse gas (GHG) emissions. By transforming organic matter into biogas and digestate, this process offers many environmental benefits. This article explores how anaerobic digestion contributes to mitigating the impact of climate change.

1. Understand the methanization process

Methanation is a natural biological process of degradation of organic matter in the absence of oxygen, called anaerobic digestion. This process mainly produces two by-products:

• Biogas , composed mainly of methane (CH4) and carbon dioxide (CO2), can be used as a renewable energy source.

• Digestate , a nutrient-rich residue that can be used as agricultural fertilizer.

2. Reduction of GHG emissions through methanization

One of the main environmental advantages of methanization is its ability to reduce greenhouse gas emissions in several ways:

(a) Reduction of methane emissions from organic waste

Unrecovered organic waste is often left in the open air or landfilled, where it decomposes, releasing methane into the atmosphere. Methane is a greenhouse gas that is about 25 times more powerful than CO2 over a 100-year period. By capturing and recovering this methane, methanization can significantly reduce these emissions.

b) Substitution of fossil fuels

The biogas produced by methanisation can be used to produce electricity, heat or be injected into the natural gas network in the form of biomethane. This makes it possible to replace fossil fuels, thus reducing CO2 emissions linked to the combustion of coal, oil and gas.

c) Recovery of digestate and reduction of emissions linked to chemical fertilizers

Using digestate as an organic fertilizer helps limit the use of chemical fertilizers, the production of which has a high carbon footprint. By integrating digestate into agricultural practices, we promote carbon sequestration in the soil and limit emissions of nitrous oxide (N2O), a very powerful greenhouse gas.

3. Key figures for reducing emissions

According to the Agency for Ecological Transition (ADEME), methanization reduces greenhouse gas emissions by 50 to 90% compared to traditional organic waste management. For example:

• A methanization site treating 10,000 tonnes of organic waste per year avoids the emission of more than 4,000 tonnes of CO2 equivalent .

• Producing one tonne of biogas can avoid up to 2 tonnes of CO2 emissions by replacing fossil fuels.

4. Other environmental benefits of methanization

In addition to reducing GHGs, methanization contributes to other positive environmental aspects, such as:

• Sustainable waste management , avoiding landfill and incineration.

• The production of local renewable energies , promoting energy autonomy.

• Improving soil quality , thanks to the contribution of stabilized organic matter via digestate.

5. Conclusion: methanization, a solution for the future

In conclusion, methanization is an essential lever in the fight against climate change. It not only allows organic waste to be recovered, but also drastically reduces greenhouse gas emissions by limiting waste sent to landfill, replacing fossil fuels and promoting more sustainable agriculture.

Investing in methanization therefore represents both an ecological and economic opportunity for players in the sector, whether they are farmers, industrialists or local authorities.