Definition of agricultural anaerobic digestion
Anaerobic digestion is a natural biological process that transforms organic matter (plant waste, manure, etc.) into renewable energy (biogas mainly composed of methane) and natural fertilizer (digestate, undegraded organic matter). We will speak more specifically of agricultural anaerobic digestion or "on-farm" anaerobic digestion when the materials used come from agricultural activities.
The anaerobic digestion process can occur spontaneously and naturally in certain environments such as marshes, but, in agriculture, dedicated installations called "digesters" are set up to induce it.
The stages of agricultural anaerobic digestion
Understanding agricultural anaerobic digestion requires knowing the different stages that constitute it.
Collecting organic matter
The first step in agricultural anaerobic digestion is to collect organic matter that can be digested. This matter can come from various sources, such as plant waste or harvest residues. In agricultural anaerobic digestion, materials from agricultural activities such as livestock effluents (manure, slurry), harvest residues, waste from the agri-food industry, etc., will be used.
The degradation process
Once collected, these materials are placed in a digester where they are degraded by microorganisms (different bacteria) and in the absence of oxygen.
Biogas and digestate production
The result of this process is the production:
- of biogas, which can be used as a source of renewable energy and as fuel for cars,
- and of digestate, a natural fertilizer rich in nutrients.
The advantages of agricultural anaerobic digestion
Agricultural anaerobic digestion offers a multitude of advantages that make it attractive to farmers and society.
Environmental advantages
Agricultural anaerobic digestion helps reduce greenhouse gas emissions by producing biogas that can be converted into electricity and/or heat, or injected into the natural gas network. This "biomethane" or "green gas" then replaces fossil fuels. Agricultural anaerobic digestion also allows the treatment of biodegradable waste, which is then transformed into digestate. In the case of the treatment of livestock effluents, digestate offers an interesting alternative to synthetic fertilizers and fertilizers.
Finally, agricultural anaerobic digestion contributes to the circular economy by transforming waste into resources, while creating local jobs.
Economic advantages
Agricultural anaerobic digestion also offers economic advantages, such as the creation of additional income for farmers through the sale of biogas and digestate.
The challenges of anaerobic digestion
Agricultural anaerobic digestion faces various challenges that can hinder its development. These challenges can be technical and operational and include the need for significant initial investment, the complexity of managing the anaerobic digestion process, and equipment maintenance. Agricultural anaerobic digestion is also faced with regulatory and administrative obstacles, such as obtaining the necessary permits and complying with environmental standards.
In short, agricultural anaerobic digestion is a promising process that offers environmental, economic, and societal advantages. However, it is essential to overcome the technical, operational, and regulatory challenges to fully realize its potential.
A practice strongly supported by the actors of the Sommet de l’Élevage, agricultural anaerobic digestion is a solid foundation supporting the ambitions of a more sustainable agriculture. The event highlights this ecological solution through its program by organizing several interventions and conferences on this topic.
During the 4 days of the Summit, you will be able to attend no less than 8 presentations on agricultural anaerobic digestion with feedback from experience and assistance for farmers wishing to set up their anaerobic digestion project.