10 things you should know about methanization

The circular economy is at the heart of Tereos’ production activity and one of its major commitments is to recycle effluents (wastewater or liquid waste). Accordingly, the Group employs methanization, a technology that allows it to recycle its effluents, in particular to produce biogas. Let’s take a closer look at this process that contributes to the development of renewable energies.

1. Methanization is a biological process based on the decomposition of organic matter by bacteria (or micro-organisms). This reaction mainly produces biogas, a water-saturated gas mixture with significant energy potential.
2. In industrial methanization, 60-70% of the organic matter is transformed into methane (CH4), the main component of biogas, while the remainder is mainly made up of CO₂ and water. The optimal reaction is achieved in a zero-oxygen environment, at a temperature of 37°C (close to that of the human body), and with a neutral pH.
3. Any potentially biodegradable effluent or waste can be placed in a “methanizer” to produce biogas. This technology is particularly used in the agricultural industry, with four sectors in total using the technique on its effluents, namely the farming, industrial, household waste, and wastewater treatment plant sectors.
4. This energy is local and renewable. It can be used to generate electricity through a cogeneration motor and to produce heat (only via a boiler). It can also be used to produce fuel for vehicles or be fed into the natural gas network after thorough purification. Tereos recycles biogas in order to generate energy for its own sites by incorporating it into its boilers after it has undergone specific treatment essential to preventing corrosion of the equipment and to ensuring it meets atmospheric emission standards.
5. Methanization facilitates energy transition as it produces biogas that can regularly be used instead of fossil fuels, such as gasoline, natural gas, fuel oil, or coal, thereby reducing greenhouse gas emissions.
6. There are two main techniques used in methanization. One of these focuses on the treatment of effluents, which allows biogas to be created in methanizers before the cleaned water is released into natural waterways. The other process produces a leftover material called the “digestate” in addition to making gas. Tereos uses both of these technologies, but the latter is used more frequently due to the fact that it produces a digestate with attractive agronomic properties that can be used in particular as a fertilizer to replace chemical fertilizers.
7. Tereos’ sites in Artenay (France) and Dobrovice (Czech Republic) have installed “methanizers” to produce vinasse fertilizer. It is a byproduct of the production of alcohol from Tereos sugar beet and is converted into biogas. The methanizers cover a large portion of the distilleries’ energy needs during harvest.
8. In 2017, Tereos, Nestlé, and Bonduelle joined forces to create an industrial consortium aimed at supplying the Vol-V Group’s new methanization plant in the Somme, France with raw materials. Tereos can therefore recycle its waste produce in the form of biogas or agricultural spreading distributed across land belonging to the growers involved in this project.
9. In France, three Tereos sites are involved in methanizing effluents at their wastewater treatment plants: Origny, Lillers, and Lillebonne. The Belgian site in Aalst also uses this technology to produce biogas and to purify the effluents derived from the process before releasing them into the natural environment. The Ceské Mezirici and Dobrovice sites in the Czech Republic, TSSI Redwood in Indonesia, Teiling and Dongguan in China, and TSSB Palmital in Brazil also use this technology
10. Methanization technologies can vary and differ depending on geographical location and the amount of land available. In early 2017, Tereos launched a “methanization lagoon” project in Brazil at its Palmital site. This corn starch facility boasts large reservoirs where it can treat its effluents under the high outdoor temperatures, producing biogas in the process. To make a comparison, the methanizer at the Origny site is able to treat approximately the same weight of organic pollution over an area fifteen times smaller.