- a reception area
- a digester (or fermentation tank)
- a gas holder
The reception area is where the raw materials arrive and are prepared for anaerobic digestion. Each type of biomass has a different fermentation process, so the overall length of the biogas production process varies depending on the raw materials used, and it isn’t uncommon to use pre-treatments in industrial biogas plants to accelerate fermentation and increase the production of biogas. Some of the most popular biomass choices are crop residues, municipal and industrial sewage, agricultural material, livestock manures, seaweed, food processing, and paper wastes, but the list of raw materials used is significantly longer. The digester is an air-tight, waterproof container with a means of entry for biomass. Here, you introduce the raw materials to be transformed into energy. Then, agitators shift the biomass periodically to free the gases and prevent the formation of layers. The digester also includes a pipe that enables the digestate to be removed after the fermentation is over. The gas holder is an airproof container, preferably made of steel, that collects the gas generated during fermentation. It’s provided with a gas outlet that permits the biogas to come out of the system and produce energy and heat. Depending on the quantity of waste you want to eliminate from the environment or the volume of biogas you need to produce, a plant might have more than one digester and gas holder.