Biogas digester is made of steel plates produced of steel with high quality coating made according to technology of high-temperature sintering "elamel". Such coating has long lifetime and is resistant to chemical exposure, corrosion and is impact-resistant. Such structure can be quickly mounted. Advantage of steel tanks if compared to concrete tanks is that they have long lifetime, do not need falsework during the installation, quick installation, and possibility of construction at any time of the year. Also one of advantages of steel tanks is that it can be quickly dismantled and is considered as a good mortgage by the bank.

When digester is made of steel plates round shaped concrete bottom for steel tank mounting must be prepared before the installation. Steel plates are covered with several layers of special anticorrosive enamel, which ensures long lifetime of the tank. All embedded parts, manholes, mixers holes are produced according to the system peculiarities. Digester bottom has 2% inclination to the center for better mixing and substrate discharge. For complete discharge of substrate digester bottom is equipped with discharge pipe. Heating system is mounted on digester walls in order to ensure biomass heating to 34-37°С and secure mesophilic digestion mode. Outside digester wall is heat insulated with the blocks made of extruded foamed polystyrene, which allows heat saving and reduces heat power consumption for digester heating. Underground part of the digester bottom or wall has hydro insulation. Heat insulation of the external side of the digester wall is protected from the mechanical damages with the help of profiled steel sheets.