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Dry fermentation of biogas refers to a fermentation process in which organic waste such as straw and livestock manure (with a dry matter concentration of over 20%) is used as raw material, and anaerobic bacteria are employed to break it down into gases such as CH4, CO2, and H2S. Some people call dry fermentation solid fermentation or high-concentration fermentation. Due to the excessively high solid concentration, it is difficult to use continuous or semi-continuous feeding methods; therefore, batch feeding is used in the vast majority of cases. A notable feature of dry fermentation is the high total solid content of the fermentation substrate; it proceeds at a relatively high level of volatile acids, and the key to this process lies in preventing the excessive accumulation of organic acids. Disadvantages: Dry fermentation faces technical challenges such as difficulties in feeding and discharging materials, uneven heat and mass transfer, and acidosis, due to the high dry matter concentration of the fermentation substrate. Advantages: It has a high gas production rate per unit volume of the tank, which helps to reduce the investment required for building such tanks; moreover, the structure of the fermentation tank is simple, making feeding, discharging, and maintenance tasks easier and safer. By conserving water, and considering that biogas slurry is of high quality in small quantities and easy to transport, which saves transportation labor, it is therefore highly suitable for widespread use as fertilizer in rural areas in the north and arid regions. Dry biogas fermentation technologies abroad are already mature. Large-scale dry biogas fermentation systems such as garage-type dry fermentation systems, gas-bag type dry fermentation systems, combined dry-wet fermentation systems, and leachate storage tank type dry fermentation systems have been put into practical use, enabling large-scale biogas production.