Effects of Exogenous Biochar Addition on High Solid Anaerobic Fermentation of Livestock Manure for Environmental Pollution Control

In order to explore the effects of adding biochar on biogas production by high solid concentration anaerobic fermentation of livestock and poultry manure and agricultural safety, this study used pig manure, cow manure and chicken manure as fermentation raw materials, and carried out experiments on biogas production by mesophilic temperature anaerobic fermentation with high solid concentration. The changes of cumulative biogas production, biogas production rate, methane (CH₄) content, volatile fatty acid (VFA) and hydrogen sulfide (H₂S) content in three kinds of livestock manure with or without biochar were analyzed. The results showed that the addition of biochar had different effects on anaerobic fermentation of livestock and poultry manure with high solid concentration, increased the content of CH4 and decreased the content of H₂S. the addition of biochar provided enough granular surface to absorb a large number of inoculated microorganisms, which shortened the start-up time, increased the biogas production rate of high-solid anaerobic fermentation of livestock and poultry manure, and advanced the peak period of biogas production; reduced the content of VFA, reduced the inhibition of methanogens, so the methane content increased. The addition of biochar had the most obvious effect on anaerobic fermentation of cow manure and chicken manure with high solid content.