Factors Influencing Biochar-Strengthened Anaerobic Digestion of Cow Manure

Biochar shows great potential for enhancing anaerobic digestion (AD); however, the key factors for this remain unknown. This study evaluated the effects of pyrolysis temperature, porosity, and specific surface area (SSA) on the performance enhancement of biochar. The results showed that pyrolysis temperature played an essential role in enhancing the performance of biochar. The addition of cow manure biochar pyrolyzed at 400 °C (NFC-400) and mushroom bran biochar pyrolyzed at 550 °C (JKC-550) increased methane production by 81.30% and 77.59%, respectively, compared with that by the control. Therefore, NFC-400 showed increased gas production, while JKC-550 showed a shorter fermentation period. The SSA and porosity of biochar positively correlated with the pyrolysis temperature but not with biogas production, which indicated that their influence on AD performance enhancement by biochar was not critical.Graphical Abstract