Effect of Peanut Straw Biochar on the Co-Digestion Process of Cattle Manure with Corn Stover

Peanut straw, a lignocellulosic agricultural residue rich in cellulose, hemicellulose, and lignin, has significant potential for biochar production, which may enhance the anaerobic digestion (AD) process. The addition of biochar can effectively enhance the AD process. However, the role of peanut straw biochar in anaerobic co-digestion of mixed substrate remains underexplored. This study innovatively employs peanut straw biochar as an exogenous additive in anaerobic co-digestion of cow manure and corn straw. The results demonstrate that the optimal methane yield was achieved at a biochar dosage of 8%, with a significant increase of 19.1% compared to the control group (832.23 mL). Various doses of biochar also facilitated the degradation of the digestion substrate to varying extents, with the highest substrate removal rate of 54.1% achieved when biochar was added at 8%. Furthermore, the addition of peanut straw biochar enhanced the microbial community structure. Specifically, the inclusion of 8% biochar increased the relative abundance of Methanosarcina by 2.8%, while the addition of 6% biochar elevated the relative abundance of Chloroflexota by 1.4%. This study contributes to the sustainable use of agricultural waste and supports the development of biochar-enhanced AD for improved waste management and energy recovery.