Enhanced methane production during the anaerobic digestion of chicken manure through the addition of pristine and recovered biochar

This study investigates the impact of a 50:50 mixture of pristine and recovered biochar (CBC) on high-solids anaerobic digestion of chicken manure, comparing its performance with pristine biochar (PBC), recovered biochar (RBC), and a Control group. The experiment, conducted under mesophilic conditions using a 15% total solid content and 5% biochar dosage, showed that CBC treatment achieves the highest cumulative biogas production (314 mL g- 1-VS) and the highest cumulative methane production o(112 mL g- 1-VS) over 21 days. Further, digesters containing CBC exhibited the highest rate of COD removal (80.8%), surpassing digesters amended with PBC (71.1%), RBC (69.2%) and Control (57.8%). Although digesters amended with PBC showed a higher TAN adsorption capacity of 48 mg g- 1 compared to the 32 mg g- 1 of CBC, both TAN adsorption and the existing microbial population of 1.2 x 1014 microbes per gram, have allowed CBC to exhibit superior digester performance. These findings offer valuable insights for optimising anaerobic digestion processes and cutting operational costs in waste-to-energy projects incorporating biochar as an additive.