Enhancing microbial viability with biochar for increased methane production during the anaerobic digestion of chicken manure

Abstract

This investigation explores the effects of integrating acid-alkali treated biochar into the anaerobic digestion of chicken manure. Digesters containing chicken manure with biochar addition exhibited an 8.4-fold improvement in methane production compared to untreated digesters. In addition, the porous structure of the biochar promoted microbial acclimation, facilitated direct interspecies electron transfer, and provided anchoring points for immobilisation. Anaerobic digesters containing chicken manure amended with biochar also demonstrated increased chemical oxygen demand removal, up to 81.8 %, and maintained lower total ammonia concentrations (2,478 mg/L) compared to levels in control reactors (4418 mg/L). In terms of the microbial community, the addition of propidium monoazide minimised errors in live microbial population estimation, providing new insights into the capacity of biochar to shield microbes from ammonia stress. These findings highlight biochar's quantitative benefits, emphasising its potential in enhancing methane production, mitigating ammonia stress, and promoting microbial resilience in anaerobic digestion.