The study investigates the integration of acid-alkali treated biochar in the anaerobic digestion of chicken manure, revealing significant enhancements in methane production and chemical oxygen demand removal. Utilizing biochar as an additive in digesters led to an 8.4-fold increase in methane output compared to control digesters without biochar. This substantial improvement is attributed to biochar’s porous structure, which supports microbial acclimation, facilitates direct interspecies electron transfer, and provides anchoring points for microbial immobilization. Moreover, reactors with biochar showed a notable increase in chemical oxygen demand removal efficiency, reaching up to 81.8%, and maintained total ammonia nitrogen concentrations well below the levels that could inhibit the process, thereby underscoring biochar’s potential in mitigating ammonia stress on microbes.

The study also highlights the innovative use of propidium monoazide to minimize errors in estimating live microbial populations, offering new insights into biochar’s role in protecting microbes from ammonia-induced stress and enhancing their viability. This approach has unraveled biochar’s qualitative benefits, further emphasizing its capability to improve methane production, alleviate ammonia stress, and bolster microbial resilience in anaerobic digestion systems.

Given the intensive global poultry farming, which results in significant quantities of chicken manure, the findings of this study are particularly relevant. Anaerobic digestion presents a viable solution to managing this waste while producing renewable energy. However, challenges such as ammonia inhibition have hampered its efficiency. The incorporation of biochar, especially acid-alkali treated, into the digestion process appears to address these challenges effectively, marking a significant advancement in the sustainable management of chicken manure and the optimization of biogas production.