Biogas Production From Chicken Litter: Advances, Challenges, and Perspectives of Anaerobic Digestion

Anaerobic digestion stands out as a promising technology for the energy valorization of chicken litter, yielding both biogas and digestate. This study presents a systematic bibliometric review using the Methodi Ordinatio 2.0 methodology to identify global research trends, scientific gaps, and technological advances related to biogas production from chicken litter through anaerobic digestion. A literature search yielded 112 articles from the Scopus database, resulting—after analysis—in a final portfolio of 101 peer-reviewed scientific articles selected based on bibliometric criteria, including journal impact, citation count, and year of publication. The results indicate that the main challenges associated with the anaerobic digestion of chicken litter include its high nitrogen content, low carbon-to-nitrogen ratio, ammonia inhibition, and the presence of recalcitrant compounds that reduce biodegradation efficiency and methane yield. To overcome these limitations, several strategies have been proposed, including co-digestion with carbon-rich substrates, physical, chemical, and biological pretreatments, biochar supplementation, microaeration, high-solids anaerobic digestion, and improved operational control. The agricultural application of digestate contributes to nutrient recycling, improved soil fertility, and reduced dependence on synthetic fertilizers, reinforcing circular economy principles. Therefore, the use of chicken litter for biogas production is a promising alternative, with the potential to contribute significantly to environmental sustainability, renewable energy generation and support the long-term development of the poultry sector.