Sustainable biomethane production from waste biomass: challenges associated with process optimization in improving the yield

Various novel technologies are currently under development aimed at improving bio-methane output to tackle challenges related to process stability, biogas production, and methane quality in the anaerobic digestion (AD) process. The management of substrate type, temperature, pH, hydraulic retention time (HRT), organic loading rate (OLR), and inoculum origin is essential for ensuring process effectiveness, minimizing inhibition, and maximizing production of biogas and methane yield. The review emphasizes sustainability, focusing on the environmental and economic benefits of anaerobic digestion, including the reduction of greenhouse gas (GHG) emissions, the minimization of landfill waste, and the provision of renewable energy sources. The range of process of variables such as carbon-nitrogen (C:N) ratio (13.6-32.5), temperature (30-56 °C), pH (6-8.5), HRT (3-30 days), and OLR (1-10 g VS m³ day^-1) were discussed. The review examined recent technologies and innovative methods that improve the productivity of anaerobic digestion, increase biogas output, and advance process management. Several obstacles remain to be addressed, including substrate availability and quality, management of process parameters, and the handling of digestate for sustainable bio-methane production. The final section of the review emphasizes the necessity to optimize process parameters, ensure sustainability, address existing issues, and initiate further research to improve the performance of the AD process for a more sustainable and circular economy. Anaerobic digestion has the potential to significantly contribute to climate change mitigation, waste elimination, and the provision of a sustainable energy source for the future.