Analysis of the criteria for improving biogas production: focus on anaerobic digestion

The recovery of energy potential through anaerobic digestion is a widely used method for treating biodegradable waste. However, challenges related to operational issues, waste characterization, and process instability hinder its widespread application and result in low methane yields. This review aims to organize and analyze the static and dynamic parameters that influence biogas yield in order to optimize its production. Biogas typically consists of 50–70% methane (CH 4 ) and 30–50% carbon dioxide (CO 2 ) along with traces of other gases. The paper highlights various solutions to enhance CH 4 production, including substrate pre-treatment, co-digestion, Fe 0 powder addition, anaerobic fungi, multi-stage biodigester design, and controlling factors influencing anaerobic digestion. These factors primarily include methanogenic potential, C/N ratio, digestion temperature, pH, reactor tightness, and Pressure. However, the use of bioreactors faces technical, socio-economic, and environmental constraints that vary between developed and less developed countries, as discussed in the paper. Through an analysis of over 30 substrate types, the optimum ratios for certain substrates to achieve higher biogas yields were identified. For cow manure mixed with other materials, the yield increases within a C/N ratio of 20–30 and decreases at a ratio of 35. In the case of poultry droppings mixed with other substrates, the yield increases within a C/N ratio of 18–22. Food waste yield, on the other hand, varies significantly due to the differing characteristics of food waste sources. In summary, this study emphasizes the importance of optimizing biogas production through understanding and controlling the influencing factors. It provides insights into potential solutions and optimum substrate ratios for improved biogas yield. Graphical abstract