A comparative analysis of pre-treatment technologies for enhanced biogas production from anaerobic digestion of lignocellulosic waste

In recent decades, biogas production from anaerobic digestion of organic fractions of municipal solid waste and agricultural residues has emerged as a promising strategy for waste management and renewable energy generation. However, due to the complexity and heterogeneity of these feedstocks, an appropriate pre-treatment is required before anaerobic digestion to maximise biodegradability and enhance biogas production. This is especially true for lignocellulosic biomass, where maximum biogas potential is often difficult to reach due to the presence of a lignin barrier, which is not easily biodegradable. Pre-treatment technologies may significantly increase biogas production, up to 360%, from organic fractions of municipal solid waste and agricultural residues. This paper first provides an overview of the pre-treatment technologies, including mechanical, chemical, biological, thermal, plasma, and combined treatments for a wide variety of feedstocks for biogas production from anaerobic digestion. These studies indicate that the selection of a pre-treatment technology mainly depends on the waste substrate characteristics, the desired end results, and resource availability. Furthermore, most studies emphasise the significance of balancing the benefits and drawbacks of pre-treatment technologies for sustainable waste-to-energy practices. Then, the article evaluates the scalability, technical feasibility, economic viability, industrial applicability and environmental sustainability of appropriate pre-treatment methods. This review will be a valuable resource for researchers, policymakers, and practitioners working in the field of waste-to-energy conversion through anaerobic digestion.