A comprehensive review on current trends and development of biomethane production from food waste: Circular economy and techno economic analysis

Biogas production from food waste with anaerobic digestion process and co-digestion process obtained high purity of biogas. Food waste consists of proteins, carbohydrates, inorganic compounds, fibre, sugars, and lipids. Fossil fuels have caused some environmental and human health problems, such as effects of global warming, greenhouse gas emissions. Biogas production is a simple process and is purified into methane and used in many applications, heat, electricity and vehicle fuel. Different types of food waste are collected and processed into biogas, which is essential for human use and as an alternative to fossil fuels. The collection of food waste, pretreatment process, production of biogas, purification of biogas, upgradation of biomethane, and circular bioeconomy are clearly explained. Anaerobic digestion and co-digestion processes have increased biomethane yield, up gradation and purification of biogas have also been discussed. Five different types of upgradation processes are included, such as physical scrubbing, chemical scrubbing, pressure swing adsorption, membrane separation, and cryogenic separation. The upgradation process and the purity level also mentioned in this review, it represents the biomethane quality. Techno economic effects and circular bioeconomy levels are addressed in this review. Life cycle assessment, life cycle impact analysis and environmental impact level are discussed. However, Challenges and future perspectives of biogas production and to improve the biomethane purity level. 89% of the biogas production is obtained from fruit waste with anaerobic digestion, after the upgradation process, 99% purity of biomethane is separated.