Methods for Enhancing Biogas Production

The concern about using organic waste as a renewable energy source is a critical worldwide issue. In this area, anaerobic digestion (AD) seems to be a promising solution because of the significant reduction of waste quantity and generation of valuable products such as biogas, regarded as being a good energy carrier and digestate with high nutritional potential for agriculture. The current trends in AD focus on improving the efficiency of the process to make this a cost-effective treatment. Depending on the source (agricultural, municipal, or industrial), organic waste varies considering both its composition and structure, and thus the bioaccessibility and biodegradability. Accordingly, materials rich in carbohydrates, proteins, and fats require different operational conditions to overcome technological problems and minimize the risk of disruption or failure of the anaerobic systems. Different strategies can be used to enhance biogas production, including waste pretreatment (physical, chemical, physico-chemical, biological, and combined), two-stage AD (temperaturephased AD and two-phase AD), anaerobic co-digestion (two-substrate and multi-substrate systems), and bioaugmentation (with natural strains or specialized consortia of microorganisms and genetically modified microorganisms or their consortia). Some of them enhance its accessibility and digestibility, while others improve nutritional balance, metabolic properties, and operational factors, facilitating synergistic effect of microorganisms. This book covers the current developments in the area of enhancing biogas production.