This book presents a Two-Stage Anaerobic Digestion (TSAD) technique for producing hydrogen and methane, following a step-by-step approach in order to guide readers through the experimental verification of the related hypothesis. In the first stage of AD, the reaction conditions are optimized to obtain the maximum amount of hydrogen, while in the second the liquid residue from the first phase is used as a substrate to produce fuel-methane. AD has traditionally been used to reduce the organic content of waste; this results in a biogas that is primarily constituted of CH4 and CO2. Over the last few decades, the conversion of organic matter into hydrogen by means of AD and selecting Hydrogen Producing Bacteria (HPB) has matured into a viable and sustainable technology among the pallet of H2 generation technologies. The combined bio-production of hydrogen and methane from Organic Waste Materials (OWM) is considered to be an ideal way of utilizing waste, and can increase energy efficiency (the substrate Heat Value converted into H2 and CH4 fuel) to roughly 80%, since the energy efficiency of H2-production alone (15%) is not energetically competitive. The two gas streams can be used either separately or in combination (Hytane®), be supplied as civilian gas or used for transportation purposes. All the aspects of this sustainable technology are taken into account, from the basic biochemical implications to engineering aspects, establishing the design criteria and the scale-up procedures for full-scale application. The sustainability of the TSAD method is assessed by applying EROI (Energy Return On Investment) and EPT (Energy Payback Time) criteria, and both the general approach and application to the field of Anaerobic Digestion are illustrated.

This book presents a Two-Stage Anaerobic Digestion (TSAD) technique for producing hydrogen and methane, following a step-by-step approach in order to guide readers through the experimental verification of the related hypothesis. In the first stage of AD, the reaction conditions are optimized to obtain the maximum amount of hydrogen, while in the second the liquid residue from the first phase is used as a substrate to produce fuel-methane. AD has traditionally been used to reduce the organic content of waste; this results in a biogas that is primarily constituted of CH4 and CO2. Over the last few decades, the conversion of organic matter into hydrogen by means of AD and selecting Hydrogen Producing Bacteria (HPB) has matured into a viable and sustainable technology among the pallet of H2 generation technologies. The combined bio-production of hydrogen and methane from Organic Waste Materials (OWM) is considered to be an ideal way of utilizing waste, and can increase energy efficiency (the substrate Heat Value converted into H2 and CH4 fuel) to roughly 80%, since the energy efficiency of H2-production alone (15%) is not energetically competitive. The two gas streams can be used either separately or in combination (Hytane®), be supplied as civilian gas or used for transportation purposes. All the aspects of this sustainable technology are taken into account, from the basic biochemical implications to engineering aspects, establishing the design criteria and the scale-up procedures for full-scale application. The sustainability of the TSAD method is assessed by applying EROI (Energy Return On Investment) and EPT (Energy Payback Time) criteria, and both the general approach and application to the field of Anaerobic Digestion are illustrated. .

Anaerobic digestion (AD) is one of the oldest biotechnological processes and originally referred to biomass degradation under anoxic conditions in both natural and engineered systems. It has been used for decades to treat various waste streams and to produce methane-rich biogas as an important energy carrier, and it has become a major player in electrical power production. AD is a popular, mature technology, and our knowledge about the influencing process parameters as well as about the diverse microbial communities involved in the process has increased dramatically over the last few decades. To avoid competition with food and feed production, the AD feedstock spectrum has constantly been extended to waste products either rich in recalcitrant lignocellulose or containing inhibitory substances such as ammonia, which requires application of various pre-treatments or specific management of the microbial resources. Extending the definition of AD, it can also convert gases rich in hydrogen and carbon dioxide into methane that can substitute natural gas, which opens new opportunities by a direct link to traditional petrochemistry. Furthermore, AD can be coupled with emerging biotechnological applications, such as microbial electrochemical technologies or the production of medium-chain fatty acids by anaerobic fermentation. Ultimately, because of the wide range of applications, AD is still a very vital field in science. This Special Issue highlights some key topics of this research field.

Recent advances in technology to recover bioenergy from various feedstocks make them suitable alternatives to fossil fuel. This book contains several scientific discussions regarding microbes involved in biogas production, the anaerobic digestion process, their operation, and application for sustainable development. The book provides in-depth information about anaerobic digestion for researchers and graduate students. The editor sincerely thanks all the contributors, whose efforts have brought this book to fruition.

In recent years, there has been an increase in the concern of society and industries about how food and beverages are produced, the production of natural compounds as well as the concern of industries on fermentation-based processes. Thus, there are several approaches worldwide that are looking for low time and low cost fermentation-based processes integrating not only molecular biology procedures but also engineering. This book contains eleven chapters written by international experts in the field of fermentation. It covers all recent aspects on fermentation-based processes with potential applications in many fields such as bio combustible production, food and beverage processing, and biomedicine.

This book presents the latest advances in and current research perspectives on the field of urban/industrial solid waste recycling for bio-energy and bio-fuel recovery. It chiefly focuses on five main thematic areas, namely bioreactor landfills coupled with energy and nutrient recovery; microbial insights into anaerobic digestion; greenhouse emission assessment; pyrolysis techniques for special waste treatment; and industrial waste stabilization options. In addition, it compiles the results of case studies and solid waste management perspectives from different countries.