Anaerobic Digestion

Hundreds of million tonnes of agricultural and food waste are produced each year around the world, most of which is just that, waste. Anaerobic digestion, biogas and the heat and electricity that can be produced from it is still a nascent industry in many countries, yet the benefits of AD spread throughout the community: Gives good financial returns to farmers and eco-entrepreneurs. Helps community leaders meet various policies and legislative targets. Offers an environmentally sensitive waste disposal option. Provides a local heat and power supply, & creates employment opportunities Reduces greenhouse gas emissions, as well as providing an organic fertilizer. Although the process of AD itself is relatively simple there are several system options available to meet the demands of different feedstocks. This book describes, in simple, easy to read language the five common systems of AD; how they work, the impact of scale, the basic requirements, the costs and financial implications, and how to get involved in this rapidly growing green industry.

Anaerobic digestion is a biochemical degradation process that converts complex organic material, such as animal manure, into methane and other byproducts. Part of the author's Wastewater Microbiology series, Microbiology of Anareboic Digesters eschews technical jargon to deliver a practical, how-to guide for wastewater plant operators.

This book presents new application processes in the context of anaerobic digestion (AD), such as phosphorus recovery, microbial fuel cells (MFCs), and seaweed digestion. In addition, it introduces a new technique for the modeling and optimization of AD processes. Chapters 1 and 2 review AD as a technique for converting a range of organic wastes into biogas, while Chapter 3 discusses the recovery of phosphorus from anaerobically digested liquor. Chapters 4 and 5 focus on new techniques for modeling and optimizing AD. Chapters 6 and 7 then describe the state of the art in AD effluent treatment. The book’s final three chapters focus on more recent developments, including microbial fuel cells (MFCs) (Chapter 8), seaweed production (Chapter 9), and enzyme technologies (Chapter 10).

Anaerobic digestion is used for industrial or domestic purposes to manage waste and/or to produce fuels. Anaerobic digestion are the group of processes by which micro-organisms break down biodegradable material in the absence of oxygen. In this book, the authors present current research in the study of the types, processes and environmental impact of anaerobic digestion. Topics include the development and application of anaerobic digestion to treat husbandry and industrial wastewater in the Mekong Delta of Vietnam; anaerobic digestion of agricultural waste; evaluation of decentralised anaerobic digestion systems for wastewater treatment, reuse and nutrient recycling to alleviate water and food stress; effects of substrate-to-inoculum ratio on anaerobic digestion of vegetable wastes; anaerobic digestion sustainability effects on plant-wide performance and automation in centralised wastewater treatment; and anaerobic co-digestion of cheese whey and the screened liquid fraction of dairy manure.

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 of biomass to biogas, commonly occurring in natural anoxic ecosystems, is an excellent method for utilizing wastes and producing green energy. This book presents examples of local installations of AD, or their proposals, located at small factories, workplaces, and in rural areas and housing complexes. The facilities consider the specific nature of the region, site conditions, and specificity of the utilized wastes. They protect the environment and ensure dispersed energy production. The latter is of great economic significance due to its closeness to end customers. Small local installations expand the pool of renewable energy on a global scale.

Biogas Production covers the most cutting-edge pretreatment processes being used and studied today for the production of biogas. As an increasingly important piece of the "energy pie," biogas and other biofuels are being used more and more around the world in every conceivable area of industry and could be a partial answer to the energy problem and the elimination of global warming. This book will highlight the recent advances in the pretreatment and value addition of lignocellulosic wastes (LCW) with the main focus on domestic and agro-industrial residues. Mechanical, physical, and biological treatment systems are brought into perspective. The main value-added products from lignocellulosic wastes are summarized in a manner that pinpoints the most recent trends and the future directions. Physico-chemical and biological treatment systems seem to be the most favored options while biofuels, biodegradable composites, and biosorbents production paint a bright picture of the current and future bio-based products. Engineered microbes seem to tackle the problem of bioconversion of substrates that are otherwise nonconvertible by conventional wild strains. Although the main challenge facing LCW utilization is the high costs involved in treatment and production processes, some recent affordable processes with promising results have been proposed. Future trends are being directed to nanobiotechnology and genetic engineering for improved processes and products.

There have been many significant microbiological, biochemical and technological advances made in the understanding and implementation of anaerobic digestion processes with respect to industrial and domestic wastewater treatment. Elucida tion of the mechanisms of anaerobic degradation has permitted a greater control over the biological parameters of waste conversion and the technical advances achieved have reduced the time and land area requirements and increased the cost-effectiveness and efficiency of the various processes presently in use. By product recovery in the form of utilisable methane gas has become increasingly feasible, while the development of new and superior anaerobic reactor designs with increased tolerance to toxic and shock loadings of concentrated effiuents has established a potential for treating many extremely recalcitrant industrial wastestreams. The major anaerobic bioreactor systems and their applications and limitations are examined here, together with microbiological and biochemical aspects of anaerobic wastewater treatment processes. London, June 1986 S. M. Stronach T. Rudd J. N. Lester v Table of Contents 1 The Biochemistry of Anaerobic Digestion 1 1. 1 Kinetics of Substrate Utilisation and Bacterial Growth 3 1. 1. 1 COD Fluxes and Mean Carbon Oxidation State 3 1. 1. 2 Bacterial Growth and Biokinetics 4 1. 1. 2. 1 Growth and Single Substrate Kinetics 4 1. 1. 2. 2 Multisubstrate Systems . 8 1. 2 Kinetics and Biochemistry of Hydrolysis 8 1. 3 Kinetics and Biochemistry of Fermentation and J1-0xidation . 11 1.