Anaerobic Digestion Of Solid Waste And Sewage Sludge To Methane

Biomethanization of the Organic Fraction of Municipal Solid Wastes is a comprehensive introduction to both the fundamentals and the more practical aspects of the anaerobic digestion of organic solid wastes, particularly those derived from households, that is, the organic fraction of municipal solid wastes (OFMSW). It can be used as a textbook for specialized courses and also as a guide for practitioners. In the first part, the book covers the relevant aspects of anaerobic digestion (AD) of organic wastes. The fundamentals and kinetic aspects of AD are reviewed with particular emphasis on the aspects related to solid wastes. This introduction is necessary to have a comprehensive view of the AD process and to understand the practical principles as well as the origin of possible problems arising from the management of the process. Chapter 2 emphasizes the role of kinetics in designing the reactor, paying special attention to existing models, particularly the dynamic ones. Through this introduction, it is intended to facilitate the technology transfer from laboratory or pilot plant experiences to full-scale process, in order to implement improvements in current digesters. Laboratory methods are described for the analysis and optimization of reactor performance, such as methanogenic activity tests or experimental evaluation of the biodegradation kinetics of solid organic waste. The different reaction patterns applied to industrial reactors are outlined. Industrial reactors are classified in accordance with the system they use, pointing out advantages and limitations. Co-digestion, enabling the co-treatment of organic wastes of different origin in a more economically feasible way, is described in detail. Examples of co-digestion are given, with OFMSW as a base-substrate. Finally, full-scale co-digestion plants are discussed. Various types (mechanical, biological, physico-chemical) of pre-treatment to increase the biodegradability, and thus the yields of the process, are reviewed in detail. The use of the fermentation products of anaerobic digesters for biological nutrient removal processes in wastewater treatment plants is described. This constitutes an example of integrated waste management, a field in which both economic and technical advances can be achieved. Balances are given to justify the approach, and a full-scale case study is presented. The important topic of economics and the ecological advantages of the process are emphasized. The use of compost, the integration with composting technology, and advantages over other technologies are detailed in the framework of an environmental impact assessment of biowaste treatment. Finally, the anaerobic digestion of MSW in landfills is reviewed in detail, with emphasis on landfill process enhancement and strategies for its application.

This volume in the Energy from Wastes Series covers the area of methane production from agricultural and domestic wastes. Principally this involves the conversion of excreta and other organic effluents to a valuable gaseous fuel plus, in many cases, a useful sludge for fertiliser or feedstuffs. Dr Hobson and his colleagues have written a comprehensive text on the principles of microbiological processes and the biochemistry of anaerobic digestion, embracing the design of digesters with examples of current working installations. The potential for anaerobic digestion of wastes as diverse as sewage to fruit processing effluents is also reviewed. This work should be of interest to all who have to manage organic waste treatment and disposal, as well as to a wider readership who wish to know more about methane production by anaerobic digestion. ANDREW PORTEOUS v Preface The production of methane, or more exactly, a flammable 'biogas' containing methane and carbon dioxide, by microbiological methods ('anaerobic digestion') is not new. The reactions have been in industrial use for over a hundred years, but only in sewage purification processes. In some times of national stress, such as war-time, the microbiological production of gas purely for fuel has been investigated, but with the resumption of plentiful su pplies of fossil fuels the investigations have faded awa y.

It is hoped that this book will promote an appreciation of the environmental problems, energy demand and resources, the economics and risks involved that are essential to define the role of waste-to-energy systems in the future.

Anaerobic digestion (AD) is a biological process that happens naturally when bacteria breaks down organic matter in environments with little or no oxygen. It is effectively a controlled and enclosed version of the anaerobic breakdown of organic waste in landfills which release methane. In this book, the authors present current research in the study of the processes, products and application of anaerobic activity. Topics discussed include the anaerobic treatment of wastewater; a scientific review of the agronomic, environmental and social benefits of anaerobic digestion and the microbial aspects of anaerobic digestion for biogas production.