Published:01 Jul 2013
It has been estimated by the World Bank that at least 1.3 billion tonnes (Gt) of municipal solid waste is currently produced across the world each year and this is expected to rise to 2.2 Gt by 2025. There is an urgent need to recover value from this waste rather than commit it to landfill or other disposal methods. Even greater quantities of waste are generated by manufacturing, construction and mining industries and global concerns over the decline of the planet's finite natural resources have seen a change of emphasis towards resource recovery through re‐use, recovery and recycling of wastes. This book brings together a group of experts involved in the various aspects of waste management to give a wide‐ranging overview of the problems that need to be addressed in achieving greater efficiencies in resource recovery from waste and the potential solutions to these problems.
The first of the nine chapters in this book is written by Chunfei Wu and Paul Williams of the University of Leeds Energy Research Institute. This chapter reviews the range of advanced thermal technologies of pyrolysis and gasification that provide significant economic and environmental options for converting waste materials into useful and high‐value materials, fuels and chemicals. In Chapter 2, Richard Shaw and colleagues from the British Geological Survey address the problem of resource recovery from mine waste. A series of case studies focus on the recovery of high‐value metals from waste streams, illustrating the various technological, economic and environmental factors that influence the scale of recovery. Chapter 3, by James Clark and Avtar Matharu of the University of York's Green Chemistry Centre of Excellence, provides a holistic overview of global waste, focusing on the food supply chain and electrical and electronic equipment as sources of resource‐important waste. Food waste is shown to be capable of yielding fuels and chemicals and a wide range of critical elements, such as indium, are being recovered from WEEE. The range of plastics used in packaging, from PET bottles to PS containers, is then reviewed in Chapter 4 by Karl Williams of the Centre for Waste Management at the University of Central Lancashire. The emphasis here is on viewing plastic packaging as a recoverable resource and the roles played by policy measures and legislation, as well as by technology in its collection and reprocessing, are described.
A quite different but equally concerning issue in waste management is the depletion of non‐renewable mineral fertilisers that are essential to agriculture and food production. For example, there are growing concerns that the global production of phosphate rock will become insufficient to satisfy demand in the foreseeable future and its essential and non‐substitutable nature is driving efforts to recycle phosphorus from waste streams such as wastewater and sewage sludge. This issue is explored in Chapter 5 by Sebastian Petzel of BASF and Peter Cornel of the Technical University of Darmstadt, Germany, through their detailed examination of phosphorus recovery from wastewater.
The Chinese perspective on waste as a resource is provided in Chapter 6 by He Pinjing and colleagues from Tongji University in Shanghai. They describe recent developments in the area, with particular reference to the circular economy as a guiding principle. This encompasses concepts such as ‘cradle‐to‐cradle’ and remanufacturing in its approach to establishing a resource‐secure economy. The chapter presents examples of recent successful practices which illustrate the technical and economic viability of using waste as a resource, with examples drawn not only from China but also from countries of the European Union, the United States and Japan. The Japanese situation is further elaborated by Yashiko Hotta of the Institute for Global Environmental Strategies in Kanagawa, Japan, who devotes Chapter 7 to a discussion of recycling policy based on the ‘sound material cycle society’ and ‘3R’ (reduce, re‐use, recycle) concepts in Japan and other Asian countries. The emphasis here is on the policy‐related organisation of institutional infrastructures needed to sustain recycling mechanisms rather than on technical solutions or engineering of resource recovery from waste.
Chapter 8, by Ed Stentiford of the University of Leeds, is concerned with composting and compost. This looks at the fundamental processes that drive composting and the key features needed for the delivery of a quality product. The biological degradation process is analysed in detail, with particular attention to factors controlling the reaction rate. The related biodegradation processes that occur in landfill that contains municipal solid waste are discussed in the final chapter, by Geoff Watson and William Powrie of the University of Southampton. Their emphasis is on the UK but the discussion is relevant to all developed countries where attention is shifting from waste disposal to resource management. A modern landfill is required to prevent environmental pollution through the leakage of leachate into groundwater and the emission of fugitive degradation gases to the atmosphere. The engineered containment features needed to achieve this are described, as are the prospects for mining of older landfills to extract minerals or other valuable materials. Recovery of leachate and of energy from biogas are important features of a modern landfill.
We believe this book will be found interesting and useful by all concerned about the ever‐growing volume of waste generated by both developed and developing societies and wishing to know what can be done to minimise waste and to recover value from it. In particular, we commend it to policy makers, teachers and students in science and engineering programmes and resource management courses, and those engaged in the water, mining and agricultural industries.