1
1
Introduction
M. Balakrishnan, V.S. Batra,
J.S.J.Hargreaves, and I.D. Pulford
Recently, concern about the fate of waste products produced by a whole range of
industrial processes has combined with a growing realization that they may have
potential uses and, therefore, value (Balakrishnan etal., 2011; Gupta etal., 2009).
This has led to a large number of studies aimed at utilizing such wastes, which is
the focus of this book. The following chapters discuss various selected classes of
large-scale waste and their current applications and potential future applications.
Chapter 2 details different wastes derived from metal processing. In Chapter 3,
combustion products are discussed; here, the focus is on coal combustion products
given the widespread use of coal. Chapter 4 details waste electrical and electronic
equipment (WEEE) and Chapter 5 discusses food waste. Before discussing eachof
these classes, it is important to make a number of general considerations.
CONTENTS
1.1 Drivers for Waste Recovery and Reuse ............................................................2
1.1.1 Problems of Disposal of Large Amounts of Waste ..............................2
1.1.2 Environmental Issues ............................................................................3
1.1.3 Resource Recovery ...............................................................................3
1.1.4 Economics.............................................................................................6
1.1.5 Legislation ............................................................................................6
1.2 Types of Waste ..................................................................................................8
1.3 Secondary Processes ........................................................................................9
1.3.1 Catalysis ................................................................................................9
1.3.2 Energy Production .............................................................................. 10
1.3.3 Agricultural ........................................................................................10
1.3.4 Environmental Clean-Up .................................................................... 11
1.4 Secondary Products ........................................................................................ 12
1.4.1 Cement, Concrete, and Ceramics .......................................................12
1.4.2 Chemicals ...........................................................................................13
1.4.3 Composts ............................................................................................13
1.4.4 Metal Recovery ...................................................................................13
1.5 Conclusion ...................................................................................................... 13
References ................................................................................................................13
2 Conversion of Large Scale Wastes into Value-added Products
1.1 DRIVERS FOR WASTE RECOVERY AND REUSE
A number of factors combine to act as drivers for waste recovery and reuse:
1. Problems of disposal of large amounts of waste
2. Environmental issues
3. Availability of resources
4. Economics
5. Legislation
The focus widens going down this list, from aspects that affect mainly the
producers of the waste to ones affecting the whole community. The environmental
and economic issues drove the political requirements that most developed, and
increasingly less-developed, countries have now translated into legislation.
1.1.1 Problems of DisPosal of large amounts of Waste
Some industries produce very large amounts of waste. For example, global y ash
production from coal combustion (Chapter 3) is estimated to be of the order of 500
million tonnes/year, while slag from iron and steel production and red mud from
production of aluminium (Chapter 2) both generate about 100 million tonnes/year.
(Rounded gures are used here; see individual chapters for more detail). As these
are continuous processes, the wastes must be removed from the systems in order for
them to function efciently. Traditionally, such wastes have been dumped in heaps
or lagoons, which can become extensive as more wastes are produced. The disposal
sites also have to be close to the source of the waste (blast furnace, power station,
etc.) in order to reduce transportation costs. As a result, large areas adjacent to such
facilities can be given over to disposal and storage of waste.
Waste from various food producing processes can also be signicant (Chapter 5).
For example, approximately 60 to 70 million tonnes of both rice husk and orange
peel are produced annually. Again, such waste is produced locally where foodstuffs
are processed. For example, it is estimated that 2.5 to 4.0 million tonnes of olive oil
processing waste are produced annually in the Andalusia region of Spain alone.
Over recent years, WEEE (Chapter 4) has become signicant, with an estimated
annual production of 20 to 25 million tonnes. Much of the material that goes into
this waste stream is bulky (refrigerators, television sets, etc.), which causes particular
storage problems.
In addition to the availability of land on which to store wastes, the main issues that
also need to be considered are safety and toxicity. Storage of large volumes of waste
presents the problem of physical containment. In some cases, the waste may contain
toxic components, whose dispersal into the wider environment could be detrimental
to human health and the ecology of the local area. There have been a number of
high-prole incidents over recent years where failure of the waste containment system
has led to fatalities, poisoning of humans, and contamination of land and water.
Selected recent incidents taken from a list of major tailings dam failures spanning the
previous 50+ years published on the Web (http://www.wise-uranium.org/mdaf.html)

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