Page 64 - Materials Chemistry, Second Edition

Chapter 6

Life cycle assessment and waste management

Karli L Verghese

6.1 Introduction
The consumption of products and services fuels the growth of markets and economies around
the world. This growth, however, results in excessive consumption of natural resources and
ever growing volumes of waste, which need to be managed (Hamilton 2003). Waste is gener-
ated from sources as diverse as residential households, offices, manufacturers, building sites,
farms and mining sites. The management of household waste and the example of plastic
shopping bags is the focus of this chapter.
The generation, quantity, type and subsequent management of waste are continual issues
for society. Historically waste has been buried in holes in the ground – out of sight. In recent
decades, the availability of land and ‘holes’ to bury waste has reduced, and the need to address
negative environmental impacts of landfills including leachate and methane generation, and
redirect valuable resources (the waste) back into the economy, have been increasingly recog-
nised. Alternative technologies have been introduced to treat and manage waste, including
reprocessing facilities, composting facilities, waste-to-energy technologies and anaerobic
digestion. The overarching debate is about which technologies and processes are most appro-
priate, and a shift in emphasis has taken place from ‘disposal’ to ‘management’. However, as
Hayes says: ‘Waste is a construct that humanity invented at a time when industry lacked a deep
understanding of ecological processes. There is no waste in nature’ (cited in Imhoff 2005, p. 7).
Waste management practice is seen as a way to reduce or recycle waste, but in future the gen-
eration of waste may be synonymous with the generation of resources, as materials for use in
an integrated closed-loop cycle.
Waste management is generally concerned with what to do with waste arising, rather than
addressing the ‘problem’ at origin – the rising rate of materials acquisition and reducing dura-
bility of materials use. Hence, unsurprisingly, the volume of waste is rising. In Australia, the
rate of waste generated per capita is among the highest in the world (OECD 2002). In 2002–03,
more than 32 million tonnes of solid waste were generated by Australians, which is a rate of
4.35 kilograms per person per day (ABS 2007), most of which ends up in landfill. In Aus-
tralia, most households pay a set fee for their waste and recycling services as part of their local
council rates regardless of how much waste they generate. In contrast, most businesses pay for
waste disposal on a fee-for-service basis. This provides the commercial sector with an incen-
tive to minimise waste and maximise the amount of material recycled (Verghese and Lewis
2007), which may be a reason that recovery rates are lower for municipal waste than for
commercial waste.

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