Page 66 - Materials Chemistry, Second Edition

Life cycle assessment and waste management

Table 6.1 Recycling percentages of packaging materials in Australia and the USA (Imhoff 2005; 53
NPCC 2005)
Packaging materials Australia (2003) USA (2000)
Paper and cardboard 64% 56%
Glass 35% 26%
Steel 44% 58%
Aluminium 64% 55%
Plastics 20% 9%

When packaging waste fractions are sorted, they are sent to numerous reprocessing desti-
nations. High-value materials such as polyethylene terephthalate (PET) and glass are generally
reprocessed locally into recyclate for new packaging. In contrast, due to limited local facilities,
materials such as polypropylene (PP) and mixed plastics are generally sorted together and sent
to other countries for reprocessing into lower grade applications like plant pots.
When materials such as plastics and glass are sent to landfill, although they do not break
down and cause leachate and emission problems, they are a lost resource which could be used
to displace virgin material production in the economy. Food and garden waste, when com-
posted and applied to soil, can increase crop yields and reduce the application of fertilisers.
When organic material breaks down in the anaerobic environment of landfill, it can generate
greenhouse gas emissions. LCA studies conducted in other countries to investigate the man-
agement of post-consumer waste – recyclables, organic fractions and residual wastes (e.g. Weitz
et al. 1999; Beccali et al. 2001; Smith et al. 2001; US EPA 2002) – have demonstrated the benefits
of diverting waste from landfill.
For many years governments and industry have encouraged households to recycle. By the
late 1990s it was evident that there was strong public support for the separation of used packag-
ing materials for recycling. Although this support was based on the assertion that recycling
was ‘good for the environment’, as it saved resources and would result in less waste to landfill,
scientific data was necessary to inform the debate. An Australian LCA study demonstrated
that there were substantial benefits from recycling common packaging and paper materials
(see Section 6.2.1). This work was further supported by the Independent Assessment of
Kerbside Recycling Study, undertaken by Nolan-ITU and SKM Economics (2001) (see Section
6.2.2). However, neither study assessed management options for organic material, which is a
major component of the domestic waste stream.
Over recent years there have been substantial development and diversification in technolo-
gies to deal with residual (generally not recycled) and organic waste fractions. These technolo-
gies usually provide one or more of the following outcomes:
s energy
s useful organic material
s volume reduction
s stabilisation of the organic fraction and/or toxins.
LCA can be used to indicate how any given waste management technology may affect
other aspects of the waste stream and the waste management system itself, with positive or
negative environmental impacts. Any evaluation of the technology needs to take the wider
impacts into account. Those possible impacts were examined in a study that aimed to evaluate
the environmental impacts of a range of waste management scenarios using different waste
treatment (resource recovery) technologies in a full life cycle context (Grant et al. 2003) (see
Section 6.2.3).

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