Environmental Engineering Reference
In-Depth Information
pollution and global warming) are at least partly correct, then to be sustainable we
must reduce B . There are two ways to do this:
1. dematerialisation: use less resources per person and hence produce less waste; and
2. transmaterialisation: use different materials and have a different attitude to 'waste'.
While many argue for dematerialisation, this is a dangerous route to go down as it
typically requires that the developing nations listen to the developed nations and
'learn from their mistakes'. While many of our manufacturing processes in regions
such as Europe and North America are becoming increasingly more efficient, we
continue to treat most of our waste with contempt, focusing on disposal and an
'out of sight, out of mind' attitude. We also have to face the unavoidable truth that
people in developing countries want to enjoy the same standard of living we have
benefited from in the developed world; pontificating academics and politicians in
the West talking about the need to reduce consumption will have little impact on
the habits of the rest of the world!
Transmaterialisation, as it would apply to a sustainable society based on con-
sumer goods, is more fundamental. It makes no assumption about limits of con-
sumption other than the need to fit in with natural cycles such as using biomass at
no more than the rate nature can produce it. Transmaterialisation also avoids
clearly environmentally incompatible practices (such as using short-lifetime arti-
cles that linger unproductively in the environment for long periods of time, e.g.
non-biodegradable polyolefin plastic bags) and bases our consumption pattern on
the circular economy model, with spent articles becoming a resource for other
manufacturing [1]. This model is essentially the same as the green chemistry con-
cept, at least in terms of the chemical processes and products that dominate con-
sumer goods, described in more detail in Section 1.4.
1.2 Renewable Resources: Nature and Availability
We need to find new ways of generating the chemicals, energy and materials as
well as food that a growing world population (increasing P ) and growing individ-
ual expectations (increasing C ) needs, while limiting environmental damage. At
the beginning of transmaterialisation is the feedstock or primary resource and this
needs to be made renewable (see Figure 1.1). An ideal renewable resource is one
that can be replenished over a relatively short timescale or is essentially limitless in
supply. Resources such as coal, natural gas and crude oil come from carbon diox-
ide, 'fixed' by nature through photosynthesis many millions of years ago. They are
of limited supply, cannot be replaced and are therefore non-renewable. In contrast,
resources such as solar radiation, wind, tides and biomass can be considered as
renewable resources, which are (if appropriately managed) in no danger of being
over-exploited. However, it is important to note that while the first three resources
can be used as a renewable source of energy, biomass can be used to produce not
only energy but also chemicals and materials, the focus of this topic.
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