Environmental Engineering Reference
In-Depth Information
at a high cost in terms of depleted resources, fossil-fuel energy, and the
ecological footprint associated with its externalities. The unrealistic market
cost of the item often does not include its environmental cost discouraging
the user from re-using an item a number of times. The true cost of the
product taking into account all the costs is high enough to easily justify a
vigorous effort at reuse and recovery. There is no justification for any plastic
product made at a high environmental cost to be deemed a service life of
only a few minutes. The primary argument for considering plastic waste
as a resource is its high embodied energy and the thermal energy that can
be derived from it as a solid fuel. Heating values of plastics in comparison
to conventional fuels are shown in the bar diagram ( Fig. 9.3 ). In fact one
approach to recovering the energy is to use source-separated plastic waste
as fuel in power plants or in cement manufacture.
Figure 9.3 A comparison of the heating value of plastics and conventional
fuels.
In essence, sustainable growth demands that the linear unidirectional flow
of scarce nonrenewable materials from sources to waste be converted into a
cyclic flow to the extent practical. Recovery of waste has to be promoted and
implemented as an integral part of this change. The sustainability goal with
respect to plastic waste is twofold:
 
 
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