Environmental Engineering Reference
In-Depth Information
Theoretically, all thermoplastics can be recycled. However, it is the
availability of recycling infrastructure, rather than physicochemical
feasibility, that determines the extent to which a given product will be
recycledinpractice.Thecostofrecycling,fromcollectingthepost-consumer
products at curbside to transporting the recycled plastic pellets to
fabricators, invariably determines the market price of the recycled resin.
Where this cost is well below that of virgin plastic, as with HDPE grades
used in milk jug fabrication or PET grades used in blow-molded soda
bottles, recycling makes good business sense. In the United States, these
two postconsumer plastics products therefore enjoy significant levels of
recycling.
Figure 9.12
illustrates the general process.
Figure 9.12
A general scheme for recycling of plastics recovered from
MSW, illustrating closed- and open-loop pathways.
In 1988, the Society of Plastics Industry developed the now-widely used
set of seven identification codes for six classes of plastics (the seventh is a
are intended to help consumer determine recyclability and encourage
separation of plastics at source. But these can in fact confuse the consumer
