Environmental Engineering Reference
In-Depth Information
which types of plastics are prevalent in the MSW stream.
Table 9.1
shows
that four resins (low density polyethylene (LDPE), polypropylene (PP),
HDPE, and PET) dominate the plastics fraction in the MSW. Of these,
the PET and HDPE are recycled to a significant extent (at 28% and 6%
respectively). Majority of the plastic wastes however is landfilled. The
United States lags behind European countries such as Sweden, Austria,
Belgium, and Germany as well as Japan in plastics waste recovery.
Amount × 10
6
tons
Categories
Recovery
(%)
Durable goods 10.9
PP, LDPE, HDPE
6.4
Nondurables
6.4
LDPE, PP, PS
Negligible
PET ~ 29
Bottles
containers
5.3
PET, HDPE
HDPE ~ 27
Bags, sacks,
wraps
3.9
LDPE, PP, HDPE
11.5
Other packaging 4.45
LDPE, PP, PET
Total
31.0
LDPE, PP, HDPE,
PET
8.2
LDPE estimate includes LLDPE.
a
Indicated in the order of decreasing fraction in the category.
9.1 RECOVERY OF WASTE
Post-consumer plastics are classified as waste not because they have no
further intrinsic value, but often because these have lost a single critical
aspect of their functionality during use. Food service plastic items illustrate
this particularly well. A used cup or bottle is no longer clean or sterile
but the physical and mechanical properties, the thermoplastic nature, the
bio-inertness and the barrier effectiveness of the “waste” is no different
from those of unused item. Clearly, it is still a valuable resource synthesized
