Table 2 shows the odor concentration results in the downwind
boundaries of various plastic waste recycling plants. The waste collection
and sorting plants generated common waste malodor and
the odor concentrations at the boundaries were 78–100 OC. However,
the recyclable solid waste in sorting plants varied, and the
malodor emission was not entirely attributable to plastic waste.
The odor emitted from shredding plants was sour, which may have
been caused by fermentation of the residual organic matter inside
the bottles or containers. The odor concentrations at the boundaries
of shredding plants were 30–100 OC. Thoroughly cleaning these
containers immediately after transport to recycling plants may resolve
this odor problem. Pungent and burned plastic malodor were
frequently noted at the boundaries of melting and powdering
plants, where odor concentrations were measured at 100–229 OC.
According to Taiwan EPA regulations and standards, the maximum
allowable odor concentration at the boundaries of any plant in
industrial and agricultural regions should not exceed 50 OC (less
than 20 OC in industrial areas in Korea). In this study, most of the
odor concentration at the boundaries of plastic recycling plants exceeded
Taiwan EPA standards, particularly melting and powdering
plants, which indicated the need for improved odor control.