Evaluation of Plastic Waste Management in Thailand Using Material ...

Similarly, some recycling factories want to clean plastic waste by themselves, hence they
build the pretreatment process in the factory. Figure 4.17 presents the sorting of plastic
wastes at the pelletizing factories, and Figure 4.18 shows the washing process of plastic
scraps.
Figure 4.17 Sorting unit in pelletizing
factory
60
Figure 4.18 Washing unit in pelletizing
factory
After cleaning plastic wastes, plastic scraps are melted through the thermal process. The
product from pelletizing factory is plastic resins (masterbatch). Finally, recycled resins are
used to produce plastics in the plastic industry again. For example, Asia Piboonwong Ltd.,
Co. has the plastic bags factories, so the owner uses recycled resins to produce plastic bags.
Figure 4.19 shows pelletizing process, and the recycled pellets are illustrated in Figure
4.20.
Figure 4.19 Pelletizing process
Figure 4.20 Recycled resins
Materials which are used to produce plastic goods are considered about contamination,
raw material prices that a used plastic cost will increase if raw material is the high cost, and
types of plastics (i.e., PP and PET costs are higher than PVC). The prices of used PP and
used PET are about 15-17 Baht per kilogram while the used PVC cost is around 8-11 Baht
per kilogram. Used plastics that are mostly contaminated have lower costs than high purity
plastic.
The quality of recycled resins affects the prices of recycled resins. Color of recycled resins
is the one factors used to set the middle prices. Table 4.5 shows the prices or recycled
resins classifying by color. Black color resins are cheapest compared to others because this
color is from the mixing of every plastic color. These black resins can be used to produce
only black plastic products like garbage bags, buckets, and pots.