A SORTING SYSTEM FOR IMPROVING THE QUALITY OF RECYCLED PET PLASTIC RESINS

It is well known that post-consumer plastics have become a tremendous burden uponour waste disposal system. Although plastics constitute only about 9% by weightof municipal solid waste, they occupy approximately 1/4 the volume of the wastestream. A particular increasing problem for the recycling of PET is the growthin the use of very lightly tinted PET bottles, particularly light blue tintedbottles for bottling of drinking water and household liquids. Existing automatedprocesses for sorting bottles by color are unable to recognize the light bluetint and generally direct these bottles into the clear PET product, whichconstitutes about 80% of recycled PET and is the highest valued of the PETrecycled products, resulting in a contamination of the product resin. Thetechnical objective of the Phase I proposed research is to establish feasibilityfor development of an automated high speed sorting system for sorting lightlytinted plastic bottles from clear plastic bottles.