PET "bottle-to-bottle" cycle is steadily gaining ground

Light, break proof drink bottles made of polyethylene terephthalate, in short PET, are extremely popular with retailers and consumers. Up to two thirds of the plastic bottles that are disposed of in yellow bags or bins after use are made of this high-quality plastic today. The Deutsche Gesellschaft für Kunststoff-Recycling mbH reacted to this development at an early date. Together with partners, it established its own concept for PET recycling and has consequently improved the eco-efficiency with which bottles can be mechanically recycled.

Processing of PET

The first step in recycling is processing:  Four processing plants for re-sorting plastic bottles marked with the Green Dot have been in operation since the end of 2001. With the aid of modern optoelectronic systems, the bottles are separated according to plastic type and colour. Near-infrared modules first sort the material into the target fractions polyethylene (PE), polypropylene (PP) and PET.

Then colour-detection systems separate the PET fraction into clear PET, coloured PET and, as an option, PET light-blue and light-green. At the end of the processing line, fractions with a purity of 98 percent are available for recycling. At present, PET is processed by four DKR partners:

• TPP Recycling GmbH, Ibbenbüren
• RWE Umwelt Aichach GmbH, Lauingen
• Schwarzataler Kunststoff GmbH, Eisfeld
• Recycling-Zentren Brandenburg GmbH (RZB), Eisenhüttenstadt

Processing in the fibre industry

Around 80 to 90 percent of the used PET bottles are currently forwarded to the fibre industry where they are processed into fibres and fleece materials which, for instance, are used to produce roof insulating materials, insoles for shoes, inside roofing for cars or filters. However, fibre production will decrease in future and the share of bottle-to-bottle recycling will continue to rise. For example, Cleanaway Plastic Recycling GmbH & Co KG in Rostock started to recycle PET with the URRC process at the beginning of 2002.

Bottle-to-bottle cycle

The URRC technology is being used in Rostock for the first time in Germany. It was developed by the United Resource Recovery Corporation and Coca-Cola. In the course of this process, clear PET drink bottles are processed into extremely pure flakes that are suitable for the production of new drink bottles. The bottles are first shredded, washed and any labels and caps are removed. This pre-treatment step is followed by further mechanical and chemical cleaning processes. At the end of these, the ground stock is once again suitable for contact with foodstuffs. Other companies are also opting for bottle-to-bottle recycling. For instance, Smalbach-Lubeca AG has established an economic bottle-to-bottle recycling route with the optimised Supercycle process.

Option chemical PET recycling

Only PET packaging that has been sorted homogeneously or processed is suitable for high-grade mechanical recycling. As a possible alternative for coloured and mixed detergent bottles, dishes or films, the DKR is currently investigating the use of chemical recycling processes.