Polyethylene terephthalate (PET) is a common packaging polymer around the world. In South Africa, it is widely used to manufacture beverage bottles, vegetable punnets, yoghurt cups and even clothing. PET is easy to recycle and has many beneficial uses – making it the second-most popular packaging material in the country.
Most of the plastics used for various packaging applications are mechanically recycled in South Africa. These materials are often picked, sorted and washed by hand before being processed. However, PET is different. Owing to the volume of PET recyclable waste in South Africa, many recycling facilities use technology to sort and process this polymer.
PET is recycled using automated technology
Discarded PET packaging is collected by waste management companies and informal waste pickers working at landfills. They source and collect the PET plastic before bailing them into dense packs for transport. These bundles of plastic waste are then taken to recycling facilities where the process begins. The bails are fed onto a production line that first passes under strong magnets to remove any metal contaminants.
Next, the PET plastic is fed to a hot washer that removes sand, dirt and oils. The labels on beverage bottles are also removed in this washer. These labels are collected and sent to another recycling production line. The cleaned PET packaging is then fed along a conveyor and scanned using high-speed optical sensors and infrared cameras to sort the waste.
These sensors detect the type and colour of the PET waste, sorting it into batches of clear, green, brown and mixed colours. It is necessary to sort the plastic by colour as this results in a recyclate with consistent colours at the end of the process. If brown bottles were mixed with green ones, the batch would come out a dirty olive colour.
Once sorted by colour, these bails of recyclate are sent to a granulator to be turned into small flakes. These flakes are then washed in three stages to remove any residual contaminants and sticky label fragments. The flakes are sent to a heater, which dries them, before being fed to a high-temperature oven to melt. This melted PET resin is extruded (stretched into long strands), cooled and chopped into small pellets.
These pellets of plastic are sold to manufacturers, who can then use the recycled PET (rPET) to create new beverage bottles. These rPET fibres are also used to manufacture a variety of products, such as polyester clothing, carpeting, underbody shields for vehicles and recycled PET packaging products.
Other methods of recycling PET packaging
The Coca-Cola Company is trying to find more sustainable ways of recycling its PET bottles. It has started to chemically recycle its plastic bottles. This process breaks the polymer down into its basic molecules, separating the colourants, contaminants and impurities at the same time. The result is a number of near-pure products that can be processed back into PET packaging or used for other applications.
While this chemical recycling process is only being trialled in Europe, it could make its way to South Africa in the near future. Right now, South Africa has some of the highest recycling rates in the world – beating Europe by over 15%. PET is one of the easiest plastics to recycle and it can be processed again and again. This has numerous economic and environmental benefits if the plastic waste is disposed of responsibly.
Plastics SA represents all sectors of the South African plastics industry. Together with our associations, we play an active role in the growth and development of the industry and strive to address plastics related issues, influence role-players and make plastics the material of choice.
Plastics SA has been mandated to ensure a vibrant and sustainable plastics industry in South Africa. The plastics sector is uniquely placed to meet the needs of a sustainable society and to deliver solutions to many challenges such as recycling, climate change, water scarcity, resource usage and energy recovery.