Plastic recycling

Plastic recycling

Clockwise from top left:

• Sorting plastic waste at a single-stream recycling centre
• Baled colour-sorted used bottles
• Recovered HDPE ready for recycling
• A watering can made from recycled bottles

Plastic recycling is the processing of plastic waste into other products.^[1][2][3] Recycling can reduce dependence on landfill, conserve resources and protect the environment from plastic pollution and greenhouse gas emissions.^[4][5] Recycling rates lag behind those of other recoverable materials, such as aluminium, glass and paper. From the start of plastic production through to 2015, the world produced around 6.3 billion tonnes of plastic waste, only 9% of which has been recycled and only ~1% has been recycled more than once.^[6] Of the remaining waste, 12% was incinerated and 79% either sent to landfill or lost into the environment as pollution.^[6]

Almost all plastic is non-biodegradable and without recycling, spreads across the environment^[7][8] where it causes plastic pollution. For example, as of 2015, approximately 8 million tonnes of waste plastic enters the oceans annually, damaging oceanic ecosystem and forming ocean garbage patches.^[9]

Almost all recycling is mechanical and involves the melting and reforming of plastic into other items. This can cause polymer degradation at the molecular level, and requires that waste be sorted by colour and polymer type before processing, which is often complicated and expensive. Errors can lead to material with inconsistent properties, rendering it unappealing to industry.^[10] Though filtration in mechanical recycling reduces microplastic release, even the most efficient filtration systems cannot prevent the release of microplastics into wastewater.^[11][12]

In feedstock recycling, waste plastic is converted into its starting chemicals, which can then become fresh plastic. This involves higher energy and capital costs. Alternatively, plastic can be burned in place of fossil fuels in energy recovery facilities, or biochemically converted into other useful chemicals for industry.^[13] In some countries, burning is the dominant form of plastic waste disposal, particularly where landfill diversion policies are in place.

Plastic recycling is low in the waste hierarchy, meaning that reduction and reuse are more favourable and long-term solutions for sustainability.

It has been advocated since the early 1970s,^[14] but due to economic and technical challenges, did not impact the management of plastic waste to any significant extent until the late 1980s. The plastics industry has been criticised for lobbying for expansion of recycling programmes, even while research showed that most plastic could not be economically recycled.^{[15][16][17][18]} This has resulted in occasions where plastic waste dropped into recycling bins has not been recycled, and been treated as general waste.^[19]