In the name of climate #4: can plastic really be recycled?

One of the many impacts of the Covid-19 pandemic has been the significant increase in the use of plastic across the world, in both the public and private sector: according to the Chinese Ministry of Ecology and the Environment, at the virus’ peak 240 tonnes of medical waste were produced each day in the city of Wuhan alone, compared to 40 tonnes produced before the emergency.

In fact, the pandemic has refocused attention on the environment, and with this the topic of recycling and the effective possibility of disposing of it. In Europe, approximately 20% of all plastic produced is recycled; globally, this figure stands at somewhere between 14 and 18%. In Italy, only 30% of collected plastic is recycled, using a mechanical recovery process, while 40% ends up in landfill or is burned in waste-to-energy systems or incinerators.

Mechanical recycling involves collecting and separating plastic waste, which is then cleaned and shredded into flakes before being reused. However, each step of the process is onerous and often doesn't lead to the desired results. Moreover, not all plastic is created equal: in fact, plastic is composed of different components that determine how effective the recycling process is likely to be.

Even if we separate our waste, the plastic we throw in the trash is often “impure”, meaning it has come into contact with food products or other elements that can compromise the recycling process, even after the cleaning and separation processes. The problem is exacerbated by thermomechanical degradation which occurs when the polymers are superheated, making the plastic less reusable over time: unlike glass, this means plastic cannot be infinitely recycled.

The environmental impact caused by the difficulty of mechanically recycling plastic above all has an economic cost: according to a 2019 study published in the Marine Pollution Bulletin, plastic pollution in the oceans has already cost 2500 billion dollars in lost use of marine economic resources.

The problems associated with the mechanical recycling of plastic could be overcome using chemical or molecular processes: heat can be applied to break the chemical bonds in the plastic to generate a liquid that can be used to produce a new virgin material, thus recovering all of the recycled plastic; however, this process has never been applied on a large scale and is extremely costly, while certain researchers believe it can release toxic substances into the environment.