WATCH: Scientists developing technologies to get rid of plastic waste

Image: Supplied

Image: Supplied

Published May 29, 2023


Despite a move by countries towards single use and degradable plastics, hundreds of tonnes end up on sites like these, every year.

United Nations scientists estimate that between 1950 and 2017, 9.2 billion tonnes of waste has been produced.

As much as 7 billion tonnes of it has been dumped in landfills or waste mountains.

One of the reasons plastics have become so popular is they are durable.

According to the National Institutes of Health in America most of the polymers and plastics in landfills remain unchanged, or they may degrade via some processes into fragments that either remain as produced or biodegrade to gaseous products such as carbon dioxide and methane.

Now scientists around the world are focusing on not just producing biodegradable alternatives to plastics, but producing technologies that can begin to get rid of the waste we are and have already generated.

According to the UN’s Environment Programme we could reduce our plastic waste by 80% by 2040 by using existing technologies and reusing and recycling.

Here at University College London (UCL) is the Engineering and Physical Sciences Research Council’s Plastic Waste Innovation Hub.

They are looking at a range of technologies which can dramatically cut the amount of plastic waste we humans produce.

These can be biological technologies such as using microorganisms like bacteria in this soil sample to eat away the plastic.

Helen Hailes the Professor of Chemical Biology here says designers and manufacturers need to think about how their products will end their lives, even before they start to produce them.

She says simply producing alternative polymers might not be a solution.

“So you have to be very careful about unintended consequences. So if there is a new polymer material that is going out into the market, then manufacturers have to think really carefully about the end of life of that material. Is it something that could go into some sort of compostable system be it industrial composting or anaerobic digestion? Or is it going to end up down at your local waste depot,” says Hailes.

Hailes believes part of the problem is that there is not a unified attempt to solve the problem.

Different countries have different systems of dealing with waste and manufacturers are using different technologies to try and take a market share with products which have green credentials.

In another lab at UCL a researcher is able to separate out each plastic product which travels under a special camera.

Her computer screen breaks down the composition of the products into pixels and tells her the knife and fork is made from potato starch.

The plastic lid is made from PLA a polymer which is also compostable.

This way refuse agencies can dramatically improve recycling and disposal.

It now needs to be scaled up.

“The ideal solution would be to be able to have systems to sort and degrade, whether that's a chemical degradation or a biological degradation. I don't think we can leave the amount of plastics that's currently in the oceans and people are looking at developing microbial based systems, for example, that might be able to help degrade plastics in a marine environment that could potentially have an impact as well,” says Hailes.

UN scientists say plastic pollution is leeching into many of our ecosystems including the oceans, damaging plant and animal health and habitats.

A lot of food waste in the UK and many other countries is sent to anaerobic digesters.

These tanks without oxygen use bacteria which breaks down the food waste in to a biomass.

They capture the CO2 and methane byproducts to make energy which is sold back to energy companies.

But a lot of food waste is put in compostable plastic bags.

Plastics dramatically cut the efficiency of these digesters so scientists here are trying to engineer microbes which break down the waste in digesters much faster.

“So we want to reduce those times. We want to reduce the time taken to degrade plastic in anaerobic digesters, to bring that into that three week window, which is what anaerobic digesters run commercially at now,” says biochemical engineer Dr Jack Jeffries.

The Kenya based UN Environment Programme (UNEP) is aiming to make any agreements made at the Paris summit legally binding.

It will be the second plastics convention UNEP has held.

But Irene Maithya, environmental advocate and lawyer at Kenya’s Moi University says that may be hard to achieve.

“Now we're talking about China, we're talking about India, Singapore or any other country. These are the countries that have huge populations. These other countries that have the huge pollution, when it comes to plastic. So if you're talking about any meaningful commitments and desire and seriousness on having a plastic pollution treaty, all countries, all member states must demonstrate that they are committed.”

Maithya believes the aim of an 80% reduction in waste by 2040 will need international will and political cooperation.

She says: “We would have to bring other stakeholders on board apart from the existing technology, new technologies, we would have to have a conversation with policy frameworks from government, the industry players and civil society organisations. So yes, it's possible for us to get that 80%, but technology alone would be limited.”

Hailes also believes the 80% reduction is a tough ask to meet.

“There are so many different recycling policies depending on where you live. There's got to be some conformity, and then the technologies will start to slot in place. But there's still a lot of basic research and developments to try and tackle how we might more effectively, you know, even simple things such as mixed composites, textiles, for example, that have mixed plastics in, how are we going to be able to be dealing with that? And those technologies are still needing to be developed because what we don't want to do is always repurpose and downgrade a material because ultimately it's going to end up in the environment.”

The Intergovernmental Negotiating Committee is set to meet for its second session from 29 May to 2 June at the UNESCO headquarters in Paris.

Its aim is to develop a legally binding agreement on plastic pollution for land and sea.

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