Science’s battle to tackle plastic waste
Plastic waste is one of the major environmental challenges that activists have faced in recent years. I spoke to two specialists from Imperial College London about their research into tackling these issues.
Plastic waste can take centuries to biodegrade. It can be washed into oceans, and be ingested by maritime species who mistake it for prey. They can also suffocate on plastic packaging.
The world’s waterways are not the only place where the impact of plastic is dangerous. Plastic can also release harmful chemicals into the environment.
Companies have, in response to these concerns, begun to attempt to move away from plastic to paper. However, Dr Jason Hallett, a chemical engineering professor at Imperial College London, the principal investigator in a project to reduce plastic pollution, points out: “I do worry sometimes, worry something like this can run away quite fast, they banned the plastic straws and said ‘ok we’re going to put paper straws’. Paper is much worse for the environment than plastic, so we have solved the plastic straw waste problem, by creating a much bigger problem. That’s very silly, right? Why would you do that?”
McDonald’s is one of the companies that stopped using plastic straws, but the new paper alternatives are actually unable to be recycled, as the straws are too thick to be processed. Customers also complained the straws dissolved too quickly, making it difficult to actually drink using them.
Dr Hallett points out that plastic is common because of its usefulness: “It solves a lot of problems that we have no other better solutions for.”
Picking up his phone from the desk, he argues it is possible to manufacture it using metal rather than plastic but “it would weigh between five and ten times more, so that means when it would be made, distributed, me carrying it around, it would have higher CO2 emissions during the manufacturing and distribution process.”
CO2, or carbon dioxide, is a greenhouse gas, meaning if a large quantity of emissions is produced it can contribute heavily to global warming. The gases form a blanket over the atmosphere, trapping in warm air.
Dr Hallett continues: “For a lot of products, plastic is a necessary component of the way we set up our culture.”
He argues that replacing plastic with glass would increase CO2 emissions “four-fold”, and the issue with waste also needs to be tackled with a look at human behaviour.
He explains: “The biggest problem at the moment is that once we throw something away, it has no value. That’s sort of the wrong way around of thinking about it. If plastic had a value attached to it, that was how easy or difficult it was to recycle, then we start to move in a direction where we have more of an appreciation of what the impact of the material is on the environment. A piece of waste plastic does cost energy and therefore money for the Earth to get rid of, to deal with.”
Dr James Hogg, a research associate on the project explains: “The main aim of the research is to make it more easy to do the right thing. If you make that easy, then people will do it.”
He argues from the point of view of businesses, the ability to promote themselves as green is in their interests, as it can give them an edge in the market. He argues, tackling plastic waste is complicated because it involves looking at more than one type of material.
Dr Hogg explains: “Your clothes are made of nylon, a plastic bottle is made of PET, a plastic bag’s made of polyolefin, there’s lots of different kinds of materials. You can’t necessarily treat them all in the same way. When you get to multi-layered packaging, how do you separate the layers? You can’t just crunch it up and mechanically recycle it. All the layers become intermixed.”
He says that the problem with paper cups is they often have a small amount of plastic in them to prevent the liquid dripping through the cup. Whilst acknowledging the amount of plastic was much smaller than a full plastic cup, there was still a challenge in separating the layers.
He added that at Imperial, work was being done to find a method of separating the paper and plastic to allow for recycling and that there was “reasonable success” with “preliminary experiments.”
An alternative to plastic bottles, which was trialled at last year’s London Marathon, was to use edible seaweed pouches which can be thrown away and biodegrade in a matter of weeks. Although they were only used in the final 3.2 miles.
He pointed out that before using such biological resources, the impact on natural ecosystems has to be analysed: “I couldn’t talk on the specifics of seaweed itself and how much seaweed you harvest from a plot of ocean floor, but that’s something you would need to consider.”
He used biodiesel as an example. Biodiesel is another biological resource, a diesel fuel created from vegetable oil or animal fats.
Dr Hogg noted: “One of the issues with biodiesel is because it’s worth lots of money, countries like Indonesia chop down loads of rainforest to produce palm oil, so they can turn it into biodiesel.”
Mainstream science recognises the importance of protecting the environment, and plastic waste is one of the issues that needs to be tackled. The challenge currently is working out the most efficient way to deal with the issues that this waste brings. Cost, complexity and sustainability are the main challenges in working out what the solutions are. As Dr Hallett explains, the industry wants a solution as well: “They’re not happy about it, this is not a thing that they want. But there’s no alternative.” Science is challenged with determining what the alternative is.
This is an adapted version of an article written for the print edition of Yoots. A journalism project for City, University of London’s Advanced Practical Journalism: Online/print module.