Plastics seem to be constantly making headlines at the moment, and not usually for good reasons – it’s likely that a quick Google search will turn up results on plastic pollution of beaches and oceans, and innovative ways to replace them. In 2017 the UK recycled just over 45% of household plastic waste, but this still leaves over half to go. It’s clear that there is a problem, but a great deal plastic that we use in our daily lives can be recycled, so why is so much plastic thrown away and who needs to act to change it?
Part of the problem is how good plastic is as an engineering material – plastics have many benefits to consumers and producers, which have resulted in their use in almost every area of daily life. These benefits include their low cost, good material properties and ease of forming, which offers almost unlimited shapes and sizes for plastic products. A negative result of this high plastic use is the high rate at which they are thrown away and wasted, as the low cost especially means plastics are great for single use, throwaway items. Waste plastics and their disposal is a major environmental issue, with over 50 million tons of plastic waste produced annually by the USA and Europe alone.
Single use plastics present a large part of the plastic waste problem, and several strategies have been used to tackle their massive use. These include policy changes (think of the UK’s 5p carrier bag charge) or pressuring companies to provide alternative materials (often seen in the various alternative straws used instead of plastic). A shift towards reusable, long-life products is definitely a good way to reduce plastic waste and this is the direction taken by many producers and consumers. However, many single use plastics can be recycled, so why can’t we have our single use plastics and simply recycle them when we’re done?
One issue with our recycling sytem is sorting – current recycling of plastics is reliant on effective sorting to give a quality product, as mixing different plastics can negatively affect their new material. For example, even a small amount of PVC in a stream of melted PET during the recycling process will release hydrochloric acid gas, due to the higher temperature needed to melt PET. This significantly harms the recycled material as the acid degrades some of the new PET resin.
The problem with this is that many recycling centres sort by hand, so waste may be sorted incorrectly due to similar plastics being hard to tell apart by eye, by human error or by a lack of staff at recycling centres leading to an insufficient ability to handle large amounts of waste. This leads to some perfectly recyclable material being lost to landfill, with some studies estimating that as much as 20% of recyclable plastic that makes it to an appropriate recycling plant still goes to landfill.
Sorting can be improved with a number of new technologies including flotation, where waste is floated in a solution of very specific density so that certain plastic compounds will float to the top and the rest will sink. However these technologies are new and expensive, and governing bodies in charge of recycling may not currently have enough incentive to spend large amounts of money on them.
Some plastic isn’t even recyclable at regular recycling plants, just because of how it is manufactured. A report from councils in England and Wales pointed to coloured and mixed plastics as a major problem, including the fact that black plastic (often used in food packaging to make the food look better) can’t be scanned by many sorting machines. Some food packaging also contains multiple types of plastic, and if one can’t be recycled the whole product has to go to landfill. This report argued that there needs to be more motivation for producers of plastic items to make their products recyclable, and suggested financial incentives as a way to achieve this.
One key issue that reduces the recycling rate of waste plastic is household participation. One study found that while nine out of ten UK households claim to recycle, the total percentage of recyclable household waste being correctly sorted is around 10% (33). This problem may be partly due to confusing plastic codes, and different areas being able to handle different types of plastic – anyone who has moved house and struggled to learn their new bin system will understand the struggle of remembering what goes in which bin, and even people who follow the system carefully can make mistakes. Better public understanding of recycling could significantly boost the recycling rate, but achieving this is a challenge and it’s not clear who should be responsible. Should governments and local bodies have to provide better information, or do producers of plastics need to educate people on what to do at the end of life?
Another, fairly new development, is often referred to as “closing the loop”. This involves companies that produce and sell plastics creating new ways to handle their own waste and recycle it in-house. There are also a range of startups that deal with handling waste on behalf of producers, helping create a circular economy and remove waste plastic from the environment. One good campaign that recently caught my eye was Burger King’s meltdown programme, which allowed customers to return the small plastic toys available with children’s meals so that the company could recycle them properly. However these schemes are not common and even when they are, the incentives are not always there for consumers to them.
It’s clear that there are a wide range of factors that contribute to our low recycling rate, and being able to overcome these is key to overcoming plastic waste. Who do you think needs to make the biggest changes? Is it plastic producing companies who need to think of new, biodegradable materials, consumers who need to recycle more carefully or governing bodies who should invest in the proper recycling infrastructure?