Tackling Plastic Waste for More Sustainable Science

Life sciences research produces plastic waste weighing a stunning 5.5 million tons, according to researchers from the University of Exeter – roughly the equivalent of 67 cruise ships.

The need to handle biological hazards and prevent contamination has led to a reliance on single-use plastics in the life sciences. While it may not be possible to completely remove plastic from the equation in the laboratory, approaches are being developed to reduce the amount of plastic waste generated as well as increase its reuse and recycling.

Sustainability is becoming an ever-growing issue, not just in the lab, with numerous governments imposing restrictions on single-use plastics and plastic waste.

At SLAS Europe 2024, Technology Networks had the pleasure of speaking with Tim Dillon, market manager (Nordics) at Mettler-Toledo Rainin, to learn more about sustainability in the context of a laboratory environment, and how more sustainable options can be implemented into scientists’ daily workflows.

Sarah Whelan (SW): The word “sustainability” is widely used in today’s world, but how would you define sustainability?

Tim Dillon (TD): There's a very simple definition of sustainability – to embrace doing something today in a way that it doesn't negatively impact your ability to do it tomorrow. In other words, don't make a mess today that you can’t clean up tomorrow. That's the common-sense approach, to stop doing things that are a net negative in the long term that can’t be recovered from and that are going to stockpile problems in the future.

SW: What would you say are some of the main problems when it comes to sustainability in a laboratory environment?

TD: There are often difficulties with the materials that are being used in a lab. Biosafety and health and safety considerations mean the materials used can't always go into the usual sustainable waste streams. For example, some labs must incinerate or autoclave waste before it leaves the lab.

There are also more general problems, which I put into the “naivety” category. This is where people have false assumptions about what's happening with their waste, or they aren’t aware of the wider costs of the materials they're using. They don't understand that there are better options, or they haven’t thought about it, so they haven't had the opportunity to think about the impact of what they’re doing, how to mitigate it and what choices they have.

In science, if something works and it gives you results, you’re often very reluctant to change things around in case things don’t work. But you need to have an open mind and a willingness to consider the risks of changing what you’re doing. Often, it's an irrational fear, inertia or sometimes a lack of motivation.

SW: At SLAS Europe 2024 you displayed some examples of more sustainable options for pipette tips. Can you run through the various generations of products?

TD: Generations is a good way to put it because we started way back in the early 90s, before sustainability was as recognized as it is today. We produce single-use plastic products, so it's at the front of our minds that we have a responsibility to make sure that resource is used wisely and that we apply the principles of good design and innovation.

Our first innovation was to develop the tower rack system, which allows you to refill your polypropylene rack. Rainin developed them in the first instance, and the rest of the market followed. This took about 80% of the plastic out of the equation, allowing energetically expensive polypropylene racks to be reused. Our next innovation was to develop a single rack refill for that energetically expensive polypropylene rack, which allowed it to be refilled with filter tips. Filter tips can’t be used in a tower system because the top row nests inside the bottom row, and the filter gets in the way. So, we have an individual polyethylene terephthalate (PET) plastic clamshell refill that takes a lot of the plastic out of the equation for filter tip racks.

We also developed a hinged rack that is made entirely of PET. This takes half the plastic out of the equation and is half the weight, substituting energetically expensive grade five polypropylene for much easier to recycle and energetically less expensive grade one PET.

Our next generation – the EarthRack™ – moves away from plastic as much as possible. We've taken all the plastic out of the rack lid and rack base and replaced it with a purified cellulose material. This is compostable, in either an industrial composting setting, or what's termed a “home composting” setting. Home composting doesn't mean that you take it home, but that it doesn’t need special conditions and will rot when it comes into contact with the soil, leaving the soil in an improved state after it decomposes. That's the latest evolution. After all, the most sustainable plastic is the plastic you don't use.

Rainin’s pipette tip products, including the EarthRack (right). Credit: Technology Networks.

SW: How are these increasingly sustainable products being integrated into day-to-day workflows for scientists?

TD: With minimal effort. It's a matter of being aware that you have choices, and making the choices that offer you the most sustainable product. When it comes to the pipette tips that go inside of all these racks, Rainin believes that there's no compromise to be made there. All our tips are the same high-quality material, which we call BioClean Ultra – or BioClean Green, in the case of EarthRack. That is non-negotiable, so the tips don't change – the only thing that changes are the racks the tips come in, so you don't have to change anything that you do in the lab.

SW: What is the status of the development of the EarthRack?

TD: EarthRack is an ongoing story. We’re quite advanced in prototyping – all I can say is watch this space. Everything is in development with Rainin and we have a culture of innovation and change; we don't stand still. We always seek to address what the market and the consumer want. If the consumer demands more sustainable products and puts their practice where their demand is, then the market will develop those products. We realize this is going to be a continuous process, and there will be further iterations taking more plastic out of the equation.

A demonstration of EarthRack’s compostable properties. Credit: Technology Networks.

SW: What do you think needs to be done to aid sustainability while avoiding “greenwashing”?

TD: In a nutshell, it’s education. People need to know what the pitfalls and common failings are. Greenwashing often has a negative connotation and people feel they’re being misled; often it's innocence or a naïve misunderstanding of the relevant points.

Take recycling polypropylene, for example. Most pipette tip racks are made from polypropylene, which is a grade five resin. The international resin scale goes from one to seven, with one being almost universally recyclable and seven being virtually non-recyclable. Polypropylene is at the wrong end of the scale – it requires specialist recycling, so if it goes in your general plastic waste stream it's more than likely going to be diverted to either landfill or thermal energy recovery, so that’s one innocent mistake.

Even with dedicated polypropylene recycling, you assume that the polypropylene is going to make a new rack – and that is also a false assumption. It generally can't be used to make the same material again and recycled polypropylene isn’t particularly valuable or sought after material on the aftermarket. This is because the average chain length mix of the polymer changes during recycling (the molar mass distribution changes). This changes its mechanical properties like tensile strength, brittleness, flexibility and its ability to flow through an injection mold. Though you may send your polypropylene to a dedicated polypropylene recycler, it's not going to make a new rack, so it’s not stopping the flow of oil into the product life cycle – something you thought you were doing when recycling.

For the plastic we do need to use in the racks, we can use PET. This is a grade one resin that is almost universally recyclable and goes in any mixed recycling stream, so you can be confident that it will be recycled. It also has a higher value on the aftermarket because PET recycling is an even and regular process in which the polymer is cleaved one molecule at a time, resulting in a recyclate with the same properties as virgin PET, so you can make the same product and recycle it up to 10 times. This stops the flow of new oil into the product cycle and cuts it off at the product manufacturing stage. In this way, naivety or lack of education about recycling plastics can often lead people to do the wrong thing or not act effectively. There's nothing deliberate, we just need education.

Tim Dillon was speaking to Dr. Sarah Whelan, Science Writer for Technology Networks.

About the interviewee:

Tim Dillon is the market manager (Nordics) at Mettler-Toledo Rainin. He holds a BSc in biology and a postgraduate diploma in analytical techniques from the University of Bedford.