At the recent inaugural virtual Global Research Innovation in Plastics Sustainability conference, Physical Chemistry Professor Tony Ryan, OBE, from the University of Sheffield, offered an alternative take on the practice of landfilling.
At present, plastic sustainability research and innovation is focused on reducing the thousands of tonnes of plastics ending up in landfill each year, as well as a few other key areas. Plastics in landfill is counter to the sector’s Reduce, Reuse and Recycle mantra, and polymers can take thousands of years to decompose. But as intuitive as this goal is, it may not always be at the heart of plastics sustainability, he said.
“Am I suggesting that we will master the circular model of plastics, or develop some new degradable polymer that can replace the long-lasting counterpart wholesale, thus rendering this goal obsolete? Maybe, but even so, the future will see us burying plastics on purpose, as an act of sustainability rather than a crime against it.
Outside of plastics sustainability, another key area of scientific research and innovation is carbon sequestration. If we are to survive on this planet, we need to come up with ways of removing carbon from the atmosphere permanently.
Despite our ever-increasing technical know-how as a species, Mother Nature has us beat in this regard. Photosynthesis remains the most efficient Negative Emissions Technology available to us, and by a considerable margin. Where Mother Nature lets us down, however, is at the end of the cycle when plants die and decompose, and the carbon dioxide they temporarily stored, and even more potent greenhouse gases like methane, are released back into the atmosphere.
That’s where polymer science can come in. At present, with crops for humans and livestock, we use maybe 20% of a plant, possibly even less, the rest winds up as agricultural waste. To prevent this agricultural waste from continuing to contribute to climate change, we can simply ferment it into ethanol, dehydrate the ethanol into ethylene, and convert the ethylene to polyethylene.
Now we can produce as much plastic as we like, use it, and bury it, flipping the long-lasting nature of polymer waste on its head as a benefit, to permanently sequester carbon from the atmosphere.
The only reason we aren’t doing this already is the process comes with a carbon cost, but it doesn’t have to. All that needs to happen for this model to actually work, and contribute to the fight against climate change, is renewable energy to power the process, and we’re not far away. So, plastics in landfill will stop being an obstacle in the way of sustainability and will instead be considered a great tool for it.”
The next GRIPS conference is scheduled for 15 – 17 March 2022.