A new game plan for plastic pollution
We need to do more than cut back on plastic if we are to avoid a looming disaster: we need to find new uses for the material, along with ways to destroy it without ruining the environment
The world has a big plastics problem, and it’s about 5-billion tons big. It’s choking the oceans, clogging the waterways and polluting the earth; it’s even in the air we breathe. And the plastic is not going anywhere: it takes about 400 years to degrade and, even then, it breaks down into ever-smaller fragments that permeate the environment.
In a landmark 2017 study for the journal Science Advances, researchers found that of the 8.3-billion tons of plastic produced since the introduction of the material in the 1950s, 6.3-billion had become plastic waste by 2015. Of that, just 9% had been recycled, 12% had been incinerated and 79% (about 5-billion tons) was languishing in landfills around the world.
According to National Geographic, about 40% of all plastic produced is for packaging purposes; it’s used once and then discarded.
But while cutting out such single-use plastics may reduce our growing plastic footprint, that’s not nearly enough to address the problem.
Neil Stacey, a scientist and senior researcher at Unisa’s Institute for the Development of Energy for African Sustainability, says even if we were to cut every major use of plastic — itl plays a large role in the construction and textile sectors, for example — and turn off the factories overnight, the problem will persist for centuries as more of the plastic already produced enters circulation.
It means both the need to find new uses for single-use plastics — to extend their utility — and ways to destroy the substance after it has outlived its usefulness. Scientists and companies around the world are working on this.
International sportswear brand adidas, for example, has partnered with the organisation Parley for the Oceans to tackle the pollution of the seas specifically. Over the past four years the brand has developed its adidas Parley range of shoes, made from plastic debris collected from the oceans and recycled to produce the sneaker.
Adidas has also developed the Futurecraft Loop, which is said to be the world’s first 100%-recyclable plastic sneaker. Everything about the shoe, from the sole to the laces, is made from thermoplastic polyurethane. The various elements are fused by heat, so no glue or stitching is required, which means the shoe can be turned into plastic pellets once it’s reached the end of its life, and can be recycled to form a new Futurecraft Loop sneaker.
Back home, the Kouga municipality is piloting an innovative plastics project. The Eastern Cape town of Jeffreys Bay is set to become home to the first "plastic road" in SA, with a surface made of a composite of plastic and other materials. Local civil engineering and construction companies SP Excel and Scribante Construction are partnering with Scottish firm MacRebur to build a 1km trial road in the municipality.
According to MacRebur’s website, each 1km of plastic road is made from 684,000 plastic bottles or 1.8-million single-use plastic bags. These are processed into pellets, which displace a proportion of the bitumen in the conventional asphalt mix.
Vicky Knoetze, a member of the Eastern Cape provincial legislature, says the resulting product is expected to be stronger and more durable than traditional bitumen or asphalt roads; it is less porous — meaning fewer potholes will be formed — and can withstand greater heat.
But all plastic, even plastic roads, will at some point become landfill material, says Stacey. This is why research needs to focus on ways in which to rid the environment of plastic as well.
"A legitimate solution to the problem of waste plastic must be capable of eliminating what has been produced, along with plastic that is still being produced, and must also provide enough of a financial incentive to make the costs of collection and sorting affordable and to motivate rapid adoption on a global scale effectively," he says.
Stacey and his colleague James Fox have formulated processes that could completely convert waste plastic to either electricity or valuable chemical products. They have filed a provisional patent for one of these processes.
The researchers say high-temperature thermochemical conversion can produce hydrogen and carbon monoxide, a mixture known as synthesis gas, from the hydrocarbons that make up waste plastic. This gas can then be used in several chemical processes, including catalytic conversion to liquid fuels, and can produce electricity in a gas turbine.
The scientists are also investigating processes by which waste plastic could be used for processes such as smelting iron.
Unlike simple incineration, they say, these processes could completely eliminate waste plastic without toxic emissions. As an added benefit, as fuels they could emit less carbon dioxide than conventional materials such as coal.
In a paper published in scientific journal Energy, Stacey and Fox demonstrate that the commodity value of waste plastic as an energy material can exceed $300 a ton if used efficiently.