Soft plastic, not fantastic: what to do with Australia’s bread bags and chip packets | Plastic

IPlastic confetti is liquefied in a south-west Melbourne warehouse. Amid the hum and beep of machinery, a table displays shredded soft plastics: colorful flakes of empty potato chip packets, garbage bags, and clear bread bags. The mound is located next to two oil flasks; that’s what the plastic will become. One is light, like olive oil. The other is as dark as tar.

The goal, says Logan Thorpe, manager of special projects for APR Plastic, is a “closed loop” of advanced recycling. Plastic waste is turned into oils, which turn into clear pellets resembling rock salt pellets, which can then be used to make more plastic.

There is a synthetic, but not unpleasant, smell in the air. In an open shipping container, a shredder breaks the soft plastic into 10-15mm flakes. These are fed through a dryer and then into an extruder, a machine that heats the flakes to a consistency Thorpe describes as “hot bubblegum, almost sausage-like.” Finally, the plastic undergoes a process known as pyrolysis: it is heated without oxygen, at temperatures up to 500°C, producing two types of oil, some gases, and carbon, an ashy carbon residue.

The machine is a prototype capable of processing up to a ton of soft plastics a day, Thorpe says. Early next year, APR will be converted to a commercial machine that can handle five tons per day, with a corresponding daily output of about 5,000 liters of oil. APR sends the oil to a partner company for processing into pellets.

In November, the federal government signed up to the international High Ambition to End Plastic Pollution Coalition, which aims to recycle or reuse all plastic waste globally by 2040.

Australia has also set a goal of making 70% of plastic packaging recyclable or compostable by 2025. At the current rate, it is unlikely to reach that target. A report published last year by the Australian Packaging Compact Organization (Apco) found that in 2020, only 16% of plastics were recycled. The soft plastic recycling rate was even lower: 4%.

The advanced recycling trial in Melbourne is part of the National Plastics Recycling Scheme (NPRS), a soft plastics program run by the Australian Food and Grocery Council. The NPRS aims to recycle an additional 190,000 tons of plastic a year, about a third of the soft plastic waste that currently ends up in landfills.

Trials are underway until March in six local government areas in Victoria, New South Wales and South Australia. The program involves the collection of soft plastics at the curb and is not affected by the REDcycle suspensionthat until its collapse was that of Australia largest consumption scheme for soft plastics, with collection points in almost 2,000 stores.

“It’s no secret that soft plastic has posed a particular challenge due to the complexity of collecting it and finding enough end markets for reprocessing,” says Apco CEO Chris Foley. “While the REDcycle system provides an effective solution to the first part of this problem, the recent pause in operations was due in large part to a lack of end markets for this material. This is a key challenge for the industry to overcome.”

How is plastic recycled?

Throw an empty milk carton or tub of ice cream into curbside recycling, and where does it go? The contents of your container are taken to a materials recovery facility, where various machines separate the mixed recyclable materials into different streams: aluminum, cardboard, plastics, etc.

The plastics are then taken to specialized facilities or shipped abroad. Much of Australia’s plastic was exported to China until 2018, when stopped accepting foreign waste. Other countries, mainly Indonesia and Malaysia, have been hardest hit since then. In 2020-21, Australia exported 124,000 tonnes of plastic waste, down from the annual peak of 203,000 tonnes in 2015-16. Since July, the export of mixed plastics has been banned.

Today, virtually all commercially recycled plastic is mechanically recycled: waste is melted down into an amalgam of plastics that is then transformed into new items, such as bollards.

Most soft plastics are made from polyolefins, a group of polymers that includes polyethylene and polypropylene. Soft packaging often contains multiple layers of different plastics, combined to create specific qualities, such as strength or an oxygen barrier, to extend the shelf life of food products.

Soft plastics are difficult to recycle because they interfere with mechanical recycling machinery, says Dr Deborah Lau, who leads CSIRO’s End Plastic Waste mission. “The inability to easily recycle soft plastics with mechanical recycling is not due to their chemical nature, but rather their physical form.”

The ongoing trials at APR are an example of advanced, or chemical, recycling.

“The heat and the absence of oxygen break down the polymer chains into smaller building blocks,” Lau says. “That produces a liquid that is a mixture of small hydrocarbon molecules [the main components of crude oil]. Those molecular building blocks can be separated and then used as the basic raw material to create new plastics, what are called ‘virgins.'” (Globally, about 99% of plastics are derived from fossil fuels).

Plastic pyrolysis is operating on a commercial scale abroad, including in Europe and the US. In March, US waste management company Brightmark announced it was building a plant in the town of Parkes, New South Wales, which, he said, could process 200,000 tons of plastic waste a year. “Pyrolysis is not a new technology,” says Thorpe. “It just hasn’t been perfected in energy efficiency and quality oil production until now.”

Criticism and controversy

The technology is controversial: some critics they’ve called it a greenwashing tactic that tricks the public into thinking more plastics are recycled than is actually the case. A US report published in May found that since the rise of advanced recycling in 2018, plastic recycling rates in the US have dropped from a high of 9% to less than 6%.

others have criticized the focus on plastic waste as distracting from existential threat of the climate crisis. researchers They have pointed out that plastic is less of a threat to the oceans than climate change or overfishing.

Generating high temperatures requires a high energy input, and pyrolysis is not emission-free: some gases are produced in addition to crude oil, which can be burned to power the heating process. But life-cycle analyses, Lau says, have shown that fewer emissions come from plastic recycled through pyrolysis than from virgin plastic, “because the carbon is actually recirculated, not from fossil fuels.”

Alternatives to pyrolysis include hydrocatalytic decomposition -which heats the plastic with water, in the absence of oxygen-, a technique used by the Australian firm Licella, which last week announced a partnership with global packaging company Amcor for a proposed advanced recycling plant in Melbourne.

Even with advanced recycling, plastic is not infinitely recyclable, says Professor Kalpit Shah, a chemical engineer at RMIT. There comes a point after multiple cycles where it reaches an “end of life” stage.

“Over time, it can lose its mechanical strength or certain chemical or physical properties,” he says, as a result of impurities, for example. At this point, it cannot be recycled into any more plastic, but it can be used in applications including roads, roof tiles, and steel.

Some say that focusing on collection and recycling is not enough to tackle plastic waste. Dr. Anya Phelan from the University of Queensland has order measures like “extended producer responsibility”: regulations that would require plastic manufacturers to pay for recycling and disposal of their products.

In it hierarchy Of the waste minimization strategies, “the first priority is really the overall reduction in the use of plastic waste,” Lau says, “where, if possible, unnecessary plastics can be phased out.”

“The fact that there has been such a strong reaction to the hiatus in the REDCycle system really shows that there is a huge appetite for recycling soft plastic to support mechanical recycling,” Lau says.

“The reaction to the pause…has been a really positive step in drawing people’s attention to understanding how the plastics recycling system works.”