Real-world solutions to the plastic waste challenge – Plastics Today

During the summer of 2018, China made an announcement that would turn the recycling world upside down: It would no longer accept recycled materials from the United States and Europe. Up until that time, China had been accepting some 45% of the world’s plastic waste imports. Now, the world’s most developed countries would have to figure out—and quickly—what to do with the stacks of bales of mixed plastics and other recyclate.

It didn’t happen fast enough, however, and recycling companies were soon looking at mountains of plastic waste with nowhere to put them except in landfills. Much of the waste plastic has been shipped to Malaysia, which has started its own crackdown on imports of waste plastic from America and shut down illegal recycling facilities that have become dumping grounds for material nobody wants. Other Southeast Asian countries, including Thailand, Vietnam and India, are also taking steps to restrict the import of foreign plastic waste.

Much of the plastic waste being shipped to foreign shores from the United States and Europe was hard-to-recycle plastic and, even if it could be recycled, there was no market for it. The bales of recycled plastic—much of it mixed materials that would be impossible to sort—were dirty and not fit for turning into new flake to be sold back to companies to make products containing recycled material content.

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How did we get into this mess? It all seemed so easy at first, when the Plastics Industry Association (PLASTICS), then known as the Society of the Plastics Industry (SPI), developed an ingenious method for recycling plastics—chasing arrows with a number from one to seven in the middle indicating that this item could be recycled. The only problem was that numbers three through seven could not really be recycled. Only #1 (PET) and #2 (HDPE) were easily recyclable into material that converters demanded for new, recycled-content products.

However, instead of giving priority to #1 and #2 plastics, recycling systems in the United States went to the “single-stream” method, in which huge recycling bins were set up in neighborhoods where people could put all their waste: Plastic, paper, cardboard, glass and metals. Curbside recycling programs, which made consumers feel good about recycling, weren’t much better. Single-stream recycling soon became a huge, dirty mess that resulted in some 25% of the materials collected in the blue curbside bins being sent to landfills, and that is a low estimate. Some say that it’s closer to 70%, a result of China and many other countries refusing to accept recyclate they cannot economically reprocess.

This dilemma created the development of innovative technologies to try and solve the problem of what to do with the plastics that can be recycled but aren’t. Attempts are also being made to recycle difficult-to-recycle plastics. Taking a look at the various methods currently being used and why they are not working, as well as newer schemes that are being developed to address the issue might help us see where and why the system is failing.

Mechanical recycling

What it is: Mechanical recycling is a method that involves collection, either via curbside pickup or neighborhood recycling bins; manual sorting of the various materials at a municipal recycling facility (MRF); baling the #1 (PET) and #2 (HDPE) plastic; and shipping it to be cleaned and reprocessed into flake for use in new bottles, jugs, containers and so forth.

Pros: Curbside pickup is handy and easy for the consumer to recycle a variety of plastics in one bin.

Cons: Single-stream recycling means that everything is put into one bin and much of the plastic material is contaminated, often making it unfit for further recycling. Consequently, much of the post-consumer plastic recyclate ends up going to the landfill.

Complexity has been the bane of mechanical recycling. It involves curbside collection of single-stream materials, mostly manual sorting of multiple types of plastics, extensive use of resources to clean and reprocess the most recyclable plastics (PET and HDPE), and the problem of how to reprocess co-mingled plastics. That complexity has also resulted in limitations to the mechanical recycling method, causing people to lose faith that recycling can truly be a viable solution. This will inhibit even the most recyclable plastics from being recycled even as global brand owners’ goals cite “recyclability” as their primary sustainability effort. While nearly all brand owners have embraced recyclable packaging as a goal, we’ve discovered that just because packaging is recyclable doesn’t mean it will be recycled. Only a small percentage—some say 8%, others put the number as high as 30%—of recyclable packaging is actually recycled. There is much misunderstanding about recycling:

  • What is recyclable?
  • What materials are in demand to use as recycled content?
  • What is the best way to recover the high value of plastic materials without incurring tremendous cost in money and natural resources?

Municipal recycling facilities, aka MRFs, are dirty, dangerous places where people stand beside fast-moving conveyor belts snatching usable recyclable items from a co-mingled mess. Injuries such as cuts and scrapes and even smashed hands are common at these facilities. Needlestick-related injuries occur at the rate of 2.7 per 100 workers, according to a 2018 report from the Environmental Research and Education Foundation and the Solid Waste Association of North America. Fifty-three percent of facilities see needles daily and more than half find needles mixed in with plastics. Some recycling operations have implemented automated recycling, in which vision systems are programmed to automatically recognize plastic that can be recycled, kicking it to another conveyer to be saved while the rest goes into a truck headed for the landfill.

Not only is mechanical recycling labor intensive if done manually or expensive when automation is used, it is resource intensive. The plastics industry forgot to educate consumers that recycled plastic items have to be clean—free of labels, food and debris. Adhesive or glue-applied labels have to be washed off in a hot water and chemical bath to remove every bit of the unwanted material. Given that potable water is one of the earth’s most valuable and increasingly scarce resources, using it to remove labels and glue from plastic bottles headed for recycling doesn’t seem to be the most prudent use of that resource.

Automating the collection and sorting processes continues to be the Holy Grail for a whole lot of companies in an attempt to solve the problems that remain surrounding recycling. In March 2019, Christopher Mims pointed to this problem in the Wall Street  Journal in an article titled, “The ‘Internet of Trash’ Aims to Sort Out Our Recycling Mess.” He enumerated the problems that exist in our industry today when it comes to recycling: Virgin resin that is cheaper than recycled resins; contamination of good recyclable plastic that often has to be relegated to landfills; and the higher cost of recycled plastics due to the cost of cleaning the bottles and containers and removing labels and other contaminants. All of this simply makes recycling—which started out as a simple, good idea—a costly nightmare.

Mims’ article dealt with many of the various schemes that are being tried, such as Waste Management’s method of using “three different kinds of robots working alongside humans to pull contaminants out of a variety of waste streams” and “older systems that blow unwanted items off a conveyor belt with puffs of air.” He noted that Waste Management has partnered with a “startup called Compology, which makes dumpsters ‘smart’ by sticking internet-connected cameras in them” to control accidental contamination of recyclables by alerting haulers that the dumpster is contaminated.

Besides robots and vision systems, artificial intelligence is being employed to help with recycling. An article in Forbes from April 4, 2017, noted that in 2011 Finnish company ZenRobotics came up with a system that was a combination of computer vision, machine learning and artificial intelligence to run synchronized robotic arms to sort and pick recycled materials from moving conveyor belts.

Processing the most easily recyclable containers—PET water bottles and HDPE milk/juice/water jugs—is one thing. What to do with the other five “recyclable” but, in reality, hard-to-recycle plastic materials? There are several answers.

Read the rest of this article, which discusses the pros and cons of various programs and technologies for solving the plastic waste dilemma, including returnable packaging schemes, chemical recycling, pyrolysis and waste to fuel, by downloading this free PDF.