Is an age-old chemical process the solution to today’s plastic waste problem?

Let me state at the outset that plastics, per se, are not the problem. Plastics are essential to modern life and provide countless benefits in transportation, healthcare, food storage and so much more. The real problem is plastic waste. Environmentalists and NGOs have long warned of the impact that plastic waste has on land, water and air. Today, regulators, industries and society alike recognize the need to limit waste and identify solutions.

plastic trash

Recent years have seen heightened interest in the potential for circular technologies to break, or at least mitigate, the adverse effects of plastic waste in the environment. However, these solutions can’t handle all types of plastic waste, especially plastics blended with other materials such as adhesives. And in many markets, the economics favor new-use or single-use plastics over recycling, while others lack the necessary collection and sorting systems. As a result, single-use flexible plastics, such as bags and packaging—which account for about 50% of all plastics consumption and half of total ocean litter—mostly end up being incinerated, landfilled or just thrown away.  

Boston Consulting Group (BCG; Boston) recently completed several comprehensive analyses of global waste markets, collection systems and recycling regulations, including business cases for mechanical recycling and conversion technologies. BCG examined the plastics-to-fuel (PTF) value chain, including an in-depth analysis of pyrolysis, a common PTF technology that uses heat in an oxygen-starved environment to convert plastic waste into synthetic oil and gas without emitting a lot of greenhouse gases. “We examined the costs of the pyrolysis process and its market potential as well as its environmental impact and shortcomings,” said Udo Jung, senior advisor to BCG and one of the authors of the study, “A Circular Solution to Plastic Waste.”

“Pyrolysis leads to liquid feedstock that can be used again to produce plastics, leading to a true circular solution,” explained Jung, citing BASF’s ChemCycling approach. “The quality of the plastic waste input and the specific pyrolysis technology determine whether the products can be used to produce plastics again or be used as fuel.”

BCG studied how various factors and trends play out in three types of markets around the world, ranging from largely unregulated and immature markets to highly regulated ones with well-developed collection chains. The analysis was reviewed by experts from the chemical industry, waste management companies, circular-economy organizations and academe.

Chemical recycling of plastics to fuel, or plastics regeneration, can fill a big gap on the disposal-reuse spectrum. The ultimate solutions will involve a combination of judicious consumption and disposal measures as well as the development of cost-competitive and environmentally friendly alternatives. Most observers would agree, however, that these changes are years away. In the meantime—over the next decade or two—circular solutions can be implemented to reuse or repurpose plastic waste in the most efficient way.

BCG’s main conclusion is that while the economics and business challenges vary, conversion technologies such as pyrolysis are economically viable in all the market types described in the study. In some, pyrolysis can have an immediate and substantial impact—it has the potential to treat up to two-thirds of the plastic waste generated in Jakarta, for example. In others, the business case is feasible only if governments act to make inexpensive and environmentally detrimental means of disposal—principally landfills—less financially attractive.

“There is a clear hierarchy from top to bottom of addressing the problem of plastic waste,” Jung explained to PlasticsToday. “Avoiding unnecessary plastic packaging is at the top of the hierarchy. Reuse is next, then mechanical recycling and the case for pyrolysis or chemical recycling, which is suitable for anything that can’t be mechanically recycled.”

Pyramid of plastic waste management from Boston Consulting Group
The pyramid of plastic waste management, courtesy Boston Consulting Group.
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PDF iconBCG-pyramid-pdf.pdf

BCG’s study noted that conversion into fuel or petrochemical feedstock can be realized through a variety of technologies, the most common of which is pyrolysis. Pyrolysis has some distinct advantages over other recycling and recovery technologies. It is adept at handling a variety of plastic types that mechanical-recycling centers typically reject. While pyrolysis uses heat, the only carbon dioxide it emits is from the energy source that generates the heat. As a result, its carbon footprint is much lower than incineration.

Santosh Appathurai, Principal in BCG’s Houston office and co-author of the study, told PlasticsToday that a pyrolysis chemical recycling process could be used to treat all plastics except PET and PVC. Flexible plastics are the most significant material for chemical recycling because they don’t go to mechanical recycling. “We have had examples of companies partnering in the collection and chemical recycling of flexible household plastic waste, like the Hefty EnergyBag program [with Republic Waste Services], in which non-recyclable plastic waste is collected and sent to a pyrolysis plant,” said Appathurai. 

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