The Evolution of Recycling

As a material, plastic is incredibly useful, but there are profound problems with how plastic is traditionally made and how it’s dealt with at the end of life. Here we explore the different types of plastic recycling methods and how they have evolved over 40 years.

Since the widespread popularization of plastics in the 1960s, global plastic production has ballooned. In 2022, the world produced an estimated 460 million tons of plastic, and production figures are projected to hit one billion tons annually by 2050. Yet only 9% of used plastic is recycled globally. 

The easiest option for plastic disposal has been – and continues to be – simply dumping it into landfills. Sadly, as a non-biodegradable product that has been shown to cause a variety of health problems as it decomposes, plastics are demonstrably unfit for any sort of landfilling method. Despite this, landfilling is still used as a “solution” for more than 70% of all plastic waste in the United States.

Separately, 15% of all plastic waste is sent to facilities for incineration, where it is burned to generate steam power. The environmental cost, however, far outweighs the benefit of new energy production since burning plastic releases both CO2 and toxic ash containing heavy metals.

As a material, plastic is incredibly useful. Plastic keeps our food safe, allows for the safe transport of medicines, and – in the form of polyester – is the most common ingredient in the majority of our clothing. Despite its usefulness, there are profound problems with how plastic is traditionally made and how it’s dealt with at the end of life. Here we explore the different types of plastic recycling methods and how they have evolved over the past 40 years.

Mechanical Recycling

Mechanical recycling came about in the 1970s and it’s what most people think when we hear “plastic recycling”: bales of plastic waste are sorted, cleaned, flaked, heated, and finally reformed as plastic pellets for new use. Over 90% of all legacy recycling facilities follow this process. 

But mechanical recycling is expensive. You have to sort the waste – first to separate plastics from non-plastics, a second time to separate the plastics by type, and often a third time by the recycling facility to remove any materials that the facility’s equipment cannot process. Multiple sorting rounds on this scale takes significant amounts of time, translating into substantial costs.

The other major drawback is downcycling, where the recycling process degrades plastic to the point that recycled materials have a lower quality than the virgin plastic from which they are made. Recycled plastics are often mixed with virgin plastic to dilute the downcycling effect, which undercuts the positive impact of recycling material in the first place. Even worse, after two cycles, almost all mechanically recycled plastics are landfilled or incinerated because they are of such low quality.

Chemical Recycling

Chemical recycling, a term covering diverse technologies such as pyrolysis, methanolysis, and glycolysis, represents an advancement from mechanical recycling. However, chemical recycling tends to be more resource-intensive compared to both virgin plastic production and conventional recycling. While the methodology differs from recycler to recycler, chemical recycling most commonly involves the use of significant heat in the absence of oxygen (pyrolysis) to decompose plastic waste.

Because this process requires less sorting, input costs are lower, resulting in a more favorable economics. Yet, chemical recycling is often even more energy intensive than both virgin plastic production and traditional mechanical recycling. The environmental impact is considered to be so significant that fewer than half of the states in the U.S. have passed legislation enabling the use of the technology.

Biological Recycling 1.0

Recently, a few industry players have begun to explore a third avenue of plastic recycling: a technology that uses bacterial enzymes to “eat” plastic waste.

In 2016, Japanese scientists discovered a bacteria – Ideonella sakaiensis – outside of a plastic recycling facility. As the only bacterium known to degrade plastic as its primary energy source, I. sakaiensis has garnered significant attention in recent years as an unexpected solution to the plastic recycling problem. Enzymes isolated from the bacterium opened up exciting possibilities to break down the molecular chains of plastic waste into their component parts for reuse, without the downcycling concerns of mechanical or chemical methods. Naturally, the discovery of I. sakaiensis was heralded as “a huge step forward” for recycling, with multiple companies racing to commercialize the use of this so-called “super enzyme”. 

Biological recycling improves on the carbon footprint of chemical processes by operating at low temperatures and pressures. The specificity of biology, where enzymes target the bonds that hold polyester together and do not act on the non-polyester materials in a waste stream, allows biological recyclers to produce higher-quality products compared to chemical processes. 

In the years that have followed, however, no company has been able to make the process efficient enough to be financially self-sustaining. These “super enzymes” are certainly effective, but they’re woefully inefficient, expensive to produce, and have not yet proven that they can adequately address textile waste streams (such as used clothing, rugs, bedding) – despite much promise to do so – due to the complicated makeup of the plastics in textiles.   

Biopure™: The next generation of biological recycling 

Biopure, PEI’s flagship innovation, sets a new standard for biological recycling and production of polyester waste. Our proprietary technology improves on the advancements made in biological recycling and transforms PET plastics into high-quality raw materials, mirroring the performance of virgin polyester but with a fraction of the carbon footprint. Operating at low temperatures and atmospheric pressure, Biopure distinguishes itself by using a gentle yet effective process, breaking down polyester waste into the building blocks of new polyester – PTA and MEG – without the energy-intensive demands of traditional recycling methods.

What sets Biopure apart is its ability to process a wide range of polyester waste, including textiles, packaging, and films. This capability not only significantly broadens the scope of recyclable materials but also ensures that the quality of the resultant products does not degrade over time. Consequently, Biopure facilitates a truly circular economy for plastics, where materials can be recycled indefinitely without loss of quality or performance. 

Biopure is not just an advancement in biological recycling technology; it’s a giant leap towards more sustainable and environmentally responsible new plastic production. By offering a solution that rivals the cost and quality of virgin polyester, we are paving the way for a future where plastic waste is a valuable resource, not an environmental or financial burden.