By Jeremi Nuer
“Plastic can’t be recycled.”
It’s not a factual statement, but it might as well be. In 2021, only 5% — 3 of 51 million tons of plastic was recycled in the US (source). Compared to the 68% recycling rates of cardboard and paper, plastic recycling is severely dysfunctional.
The impact of this is severe—and not only for the marine environments that plastic can pollute and harm. Plastic is actually made from fossil fuels, and thus its production is an emitter of greenhouse gases. Every piece of plastic recycled helps combat the demand for newly produced, CO2 fueled plastic.
There are seven main plastic resin types. The two plastics that are widely accepted as recyclable are #1 (PET) and #2 (HDPE). These plastics have a ~30% recycling rate in the US. (source)
However, the remaining #3–7 plastics are comfortably labeled as ‘non-recyclable’ by the recycling sector. This is not to say that these plastics can’t physically be recycled (they can) but rather that the current system doesn’t support their recycling
Of these #3-7 plastics, Polypropylene (shorthand: PP; #5) is perhaps the most feasible to be recycled. Despite this, very little of it is recycled—some studies estimate the recycling rate could be ~1%.
This report attempts to provide a cohesive explanation of why PP (#5) plastic has such low recycling rates, and provide potential solutions as to what can be done to improve the current status of recycling PP. This report is focused mainly in California, but is applicable to the rest of the US.
This report is split up into six main sections:
At the end of the day, an MRF is a business—and business need to make money. For sorting PP to be profitable, an MRF must be confident that there will be sufficient supply of PP, and demand for recycled PP (rPP).
Polypropylene is a large industry. It can be found in packaging, medical applications, consumer goods, electronics, and the automotive industry. It was estimated that in 2018, ~7.5 million tons of PP plastic were produced in the US. Compare this to the ~10 million tons of HDPE produced in the US (a plastic which is commonly sorted by MRFs and meets the supply constraint), and there is not a great difference in terms of supply.
Furthermore, PP plastic is becoming more prevalent, especially as COVID re-emphasizes the importance of packaging (a large market for PP). According to Straits Research, the PP market is projected to grow at a CAGR of 3.8% until 2030.
Demand for recycled PP is similarly growing. As consumers become more insistent on sustainability for the things they buy, producers are pressured to incorporate recycled plastic into their products. Furthermore, the end markets for rPP are growing—the plastic is entering high value markets such as the packaging and food contact industry.