How Does Recycling Plastic Work?

Close-up of crushed plastic bottles

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Plastic Recycling came to fruition during the environmental revolution of the late 1960s. The idea to recycle products is as old as humanity when the first mother gave the younger child the worn clothes of his sibling. During World War II, the U.S. government asked the citizenry to recycle and reuse products like tires, steel, and even nylon, but it wasn't until the groovy era and culture of the 1960s, that people's minds turned toward counter-cultural ideas including salvaging the ever-increasing numbers of plastic containers foisted on the American consumer.

The First Plastic Recycling

The first plastic recycling mill for Waste Techniques was built in Conshohocken, Pennsylvania, and began working in 1972. It took several years and a concerted effort for the average Joe to embrace the recycling habit, but embrace he did and continued to do so in increasing numbers. Plastic recycling is unlike glass or metal processes due to the greater number of steps involved and the use of dyes, fillers and other additives used in "virgin" plastics.

The Plastic Recycling Process

The plastic recycling process begins with sorting the various items by their resin content. The chart on the right shows the seven different plastic recycling symbols marked on the bottoms of plastic containers. The recycling mill sorts the used plastics by these symbols and may perform an additional sort based on the color of the plastic.

Once sorted, the plastics are chopped up into small pieces and chunks. These pieces are then cleaned to further remove debris like paper labels, residue from what was inside the plastic, dirt, dust, and other small contaminants.

Once cleaned, the plastic pieces are melted down and compressed into tiny pellets called nurdles. Once in this state, the recycled plastic pellets are now ready to reuse and fashion into new and completely different products, as recycled plastic is hardly ever used to create the same or identical plastic item of its former self.

Does Recycling Plastics Work?

In a nutshell: yes and no. The plastic recycling process is fraught with flaws. Some of the dyes used in creating the plastic can be contaminated and cause an entire batch of potential recycling material to be scrapped. Additionally, there is still a large percentage of people who refuse to recycle. Thus the actual numbers of plastics being returned for reuse are roughly 10% of what is purchased as new by consumers.

Another issue at stake is the fact that producing recycled plastic does not reduce the need for virgin plastic. However, plastic recycling can and does reduce the consumption of other natural resources like timber, due to its use in making composite lumber and many other products.

Common Recycled Plastics

  • Polyethylene Terephthalate (PET, PETE): Excellent clarity, strength, toughness, and barrier to gas and moisture. Commonly used in soft drinks, water, salad dressing bottles, and peanut butter jars.
  • High-Density Polyethylene (HDPE): Excellent stiffness, strength, toughness, resistance to moisture and permeability to gas. It is commonly used in milk, juice, and water bottles; trash and retail bags.
  • Polyvinyl Chloride (PVC): Excellent versatility, clarity, ease of bending, strength, and toughness. Commonly used in juice bottles, cling films, and PVC piping.
  • Low-Density Polyethylene (LDPE): Excellent ease of processing, strength, toughness, flexibility, ease of sealing, and a barrier to moisture. It is commonly used in frozen food bags, freezable bottles, and flexible container lids.

Plastics Recycling: Conclusion

Any effort helps when it comes to saving our environment. Plastic recycling has come a long way since its inception in Pennsylvania and continues to make strides in reducing the amount of waste in our landfills. It's funny that before the push by manufacturers to use plastic containers, they used glass, paper, and metal products to hold and store their goods. These are all materials that were easily recycled, and yet we walked away from them for some largely insignificant reasons.