The Plastic Recycling Process

In 2022 over 5 billion pounds of plastic packaging was recycled in the U.S., driving jobs and revenue, reducing natural resource extraction and greenhouse gas emissions, and helping the country move towards a circular economy.

But how did those 5 billion pounds of plastic get recycled? What happens after someone tosses that plastic bottle or container into the recycling bin? Scroll down to follow this amazing journey.

Recycling Bin

• Whether a container is placed in a curbside recycling bin, a public recycling bin at the airport, or dropped off at a community recycling center, this is where it starts.

→ Tip: When the right material gets into the recycling bin, that material gets recycled! It’s important that we all know what can & cannot be recycled in our community. Check your community recycling website, use RecycleCheck with your zip code, or follow these general guidelines:

• In most communities, #1 PET bottles, #2 HDPE bottles, and #5 PP containers can be recycled.
• Empty any remaining food/product, rinse if necessary, and put caps back on bottles.
• Do NOT recycle plastic bags or any flexible films (think shrink wrap, zip lock bags) in curbside bins unless a program specifically calls for them. Those should be collected and returned to store drop-off locations.

Haulers

• Haulers collect post-consumer materials from the curbside recycling bins, and take it to a material recovery facility (MRF)

→ Tip: Occasionally haulers use one truck to collect both recycling & trash. In this situation, it may look like a garbage collector is tossing carefully separated items into the same big pile. But there is actually a divider in the truck, and trash goes on one side and recycling on the other. Materials stay separate so that those recyclables can be sorted and reprocessed into new materials, and avoid the landfill.

Material Recovery Facility (MRF)

• A material recovery facility (MRF) sorts through all the recyclables and divides them into categories like aluminum, paper, and different types of plastic. The goal is to sort and bale each material so that it can be sold to the correct market.


• 1. TIPPING FLOOR
• All the recyclables are tipped out of the trucks onto the floor in a giant pile, and then loaded onto a conveyor belt to start their journey. This is a mix of plastic, paper, metal, glass and more.


• 2. PRE-SORT
• The materials on the conveyor belt then go through pre-sorting, where MRF workers pull out non-recyclable materials which could be anything from electrical cords to food to bowling balls!
  • → TIP: These items are called contaminants, and they do not belong in the recycling system. They not only increase the cost of recycling, but can also injure workers and machinery. This is why it’s important that residents and businesses follow guidelines of what can and cannot be recycled. It’s also a reason to avoid “Wishcycling,” which is when people put the wrong materials into the recycling bin, hoping that they will be recycled instead of trashed.
• Workers also remove a lot of plastic bags. Plastic bags should not be combined with other recyclables. They should be collected separately and returned to special drop-off locations, often located at grocery stores and other retail locations. Plastic bags get caught in machinery and need to be cut out with knives multiple times a day, leading to safety, productivity, and profitability challenges.


• 3. MATERIAL SORTING
• Next comes a series of steps to sort materials first by size and shape, then material type.
• Large cardboard is pulled off the conveyer first, and then the flat, 2D paper materials float over the screens while the 3D containers fall down through the screen.
• Metals are sorted out based on their magnetic (steel) and conductive (aluminum) properties.
• Glass is crushed and then sifted, so that anything smaller than 2 inches will fall through, while the rest of the material continues down the sort line.
• Plastic is sorted into types (PET, HDPE and PP are the most common) using optical sorters.
• In this example, the optical sorter is programmed to look for PET plastic. When the sensor sees a PET bottle, a puff of air is released and moves the bottle over the divider while the rest of the material falls down.
• Though the optical sorters are relatively effective, in-person quality control is still needed to sort out contaminants.
• Some MRFs have installed robotic arms to sort plastic or other materials, particularly in the quality control area.


• 4. BALING
• After the plastic is sorted, it is baled into compressed 1000-1500 lb rectangular blocks and wrapped with wire. The bales are sold to recyclers (commonly referred to as reclaimers), who will process the material into recycled plastic.
• MRF’s decisions around what they can economically accept and process are based on their revenues and costs, just like any other business. The revenue from the sale of bales needs to cover the costs of sorting and processing those materials. The value of recyclable materials fluctuates and depends on many external issues including the price of oil, material shortages, and other economic factors.
• APR creates model bale specs for plastic, to support both the MRFs selling bales and the recyclers buying them.

Recyclers

The recyclers (sometimes called reclaimers) purchase pre-sorted bales of plastic, and the goal is to convert as much as possible into post-consumer resin (PCR) pellets or flake, which can be sold to companies to replace virgin plastic in new products.

1. CUTTING BALES. The bales are cut apart, and the material is pushed onto a conveyor belt.


2. MATERIAL SORTING. Even though the recycler is starting with pre-sorted bales, it’s important to do another sort to remove any lingering contaminants—such as glass or small metals. The material will be sorted into 3 streams: the intended plastic (high value), missorted plastic containers (medium value) and waste (negative value.) The amount of sorting and pre-processing depends on the type of plastic being recycled and the intended end use.


3. GRINDING. The material then goes into an industrial grinder, where it will be cut up into small pieces, called flake.


4. WASHING. The flake is then washed in hot water and detergent solution to remove surface dirt and dissolve any adhesives used to attach labels.




6. FLOAT/SINK TANK. Next, the material goes into a large tank of water to separate different types of plastic. Some plastics float and some sink. For example, caps attached to a soda bottle travel with the bottle during the sorting phase but are separated during grinding. The caps, often made of HDPE plastic, float to the top of the float-sink tank while the bottle, made of PET, sinks to the bottom of the tank. This separates the different types of plastics so they can be processed and recycled.


7. RINSING & DRYING. The separated flake is rinsed again and then air dried.


8. ELUTRIATION. Some plastic packaging incorporates thin layers of other materials to increase product shelf life. These thin layers can delaminate during the washing process. In order to remove and capture these, the flake is passed through an airstream.


9. DECONTAMINATION. If the material will be used for food-contact packaging, it will go through a decontamination process using vacuum and heat under low oxygen levels. This is required to receive a Letter of No Objection (LNO) from the U.S. Food & Drug Association for food packaging.


10. MELTING & FILTERING. The flake is then melted in an extruder, filtered to remove small solids, and processed with special equipment to turn it into pellets.

→ Tip: Sorting and recycling plastic packaging is a very intricate process. This is why it is critical for companies to think about designing packaging for recyclability from the start. The APR Design® Guide is a free, self-service tool that is widely recognized as the authority on how to design plastics packaging for recyclability in North America. APR Design® Recognition provides third-party validation that a component or packaging has met the highest criteria for recyclability according to the APR Design® Guide.

Manufacturers:

When companies choose post-consumer resin (PCR) for packaging, they are choosing to reduce virgin plastic production. This means less natural resource extraction and a significant decrease in energy use. When virgin plastic is replaced by recycled content, the energy saved can be as much as 70%.

When individuals, companies and governments choose to buy items made with recycled plastic vs. virgin plastic, it creates the pull effect we need to keep our recycling system going. There needs to be a demand for recycled products for all the companies along the supply chain to participate. Choosing and supporting recycled plastic is critical.

Don’t forget-- if it’s recyclable, and your program accepts it, remember to throw it in the recycling bin when empty.