Recycling – How It Works


There you stand, in front of both a recycling and trash bin with a random plastic, metal, or paper object in your hand – wondering, is this recyclable? After a moment’s thought, you toss it in the recycling bin, after all, someone at the facility will sort it out.

An image comes to your mind, it is a large “Santa’s workshop” type of factory, with workers elbow deep in recycling material, carefully hand sorting the plastic bottles, cans, paper, and cardboard, then neatly compiling it into perfect piles.

Unfortunately, this fantasy factory where everyone is working feverishly to hand sort your recycling isn’t a reality. Recycling is actually sorted with the support of machines, technology, and equipment, each uniquely designed to capture specific types of material out of the recycling stream. All of this takes place at a Material Recovery Facility or MRF. MRFs have anywhere from 30 – 900 tons of recycling move through a day – there is no way this could all be sorted by hand!

There is still plenty of human power working to ensure your recycling is sorted, bailed, shipped, and turned into something new, but very few workers are actually sorting the material. Many individuals work on creating the technology and equipment, maintaining operations, selling the material, inspecting the bales, and educating the public. You can read more about the economic benefits of recycling here.

In order to really understand how the recycling system works, let’s get geeky with it and take a look at the entire system, along with how each unique piece of equipment aids in the process.

Weighing and Tipping

Before any of the material enters the facility, it is weighed. Most MRFs have a scalehouse, where giant scales weigh the truck and material together and then subtract the weight of the truck to determine how much material is coming into the facility. These numbers are important for both the municipalities or companies hauling the material and the facility processing it.

Once weighed, the truck empties its contents onto the tipping floor. The material is then hoisted onto a main feed conveyer belt, where it begins its journey through the facility. The first stop is usually a pre-sort, this is where humans (who are still smarter than machines) recognize and remove things that can damage equipment or injure people further down the line. These are items that should not be recycled at the curb – from Christmas lights to machetes, MRF operators have seen it all!

Paper and Cardboard

Paper and cardboard are removed with a “star screen.” This machine consists of a series of quickly spinning discs that kick up paper and other flat lightweight materials, removing them and allowing the heavier materials to fall in between to continue down the line.

Know What to Throw

Hoses, cords, clothes, wires, metal hangers, plastic bags and film, and other “tanglers” (link to tanglers blog) jam up the star screen, getting all tangled up in the discs. This slows down the entire recycling process, as workers have to shut down the equipment and clean off the discs – a dangerous and incredibly annoying task. Trust- this is way worse than getting those strings out of your vacuum cleaner!

Pretty sure you already know what to throw in your recycling bin? Check your recycling knowledge here.


A Density Separator removes glass from the stream by vibrating it through fine metal screens, then knocking it out with air knives or strong puffs of air (which does not sound nearly as cool).

Small objects, like bottle caps and shredded paper, can easily end up mixing in with these glass shards, making it harder to recycle the glass. Keep objects smaller than an index card out of your curbside recycling bin.

Steel and Tin

It’s magnetic! Ferrous metal, metal that contains iron, such as soup cans and tuna fish cans are picked up with a giant rolling magnet.

This magnet is not attracted to all types and only picks up steel and tin CANS, not scrap metal or other metal objects. These other items can actually damage the equipment and should be taken to a scrap metal recycler instead.


Optical sorters work like a giant eyeball by shining an infrared light on objects, that light bounces back sending a signal to the computer, which determines the type of plastic the object is made out of – when it finds what it’s looking for – it uses a puff of air to remove the material.

If a bottle contains liquids, the puff of air will not budge it and it won’t get recycled. All bottles and jugs should be completely empty before being tossed into your recycling bin. Please remember, just because something is plastic does NOT mean you can recycle it – no plastic toys, lawn chairs, or laundry baskets — plastic bottles, tubs, and jugs only.


Aluminum, which is unlike steel and tin, is separated from other recyclables using a technology called the eddy current. The eddy current (interestingly not discovered by a guy named Edward) is a rare Earth magnet that creates a force, similar to the one that occurs when you try to push together two opposing magnets, repelling aluminum cans to where they need to go.

Know What to Throw

Aluminum cans are one of the most valuable material we recycle and has the highest level of recyclability – which means it can be recycled over and over forever. When recycled, aluminum can become a new can on the shelf in just 60 days — saving 95 percent of the energy and water that would go into producing a new can from scratch or raw aluminum. Keep throwing those cans in your recycling bin!

Bailing and Shipping

Once all of the items are separated, they are baled (put together in like piles) and shipped, both domestically and internationally, to companies to make new packaging and products, completing the recycling life cycle.

It Takes A Community

There it is, the entire recycling system in a nutshell, well, almost. There is one part of the process we did not cover – you!

Ultimately, you are the first (and arguably most important) step in the recycling process. Without you tossing those discarded materials in the recycling bin, there would be no material to sort. This makes it critical that you know what to throw, in order to make the system work.

If the wrong materials enter the recycling system, they can damage equipment, harm workers, and cause an entire shipment to be rejected, wasting the energy and time that went into sorting and transporting them.

Pretty sure you already know what to throw in your recycling bin? Check your recycling knowledge on our online quiz.

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