So, you threw a plastic bottle in the recycling bin. Congratulations—you recycled! Or did you? It’s easy to move on and forget about that plastic bottle. But there’s a lot more to the overall recycling process than you may think. After all, recycling takes a village—and a lot of technology.
Have you ever wondered about what happens to your recycling after it leaves the house? Each item put out for recycling only starts its journey once thrown in the bin. After it’s picked up curbside, it begins the laborious process of being turned into something else.
But how does the process pan out? We consulted recycling experts to get to the bottom of it.
What Happens to Your Recycling?
Recycling is the process of converting waste materials into new materials and objects. To do this, recycling often requires both machinery and employees to correctly sort recyclable items based on the material they’re made of. This includes paper, plastic, glass, metal, and more.
But how does the recycling process work? Alex Dubro, a sustainability consultant and member of both the Society of Plastic Engineers (SPE) and the Solid Waste Association of North America (SWANA), shared the ins and outs of the process.
"Recycling is better considered 'mechanical recycling' because what you put through recyclables do not undergo any chemical changes until after they leave the material recovery facility (MRF) in bales," Dubro says. "Your recycling is picked up by either your city’s sanitation workers or a private company. If you’re a resident, the city does; if a company, a private company like Waste Management will pick up."
From there, the recycling is transported to the MRF where it will be sorted. An MRF falls under one of two categories: dirty or clean. To fully understand the start-to-finish process of how something is recycled, it’s important to know which category your waste falls under.
Dubro says: "[Once] it is brought to the MRF, which may be either 'dirty' or ‘clean,' [it’s] dumped onto the tipping floor. Dirty MRFs will accept all your waste and source it separately; whoever disposes of the trash doesn’t do any recycling. Clean MRFs only accept recycled waste."
We also consulted Lauren Cutlip, business development and outreach manager at the Recycling & Disposal Solutions of Virginia. Cutlip says trash gets sorted before entering the MRF equipment.
"When the driver completes their route, they arrive at the [MRF] to be weighed in on the scale before unloading the recyclable materials onto the tip floor," Cutlip says. "Then a loader operator will scoop the materials and fill a drum feed or hopper where the items are mixed up and brought to the presort belt where staff looks for [non-recyclable] items that could damage equipment or contaminate the end product (including wood, clothing, plastic bags, scrap metal, and food waste).”
Most facilities use both machines and human sorters, known as pre-sorters, for this process. According to Cutlip, pre-sorters wear gloves and face masks and pull non-recyclables off the conveyor belts.
Rosie Briggs, community education & engagement manager/Eco-Leaders network manager at EcoCycle, says these non-recyclables and oversized items usually get removed to avoid machine malfunctions.
"Each MRF is designed differently, but typically the recyclables are loaded onto a conveyor belt first to go for the first screening, in which oversized items are pulled off the line so they don’t jam up the machinery later on," Briggs explains. "After that, cardboard is sorted out, and then fibers (paper and cardboard) are separated from containers. From there, the fibers are sorted by grade, and then the containers are sorted into glass, aluminum, steel, cartons, plastic #1, plastic #2, etc."
What Is the Sorting Process?
Next, recycling goes through a sorting process—a process that relies heavily on machinery.
According to Cutlip says: “The materials travel through a series of mechanical sorting steps, which in the case of the RDS Roanoke single-stream facility include an OCC screen where cardboard travels up onto its own conveyor, a fine screen where glass drops out, a news screen where 2D paper is separated from 3D containers, an optical sorter that pulls out PET bottles, an overhead magnet for steel and tin cans, AMP robots that pull off HDPE containers, and—finally—an eddy current that repels aluminum cans into their designated bunker."
As each of these materials is sorted out, Cutlip says they get baled and wire-tied to be stacked by a forklift in the facility until a driver arrives to transport a load of the material to be reprocessed. Most of the magic happens on the conveyor belt.
"Once on the conveyor belt, it goes through source separation, depending on items that can be baled together," Dubro adds. "Those items are usually metal (e.g. aluminum), plastics (i.e. the acceptable ones), glass, and fiber (i.e. paper). "The process for doing so is very rigorous—to separate metals, for instance, eddy current separators remove non-ferrous (e.g. copper, aluminum) materials."
This separation process is crucial because different markets purchase different materials.
"Sorting in the MRF is important because each material is sent to a totally different market," Briggs says. “Each market is buying a specific material to physically turn it into a new product, so they’re looking for bales of only that material."
Because MRFs rely significantly on sorting technology to do most of the work, the process must be as efficient as possible.
"The technology has improved tremendously over the past century, and non-recyclables (composites and hard-to-recycle materials) are again being considered for chemical recycling (e.g. gasification, pyrolysis)," Dubro says. "There’s also a conversation to be had about medical waste and e-waste. The latter is complicated because e-waste is usually composed of both plastics and metals. Source separation won’t do anything, which is why e-waste is collected separately."
However, technology doesn’t always eliminate the need for pre-sorters.
"We’re continually pulling contaminants by hand throughout the sorting process," Briggs adds. "We also try to pull items that have been recycled that shouldn’t have been. For example, a Styrofoam cup."
Once the sorting process is complete, materials are sent off to manufacturers where they can start new lives as recycled, repurposed items.
What Happens to E-Waste?
E-waste is a separate category that requires its own set of rules. Electronic waste can't mix with typical recyclables because it not only contains plastic but also possesses toxins like mercury and lead. Therefore, e-waste must be properly disposed of. Otherwise, you risk harming the employees who handle it, as well as contaminating the environment.
Evelyn O’Donnell of GreenMouse, Inc. Recycling told us the step-by-step process for recycling e-waste. After receiving the e-waste from customers, recyclable e-waste is brought to the warehouse to undergo the sorting process. Common sorting categories include—but are not limited to—TVs, monitors, printers, computers, laptops, cell phones, wires, and cables.
"We place the sorted items into designated Gaylord boxes or pallets," O’Donnell says. "All collected products, based on the category, are sent downstream for sale as scrap or sold wholesale to be refurbished or repaired. Most often computers, servers, laptops, monitors, and cell phones that are not obsolete are given a second life."
What about your data? If you're worried about what happens to any personal information that may be left on your devices, many e-waste recyclers give you the option to have it removed: "For laptop, computer, and server recycling, it’s important that we ascertain from our customers if they want to have the hard drives removed and destroyed, which is a service we provide,” O’Donnell says.
Do a quick Google search to see where you can recycle e-waste in your particular area. Many private companies have the option, as well as retailers like Best Buy. Typically, this type of recycling does come at a cost. For more information on how to recycle electronics, click here.
What Is Robotics Technology in Recycling?
At some facilities, AI-guided, robotic sorting systems are used in the sorting process. That renders pre-sorters almost unnecessary, as the technology is practically autonomous.
"The robotics technology is able to detect and retrieve a variety of materials without needing a full-time employee standing there grabbing items off of the sort line. A position that's very difficult to fill and retain long-term, plus comes with the ergonomic challenges of the repetitive picking task and other strains of the job,” Cutlip says. "At the RDS Roanoke Single Stream Facility, AMP's robotics systems are currently used to pull contaminants like plastic bags off of the mixed paper stream and to pull out HDPE containers and drop them into their designated bunker, as well as retrieve any PET bottles missed by the optical sorter."
How does it work? These robots use camera vision systems, Artificial Intelligence, compressed air, and pneumatic arms to identify what isn't recyclable and then remove it from the conveyor belt.
"They're always learning and improving when it comes to the types and quantity of material they're able to pull from the recycling stream," Cutlip adds.
The Difference Between Single- and Dual-Stream Recycling
Not all recycling facilities are created equal, but they can largely be categorized into two main umbrellas: single-stream and dual-stream recycling.
Single-stream recycling refers to a recycling method in which all kinds of materials can be mixed into one avenue: metal, paper, plastic, and other various containers. With single-stream, recyclables don’t have to be sorted by the depositor. However, an issue with single-stream recycling is the increased likelihood of contamination.
Alternatively, dual-stream recycling contains a more complex system for the depositor. Users are required to separate recyclable items by subcategory. This means putting paper in one bin, and commingled containers (plastic, glass, and metal) in another.
This introductory sorting phase is more accurate, which is why many recycling experts find it useful. And even still, what doesn’t belong ends up on a conveyor belt for either technology or an employee to take off. However, a significant advantage to dual-stream recycling is that it separates recyclable items from the start rather than halfway through the process.
How to Help the Recycling Process
Of the three R’s—reduce, reuse, and recycle—recycling seems to be the one most people remember. Recycling keeps getting easier thanks to the help of technology. However, the recycling process as it currently stands still has its issues, so remember—there's always room for improvement.
1. Know Your Town's Recycling Rules
Each city has its own recycling rules and regulations. As a consumer, you can learn which plastics and metals can’t go in the standard recycling stream. Check out your local recycling rules to ensure your waste actually gets recycled.
"There's a lot of confusion around what plastic is recyclable, largely because manufacturers of packaging put that big chasing arrows symbol on anything that can somewhere, somehow, be recycled," Cutlip says. "This doesn’t mean it can be accepted in your single- or dual-stream household recycling program. A huge example of this is tanglers, often in the form of plastic bags or film wrap. These should be brought to a designated store drop-off location so that they don’t tangle in the machinery at a recycling facility."
2. Find Local Drop-Off Locations
As Cutlip mentions, certain items—plastic bags, film wrap, or anything that has a tendency to get tangled in machinery—can be brought to a designated drop-off location. That way, these items don't cause problems in recycling facilities. You can find local drop-off locations for plastic bags and other tanglers.
"Same goes for scrap metal or metal appliances (pots, pans, microwaves, etc.) and even clothing," Cutlip adds. "You can find scrap metal facilities, donation drop-offs, and other places that will gladly take your items, but they don’t belong in the typical MRF where they can damage equipment, contaminate bales of product, and create more work for sort line staff."
3. Know the Difference Between Plastics
Another effort you can make to improve the efficacy of recycling is to learn what kind of plastic you’re using. Once the plastic recycling symbol or number is identified, you can determine how to properly recycle the plastic. Plastics are labeled 1 through 7, with each category identifying how the plastic can be disposed of.
"We can all do our part to find out the locally-accepted materials for recycling, for example, which number and types of plastic containers," Cutlip says. "Numbers 1 and 2 bottles and jugs are most commonly recyclable. It can vary quite a bit depending on what your local recycling facility has the equipment to process and whether there is enough volume and consistent, high-value end markets for the products."
4. Clean Your Recyclables
Last but not least, Cutlip recommends cleaning your recyclables before putting them in the recycling bin. This is especially important for food containers like takeout boxes. Plus, it prevents odors, molds, and pests and makes the recycling processer run a lot smoother at the facilities.
