How Recycling Plants Process Plastics

Plastics have only been around for just over a century, but they’ve already woven into almost every part of our daily lives. From kids’ toys to food packaging, plastic is everywhere. In about 70 years, we’ve produced 8.3 billion metric tons of plastic, with around 6.3 billion metric tons ending up as waste.

Unfortunately, only 9% of that waste gets recycled.

There are several reasons for this, but the good news is that technology is improving, and changes in how we use and manage plastics are making recycling more efficient and effective.

Why is plastic recycling important and what are the challenges faced by the industry?

Recycling plastic is crucial for managing our current waste and for building a circular economy and zero-waste systems. These systems aim to cut down on waste and boost sustainability. Our habits around waste generation and disposal have serious social, environmental, and economic impacts. From microplastics affecting ecosystems to an estimated $2.5 trillion in damage to fisheries, aquaculture, and global well-being, the effects are clear.

However, tackling plastic waste isn’t easy. Many people still don’t fully understand the problem. Even though issues with plastic waste were raised as early as the 1960s, the plastics industry has often resisted real change. Recently, though, more people are seeking sustainable alternatives and learning about the importance of recycling plastic.

Today, both consumers and businesses want to recycle more, but there’s a lot of confusion about how to do it right. This often leads to contamination—like mixing non-recyclable plastics with recyclable ones or trying to recycle plastics that are dirty from things like adhesives, chemicals, or food. This contamination can cause recyclable plastics to end up in landfills instead.

Another challenge is the complexity of plastic products. Some items, like water bottles, are made from a single type of plastic (like PETE), which makes them easier to recycle. But many products use a mix of plastics or combine plastics with materials like wood or metal, making them tough to recycle. Sadly, these mixed-material products often end up being thrown away instead of recycled.

Despite these challenges, plastic recycling has improved a lot in recent years. The process can now be broken down into six basic steps.

The plastic recycling process steps

1. Collection + distribution

The first step in recycling plastics is collecting used materials from homes, businesses, and other places. This collection can be handled by local governments or private companies, with private companies often being a popular choice for businesses.

Another option is to drop off your plastics at community collection points, like recycling bins or facilities. These can be as simple as a bottle bank on a street corner or as involved as a local waste site with different areas for various types of recyclable and non-recyclable waste.

2. Sorting + categorizing

The next step in recycling plastic is sorting. Since there are many different types of plastic, recyclers need to separate them. They also sort plastics by things like color, thickness, and how they were used. Machines at the recycling plant handle this sorting. It’s a crucial step because it helps make the recycling process more efficient and keeps the final products clean and uncontaminated.

3. Washing

Washing is a really important part of recycling plastic because it helps get rid of impurities that could mess up the whole batch. This step removes things like product labels, adhesives, dirt, and food scraps. Even though the plastic gets washed during recycling, it’s still important to make sure it’s as clean as possible before you throw it away or drop it off for recycling.

4. Shredding

Next, the plastic goes through shredders that chop it into much smaller pieces. These smaller bits are easier to process in the next stages and can also be used directly in other applications. For example, they might be mixed into asphalt or sold as raw material.

Shredding the plastic into smaller pieces also helps to spot any remaining impurities. Contaminants like metal, which washing might have missed, can be easily picked up with a magnet at this stage.

5. Identification and separation of plastics

At this stage, the plastic pieces are tested for their type and quality. First, they are sorted by density. This is done by floating the plastic pieces in a container of water to see how they behave. Next, they go through an “air classification” test to check their thickness. This involves putting the shredded plastic into a wind tunnel. The lighter, thinner pieces get blown around, while the heavier, thicker pieces stay put at the bottom.

6. Extruding + compounding

In the last step of plastic recycling, the shredded plastic is turned into something useful for manufacturers. The plastic pieces are melted down and then formed into small pellets. Keep in mind that not all types of plastic can be processed at the same facility, so sometimes different grades of plastic are sent to other recycling centers to finish the job.

Also Read: Creative Projects to Reduce Plastic Waste

The different types of plastic

When it comes to recycling plastics, it helps to know about the different types. You might have seen numbers on plastic products; these numbers actually tell you what kind of plastic it is, not just that it’s recyclable.

Here’s a quick guide to the seven plastic types:

1. PETE (or PET) – Polyethylene Terephthalate
This is a common plastic used in things like food containers and drink bottles. PETE is widely recycled.

2. HDPE – High-Density Polyethylene
HDPE is used in sturdier products like detergent bottles, milk jugs, and some toys. It’s also widely recycled.

3. PVC – Polyvinyl Chloride
PVC is used in things like pipes, flooring, and signs. It’s not commonly recycled due to its toxicity when processed.

4. LDPE – Low-Density Polyethylene
LDPE is used in things like plastic bags and containers. It’s recyclable, but some products, like plastic bags, are often not recycled because they can clog machinery.

5. PP – Polypropylene
You’ll find PP in items like bottle caps and some clothing. It is recyclable, but processing centers often reject it due to issues during recycling.

6. PS – Polystyrene
Polystyrene is used in disposable food containers and packaging. It’s rarely recycled because it’s not cost-effective and requires more energy to process.

7. Other
This category includes mixed plastics and those not covered by the previous six types. Many of these are not recycled and require other waste solutions.

Plastic recycling faces challenges because, unlike glass and aluminum, plastics aren’t infinitely recyclable. Each time they’re recycled, they degrade and become lower quality.

But there’s good news! Recycling technology has improved a lot over the years, and innovations like chemical recycling are helping keep more plastics in the recycling loop. Plus, more alternatives to plastic are becoming available.

As people and businesses get better at recycling, we’ll see improvements in the process. Although we’re moving away from single-use plastics, recycling will still play a crucial role in managing waste and making sure we use resources wisely.