Individual Practices
IN THIS LESSON
Understand the concept of recycling and why it might not be as effective as you’ve been led to believe.
12/24/25: Welcome to the brand new Sustainability course! This is one of the topics I’m most passionate about and I’m so happy to be able to bring it to you all. As a side note, I promise to find a higher quality image for the course header.
This lesson, for the first time, is paired with a post on the STEM+log!
I hope you enjoy!
What is Recycling?
Recycling is the process of collecting discarded materials and reprocessing them into new products instead of sending them to landfills or incinerators. Common recyclable materials include paper, cardboard, glass, metals such as aluminum and steel, certain plastics, and organic waste. The primary goals of recycling are to reduce the amount of waste sent to landfills, conserve finite natural resources, and decrease the energy use and pollution associated with producing materials from raw sources. Although recycling is often presented as a simple environmental solution, it is a complex system with significant scientific, economic, and logistical limitations.
Recycling is rooted in materials science and industrial engineering. Different materials behave differently when broken down and reused, which directly affects how recyclable they are. For example, metals such as aluminum can be recycled repeatedly without losing quality, while plastics degrade each time they are recycled. Recycling supports the idea of a circular economy, where materials remain in use for as long as possible, reducing the need for constant extraction of new raw resources. However, a circular economy only functions effectively when recycling systems are well-funded, properly managed, and supported by strong demand for recycled materials.
While humans have reused materials for thousands of years, modern recycling systems in the United States began to take shape in the 1970s. This shift was driven by widespread environmental advocacy, increased public concern over pollution, and landmark environmental legislation. Events such as the first Earth Day in 1970 helped bring waste management and resource conservation into the public spotlight. Municipal recycling programs expanded rapidly in the decades that followed, although their effectiveness has varied widely by region.
How Recycling Works
Recycling systems generally follow three major stages: collection and sorting, processing and manufacturing, and selling and reuse.
Collection and Sorting: Recyclable materials are collected from homes, schools, and businesses and transported to material recovery facilities. At these facilities, materials are separated using a combination of human labor and automated machinery such as magnets, air classifiers, and optical scanners. Plastics must be sorted by resin type because different plastics melt at different temperatures and cannot be processed together.
Processing and Manufacturing: After sorting, materials are cleaned and broken down into raw forms. Paper is pulped, glass is crushed, metals are melted, and plastics are shredded and remelted. These raw materials are then used to manufacture new products, such as recycled paper, aluminum cans, or plastic containers.
Selling and Reuse: Recycled materials must be sold to manufacturers in order to be reused. If there is insufficient demand, materials may still end up discarded. Additionally, many materials have a limited recycling lifespan and eventually become unusable due to degradation.
Beyond standard curbside recycling, several specialized recycling systems exist. Organics recycling involves composting food scraps and yard waste to produce nutrient-rich soil. E-waste recycling focuses on recovering valuable metals from electronics while safely handling hazardous components. Textile recycling includes clothing donation, fiber recovery, and the respinning of old materials into new yarns. These systems often rely on drop-off centers, take-back programs, or local initiatives rather than curbside pickup. These categories of recycling are also quite important, and possibly more promising than plastic recycling, and we may expand on them in a future lesson.
Plastic Recycling: A Closer Look
Plastic recycling is particularly challenging due to the wide variety of plastic types and additives. Mechanical recycling is the most common method and involves physically breaking down plastics into pellets that can be remolded. While this process creates a closed material loop, plastics degrade with each cycle, limiting how many times they can be recycled. In the United States, only about 20.9% of PET plastics and 10.3% of HDPE plastics are successfully recycled.
Chemical recycling, sometimes promoted as a solution to plastic waste, breaks plastics down into chemical components. In practice, many chemical recycling processes convert plastics into fuel rather than new plastic, raising concerns about energy use and pollution. Currently, chemical recycling is not widely proven to be environmentally beneficial, as on top of being quite inefficient and unproductive, it can produce harmful byproducts.
The Pros and Cons
When effective, recycling can reduce landfill waste, conserve natural resources, and save energy. For example, recycling aluminum uses significantly less energy than producing aluminum from raw ore. Recycling also supports jobs in collection, processing, and manufacturing, contributing to local and regional economies.
Despite its benefits, recycling faces significant challenges. Contamination from non-recyclable items can render entire batches unusable. Recycling infrastructure is expensive to build and maintain, and many materials are not economically viable to recycle. Plastic recycling in particular has low success rates and is often overstated in public messaging.
The 3 Rs of Sustainability
I’m sure the 3 Rs have been hammered into your head from a very young age: reduce, reuse, recycle. These values have been harped on since we were first graders, but for some reason, the only one that seems to get pushed is recycle, despite it being last in the pneumonic. And that is for good reason; it’s meant to show that it’s the least priority of the three, since it is far less effective than reducing consumption and reusing what you already have. However, since it’s the easiest and requires the least effort on the consumers’ end and the least dip in profits on the producers’ end, it’s pushed the most.
Recently, there have been efforts to redefine the Rs of Sustainability. A common version is the 5 Rs: refuse, reduce, reuse, recycle, and rot. I find this version to be a big improvement on the previous three, but I think we can expand these even a bit further, combining many sustainability experts’ ideas into…
The (New and Improved!) 7 Rs of Sustainability
The 7 Rs: Rethink, Refuse, Reduce, Reuse, Repair, Recycle, and Rot, can be understood as an individual line of thinking that guides more sustainable choices. Rather than treating all actions as equally effective, this framework emphasizes that the timing of an action matters. Actions taken earlier in a product’s lifecycle prevent environmental harm, while actions taken later attempt to manage harm after it has already occurred.
This order reflects a shift away from viewing sustainability as simply managing waste and toward preventing waste from existing in the first place. When taught this way, the Rs become a pathway rather than a checklist.
I’m aware that 7 is relatively larger than 3 and makes this a bit harder to push as a pneumonic. But, I’d argue that that actually makes kids and teens and adults and everyone else who learns these Rs actually think about them and the intentional order they are in instead of just letting it become stuck in their heads.
So, what do each of these Rs represent?
Rethink (Most Important!): Rethinking means pausing before consumption to question necessity, production methods, and end-of-life impacts. Because it occurs before any material enters the system, it has the greatest potential to prevent environmental harm.
Refuse: Refusing unnecessary items, especially single-use products and excess packaging, stops waste at the source and reduces demand for harmful products.
Reduce: Reducing focuses on consuming less overall, which lowers resource extraction, energy use, and pollution across the entire supply chain.
Reuse: Reusing items in their original form extends product lifespans and avoids the energy costs associated with manufacturing and recycling.
Repair: Repairing items challenges disposability by preventing premature disposal and reducing the need for replacement goods. I find this R especially important, as it can be better for the environment and more financially responsible to repair your goods at home (only when safe to do so, of course) than choosing instead to replace the original item entirely.
Recycle: Recycling breaks materials down into raw forms, conserving some resources but requiring significant energy and infrastructure.
Rot: Rot refers to composting organic waste so nutrients can return to the soil, reducing methane emissions from landfills.
Understanding the relative importance of the Rs helps clarify why recycling alone cannot solve environmental challenges. The most effective strategies focus on prevention, while the least effective strategies manage waste after harm has already occurred.
By applying the Rs in this order, individuals can make more informed choices while recognizing that broader systems and policies also play a critical role in achieving sustainability.
Key Takeaway
Recycling is an important tool within broader sustainability efforts, but it is not a standalone solution. Understanding both its benefits and limitations allows individuals and communities to make more informed environmental choices.