An Introduction to Recycling and Reuse
The world was introduced to plastics in 1907, when Belgian chemist Leo Baekeland created the first synthetic plastic with two ingredients (formaldehyde and phenol).
Its popularity has been phenomenal—by 2021, some 391 million metric tons of plastics were produced worldwide, according to Statista 2023.
Unfortunately, the constant demands for plastics—which were created to be durable—have led to a world that is literally awash with plastic pollution, on both land and sea.
The first plastics recycling plant opened in 1972 in Pennsylvania, US, and, today, UK-based ENF Recycling keeps a global directory of 26,300 plastics recycling plants.
But, as the UN Environment Programme describes it, with 7 billion metric tons of plastic waste created every year and less than 10% of it recycled, “Our planet is choking on plastic.”
The sheer variety of plastics remains a major barrier to effective recycling. Plastics require specific recycling methods to deconstruct their molecular structures, and although some public education has been done about plastics recycling, there are many questions about how to sort the types and what can be done to improve the recycling success rate.
The realities of plastic recycling and what can be done to reduce plastic pollution are examined below.
The Various Types of Plastic
Most plastic packaging is labeled with a number from 1 to 7, identifying what the type of plastic is. Each type has unique properties with varying degrees of recyclability, as given below:
1 - Polyethylene terephthalate (PET or PETE) (e.g. water bottles, plastic trays)
PET is a thermoplastic polymer resin related to polyester and thus is often used for clothing fiber. It is also used for single-use bottled drinks because it is lightweight, easy to recycle, transparent, and has a reduced risk of leaching harmful substances into the environment as the plastic breaks down.
More than 82 million tons of PET were produced globally in 2021, and, because of this, PET is one of the largest sources of plastic waste. However, it is also the most commonly recycled type of plastic. Fifty-two percent of PET is recycled in Europe compared with just thirty-one percent in the US.
Most recycled PET (from bottles) in Europe does not become material for more PET bottles, according to a report produced in 2022 by Zero Waste Europe. Instead, it is turned into plastic trays, fibers, film, or strapping. Only thirty-one percent of recycled PET plastic becomes more bottle material, with sixty-nine percent being allocated to the manufacture of other PET products.
2 - High-density polyethylene (HDPE) (e.g. milk cartoons, shampoo bottles)
HDPE is a thermoplastic polymer obtained from ethylene (or sometimes called “polythene” when used for HDPE pipes). This material has a high strength-to-density ratio and is often used for the production of plastic bottles, shopping bags, corrosion-resistant pipes, geomembranes, and plastic planks as an alternative to wood. It has a high melting point and so is resistant to heat until high temperatures are reached. However, when the melting point (about 130 °C or 266 °F) has been reached, it is very malleable and can be quickly and efficiently molded for a variety of purposes.
It is easily recycled and is often accepted by recycling centers across the world, but the necessity of sorting it from other types of plastic means that only about ten to fifteen percent of it is recycled in Europe currently. This reuse rate needs to increase because HDPE is not biodegradable, and, worse still, constituent pollutants can leach out into the environment when it is landfilled.
Because HDPE can hold large volumes of goods without breaking, it is commonly used for retail and grocery shopping bags. While some US communities are seeking to ban these “plastic bags” or penalize users (charging them a nickel a bag, as in Baltimore, Maryland), there are also many retailers that offer collection points where the bags can be deposited and recycled.
3 - Polyvinyl chloride (PVC) (e.g. piping)
Polyvinyl chloride (PVC) is another widely produced synthetic polymer, available in both rigid and flexible forms. The former is suitable for constructing pipes, doors, and windows and also for plastic bottles, packaging, and credit and debit cards. Meanwhile, the latter form, with the addition of plasticizers, becomes softer and more flexible and can be used in plumbing, electrical cable insulation, flooring, signage, inflatables, and rubber substitutes. When fibers, like cotton or linen, are blended with PVC, it can be used for producing waterproof tarpaulins, canopies, and vehicle and furniture covers.
There is a common misconception that PVC cannot be recycled, but this is erroneous as there are a number of ways in which the material can be recycled. These include reuse, regrinding, melting, and repeated extrusion. However, it must be recycled separately from other plastic waste because of its high chlorine content and the high levels of hazardous additives it contains.
4 - Low-density polyethylene (LDPE) (e.g. food bags)
LDPE is made from ethylene and was first produced in 1933 by Imperial Chemical Industries (ICI). It is often used to produce transparent plastic film, such as food plastic wrap; bubble wrap; and plastic bottles. The more rigid forms of LDPE are often collected by curbside recycling operatives. Its low-density forms can also be recycled, but not as easily since it can be contaminated by the substances it was used to wrap.
5 - Polypropylene (PP) (e.g. margarine tubs, ready-meal trays)
PP is similar to polyethylene, but it is slightly harder and more heat resistant with a high chemical resistance. It can be recycled to produce a wide variety of products, but polypropylene bags must be collected, sorted, shredded, separated based on color, and then it needs to be compounded before it can be recycled effectively. Not all local recycling centers can handle PP, so there are particular companies that do this.
6 - Polystyrene (PS) (e.g. plastic cutlery)
PS (known as Styrofoam) is made from the aromatic hydrocarbon styrene and can be either solid or foamed. Its solid form is usually clear, hard, and brittle. It is not an effective barrier to oxygen or water vapor and has a low melting point, despite being one of the most widely used plastics. It is commonly used for protective packaging but is not biodegradable and, especially in its foam form, presents a serious source of litter pollution. Furthermore, while expanded polystyrene (EPS) can be recycled, classic polystyrene cannot, due to its origins as a product of hydrocarbon styrene.
7 - Others—such as polycarbonates (PC)
PCs are usually viewed as the plastics that are the hardest to recycle—if they can be recycled at all. However, PCs are translucent and resistant to impacts, which make them popular among manufacturers, especially as alternatives to glass. They are less likely to be used for food packaging due to evidence showing that they can release harmful bisphenol A (BPA). Some countries have even banned PCs for use in baby bottles for this reason.
There is a large group of additional plastic types, many of which either cannot be recycled or can be recycled only by specialist recycling companies. This group includes materials such as nylon, polycarbonate, melamine, and other substances.
Current Practices of Recycling, Reusing and Repurposing Plastic
Plastics recovered by curbside recycling teams are sent to either a Materials Recycling Facility (MRF), which separates plastic waste from other non-plastic materials, or a Plastic Recovery Facility (PRF), which sorts plastic waste by type. An optical sorter is used to distinguish the different types of plastic.
The plastics are then sent to a reprocessing plant, where they are washed, shredded, and subjected to further sorting. The third stage in the process is melting them down into plastic pellets, which are then sold for use in manufacturing other plastic products.
According to a 2017 study, only nine percent of plastics produced from 1950 to 2015 were recycled due to the complexity of the processes involved. Furthermore, a recent report by the Organisation for Economic Co-operation and Development (OECD) predicts that global plastic use will nearly triple (to 1,230 Mt) by 2060, meaning that global plastic pollution will more than double (to 1,014 Mt) from 2019 levels.
Another update, published by Greenpeace in 2022, lists five main reasons for the low rate of plastic recycling:
Plastic waste is difficult to collect.
Mixed plastic is difficult to sort.
Plastic recycling poses environmental risks.
Recycled plastics have toxicity risks.
Plastic recycling has poor economics.
Reusing Plastics at Home or Out and About
At home or out and about, there are a number of ways in which plastic can either be avoided or reused. Many people, for example, are now carrying their own reusable straws or drink containers around with them, which can be used in cafes and restaurants instead of plastic items. Likewise, sturdy canvas or plastic bags that have been kept for reuse can be used for shopping instead of accepting new plastic bags from a retailer.
When actually buying products, consumers can be selective, choosing only those goods that are packaged in truly recyclable containers, such as glass, paper, or cardboard.
Many plastic containers can be reused in the garden, for example by making hanging planters out of them. Simply fill them with soil, insert a plant or seeds and hang from a suitable location using garden twine.
A Clever Approach to Recycling
Given the low rate of recycling currently, the best thing for reducing plastic waste is to think foremost about personal consumption patterns and approach.
Perhaps the first stage in this process would be to find out from local authorities exactly what materials they recycle.
A second step would be to avoid, as far as possible, buying products using plastic packaging.
The final step would be to reuse, as far as possible, the plastics at home in various ingenious ways.
*Robin Whitlock is an England-based freelance journalist specializing in environmental issues, climate change, and renewable energy, with a variety of other professional interests, including green transportation.