Plastic Recycling

Plastic recycling is the process of recovering waste or scrap plastic and reprocessing these materials into other functional and practical products. Because almost all plastic is non-biodegradable, it must be recycled as part of the global efforts to reduce plastic and other solid waste in the environment.

Why should we recycle plastic?

Plastics should be recycled because of several reasons:

Plastic recycling helps conserve resources and diverts plastics from landfills or unintended destinations such as oceans (Approximately 8 million tons of plastic waste enters the world's oceans each year).
Recycling plastic requires less energy than making plastic from raw materials.
Plastic recycling helps to reduce fossil fuel consumption since virgin plastic is produced directly from the petrochemical feedstock, such as natural gas or crude oil.
Recycling plastic is less expensive and less time-consuming than manufacturing new plastic using virgin material.

How much plastic is recycled?

The amount of plastic that is recycled varies depending on the location and the specific types of plastic being recycled. In general, however, global recycling rates for plastic are low. Only 9% of all plastic produces is recycled globally. This means that 91% of plastic produced ends up in landfills or the environment.

On a daily basis, the amount of plastic recycled may depend on the recycling infrastructure and programs available in a specific area, as well as the amount of plastic waste generated. For example, a city with a well-established recycling program and high participation rates may see more plastic recycled on a daily basis than a city without such a program.

Is plastic recyclable?

No, not all plastic is recyclable. Plastic is made up of a wide variety of polymers, each with their own properties and characteristics. Some types of plastic are more easily recyclable than others.

What are plastics made of?

Plastics are made from a wide variety of materials, but the most common type of plastic is made from a polymer called polyethylene. Polyethylene is a long chain of repeating units of a chemical called ethylene.

Polyethylene is the most common plastic and it is used in a wide range of products such as bottles, containers, bags, and packaging materials. There are different types of polyethylene, including low-density polyethylene (LDPE) and high-density polyethylene (HDPE).

Some plastics are also made from a combination of different materials, such as bioplastics which are made from renewable resources such as plant materials.

What plastic is recyclable?

Some types of plastic are highly recyclable, while others aren't. The key to which plastics are recyclable is to examine the plastic for that little triangle made of arrows and then look up the number inside it. Plastic numbers 1, 2, 4 & 5 can be recycled.

#1 PETE or PET (Polyethylene Terephthalate) -Polyethylene Terephthalate is a common form of plastic used to form soft drink bottles, peanut butter jars, salad dressing, cooking oil, many cleaning products.
#2 HDPE (High-Density Polyethylene) - High-Density Polyethylene is a thicker form of plastic used for a wide variety of products due to its extreme durability. It is used primarily for packaging detergents, bleach, milk containers, hair care products, and motor oil. It is recycled into more bottles or bags.
#3 PVC (Polyvinyl Chloride) - Polyvinyl Chloride is a softer plastic used for plastic wrap, teething rings, inflatable pool toys, and pipes and tubes. Its high tolerance for sunlight and weather phenomena makes it ideal for use in garden hoses, trellises, and other outdoor products.
#4 LDPE (Low-Density Polyethylene) - Low-Density Polyethylene Is used for grocery bags, garment bags, and bread bags. LDPE is considered less toxic than other plastics and relatively safe for use. However, it is not commonly recycled, although this is changing in many communities today as more plastic recycling programs gear up to handle this material. When recycled, LDPE plastic is used for plastic lumber, landscaping boards, garbage can liners, and floor tiles.
#5 PP (Polypropylene) - Polypropylene plastic is rigid and lightweight and has excellent heat-resistance qualities. It serves as a barrier against moisture, grease, and chemicals.
#6 PS (Polystyrene) - Polystyrene by the name alone, you can guess its function. We often refer to this material as 'styrofoam' and see it most commonly used in takeaway boxes at restaurants, to-go cups for hot or cold beverages, egg cartons, and packaging peanuts. A versatile substance, it is also used as insulation and sheeting for laminate flooring. While the technology for recycling polystyrene is available, the recycling market is small.
#7 Other (BPA, Polycarbonate, and LEXAN) - This category includes a variety of plastic types, some of which are recyclable and some of which are not. You've doubtless heard of BPA and its negative connotations.

You may not have heard of PLA, a new form of compostable plastic made from corn starch. While PLA is compostable, it, along with the other #7s, is not recyclable.

Industrial plastic waste

Recyclers that process industrial plastic waste are very selective in accepting the collected plastic waste. They are actively looking for plastic waste streams suitable for recycling into regranulate or products for their buyers. In this manner, some industrial plastic waste material can be recycled profitably, with limited processing.

How plastic is recycled

Plastic recycling is broken up into different stages to be further used for making various types of products. Generally, these stages remain the same for most recycling facilities, but specific steps can be combined or omitted in some situations.

The following is a step by step process of plastic recycling:

Collection
Plastics are available in several forms: plastic bottles, plastic bags, plastic containers, packaging plastic, industrial plastics, etc. The first step in the recycling process is always collecting these plastic materials to be recycled.
Sorting
After plastics are collected and transported to a recycling facility, the next step is sorting. There are specially designed systems that help sort the plastics according to their particular resin content. This is important because different types of plastics must be processed in different ways, and some recycling facilities are only capable of recycling certain types of plastic.
Compacting
Compact sorted plastics into a square and tight bales using a baler to save storage and transportation.
Washing
After a complete separation, the plastic waste must be adequately washed to remove impurities such as labels, adhesives, or even food residue. Non-plastic waste cannot be recycled and can cause the final product to have poor structural integrity.
Resizing
Resizing consists of shredding or granulating the plastic waste into small particles. This increases the surface area of the plastic, making it easier to process, reshape, and transport if needed. For efficiency purposes, automatic feeding of the material into the shredder is a good solution.
Identification and Classification of Plastic
After shredding, proper testing of the plastic particles is conducted to determine their quality and class. The first quality tested is density. Next, their air classification is selected.
Melting
The dry flakes are melted down. They can be melted down and molded into a new shape or melted down and processed into granules.
Making of pellets
After the melting process, the plastic pieces are then compressed into tiny pellets known as nurdles. Compounding is when the small particles are smashed and melted into plastic pellets. The plastic pellets are ready for reuse or are redesigned into new plastic products in this state. Plastic pellets are delivered to plastic manufacturing facilities to make new plastic products.

The plastic may be moved to different plants that specialize in other process steps throughout this process.

The latest innovations in plastic recycling

There have been several recent innovations in plastic recycling:

Chemical recycling: This process involves breaking down plastic into its chemical building blocks, which can then be used to make new plastic products.
Pyrolysis: This method converts plastic waste into liquid fuels, such as diesel and gasoline, through a process of heating the plastic in the absence of oxygen.
Biodegradable plastics: These are plastics that can be broken down by microorganisms into simpler compounds, such as water, carbon dioxide, and biomass, over a period of time.
Plastic-to-fuel: This process converts plastic waste into a variety of fuels, including diesel and gasoline, which can be used as an alternative energy source.
Plastic-to-fibers: This process converts plastic waste into fibers that can be used to make textiles, non-woven fabrics and other materials.
Plastic-to-chemical: This process converts plastic waste into chemicals that can be used to make new products.

All of these innovations aim to increase the recycling rate, decrease the amount of plastic waste and the negative impact of plastic on the environment.

Plastic recycling technology

Some of the plastic recycling technologies currently in use include:

Mechanical Recycling: This process involves grinding, washing, and melting plastic waste to produce new plastic products. This is the most common method of plastic recycling.
Solvolysis: This process involves dissolving plastic in a solvent to separate out different types of plastics, which can then be used to make new products.
Gasification: This process converts plastic waste into a gas that can be used as a fuel.
Pyrolysis: This process converts plastic waste into liquid fuel, such as diesel and gasoline, through a process of heating the plastic in the absence of oxygen.
Depolymerization: This process breaks down plastic into its chemical building blocks, which can then be used to make new plastic products.