Plastic is a durable and versatile material used in many sectors, particularly for packaging and everyday items. However, today, plastic pollution has become a global phenomenon, making optimal end-of-life management of plastic materials crucial to achieve environmental and social sustainability goals.
The journey towards an increasingly virtuous use of plastic materials, transforming them from waste into reusable resources for the production of new products, began in the 1990s, when the first specific studies in this field were conducted.
In recent years, thanks to the introduction of more efficient separate collection systems and the development of new technologies, the percentage of plastic waste collection and recycling has significantly increased. According to data published by Corepla in its Sustainability Reports, plastic packaging sent for recycling (most of it from urban separate collection) has seen annual increases of about 10%.
1. The Different Steps of the Plastic Recycling Process
The path to reusing plastic materials is complex and articulated, consisting of several steps ranging from production to collection, and finally to reuse for the creation of new products and objects.
The plastic recycling process begins by identifying the type of plastic to be recycled and subsequently separating plastics by size and type. Each type of plastic material has specific characteristics and composition, making correct sorting and separation of plastics an essential prerequisite to ensure the recovery of reusable material.
2. The Different Types of Plastic
The different types of plastics are recognizable by the recycling logo: a triangle with a number from 1 to 7 inside it, which distinguishes each type of plastic.
1. PET: Plastics belonging to group number 1 are made from polyethylene terephthalate or PET. This type of plastic is widely used for food and beverage packaging due to its strong ability to prevent oxidation and contamination of the product. It is easily recyclable through most separate collection programs and is the most recycled plastic in the world.
2. HDPE: High-density polyethylene is an incredibly resistant resin used for shopping bags, milk containers, recycling bins, agricultural pipes, and also playground equipment, caps, and shampoo bottles. It is one of the easiest plastic polymers to recycle.
3. PVC: Polyvinyl chloride is the third most produced synthetic plastic polymer in the world. It is mainly used in the construction sector for producing door and window profiles and pipes. However, it is still difficult to recycle.
4. LDPE: Unlike HDPE, low-density polyethylene is characterized by molecules that give this resin a thinner and more flexible design. It has the simplest structure of all plastics, making it easy and cheap to produce over time. It is used in plastic bags, various containers, dispensing bottles, and most famously for plastic wraps.
5. PP: Polypropylene is the second most produced commodity plastic and its market is expected to grow in the coming years. It is heat and impact resistant and is used in plastic containers, car parts, thermal clothing, and even disposable diapers.
6. PS: Polystyrene can be solid or foamed and is used to make beverage cups, insulation materials, packaging materials, and disposable tableware. It is considered one of the worst types of plastic for the environment as it is highly flammable and dangerous to marine animals that can ingest it.
7. Other Plastics: If a plastic cannot be identified in the six types mentioned above, it is included in group number 7. Polycarbonates are among the most well-known plastics in this group and are used for strong and durable products such as lenses for sunglasses and CDs. However, they are controversial due to the release of bisphenol A (BPA), a compound potentially dangerous for the environment.
3. What Plastics Can be Recycled?
Currently, only certain types of plastic are widely collected and recycled.
The most commonly recycled plastics are:
- 1. Polyethylene terephthalate (PET): water bottles and plastic trays.
- 2. High-density polyethylene (HDPE): milk cartons and shampoo bottles.
- 3. Polypropylene (PP): margarine tubs and ready-meal trays.
Partially recyclable plastics (in highly specialized facilities) include:
- 1. Polyvinyl chloride (PVC): piping.
- 2. Low-density polyethylene (LDPE): food bags.
- 3. Polystyrene (PS): plastic cutlery.
Plastics that are extremely difficult to recycle include chip packets, salad bags, plastic wraps, and more.
4. What Plastics Cannot be Recycled?
Even today, many plastics are not recycled. There are many technical, economic, environmental, and health reasons why a plastic cannot currently be recycled.
As we have already seen, these plastics mostly fall into category 7 and are generally sent to incinerators for disposal or to energy recovery plants, special facilities that allow plastic waste to be burned, generating electricity and alternative fuels usable in various industrial or civil sectors.
5. The Plastic Recycling Process: From Collection to Sorting and Recycling Centers
A plastic recycling process typically follows these steps:
– Sorting: Once collected through separate waste collection, plastics are sent to specialized plants, which handle the actual recycling. The second stage of the recycling process is then the sorting of plastic waste, largely performed by special machinery. The waste is sorted according to its size and composition using infrared scanners or other advanced technologies.
– Grinding: This is a crucial stage in the transformation of plastic waste into new raw material. The divided and sorted waste is sent to processing plants to be further divided according to the type of product (e.g., bags, caps, bottles, or containers). This division is very important for proper recycling.
– Washing: In this phase, the plastic is washed and cleaned to remove any residual dirt or other substances that could hinder recycling.
– Final Shredding: Once cleaned, the plastic waste is shredded to obtain plastic flakes (called ‘flakes’), which are then divided by color by special machines and then heated, cooled, and shredded again. This produces pellets, small granules of plastic material that can be used to produce new raw material.
6. Recycling Plastics with a View to a Circular Economy
The circular economy model refers to a production and consumption model that aims to extend the life cycle of products with the goal of minimizing the generation of new waste. According to the circular economy model, once the end-of-life is reached, plastic materials used in the production of packaging or everyday objects must be reintroduced into the production cycle, if possible, generating additional value.
Recycling plastics with a view to a circular economy means that technologies capable of managing all stages—from collection to shredding the pellets—are available, aiming to have the least possible final residue compared to the starting product.
In this perspective, the European Commission has recently adopted new rules to allow the use of recycled plastic in food packaging, known as Food Contact Materials (FCMs) or MOCA (materials in contact with food).
All materials and objects that under normal or foreseeable use conditions will come into contact with food must be manufactured in such a way as not to pose a danger to human health, not cause an unacceptable change in the composition of food products, not cause deterioration of their organoleptic characteristics, and not transfer substances from the material to the food.
The rules of the new regulation will help the recycling and packaging industry to create new value, reduce the use of raw materials, save energy, and increasingly limit the level of environmental and social pressure from plastic waste.
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