Recycling Cardboard, Plastic, and Paper: An Overview

Baled cardboard in stacks.

Recycling is an essential process for waste management and conserving resources. Among the most commonly recycled materials are cardboard, plastic, and paper. Each of these materials undergoes a transformation from waste into reusable products. This post provides an overview of how these materials are recycled and highlights the importance of these practices in promoting sustainability.

How is cardboard recycled?

Cardboard is one of the easiest and most efficient materials to recycle. The process begins with the collection of used cardboard, which once collected, is transported to a recycling facility where it is sorted and separated from other types of paper products.

The next step involves shredding the cardboard into small pieces, which are then mixed with water to form a slurry. This slurry is thoroughly cleaned to remove any impurities such as ink, tape, or staples. After cleaning, the slurry is pulped and blended to form a consistent mixture. The pulped material is then spread onto a conveyor belt or screen where the water is drained away, leaving behind sheets of cardboard fibres. These sheets are pressed and dried to remove any remaining moisture. The final product is rolled into large reels of recycled cardboard, which can be cut and shaped for various uses. Recycling cardboard not only saves trees, it reduces landfill waste and consumes less energy compared to producing new cardboard from raw materials.

Large-scale cardboard waste is often best pressed down by compacting machines that reduce the volume and can then be sold to recycling facilities, providing a handy investment for companies that are looking to mitigate their skip pickups and reduce waste at their premises.

Baled cardboard in stacks.

How is plastic recycled?

Recycling plastic is a more complex process due to the variety in plastic types and their different chemical compositions. Recycling starts with the collection and sorting of plastic waste. Plastics are sorted based on their resin identification code, which ranges from a classification beginning at 1 and ending at 7 (PET, HDPE, PVC, LDPE, PP, PS, and other various plastics). Sorting can be done manually or through automated systems using advanced technology such as infrared sensors, which works because different plastics absorb and reflect specific wavelengths of infrared light in unique ways; by analysing these patterns, the sensors identify the type of plastic based on its spectral signature.

Once sorted, the plastics are cleaned to remove contaminants like food residue, labels, and adhesives. After cleaning, the plastics are shredded into small flakes or pellets. Depending on the type of plastic, these flakes may undergo further processing to refine their quality. For example: PET plastics often undergo a process called “re-polymerisation” where they are melted down and reformed into new products.

The recycled plastic is then used to manufacture a variety of new products, ranging from plastic bottles and containers to textiles and construction materials. Recycling plastic helps reduce the dependency on fossil fuels, lowers greenhouse gas emissions, and minimises plastic pollution in the environment.

Some commercial companies who produce large quantities of plastic invest in plastic balers to reduce their overall volume, keep their sites clean, and save on costs associated with waste transportation, as well as reducing CO2 emissions from large transport vehicles.

How is paper recycled?

Paper recycling is a well-established, decades-old practice. The process begins with the collection of waste paper, which is then sorted into different categories based on the type and quality of the paper, such as newspapers, office paper, and cardboard. The sorted paper is transported to a recycling facility where it is mixed with water and chemicals to break it down into its fibres. The mixture is then pulped, resulting in a slurry that is screened to remove any contaminants like plastic, staples, or glue, much like the process of recycling cardboard.

The clean slurry is then spread onto screens to form sheets, which are pressed and dried to produce recycled paper. These sheets can be rolled and cut into different sizes for various uses, including printing paper, packaging materials, and tissue products. Recycling paper conserves trees, saves water and energy, and reduces greenhouse gas emissions associated with paper production.