Waste paper is collected for recycling from people’s homes, recycling sites and businesses.
2. Sorting and grading
Before it can be recycled, collected paper must be sorted and graded; there are over 50 grades of waste paper.
The four main groups are:
3. Shredding and baling
Many businesses, offices and some homes shred documents to protect sensitive information. Companies (like SUEZ) provide a confidential shredding service to ensure that documents are collected and shredded securely. Large amounts of graded paper, including shredded paper, are compressed by a machine into a bale shape before being transported to a paper mill.
4. Pulping, screening and de-inking
At the paper mill, the graded paper is placed in a large vat and mixed with water. This process breaks down the paper into tiny strands of cellulose (organic plant material) fibres. Eventually, this turns into a mushy mixture called pulp. The pulp is then filtered and screened to remove contaminants such as glue and bits of plastic.
For certain uses, pulp must also be de-inked. There are two main methods of de-inking:
Pulp is poured onto a huge, flat wire screen. On the screen, water starts to drain from the pulp and the recycled fibres soon bond together to form a watery sheet.
The sheet, which now resembles paper, passes through a series of heavy rollers. These squeeze out more water, while some heated cylinders dry the paper, and another roller irons it.
Now the paper is wound into a giant roll, which can be as wide as 30 feet and weigh 20 tonnes. The roll is cut into smaller rolls, or sometimes sheets, before being ready for use.