Paper Recycling

Did you know?

• In 1998/99 Australians used almost 3.5 million tonnes of paper, of which almost 1.8 million tonnes were collected for recycling
• In 2005-06 more than 54,500 tonnes of paper were collected for recycling in Canberra
• Australia's newsprint recovery rate of 75% leads the world

History

Paper is a material, which has been used by man for thousands of years. The earliest known paper, made from papyrus plants, was made by the Egyptians in 2,200 BC. The Chinese invented a different method of papermaking more than 2,000 years ago. Chinese paper-makers made paper from rags, hemp and the bark of mulberry trees. The idea spread first to the Middle East and eventually was introduced to Europe in the 12th Century. For many centuries, European paper was made by hand from rags and straw, but as the world demand for paper grew, ground wood chips became the main source of fibre. With the introduction of mechanised paper making machines in the 18th century, paper became a cheap and readily available material.

Manufacture

The main raw material for paper today is wood pulp derived from wood chips, either from short fibred hardwoods (eg eucalypts) or long-fibred softwoods (eg pines). Some paper is made using cotton fibres. All paper and cardboard is made in much the same way.

The wood chips are first treated to release the fibres in one of three ways: mechanical, chemical or a combination of mechanical and chemical processes. These processes produce an intermediate stage called pulp. To make paper, the pulp is mixed with water to make a slurry which is passed over a continuous, rapidly moving mesh. The water in the pulp is drawn through the mesh, leaving the fibres behind on the mesh. The damp paper is then passed over a series of rollers to flatten and dry it. In some cases, substances like starch are added to the surface of the paper to give it certain required characteristics. At the end of the process, the paper is rolled onto huge spools. The paper or cardboard formed in this way is then sent to other factories where it is cut to the required size and shape. Corrugated cardboard is made by laminating a fluted sheet of cardboard between two flat sheets of cardboard.

Recycling

Unlike the process of making paper from virgin materials, making paper from waste paper rarely requires chemical pre-treatment. The waste paper is mixed with water in a machine that looks like a giant blender and converted into a thin slurry of individual fibres. This slurry is treated to remove contaminants such as plastic, string and paper clips using sophisticated screening techniques. It is then made into paper in the same way as making paper from virgin material.

In 1995/95, Australians used almost 3.3 million tonnes of paper, with almost 1.4 million tonnes of waste paper collected for recycling. The major proportion of the waste paper came from packaging materials, with smaller amounts of newspapers, magazines and writing paper (Source: Amcor). In 1995/96, 87% of waste paper recycled in Australia was used to make packaging and industrial paper, with most of the remainder being used to make printing and writing paper, tissues and newsprint. Small amounts were used for commercial grass seeding, insulation, animal bedding, kitty litter and moulded paper products, such as egg cartons, food trays and seedling pots.

According to the Industry Commission, there are some limitations to paper recycling. "Paper can be recycled into a wide variety of paper and other cellulose products. Contamination problems limit its reuse in food packaging such as milk cartons, and the degradation of fibres (during recycling) mean that used paper is generally 'down graded' as it is recycled. Thus, old newspapers cannot be used to produce high quality printing and writing papers, but they can be used in applications requiring mechanical pulp, such as newsprint and tissue."

The degradation of fibres during recycling also limits the number of times that a particular paper fibre can be recycled. Adding some virgin fibre or good quality waste fibres to the recycled pulp can improve the quality of the recycled product. Although old newspapers have been used for many years to make packaging materials, until recently they were not used to make recycled newsprint. This was because of difficulties with the de-inking process. According to the Publishers National Environment Bureau (PNEB), these difficulties have been resolved and a new de-inking and recycling plant in Albury, New South Wales is now producing newsprint (the paper used to make newspapers) using a mixture of old newspapers and magazines, and virgin pulp.

All newsprint manufactured in Australia now contains up to 40% recycled fibre (Source: PNEB). In the de-inking process at this plant, soaps are used to remove the inks. According to the PNEB, the inky residue is used as a soil conditioner. In 1996, over 330,000 tonnes of old Australian newspapers were recycled, both in Australia and overseas, into a variety of products including new newsprint, cardboard and packaging, housing insulation and animal bedding (PNEB).

Sources

Industry Commission, 1990, Interim Report on Paper Recycling.

Beverage Industry Environment Council, 1996, Recycling Audit and Garbage Bin Analysis, June - September.

McGregor, P., 1988, Paper, Learning Activity Topic, Centre for Economic Education.

Publishers National Environment Bureau (PNEB), 1994, Old Papers to Newspaper - a Recycling Success Story.

Pulp and Paper Manufacturers Federation, 1994. Pers. comm.

Pulp & Paper Perspective, 1996, Volume 17, September.

Recycling and Resource Recovery Council, 1994, Recycling and Resource Recovery in Victoria, Annual Report.