Paper is one of the biggest challenges to modern waste disposal. Paper makes up around 35 percent of domestic waste by weight and can cause significant problems in landfill. Huge quantities are used for disposable products such as newspapers and packaging and while the basic raw material – softwood – is renewable, significant amounts of energy and chemicals are used in the production process. Most paper is produced using woods such as birch or aspen, but other fast growing trees such as poplar, ash and empress tree varieties are commonly used.
Many kinds of recycling are aimed at recovering scarce raw materials; electrical scrap, for example, contains valuable metals. Recycling plastics reduces the amount of oil used for producing new materials. That doesn’t really apply to paper because most new pulp is made from sustainable softwoods grown for the purpose. However converting raw wood to paper is an energy-intensive process, and while modern mills generate most of their power by burning scrap wood and bark this can create significant carbon emissions. Waste paper is usually printed, and as it decomposes in landfills the ink leaches out into the ground. This often causes heavy metal contamination of soil and even the water table.
Paper recycling saves considerable amounts of energy; reprocessing one ton of waste back into pulp saves the equivalent of about two barrels of oil compared to producing a ton from timber. It also saves 17,000 gallons of water, and water that’s been used for paper processing needs extensive treatment before it can be put back into the environment. Finally, while recycling does require bleaching and other chemical processes the quantities used are much lower than with fresh pulp.
The USA was a pioneer of paper recycling, with the first mill set up in 1690, and 1993 was the first year when more was recycled than sent to landfill. More than 50 percent of all US paper waste is now reprocessed. Early recycled paper was usually of low quality and was mostly used for packing materials, toilet paper or cheap writing pads. Modern plants can produce much higher quality products in various grades and suitable for most purposes. Chlorine-free bleaches allow good quality paper to be produced with a much reduced environmental impact.
There is still a lot of room for improvement in paper recycling. The most obvious point is reducing the amount still going to landfill, which is currently around 46 percent of the total. Most of this comes from municipal trash; domestic waste recycling is increasingly efficient in most states. Unsold publications are also routinely pulped and recycled. Other issues include the often toxic chemical sludge produced when de-inking waste paper, which can add up to over 20 percent of the total weight. Newer technologies like plasma arc processing may be able to reduce the volume of this while recovering reusable metals from it.
Paper recycling isn’t an infinitely sustainable process; the fibers in the pulp that give the paper its strength gradually break down and shorten each time it’s processed, with the limit currently being around seven cycles before it’s no longer possible to make usable quality paper. Improved technology may extend this, or alternative uses could be found for exhausted pulp. In any case it’s essential to increase the recycling rate as much as possible to get the most from the energy used in initial production.