There are three categories of waste paper that can be used as feedstocks for making recycled paper: mill broke, pre-consumer waste, and post-consumer waste. Mill broke is paper trimmings and other paper scrap from the manufacture of paper, and is recycled internally in a paper mill. Pre-consumer waste is material that was discarded before it was ready for consumer use. Post-consumer waste is material that was discarded after actually being used by a consumer. The grades of post-consumer recycled paper are OCC (old corrugated containers), WCC (waxed corrugated containers), ONP (old newspapers), OMG (old magazines), OTD (old telephone directories), and RMP (residential mixed paper).
Industrialized paper making has an effect on the environment both upstream (where raw materials are acquired and processed) and downstream (waste-disposal impacts)। Recycling paper reduces this impact.
Today, 90% of paper pulp is made of wood. Paper production accounts for about 43% of harvested wood, and represents 1.2% of the world's total economic output. Recycling of newsprint saves about 1 tonne of wood while recycling 1 tonne (1.1 ton) of printing or copier paper saves slightly more than 2 tonnes of wood. This is because kraft pulping requires twice as much wood since it removes lignin to produce higher quality fibers than mechanical pulping processes. Relating tonnes of paper recycled to the number of trees not cut is meaningless, since tree size varies tremendously and is the major factor in how much paper can be made from how many trees.Trees raised specifically for pulp production account for 16% of world pulp production, old growth forests 9% and second- and third- and more generation forests account for the balance. Most pulp mill operators practice reforestation to ensure a continuing supply of trees. The Forest Stewardship Council (FSC) certifies paper made from trees harvested according to guidelines meant to ensure good forestry practices. It has been estimated that recycling half the world’s paper would avoid the harvesting of 20 million acres (80,000 km²) of forestland.
Energy consumption is reduced by recycling, although there is some debate concerning the actual energy savings realized. The EIA claims a 40% reduction in energy when paper is recycled versus paper made with unrecycled pulp. while the Bureau of International Recycling, BIR, claims a 64% reduction. Some calculations show that recycling one ton of newspaper saves about 4,000 KWh of electricity, although this may be too high. This is enough electricity to power a 3-bedroom European house for an entire year, or enough energy to heat and air-condition the average North American home for almost six months. It must be noted that recycling paper to make pulp may actually consume more fossil fuels than making new pulp via the kraft process since these mills generate all of energy from burning waste wood (bark, roots) and byproduct lignin. Pulp mills producing new mechanical pulp use large amounts of energy, a very rough estimate of the electrical energy needed is 10,000 megajoules (MJ) per tonne of pulp (2500 kW·h per short ton), usually from hydroelectric generating plants. Recycling mills purchase most of their energy from local power companies and since recycling mills tend to be in more urban areas, it is likely that the electricity is generated by burning fossil fuels.
Landfill use
About 35% of municipal solid waste (before recycling) by weight is paper and paper products. Recycling 1 tonne of newspaper eliminates 3 cubic meters of landfill. Incineration of waste paper is usually preferable to landfilling since useful energy is generated. Organic materials, including paper, decompose in landfills, albeit sometimes slowly, releasing methane, a potent greenhouse gas. Many larger landfills now collect this methane for use as a biogas fuel. In highly urbanized areas, such as the northeastern US and most of Europe, land suitable for landfills is scarce and must be used carefully. Fortunately, it is in such areas that collection of waste paper is also most efficient.
Water and air pollution
The US EPA has found that recycling causes 35% less water pollution and 74% less air pollution. Pulp mills can be sources of both air and water pollution, especially if they are producing bleached pulp. Modern mills produce considerably less pollution than those of a few decades ago. Recycling paper decreases the demand for virgin pulp and thus reduces the overall amount of air and water pollution associated with paper manufacture. Recycled pulp can be bleached with the same chemicals used to bleach virgin pulp, but hydrogen peroxide and sodium hydrosulfite are the most common bleaching agents. Recycled pulp, or paper made from it, is known as PCF (process chlorine free) if no chlorine-containing compounds were used in the recycling process. However it should be noted that recycling mills may have polluting by-products, such as sludge. De-inking at Cross Pointe's Miami, Ohio mill results in sludge weighing 22% of the weight of wastepaper recycled.
