What is wood pulp?

Wood is made up of two basic substances: cellulose (fibres) and lignin (which is essentially the glue that holds the fibres together). When the fibres are separated, the result is wood pulp.

Mechanical pulping and chemical pulping are two common processes for separating the fibres. Mechanical pulping grinds the wood into individual fibres, while chemical pulping dissolves the lignin. The most common chemical pulp is kraft pulp, made through an alkaline cooking process that breaks the lignin down with the help of sodium sulphate. Bleached kraft pulp is known for its strength, absorbency and brightness, and is used to produce a wide range of products.

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How is paper made?
The basic process for making paper is simple. Pulp fibres are combined with water and other ingredients, forming a mixture that is similar in consistency to orange juice. The mixture is strained through a fine screen, which serves as a bed for the mat of wet fibres. The mat is dried with the help of heat, gravity, pressure and vacuum technologies, and the result is paper.

Modern papermaking machines can produce more than 700 tonnes a day at speeds of over 1,400 metres a minute. Equipment is customized to make many paper products, with different levels of quality. The machines and processes vary, but they do have things in common. They are all complex and they require the dedication of highly skilled workers.

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What materials can be used to make paper?

Paper can be made from a wide range of fibres. The Egyptians made the earliest known paper from reeds, called papyrus. The Chinese made their first paper from a combination of wet silk rags, bark, hemp and old fish nets. Much later, cotton and linen rags became the favoured raw materials, giving way to wood fibres in the mid-19th century.

Cotton fibres are still used to make money, and companies continue to test non-wood fibres like wheat straw, flax and hemp. Small amounts are sold commercially, but wood fibres are currently the best way to make high quality paper at a relatively low cost.

Trees are an abundant, renewable resource, and can continue to supply the demand for paper products—as long as we manage the forest sustainably. Sustainability includes things like regenerating all harvested areas, maintaining biodiversity and protecting the quality of soil and water. It also means making efficient use of what we have. In most cases, whole logs are used for making lumber and plywood. The wood that's left over is chipped and made into pulp, as are smaller logs and branches. Bark is used for fuel, while byproducts of the pulping process are used to generate products like turpentine.

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Does the industry support recycling?

Yes, for two important reasons. With the growing problem of solid waste disposal, recycling is one way to reduce pressure on our landfill sites. It also extends the life of wood and paper products, helping to make efficient use of our resources.

The world population is rising, as are levels of income and literacy. Each of these trends will increase the demand for wood and paper products.

At the same time, the amount of waste recycled is also expected to grow. Between 1980 and 1998, Ontario's consumption of waste paper increased by 260%—to more than 2.1 million tonnes a year. In 1980, recyclable paper made up only 17% of the material used to manufacture paper and paperboard in Ontario. With improved collection, sorting and cleaning technologies, this figure increased to about 47% in 1998.

In terms of diverting paper waste from landfill, national data shows the amount climbing steadily from 20% in 1980 to 45% in 1997. It will continue to rise as collection programs are expanded to include more recyclable materials.

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Why can't all paper be made from recycled paper?

While paper products, in particular, enjoy tremendous recycling potential, it is important to recognize that recycling does not replace the need to harvest trees. Although wood fibres can be recycled, they do have a limited lifespan. Some are lost in the de-inking or paper-making process. The rest get weaker each time they're recycled, which means that in most cases, some new (or virgin) fibre must be added to maintain product strength.

Supply is another issue. Since Ontario companies export about 60% of the paper and paperboard they make, there is a limited local supply of waste to recycle. Waste paper must be imported to satisfy the needs of Ontario mills. In 1998, the industry imported about 47% of its waste paper requirements, or 992,000 tonne

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Is the pulp and paper industry a large consumer of energy in Ontario?

The manufacture of pulp and paper is energy intensive. Electricity is used to run machinery and large amounts of heat are needed to dry the pulp and paper.

Over the past decade, the Ontario pulp and paper sector used 140 – 145 petajoules per year, which represents about 18% of the total energy consumed by Ontario industry.

Many companies have undergone audits to find ways to reduce energy consumption. Between 1990 and 1997, while production of pulp and paper increased by 17%, total energy use increased by less than 9%. During the same period, energy use per unit of production (a measure of energy efficiency), decreased by 8%. The trend to more efficient operation and energy use continues as mills fight to stay open due to an unprecendented number of challenges, including some of the highest electricity rates in North America.

By using wood waste such as bark as an energy source, we can continue to reduce non-renewable fossil fuel consumption while minimizing our impact on the environment and reducing energy costs. Referred to as biomass, wood waste accounted for 43% of the sector's energy consumption in 1990, while fossil fuels accounted for 36%. By 1997, those figures had changed to 49% and 30% respectively. During this period, overall use of fossil fuels dropped by 11%, while the use of fossil fuels per unit of production decreased by 18%.

A number of companies also have their own hydro-electric generating facilities, and some use cogeneration, which makes efficient use of fuel by producing electricity and heat simultaneously.

And further investment in new technologies continues with alternative fuels and gassification technology being explored as potnetial future energy.

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Why does the industry continue to use chlorine?

For many paper products, bleached pulp is required to meet customer demands for cleanliness and brightness. However, the use of elemental chlorine has declined considerably, in favour of chemicals like chlorine dioxide, ozone and hydrogen peroxide, which have been found to offer environmental advantages.

In 1987, trace amounts of dioxins and furans were discovered in the waste water of bleached kraft pulp mills—which used elemental chlorine as part of the pulping process. In response, the Pulp and Paper Research Institute of Canada (Paprican) initiated a research program to determine how the dioxins and furans were formed, and to find ways to prevent them. Between 1988 and 1999, the emission of dioxins and furans from Ontario bleached kraft pulp mills dropped by 98%. Companies were able to virtually eliminate these emissions by reducing or eliminating the use of elemental chlorine.

AOX (adsorbable organic halides) is a parameter used to measure chlorinated organics in bleached kraft pulp mill effluent. During the same period, Ontario mills reduced their levels of AOX by 92%.

Pulp bleached without elemental chlorine is referred to as ECF—or elemental chlorine free. If it is bleached using neither elemental chlorine nor chlorine dioxide, it is called TCF—or totally chlorine free. Few mills make TCF pulp, since it is generally less bright, less strong and more costly than ECF pulp, while offering no measurable benefits and little consumer demand.

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What are pulp and paper mills doing to make sure their wastewater discharges are not hurting the environment?

In the last several years, advanced treatment technologies have helped to minimize the environmental impact of pulp and paper mill effluent. Monitoring techniques have continued to improve and regulations have become more stringent.

The amount of material in effluent is measured in terms of two key parameters: total suspended solids (TSS) and biochemical oxygen demand (BOD).

Between 1975 and 2000, levels of TSS and BOD were reduced by about 94% and 98% respectively, due primarily to the installation of treatment facilities at mills throughout Ontario.

The industry worked closely with the provincial government to develop new regulations for pulp and paper mill effluent, which became fully effective in 1996. In addition, recent federal regulations require mills to monitor effluent quality, plus the health of fish and other aquatic life nearby.

Many companies are also involved in the voluntary ARET program, which stands for the Accelerated Reduction and Elimination of Toxics. ARET is an important industry and government initiative designed to speed the reduction or elimination of toxic substances through voluntary action. As of 1997, the pulp and paper sector had decreased emissions of ARET substances by 13,577 tonnes or 69% from 1990 base-year levels. This includes chloroform, formaldehyde, phenol and others—depending on the mill and process used.

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Why do some mills smell?

The characteristic rotten egg odour is specific to kraft pulp mills, which use sulphur as part of their process. It occurs when pulping byproducts containing sulphur are burned to recover their energy and chemical content, or when tiny amounts of gas escape from tanks or the pulp mill effluent.

Although the smell does not pose a risk to human health, it is unpleasant. Many companies have already taken steps to reduce the odour, adding control systems and low odour boilers, and making other changes to the process. The 1989, sulphur gas concentrations reached levels considered objectionable about 1.8% of the time for a typical mill. By 1998, that was down to 0.5% of the time. This represents a decrease of approximately 70%.

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How does the industry balance economic and social needs with the need to protect the environment?

In Ontario, each pulp and paper mill must comply with provincial and federal effluent regulations, and various air quality standards. Members of the OFIA also adhere to a Statement of Environmental Policy and, as part of their individual efforts, are responsible for implementing environmental policies throughout their operations.

In addition to protecting land, water and air from pollution, we recognize that the future of the industry depends on the health of our future forests. As a condition of membership, companies that conduct forest management activities must adhere to the OFIA Code of Forest Practices, with regular reviews of their performance. Nationally, the industry has also helped to develop a certification program for sustainable forest management.

These efforts are part of a broader commitment to sustainable development, which has been defined as development that meets the needs of the present without compromising the ability of future generations to meet their own needs. Within this concept, companies can continue to make use of the forest resource—make the products people depend on, provide jobs and fuel the economy—as long as we also protect the environment.

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How many sheets of paper can be made from a single tree?

For this question we turned to the Forest Products Association of Canada, which published the following response on its website (www.fpac.ca):

This is often referred to as the "impossible question," not only because of the number of variables involved (i.e. tree size, tree type, type of paper, paper weight…), but because in general, trees are not harvested for the purpose of making paper. Nonetheless, we will attempt to provide a "ball-park" figure for this "very" frequently asked question.

First a little background information on papermaking. In Canada, 50% of our paper is made from wood chips, a by-product of the lumber industry. These chips used to end up in landfills, decomposing and emitting methane—a greenhouse gas associated with global warming. By using sawmill residues for papermaking, it is estimated that more than 60 million tonnes are being diverted from landfills each and every year. Another 25% of paper is actually made from recycled paper. Since 1989, the Canadian pulp and paper industry has invested $2 billion in recycling equipment. As a result, Canadian paper mills have become world leaders in the export of recycled content paper. There are now approximately 62 Canadian mills using recovered paper. In 1999 alone, Canadian mills used 5.2 million tonnes of recycled paper in their operations.

While paper can be recycled up to nine times, the wood fibre that gives paper its strength loses its properties with each recycling. Therefore, some new wood fibre will always be needed in papermaking. The trees that are used, however, are those rejected for lumber production because they are either diseased, of poor quality or too small for timber making.

Now, keeping this in mind, here's our hypothetical answer to this hypothetical question:

Without the benefit of recycled paper or woodchips, a small eastern Canadian black spruce tree with a 6-inch diameter at chest height could make over 12,500 sheets of 10M weight 8 ½ x 11 inch bond writing paper. Or you could make 62,500 $20 bills instead. Your choice—hypothetically speaking, of course.

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