Paper pollution

The production, use and recycling of paper has a number of adverse effects on the environment which are known collectively as paper pollution. Pulp mills contribute to air, water and land pollution. Discarded paper is a major component of many landfill sites, accounting for about 35% by weight of municipal solid waste (before recycling).. Even paper recycling can be a source of pollution due to the sludge produced during deinking.

"People need paper products and we need sustainable, environmentally safe production." The amount of paper and paper products is enormous, so the environmental impact is also very significant. It has been estimated that by 2020 paper mills will produce almost 500,000,000 tons of paper and paperboard per year , so great efforts are needed to ensure that the environment is protected during the production, use and recycling/disposal of this enormous volume of material.

Pulp and paper is the third largest industrial polluter to air, water, and land in both Canada and the United States, and releases well over 100 million kg of toxic pollution each year.

Worldwide, the pulp and paper industry is the fifth largest consumer of energy, accounting for four percent of all the world's energy use. The pulp and paper industry uses more water to produce a ton of product than any other industry.

Sources of pulp mill related pollution

Chlorine and chlorine-based materials

Main article: Bleaching of wood pulp §  Environmental considerations

Chlorine and compounds of chlorine are used in the bleaching of wood pulp, especially chemical pulps produced by the kraft process or sulfite process. Plants using elemental chlorine produced significant quantities of dioxins. Dioxins are persistent organic pollutants that are generally recognized among the most toxic human-released pollutants in existence. Elemental chlorine has largely been replaced by chlorine dioxide and dioxin production very significantly reduced. The promise of complete removal of chlorine chemistry from bleaching processes to give a TCF (totally chlorine-free) process, which peaked in the mid-1990s, did not become reality. The economic disadvantages of TCF, the lack of stricter government regulation and consumer demand meant as of 2005 only 5-6% of kraft pulp is bleached without chlorine chemicals. A study based on U.S. Environmental Protection Agency‎ (EPA) data concluded that "Studies of effluents from mills that use oxygen delignification and extended delignification to produce ECF (elemental chlorine free) and TCF pulps suggest that the environmental effects of these processes are low and similar."

The used process water from a pulp mill contains a lot of organic material such as lignin and other organic material from the trees (including chlorinated organic material) resulting in high biological oxygen demand (BOD) and dissolved organic carbon (DOC). It also contains alcohols, and chelating agents and inorganic materials like chlorates and transition metal compounds. Recycling the effluent (see black liquor) and burning it, using bioremediation ponds and employing less damaging agents in the pulping and bleaching processes can help reduce water pollution.

Sulfur, hydrogen sulfide, and sulfur dioxide

Main article: Kraft process

Main article: Sulfite process

Sulfur-based compounds are used in both the kraft process and the sulfite process for making wood pulp. Sulfur is generally recovered, with the exception of ammonia-based sulfite processes, but some is released as sulfur dioxide during combustion of black liquor, a byproduct of the kraft process, or "red liquor" from the sulfite process. Sulfur dioxide is of particular concern because it is water soluble and is a major cause of acid rain. In 2006 the pulp and paper industry in Canada released about 60,000 tonnes of sulfur oxides (SOx) into the atmosphere, accounting for just over 4% of the total SOx emission from all Canadian industries.

A modern kraft pulp mill is more than self-sufficient in its electrical generation and normally will provide a net flow of energy to the local electrical grid. Additionally, bark and wood residues are often burned in a separate power boiler to generate steam. If the harvested trees are replanted a kraft mill can be carbon-neutral, but reforestation has been criticized for reducing biodiversity.

Air emissions of hydrogen sulfide, methyl mercaptan, dimethyl sulfide, dimethyl disulfide, and other volatile sulfur compounds are the cause of the odor characteristic of pulp mills utilizing the kraft process. Other chemicals that are released into the air and water from most paper mills include the following:

• carbon monoxide
• ammonia
• nitrogen oxide
• mercury
• nitrates
• methanol
• benzene
• volatile organic compounds, chloroform.

Mechanical pulp mills

Main article: Pulp mill § The mill

Main article: Bleaching of wood pulp § Bleaching mechanical pulps

Wood pulp produced primarily by grinding wood is known as "mechanical pulp" and is used mainly for newsprint. These mechanical processes use fewer chemicals than either kraft or sulfite mills. The primary source of pollution from these mills is organic material such as resin acids released from the wood when it is processed. Mechanical wood pulp is "brightened" as opposed to bleached using less toxic chemicals than are needed for chemical pulps.

Paper mill pollution

It is a common misconception that all mills are "pulp and paper" mills. This is true only for "integrated mills" that consist of both a pulp mill and a paper mill on the same site. While pulp mills are often conspicuous by their size and odor, paper mills are often indistinguishable from factories seen in most communities. The major effluent from a paper mill is a suspension of paper fibers in water and it is in the mill's best interest to keep such fiber loss to a minimum since any lost fiber translates to lower paper production.

See also

• Environmental issues with paper
• Printing and the environment

External links

• Using ATP to Measure Living Biomass in Wastewater Bioeactors
• Reach for Unbleached foundation
• Environment Canada's National Pollutant Release Inventory Fact Sheet
• Whats In Your Paper - Home Page