News :Pollution Caused by Paper Mills

By Navjot Sidhu

Paper pollution refers to environmental pollution caused by the production, use, and recycling of paper. Paper pollution causes severe adverse effects on the quality of air, water, and land. Discarded paper is a major component of many landfill sites. Paper recycling is also a source of pollution due to the sludge produced during drinking.

The amount of paper and paper products used is so enormous that the environmental impact of the pollution caused by it is also very significant. Therefore, great efforts are required 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 the United States, and studies show that it releases well over 100 million kg of toxic pollution each year.

The main components of pulp mill related pollution are chlorine and chlorine-based materials, sulfur, hydrogen sulfide and sulfur dioxide. 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 that are persistent organic pollutants that are one of the most toxic human-released pollutants.

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. The presence of these organic substances results in high biological oxygen demand (BOD) and dissolved organic carbon (DOC).

Sulfur-based compounds are used in kraft process as well as sulfite process for making wood pulp. The release of sulfur dioxide is of particular concern because it is water soluble and is a major cause of acid rain.

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

Nitrogen dioxide(NO) sulfur dioxide (SO) and carbon dioxide (CO) are emitted during paper manufacturing. All of them cause acid rain and CO is a major greenhouse gas that causes climate change. These toxic gases contribute to air pollution.

Wastewater discharged from a pulp and paper mills contain solids, nutrients and dissolved organic matter which when present in high levels pollute water. Nutrients such as nitrogen and phosphorus can cause or aggravate eutrophication of freshwater bodies such as lakes and rivers. Organic matter dissolved in fresh water changes ecological characteristics and may lead to the death of all higher living organisms. Wastewater may also be polluted with organochlorine compounds. Some of these are naturally occurring in the wood, but chlorine bleaching of the pulp produces far larger amounts of toxins to be released.

Delignification of chemical pulps releases considerable amounts of organic material into the environment, particularly into waterbodies. Deinking recycled paper pulp produces a waste slurry which may go to landfill.

The United States Environmental Protection Agency‎ (EPA) has found that recycling paper causes 35% less water pollution and 74% less air pollution than making virgin paper. Pulp mills can be sources of both air and water pollution, especially if they produce bleached pulp. Recycling paper decreases the demand for virgin pulp thereby decreasing the overall amount of air and water pollution associated with paper manufacture. The EPA aims at protecting human health and the environment by reducing toxic pollutant releases to the air and water. To encourage even more pollution controls it establishes a Voluntary Advanced Technology Incentives Program to encourage mills to go beyond baseline water limits. It also prescribes national emission standards for hazardous air pollutants for the production of pulp and paper.