Environmental Impact of Industrial pollution - paper, dye and textiles

1.   Environmental impact of paper industry

It has been estimated that by 2020 paper mills will produce almost 500,000,000 tons of paper and paperboard per year. On an average more than one kilolitre of water is required to produce one tone of paper, releasing 100 million kg of toxic pollutants including nutrients, sodium,   dissolved organic matter every year. Nutrients such as N and P can cause or exacerbate eutrophication of fresh water bodies such as lakes and rivers. Organic matter dissolved in fresh water, measured by Biological Oxygen Demand (BOD), changes ecological characteristics, and in worse case scenarios leads to death of all higher living organisms. Waste water 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. Discharges can also discolour the water leading to reduced aesthetics. This has happened with the Tarawera River in New Zealand which subsequently became known as the "black drain". 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 Elemental chlorine has largely been replaced by chlorine dioxide and dioxin production very significantly reduced.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 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.

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.

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

Bleaching mechanical pulp is not a major cause for environmental concern since most of the organic material is retained in the pulp, and the chemicals used (hydrogen peroxide and sodium dithionite) produce benign byproducts (water and sodium sulfate (finally), respectively).

However, the bleaching of chemical pulps has the potential to cause significant environmental damage, primarily through the release of organic materials into waterways. Pulp mills are almost always located near large bodies of water because of they require substantial quantities of water for their processes.

Three main issues with the environmental impact of printing inks is the use of volatile organic compounds, heavy metals and non-renewable oils. Standards for the amount of heavy metals in ink have been set by some regulatory bodies. There is a trend toward using vegetable oils rather than petroleum oils in recent years due to a demand for better sustainability.

Deinking recycled paper pulp results in a waste slurry which may go to landfill. De-inking at Cross Pointe's Miami, Ohio mill in the United States results in sludge weighing 22% of the weight of wastepaper recycled.

Conventional bleaching using elemental chlorine produces and releases into the environment large amounts of chlorinated organic compounds, including chlorinated dioxins. Dioxins are recognized as a persistent environmental pollutant, regulated internationally by the Stockholm Convention on Persistent Organic Pollutants.

Dioxins are highly toxic, and health effects on humans include reproductive, developmental, immune and hormonal problems. They are known to be carcinogenic. Over 90% of human exposure is through food, primarily meat, dairy, fish and shellfish, as dioxins accumulate in the food chain in the fatty tissue of animals.

Nitrogen dioxide (NO₂) sulfur dioxide (SO₂) and carbon dioxide (CO₂) are all emitted during paper manufacturing. Nitrogen dioxide and sulfur dioxide are major contributors of acid rain, where as CO₂ is a greenhouse gas responsible for climate change.

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 Canada  in 2006.

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, chloroform.

Deforestation

Worldwide consumption of paper has risen by 400% in the past 40 years, with 35% of harvested trees being used for paper manufacture. Logging of old growth forests accounts for less than 10% of wood pulp, but is one of the most controversial issues. Plantation forest, from where the majority of wood for pulping is obtained, is generally a monoculture and this raises concerns over the ecological effects of the practice.

Deforestation is often seen as a problem in developing countries but also occurs in the developed world. Wood chipping to produce paper pulp is a contentious environmental issue in Australia. In the 1990s, the New Zealand government stopped the export of woodchips for native forests after campaigning by environmentalists.

In a modern kraft pulp mill, 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.

Depletion of Non-renewable resources

Clay or calcium carbonate are used as fillers for some papers. Kaolin is the most commonly used clay for coated papers.

Energy Consumption Paper making is energy intensive, drawing larges amount of electricity from public utilities, or forcing mills to build their own power plants. This is a significant contributor to the air pollution in our region, and to the hidden damages due to fuel extraction at the source (oil drilling, oil spills, coal mining, pipelines, transmission lines, etc

Environmental impact of Textile mill effluent

The textile industry uses vegetable fibres such as cotton, animal fibres such as wool and silk, and a wide range of synthetic materials such as nylon, polyester, and acrylics. The production of natural fibres is approximately equal to the amount of production of synthetic materials. An average 200 litres of water is required to produce 1 kg of textile.

Aquatic toxicity

 The sources of aquatic toxicity from textile and dye industry can include salt, surfactants, ionic metals and their metal complexes, toxic organic chemicals, biocides and toxic anions. Most textile dyes have low aquatic toxicity. On the other hand, surfactants and related compounds, such as detergents, emulsifiers and dispersants are used in almost each textile process and can be an important contributor to effluent aquatic toxicity, BOD and foaming.

Suspended solids can clog fish gills, either killing them or reducing their growth rate. Other important impact, they also reduce light penetration. This reduces the ability of algae to produce food and oxygen

Solid waste production

The primary residual wastes generated from the textile industry are non-hazardous. These include scraps of fabric and yarn, off-specification yarn and fabric and packaging waste. There are also wastes associated with the storage and production of yarns and textiles, such as chemical storage drums, cardboard reels for storing fabric and cones used to hold yarns for dyeing and knitting. Cutting room waste generates a high volume of fabric scraps, which can often be reduced by increasing fabric utilization efficiency in cutting and sewing.

Accumulation of sulphates and chlorides in the soil

The other parameter, sulphates (SO4=) are not considered toxic to plants or animals at normal concentrations. In humans, small concentrations cause a temporary laxative effect. However, doses of several thousand units cause all long-term illness effects. Sulphates are toxic at very high concentrations. Problems caused by sulphates are most frequently related to their ability to form strong acids which changes the pH. In this way, phosphates are not toxic to human beings or animals unless they are present at very high levels. Digestive problems could occur from extremely high levels of phosphate