United Colours of Industry
Colours are inescapably embedded in everyday life. So it’s critical to know, and to regulate, the way they operate. Having said that, it’s not easy to recognise the problems associated with their use. Adulteration in food colours, or allergic reactions to elements in fabric apart, consumers are unaware of problems caused by agents and vehicles of colour.
But a look at the tailpipe in any industrial zone can cure that.Colour problem comes from two types of industries:
• Makers or users of colouring matter: dyestuffs, pigments, textiles, dyeing and tanneries are the principal ones
• Users of raw materials with colour as by-product: pulp and paper sector (where lignin imparts colour to effluents) and distilleries (where spent water is highly coloured)
The Central Pollution Control Board (cpcb) has listed the dyes and dye intermediates, pulp and paper and tanneries as heavily polluting industries. Untreated (and sometimes even treated) effluents from these industries, released into rivers, lakes or through the drainage systems, seep into the groundwater and adjoining water bodies.
Budget over quality We dye, they just buy Paints are big business Textiles: Good, Bad, Ugly Leather that weathers Pulp & paper Typical sources Back-coating operations, carpet printing
The domestic textile industry looks for manageable costs rather than consistent quality. So the bulk of its demand for dyes is met by the small-scale sector, while the organised sector looks to exports or high-end producers. The small-scale sector’s substantially lower investment in pollution control measures also makes it more economical.
Dye production in India is estimated to be around 60,000 tonnes, or about 6.6 per cent of world production. There are around 700 varieties of dyes and dye intermediates produced in India, mainly direct dyes, acid dyes, reactive dyes and pigments. Most of these dyes have not been evaluated for their impact on health and the environment. Yet, they are widely used by textiles, leather, paper, paints, plastics, printing and even in the food industry.
The largest producer of dyes in the world is Germany at 22 per cent, followed by the us at 18 per cent. Till recently, big global players (American Colour, Atlantis Chemicals, Bayer AG and Hoechst AG) controlled 60 per cent of the global dyes output. However, a gradual shift is discernible in global dye production. The number of large-scale dyestuff manufacturers in the us has reduced drastically (from 21 in 1976 to a mere ten in 2001) and the overall share of developed nations has also dropped from 65 per cent to 50 per cent. Faced with spiralling labour and environment costs, developed countries are slowly disengaging themselves from the manufacture of dyestuffs (setting up a dyeing plant in India, for instance, costs just a quarter of what it would to start up a similar plant in the West). Lack of enforcement and monitoring of regulations related to environment also make the industrialising countries in Asia a lucrative place to set up polluting industries. As China, South Korea, Taiwan and India become the new large producers, the extent of environmental and health problems are likely to shoot. Thus, the South ends up paying the real ecological costs to produce dyes for the North.
Indian dyestuffs are exported to the European Union, the us, Indonesia, Hong Kong, South Korea and Egypt, of which the us alone accounts for almost 20 per cent. World demand for dyes and organic pigments, forecast to increase over 5.2 per cent per year, reached us $14.2 billion in 2004, with volume demand reaching 1.5 million tonnes over the same period. In terms of usage patterns, China, India, South Korea and Taiwan demand dyes, while North America, Western Europe and Japan prefer to use organic pigments.
The predominant use of paints is by industry (automotive paint, high performance coating, powder coating and marine paint) and architecture (enamel, distemper, emulsion, exteriors and wood finishes). Paints have market volumes of up to 600,000 tonnes, adding up to almost Rs 6,200 crore. The unorganised sector accounts for 45 per cent of this and comprises about 2,500 units that manufacture low technology paints for local use. (see pie charts: Paint makers and Where it’s going)
Unlike textiles, the bigger share (55 per cent) here belongs to the organised sector, which is dominated by a few large players. With an annual growth of 10 to 12 per cent, domestic paint use in industry is growing at 15 per cent or Rs 1,000 crore per year and paint use in architecture/building at eight per cent or about Rs 2,200 crore.
The textile industry occupies a vital place in the Indian economy. Indian textile exports have risen from Rs 100 crore in 1967-68 to Rs 34,800 crore in 1997-98. Of this, readymade garments constitute nearly 50 per cent of India’s total textile exports and employ an estimated 35 million people directly.
Wet processing, dyeing and printing of textiles in India is mostly done in the decentralised sector. Most of these units buy their inputs from local markets and therefore lack detailed information about eco-standards and possible substitutes, technical know-how and financial resources to invest in pollution control measures.
About 80 per cent (more than 51,000 tonnes) of all dyestuff produced in India is used by textiles alone. With its needs for dyeing and printing, the textile sector is probably the worst offender when it comes to releasing coloured effluent discharge and Ludhiana, Panipat, Pali, Bichchri, Patancheru, Jetpur, Ahmedabad, Surat and Tirupur are some of the country’s most polluted zones.
As a result, textile manufacturers have faced the most protests from local people who they affect and a fair amount of litigation as well. Though in the last decade, some change has been forced, mainly under pressure from court rulings and local people’s movements, several problems still plague this sector.
India has about 3,000 tanneries with a total processing capacity of 700,000 tonnes of hides and skins per year. About 35 large firms are reported to account for 60 per cent of India’s leather exports. More than 90 per cent of the tanneries are small or medium-sized, with processing capacities of less than two to three tonnes of hides/skins per day. In India, tanneries process sheep, goatskin, cow and buffalo hides, using both vegetable and chrome tanning. The highest concentration of tanneries in India is along the banks of the Ganga river in North India and around the Palar river system in Tamil Nadu.
Most tanneries in India use old technologies and production methods. Even in large tanneries, the technology used is inefficient. This is largely responsible for the wasteful use of water and chemicals, high load of effluent pollutants and low productivity.
A study of India’s tanning industry, carried out on behalf of the Union ministry of science and technology, found that the chemical consumption in Indian tanneries is about 25 to 30 per cent higher than international norms. So a tannery that needs only 100 tonnes of colour ends up using 130 tonnes. The extra 30 tonnes goes out as waste and contaminates the soil and the water around the tannery.
However, export demands for higher standards may fuel some changes in environmental standards. For instance, Germany, a major importer of leather and leather goods from India, banned the import of leather products containing more than 5 milligramme/kilogramme (mg/kg) of pentachlophenol (pcp) in 1990.
This was followed by a German ban on the import of leather and textiles treated with a number of azo dyes in 1994. The use of benzidene and arylamines in dye formulations has also been banned in Germany since 1995.
In the large-scale domestic pulp sector, 16 mills manufacture several different kinds of coloured products; on an average, each of these account for 4.12 per cent of total volumes of pulp and paper.
Colouring matter in wastewater from pulp/paper mills is organic in nature and includes wood extractives, tannins, resins, synthetic dyes and lignin. The specific dye consumption for the large-scale pulp and paper sector is 4 kg/bone dry tonnes of coloured product. Coloured paper is obtained by dyeing the paper stock or the paper surface (size press, paper coating). Additionally, fixing agents and other additives are used to improve dye fixation and to obtain better dyeing results. Both inorganic and organic pigments (for instance, azo and phthalocyanine types) and carbon black are used for paper dyeing.
Colour impacts the environment when it is released into water. Paper mills, which experience several changes of tints or shades each day, have to get their water circuits cleaned every now and then. Discharge of coloured pulping effluents in water inhibits photosynthetic activity of aquatic biota by reducing the penetration of sunlight, besides direct toxic effects on biota. The colour compounds also collect metal ions and may import contamination by heavy metals.
India’s large-scale pulp and paper sector discharged more than 100 tonnes of dyes as unused dyes each year between 1998 and 2001.
Block the print
Pollutants associated with textile Pollutant Suspended solids Discarded print paste and clear (pigment printing) Urea Print paste (wet printing) Air emissions Drying/curing oven emissions (solvents, acetic acid) Solvents Nonaqueous oil/water thickeners, machine cleaning, screen cleaning Aquatic toxicity Surfactants, solvents Colour Discarded print paste, colour kitchen operations, implement cleaning Metals Discarded print paste, photo operations, reducing agents in discharge printing, screen making, engraving operations Water (and heat) Washing of printed cloth, desizing operation Foam
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