1 Non-azo dyes.
Ref.: Miljøstyrelsen (1994a).

Cotton garment is dyed with either reactive dyes (92%, of which 75% are fixated) or sulphur dyes (8%, of which 85% are fixated).

Annually, 4-5 mill. m² of carpets are dyed in Denmark. They are primarily made of polyamide, cotton and polyamide/cotton blends.

The dyes used are acid dyes (anthraquinone and azo dyes), metal complex dyes and vat dyes (anthraquinone). Yearly, approximately 25 tonnes of colorants are used for carpet dyeing.

Colorants for printing are first and foremost pigments and reactive dyes, but also small amounts of disperse and vat dyes are used.

The annual consumption of colorants for textile printing is approximately 65 tonnes.

Mass flow analysis

There is no domestic production of dyes for textiles, and it has not been possible to obtain data on the Danish production of pigments for textile colouring. None of the restricted azo dyes are imported for textile use, according to the importers.

Knowing the output of dyed textiles, the relative amount of colour types and their fixation rates, the consumption of colorants may be calculated. On this basis, the volume of azo colorants can be estimated. The estimates are shown in Table 4.16 and Table 4.17.

Table 4.17 shows that azo compounds represent 60% of the input of colorants for textile colouring, and further approximately 10% of the compounds are disposed or emitted.

Azo pigments represent approximately 14% of the fixated azo colorants. It is estimated that azo pigments only represent 5-10% of the trade in azo colorants for textiles. On this basis, 10% of the azo pigments will be assumed in the calculations of disposal.

Reactive dyes dominate the textile dyeing. This is because knitwear dyeing use one third of all azo dyes and is almost solely based on reactive dyes.

Assuming that azo dyes represent 70% of the consumed dyes (except from yarn dyeing: 50%), the dyeing industry uses approximately 350 tonnes of the azo dyes per year. 70 tonnes may be emitted to the waste water.

Pigments are mainly used in textile printing. They account for approximately 50 tonnes of azo compounds, of which 2 tonnes are not fixated.

It shall be noted that emissions from dyeing houses to the waste water are regulated by the authorities, and that treatment is obligatory. Consequently, most of the emission may not enter the municipal waste water treatment plants.

For some applications the total volume of colorants is known, but in some cases only the volume of dyed textile is available, cf. section 4.4.2. In these cases, the use is assumed to be 1 kg dyestuff per 100 kg textile. This is based on the fact that dyed textiles contain 0.05 to 3.0% dyestuff after the dyeing process (Kemi, 1997 and pers. comm., H.H. Knudsen, IPU, 1998).

Table 4.18 shows that the annual net imports of azo dyes are approximately 450 tonnes. 20% of the imported textile products come from Asiatic countries, which may use restricted azo colorants. However, it shall be noted that due to re-exportation, a percentage of the 450 tonnes will not be used in Denmark.

There may be a release of 70 tonnes of azo dyestuff from the dyeing process to untreated waste water, cf. Table 4.17. The main part of this release, 48 tonnes, comes from the large volume of colorants for knitwear dyeing, which mainly uses reactive dyes and has poor fixation rates (Heinfling et al, 1997; Miljøstyrelsen, 1994a). If knitwear dyeing is not taken into account, the release factor is approximately 9%.

A release factor of approximately 10% of the dyestuff is considered to be normal (Brown & Anliker, 1988). For this reason the above calculated loss of 70 tonnes may be a fairly realistic estimate.

The total supply of textiles for the Danish market may be estimated to be 117,000 tonnes (net imports 67,000 tonnes, see Table 4.18, and the Danish production of approximately 50,000 tonnes, see Table 4.13). Assuming that there is no accumulation of textiles, this amount is disposed of per year. With an average content of 1% colorant per tonne and assuming that 70% of the colorants are azo colorants, 1,170 tonnes of colorants are disposed of annually. 82 tonnes of these are pigments and 734 tonnes are azo dyes.

Approximately 212 tonnes of azo colorants may end up in landfills. The distribution between dyes and pigments is 190 tonnes and 20 tonnes, respectively, cf. chapter 2: Methodology.

The emissions from washing of textiles during the use phase are esti- mated as follows: With the above assumptions (117,000 tonnes of textile, 1% of colour content, 70% of azo compounds) and a lifetime loss of colour of 10%, there may be an annual loss of approximately 80 tonnes of azo colorants (72 tonnes dyes, Table 4.19, and 8 tonnes of pigments, Table 4.20) to the household waste water.

n.a. = negligible amount.

n.a. = negligible amount.

Paper

In Denmark five factories manufacture paper and two factories produce pulp. Four of the factories mainly use recycled paper as raw material (pers. comm.: L. Hjelm Jensen, Store Dalum A/S, 1998).

Paper recycling is well organised and accounts for 42% of the total paper consumption in Denmark. For some products, the content of colour is insignificant, but for other products the colorants have to be removed by a de-inking process. This process is carried out at two factories.

Supply and use in Denmark

The net imports of paper are 145,000 tonnes of which most are not coloured, except from whitening agents. In the Danish production of 450,000 tonnes of papers, colours are not used with the exception of whitening agents (pers. comm.: H.H. Knudsen, IPU, 1998).

Mass flow analysis

The ratio of coloured paper in the total paper import is estimated to be less than 5%. The content of colorants varies from 4.5 to 5.0 weight percent for dark colouring and 0.5 weight percent for bright colours (pers. comm.: H.H. Knudsen, IPU, 1998; Motschi, 1994).

The total amount of colorants in paper is approximately 150 tonnes, see Table 4.21. In the output analysis, this volume is assumed to be a maximum value, as an important share is constituted by inorganic pigments. The share of azo compounds in the 150 tonnes of colorants is unknown but is estimated to be 70%, corresponding to 100 tonnes.

42% of all paper products are recycled. 15% are disposed of to landfills and 43% incinerated. Consequently, 15 tonnes of the colorants in waste paper may end up in landfills. The amount of azo compounds in waste paper is unknown.

42 tonnes of colorants may be found in paper for recycling. When recycling paper products, colorants are removed or decomposed by different processes and trapped in a sludge, which is landfilled (21%), used as a filler in concrete (63%) or released to sludge for application in agriculture (16%) (Miljøstyrelsen, 1994b).

Presumably, all azo pigments in sludge used for manufacturing of concrete are decomposed in the production process. The remaining 37% of the colorants may contain some azo colorants, maximum 15 tonnes (100 tonnes Ž 42% Ž 37%).

n.a. = negligible amount.

Printing

Printing inks are used for printed matter, e.g.:

	newspapers, mostly printed on paper.
	printing on packaging materials like e.g. plastic foils or corrugated boards.

About 900 companies operate in the printing business or related trades. Imports and exports of printed matter of all kinds represent an important part of the total trade (Danmarks Statistik, 1997c).

In Table 4.23 an estimate is given for the use of printing inks and for imports and exports. The total production of printing inks is 10-11,000 tonnes and the total use is approximately 13,000 tonnes, see Table 4.23 (Miljøstyrelsen 1996a).

Black colours are obtained with carbon black, which is not an azo compound. Therefore, the following analysis concentrates on non-black colours, which represent 77% of the total use of printing inks, corresponding to 8,600 tonnes.

Almost 100% of the colorants in use are pigments.

It shall be noted that the 5,317 tonnes of non-black inks for flexography, ref. Table 4.23, may be overestimated (pers. comm.: Håkan Wallin, Arbejdsmiljøinstituttet, 1998). The overestimation may be 50% due to extensive use of a white non-azo colorant, TiO₂ (pers. comm.: E. Silberberg, Den Grafiske Højskole, 1998). Assuming that this overestimation of 50% is correct, the total use of non-black printing inks is approximately 6,000 tonnes or 70% of the total use.

Colorants for printing

Letterpress printing is today almost exclusively performed with offset printing inks. When necessary, the inks are slightly modified with printing auxiliaries.

These techniques are used for brochures, calendars, posters, business papers and packaging (carton and soft packaging). In typical inks the content of organic pigments is in the range 15-20 weight percent.

The primary application for flexographic printing is printing on paper for everyday use, such as paper sacks, shopping bags, wraps and polyolefin films for shopping bags and other packaging.

The content of organic pigments in flexographic inks for paper and film printing is 12-15 weight percent. As noted above TiO₂ accounts for half of the ink used.

This technique is used for printing on many kinds of materials, e.g. plastic items, textiles and electrical printed circuits.

The inks for publication gravure printing contain 8-15 weight percent of pigments. Only a few different pigments are used in publication gravure because this usually involves a four-colour process printing with standard colours.

Ink for packaging gravure printing on e.g. aluminium foils, rolls of paper, plastic films and laminated stock, is made of almost all types of organic pigments as in offset printing.

In offset printing inks, pigments are predominant. For a four-colour printing, a rather limited number of pigments is used, as most colours can be made from only three colours, red, yellow and blue. As black cannot be created by mixing of colours, the black colour is included in the four-colour system (Ullmann, 5^th Edition).

The black colour is normally carbon black. The blue colour may often be based on cyan, e.g. Pigment Blue 15:3. None of these are azo pigments.

The red colour, magenta, is usually made from an azo pigment, Pigment Red 57:1.

For obtaining a yellow colour, Pigment Yellow 12 and 13 are used.

Disazo resins are used as coatings for offset printing plates, as they are rather insensitive to changes in temperature and humidity. The disazo compound, most commonly used for negative plates, is a condensation product of 4-diazodiphenylamine salt with formaldehyde (Kirk-Orthmer, 1978).

Mass flow analysis

As black colour is mostly produced with the non-azo pigment carbon black, the following mass flow analysis only relates to non-black colours.

Mængde af ikke-sorte pigmenter i trykfarver.

Ref.: ¹ Miljøstyrelsen (1991).
² Miljøstyrelsen (1995).
In Table 4.24 a total use of 606 tonnes of pigments is calculated using process data as an entry.

Ref.: ¹ Table 4.24
² Danmarks Statistik (1997a).

1 Wasted ink from cleaning.
² Unused ink and wasted ink on recycled cotton pads.
³ 252 tonnes of pigments in de-inking sludge from recycled paper are divided into land- filling, soil improvement, and incineration in the next row of the table.
n.a. = negligible amount.

The waste water from offset printing houses may contain azo pigments, as especially the small printing companies remove ink from the dampening rollers with tap water and solvents. Data on the number of companies using this method as well as data on the release or concentration of pigments in the waste water are not available. For large plants other techniques are used.

The ratio of unused ink to input weight is approximated to 6% (Miljø-styrelsen, 1995) which adds up to 29 tonnes of azo pigments. Presumably, most of the pigments are disposed of in normal or special waste collection, thus, only a minor part of this may end up at landfills.

Approximately 200 tonnes of ink are lost in the cleaning process. Half of the ink is collected in a subsequent cleaning process for the cotton pads, and thereby the ink is destroyed. The other half is disposed with the waste (pers. comm.: Brian Lynggård, Berendsen Miljø, 1998). Thus, 7 tonnes of azo pigments are disposed in incineration (5 tonnes) or landfilling (2 tonnes).

A total of approximately 140 tonnes of azo pigments may end up at landfills and 40 tonnes of azo pigments are disposed in sludge for application in agriculture.

Accumulation of printed matter is estimated to be approximately 0 as the stocks of books etc. are assumed to be constant.

Paints and lacquers

Production and use of lacquers and paints account for the main part of the pigment consumption in Denmark. There is about 25 companies produ- cing paints etc.

Technical uses

The production of lacquers and paints was 130,000 tonnes in 1994 (Miljøstyrelsen, 1996a). According to the search conducted in the Product Register, 65% of the total consumption of colorants is used for production of paints. 10,000 tonnes of printing ink is accounted for in section 4.5.

The bulk of pigments constitute non-azo compounds: carbon black and titaniumdioxide. From interviewing the Danish manufacturers on their consumption of azo colorants, 56 azo colorants have been identified as being used in Denmark, 39 of these are pigments and 11 solvent dyes (see App. 1). It was not possible to establish a detailed picture of the quantities used.

Mass flow analysis

Ref.: Miljøstyrelsen (1996a), the Product Register and Danmarks Statistik (1997a).

In paints and lacquers 3,000 tonnes of azo colorants, almost solely pigments, are consumed per year.

It has not been possible to estimate the imports or exports of pigment on painted goods as it depends on the trade of goods, the type of product and surface area and the thickness of the paint layer.

Output

The actual application of the paint has great importance for the fate of the pigments:

	Outdoor paint may peel off due to wind and weather.
	Paint on wood may end at landfills or presumably be incinerated.
	Paint on walls may normally not be incinerated but rather end up at landfills.
	Paint on metal may end up in a melting oven, an incinerator or at a landfill.
	Paint on wall paper may be disposed of with common household waste.

Thus, it is difficult to present a qualified estimate of the fate of paint when disposed of. An estimate of the distribution of the disposal is shown in Table 4.29. This estimate is very likely to overestimate the actual amount, because an important part of the pigments used are carbon black and titaniumdioxide.

n.a. = negligible amount.

The fraction which is incinerated or melted down may not cause any release of azo pigments to the environment.

Mass balance

Based on the findings for the individual trades, the total mass balances for azo dyes and azo pigments are presented below.

Input

The production of azo dyes and pigments is shown in Table 4.30.

The total use of azo colorants and their distribution among trades are shown in Table 4.31 and Table 4.32.