During the past 15 years, various schemes have been developed for ecotoxicological assessment and classification. These include the Dutch General Assessment Methodology in the Netherlands (RIZA-Concept), the SCORE-System in Denmark, the BEWAG-Concept in Switzerland and the TEGEWA scheme developed in Germany by industry in collaboration with authorities.

Three of these schemes -- the TEGEWA scheme, the SCORE-System and the Dutch General Assessment Methodology -- have been proposed by the German, Danish and Dutch TWG members, respectively, as techniques to be considered in the determination of BAT. All three methods are presented in Section 13 (extracts of submitted documents).

All three sources regard the proposed schemes as useful tools that allow the user to select textile dyes and auxiliaries for ecotoxicological aspects. Indirect benefits for water quality are therefore expected, although difficult to quantify/evaluate.

According to TEGEWA, the introduction of the method in Germany in 1998 has produced a reduction in the consumption of Class III products (products with «High relevance to waste water, according to TEGEWA classification scheme). This is shown in the table below.

	Number				Quantity (t/yr)				Quantity (%)
	1997	1998	1999	2000	1997	1998	1999	2000	1997	1998	1999	2000
Class I	2821	3020	3242	3164	98446	105983	102578	104406	63	67	75	77
Class II	1499	1485	1358	1258	29972	29422	23321	22103	19	18	17	16
Class III	460	417	358	297	27574	23830	10231	9206	18	15	8	7
Total	4780	4922	4958	4719	155992	159235	136130	135715	100	100	100	100

Table 4.7: Textile auxiliaries sold in Germany from 1997 to 2000: number, quantity and percentage of textile auxiliaries in classes I, II, III, according to TEGEWA

None believed likely according to both sources. However, some considerations are worth mentioning:

From the user/textile finisher point of view, the implementation of the TEGEWA method does not require particular resources to be spent because the chemical producers classify of the products.

Conversely, the implementation of the Danish SCORE-System implies that the authorities and the companies allocate the necessary man-hours to set up the system. Once the company has joined the system, approximately 25 - 50 man-hours a year are needed for maintenance of the system [192, Danish EPA, 2001].

The broad applicability of this kind of tool at the European level depends on the degree of acceptance of the method by the parties involved (i.e. industry and national authorities).

According to the sources, no major economic problems have been encountered in Germany or in Denmark, where the two proposed classification tools are already applied.

The TEGEWA scheme has been applied in Germany since 1998, while the implementation of the SCORE-System is part of the environmental permits for the clothing and textile industry in Ringkjobing in Denmark.

[192, Danish EPA, 2001], [37, TEGEWA, 2000], [179, UBA, 2001] with reference to:

Konzipierung eines Verfahrens zur Erfassung und Klassifizierung von Textilhilfsmitteln

Abschlussbericht FKZ 10901210 zu einem Forschungsvorhaben im Auftrag des Umweltbundesamtes (1996) - nicht veröffentlicht

Official and published self-commitment concerning the classification of textile auxiliaries according to their waste water relevance, dated 27.11.1997 (1997)

4.3.2 Emission factor concept (emissions to air)

The emission factor concept embraces the emissions of volatile organic carbon and dangerous substances that are potentially found in the exhaust air from heat-setting, thermosol process, impregnation and fixation of finishing agents. The concept was developed in Germany by public authorities (national and federal states level) in co-operation with the German Association of textile finishing industry (TVI-Verband) and TEGEWA «LAI, 1997».

The fundamental principle of this concept is that in most cases the emissions produced by the single components in the auxiliary formulations are additive. As a result the emission potential of each recipe can be calculated on the basis of emission factors given for the single substances present in the formulation (for certain substances, however, the correlation between emission and process parameters is more complex).

As described earlier in Section 3.3.3.5.6, the substance-based emission factor (fc or fs) is defined as the amount of substances (organic or inorganic) in grams that can be released at defined process conditions (curing time, curing temperature and type of substrate) from one kilogram of auxiliary. There are two types of substance-based emission factors: 1) fc, which gives the total emission produced by the organic substances present in the formulation, expressed as total organic carbon; 2) fs, which gives the emission attributable to specific toxic or carcinogenic organic substances or to inorganic compounds, such as ammonia and hydrogen chloride, etc. present in the formulation.

In Germany, where the technique is widely applied, the substance-based emission factors are provided to the finisher by the auxiliary supplier, in addition to the information reported in the Material Safety Data Sheets. The factors are based on measurements, calculations or conclusions made by analogy (according to TEGEWA guidance for calculation of substance-based emission factors) [287, Germany, 2002].

The textile substrate-based emission factor (WFc or WFs) is defined as the amount of organic and inorganic substances in grams that can be released as defined process parameters (curing time, curing temperature and type of substrate) from one kilogram of textile treated with a given auxiliary formulation. The textile substrate-based emission factor can be calculated on the basis of the emission factors of the individual components of the formulation/recipe (fc or fs), their concentration in the liquor (FK) and the liquor pick-up. One example of calculation of the textile-based emission factor is reported in Table 3.44.

The calculated textile substrate-based emission factors WFc/s can then be compared with the limit values for textile substrate-based emission factors set by environmental authorities (referred to a standard air-to-textile substrate ratio of 20 m³ air/kg textile substrate).

The concept can be regarded as a system to control and prevent air emissions from textile finishing. The auxiliary-based substance emission factor makes it possible to predict the emissions of a given recipe based on the emission factors of the single components. In this way the operator knows the emissions of his process before carrying it out. He can therefore concentrate at the product and process design stage on minimising the emissions at the source, for example by reducing the amount of auxiliaries or selecting auxiliaries with lower emission potentials.

The control of the air emissions of the recipes/formulations for finishing by pre-calculation of the textile substrate-based emission factors should be done regularly (at least once a year) and specially before using a new recipe or changing compounds of an existing recipe.

The following reflects the air emission values related to an air/ textile substrate ratio of 20 m/kg, applied in Germany and achievable thanks to the application of the Emission Factor Concept:

All substances belonging to class I (3.1.7 TA-Luft) exceeding 500 ppm in the auxiliary formulation have to be declared. In addition, information on substances classified under item 2.3 TA-Luft (carcinogenic substances) exceeding 10 ppm is obligatory («TA-Luft, 1986»).

Substances or preparations which are classified as carcinogens, mutagens or toxic to reproduction under Directive 67/548 EEC as last amended by Directive 1999/33/EG and last adapted by Directive 2000/33/EG, are assigned or need to carry the risk phrases R45, R46, R49, R60, R61 shall be replaced as far as possible by less harmful substances or preparations within the shortest possible time.

However, it has to be kept in mind as a general consideration, that the use of a factor makes access to the accumulated information difficult, unless it is fully disclosed [281, Belgium, 2002].

The emission factor concept is of general applicability in textile mills and is especially suitable for facilities performing chemical finishing treatments and thermosol processes.

This technique is widely applied in Germany, where it is accepted by the environmental authorities. For other countries the application of the emission factor concept depends entirely on the national competent bodies.

There are no costs for the textile finisher apart from the cost of calculating the emission factors for the finishing recipes used in the process, which is negligible. A correct selection of low- emission auxiliaries can significantly reduce costs for air emission abatement.

Pre-calculation of emissions enables the finisher to take actions in order to meet the emission limit values set by environmental authorities.

In Germany, where the emission factor concept is accepted by the environmental authority, an important driving force for implementing this technique has been the possibility that it gives of avoiding or reducing expensive emission measurements (pre-calculation).

4.3.3 Substitution for alkylphenol ethoxylates (and other hazardous surfactants)

Many surfactants give rise to environmental concerns due to their poor biodegradability, their toxicity (including that of their metabolites) and their potential to act as endocrine disrupters.

Concerns currently focus on alkylphenol ethoxylates (APEO) and in particular on nonylphenol ethoxylates (NPE), which are often contained in the formulations of detergents and many other auxiliaries (e.g. dispersing agents, emulsifiers, spinning lubricants).

Alkylphenol ethoxylates are themselves believed to be endocrine disruptors and to cause feminisation of male fish. More importantly, however, they produce metabolites which are believed to be many times more potent as endocrine disruptors than the parent compounds. The most potent of these are octyl- and nonylphenol. Nonylphenol is listed as a priority hazardous substance under OSPAR and the EC Water Framework Directive, which means that any discharge needs to be phased out.

Alkylphenol ethoxylates may be present in auxiliaries formulations as the main active substances or in small percentages as additives. In both cases substitutes are available. The main alternatives are alcohol ethoxylates (AE), but other readily biodegradable surfactants have also been developed.

As to other problematic surfactants, substitutes are often available that are readily biodegradable or bioeliminable in the waste water treatment plant and that do not form toxic metabolites.

Substances are considered readily biodegradable if in a 28-day period, with ready biodegradation studies (OECD 301 A-F), the following levels of degradation are achieved:

Substances are considered bioeliminable if the following levels of degradation are achieved:

The finisher should be able to select the less hazardous products based on the information reported by the manufacturer on Material Safety Data Sheets.

The use of APEO-free auxiliaries produces a reduction of the amount of potentially toxic endocrine disrupters in the receiving water. Moreover, the substitution of non-bioeliminable surfactants will result in improved treatability of the effluent.

Sites using exclusively APEO-free auxiliaries report no operational or processing difficulties [32, ENco, 2001].

For the substitution of APEO in detergents, the new washing formulations are reported to be applied in concentrations similar to the conventional ones [180, Spain, 2001].

According to other sources (e.g. [187, INTERLAINE, 1999]), AE are slightly less effective detergents than APEO, which means that higher concentrations and feed rates may be required for equivalent effects. Investigations carried out in the wool scouring sector showed that mills using alkyl phenol ethoxylates used an average of 7.6 g detergent per kg greasy wool (range 4.5 - 15.8 g/kg), while the users of alcohol ethoxylates consumed an average of 10.9 g detergent per kg greasy wool (range 3.5 - 20 g/kg).

The possibility of foaming in rivers exists in cases where sufficient amounts of surfactant pass through sewage treatment works unchanged or as partial metabolites with residual surfactant properties. The formation of foam is, however, typical of many other surfactants, including APEO.

This measure is generally applicable in all new and existing wet processing installations. However, as long as «hard» surfactants are used in fibre and yarn preparation agents, a large fraction of potentially hazardous surfactants in wet-processing effluents cannot be controlled by the dyehouse.

For APEO, it should be noted that these surfactants also have many dry applications (e.g. as dry spinning lubricants, in the production of viscose for technical uses). In these cases substitution is possible, but it is expensive and it is not a priority. Indeed, here the presence of APEO can be regarded as a less critical problem since the surfactant does not enter the wet processing line.

AE are 20 - 25 % more expensive than APEO. The fact that they appear to be less effective can further increase the operating costs over those of APEO. However, mills making the change from APEO to AE are more likely to take care to optimise their use [187, INTERLAINE, 1999].

An example is given for a UK scouring mill which made the substitution in 1996. Annual costs for detergent use were estimated to have increased from EUR 84700 to EUR 103600: an increase equivalent to about EUR 1.09 per tonne of wool processed. In the past few years the cost of APEO has been reduced significantly from EUR 1000/tonne (1997/98) to EUR 700/tonne (1999). As a result the increase in costs involved with the use of AE could be even higher [187, INTERLAINE, 1999].

Generally speaking, costs of environmentally optimised formulations are comparable, but in some cases can be significantly higher than conventional products. However, usually the finisher tends to accept the extra costs associated with the use of more environmentally friendly products, especially when the overall environmental balance is considered [179, UBA, 2001].

The enforcement of regulations at national and European level, together with the PARCOM recommendations and the eco-labelling schemes, are the main driving forces.

[187, INTERLAINE, 1999], [32, ENco, 2001], [179, UBA, 2001], [180, Spain, 2001], [51, OSPAR, 1994] with particular reference to P010, P011, P012, [61, L. Bettens, 1999].

4.3.4 Selection of biodegradable/bioeliminable complexing agents in pretreatment and dyeing processes

Complexing agents are applied to mask hardening alkaline-earth cations and transition-metal ions in aqueous solutions in order to eliminate their damaging effect, especially in pretreatment processes (e.g. catalytic destruction of hydrogen peroxide), but also during dyeing operations.

Typical sequestering agents are polyphosphates (e.g. tripolyphosphate), phosphonates (e.g. 1-hydroxyethane 1,1-diphosphonic acid) and amino carboxylic acids (e.g. EDTA, DTPA, and NTA) (see figure below).

Figure 4.6: Chemical structure of some N- or P- containing complexing agents

The main concerns associated with the use of these substances arise from, their N- and P- content, their often-low biodegradability/bioeliminability and their ability to form stable complexes with metals, which may lead to remobilisation of heavy metals (see also Section 8.5).

Softening of fresh water, to remove the iron and the hardening alkaline-earth cations from the process water, and the techniques described in Section 4.5.6 are available options for minimising/ avoiding the use of complexing agents in various applications (e.g. in hydrogen peroxide bleaching, rinsing after reactive dyeing of cotton).

When complexing agents are used, polycarboxylates or substituted polycarboxylic acids (e.g. polyacrylates and polyacrylate-maleic acid copolymerisates), hydroxy carboxylic acids (e.g. gluconates, citrates) and some sugar-acrylic acid copolymers are convenient alternatives to the conventional sequestering agents. None of these products contains N or P in their molecular structure. In addition, the hydroxy carboxylic acids and sugar-acrylic acid copolymers are readily biodegradable.

The best complexing agent (in a technical, economical and ecological sense) is one that also achieves a good balance of ecological properties and effectiveness and has no detrimental effect in dyeing (demetalisation of dyes).

Effectiveness is measured as the capacity to complex alkaline-earth cations, the dispersing capacity and the capacity of stabilising hydrogen peroxide.

A qualitative assessment of the ecological properties of most common classes of complexing agents is given in Table 4.8, while Table 4.9 gives an analysis of the aspects related to their effectiveness.

Ecological property	EDTA, DTPA	NTA	Poly-phosphate	Phosphonates	Poly-carboxylates	Hydroxy carboxylic acid	Sugar copolymers
Biodegradability	No	Yes	Inorganic	No ⁽¹⁾	No	Yes	Yes
Bioeliminability	No	-	-	Yes ⁽²⁾	Yes	-	-
N-content	Yes	Yes	No	No	No	No	No
P-content	No	No	Yes	Yes	No	No	No
Remobilisation of heavy metals	Yes	No	No	No	No	No	No
Source: [179, UBA, 2001] Notes: (1) [179, UBA, 2001] with reference to «Nowack, 1997» (2) under UV photocatalytic degradation is observed

Table 4.8: Qualitative assessment of commercially available complexing agents

The substitution of conventional complexing agents with the product mentioned above has the following positive effects:

Complexing agents are applied in many different fields in textile chemistry. Recipes and application techniques are therefore process-specific. However, the use of the optimised products mentioned above does not imply major differences with respect to conventional complexing agents.

Bioelimination/biodegradation rates for some commercial products that do not contain P and N in their molecular structure are:

NTA is biodegradable when treated in waste water treatment plants under nitrifying conditions (OECD 302B, elimination 98 % COD: 370 mg/g; BOD 30: 270 mg/g - «BASF, 2000»). Recent studies have shown that NTA plays a minor role, if any, in the remobilisation of heavy metals in aquatic sediments [280, Germany, 2002]. Phosphonates are not biodegradable, but they are bioeliminable and they do not contribute to the remobilisation of heavy metals (see also Section 8.5).

Taking as a reference the application of conventional complexing agents, there are no cross-media effects of concern. With polyacrylate-based complexing agents, the residual monomer content in the polymer should be taken into account (note that acrylates are also widely used in large volume in other sectors as detergent builders, thus overloading the waste water treatment plants more significantly than textile effluents do).

The complexing agents described in this section can be used in continuous and discontinuous processes. The effectiveness of the various products has, however, to be considered when replacing conventional complexing agents by more environmentally-friendly ones (see table below).

Property	EDTA, DTPA	NTA	Poly-phosphate	Phosphonate	Poly-carboxylates	Hydroxy carboxylic acid	Sugar copolymers
Softening	+	+	+	++	+	0	+
Dispersing	-	-	0	+	+	-	+
Stabilisation of peroxide	+	-	-	++	0	-	+ (special products)
Demineralisation	++	+	0	++	0	0	0
Source: [179, UBA, 2001] Note: effectiveness increases in the following order -, 0, +; ++

Costs for N- or P-free compounds, especially for sugar-acrylic copolymers, are comparable to other N- and P-free products, although higher quantities may be necessary in some cases, [179, UBA, 2001].

The enforcement of regulations at national and European level, together with the PARCOM recommendations and the eco-labelling schemes, are the main driving forces.

N- and P-free complexing agents are applied in many plants world-wide. Consumption of polycarboxylates is significantly higher than for sugar-acrylic copolymers and hydrocarboxylic acids [179, UBA, 2001].

[61, L. Bettens, 1999], [169, European Commission, 2001], [179, UBA, 2001] with reference to:

4.3.5 Selection of antifoaming agents with improved environmental performance

Excessive foaming causes uneven dyeing of yarn or fabric. There is a trend towards higher consumption of defoamers because of the growing preference for high speed and high temperature processing, reduction in water usage and continuous equipment/processes. Anti-foaming agents are commonly applied in pretreatment, dyeing (especially when dyeing in jet machines) and finishing operations, but also in printing pastes. Low foaming characteristics are particularly important in jet dyeing, where agitation is severe.

Products that are insoluble in water and have a low surface tension are suitable for providing antifoaming effect. They displace foam-producing surfactants from the air/water boundary layer. Nevertheless, antifoaming agents contribute to the organic load of the final effluent. Their consumption should therefore be reduced in the first place. Possible measures in this respect are:

However, these techniques are not always applicable and cannot completely avoid the use of defoamers. Therefore the selection of auxiliaries with improved ecological performance is important. Antifoaming agents are often based on mineral oils (hydrocarbons). The presence of PAHs contaminants must also be taken into account when poorly refined oils are present in the formulation.

Environmentally improved products are free of mineral oils and are characterised by high bioelimination rates.

Typical active ingredients of alternative products are silicones, phosphoric acid esters (esp. tributylphosphates), high molecular alcohols, fluorine derivatives, and mixtures of these components.

Thanks to the use of mineral oil-free defoamers the hydrocarbon load in the effluent, which is often limited in national/regional regulations, is minimized. Furthermore, these alternative defoaming agents have lower specific COD and higher bioelimination rate than hydrocarbons. For example, a product based on triglycerides of fatty acid and fatty alcohol ethoxylates (COD: 1245 mg/l; BOD₅: 840 mg/l) has a degree of bioeliminability higher than 90 % (determined in the modified Zahn-Wellens-Test, according to OECD 302 B Test method or EN 29888, respectively) [179, UBA, 2001].

For air emissions, due to the substitution of mineral oil-based compounds, it is possible to reduce VOC emissions during high-temperature processes (caused by the carry-over of antifoaming agents on the fabric after wet operations).

The mineral oil-free defoamers can be used in a way similar to conventional products. Because silicone products are highly effective, the required amount can be considerably reduced.

There are no particular limitations to be mentioned concerning the application of the mineral oil-free formulations. However, the effectiveness of the various alternative products has to be borne in mind [179, UBA, 2001].

If antifoaming agents based on silicones are used there is risk of silicone spots on the textile and silicone precipitates in the machinery [179, UBA, 2001].

Restrictions in the use of silicones in some sectors have to be considered. For example, in the automotive industry restrictions have been put in place, which forbid the use of silicones in automobiles and textiles for this industry.

Cost of mineral oil-free products is comparable to conventional ones [179, UBA, 2001].

Minimisation of hydrocarbons in the effluent is the main reason for substituting mineral oil-containing antifoaming agents.

Many plants in Europe. There are various suppliers for antifoaming agents free of mineral oils.

Optimierung von Textilhilfsmitteln aus ökologischer Sicht. Möglichkeiten und Grenzen

4.3 Selection/ substitution of chemicals used

4.3.1 Selection of textile dyes and auxiliaries according to their waste water relevance

4.3.2 Emission factor concept (emissions to air)

4.3.3 Substitution for alkylphenol ethoxylates (and other hazardous surfactants)

4.3.4 Selection of biodegradable/bioeliminable complexing agents in pretreatment and dyeing processes

4.3.5 Selection of antifoaming agents with improved environmental performance