1. 2 APPLIED PROCESSES AND TECHNIQUES
15.
The textile chain begins with the production or harvest of raw fibre. The basic steps in
this chain are schematically represented in the following diagram and will be described in
this chapter.
Figure 2.! : General diagramme of processes in textile industry

2. 2.1.9 Wool
Composition of wool
Wool is an animal hair from the body of sheep. This hair is normally
sheared once, or sometimes twice, a year and its quality and quantity varies
widely, depending on the breed of sheep and its environment. Wool is a
member of a group of proteins known as keratin, also found in horns, nails,
etc. In addition to wool fibre, raw wool contains:
• Natural impurities
- Wool grease 2-25% of greasy wool weight
- - Suint (dried perspiration) 2 - 12 % of greasy wool weight
- - Dirt ' 5-45% of greasy wool weight
- • Residues of insecticides, acaricides or insect growth regulators used
as veterinary medicines to protect sheep from ectoparasites, such as
lice, mites, blowfly, etc.
The percentage of the above-mentioned components may vary widely
depending on the origin of wool. For example, fine wool from merino
sheep, used mainly in apparel, typically contains 13 % wool grease,
whereas coarser wool of the types used for carpets contains an average of

3. about 5 % grease. The clean Fibre content of raw wool usually lies within
the 60 to 80 % range, but may vary from 40 to 90 %.
Wool grease is insoluble in water, but soluble in non-polar solvents such
as dichloromethane or hexane. Refined wool grease is a valuable by-
product.
Suint is water-soluble material arising from the secretion of the sweat
glands in the skin. Suint is soluble in polar solvent such as water and
alcohol.
Dirt can include a variety of materials such as mineral dirt, sands, clay,
dust and organic materials.
%
•Keratine 33
•Dirt 26
•Suint 28 (Dried perspiration)
•Fat 12
•Burrs 2-10 (Dried vegetable matter)
•Mineral matter 1
•Colouring matter 0.5-
Ectoparasiticides
have important implications for the discharge of raw wool
scouring effluent and disposal of the sludge generated by
the treatment of the effluent. The chemicals known to be
present in raw wool inciude:
• Organochlorine insecticides (OCs) -
-yHexachlorocyclohexane (Imdane)
Dieldrin
- DDT
• Organophosphorotis insecticides (OPs)
– Diazinon
– - Propetamphos
– - Chlorfenvinphos
– Chlorpyriphos
– Dichlorfenthion
20
• Synthetic pyrethroids insecticides (SPs)

4. - Cypermethrin
- Deltamethrin
- Fenvalerate Flumethrin
- - Cyhalothrin
- • Insect growth regulators (IGRs)
- - Cyromazine
- Dicyclanil
- - Difilibenzliron
- Triflumuron
The organochlorines are hazardous due to their persistence
and bioaccumulity. They are thus likely to have long-range
effects (in terms of both distance from the source and time
after release). y-Hexachlorocyclohexane (also called lindane)
is the most toxic (and also the most active as pesticide) of
the hexaclorocyclohexane isomers (alpha and beta-HCHs).
The technical crude product contains alpha- and beta-HCH,
the beta-isomer being the most persistent. Lindane and DDT
compounds are well-studied substances with demonstrated
endocrine disrupting capacity. The synthetic pyrethroid
insecticides show high aquatic toxicity (predicted no-effect
concentration for cypermethrin is estimated at 0.0001 ug/l,
while the corresponding value for the OPs diazinon and
propetamphos is 0.01 ug/l - UK environmental quality
standards expressed as annual average). Organophosphates
have lower aquatic toxicity than synthetic pyrethroids and
are less persistent than organochlorines. Nevertheless they
have high human toxicity (problems may therefore arise for
example, for dyers with steam volatile OPs) [279, L.
Bettens. 3001]. All major grower countries have banned the
use of organochlorine pesticides for sheep treatment, but
there is evidence that wool from some former Soviet Union
States and South America contain lindane at detectable
concentrations. This would suggest that either their grazing
is heavily contaminatd or that this compound continues to
be used occasionally for sheep treatment against
ectoparasites.

5. Wool from the majority of grower nations contains residual
sheep treatment medicines which are used legally to control
infestations of lice. ticks and mites. These materials may be
organophosphates, typically diazinon. propetamphos and
trans-chlorfenvinphos, synthetic pyrethroids, typically
cyperinethrin and insect growth regulators such as
cyromazine. The incidence of these materials on wool is
variable and depends on the permitted legal use pattern in
each country.
Manufacturers can use a database containing quantitative
information on the OC, OP and SP content of wool from
major producing countries. ENco maintains one such
database. Manufacturers use these data to avoid processing
wool from suspect sources. The system is of immediate
benefit to manufacturers who purchase and process wool
from known sources. Commission processors of either loose
fibre or yarn may not be aware of the origin of the Fibre
they are processing and so find it more difficult to control
their raw material inputs using this approach. More
information regarding ectoparasiticides is reported in Section
2.3.1 where the wool sourcing process is discussed.
Wool scouring
Environment issues
2.3.1.2 Environmental issues associated with wool
scouring (with water) This section discusses the
environmental issues associated with the overall scouring
process including the treatment of the process effluent. The
main environmental issues associated with the wool scouring
process arise from emissions to water, but solid waste and
the air emissions also need to be taken into account.
Potential for pollution of water
The removal of contaminants present on the raw fibre leads
to the discharge of an effluent in which the main polluting
contributors are:

6. • highly concentrated organic material in suspension and in
solution, along with dirt in suspension
• micro-pollutants resulting from the veterinary medicines
applied to protect sheep from external parasites.
There are also detergents in the discharged water, which
contribute to the increase of the chemical oxygen demand of
the effluent.
The detergent is recycled via the grease recovery/dirt
removal loop. As a result, low efficiency in this recovery
system is associated with higher amounts of detergent in the
effluent.
Compared to the chemical oxygen demand attributable to
wax, dirt etc.. the detergents can be considered minor
contributors to water pollution, but this is not the case
when harmful surfactants such as alkylphenol ethoxylates
are used as detergents (for more detail on environmental
issues regarding detergents, see Section 8.1).
As to the organic matter coming from wax and dirt.
according to "Stewart. 1988" the COD of effluent and of
greasy wool can be calculated using the following equation:
COD(mg/kg) - (8267 x siiint(%)) + (30980 x oxidised gi-
ease(%)) + (29326 x top grease(%)) + (6454 xdii-K%))+
1536. Since the coefficients for top grease and oxidised
grease in this equation are similar and since approximately
equal quantities of top grease and oxidised grease are
present in many wools, it is possible to combine the two
grease terms in the above equation as follows: COD (mg/kg)
= (8267 x suint(%)) +(30153 x total gi-ease(%)) + (6454 x
dirt(%)) + 1536 It is then possible to calculate the COD
content of "typical" merino and crossbred wools: 'l'op niv.isc
is'ui1»xidisci.l urease which is readily separated l'rom scour
liquors by centriluging: oxidised ~reiise is les li'-i.lropliol~i~
and is ICc rea~.ih' senarated Tclilvs Industry
28.
Cliiinti'r ". Merino wool: suint ~ 8 %, grease = 13 %: dirt =
15 % COD - (8.267 x 8) +(30.153 x 13) +(6.454x15)

7. +1.536 = 556 g/kg greasy wool Crossbred wool: suint = 8
"/(>'. grease = 5 %: dirt = 15 % COD - (8.267 , 8)
+(30.153 x 5) + (6.454 x 15)+1.536 = 315 g/kg greasy
wool.
These high levels of oxygen-depleting substances must be
removed from the effluent before it can be discharged to the
environment without potential for harmful effects.
Organohalogen. organophosphorus compounds and biocides
are among the priority substances listed for emission control
in the IPPC Directive. Worldwide, the most common
ectoparasiticides used for treating sheep are diazinon (OP),
propetamphos (OP). cypermethrin (SP) and cyromazine (fly-
specific IGR), for control of blowfly. Insect growth regulators
such as dicyclanil, diflubenzuron and triflumuron are
registered only in Australia and New Zealand.
Organochlorine pesticides (in particular,
iii.•a~.•.lnln>~-Li~llil.'<~ln.~ (ii'i. siin ruLil'id oii wool
coining noiii inc ionnei Soviel utiion. lhe Middle East and
some South American countries [187, INTERLAfNE, 1999]
(see also Section 2.1.1.9).
Concerning the fate of ectoparasiticides when they enter the
scouring process, a distinction has to be made between
lipophilic and hydrophylic compounds such as cyromazine.
The lipophilic compounds - OCs, OPs and SPs - associate
strongly with the wool grease and are removed with it
during scouring (although a fraction -up to 4 %-is retained
by the fibre and will be released in the subsequent finishing
wet processes). This behaviour applies also to diflubenzuron
(IGR). Recent studies have shown that triflumuron (IGR)
associates partially with the dirt and partially with the
grease. As a result, compared to other lipophilic compounds,
a higher proportion of this pesticide is likely to be retained
on-site (on the wool fibre and on the recovered wool grease
and dirt) and not be discharged in the aqueous effluent
[103, G. Savage, 1998]. On the contrary. IGRs such as
cyromazine and dicyclanil are appreciably water-soluble (I I

8. g/l at 20 °C, for cyromazine). which means that they are not
removed in wool grease recovery systems.
In the waste water treatment systems an additional fraction
of the pesticide residues is removed. Physico-chemical
separation techniques remove the biocide residue at
approximately the same rate as the grease and the dirt with
which they are associated. On the other hand, evaporation
system removes Ocs and SPs in significant quantities. But
upto 30% of Ops may appear in the condensate because
they are steam volatile. The water-soluble compounds, such
as the IGR cyromazine are probably not removed from the
effluent stream except by evaporating treatments [187.
INTI-;RI.AINF.. 1999].
Despite these treatments, the removal of pesticides is often
incomplete and there is potential for pesticides to enter the
aquatic environment when the effluent is discharged. The
environmental concentrations of ectoparasiticides in the
receiving water depend greatly on local circumstances, in
particular, the amount of scouring activity concentrated in a
given catchment and the dilution available between scouring
discharges and the river which receives the treated effluent.
In areas of Europe with a high concentration of scouring
activity, there is a risk of high concentration levels of
pesticides in the receiving water. In this case, it is preferable
to define discharge limits on the basis of risk assessment
models. In UK. for example, statutory environmental quality
standards (EQS) for the OCs and non-statutory standards for
the OPs and cypermethrin have been defined. Discharge
limits are set up for processing mills by comparing the given
EQS targets with predicted environmental concentrations
based on tonnage of wool processed and typical effluent
treatment systems.
29.
The control of the discharge limits at the scouring mills is
carried out by using data From the ENco Wool & Hair
Pesticide database (to define the initial amount of residues
on the incoming wool) in combination with the above-

9. mentioned water-grease partition factors for the different
pesticides. For more detailed information see also Sections
2.1.1.9 and 32.1 ("Ectoparasiticides").
Potential for pollution of land
Two main "wastes", grease and sludge, are produced as a
consequence of scouring activities (and related effluent
treatment). Depending on its oxidation extent, it may be
possible to recover from 20 to 40 % of the grease initially
present on the raw wool. This is to be regarded as a by-
product rather than a waste, since it can be sold to lanolin
refiners for the production of high-value products in the
cosmetic industry. However, high levels of pesticides
residues in the grease can also be a problem for the lanolin
refiners, especially for the production of lanolin-based
pharmaceuticals and cosmetics. since more expensive and
sophisticated techniques have to be used to reduce the
pesticides to acceptable levels. Acid-cracked grease has no
market value and has to be landfilled. The sludge produced
as a result of physico-chemical treatment of waste water
also contains grease, dirt and the portion of pesticides which
are strongly associated with either grease or dirt.
Concentrates and sludges from evaporation or membrane
filtration may also contain suint. which is mainly potassium
chloride and potassium salts of fatty acids. Suint is a by-
product which can be used in agriculture.
Sludge and concentrate disposal may follow several routes:
• incineration (with heat recovery)
Pyrolysis/gasifi cation
• brick manufacturing
• composting or co-composting with other organic material
• landfill.
The first three sludge disposal routes destroy the organic
material in the sludge, including grease and pesticides. The
ash from incineration may contain potassium salts, derived
from suint, and heavy metals characteristic of the soil on

10. which the sheep producing the wool have grazed. The ash is
normally disposed of to landfill.
The characteristics of the char from pyrolysis/gasification are
unknown and this char is also typically disposed of to
landfill. The use of wool scour sludges in brick manufacture
results in no residues for immediate disposal.
These three sludge disposal methods probably have the
least potential to pollute land.
Wool scour sludges cannot be composted alone, but require
the addition of carbon-rich organic material. Green waste
from agriculture or horticulture has been used.
Composting is not yet regarded as a fully developed, fail-
safe technique and only partly degrades the pesticides
present in the sludge. However, since the pesticides present
in the sludge are there because of their lipophilicity or their
strong propensity to absorb onto solids, they are likely to be
immobile in soil. and spreading of compost derived from
wool scour sludges on agricultural land is unlikely to pose an
environmental risk of any significance. Landfill is the
simplest and often cheapest method of disposal of sludges.
In the longer term. however, landfill is not believed to be
either economically or environmentally sustainable. The fate
of wool scour sludges in landfill is not known, but there is a
small potential for the cctoparasiticides present to arise in
leachate. Anaerobic degradation of the organic material in
the sludge will give rise to methane emissions [187,
INTERLAINE, 1999]. l'exiiles Industry 29
30
Potential for pollution of air
Air pollution is not a main issue for wool scouring processes.
Nevertheless two issues can be mentioned. Hot acid
cracking, which involves heating the scour effluent with
sulphuric acid, when used near residential areas, has been
the subject of odour complaints. Incineration is used in
conjunction with evaporation of the effluent because the

11. surplus heat from the incinerator can be used in the
evaporation process. Incineration of wool scour sludges has
potential for air pollution. Since sludges contain relatively
high levels of chloride (from suint) as well as organically
bound chlorine from ectoparasiticides etc., there is potential
for the production of polychlorodibenzodioxins and furans,
when they are incinerated (catalytic and high temperature
incinerators are now available to prevent these emissions).
The sludges also contain relatively high levels of sulphur
and nitrogen and (the combustion process therefore
produces SOx and N0x. Dust and odours should also be
taken into account.
2.3.1.3 Cleaning and washing with solvent
2.3.1.4 Environmental issues associated with wool
scouring (with organic solvent)
The Wooltech system described above, uses
trichloroethylene as solvent. Trichlorethylene is a non-
biodegradable and persistent substance (trichloroethylene is
on the EPER list). Unaccounted losses of this solvent arising
from spills, residues on the fibre, etc., if not adequately
treated to destroy the solvent, may lead to diffuse emissions
resulting in serious problems of soil and groundwater
pollution. As far as water and energy consumptions are
concerned, the Wooltech system shows lower consumption
levels compared to a typical scouring process using water. A
more accurate balance of the inputs and outputs in this
process is reported in Section 3.2.2.
33.
Figure Take from original text
2.6.2 Wool preparation before colouring
Carbinsing
Scouring, Drycleaning
Fulling
Bleaching

12. 2.6.2.2 Environmental issues
Wool pretreatment gives rise mainly to water emissions,
although there are also specific operations (e.g. carbonising
with the "Carbosol" system and dry cleaning) where
halogenated organic solvents solvents can produce not only
emissions to air, but also contamination of soil and
groundwater if their handling and storage is not done using
the necessary precautions. Preventive and end-of- pipe
measures include closed-loop equipment and in-loop
destruction of the pollutants by means of advanced
oxidation processes (e.g. Fenton reaction). See Sections
4.4.4. 4.9.3 and 4.10.7 for more detailed information. The
process also involves the generation of exhausted active
carbon from the solvent recovery system. This solid waste
has to be handled separately from other waste material and
disposed of as hazardous waste or sent to specialised
companies for regeneration. Due to the predominantly batch
nature of wool pretreatment operations for all types of
make- ups, (the resulting emissions will be discontinuous
and with concentration levels largely influenced by the liquor
ratios used. An exception is represented by carpet yarn
which can be scoured/ bleached and mothproofed on tape or
"package to package" scouring machines (see Section 2.
14.5. 1 .2) giving rise to continuous flows.
53
The pollutants that can be found in the waste water,
originate in part from the impurities that are already present
on the fibre when it enters the process sequence and in part
from the chemicals and auxiliaries used in the process.
Pollution originating from impurities present on the
raw material
Residues of pesticides used to prevent the sheep becoming
infested with external parasites can still be found on scoured
wool in amounts, which depend on the efficiency of the

13. scouring process. These are mainly organophosphates (OPs)
and synthetic pyrethroid (SPs) insecticides and insect growth
regulators (IGRs), but detectable residues of organochlorine
pesticides (OCs) can be observed. They partition between
the fibre and the water according to their stronger or weaker
lipophylic character and, as a consequence, traces of these
compounds are released in the waste water. More
information about ectoparasiticides can be found in Sections
2.1.1.9 and 2.3.1.2. The partition factors of the different
classes of pesticides are discussed in more detail for the
carpet sector in Sections 3.4.1.1 and 3.4.1.2. Note that
because of their steam volatility some pesticides (OPs) end
up in the air emissions from open machines. This must be
taken into account in input/output balances. Spinning
lubricants (see 8.2.3), knitting oils (see 8.2,5) and other
preparation agents also represent an important issue in wool
pretreatment. These substances are removed during the
scouring process, contributing to the COD load and aquatic
toxicity in the final effluent.
The main concerns are about:
• poorly refined mineral oils (content of aromatic
hydrocarbons)
• APEO (non-biodegradable and giving rise to toxic
metabolites)
• silicones (non-biodegradable and difficult to remove
without scouring assistants)
• biocides (toxic to aquatic life).
The dry spinning route in the carpet sector, described in
Section 2.14.5.1. represents one exception because in this
case spinning lubricants do not reach the water effluent.
Pollution originating from chemicals and auxiliaries
used in the process
Considerable amounts of surfactants are used in
pretreatment as detergents, wetting agents, etc.
Surfactants with good biodegradability with acceptable
performance are now available (see Section 4.3.3).
Nevertheless, the use of alkylphenol ethoxylates is still

14. common in some companies due to their low cost.
Alkylphenol ethoxylates (APEOs) and in particular
nonylphenol ethoxylates (NPEs) are under pressure due to
the reported negative effects of their metabolites on the
reproduction system of aquatic species.
The environmental issues arising from surfactants in
common use are discussed in Section 8.1.
Other pollutants of concern that may be found in water
effluent from pretreatment activities are:
• reducing agents from bleaching treatments and chemical
setting of carpet wool yarn (sodium metabisulphite): they
contribute to oxygen demand in the waste water
• poorly bio-eliminable complexing agents (e.g. EDTA, DTPA,
phosphonates) from hydrogen peroxide stabilisers, etc.
• AOX from sodium hypochlorite bleaching
• insect-resist agents in wool carpet yarn production. More
details regarding environmental issues associated with the
above-mentioned substances are given elsewhere in this
document, in particular in Section 2.6.1.2 and Section 8.5.