Best Available Techniques in the Textile Sector
Brigitte ZietlowGerman Federal Environment Agency
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Outline
Overview over textile industry in Europe
Status of the BREF Textile Industry
Examples for Best Available Techniques
Conclusions
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Overview over the European Textile & Clothing sector
Companies(number)
Employment(1000 Pers.)
Turnover(bil. €)
Extra‐EU imports (bil. €)
Extra‐EU exports (bil. €)
Extra‐EU tradebalance (bil. €)
Man‐madefibres
78 21 9,6
textile 53.887 674 80,6 24,4 21,8 ‐2,7
clothing 127.457 1.085 75,1 65,2 20,3 ‐44,9
total 181.423 1.780 165,3 89,6 42,1 ‐47,6Quelle: Euratex
• T&C industry is among the largest industrial branches in the EU• Predominantly small and medium-sized enterprises• second world exporter in textiles and clothing (26% of global
sales)• largest world market for textile and clothing products (household
consumption of nearly 500 Billion Euro/year)
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Overview over the European Textile & Clothing sector
Quelle: Eurostat
32,5%
16,3%
9,7%6,8%4,2%
30,5%
Main textile suppliers for the EU
China
Turkey
India
Pakistan
USA
others
42,7%
13,1%13,1%
6,2%
3,2%21,7%
Main clothing suppliers for the EU
China
Bangladesh
Turkey
India
Tunisia
others
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Overview over the European Textile & Clothing sector
Italy, France, UK, Germany and Spain accounting for about three quarters of EU production of textiles and clothing
European producers are world leaders in markets for technical/industrial textiles and non-wovens (for example industrial filters or products for the automotive industry or the medical sector), as well as for high quality garments with a high design content
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Overview over the European Textile & Clothing sector
45%
14%
12%
8%
4%2% 15%
The share of the main types of fibres used in the textile finishing industry
cottonpolyesterviscosewoolacrylicsilkothers
Quelle: BREF Textile industry
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Overview over the European Textile & Clothing sector
45%
20%
18%
10%7%
The main categories of processed goods of the EU textile finishing industry
clothing textileshousehold textilestechnical textilesinterior textilesothers
Quelle: BREF Textile industry
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Status and scope of the BREF Textile Industry
The BREF Textile Industry is the major outcome of the European information exchange on BAT for the sector
The BREF provides a lot of information on available techniques
First issue of the BREF Textile Industry published in 2003
Revision is planned for 2015• In Germany information exchange has started
in 2009 already
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Status and scope of the BREF Textile Industry
• Scope: Textile finishing operations where the treatment capacity exceeds 10 tonnes per day
• Additionally included: Upstream processes with
influence on the environmental impact of finishing processes
backing of carpets
Fibre manufacturing: Natural fibres/Man-made fibresFibre manufacturing: Natural fibres/Man-made fibres
Spinning of fibres Yarn manufacturingSpinning of fibres Yarn manufacturing
weaving, knitting, non-woven technologiesCloth manufacturingweaving, knitting, non-woven technologiesCloth manufacturing
Finishing processespretreatment, dyeing, printing, coating, finishingFinishing processespretreatment, dyeing, printing, coating, finishing
Make-upcutting, sewing, assemblingMake-upcutting, sewing, assembling
TradeTrade
UseUse
DisposalDisposal
Fibre manufacturing: Natural fibres/Man-made fibres
Spinning of fibres Yarn manufacturing
weaving, knitting, non-woven technologiesCloth manufacturing
Finishing processespretreatment, dyeing, printing, coating, finishing
Make-upcutting, sewing, assembling
Trade
Use
Disposal
BREF Textile
Industry
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Environmental issues of textile finishing
Leaking Chemicals likely to enter the groundwater in a mixing station for chemicals (carpet factory in Egypt)
Ca. 7000 textile auxiliaries with approx. 400 – 600 single substances
Up to 300 m³ Water per ton finished textile
High chemical load of the waste water with non biodegradable auxiliaries
Energy consumption Air emissions Solid wastes Odours
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Environmental issues of textile finishingMain environmental loads from textile industry in Europe
Substances Environmental load (t/yr)
Salts 200 000 – 250 000
Natural fibres impurities (including biocides) and associated material (e.g. lignin, wax, etc.)
50 000 – 100 000
Sizing agents (mainly starch, starch derivatives, but also polyacrylates, polyvinylalcohol, carboxymethylcellulose and galactomannans)
80 000 – 100 000
Preparation agents (mainly mineral oils, but also ester oils) 25 000 – 30 000
Surfactants (dispersing agents, emulsifiers, detergents and wetting agents) 20 000 – 25 000
Carboxylic acids (mainly acetic acid) 15 000 – 20 000
Thickeners 5 000 – 10 000
Urea 5 000 – 10 000
Complexing agents <5 000
Organic solvents n.d.
Special auxiliaries with more or less ecotoxicological properties <5 000Source: Euratex
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Environmental issues of textile finishing Waste water in textile finishing mills
Up to 1 kg chemicals/kg textiles are used in textile finishing mills
More than 90 % of the organic chemicals and auxiliaries in pretreatment and dyeing operations does not stay on the fibre, but mainly ends up in the waste water
The wastewater load includes:• fibre by-products (e.g. fibre monomers like
caprolactam, fibre solvents and catalysts)• preparation agents applied in down-stream
processes• sizing agents applied in down-stream
weaving mills• non-fixed basic chemicals, textile auxiliaries,
and dyestuffs (including their by-products and impurities)
Process COD contentin mg O2/l
desizing 3.000 to 80.000
bleaching 3.000 to10.000
Scouring 2.000 bis 6.000
Exhausted dye liquoresreaktive dyeing
400 to 2.000
Exhausted dye liquoresdispersing dyes or vat dyes
5.000 to10.000
Residual dyeing liquors 10.000 to100.000
Residual finishing paddingbaths
5.000 to 200.000
Residual printing pastes 50.000 to 300.000
COD content of residual liquors of processes in the textile mill:
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
EXAMPLES FOR BAT
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Generic BAT for whole textile industry (I)Management und good housekeping
implementation of a monitoring system for process input and output precondition for identifying
priority areas and options for improving environmental performance
Input/output stream inventories can be drawn up on different levels (site level, process level)
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Generic BAT for whole textile industry (II)Management and good housekeeping
Equipment maintenance• Maintain machinery, pumps
and piping thoroughly and check for leaks
• Draw up maintenance plans that foresee regular maintenance and document all work activities
• Check and clean filters regularly
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Generic BAT for whole textile industry (III)Selection and use of chemicals
In general the overall strategy for the minimisation/optimisation of the chemicals used should consider the following steps:
1. where it is possible to achieve the desired process result without the use of chemicals, then avoid their use altogether
2. where this is not possible, select and use chemicals in a way that ensures the lowest overall risk.
Selection of auxiliaries and chemicals with a high degree of biodegradability/ bioeliminability, low human and ecological toxicity, low volatility and low smell intensity
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Cotton processing – recovery of sizing material
Sizing agents are the main source of COD in waste water
Water-soluble synthetic sizing agents such as polyvinyl alcohol, carboxymethyl cellulose and polyacrylates can be recovered by ultrafiltration
After ultrafiltration the concentrate can be re-used for sizing
The permeate can be recycled and re-used as water in the washing machine
Recycling of sizing agents is only technically and economically reasonable for integrated finishers with weaving and finishing near by
Recovery rates for sizing agents 80-85 %COD load is reduced by 40 – 70 %
BREF Textile Industry Chapter 4.5.1
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Cotton processing – Recover and re-use alkali from mercerising
Mercerising: main source of alkaline load of waste water
rinsing water from mercerising(weak lye: 40 - 50 g NaOH/l) is concentrated by evaporation for re-use in mercerisation.
Recycling degree up to 80%
alkaline load of waste water is reduced drastically
Pay-off time less than 1 year
Scheme of the caustic soda recovery process
BREF Textile Industry Chapter 4.5.7
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Process improvements for dyeing (I)Automated preparation and dispensing of chemicals
Microprocessor-controlled dosing systems meter chemicals automatically.
Usually the frequently used colourants (highest consumption) are selected for automation.
commonly applied in many companies in the textile industry (Examples of plants with production capacity ranging from 70 t/day to 5 t/day)
Benefits:• improved right-first-time perfomance minimising
corrective measures (e.g. reworks, redyes)• significant reduction of waste water pollution and
wasted chemicals thanks to the minimisation/ avoidance of liquor residues
BREF Textile Industry Chapter 4.1.3
Data from a textile dyehouse(production capacity 5500 t/year):17% reduction of reworks11% reduction of costs for chemicals10% reduction of costs for labour5 % increased dye machine efficiency
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Process improvements for dyeing (II)Carrier-free dyeing techniques or use of optimised carriers
Carriers include substances with human and aquatic toxicity, high volatility and high odour intensity (e.g chlorinated aromaticcompounds. o-phenylphenol, biphenyl and other aromatichydrocarbons, phthalates)
Carrier-free dyeing at high temperature using HT-dyeing equipment can be applied to all pure polyesters and wool-free PES blends
When dyeing polyester blends with fibres wich are sensitive to high temperatures (e.g.polyester/wool blends) chlorine-free carriers with improved toxicological and environmental characteristics can be used.
The optimised carriers are based on: • benzylbenzoate• aromatic carboxylic acid esters• N-alkylphthalimide.
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Process improvements for dyeing (III)Use of high-fixation polyfunctional reactive dyestuffs
Bifunctional (polyfunctional) reactive dyes offer very high levels of fixation in exhaust dyeing of cellulosic fibres
high reproducibility, low dependency on dyeing conditions and therefore right-first-time dyeing
Fixation rate is increased from 60 % to 80 % Reduction of waste water pollution (e.g. TDS)
Data for new dyes:90°C fixation temperature40 % reduction of water consumption40 % reduction of energy consumption30 % reduction of salt conumption
BREF Textile Industry Chapter 4.6.10
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Process improvements for dyeing (IV)Exhaust dyeing with low-salt reactive dyes
exhaust dyeing of cellulosic fibres with reactive dyestuffs requires usually 50 - 60 g salt/l (up to 100 g salt/l for dark shades)
Low-salt reactive dyes need only about two-thirds of this quantity
low-salt dyes can be kept in solution at a higher concentration use of low liquor ratio (L.R.) dyeing machines further reduction of salt consumption
low-salt reactive dyes are not combinable with other dyes, processing parameters have to be complied in an exact way
Winch (L.R. 1:20) Jet (L.R. 1:10) Low L.R. Jet (L.R. 1:5)
Traditional dyes (salt 60 g/l) 1200 kg 600 kg 300 kg
Low salt dyes (salt 40 g/l) 800 kg 400 kg 200 kg
Quantities of salt required for dyeing 1000 kg of fabric to a medium depth of shade BREF Textile Industry Chapter 4.6.11
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Process improvements for dyeing (V)Minimisation of dye liquor losses in pad dyeing techniques
Main emission sources in pad dyeing processes arise from the discharge of the residual dyeing liquor in the pad, pumps and pipes
Reduction of these losses can be achieved by• minimising the capacity of the dip trough (e.g. flex-
shaft, U-shaft)
• dosage of the padding liquor based on measurement of the pick-up reduction of liquor loss in the tanks from 150 litres to 5 – 15 litres
The use of a U‐trough reduces the bath residue by 60–90%.
BREF Textile Industry Chapter 4.6.7
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Measures for reduction of water consumption (I)Efficient washing processes
Replacement of overflow rinsing with “drain and fill rinsing” or “smart rinsing”.
Use of “Drain and fill” in combination with low liquor ratio machines equipped with time-saving devices (power draining and filling, combined cooling and rinsing, full volume heated tanks)
50 – 75 % less water consumption Water conservation in continuous washing and
rinsing:• Water flow control• countercurrent washing• Use of squeeze rollers or vacuum extractors
for the reduction of carry-over
Water consumption (l/kg)
Pretreatment process
Washing for desizing 3 ‐ 4
Washing after bleaching 4 ‐ 5
Washing to remove NaOHafter mercerisation
4 ‐ 5
Washing after dyeing
Reactive dyestuffs 10 ‐ 15
Vat dyestuffs 8 ‐ 12
Washing after printing
Reactive dyestuffs 15 ‐ 20
Vat dyestuffs 12 ‐ 16
BREF Textile Industry Chapter 4.9.1, 4.9.2
Achievable specific water consumption levels for continuous washing processes
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Measures for reduction of water consumption (II)Water re-use/recycling in batch dyeing processes
exhausted hot dye baths are analysed for residual colourant and auxiliary concentration, replenished and re-used to dye further batches
easiest systems for re-use are dye classes with high affinity (exhaustion) and mimimum changes during the dyeing process (e.g. acid dyes for nylon and wool, basic dyes for acrylic, direct dyes for cotton and disperse dyes for synthetic fibres)
on average four cycles of the same shade are possibleReduction of overall water consumption of 33 %Cost savings (depending on water price and effluent disposal
costs)
BREF Textile Industry Chapter 4.6.22
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Measures for reduction of energy consumption (I)General technical measures to increase energy efficiency
heat-insulation of pipes, valves, tanks, machines segregation of hot and cold waste water streams
prior to heat recovery and recovery of heat from the hot stream.
optimising boiler houses (re-use of condensed water, preheating of air supply, heat recovery in combustion gases)
installing frequency-controlled electric motors installing heat recovery systems on waste off-
gases energy savings up to 70% for heat recovery on waste gases on stenters
BREF Textile Industry Chapter 4.1.1
Increased insulation on the stenters alone from 120 mm to 150 mm saves 20 percent of energy
heat-insulation of pipes
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Measures for reduction of energy consumption (II)Control of energy consumption
Monitoring and control of energy consumption is an essential precondition for energy efficiency increase in companies
For monitoring consumption, indicators are defined for the entire company and for single processes e.g.
• energy consumption (gas, oil, etc.) per ton of steam produced
• electricity consumption of big aggregates per ton of product produced
• consumption of steam and electricity per processed goods or group of goods
• gas consumption for the stenter frame per group of goods
German textile plant:Cost savings of 175 000 €/a due to measures taken after monitoring/control of energy consumption.
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Measures for reduction of energy consumption (III)Energy recovery
Reuse of warm water by counterflow (e.g. washing of raw cotton, peroxide bleaching and alcalic boiling off, Dyeing, continuous washing and rinsing).
Use of warmed-up cooling water (e.g. from soda lye recovery, batch dyeing, water-cooled compressors) directly for warm processes like dyeing or rinsing.
Use of water/water heat exchanger for heating fresh water, e.g.:• Heat exchanger for waste water from reactive dyeing • Heat exchanger for waste water from washing and rinsing
Use of air/water or air/air heat exchange, e.g.:• Heat exchanger for waste gas from stenters for pre-heating of air
introduced into the stenter• Heat exchanger for cooling air of compressors for pre-heating of
process water or heating water
The use of heat content of rinsing water from continous washing for heating of fresh water leads to energy savings of approx. 75% .
The heat exchange from waste water of a pad‐steam dyeing to the water for the washing section saved yearly 1600 MWh natural gas.
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Measures for reduction of energy consumption (IV)Minimisation of energy consumption of stenter frames
Reduction of moisture content of the fabric with vacuum extraction systems, squeezing rollers etc. before it enters the stenter
Energy saving of up to 15% Regular maintenance of the burners Use of optimised nozzles and air guidance systems (e.g. nozzle
systems that can be adjusted to the width of the fabric) Optimisation of air flow at the stenters (exhaust humidity between 0.1
and 0.15 kg water/kg dry air)Energy saving of up to 57%
installation of heat recovery systems Energy saving of up to 70%
insulation of thermal treatment units Energy saving of up to 20% BREF Textile Industry Chapter 4.8.1
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Waste water treatment (I)General principles for waste water management and treatment
Characterizing the different waste water streams arising from the process Segregate the effluents at source
according to their contaminant type and load
• To ensure that a treatment facility receives only those pollutants it can cope with
• To enable the application of recycling or re-use options for the effluent
3-way valve for segregation of effluents
Segregated effluentsdestined fordifferent treatments
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Waste water treatment (II)General principles for waste water management and treatment Do not send any waste water into the biological treatment facility that could cause
malfunctions there. Employ alternative cleaning techniques for waste water with relevant volumes of non-
biodegradable substances:• chemical oxidation for highly-polluted, selected, non-biodegradable waste water partial
flows (e.g. desizing baths)• Precipitation and flocculation for partial flows containing heavy metals• membrane process for heavily coloured waste water partial flows and waste water with a
high volume of dissolved substances If waste water with non-biodegradable compounds is not treated separately, then additional
physical-chemical treatment of the waste water as a whole is required. Specific process residue (e.g. printing paste residue, padding liquor residue) should not
enter the waste water but be disposed of in a more appropriate manner.
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Waste water treatment (III)Pretreatment
Case example: De-colouring using membrane technology
Company finishes knitted fabric Pretreatment of waste water from pad batch
dyeing and from continuous washers 1. step: nanofiltration
• Efficiency of de-colouration: 80 - > 99%
2. step: electrochemical de-colouration• Efficiency of de-colouration:
35 – 78% Aftertreteatment in municipal waste water
treatment plant
1. step: nanofiltration
2. step: electrochemical de-colouration
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Case example: Anaerobic pretreatment of desizing effluents
Company finishes woven, knitted and non-woven fabric
1. buffering/pre-acidification 2. anaerobic treatment in fixed bed
reactor COD-removal efficiency:
60 – 70 % Aftertreatment in municipal waste
water treatment plantleft side: two Buffer tanks, right siede: fixed bed reactor
Waste water treatment (IV)Pretreatment
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Waste water treatment (V)Treatment of mixed effluent
Case example A: Treatment of mixed effluent in activated sludge system effluent from one textile finishing mill is treated
company mainly finishes cotton fabric
about 5 % of the treated waste water is recycled for washing and cleaning operations (floor washing, cleaning of printing equipment such as pumps, pipes, squeegees and screens)
decolourisation is achieved through reductive cleavage of azo groups of dyestuffs by an iron(II)-salt
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Influent Effluent
pH 9 – 9.5 7.8 – 8.6
COD[mg O2/l]
1200 – 1500 90 – 110
BOD5
[mg O2/l]400 - 500 < 5
NH4-N[mg N/l]
11 - 25 0.3 – 1.6
N-org[mg N/l]
30 - 40 5 - 10
Ptotal
[mg P/l]10 - 25 1 – 2.5
Scheme of the treatment of mixedeffluent in activated sludge system
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Waste water treatment (VI)Treatment of mixed effluent
Case example B: Combined treatment of textile waste water with municipal waste water effluent from about 30 textile finishing units is treated together with
municipal waste water textile waste water accounts for about 30 % of the hydraulic load and for
about 40 % of the COD the textile finishing industries discharge their waste water to the public
sewer after neutralisation on site various companies have pretreatment plants, especially pigment printing
units, which treat the waste water from cleaning the printing equipment by flocculation/precipitation
layout of the plant is typical with bar screen, aerated grit and grease chamber, primary clarifier, denitrification and nitrification stage
Specific characteristc: presence of an additional treatment with activated carbon powder in order to minimise COD and colour in the final effluent
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Bar screenInfluent
Aerated grit andgrease chamber
Primary clarifier(sedimentation)
De-nitrification
Activated sludge(nitrification)
Secondary clarifier
Returnsludge
Primary sludge
Excesssludge
Thickener
Anaerobicdigesters
Anaerobicallystabilised sludge,including activatedcarbon to securedmunicipal landfill
Chamberfilter press
Filtrate and overflow of anaerobic digesters
MixerActivated carbonpowder
Contact andequalisation tank
Pumpingstation
ClarifierScrew pumpSand filters
Dischargeto river
Polyelectrolyteand alum sulphate
BackwashWater containingActivated carbon
Influent Effluent
pH 6.8 – 7.5
COD [mg O2/l] 278 11
BOD5 [mg O2/l] 138 3
NH4-N [mg N/l] 12.5 0.4
Ptotal [mg P/l] 3.7 0.15Combined treatment of textile waste water withmunicipal waste water
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Waste Management
processes should be designed and operated to prevent, or minimize, the quantities of wastes generated
separate collection of unavoidable solid waste
minimize hazardous waste generation by implementing stringent waste segregation to prevent the contamination of non-hazardous with hazardous waste
reduction of packaging use of returnable containers
returnable containers
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Air emission abatement techniques
Different textile processes demand different off-gas abatement Case to case studies for the choice of the abatement technique is
necessary The following techniques are used separately or in combination:
• oxidation techniques (thermal incineration, catalytic incineration)
• condensation techniques (e.g. heat exchangers)• absorption techniques (e.g. wet scrubbers)• particulates separation techniques (e.g. electrostatic
precipitators, cyclones, fabric filters)• adsorption techniques (e.g. activated carbon adsorption)
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Environmental standards in the textile and shoe sector
Guideline on the basis of the BREFs
Developed in cooperation with brands, retailers and civic institutions
Objectives:• Facilitate the access to the BREFs
• Enter into a practical dialogue along the supply chain
http://www.umweltbundesamt.de/uba-info-medien-e/4128.html
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Conclusions (I)
The Textile BREF is a valuable source of information on available techniques, their applicability and their associated consumption and emission levels.
BAT is more than the application of specific technologies; good housekeeping, maintenance, input control and a proper monitoring system for the emissions are also relevant
As the structure/environmental problems of the European Textile industry is different, the BREF does not provide detailed BAT conclusions for all emissions relevant in India (e.g. TDS), but at least it gives some indication.
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Conclusions (II)
We encourage you to benefit from the information provided in the Textile BREF
Where processes currently applied in India are not covered in the BREF, it might be beneficial to initiate an information exchange process on BAT in your country, based on the same principles as under the IED.
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Thank you for your attention!
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Useful links
BREF Textile Industry:http://eippcb.jrc.ec.europa.eu/reference/txt.html
Environmental standards in the textile and shoe sector:http://www.umweltbundesamt.de/publikationen/environmental-standards-in-textile-shoe-sector
Checklists based on BAT in the textile industry:http://www.umweltbundesamt.de/publikationen/checklist-based-on-best-available-techniques-in
Cleaner production Germany:http://www.cleaner-production.de/en.html
Blue Angel for textiles:http://www.blauer-engel.de/en/products_brands/search_products/produkttyp.php?id=573
Carbon Performance Improvement Initiativehttp://www.cpi2.org/home/
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
When carbon dioxide is heated to above 31°C and pressurized to above 74 bars, it becomes “supercritical” high (liquid-like) density that enables dissolution of compounds and the low viscosity that enables good penetration
For dyeing of textile the carbon dioxide is heated to 120°C and pressurized to 250 bars
During dyeing of polymer fibres, CO2 loaded with dyestuff penetrates deep into the polymer structure of the fibres and thus provides effective coloration of these materials
Benefits: no water consumption – and therefore no wastewater no off-gas emission (90-95% of the CO2 can be recycled) no drying step after dyeing no leveling and dispersing agents dyestuff residues can be recycled
Process improvements for dyeing Dyeing in supercritical carbon dioxide
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Waste water treatment (III)Composition of total waste water stream prior treatment
Parameter Concentration in total wastewater stream
pH-value 5 - 13
COD 400 - 5000 mg O2/l
BOD5 80 – 1500 mg O2/l
AOX 0.05 – 1 mg Cl/l
NH4-N < 0.1 – 120 mg N/l*
HC < 0.1 – 110 mg/l**
Anionic tensides 2 – 24 mg/l
Nonionic tensides 5 – 50 mg/l
Cu < 0.001 – 0.5 mg/l
Zn 0.02 – 1.1 mg /l
Cr < 0.005 – 0.2 mg /l
Data from 50 textile finishing mills in Germany
* high values for vat printing and reactive printing where relevant amount of urea is used
** high values from pretreatment of polyester or polyamide (washed out preparations)
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“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Waste water treatment (IX)Treatment of mixed effluent
Case example C: Treatment of mixed waste water with about 60 % water recycling Company finishes cotton knitted fabric and dyes with reactive
dyestuffs Before treatment, the hot streams (> 40°C) are submitted to heat
recovery The following steps are then carried out on the mixed effluent:
• equalisation (about 20 h equalisation) and neutralisation• activated sludge treatment in a special system consisting of loop
reactors and clarifiers • adsorption stage• flocculation/precipitation and removal of the sludge by flotation• filtration in a fixed bed gravel filter
about one third of the flow is discharged to the river two-thirds are treated in an activated carbon filter and desalinated in a
reverse osmosis plant
48
“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Influent Effluent* Recycelt stream**
pH 7.3 7.2 7.0
COD[mg O2/l]
515 20 10
BOD5
[mg O2/l]140 < 0.1 < 0.1
AOX[mg Cl/l]
0.56 0.2
Treatment of mixed waste water with about 60 % water recycling
* After filtration, before absorption
** after reverse osmosis
49
“BAT in textile and pulp and paper sector” – 18th – 29th November 2013 B. Zietlow, Umweltbundesamt
Air emission abatement techniques (II)Examples of hazardous substances in waste air
Substance Possible sourceAcrylonitrile Polymer dispersionsAcrylamide Reactive polymers, flame-retardantsAcrylates (methyl, ethyl, butyl)
Coating agents and binders for non-wovens
Benzylalcohol Carriers
Caprolactam Polyamide 6 powder/textiles
Diethylenetriamine SoftenersDiphenylmethane-2,4 diisocyanate
Extender, polyurethanes
Hexamethylendiamine PolycondensationproductsOxalic acid Bleaching auxiliaryVinylacetate Polyvinylacetate
•Signifacantemissions occur at drying processes
•Emissions are from the fibres and from preparations and finishing chemicals