Cleaner production in Romanian textile industry: a case study

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  • This article was downloaded by: [Uppsala universitetsbibliotek]On: 09 October 2014, At: 19:08Publisher: RoutledgeInforma Ltd Registered in England and Wales Registered Number: 1072954 Registeredoffice: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK

    International Journal of EnvironmentalStudiesPublication details, including instructions for authors andsubscription information:http://www.tandfonline.com/loi/genv20

    Cleaner production in Romanian textileindustry: a case studyIuliana Dumitrescu a , Ana Maria Mocioiu a & Emilia Visileanu aa The National R&D Institute for Textile and Leather , LucretiuPatrascanu 16, Bucharest, RomaniaPublished online: 11 Aug 2008.

    To cite this article: Iuliana Dumitrescu , Ana Maria Mocioiu & Emilia Visileanu (2008) Cleanerproduction in Romanian textile industry: a case study, International Journal of EnvironmentalStudies, 65:4, 549-562, DOI: 10.1080/00207230802263610

    To link to this article: http://dx.doi.org/10.1080/00207230802263610

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  • International Journal of Environmental Studies,Vol. 65, No. 4, August 2008, 549562

    International Journal of Environmental StudiesISSN 0020-7233 print: ISSN 1029-0400 online 2008 Taylor & Francis

    http://www.tandf.co.uk/journalsDOI: 10.1080/00207230802263610

    Cleaner production in Romanian textile industry: a case study

    IULIANA DUMITRESCU*, ANA MARIA MOCIOIU AND EMILIA VISILEANU

    The National R&D Institute for Textile and Leather, Lucretiu Patrascanu 16, Bucharest, RomaniaTaylor and FrancisGENV_A_326528.sgm

    (Received 11 June 2008)10.1080/00207230802263610International Journal of Environmental Studies0020-7233 (print)/1029-0400 (online)Original Article2008Taylor & Francis0000000002008IulianaDumitrescuiuliana.dumitrescu@gmail.com

    This paper reports the changes resulting from adopting environmentally sensitive criteria in NovatextilePitesti, Romania. The changes have improved the operation of the production plant and reduced costsat the same time.

    Keywords: Cleaner production; Yarns; Pre-treatment

    1. Introduction

    Rising costs to the environment and to the business sector have forced companies to seekclean, eco-friendly technologies. A clean production technology requires the implementationof an environmental preventive strategy, integrated and distributed through processes, prod-ucts and services. This approach increases the process efficiency and decreases the environ-mental risks.

    Some of the benefits of implementing a cleaner production are: the reduction of raw mate-rials used in the process, reduction of production costs, removal of dangerous raw materials,reduction of quantity and toxicity of wastes, the improvement of the overall quality of theproducts and processes [1].

    In Romania the issue of clean process implementation has become more urgent followingentry to the EU. Companies that do not follow the European law on the prevention of integralcontrol of pollution (Directive 96/61/CE) and have not secured the integral medium permit,risk closure.

    Many Romanian textile enterprises (Dacia Textile, Vastex, Carpatex, Zefir and Pobac), inorder to prevent collapse while meeting the excessively high costs of replacing the old tech-nologies and equipment (during 19601975), when the worst problems of pollution appeared,involved themselves in projects of international collaboration, taking advantage of massiveinvestment in clean technologies.

    Dacia Textile, as part of the Danish Romanian bilateral project Cleaner Technologies inthe Romanian textile industry, completely replaced the fabric preparation section, the one with

    *Corresponding author. Email: iuliana.dumitrescu@gmail.com

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  • 550 I. Dumitrescu et al.

    the highest degree of pollution. The total investment (EUR 913,000) of the complete line forcold pre-treatment, including an impregnation compartment with a dosing system for the addi-tion of chemicals, a dispenser and a reaction station, a washing line and a drying line wassupported by the Danish Government EUR 427,726 and Textila Dacia EUR 485,274 [2].

    Besides, the Dutch Ministry of Economic Affairs (The Project Sustainable Rehabilitationof the Print Technology at Textila Dacia), financially supported Textila Dacia to implementmodern print technology, by which the pigment discharging into water was drasticallyreduced, and the printing paste and energy and water consumption were diminished [3]. Manyenterprises, have tried, with their own resources, to reduce pollution and improve productivity.

    Such an enterprise is NOVA TEXTILE, Pitesti, Romania, which introduced the clean tech-nology of 100% cotton yarns pretreating-dyeing.

    2. The implementing of the clean technology of 100% cotton yarns pretreating-dyeing

    2.1. The reason for change

    NOVA TEXTILE produces cotton and cotton type yarns and fabrics, and is structured asfollows:

    spinning, which produces 1960t/year carded and combed yarns; weaving, which has the capacity of 10,000,000 m2/year cotton and cotton type woven

    fabrics; finishing (boiling-bleaching; dyeing, printing, sizing) with a capacity of 12,000,000 m2/year; clothing (interior decorations, coverings, furniture cushions, bed linen, working and

    protection equipment; padded products) 220,000 pieces/year.

    The high consumption levels for raw material, water, natural gas, electricity, the costs ofpollution, and the low profit made it necessary to increase efficiency and reduce pollution.The wet pretreating-dyeing of the yarns was the first process to be improved. This process,essential for a high textile material quality, is among the biggest consumers of raw materialsand utilities, responsible for 1025% of the effluent [46].

    Any impurity left on the material interfered with the subsequent processes of dyeing andfinishing. Big quantities of chemical auxiliaries and water are used to remove these (yarns,fats, waxes, pectin, etc.), during the conventional cleaning processes. All the impuritiesremoved from the yarns, as well as over 90% of the chemical auxiliaries (sodium hydroxide,surfactants, sodium silicate, carbonate, etc.) are to be found in the waste waters.

    During the bleaching process, the hydrogen peroxide, which is used in large quantities toensure high quality whiteness, may lead to degrading and increasing the hydrolysis of the reactivedyes. The peroxide residues also have a negative influence. The residues from the bleachingbaths have to be removed from the material and the equipment before adding the dyestuff. Asa rule, the successive washing of the material with water diminishes the concentration of theresidual bleaching agent and improves dyeing.

    This implies the use of a very large volume of water during the reducing, cold and hotwashing stages, a longer processing time or the use of certain chemical products that are toxicto the environment and lead to high costs and a bigger quantity of waste water.

    To overcome these problems (water pollution, high consumption levels for electricity,steam, water, etc.), improvements to the cotton yarn pretreating-dyeing technological processwere proposed.

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  • Cleaner production in Romanian textile industry 551

    2.1.1. The improving of the cotton yarn pretreating-dyeing technological process. Theold cotton yarn pretreating-dyeing technological process comprises the stages of yarnpreparation. The spools (400 pieces 200 yarn kilos), placed on a creel, are introduced intoa 3000 l capacity Thies dyeing apparatus where the cleaning-bleaching process takes place.Within the same container, the reducing, hot and cold washing processes also take place,being followed by dyeing with reactive dyes. After dyeing, the fabric washing is done onthe same apparatus, the washing waters being discharged in 30 minutes. Finally, the dyedyarns are softened and steam dried. The spool creel stays in the drying container for aboutthree hours.

    The clean technological process contains the same stages as the previous one, but nowthe cleaning-bleaching stage is done with chemical auxiliaries having a high efficiency and aminimum impact on the environment; and the stages of reducing, cold and hot washing havebeen replaced by the neutralizing stage.

    During the cleaning-bleaching stage, the following auxiliaries have been replaced:

    The T Auxiliary (a surfactant with a relatively low wetting power) was replaced bySandoclean JSF which has these advantages: it is a good wetting, emulsifying, dispersingand low foaming agent; it can be used as a detergent for all fibre types; it is biodegradable,it does not contain APEO and nitrogen, phosphorus, silicone compounds.

    The sequestering agent (Heptol ESW a phosphoric one with eutrophication effects whendischarged) was replaced by Sirrix SB, which is a pH regulator for the processes ofbleaching with hydrogen peroxide. Sirrix SB ensures a quicker and more economicprocess as compared to the conventional bleaching processes; it gives advanced hydrophi-licity to the textile material, a high quality whiteness; it does not need rinsing after bleach-ing, and so water is saved; it reduces the treating time, leading thus to more profitable useof equipment; it is biodegradable and does not contain APEO and compounds based onphosphorus and nitrogen.

    In the new process, the reducing, cold and hot washing stages have been replaced by only oneneutralizing stage. Thus, the water consumption is substantially reduced. The water and,simultaneously, energy, time and manual labour component were all reduced, owing to theuse of the catalyses (BACTOSOL ARL was used in our process). BACTOSOL ARL [7] is abiocatalyst used to decompose the hydrogen peroxide into water and oxygen, without degrad-ing the substrate or the dyes.

    The efficient and precise adjusting of the pH of the enzyme containing (Bactosol ARL)bath is effected with the help of the neutralizing liquid agent Sirrix NE. It is biodegradableand does not contain APEO and compounds based on phosphorus and nitrogen.

    Moreover, in order to make efficient the whole activity of the enterprise and to ensureclean, non-polluting technological processes, the thermal power station was modernized.New boilers replaced the old. The new boilers, equipped with automatic measuring apparatus(flow meter), allowed proper monitoring of gas consumption.

    Important reductions in consumption of the thermal energy and natural gas, at the level ofthe whole enterprise, as well as low CO2 emissions have thus been obtained.

    2.2. The benefits of implementing the cleaner technology

    By implementing the changes, it was possible to reduce: the quantities of chemical auxiliariesused to prepare the material; the electric and heat energy; the operating time and manual

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  • 552 I. Dumitrescu et al.

    labour component; the effluent costs; the water and air pollution. There was also a saving inclean water. The quantifying of the results was done by:

    effecting the raw material and electric and heat energy balances; quantifying the quality indicators of the waste water coming from all the technological

    process steps; analysing the characteristics of the yarns obtained by the two processes; calculating the economic effects as a consequence of the changes.

    3. Results and discussions

    3.1. Material balance

    The stages and the chemical auxiliaries used in both technological processes are presented intable 1. In order to demonstrate the economic effects of the new process, only the stages thatare different in the case of the two processes were taken into account, that is the cleaningbleaching and the reducing/cold/hot washing ones, for the initial process and the cleaning-bleaching and neutralizing ones for the optimized (cleaner) process (table 2).

    Table 2 shows that, in the new process:

    the Sandoclean JSF quantity is 3 times smaller than the Auxiliary T one (4.8 kgs of AuxiliaryT versus 1.6. kgs of Sandoclean JSF);

    Sirrix SB leads to water savings of at least 1/3 as compared to the conventional procedure; reductions of specific chemical auxiliary consumption 0.1315 kg/kg of yarns and 28 L

    water/kg of yarns can be obtained.

    By introducing minimum measures (the replacing of the reducing/cold/hot washing processesby one neutralizing stage; the use of chemical auxiliaries with a high efficiency and a lowpolluting effect) it is possible to obtain a reduction by 73% of the chemical auxiliaryconsumption and by 50% of the water consumption.

    3.2. The general energy balance for the cotton yarn preparing process

    The reducing of the thermal requirement was done by:

    1) replacing the old measuring apparatus (gas flow meter-type recorder) with counter-typemodern measuring apparatus. Such an initiative by itself does not lead to improving thecombustion function, but it permits the accurate monitoring of fuel consumption. Thischange had an extremely favourable economic effect. The old gas flow meter gave bigerrors and the consumption invoiced by the supplier (and paid by the enterprise) was byalmost 30% higher than the correctly measured consumption.

    2) Replacing old boilers with modern, automated ones of 10 t saturated steam/h, under apressure of 8 bar and a yield of 92%. It is notable that in the initial configuration, whichcomprised three old boilers; only two boilers were permanently in function. Thepronounced physical wear of the boilers did not allow an increase of their loading bymore than 50% of the nominal capacity. The third boiler was reserved for use only whenone of the two boilers was out of action.

    Each boiler had a delivery rate of 10t/h and a declared natural gas consumption of720 Nm3/h. Measurement of their operational performance led to the conclusion that theiryields oscillated between 43.2% and 74%, depending on the loading degree.

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  • Cleaner production in Romanian textile industry 553

    Tabl

    e 1.

    The

    sta

    ges

    and

    chem

    ical

    aux

    iliar

    ies

    used

    in th

    e in

    itial

    and

    cl

    eane

    r p

    roce

    sses

    Initi

    al p

    roce

    ssC

    lean

    er p

    roce

    ss

    Che

    mic

    al a

    uxili

    arie

    sPr

    oces

    s st

    ages

    Proc

    ess

    stag

    esC

    hem

    ical

    aux

    iliar

    ies

    Wat

    er: 2

    800L

    1. C

    lean

    ing-

    blea

    chin

    gt

    = 9

    5C

    t = 3

    0 m

    in

    1. C

    lean

    ing-

    blea

    chin

    gt

    = 9

    5C

    t = 3

    0 m

    in

    Wat

    er: 2

    800L

    Sequ

    este

    ring

    age

    nt (

    Hep

    tol E

    SW):

    4.8

    kg

    Sirr

    ix S

    B (

    blea

    chin

    g re

    gula

    tor)

    : 1.6

    0 kg

    Hyd

    roge

    n pe

    roxi

    de: 4

    .8 k

    g2%

    Hyd

    roge

    n pe

    roxi

    de: 4

    .00

    kgA

    uxili

    ary

    T (

    wet

    ting

    agen

    t): 4

    .8 k

    g1.

    60 k

    g Sa

    ndoc

    lean

    JSF

    (w

    ettin

    g ag

    ent)

    Sodi

    um h

    ydro

    xide

    : 16

    kgSo

    dium

    hyd

    roxi

    de:

    4.00

    kg

    Wat

    er: 3

    280

    0LH

    ydro

    sulf

    ite: 5

    .6 k

    g2.

    Red

    ucin

    g/co

    ld-h

    ot w

    ashi

    ng2.

    Neu

    tral

    izin

    gt

    = 6

    0C

    pH =

    7t:

    15 m

    in

    Sirr

    ix N

    E :

    0.90

    kg

    Wat

    er: 2

    800L

    Bac

    toso

    l AR

    L: 1

    .20

    kg

    3% A

    mbi

    fix

    oran

    ge H

    E-2

    R: 7

    .60

    kg3%

    Am

    bifi

    x re

    d H

    E-7

    B: 6

    .00

    kg3.

    Dye

    ing

    t =

    80

    Ct =

    2.5

    hou

    rs

    3. D

    yein

    gt

    = 8

    0C

    t = 2

    .5 h

    ours

    3% A

    mbi

    fix

    oran

    ge H

    E-2

    R: 7

    .60

    kg3%

    Am

    bifi

    x re

    d H

    E-7

    B: 6

    .00

    kg

    70g/

    L S

    odiu

    m c

    hlor

    ide:

    196

    kg

    70g/

    L S

    odiu

    m c

    hlor

    ide:

    196

    kg

    20g/

    L S

    odiu

    m c

    arbo

    nate

    : 56

    kg

    20g/

    L S

    odiu

    m c

    arbo

    nate

    : 56

    kgW

    ater

    : 2

    280

    0L4.

    Col

    d/ho

    t was

    hing

    4. C

    old/

    hot w

    ashi

    ngW

    ater

    : 2

    280

    0LW

    ater

    : 280

    0L; 2

    % A

    cetic

    aci

    d: 2

    ,8 k

    g5.

    Neu

    tral

    izin

    g5.

    Neu

    tral

    izin

    gt =

    10

    min

    t =

    40

    C

    Wat

    er: 2

    800L

    ; 2%

    Ace

    tic a

    cid:

    2.8

    kg

    Wat

    er: 2

    800L

    ; Sur

    fact

    ant:

    2.8

    kg6.

    Soa

    ping

    6. S

    oapi

    ngW

    ater

    : 280

    0L; S

    urfa

    ctan

    t: 2.

    8 kg

    sW

    ater

    : 280

    0L7.

    Hot

    /col

    d/co

    ld w

    ashi

    ngs

    7. H

    ot/c

    old/

    cold

    was

    hing

    sW

    ater

    : 280

    0LW

    ater

    : 280

    0L; 3

    % S

    evof

    ix: 6

    kg

    8. R

    etre

    atin

    g8.

    Ret

    reat

    ing

    Wat

    er: 2

    800L

    ; 3%

    Sev

    ofix

    : 6 k

    gW

    ater

    : 280

    0L9.

    Sof

    teni

    ng9.

    Sof

    teni

    ngt =

    10

    min

    t =

    30C

    Wat

    er: 2

    800L

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  • 554 I. Dumitrescu et al.

    At present, after modernization, work is done in a normal regime with only one boilerwhich can be effectively filled in at 10 t steam/h, the second one being kept as reserve. Thechanging of the boilers was justified by the savings through reducing the natural gasconsumption, the savings being 26,762 Euro/month, which pays back the investment in oneyear. Appendix 1 presents the calculation of the heat energy consumption.

    3.2.1. The specific thermal energy consumption. The data taken from the companysrecords show a total steam consumption of 767.4 kgs for 200 kgs of yarns, in the case ofusing the old boilers, and 596 kgs of steam in the case of using the new boilers. Calcula-tions show that in the case of the initial process there was a specific steam consumption of3.84 kgs of steam/kg yarns and a specific heat energy consumption of 9.62 MJ/kg of yarns,and, in the case of the optimized process, a specific heat energy consumption of 7.47 MJ/kg of yarns. Thus, by introducing the new technological process, the company obtainsspecific heat energy savings of 2.15 MJ/kg of yarns that is 430 MJ for the processed batchof 200 kgs.

    If the carded yarn production of 1960 t/year is considered, without taking into account the12,000,000 m2/year that result from the finishing department, the heat energy savings wouldachieve a value of 4,214,000 MJ/year.

    3.2.2. The methane gas consumption. The specific natural gas consumption in the thermalpower station was of 0.432 Nm3/kg of yarns in the case of the old boilers with a yield of 64%,and of 0.234 Nm3/kg of yarns, for the improved technological process, in which new boilersare used, with a yield of 92%. In this case, the methane savings for 1 kg of yarns is of 0.198Nm3, that is, savings of 45.84% are obtained as compared to the initial thermal energy andfuel consumption.

    Use of the new boilers has benefited the environment, too. Thus, according to the projectdata, by increasing the boiler output, one can achieve hourly natural gas savings of 211 Nm3

    for one boiler.Considering that the work in the factory is carried out in three shifts, 250 days in one year,

    the CO2 emission reduction is of 2500 t/year.

    Table 2. The specific material consumptions for the initial and the cleaner processes

    No. Indicator M.U. Initial process Cleaner process

    Resource consumption

    1. Cotton yarn specific consumption: kg/kg 1 1

    2. Chemical auxiliary specific consumption

    Sequestering agent (Heptol ESW) kg/kg 0.024 Sirrix SB: 0.008

    Hydrogen peroxide kg/kg 0.024 0.02

    Wetting agent kg/kg Auxiliary T: 0.024 Sandoclean JSF: 0.008

    Sodium hydroxide kg/kg 0.08 0.002

    Enzymes kg/kg Bactosol ARL: 0.006

    Hydrosulphite kg/kg 0.028 Sirrix NE: 0.0045

    Total chemical auxiliary specific consumption kg/kg 0.180 kg/kg yarns 0.0485 kg/kg yarns

    3. Total water specific consumption L/kg 56 28

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  • Cleaner production in Romanian textile industry 555

    No air polluting emissions were taken into consideration (sulphur oxides, nitrogen oxides,powders) as, in burning the methane gas in boilers of this type, such emissions cannot be found.

    In summary, the optimized process provided significant savings in the thermal energy andsteam consumption (table 3). Note the electric energy quantities were calculated on the basisof the enterprise invoices and taking into account the characteristics of the installations usedin the process.

    3.3. The environment performances water pollution

    The quantities of impurities existing in the discharged waste water volumes, by stages and bytotal yarn pretreating-dyeing process effected with reactive dyes, are indicated in tables 46.

    The initial process of cotton yarn preparing and dyeing produces highly polluted wastewaters evacuated in boiling and after dyeing.

    The exhausted dye bath is polluted through the oxidizing substances owing to the presenceof the sulphites resulted from oxidizing the sodium hydrosulphite and which becomesulphates. The waste waters resulting from the soaping stage have high CCO-Cr valuesowing to the presence of the detergent. The neutralizing waste waters, intermediate washingsand final washings contain relatively low pollution.

    The exceeding of permitted limits by the main pollution indicators, especially in the clean-ing-bleaching process required the improvement of this process; quality indicators for thewaste waters are presented in table 5.

    By comparing the parameters for the two processes (table 6), one can see that, by usingcertain efficient chemical auxiliaries, almost all the quality indicators for the waste watersshow a significant improvement since the changes, and now range between the limits set by

    Table 3. The specific energy and steam consumption

    Thermal energy/gas consumption Initial process Cleaner process Savings (%)

    Specific steam consumption 3.84 kgs/kg 2.98 kgs/kg 22.4Thermal energy consumption 9.62 MJ/kg yarns 7.47 MJ/kg yarns 22.34Specific natural gas consumption 0.432 Nm3/kg yarns 0.234 Nm3/kg yarns 45.84Electric energy 0.3KWh/kg 0.193KWh/kg 35.7

    Table 4. The quality indicators of the waste waters the initial process

    No. crt Operation pHCCO-Cr

    (mg O2/L)CBO5

    (mg O2/L)Residue(mg/L)

    Total suspensions (mg/L)

    Detergent (mg/L)

    1 Cleaningbleaching 1112 6440 686 3444 73 2 Washing 7.5 347 34 344 34 3 Dyeing 11 9273 761 36,237 7095 4 Washing 8.0 274 1008 45 5 Washing 7.5 313 414 22 6 Soaping 8.0 2472 14 1036 509 3007 Washing 7.5 215 459 17 358 Limit values admitted

    according to NTPA 002/20026.58.5 500 300 350 200 25

    9 Standard SR ISO 10523-97

    SR ISO 6060-96

    SR ISO 5815-98

    STAS 6953-81

    SR ISO 7875/1.2-96

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  • 556 I. Dumitrescu et al.

    NTPA 002/2002 Standard regarding the conditions for the wastewater discharge into the citysewage or directly into the water cleaning plant [8].

    The effluent pH is, in the old, unchanged system, around the value of 1011 owing to thebig NaOH quantities. At the same time with the soda quantity diminishing, the pH decreasessignificantly.

    The most important improvement can be seen in the case of the oxygen chemicalconsumption, the value for which is reduced from 6440 to 540 mg O2/l.

    The oxygen CBO5 biochemical consumption reaches half of the initial value, a fact thatdemonstrates a good biodegradability of the chemical compounds discharged into water.

    The bigger residue quantity resulting from the optimized process can be explained by abetter cleaning of the textile material.

    As shown in the tables 4 and 5, the waste water parameters depend on numerous factors,such as the process type, the stages of each process, the chemical auxiliaries used, the natureand quality of the textile material, the treating time and temperature.

    The data range obtained within the specific limits [6] of the cotton finishing processes maybe seen in table 7.

    3.4. The yarn physical-mechanical parameters

    Besides reducing the environment pollution, an essential objective of the business is theproduction of quality goods, to ensure their continued success in the market. The characteris-tics of the yarns obtained by the old process and by the optimized one are given in tables 8and 9.

    Table 5. The waste water quality indicators the cleaner process

    Test pH CBO5(mgO2/L) CCO-Cr(mgO2/L)Suspended

    solids (mg/L)Sulfate (mg/L)

    Deter-gents (mg/L)

    Fixed solids (mg/L)

    Cleaning-bleaching 10.2 301.0 540.28 10 85.0 19.10 4260Neutralizing 6.68 99.6 178.75 9 105.8 9.5 2110Dyeing 10.77 303.23 544.26 12 96.09 1.08 5810Neutralizing with acetic acid

    6.01 39.8 71.48 11 96.15 0.95 4650

    Soaping 6.69 68.6 123.14 10 85.0 8.12 1450Retreating 3% Sevofix 7.01 57.55 103.30 16 110.12 0.58 1813Softening 1% Softenol 7.6 219.11 393.28 20 85.70 11.2 5580Final collector from yarns dyeing with reactive dyes

    7.6 201.9 275.8 11 92.9 5.7 2100

    Limit values admitted according to NTPA 002/2002

    6.58.5 300 500 350 600 25

    Standard SR ISO 10523-97

    SR ISO 5815-98

    SR ISO6060-96

    STAS6953-81

    STAS 8601-70

    SR ISO 7875/1.2-96

    Table 6. The quality indicators of the waste waters resulted from the cleaning-bleaching process

    Parameter pHCCO-Cr

    [mg O2/L]CBO5

    [mg O2/L]Total suspensions,

    [mg/L]Residue [mg/L]

    Process initial 1112 6440 686 73 3444improved 10.2 540.28 301.0 10 4260

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  • Cleaner production in Romanian textile industry 557

    Remarks. As shown in table 8, the yarns present a practically identical count; the breakforce and elongation are lower owing to a more intense yarn cleaning; the Uster imperfec-tions are higher owing to the milder cleaning process. The yarn dyeing resistances (table 9)are practically identical in both processes.

    It can be said that the new, modified process, ensures almost the same characteristics asthose in the old one, the quality of yarns meeting market requirements.

    3.5. Financial effects

    The economic effects of the modifications have been striking. The consumption of water andenergy has been reduced drastically in the cleaner process. There has been a saving of about50% in water consumption and of about 3543% in energy (electricity and heat).

    4. Conclusion

    Wastewater problems (high pollution load, effluent taxes) and cost reduction have been themost important driving forces to implement cleaner production. There have been two broadareas of benefit.

    Table 7. The average concentration and specific load for the main cotton finishing operations

    Process pH CBO5 [mg O2/L] Total suspensions, [mg/L]

    Cleaning 1013 502900 760017,000Bleaching 8.59.6 01700 230014,000Dyeing 510 111800 50014,000

    Table 8. The yarn quality indicators

    Yarns dyed according to the process:

    No. Characteristics Measurement unit initial optimized Standard

    1. Length density Nm 49,4 50,8 SR EN ISO 2060Cv% 6,0 4,7

    2. Break force cN p% 259 3,6 218,7 4,8 SR EN ISO 2062Cv% 9,5 12,5

    3. Break elongation % p% 5,75 5,83,7Cv% 13,0 9,6

    4 Break length Km 12,8 11,15. Torsion t/m p% 10011,9 988,91,4 SR EN ISO 2061

    Cv% 4,9 3,8tex(m) 4501(142) 4389(139)

    6. USTER Irregularities Cv% 22,9 22,3 SR ISO 2649-997. USTER Imperfections

    Nr./1000mThin places 390 405

    Thick places 1886 1700neps 1174 1653

    8. Hidrofilicity (static immersion) % 203,43 233,49 Laboratory procedure

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  • 558 I. Dumitrescu et al.

    Environment: the reducing of the waste water pollution resulted from discharging lowerquantities of toxic chemical compounds (by 44.3%) and the elimination of phosphates; thediminishing of the greenhouse effect by reducing the carbon dioxide emissions (2500 t/year)into the atmosphere; the conservation of the natural resources of water (50%) and naturalgas (45.8%).

    Business efficiency: lower production costs with no loss of quality; quality maintained atthe level required by the market; additional savings through lower labour costs, shorteroperating time, and the reduction (by 50%) of the taxes paid for pollution.

    Table 9. The yarn dyeing fastness

    Yarns dyed according to the process: Standard

    No. Dyeing fastness to: initial optimized

    1. Household and industrial washings 40C

    Staining: 4 4 -5 SR ISO 1833-95

    Colour modification: diacetate/cotton/pa/pet/acr/wool

    4-5/3/4-5/4-5/4-5/4-5 4-5/4-5/4-5/4-5/4-5/4-5

    2. Water Staining: 4 -5 4 -5 SR EN ISO 105/E01Colour modification: diacetate/cotton/pa/pet/acr/wool

    5/4-5/4-5/5/5/5 5/4-5/5/5/5/5

    3. Acid perspiration Staining: 4-5 4-5 SR EN ISO 105-E04-98Colour modification: diacetate/cotton/pa/pet/acr/wool

    5/4-5/4-5/5/5/5 5/4-5/5/5/5/5

    4. Alkaline perspiration

    Staining: 4-5 4-5 SR EN ISO 105-E04-98

    Colour modification: diacetate/cotton/pa/pet/acr/wool

    5/4-5/4-5/5/5/5 5/4-5/5/5/5/5

    5. Rubbing Dry: 4-5 3 SR EN ISO 105-X12-98Wet: 2-3 2-3

    6. Iron pressing Colour modification after pressing

    4 4 SR EN ISO 105-X11

    Colour modification after 4 hours

    4-5 4-5

    Colour bleeding 4-5 4-57. Artificial light (XENON lamp) 4 4 ISO 105 B02-84

    Note: pa: polyamide; pet: polyester; acr: acrylic.

    Table 10. The cleaner process financial effects

    COSTS, $/kg yarns Savings

    No. Material Initial process Cleaner process (%)

    1. Water 0.0325 0.0162 502. Effluent taxes 0.0195 0.00974 503. Electric energy 0.0250 0.0161 35.64. Steam 0.1689 0.0960 43.35. Natural gases 0.0307 0.0476 45.86. Chemicals 0.3186 0.1774 44.37. TOTAL 0.5952 0.363 44.38

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  • Cleaner production in Romanian textile industry 559

    This paper presents the benefits resulted from introducing the clean technology of 100%cotton fibre pre-treating-dyeing employed by Novatextile Pitesti, Romania. The quantifica-tion of the outcome has been established through the following methods: the balance of rawmaterials, electric and thermal energy; the analysis of the water quality indicators resultingfrom the various stages of the process; the comparative analysis of the fibres dyed through thetraditional and clean technologies; the study of the economic impact of the clean technology.

    The clean technology now in use ensures:

    73% reduction in the chemical auxiliaries used for finishing the cotton yarns; 50% savings of clean water; 35.6% savings of electric energy consumption and 45.8% savings of thermal energy

    consumption; reduction of carbon dioxide emission by 2500 t/year; 50% reduction of effluent costs; compliance with current Romanian national legal requirements in environmental respects,

    themselves complying with those of the EU.

    Acknowledgements

    Many thanks to Dr Vasile Rugina, S.C. ICEMENERG S.A, for calculation of the thermalenergy consumptions (Appendix 1). We thank eng. Florina Pricop, S.C. LACECA S.A., forcollecting the relevant data of the study case and to technical director of Novatextile, eng.Mihai Popa, for the support and access in the enterprise.

    References

    [1] UNEP, 1994, Government Strategies and Policies for Cleaner Production. Available online at: http://www.agrifood-forum.net/publications/guide/f_chp1.pdf.

    [2] Available online at: http://www.dialogtextil.ro/arh/2003/nov_2003/cuprins2.htm.[3] Available online at: http://www2.mst.dk/common/Udgivramme.[4] Waste Minimisation Guide for the Textile Industry, 2000, A Step Towards Cleaner Production (Volume 1)

    January. Available online at: http://www.c2p2online.com/documents/Wasteminimization-textiles.pdf.[5] Schnberger, H. and Schfer, T., 2003, Best Available Techniques in Textile Industry, Research Report 200 94

    329 UBA-FB 000325/e, Federal Environmental Agency (Umweltbundesamt), Berlin, March 2003. Availableonline at: http://www.umweltdaten.de/publikationen/fpdf-k/k2274.pdf.

    [6] Mattioli, D., Malpei, F., Bortone, G. and Rozzi, A., 2002, Water minimisation and reuse in the textile industry,in: P. Lens, L. Hulshoff Pol, P. Wilderer and T. Asano (Eds) Water Recycling and Resource Recovery in Industry(London: IWA Publishing). Available online at: http://www.life-battle.bologna.enea.it/files/pubblicazioni_varie/De_Florio,_L._Investigation_on_textile_industry_wastewater_r.pdf

    [7] Catalases for low water textile processes, EU-Project: BRITE/EURAM 3, BRPR 988004, 2001, availableonline at: http://dbs.cordis.lu

    [8] NTPA-002/2002, Romanian Government Ordinance no.188/2002, Standard regarding the conditions for thewastewater discharge into the city sewage or directly into the water cleaning plant, Official Monitor, Part I nr.187, 20 March 2002.

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  • 560 I. Dumitrescu et al.

    Appendix

    The calculation of the thermal energy consumptionsThe specific THERMAL ENERGY consumptionsThe data taken from the enterprise records show a total steam consumption of 767.4 kgssteam, for 200 kgs yarns, in the case of using the old boilers, and of 596 kgs steam, in thecase of using the new boilers.The specific steam consumption

    The thermal energy consumption was calculated according to the formula:ET = cs steam x (i1 i2)Where:

    - ET = thermal energy consumption for preparing 1 kg yarns;- cs steam = specific steam consumption in kg steam/kg yarns- cs steam = 3.84 kgs of steam/kg of yarns in the initial process- cs steam = 2.98 kgs of steam/kg of yarns in the optimized process- i1 = the enthalpy of the 6 bar saturated steam in entering into the technological

    installation.

    According to the tables with the steam characteristics, the enthalpy is: i1 = 2757 kJ/kgRemark: although the boilers in the power station have the nominal pressure of 8 bar in thesteam produced, the enthalpy of the 6 bar dry saturated steam was calculated as it is lessprobable that it functions under nominal pressure owing to the losses on the route from thethermal power station to the installation.

    - i2 = the condense (steam) enthalpy at the installation exit

    It was considered that the installation is endowed with steam trap and the steam temperatureis 60C for i2.

    Thus: i2 = 251.6 kJ/kg.Under these circumstances:In the initial process:

    In the optimized process:

    The specific thermal energy saving is (for 1 kg yarns) is:

    767 4. kgs of steam

    200 kgs of yarns=

    3.84 kgs of steam

    kgs of yarns

    ET = 3 84. kg of steam

    ETkg steam

    kf yarns kg steam kf yarn kf yarn= ( ) = =3 84 2757 251 6 9620 7 9 62. * . . .

    kJ kJ MJ

    ETkg steam

    kf yarns kg steam kf yarn kf yarn= ( ) = =2 98 2757 251 6 7466 09 7 47. * . . .

    kJ kJ MJ

    9 62 7 47 2 15. . .MJ MJ MJ

    kf yarns kf yarn kf yarn =

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  • Cleaner production in Romanian textile industry 561

    The thermal energy saving for all the processed material (200 kgs) is:

    One can see that, by introducing the new technological process, one can obtain specificheat energy savings of 2.15 MJ/kg yarns, 430 MJ for the 200 kgs processed batch,respectively.

    If only the carded yarn production of 1960 t/year were taken into consideration, withouttaking into account the 12,000,000 m2/year that result from the finishing department, the heatenergy savings would range up to 4,214,000 MJ/year.

    The methane gas consumption

    The natural gas consumption was calculated according to the formula:

    where:

    - CGN = natural gas consumption;- ET = the thermal energy quantity produced/delivered by the power station;- ETA = the power station boiler output (in %);- PC = the natural gas calorific power, equal to 34,750 MJ/Nm3.

    The natural gas consumption in the two processes is:

    With old boilers (ETA = 64%)

    The initial technological process

    - The specific natural gas consumption in the thermal power station is:

    The total consumption for 200 kgs yarns is:

    With new boilers

    The cleaner technological process

    - The specific natural gas consumption in the thermal power station is:

    2 15 20 430. *MJ

    MJkf yarns

    0 kg yarns =

    CGN =ET

    ETA PC**100

    CGNSPkg yarns

    32 Nm / kg yarn3= =9 62

    64 34 750100 0 4

    3

    .

    * .* .

    MJ

    MJ

    Nm

    CGNNm

    Nm= =0 432 200 86 43

    3. * .kg yarns

    kg yarns

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  • 562 I. Dumitrescu et al.

    - The total consumption for 200 kgs yarns is:

    CGNSPkg yarns

    4 Nm / kg yarns3= =7 47

    92 34 750100 0 23

    3

    .

    * .* .

    MJ

    MJ

    Nm

    CGNkg yarns

    0 kg yarns= =0 234 20 46 83

    3. * .Nm

    Nm

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