lessons from cleaner production experiences in indian hosiery clusters

Journal of Cleaner Production 9 (2001) 325–340www.cleanerproduction.net

Lessons from cleaner production experiences in Indian hosieryclusters

Venkatesan Narayanaswamy*, J. Ashley ScottSchool of Environmental Engineering, Faculty of Environmental Sciences, Griffith University, Nathan Campus, Queensland 4111, Australia

Received 18 April 2000; accepted 9 August 2000

Abstract

This paper focuses on lessons learnt from Cleaner Production (CP) experiences in textile bleaching and dyeing (hosiery) clustersin India. The regional and industry contexts for CP are demonstrated by outlining the interaction and interdependency between theurban and rural environment, and an industry cluster centered on Tirupur City. A policy for fostering water use productivity in theindustry cluster is discussed, which shows how that in order for resource productivity to be maintained, regional and industry CPstrategies should be aligned. This is illustrated by a discussion on CP lessons in water and chemicals conservation. The paper alsorecommends future areas of CP investigations required in the industry to make it ecologically sustainable in the long-term. 2001Elsevier Science Ltd. All rights reserved.

Keywords:Cleaner Production; Hosiery; Industry clusters; Resource conservation; Water pricing

1. Introduction

Industrial clusters in India have been developmentnuclei for surrounding urban societies that contrast shar-ply with the nearby rural setting in terms of populationdensity, natural resource consumption, infrastructurefacilities, basic amenities, public health, education, andenvironmental quality. One of the most significant ofthese clusters is an exporting hosiery (cotton knittedinner-garments, T-shirts and sweaters) centered on Tiru-pur city in southern India. In 1999, this hosiery clusteraccounted for more than 90% of India’s knitwear exportsto Western Europe, USA and Japan. Total export earn-ings amounted to around US$1000 million [1] and a 10%per annum growth rate is expected. Current output corre-sponds to an annual production of 145 000 tonnes of fab-ric [2], primarily in the form of T-shirts and sweaters.

For the past ten years, hosiery clusters have been con-stantly subjected to international and local environmentalpressure with regard to meeting local and internationalenvironmental standards in textile wet processing. Inter-

* Corresponding author. Tel.:+61-7-3875-7202; fax:+61-7-3875-5288.

E-mail address: [email protected] (V.Narayanaswamy).

0959-6526/01/$ - see front matter 2001 Elsevier Science Ltd. All rights reserved.PII: S0959-6526 (00)00073-1

national eco-textile standards (especially of Germany) ontoxicity of fabric were responded to positively with thehelp of the world’s leading dyestuff manufacturers.Initiatives of international organizations coupled withlocal environmental pressure mainly addressedgroundwater abstraction and contamination by the was-tewater releases from the dye houses. The cluster hasbeen responding to these pressures in various ways, bothfrom within individual operations and as an industrygroup.

2. Context and framework for sustainabledevelopment of a hosiery cluster

Every industrialized state in India is characterised bycluster(s) of small and medium sized industries that pro-pel local economic development. In some areas, the clus-ters are homogenous comprising of industries that manu-facture and market a similar type of products or belongto the same product chain. In others, clusters are hetero-geneous, perhaps consisting of more than one homo-geneous cluster. A map1 of selected major industrial

1 This map is primarily intended to show the location of Tirupurhosiery clusters vis-a`-vis other similar industrial clusters located in

326 V. Narayanaswamy, J.A. Scott / Journal of Cleaner Production 9 (2001) 325–340

clusters, including the Tirupur hosiery cluster, has beenproduced [3] and is shown in Fig. 1.

These industrial clusters create their own urban cen-ters, which are embedded in a “traditional” rural econ-omy and ecosystem. The rural ecosystem is relied uponto supply and shares natural resources with, and assimi-lates wastes discharged from, the industries and urbancentres. However, rapid expansion of the cluster’s indus-trial estates and hence their urban centres, have been

Fig. 1. Location of major industrial clusters in India.

other parts of India. The map disclaims any territorial accuracy oninternationally disputed Indian borders.

slowly engulfing their supporting rural ecosystem. Amodel depicting such an interaction is given in Fig. 2.

Tirupur hosiery cluster is a classic example of themodel in Fig. 2 and an overview of environmental per-formance of the cluster and Tirupur City is summarisedin Table 1 [4].

In general, failure to enforce resource conservation inindustrial clusters has inhibited faster technologicaladaptation to curb water and solid waste pollution. Indi-

vidual units within these clusters have been traditionallycompeting mainly on the grounds of cheap unskilled lab-our and low overheads due to minimal expenditure ontechnological safeguards for the environment, althoughin some cases the situation has been recently changing

327V. Narayanaswamy, J.A. Scott / Journal of Cleaner Production 9 (2001) 325–340

Fig. 2. Interdependency between industrial clusters and the ruralenvirons.

towards a better direction. The rapid rate of populationmigration from rural areas to the town and negligencewith regards proper town planning to cater to the basicamenities of growing settlements has led to inadequatesanitation and other basic amenities.

A move towards sustainable development of urbanTirupur would, therefore, not only comprise the hosierycluster, but also include development of a cohesive strat-egy that underscores a comprehensive developmentstrategy for the rural areas based on the availability oflocal knowledge and skills. The clusters and the urbancentres need to become resource productive especiallywith shared natural resources such as water, land, andenergy, in order to ensure long run resource suppliesfrom their rural environment.

As a consequence, a clear resource pricing policy thatrewards resource productivity and a more stringentenforcement initiative that discourages inefficient use isrequired. A comprehensive geographic information sys-tem on industrial clusters and urban–rural interdepen-dencies would aid policy makers to adequately plan forregional sustainability by proper zoning and siting ofindustrial clusters and their urban centres.

3. A synthesis of experiences from regional studies

A material flow analysis study [5] provided a compre-hensive view of the hosiery cluster’s ecological problemsand prescribed water and energy conservation measureson a regional scale. Thermal evaporation of wastewaterto produce and reuse salt and water in the wet processingwas one of the solutions successfully implemented in afew units in Tirupur with initiatives taken by inter-national organisations. Incineration of industrial andmunicipal wastes along with traditional fuels to generateelectricity to ease the frequent power cuts, is one of theemerging energy solutions in Tamil Nadu.2 Increasingly,

2 In Perungudi, a small suburb near Chennai the capital city of thestate of Tamil Nadu, an incinerator project was formally kicked-offduring September 1999 to generate electricity by the gasification ofmunicipal solid waste collected from the Chennai City. Therefore, this

sustainable solutions in the form of adaptive and selec-tive networking are likely to emerge in the near future[6]. However, this scenario can only be further strength-ened if individual process units are encouraged to inno-vate.

3.1. Pricing water — a policy to push resourceconservation forward

One of the policy means to foster productivity in theuse of shared natural resources could be to price themequitably to promote their efficient use among industrial,domestic and agricultural purposes. As can be seen inTable 1, ground and surface water reservoirs in andaround Tirupur are one of the precious natural resourcesshared by the hosiery cluster with its rural surroundings.In order to address an acute water scarcity in Tirupur,an integrated water supply and sewerage project wasproposed in 1998 and started off in 1999. A synopsis ofthe project is given in Box 1 [7] (Table 2).

The proposed project aims to provide an uninterruptedsupply of clean water to industry, households and nearbyvillages, as well as construction of a sewerage systemwithin the town’s municipal area to provide low costsanitation for slums, domestic wastewater treatment andsludge disposal facilities.

Nearly 80% of the water supplied by this project tothe hosiery industry will become wastewater and will gettreated either at the eight Common Effluent TreatmentPlants (CETPs) or at the individual units. The treatmentplants are primarily designed to shift toxic organics fromwastewater to sludge. Estimated annual 50 000–65 000tonnes of wastewater treatment plant sludge containingtoxic dyes and chemicals will have to be secured-land-filled to comply with Indian hazardous waste manage-ment regulations. However, the secured-landfilling costsare expected to add a substantial financial burden to theindustries and as a consequence, it is anticipated that thewastewater, even after treatment, will continue to con-tain toxic chemicals and will be unfit for use in theindustry or for irrigation.

Given the above scenario, pricing water by the cost ofwater treatment alone will subsidise water and chemicalabuse in hosieries. A rational water pricing policy wouldcomplement the integrated water supply project byencouraging a wider adoption of cleaner productionmeasures to benefit both the industries and the localcommunities.

3.2. A process differentiated pricing policy for waterto promote efficient use

Full cost pricing of water should include a marginalscarcity rent of the water as a resource [8], positive and

confirms the need for such emerging patterns of regional energy con-servation projects in industrialised cities as cited in [5].


Table 1Major environmental indicators of the hosiery cluster and urban Tirupur

Population Around 400 000Industry Predominantly, cotton knitwear bleaching, dyeing, printing and knitting. More than 4000 small and

medium enterprises (SMEs) are currently functioning in and around Tirupur. The average factory costof a T-shirt is around US$ 2.00 (as per 1997 exchange rate).

Area Around 44 km2

Land use pattern Residential: 37%Commercial: 4%Industrial: 10%Public: 13%Agriculture and vacant land: 36%

Housing Around 150 000 houses, of which more than 70% lack a toilet facility and safe drinking water. 23%of the houses do not have electricity connections and 10% do not have all the three basic amenities.

Slums There are 88 slums in Tirupur and 70 in the city-outskirts. Average monthly per capita income of aslum is around US$5. 90% of slum houses are without toilet facilities and 30% without safe drinkingwater. Total human population residing in the slums is around 90 000 (23% of the total Tirupurpopulation).

Water source The water table, on an average, is 65 m below the ground level, has a TDS of around 1000 mg/l. 150borewells are currently in operation. The river Bhavani, a monsoon driven, non-perennial river,located 55 km southwest of Tirupur is another major water source. Ten villages located at a distanceof 2–37 km from the city provide water to industries. Private vendors abstract water from thesevillages and sell it to industry @ US$0.7 per m3. These vendors cater to 90% of industrial needs and10% of domestic water requirement.

Water consumption The cluster alone consumes around 150M l of water every day. More than 50% of this volume isbrought to the city from surrounding villages by trucks at a total cost of US$6 million per year.Households consume around 75M l/day day and roadside villages consume around 50M l/day.Average per capita daily consumption is 85 l in the rainy season and 35 l in summer

Sewerage and drainage Total road length of the Tirupur municipality is around 343 km with less than 18% of roads havingstorm water drains. Sewage from the drainage system flows untreated into a dry river Noyyal.

Sanitation Less than 50% of households have toilet facilities. Sewage from households is discharged in opendrains. Low cost sanitation schemes existing in the outskirts of the city do not exist in the city itself.No sewage treatment and disposal facilities are available currently for the city.

Solid waste management An estimated 3500 tonnes of paper wastes, 9500 tonnes of textile rags and threads, 60 tonnes ofplastic wastes are generated annually by the cluster. In addition, over 40 000 tonnes pa of ashes aredisposed of, such that in total, the industry contributes nearly 53 000 tonnes pa to municipal solidwaste.An estimated 91 250 tonnes pa of domestic solid waste are generated. On an average, 63% of themunicipal solid waste is collected and composted in a 1.5 ha yard located one kilometre from thecity. An estimated 2500 tonnes of plastic, 25 500 tonnes of waste rags and 20 tonnes of metals arecollected annually and sold outside the city for recycling and reuse. A centralised solid wastemanagement facility to handle all these wastes is still at the proposal stage.

Energy consumption The city consumes 115 M kWh pa of electricity, of which industry consumes 56%; commercialfacilities 13%; public use 2% and residential 2%. Most firms and commercial units have dieselgenerators to help cope with erratic supply. Bleaching and dyeing units consume about 500 000tonnes pa of fuel wood chopped from the nearby rain forest of the Nilgri hills in Western Ghats.

Vehicular traffic Highly congested due to narrow earthen roads.Noise and air pollution Very high in the city, exceeding local standards at least by 10–15 times.Health effects There are poor health facilities in the city, with only 1000 beds (inclusive of government and private

hospitals) for 400 000 people. Cardiac arrest causes 38%; respiratory failure 17%; and dysentery,diarrhea and fever 2% of total deaths annually.

Water pollution Around 1800 tonnes of dyes are consumed annually by the cluster of which 500 tonnes are releasedannually into wastewater streams. Around 50 000 tonnes of chemicals other than dyes are consumedannually, the majority of which passed into the wastewater untreated and unrecovered. Totalwastewater discharge from around 4000 hosiery units is around 140M l/day.Around 464 units in the cluster have their own treatment plants, of which 40 have been closed downby state high court orders due to non-compliance with the local pollution laws. In addition, the courthad ordered all the hosiery units to clean up a nearby dam that has become unsuitable for irrigationdue to direct discharge of untreated effluents. Nearby surface water sources, tube wells and borewellsat a depth of 90–150 m are also contaminated with chemical pollutants released by the clusters.Riverine and ground water quality in and around Tirupur exceeds World Health Organisation (WHO)standards for potable water by 20–30 timesSince July 1999, there are now 8 common effluent treatment plants in and around Tirupur. The totalestimated capital cost of these plants was around US$30 million including the cost of conveyance.The estimated recurring costs are up to US$7.5 million per annum.


Table 2Box 1. Privatisation of water supply, sewage treatment and disposal in Tirupur City

Under the auspices of the Government of Tamil Nadu, privatisation of water supply and sewage treatment was formally initiated on 21January 1999 by the signing of an agreement with the New Tirupur Area Development Corporation (NTADC). The consortium will startoperating and maintaining the project by 2001 when water will be taken from the Bhavani River, and treated and supplied to industries andhouseholds through a pipe network. The estimated project outlay is US$282–353 million over an economic life span of 30 years. Duringthe first year, water to the hosiery industry cluster and households will be costed on an ad hoc rate basis and from the second yearonwards, the water price will be linked to actual water treatment costs adjusted to changes in nominal prices. It is estimated that 21roadside villages with a population of 710 000 as well as 650 000 people in Tirupur municipal area will benefit from the project.

negative external effects of water abstraction, and thirdparty effects when it is transferred across basins. Thereare generally two ways of addressing externalities inwater pricing:

O create a market where none exists;O find ways of stimulating the prices for scarce water

resources.

In both the cases, consideration of externalitiesinvolves not an issue of “if”, but of “when and how”environmental factors will be addressed. An expectedoutcome of full cost pricing of water resources is pro-motion of high water use efficiency levels. One way toaddress this directly is to internalise the marginal costof water recovery and reuse in the price of water. Thisapproach is relatively easy when firm specific costsinformation is available. This is also further justified bythe fact that there are increasing uncertainties in the datarequirements and techniques of estimation of externalenvironmental and social costs of water abstraction.

Waste minimisation and water conservation studiesconducted at individual units of Tirupur showed thatnearly 80% of the total water consumed could be repro-cessed and reused [9]. In addition, the reclamation andreuse of wastewater will minimise usage of chemicalsand dyes. It was also found, however, that currently thiswas not considered economically attractive due tosuboptimal pricing of water.

Applying the central policy prescription of microeco-nomics, the price of water for industrial use should beequal to its marginal cost of reclamation and reuse. How-ever, the equation works under the following assump-tions:

O There is aperfect competitionamong suppliers ofwastewater reclamation and reuse techniques.

O Capital and annual operating costs of wastewaterreclaiming and reuse are directly proportional to thevolume of wastewater handled and hence the waterrecovered and reused. Therefore, the marginal cost ofwater reclamation is equal to its unit cost. Cost curvesas shown in Fig. 3 (as an example) and Table 3(a)and Table 3(b) [10] (for the individual units and cen-tralised cooperative facilities) indicate that the annu-

Fig. 3. Total cost function of a centralised water reclamation facilityfor bleaching units.

alised capital and operating cost functions are linearagainst different volumes of water recovered. There-fore, the slope of the total cost curve in each case isthe marginal cost of water recovered.

O All the costs were estimated in 1997 real prices. The1997 exchange rate was used in converting IndianRupees to US Dollar. Yearly adjustments should bemade based on a suitable pricing index to arrive ateach year’s price and exchange rate. The final priceof water is therefore dynamic and varies every yearsubject to changes in 1997 real prices.

O The marginal cost of water reclamation and reuse is asum of marginal costs of in situ pollution prevention,wastewater treatment by physico–chemical, biologi-cal, and polishing filtration methods and the recoveryof water by reverse osmosis. The marginal cost isinclusive of the treatment and disposal of rejects tocomply with the local discharge limit for total dis-solved solids (2100 mg/l) [11]. The marginal cost ofwater reclamation does not include the marginal costof sludge transportation and secured disposal. How-ever, these costs could be added on when the central-ised solid waste disposal facilities are established.

O Cost of capital is assumed to be 15% (real rate) perannum and the economic life of all treatment techno-logies to be around 20 years. The individual and cen-tralised water reclamation plants are assumed to oper-ate 330 days per year.


Table 3(a)Cost data for centralised water reclamation facility for hosiery clusters

Water reclamation capacity (m3/year) Annualised costs in 1997 US$Capital Operating Total

Bleaching mills1485000 145947 518165 6641121262250 143325 446666 589991742500 70158 274598 344756742500 67918 262228 330147623700 59829 234722 294551237600 30609 99153 129761Bleaching and dyeing mills2640000 375292 1332424 1707715.82244000 368551 1148569 1517120.11320000 180407 706109 886515.31320000 174647 674302 848948.41108800 153845 603572 757416.6422400 78708 254965 333672.3Integrated mills3300000 416991 1480471 18974622805000 409501 1276188 16856891650000 200452 784565 9850171650000 194052 749224 9432761386000 170939 670635 841574528000 87453 283294 370747

The marginal costs of water reclamation and reuse areestimated for two scenarios (i.e. at the individual unitlevel and at the centralised cooperative facility level).Furthermore, these two scenarios were subdivided underthe three categories of bleaching, bleaching and dyeingand integrated mills.3 The estimated marginal cost ofreclamation and reuse of water and its impact on factorycost of production [12] are given in Table 4.

Due to lower economies of scale achieved from a cen-tralized water recovery plant, the estimated price ofwater at the cooperative facility is cheaper than thatderived at the individual unit level. However, in both thecases, the price of water is cheaper for the bleachingprocess and more expensive for bleaching and dyeingprocesses in proportion to their water consumption andcost of water recovery from each process. Though thepricing norm takes into account the units that are con-nected to the existing centralised wastewater treatmentfacilities and those having their own on-site facility, thewater pricing should be based on the process-wise waterconsumption pattern at the unit level in order to stimulateresource conservation measures at the factory level.

The savings accrued from reduced water, energy, andchemicals usage have been estimated to be 8–10 UScents per T-shirt [13], a level that could absorb a mar-ginal increase of say 7–7.5 US cents per T-shirt in thefactory production cost. Therefore, the water pricingmay not have an adverse effect on the net real selling

3 An integrated mill is where scouring, bleaching, dyeing, printing,and finishing are carried out under the same roof.

price of a T-shirt in the export market. On the contrary,projecting green attributes of the product could enhancethe current competitive position of Indian hosieryexports in the international market. The revenues gener-ated from water pricing could be reinvested in extendingwater supplies and sewerage systems especially to vil-lages, which in the region under study is particularly rel-evant to those currently dependent on water from theRiver Bhavani.

A critical success factor for pricing to effect thedesired behavioural change among the hosiery units isthat the current environmental regulatory and enforce-ment regime should shift from “end-of-pipe” pollutionlimits to “prevention-at-source”. This could be only ach-ieved by educating the regulators and environmental pol-icy makers about the potential socio–economic benefitsof cleaner production and resource conservation to thelong-term sustainability of industrial clusters in theurban–rural niche [14]. Backed by such proactive regu-latory support, pricing water by its efficient use wouldgive substantial additional economic leverage to adoptresource conservation measures at the regional level.This goal is not unreasonable given that there are wellequipped local pockets of institutional assistance in andaround Tirupur, such as textile research associations,industry associations, international standards institutions.Some of the on-going programs such as “Waste Minimis-ation Circles” of the Ministry of Environment and For-ests, Government of India, could also be effectively util-ized to push the hosiery units on self-initiated resourceconservation projects.


Table 3(b)Cost data for individual water reclamation facilities for hosiery clusters

Water reclamation capacity (m3/year) Annualised costs in 1997 US$Capital Operating Total

Bleaching mills59400 6242 51027 5726851975 7118 42603 4972144550 4892 36778 4167074250 7665 64762 7242729700 3949 24954 2890244550 6845 39370 4621544550 4869 40708 4557629700 3192 25921 2911329700 3586 28513 3210029700 3455 28503 3195729700 4212 27622 3183414850 1639 14132 1577114850 1534 13607 15141Bleaching and dyeing mills105600 16050 131211 14726192400 18304 109551 12785579200 12579 94572 107151132000 19709 166531 18624052800 10154 64166 7432079200 17601 101238 11884079200 12519 104677 11719652800 8209 66654 7486352800 9221 73320 8254252800 8883 73292 8217552800 10832 71028 8186026400 4214 36339 4055326400 3944 34990 38934Integrated mills132000 17833 145790 163623115500 20338 121723 14206199000 13977 105080 119057165000 21899 185034 20693366000 11282 71296 8257899000 19557 112487 13204499000 13910 116308 13021866000 9121 74060 8318166000 10246 81467 9171366000 9870 81436 9130666000 12035 78920 9095533000 4682 40377 4505933000 4382 38878 43260

Table 4Estimated water price and its impact on factory cost of production

Parameters Individual facility Centralised cooperative facilityBleaching Bleaching and Integrated mill Bleaching Bleaching and Integrated mill

dyeing dyeing

Marginal cost of recovery of 1 m3 of 0.94 1.4 1.2 0.44 0.64 0.56water or water price (1997 US$)Percent increase in factory cost of 1.7 3.8 2.6 0.8 1.8 1.2production


4. A synthesis of cleaner production experiencesfrom on-site industry studies

To help initiate better working practices, eight inte-grated hosiery mills were audited [15] for designing andimplementing cleaner production measures. All the millswere processing 3500 tonnes of cotton fabric per annumwith an annual sales turnover of around US$25 million.The main operations carried out in the units includedfabric purification, bleaching, dyeing, printing and fin-ishing. A preliminary process study was conducted fol-lowed by a one-week intensive in-plant workshop on cle-aner production. A waste minimisation team comprisingall layers of line management was then formed at eachsection of the production unit. Senior management coor-dinated the teams on formulating, testing andimplementing improvement measures.

Schematics of process flow diagrams of the most pol-luting processes, such as dyeing and printing, are givenin Figs. 4–6.

Typical resource consumption and wastewater charac-teristics are presented in Table 5 [16], which provides abroad range of scope for process improvement to helpconsistently reduce resource consumption and chemi-cal pollution.

The average characteristics of a sequence of wastestreams from scouring and bleaching operations in winch

Fig. 4. Process schematic of soft-flow dyeing technology.

and soft-flow machines are presented in Figs. 7 and 8[17].

The average characteristics of a sequence of wastestreams from dyeing dark, medium and light shades inwinch and soft-flow machines are presented in Figs. 9–14 [18].

The data presented in Figs. 7–14 were mainly usedto identify shades that contribute more chemical oxygendemand (COD) and total dissolved solids (TDS) pol-lution, and to identify redundant wash stages that hadlittle or no impact on the required quality parameters offinished fabric. In addition, several rounds of qualitytesting of the fabric were carried out before and afterprocess changes to ensure that all the quality criteria ofthe fabric were met at each and every process stage.

A number of waste minimisation options have sub-sequently been implemented in bleaching, dyeing andprinting sections of the hosiery industry. Some notableones are summarised below:

4.1. Elimination of redundant washes

Similar analyses to those shown in Figs. 7–14 helpedthe cleaner production teams to identify redundant coldand hot washes, and soap washes. Quality testing of thefabric for various shades subsequent to the eliminationof the redundant washes showed no deterioration in the


Fig. 5. Process schematic of winch dyeing.

Fig. 6. Process schematic of rotary screen-printing.

colour fastness, luster and pH of the fabric. The redun-dant washes were then eliminated saving around 60m3/day of water (approximately 10% of total averagedaily water consumption).

4.2. Elimination of the bleaching step for dark shades

Bleaching was tested to have no extra impact on thequality of dark-shade dyed fabric. Therefore, this stepwas eliminated for a few dark shades such as black, deepblue, red and deep violet.

4.3. Elimination of softener use prior to bleaching

The softener used was found to be unnecessary in thebleaching stage, as impurity removal had already beenaccomplished by alkali scouring. This resulted in a sub-stantial reduction of surfactant release into the wastewater.


Table 5Average resource consumption and water pollution loading figures from hosiery production

Process step Water Consumption Energy Consumption CODa g/kg fabric TDSb g/kg fabriclitre/kg fabric MJ/kg fabric

Desizing 5–10 4–8 100–110 –ScouringWinch (Beck) 5–10 5–10 90–100 130–150Soft flow (Jig) 3–5 4–6 40–60 70–80MercerisationWinch (Beck) 30–45 20–30 6–10 400–500Soft flow (Jig) 15–20 12–15 2–5 180–380BleachingWinch (Beck) 65–85 50–60 200–310 200–270Soft flow (Jig) 25–30 25–30 100–150 120–150DyeingWinch (Beck) 60–85 40–56 600–700 3000–3500Soft flow (Jig) 30–45 26–32 300–410 1500–2000PrintingRoller 50–70 100–120 310–350 250–300Rotary Screen 20–30 45–55 90–100 70–80Finishing 100–200 15–22 150–250 120–150Total range 200–505 130–306 780–1830 2060–4870

a Chemical oxygen demand.b Total dissolved solids.

Fig. 7. Average characteristics of sequence of waste streams fromscouring in winches (becks).

4.4. Substitution of chemicals

A range of chemical substitutions at various stages inthe production process has occurred. For example hypo-chlorite was substituted with hydrogen peroxide (H2O2)during bleaching to reduce total dissolved solids andimprove fabric quality before dyeing. Trichloroethylene(TCE) was traditionally being used in the cleaning ofprinting screens. After exhaustive laboratory testing, itwas found that mineral turpentine oil, which is the oilcarrier of printing paste, removes the paste adhered to

Fig. 8. Average characteristics of sequence of waste streams frombleaching and scouring in soft-flow machines (jigs).

the screens better than TCE. This resulted in completeelimination of TCE use in production.

As a part of overall product specification, carcinogenicdyestuffs have not been allowed in T-shirt manufacturesince the enforcement of eco-textile regulations byimporting countries such as Germany and the USA.These regulations forced the units to work closely with


Fig. 9. Average characteristics of sequence of waste streams fromdark shades dyeing in winches (becks).

Fig. 10. Average characteristics of sequence of waste streams fromdark shades dyeing in soft-flow machines (jigs).

their dyestuff suppliers to substitute azo and amino dyeswith non-toxic dyestuff [19].

Due to total dissolved solids pollution in the waste-water and added difficulties of water reclamation andreuse, reactive dyes with high exhaustion and those thatconsume a relatively small quantity of salt during reac-tion with the fabric were substituted for high-salt low-

Fig. 11. Average characteristics of sequence of waste streams frommedium shades dyeing in winches (becks).

Fig. 12. Average characteristics of sequence of waste streams frommedium shades dyeing in soft-flow machines (jigs).

exhaustion dyes. This resulted in a reduction in specificconsumption of salt from 0.63 to 0.45 kg/kg of fabric.

Dyeing of brown, green and white colours werereplaced by naturally coloured cotton fabric [20]. Thereported savings were in terms of a 60% reduction inthe cycle time of T-shirt production, as well as elimin-ation of certain dyes, chemicals and other additives usedin upstream operations such as desizing, scouring,bleaching, fixing and finishing. However, due to limitedavailability of a large range of natural colours and alsodue to the high cost of importation (import duty is more


Fig. 13. Average characteristics of sequence of waste streams fromlight shades dyeing in winches (becks).

Fig. 14. Average characteristics of sequence of waste streams fromlight shades dyeing in soft-flow machines (jigs).

than 50% of the total cost), large-scale substitution ofchemical dyeing is still under consideration and exper-imentation.

4.5. Controlled addition of chemicals

After the neutral wash, the pH of the wastewater wasfound to be low at below 5.0, indicating an excess useof acid. Subsequent controlled acid dosage using a digi-tal pH meter reduced acid use in the neutralization stepby 10%, by 23% after bleaching and by 62% before thefinishing stages. The same approach is currently beingextended for implementation in the bath and additivespreparation.

4.6. Reduction of water usage in roller and rotaryscreen-printing

Wastewater discharges from the printing sectionposed difficulties in treatment and disposal, and werefound not to meet stipulated discharge limits. Rollerscreen-printing was contributing more than 70% of thetotal wastewater from the printing section (Table 5). Asa consequence, washing cycles were eliminated both inroller and rotary printing by semi-automatic wiping ofprinting pastes from the printing machine ancillaries.This resulted in a 50% reduction in wastewater gener-ation and the paste was reused in subsequent operationcycles.

4.7. Technology upgradation in dyeing and printing

The superiority of soft-flow dyeing (jig) over tra-ditional winch (beck) dyeing in terms of enhancedresource productivity and as a result, reduced wastes andemissions, makes it the established best available tech-nique in the hosiery industry [21]. Typical bath liquorto fabric ratio for winch dyeing varies from 17:1 to 14:1and for soft-flow dyeing from only 7:1 to 5:1. Some ofthe winches were replaced by soft-flow machines [22]thereby reducing specific water and energy consumptionby respectively 30% and 50%. The cycle time for dyeingwas also reduced by 50% and this enabled the units toprocess more tonnage of fabric per unit time and withlower waste generation. The resulting improved capacityutilization led to enhanced productivity levels in the dye-ing plant.

Similarly, roller-printing machines were partlyreplaced by rotary screen machines to reduce by 50%,paste and other additive consumption. Complete replace-ment of roller printing by rotary screen-printing [23] andwinch processes by soft-flow processes is, however, cur-rently stalled. The older units are more labour intensiveand consequently one of the major obstacles faced bymanagement is the labour union’s resistance to potentialloss of jobs. It was feared by management that this mightin-turn cause high employee turnover in other sectionsof the mills, because job security is one of the key para-meters that attract and retain the best industry talent.

5. CP opportunities to be further investigated

Following are other cleaner production opportunitiesfor the hosiery industry that were identified as justifyingfurther investigation. All were considered as potentiallyproviding a positive transformation of the resource pro-file of the industry to bring in substantial long-term econ-omic gains.


5.1. Reconstitution and reuse of spent scour andbleach baths, and fixing and finishing baths

Bleaching and dyeing processes contribute morethan 80% of the total hydraulic loading, and alone,dyeing contributes around 60% of the TDS and CODloading in a typical hosiery factory. Therefore, thepossibility of reconstituting and reusing spent scour,dye, and bleach baths, fixing and finishing baths hasbeen gaining increasing scrutiny due to potentialenvironmental and economic gains [24]. Thoughreconstitution of the spent baths looks promising, threemajor hurdles are encountered while trying toimplement them on the shop floor:

O contamination of the fabric by dissolved impurities inthe spent baths;

O requirement of several dedicated hold-up tanks,pumps, and special analytical equipment for assessingresidual chemicals for reconstitution, enhances thecomplexity of logistics involved in a limited shopfloor space;

O additional labour hours to complete a process step.

However, factory units were willing to outsource theseactivities provided there existed a reliable outside facilitythat could reconstitute and recover spent baths. Localcleaner production experts and potential technology sup-pliers are consequently exploring the concept of mobileunits for recovering bath chemicals. However, such ameasure requires a policy push from the government inorder to ensure the participation of a large number ofcompanies.

5.2. Reconstitution and reuse of spent dye bath

The hydrogen ion of a reactive dye partly reacts withcellulose fibre and partly with the hydroxyl group ofwater in alkaline pH conditions. The rate of selectivityof these reactions depends on the type of reactive dyes(e.g. high or low exhaustion) used. As a result, the spentdye bath contains hydrolysed reactive dye with otherunreacted auxiliary chemicals including salt. It has beenargued that the hydrolysed dyestuff could be dehydratedby chemical (using agents such as potassium hydrogensulphate or concentrated sulphuric acid) and thermalmeans to restore the unexhausted dye [25]. If the regen-eration of dissolved dyestuff in water is proved feasible,in situ membrane separation of dye and salt from thespent bath [26] and consequently reconstitution ofreactive dye bath could then be achieved.

5.3. Standardisation of job orders and scheduling ofdyeing and printing colours

An improvement common to both dyeing and printingoperations is to standardise the shades demanded by

various job orders and incorporate them in systematicproduction sequencing. This is important for tworeasons:

O it simplifies in-bound logistics for storing the spentdye liquors, followed by potential recovery and reuseof the same in appropriate batches of identical shades;

O it minimises machine cleaning [27] (one of the bestways of sequencing is to group colours within famil-ies, i.e. red, blue and yellow and then run the dyeswithin one colour family from lighter to darker shadesor vice versa).

Currently, however, factory units generally operate to alarge extent with an ad hoc production plan that reactsto peak variations in the market demand. However, thissituation is likely to change with increasing structuralreorganisation taking place in the industry in the formof emerging new dedicated centralized facilities for dye-ing and printing. These facilities present potentialopportunities for implementing sound logistics manage-ment and chemicals recovery projects.

5.4. Membrane separation application in reclamationand reuse of process water from dyeing operations

A membrane technology supplier in collaborationwith a local engineering company conducted eight weeksof pilot testing of spent dye bath and significant rinsestreams [28]. The spent dye bath and significant rinseswere collected in a hold-up tank, oxidised by hypo-chlorite at an elevated temperature and the resultant saltsolution passed through two-stage membrane filtration[29]. The first stage was a nano-filtration followed by areverse osmosis (RO). The plant handled 40 m3 per dayof waste streams (initial salt concentration 24 g/l). Theplant produced around 16 m3 of fresh water and 16 m3

of concentrated salt solution (48 g/l) which was reusedin the dyeing process, with the remaining 8 m3 a rejectstream with roughly 24 g/l of salt and unoxidised dyeimpurities. This stream was diverted to the effluent treat-ment plant. The estimated payback period for a full-scaleinstallation was two years, excluding the treatment anddisposal cost of the reject stream.

However, there were two main reasons for notimplementing this option.

O chlorine was released as a secondary pollutant due tohypochlorite oxidation of spent dye bath, whichmeant the factory units would have to comply withadditional environmental legislation;

O with the inclusion of cost of disposal of the rejectstream, the payback period escalated to more thanfour years, which was well below the industry normto approve a capital project.


The cost-economics of membrane application inrecovering chemicals and water from dye waste streamscould be made more attractive by suitable policy inter-ventions that shift the industry’s compliance strategyfrom end of pipe to a CP approach. However, it is alsoimportant to resolve the above-discussed outstandingtechnical issues in applying the membrane separationtechniques to be able to market the CP approach moreattractively to the hosiery industry.

6. Conclusions and recommendations

The key industrial clusters in India, both as the valuedrivers of urban economic growth and as the majorresource sharers with their urban and rural environs,should attain continually higher levels of productivitywith the “shared” resources. One way of doing thiscould be to align CP strategies at the company andregional levels to focus on realising higher productivitygains in the consumption of shared resources. Always insuch cases, implementing CP strategies at the individualcompany level should be considered at the first instancefor two major reasons:

O to not impede those innovations that drasticallyreduce or eliminate the resource dependency of indi-vidual firms (a classic conflict between “sourcereduction” and “material and energy cascading”);

O to consolidate and strengthen long-term economicviability and ecological soundness of regional CPstrategies.

By using the hosiery cluster of Tirupur City inSouthern India as an example, an approach has beensuggested to describe resource interdependencybetween an industrial cluster, and its urban and ruralneighbours. The Tirupur example sets a context andbackground that emphasises the need for productivityof “shared” resources in the industry cluster. As anexample of water as a “shared” resource, a morerational water-pricing norm for the industry has beensuggested as a result of a survey of supporting studiesperformed in Tirupur.

In order to ensure long-term self-perpetuation ofregional resource conservation projects, individual fac-tory units should be encouraged to innovate. To under-score the importance of innovative industry strategies inthe conservation of water and in abating groundwaterpollution, a synthesis of experiences at the industry levelindicated substantial CP achievements in the hosieryindustry in terms of elimination of redundant processsteps, toxic substitution, water reuse and partial tech-nology upgradation. However, a much broader basedadoption of chemicals recovery, water conservation, andgreening of supply chains needs to be researched and

implemented in the coming years in order to make aquantum jump toward a sustainable hosiery industry.This will include:

O substitution of chemical dyeing by natural cotton col-ours;

O retrofitting winches (beck) with soft flow (jig) tech-nology;

O reconstitution and reuse of spent baths;O membrane separation application in recovering pro-

cess water and chemicals

Resource energy is another major-shared resource ofthe hosiery industry. Future CP studies in this sector arealso needed, with a focus on regional conservationopportunities and demand side management [30].

So far, uptake of CP solutions in the hosiery clusterhas been found to be predominantly supply-driven, dueto the efforts of major international and national insti-tutions.4 Market-led and quality cum efficiency-led CPlearning [31] have been gaining momentum within theindustry due to the advent of total quality environmentalmanagement system standards, such as ISO 14000 andeco-textiles guidance standards in the European markets.These developments further strengthen the linkage of CPexperiences with the consumption pattern of resourceefficient textile products [32] and might lead a movetowards value-led learning processes in the industry andsociety as a whole.

A great deal of CP education is still, however,required to encourage the regulators to shift the currentEOP regulatory regime5 towards one more CP focused.If regulation-driven learning is EOP oriented, then ittends to annul gains from CP learning. Therefore, inaddition to resource pricing, the key to rendering con-servation of shared resources ‘self-perpetuating’among the industry cluster, the urban and ruralenvironments, is to provide the regulators with inten-sive CP exposure.

Acknowledgements

Many thanks are due to the financial support and theactive participation provided by the hosiery industries ofTirupur and the local industry associations. Thanks also

4 Environment Division of National Productivity Council (NPC),India, National Cleaner Production Centre (NCPC), India, and Indus-trial Maturation Multiplier now known as Institute for Communicationand Analysis of Science and Technology (ICAST), Geneva, Switzer-land, are the major institutions.

5 Permits to operate are issued mainly based on the units’ demon-strated ability to install and operate pollution control equipments.Therefore, firm level CP efforts go unrewarded by the regulators. Thisis the most common frustration shared by almost all hosiery units thatparticipated in the CP study.


to the local governmental and non-governmental organ-isations who rendered information support to this studyand Mr Ashvin Parekh, the former Director(Management Consulting), KPMG India Private Lim-ited, Mumbai, who encouraged CP studies in the hosierysector, despite it being a low budget and non-profit con-sultancy engagement.

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[32] This is emphasised by Ralph Meima, The Consensus? — A dis-cussion of selected themes and conclusions from New Horizonsin Cleaner Production. In: Proceedings of the New Horizons inCleaner Production Invitational Brainstorming Seminar, Trolle-holm Castle, Sweden, October 22–23, 1997:74.

lessons from cleaner production experiences in indian hosiery clusters

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