Journal of Cleaner Production 6 (1998) 85-9 I

Starting continuous improvement with a cleaner production assessment in an Austrian textile mill

Johannes Fresner Stenum GmbH, Geidorfgiirtel 21, A-8010, Graz. Austria

Abstract .

This paper deals with the course and the results of a waste and emissions minimization project in an Austrian textile mill producing interlining fabrics. It was conducted within the Austrian PREPARE-project, which was designed to produce case studies in Austria to demonstrate the potential of the cleaner production approach to solve existing environmental problems of companies to our industry. The results proved the concept. In this mill, water use could be reduced by 30%, the COD of waste water by 30%, and 15% of the gas consumption of the dryers could be saved. The management stated at the end of the project early in 1993: “Suddenly we became aware of things we used to be blind to.” 1 . The project was only the beginning of a continuing process. 0 1998 Elsevier Science Ltd. All rights reserved.

Keywords: Cleaner production; Continuous improvement; Case study results; Textile industry

1. The initiative PREPARE

It was first in the USA that several large scale enterprises integrated preventive environmental protec- tion in their production processes, as a strategy of inno- vation for industry and commerce. In the early nineties, the Ministry of Economic Affairs in the Netherlands introduced PREPARE (Preventative Environmental Protection Approaches in Europe) as a research initiat- ive within Eurektiuroenviron. Since the focus was on main demands of innovative research, Austria has played a major role in this initiative right from the start. In 1990, a study-group was established on the initiative of the Federal Ministry of Science, Research and Arts, to pre- pare and coordinate PREPARE in Austria. First, stra- tegies for the implementation of pollution and waste pre- vention programmes were developed. Then the Federal Ministry of Science, Research and Arts joined up with the Federal Ministry of Environment to start the national PREPARE pilot project, and the “Printed Circuit Boards” Branch concept. Regional activities were started at the same time: the city of Graz was the first to start a communal programme called “ijkoprofit” [l].

2. The interlining fabrics mill and the method used in the project

The description of the project, in a textile mill produc- ing interlining fabrics, will illustrate the systematic approach to analysing the waste and emission minimiz- ation potentials of a company, and shows the measures which were implemented. The example is typical of the way in which over 30 companies have now been ana- lysed [2].

The company, Kufner Textilwerke in WeiBkirchen/Stmk. has 200 employees and an annual turnover of approximately US$40 million (1992). The Austrian plant is a subsidiary of an international group. The products include less expensive knitted interlining fabrics and fleeces, and interlining fabrics from natural goat and horse hair in a variety of about 200 articles which differ mainly in weight per unit area and finishing. Their main sales are natural hair interlining fabrics which go to the top clothing manufacturers of the world. High quality characterizes the products as well as methods of working and management. “Natural fibres deserve ecologically compatible production methods” was the statement made by the manager of the company at the start of the project.

The company mainly produces finished fabrics from

0959-6526/98/$19.00 0 1998 Elsevier Science Ltd. All rights reserved. PII: SO959-6526(97)00049-g

86 J. Fresner/Journal of Cleaner Production 6 (1998) 85-91

Spinning

4

+ Cutting

+

Shipment

Fig. 1. Flowsheet of the textile mill.

natural fibres in this mill. Therefore the production pro- cess includes dry processing as well as wet processing.

The processes include cleaning of goat hair, spinning, sizing, weaving, washing the fabrics (mainly for desizing and removing natural contamination), drying, dyeing part of the fabrics and finishing. A flowsheet is shown in Fig. 1.

Table 1 gives the process steps and their main emis- sions. The effluents from the mill are discharged into a publicly owned water treatment plant. The company holds a permit which allows them to release 300 kg/d COD. As production has increased continually, the com- pany exceeded this limit frequently. The waste water quantity was 200 m3/d when the project started in’ late 1992. One of the project’s aims for the company was to decrease the high chemical oxygen demand of the waste water. Additional problems were: high peak loads, foam- ing and intense colour of the waste water. These prob- lems had been addressed in earlier projects, mainly by trying to treat the total waste water stream physically in the plant.

Table 1 Process steps and characteristic emissions

Process step Waste or emission

Cleaning of hair Spinning

short fibres, dirt dust

Sizing waste water from equipment cleaning

Weaving

Washing

waste from cutting edges waste water with fibres, sizes and spinning oils

Knitting Dyeing Finishing Coating with adhesive Cutting

Yarn spent dyeing baths, washing water excess baths, dryer exhaust gas waste adhesive cutting waste

The method used in the project was described by Fresner [3]. It consists of the following steps:

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0

0

0

0

0

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Project organization Analysis of input and output of the company and the main processes Definition of problems Definition of priorities Collection of waste and emission prevention options Analysis of options Selection of viable solutions Realization of solution Feedback of success Presentation of results

The definition of problems is done by interpreting the flow of materials and energy and the efficiency of use. Also the criteria of legal compliance and toxicological relevance are applied. The setting of priorities was car- ried out in a joint discussion process between manage- ment and the consultants. Options are defined by study- ing relevant literature, benchmarking with data from comparable plants, where available, by contacting (potential) suppliers or simply by creativity within the project team.

One objective of the project was to demonstrate the potential of cleaner production to reduce waste and emis- sions and to reduce costs for the company at the same time. But equally important was the objective of implanting the knowledge and the ethic of pollution pre- vention into the company’s organization, which will lead to autonomous continuous improvement.

3. The course of the project

First of all, a comprehensive inventory of the materials used, energy consumed, products produced and the waste and emissions both to the public treatment works and the atmosphere was made for a business year. A one-day meeting with the management and the accountants of the company was conducted to determine the structure of the inventory, then data were collected, mostly using the accounting system of the company. The weight of the products was known from the quality sys- tem of the company.

To determine the composition of waste water and gaseous emissions, analysis of the processes had to be carried out: first, it was determined theoretically which substances went to the waste water and in what amounts by considering physical properties, operational practices and production schedules. Again, workshops with the management and the operators were conducted. Measurements of the single emission streams were then made to verify the theoretical analysis. The process of producing the first input/output analysis lasted for more than 6 months. The result is shown in simplified form in

Table 2 Input/output analysis for the textile mill

.I. Fresner/Joumal of Cleaner Production 6 (1998) 85-91

The inputs included: The outputs included:

Raw materials (goat and horse hair, cotton yarn, fleece) Auxiliary materials (size, lubricants, dyes, finishing materials, paste, packaging materials, greasing materials, repair materials) Energy (natural gas, electricity)

Products (finished fabrics, finished fleeces) Waste (contaminated hair, yam, reject product, containers, waste paste, waste fabrics) Waste water (carrying dirt, short fibres, natural greases, the sizes and lubricants and part of the dyes)

Air and water Gaseous emissions (from burning gas, etc.)

Table 2. The original table gives a detailed overview in kilograms and Austrian Schillings, of raw materials bought, amounts of water and air used and products, waste and emissions caused by the plant.

This inventory of masses and costs was done manually in the first run, which was a time-consuming process. But from the figures, which cannot be reproduced here, both the company and ourselves learned a lot: for example, the amount and composition of the waste and the waste water, and we defined efficiencies (ratio of material x in the products to material x purchased). These calculations are now done on a routine basis to illustrate the development and provide a controlling tool. So far, only estimations had been done, so there was no systematic mass balance.

Fig. 2 gives an overview of the material flows in the company. Raw and auxiliary materials account only for 3% of the total mass flows. Of the 3.100 t/a raw materials, 35% is hair, 58% yarns, and 7% fleece. The 800 t/a auxiliary materials consist of 6% sizes and spin- ning oils, 20% finishing chemicals, 6% dyes and dyeing chemicals and 68% adhesive paste. Most of the mass flows result from air (95% for drying and 5% for burning fuel) and from water (mainly for cleaning the fabrics).

Raw materials

Auxilliaries

Products

Waste water

96.0 97.0

Exhaust air/flue gases

Fig. 2. Overview of the material flows in the textile mill (including raw and auxiliary materials, water, and air) for 1992.

To our knowledge the product and the company are quite unique. There are only a few competitors world- wide. So it is difficult to obtain indicators for direct com- parision. To compare the use of water by this mill to other plants we use data from a BAT-study of the Euro- pean Commission [4]: according to this study, the water consumption for desizing in the textile industry in gen- eral can range from 2.5 to 210 l/kg fabric, for dyeing 17 to 25 (values for wool). In our mill, only a small percent- age of fabric is dyed. The main water consumption there- fore is for desizing. The average consumption in 1992 was 12 l/kg woven fabric. In the production of fleeces, very little water is used for cleaning.

The company has a high consumption of energy: it spent approximately US$l million for energy in 1992, 30% of this amount for natural gas. 50% of the gas was fired in the two directly heated stenters, the rest was con- sumed by the steam boiler.

The solid waste consisted of 25% reject product, 20% waste from trimming the edges, 30% contaminated hair, and 25% waste paste, scrap iron, and packaging materials. Approximately 3% of the input raw and auxiliary materials, mainly salts, sizes and spinning oils, were discharged into the waste water.

We evaluated these streams for their economical and environmental impact. Regarding economical value, the chemicals lost in the processes were arranged at the top. As regards the ecological impact, waste water and the emissions in it, the flue gases got priority.

Table 3 shows the priorities in this project and Fig. 3 the schedule.

Table 3 Priorities in the project

Priority

Input/output analysis Collection of process data: installment of meters, installment of laboratory, definition of procedures Waste water: reduction of waste water loads Stenter: Reduction of energy consumptions and emissions Solid waste: improved waste logistics, composition of contaminated hair Hazardous waste: fine filtration Electricity

88 J. Fresner/Journal of Cleaner Production 6 (1998) 85-91

Electricity

Solid waste

Waste water meaS”reme”tS

5 Stcnter

g waste water analysis Definition of priorities Input/output-analysis Preparations

1 2 3 4 5 6 7 8 9 1011 12 13 1415161718 19

Months (Marchl992-September 1993)

Fig. 3. Schedule of the project.

With this analysis to hand, we defined the priorities: the water supply and waste water system of the company was one area for more detailed work, the stenter and its gas consumption another, solid and hazardous waste the third and the consumption of electricity in general the last one.

During the second part of the project, we looked for options to reduce waste and emissions. As a result, water consumption was analysed in detail. The flow of water was traced through the processes, flow schemes were produced, and data collected describing the water con- sumption of each single machine independent of time and product. Similar work was done in respect of the other priorities. A good overview of cleaner production options in the textile industry can be taken from the UNEP technical report on the textile industry [5].

4. Results

The results of the project were: 10% of the process water could be saved by reusing cooling water as process water, 20% of water usage could be avoided by optimiz- ing the use of water through better process control, mainly in the washing process (e.g. switching off the water supply when the equipment is not used). Water is also saved by consequently applying the counterflow principle to the washing step: the fabrics are washed in two steps. The fresh water is added in the second step. The waste water from the first step is used to preclean the fabrics in the first step.

We also assessed the input materials for their ecologi- cal impact. For this, the suppliers were asked to produce data on the composition of, and ecological evaluations on, their materials. Most of them cooperated on an active basis. We also asked for the exact task of the material in the process, as well as its dosage.

The largest sources of COD in the waste water were identified: they turned out to be fibres, sizes, spinning oils, paste and finishing baths. Thirty per cent of the chemical oxygen demand in the waste water of the plant could be avoided: fibres and dust are now kept out of the water by vacuum cleaning the fabrics before washing

them and removing fibres from the waste water by a sieve. The solids can be landfilled.

The company now uses sizes and spinning oils which have a higher yield, a lower consumption and a better biodegradability.

Additionally, operational sequences have been par- tially changed to avoid wastes by frequently changing finishing baths: if it is possible, small lot sizes are avo- ided and a number of small lots is collected to form one big lot. The operators were trained to calculate the exact demand of chemicals to avoid bath rests. To optimize dosage and to avoid losses of chemicals, in 1995 an auto- matic dosage system for finishing chemicals was installed. This investment of US$200,000 is estimated to pay for itself within 2 years.

Adhesive paste, used to glue the interliners to the fab- rics in producing jackets, which is spilled during pro- duction or during the cleaning of equipment is recovered by filtering waste paste with a sieve and reusing it instead of disposing of it. This saves the company over US$lOO,OOO per year. Some components of the finishing baths are no longer used, because the quality of the fab- rics is acceptable without them. Others have been substi- tuted because of their high volability in the subsequent drying process. A basin for buffering the waste water was also built to eliminate peak loads for the publicly owned water treatment plant.

Wasted dyeing baths are reused once now in preparing new baths: Thus the emission of dyes is reduced by 50%. The accumulation of natural greases and of traces of spinning oils prevents a further reuse.

Peaks of COD are eliminated, the COD load of the primary effluent has been reduced by 30% in spite of the introduction of a fourth shift in weaving and fin- ishing, which are the waste water producing production steps. The BOD,, which used to be as low as 7-10% of the COD, is now well above 25%. There are no problems with acidic discharges any more, as they have been reduced by better scheduling and the remaining ones are neutralized in a new buffer basin by alkaline washing water. This basin is aerated to give some biological decomposition. The remaining total waste water is now fairly well degradable in the publicly owned waste water treatment plant.

To facilitate control of materials in the future, measur- ing devices for the determination of COD were bought and installed. Thus it could clearly be shown which sub- stances caused problems in the waste water and which did not. Monitoring systems for the use of fuel and auto- matic systems for the use of water were installed.

What impact do the changes in the company have on the waste water treatment plant? Table 4 gives the COD load of the effluent from 1991 to 1995 (measures taken during the project became effective in late 1993) from an evaluation made in July 1995.

Data for 1995 consider data from January to May. The

J. Fresner/Journal of Cleaner Production 6 (1998) 85-91 89

Table 4 COD load of the effluent from the waste water treatment plant

Year COD [mgll]

1991 74 1992 85 1993 103 1994 16 1995 60

light transmission of the effluent of the treatment plant, which used to be lower than 30 cm, is now well above 60cm [6].

Electricity was saved by frequency controlling blow- ers in the dryers and the air-conditioning system, and by changing the lighting system to a more energy efficient one.

Hazardous waste could be reduced by 60% by increas- ing the life time of hydraulic oils from 1 to 3 years by fine filtrating them with cellulose cartridges. The sup- plier of the fine filtrating equipment provides analyses of the oil to document the quality of the reprocessed hydraulic oils.

All in all, the company saved in total some US$200,000 by taking these measures, with a payback time of approximately 1.5 years. Another important out- come was that the need for an efficient quality manage- ment system was shown to reduce the amount of solid waste. Now, the company is preparing for IS0 9000 cer- tification.

Problems with the implementation of options arose from:

the need for time to test changes in recipes the need to keep production flexible due to quick responses to customers’ demands simultaneous time demand for quick and simple sol- utions steadily increasing production for plants that were built for much lower production, thus increasing the amount of sizes to facilitate weaving at higher velo- cities, and rising temperatures in the stenters to increase drying velocity

The company invested half a man year, as did the consultants. Many of the ideas for solving problems which had been addressed were initialized by the con- sultants and adapted to the surroundings and worked out by employees of the company. Again much work was done in small workshops, where we presented ideas for solutions to the operators and discussed with them their feasibility and developed a schedule for testing and implementation.

The work of the consultants was fully sponsored by the Austrian Ministries of Science and Youth, Environ- ment and Family, and the Innovation and Technology

Funds in this project. The figures given for the payback of the options do not include the work of the consultants and of the company during the project. The project was completed in the fall of 1993. Documentation of the pro- cess between 1994 and 1997 was done in an informal way, because both the company and the consultants were interested in exploiting the potential shown in the pro- ject. The company and the consultants still have a very good informal relation.

Two research projects resulted from this project (Table 5), which were conducted by the company after the end of the PREPARE-project together with the equipment suppliers.

One of these was to further minimize the use of water in the washing process by recycling the washing water. Experiments were carried out to clean it by ultrafiltr- ation, whereby the sizes could be recovered from the washing water. Tests with different types of membranes were conducted. The results were very promising, how- ever the suppliers did not give guarantees regarding cost and performance of equipment because of the complex compostition of this waste water stream (sizes, spinning oil, natural contamination from the hair). In principle it is possible to reduce the use of washing water by more than 50%, but at the moment investments and the risks involved are too high, regarding the unusually low local price for the sizes. As a result this option was not real- ized. Size recovery could become economically interest- ing only if production increases by roughly 300%, so this option was dropped.

The other project concerned the energy demand of the dryers which could be further reduced if the leakage of air through the inlet and outlet could be minimized (not the case with the present equipment (Table 5)). How- ever, the drying process was improved by vacuum removal of water and by introducing muffles to improve the control of the gas flow in the chambers of the stenter. This however cannot eliminate the formation of “blue haze”, so it was decided to install a gas washer in the near future. Table 6 gives an overview of the measures which resulted from the project.

5. Introduction of a quality management system (IS0 9000)

The installation of a laboratory, and the teamwork in the company have changed the knowledge of the environmental effects of the company completely. The controlling tools (input/output analysis, water meters) supply the company with the necessary information. There is now continuous control of the environmental impact. The company has become a reference, both for the suppliers and within its own group.

Today, they are elaborating a quality management system to decrease quality waste and further increase

90

Table 5

J. Fresner/Joumal of Cleaner Production 6 (1998) 85-91

Research projects resulting from the case study “inlay fabrics mill”

Title Description Aims Results

Optimization of washing process

Minimization of stenter emissions

Ultrafiltration and recycling of water in combination with possible substitution of sizes and optimization of existing equipment Improved control in combination with substitution of chemicals and optimization of equipment

75% reduction of water usage, 50% recycling of sizes

Elimination of “blue smog”, further reduction of energy consumption

Investment too high at the the moment. Recovery of water possible, at the moment not economical Further reduction in gas consumption, limited by air leaks, which cannot be avoided with present equipment

Table 6 Selected measures resulting from the project and their results

Year

1993 1993

1001 1//J

1993

Measure Result

Control of water in washing mashine - 20% water use, no relevant cost Reuse of cooling water as process water - 10% water use, no relevant cost Installment of vacuum cleaner and rotary sieve to keep solids out

- 30% COD of washing water Changing operational sequences in finishing less wasted finishing bath rests, no relevant cost

contributes to less COD in waste water and saves several US$lO,OOO a year, no relevant cost lower emissions of hydrocarbons to the exhaust fumes, hardly quantifiable

1993 Filtering of spilled paste

1993 Substitution of components of finishing bath

1993

1993

1993

1993-1996

1993 1994 1994 1994 1995

1995 1995 1996 1996

Changing lighting system

Fine filtration of gear and hydraulic oils

Frequency control of blowers

Better waste logistics, compostation of dust and dirt, external recycling of textile waste Installation of a waste water buffer basin Reuse of spent dye bath Installation of own laboratory Input/output analysis as controlling tool Modification of burners in stenter First drying step by vacuum removal of water Dosage system for finishing chemicals Voluntary emissions report Introduction of quality management system Open Day

- 30% electricity for lighting in certain areas, payback 2 years - 60% hazardous waste, payback 2 years

less electricity, - 15% gas consumption in dryers, payback 1 year

- 75% industrial waste (quality domestic waste)

elimination of peaks - 50% colour in waste water

not yet quantified

annual savings of US$lOO,OOO, payback 2 years

productivity. After the certification according to IS0 9001 the next step will be to include environmental responsibilities into the management system and to develop the documentation necessary for certification according to IS0 14001. For this project, the main task is the formal description of an already existing, living environmental management system. Participation in EMAS is also planned in the near future.

6. Clbnciusions

consumption of raw materials, water and energy. The installed electronic data processing is primarily working on a material balance and improves the flow of infor- mation. Their own laboratory now allows the study of new raw materials, a steady control and washing, dyeing and finishing experiments: measures that pay off econ- omically as well as ecologically. Also the communi- cation of the management with me authorities has changed fundamentally: the company now keeps a rec- ord of the daily water consumption, waste water and its COD and supplies the local authorities with a monthly report.

To cite the management at the end of the project: Cleaner production has the potential to save 0.5-1.5% “Suddenly we became aware of things we used to be of the total costs of producing companies by investments blind to”. Today there is regular feedback of the actual paying back according to present economical standards.

J. Fresner/Jounal qf Cleaner Production 6 (1998) 85-91 91

This correlates well with the findings of the Deutsche Bundesstiftung Umwelt [7]. This potential looks low in comparison to the turnover, but in relation to the net profit, it substantially adds to the companies financial performance. However it takes a methodological approach and creative questioning of daily practice to make the potential transparent. Not all problems could be solved with cleaner production approaches only. For the cleaning of the remaining flue gases and the waste water, end of pipe technology was employed. But it was clearly conceived that it is more sound to prevent as much pollution as possible. The realization of the cleaner production potential can take its time. Cleaner pro- duction works best if it becomes a continuous improve- ment process, supported by backup from external con- sultants and the authorities.

Acknowledgements

Special thanks are due to the project team: Dr Hans Schnitzer, Dr Kurt Schauer, Wilhelm Zapfel and Max Unterweger, as well as the sponsors: Michael Paula, Fed-

eral Secretariate of Science and Research, Andreas Tschulik, Federal Secretariate of Youth, Environment and Family, and the Innovation and Technology Funds (ITF).

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