ENERGY AND ENVIRONMENTAL INDICATORS IN THE THAI TEXTILE INDUSTRY

Transcription

1 524 ENERGY AND ENVIRONMENTAL INDICATORS IN THE THAI TEXTILE INDUSTRY C. VISVANATHAN, S. KUMAR, AND ARCHITRANDI PRIAMBODO Asian Institute of Technology, School of Environment, Resources and Development, PO Box 4, Klong Luang, Pathumthani 12120, Thailand Fax (66-2) S. VIGNESWARAN Faculty of Engineering, Environmental Engineering Group, University of Technology, Sydney, PO BOX 123 Broadway, NSW 2007 Australia. The textile industry is a major revenue generator, in many Asian countries, including Thailand. Negative impacts on the environment of textile industry are due to the discharge of pollutants and the of water and energy. However, the status of energy use and pollution generated in textile industry in Thailand is not known. This paper presents the results of a study undertaken to obtain the current status of energy and environmental parameters from textile manufacturing factories in Thailand, such as, specific energy cost, water, and wastewater load and its characteristics. The energy and environment status during along with other relevant information were obtained by means of a questionnaire survey, by visiting factories and from energy audit reports. The survey findings on energy show that range of specific fuel in spinning, weaving and printing mills are relatively narrow indicating that these factories consume fuel in a similar manner, while the variation is fairly large in other types of mills. The variation of fuel cost is found to be similar to that of the specific fuel. The water trend in various textile sectors shows that man-made fiber, weaving, and printing mills have a relatively low specific water as compared to other categories of mills. Similar observations were noted for the wastewater discharge. The data on wastewater characteristics after treatment, namely, biological oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solid (TSS) have also been presented. 1. Introduction The textile industry is one of the major contributors to many Asian economies and one of the main revenue-generating sectors. In Thailand, since the mid-eighties, textile and clothes have been the major export items. It is estimated that in , there were about 5000 textile mills in Thailand, of which eighty percent was in the small and medium scale industries category [4]. The share of the textile sector to the overall gross domestic product (GDP) increased from about 148 billion Baht in 1991 to about 240 billion Baht in The fraction of GDP from the textile sector to national GDP during has been relatively constant, at slightly above 5% [3]. The impacts on the environment by textile industry have been recognised for some time, both in terms of the discharge of pollutants and of the of water and energy. Many organisations have prepared guidelines for promoting energy efficiency and pollution prevention and control [6, 7, 8, 9, 10]. The current status of the energy use and pollution generated in the textile industry in Thailand is not available. A study was therefore initiated in 1999 to understand the energy and water, and wastewater generation in the various sectors of the textile industry by conducting a survey of these factories in the country. The results of this study are detailed in the following sections.

2 Methodology The survey was conducted by distributing questionnaires to about 200 textile factories in and around Bangkok. The questionnaire was structured to elicit information from the factories on: type of products, (yearly), energy (fuel and electricity), water, wastewater generated and their characteristics during three years ( ). Twenty two factories responsed to the questionnaire and field visits to some of these factories were arranged. Additional data on energy was obtained from energy audit reports based on energy audit conducted during by the Department of Energy Development and Promotion (DEDP) [1,2] for ten factories. The responses were then categorised into the various energy and environment indicators, namely, the specific fuel and electricity, specific fuel and electricity cost, specific water, specific wastewater generated and liquid effluents (BOD, COD and TSS). Table 1 summarises the relevant definitions of energy, water and pollution indicators used in the study. The textile establishments included manmade fibers, spinning, weaving, dyeing and finishing, integrated textile mills and printing factories. The survey was conducted over a period of about eight months. The data of the surveyed factories indicated that the responses had the following share of the total Thai textile (in 1997): 31% of all man-made fibers, 13.4 % of all fabrics; and 7.1 % of all yarns. This indicates that the survey covers a substantial share of the textile industries in Thailand. Energy and water 1. Specific fuel Yearly fuel /yearly 2. Specific fuel cost Yearly fuel cost/yearly 3. Specific electricity Yearly electricity /yearly 4. Specific electricity cost Yearly electricity cost/yearly Pollution 1. Specific wastewater generation Yearly wastewater generated /yearly 2. Liquid Effluent: BOD, COD and TSS: a. Liquid Effluent concentration (mg/l) b. Specific liquid effluent (kg/ton of 5. Specific water : Yearly water /yearly 3. Survey Results and Conclusion 3.1 Energy Table 2 gives the range of specific energy and specific energy cost, for both fuel and electricity based on the survey data and energy audit report of each factory in the

3 526 various sector along with their individual data. The dyeing and finishing mills were found to have the highest maximum specific fuel, followed by integrated textile mills. The printing, spinning and weaving mills have a very narrow range of specific fuel indicating that these factories consume energy in similar manner, while variation is fairly large in the other type of mills. The variation of fuel cost is found to be similar to the specific fuel range. The range of specific electricity in weaving mills observed from the survey is very small, at about MWh/ton of product while that of dyeing and finishing mills is quite significant, at about MWh/ton of product. This is also reflected in the range of specific electricity cost. The maximum specific electricity cost in printing, integrated and man-made fiber mills is about 2.5 to almost 5 times higher than the minimum, while in the spinning and the dyeing mills, it is about 15 to 27 times higher. Table 2. Specific energy and specific energy cost from survey of the Thai textile industry Category Specific fuel Specific fuel cost (GJ/ton of (Baht*/ton of Man-made fiber Spinning Weaving Dyeing and finishing Integrated mills *1 US$ = 37.4 Baht (July,1999) Specific electricity (MWh/ton of Water and wastewater generated Specific electricity cost (Baht/ton of Table 3 presents the range of specific water and specific wastewater generated estimated based on the survey. The dyeing and finishing mills were further classified according to type of products of the mills: yarn only, fabric only and yarn and fabric. The range of specific water depends on the type of establishments. The largest variation was found in dyeing and finishing mills ( m 3 /ton of followed by integrated, printing, and man-made fiber respectively. Man-made fiber, weaving and printing mills have relatively low specific water as compared to other categories of mills. For the weaving mill, for which data of only one factory is available, the specific water (10.3m 3 /ton of is within the range of the US EPA norms ( m 3 water consumed/ton of [8]. For dyeing and finishing mills, the specific water between the survey ( m 3 /ton of is, in general, within the norms ( m 3 /ton of [8]. For printing mills, the comparison with the norms established by NITRA [6] shows that the minimum and maximum specific water are lower than their guidelines ( m 3 /ton of.

4 527 The smallest range of specific wastewater generated is observed in man-made fiber mills at about m /ton of fiber. Establishments which have high maximum specific wastewater generated are the integrated textile mills at about m 3 /ton of product and dyeing and finishing sector at about m 3 /ton of product. The maximum specific wastewater generated in man-made fiber mills (at about 27.4 m 3 /ton of is much lower than the minimum value of WHO standard ( m 3 /ton of [10]. The maximum specific wastewater generated in integrated textile mills, at about 183 m 3 /ton of product, is lower than the WHO standard [10] which is 265 mvton of product. However, this observation may be valid only if these mills use cotton as the raw material. Compared with the standards given by the World Bank [9], the maximum specific wastewater generated in man-made fiber and printing mills (at about 27.4 and 8 m 3 /ton respectively) is lower than the minimum standard of 100 m 3 /ton of product. The wastewater generated from some integrated textile and dyeing and finishing mills is higher (about 10-15%) than that presented by World Bank [9]. Table 3. Specific water and specific wastewater generated from survey of Thai textile industry Category Man-made fiber Dyeing Yarn and Fabric finishing Yarn+Fabric Integrated mills 3.3 Liquid effluents after treatment Specific water (m 3 /ton of Specific wastewater generated (m 3 /ton of The liquid effluent data after treatment of some man-made fiber, dyeing and finishing integrated and printing mills are tabulated in Table 3. A comparison of the textile effluent and the standard for discharge of textile wastewater into receiving waters in Thailand shows that the liquid effluent after treatment in Thai textile sector is within the acceptable range of the effluent discharge standards. Table 3. Range of liquid effluent after treatment in Thai textile industry BOD COD TSS mg/l kg/ton mg/l kg/ton mg/l Type of 'mills Man-made fiber Dyeing and finishing Integrated textile mills Thai standard[5] kg/ton

5 528 Dyeing and finishing, and printing mills have higher values of BOD, COD and TSS level compared to other type of mills. The BOD level in dyeing and finishing mills varies significantly. The variation of BOD and COD level in Thai textile mills is within the acceptable range of the effluent discharge to receiving waters in Thailand [5]. The maximum value of BOD level in the printing mill is the same as that of the Thai standard. 4. Acknowledgement We are grateful to University Technology, Sydney (UTS) Australia, for sponsoring this work. We are also grateful to industries who participated in the survey Department of Industrial Promotion (DIP), Department of Energy Development and Promotion (DEDP) and Federation of Thai Industries who helped in conducting this study. Thanks are also expressed to the project "Small and Medium Scale Industries (SMIs) in Asia: Energy, Environment and Climate Interrelations" funded by Swedish International Development Co-operation Agency (Sida). References 1. Department of Energy Development and Promotion. Energy Audit Report of Thai Textile Industry 1996 (in Thai) ( Bangkok, Thailand, 1997;. 2. Department of Energy Development and Promotion. Energy Audit Report of Thai Textile Industry 1997 (in Thai) (Bangkok, Thailand, 1998). 3. Department of Industrial Promotion. Thai Textile Statistics 1997 (Bangkok, Thailand, 1998). 4. Federation of Thai Industries. Case study: Cleaner Technology, Project on Promotion of Cleaner Technology in Thai Industry (Bangkok, Thailand, 1998). 5. Ministry of Science, Technology and Environment. Laws and Standards on Pollution Control in Thailand, 4' h Edition (Bangkok, Thailand, 1997). 6. Northern India Textile Research Association (NITRA). Norms for the Textile Industry (Ghaizabad, India, 1989). On behalf of Textile Research Association at Bombay, Ahmadabad and Coimbatore, India. 7. United Nations Environment Programme (UNEP). The Textile Industry and the Environment (Paris, France, 1993) 8. US Environmental Protection Agency (US EPA). Development Document for Effluent Limitations Guidelines and Standards for Textile Mills, Environmental Pollution Control in Textile Processing Industry (Washington DC, USA, 1979). 9. World Bank. Pollution Prevention and Abatement Handbook-Part III, textile Industry (1998). 10. World Health Organization (WHO). Environmental Technology Series: Assessment of Sources of Air, Water and Land Pollution (Geneva, Switzerland, 1993).