POLLUTION MINIMIZATION AND ENERGY SAVING POTENTIALS IN THE COTTON DYEING INDUSTRY

by

Sanga Tubtimhin A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science. Examination Committee: Prof. C. Visvanathan (Chairman) Dr. P. H. Nielsen Dr. S. Kumar Nationality: Thai Previous Degree: Bachelor of Science (Public Health)

Khon Kaen University, Thailand

Scholarship Donor: Cleaner Production for Industrial Efficiency in Samut Prakarn Project (CPIE)

Asian Institute of Technology School of Environment, Resources and Development

Thailand April 2002

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Acknowledgements

The author wishes to express a profound gratitude and sincere appreciation to his

adviser, Prof. C. Visvanathan, for his supervision, guidance and encouragement throughout this study.

Sincere appreciation is also conveyed to Dr. S. Kumar and Dr. P. H. Nielsen as the committee members, for their helpful comments and suggestions.

The author is thankful to research site management, specially to Mr. Peerasich Kasemchaipipat, Mr. Apinun Tomeechai, Mr. Pitak Kitsakom, Ms. Chureeporn Tongpare and all staff in the factory for their support, complete faith, trust, and guidance given throughout the project.

Acknowledgements are also due to CPIE and PCD, his scholarship donor for giving him an opportunity to study at AIT and making this thesis a possibility.

Due recognition is also given to all UEEM staff members, for their assistance and cooperation during the course of this study and experiment.

Sincere thanks are given to Ms. Panit Rattasuk, Mr. Boonchai Wichitsathian, Mr. Nguyen Le Troung, Mr. Parinya Boonkasem, and other friends for their suggestions and helping for successful completion of this study.

Finally, deep appreciation and thanks are given to his family for their constant love, support and encouragement.

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Abstract

This study was conducted to identify the pollution minimization and energy saving potentials in the cotton dyeing industry. This factory produces bath towel with a capacity of 789 tons per year and now facing with many environmental problems.

Eco-mapping was adopted to identify the environmental problems within this factory. As a result, four major problems were identified, there are wastewater treatment, noise pollution, cotton dust control and energy saving. After conducting a waste audit, the option for waste and energy minimization were identified and recommended.

Wastewater generated from dyeing process around 342 m3/day is generally combined and sent to wastewater treatment plant (WWTP). This study recommended the segregation between less polluted and highly polluted wastewater. The result presents 127 m3/day of wastewater can be reused or directly discharged to public canal as well as the reduction of wastewater quantity that sent to WWTP.

Wastewater treatment study was done for combined and segregated wastewater using ferrous sulfate, ferrous sulfate with lime and alum. Results of the treatment study revealed that alum gave better COD and color reduction in both conditions.

Water pinch analysis was used as a guide for water and effluent management. The

result presents 88 m3/day of wastewater can be reused in the internal dyeing processes. That means 88 m3/day of freshwater is saved too.

Airborne particulate matter (total dust) in the plant was found to be less than

standard of Thailand. However, the management of cotton dust should be considered. Noise level measured in the weaving section was found to be higher than standard level (90 dB (A)).

Energy conservation potentials were examined for saving the heat loss. The result shows that insulated pipe and tank can save energy 62 % of the heat loss through pipes.

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Table of Contents Chapter Title Page Title page Acknowledgement i Abstract ii

Table of Contents iii List of Figures vii List of Tables viii

List of Abbreviations x

1 Introduction 1.1 General 1 1.2 Objectives 2 1.3 Scope of the study 2

2 Literature Review 2.1 Introduction of Textile Industry 3

2.1.1 Dyeing Process 4 2.1.2 Dyeing Methods 5 2.2 Water Quality for Textiles Industry 5 2.3 Water Consumption 6 2.4 Sources of Wastewater and Its Characteristic 6 2.5 Wastewater Treatment 9 2.6 Waste Audit 10 2.7 Waste Minimization 10 2.8 Wastewater Minimization 14 2.9 Segregation of Wastewater 17 2.10 Water Pinch Analysis 17

3 Background Information of the Research Site 3.1 General Background 19 3.2 Production Processes 19 3.3 Organization and Production Activity Schedule 20 3.4 Environmental Problems Issues of the Factory 20

3.5 Water Consumption and Treatment 26 3.6 Energy Consumption 26 3.7 Solid Waste Management 26 3.8 Chemical Consumption 27

3.9 Wastewater Treatment Plant 27 3.10 Wastewater Characteristic 27

4 Methodology

4.1 General Study Program 30 4.2 Waste Audit Studies 30

4.2.1 Water Supply and Distribution System 30 4.2.2 Water Consumption Measurement 30 4.2.3 Sampling Methods 30

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4.2.4 Wastewater Flow Measurement 34 4.2.5 Water and Wastewater Analysis 34 4.2.6 Mass and Water Balance 35

4.3 Air and Noise Pollution in the Workplace 35 4.3.1 Airborne particulate matter measurement 35 4.3.2 Noise measurement 35

4.4 Wastewater Segregation Study 39 4.5 Wastewater Treatment Plant Study 39 4.6 Water Pinch Analysis 39 4.7 Wastewater Minimization Options 39

4.8 Economical Feasibility Analysis 39

5 Results and Discussion 5.1 Plant Walkthrough Audit 40 5.1.1 Questionnaires 40 5.1.2 Eco-mapping 40 5.2 Material Consumption and Wastewater Generation 47 5.2.1 Raw Material Consumption 47 5.2.2 Water Consumption 47 5.2.3 Energy Consumption 50 5.2.4 Chemical Consumption 50 5.2.5 Material and Water Balance 50 5.2.6 Wastewater Flow Measurement 52 5.2.7 Wastewater Characteristic 53 5.3 Wastewater Segregation 54 5.3.1 Current Status of Segregation 54 5.3.2 Proposal for Better Wastewater Segregation 54 5.4 Wastewater Quantity and Treatment Plant Efficiency 54 5.4.1 Proposed Modifications for WWTP 56 5.4.2 Coagulation Dosage and Settleable

Determination 57 5.5 Air and Noise Pollution in the Workplace 60 5.5.1 Airborne Particulate Matter 60 5.5.2 Noise Measurement 61 5.6 Chemical Substitution 63 5.7 Energy Audit and Heat Loss 64 5.7.1 Boiler Efficiency 64 5.7.2 Energy Conservation 64 5.8 Water Pinch Analysis 65 5.9 Wastewater Minimization Options 68 5.10 Economical Feasibility Evaluation 69

6 Conclusion and Recommendations

6.1 Waste Audit in Plant 70 6.1.1) Water and Wastewater Minimization 70 6.1.2) Energy Conservation 70 6.1.3) Noise and Dust Control 70 6.2 Wastewater Treatment Plant 71 6.3 Water Pinch Analysis 71 6.4 Recommendations for Further Studies 71

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References 72 Appendix A Data Information from the Factory 74 Appendix B Water and Wastewater Characteristic 81 Appendix C Standard and Recommendations 87 Appendix D Experimental Data 90 Appendix E Heat Loss Calculation 97 Appendix F Economical Feasibility Analysis for Waste Minimization 102

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List of Figure

Figure Title Page 2.1 The Basic Production Process of Textile Industry 3 2.2 Dyeing Wastewater Treatment 11 2.3 A Waste Audit Plan 12 2.4 Waste Minimization Techniques 13 2.5 Water Minimization through (a) Reuse, (b) Regeneration Reuse,

and (c) Regeneration Recycle 14 3.1 Location of the Factory 21 3.2 Plant Layout of the Factory 22 3.3 Flow Chart of General Production Processes 23 3.4 Flow Diagram of Production Processes 24 3.5 Cotton Fabric Dyeing Process 25 3.6 Raw Water Treatment and Distribution 26 3.7 Diagram of Wastewater Treatment Plant 29 4.1 General Methodology Outline 31 4.2 Sampling Point of Dyeing Processes 32 4.3 Sampling Point of Wastewater Treatment Plant 33 4.4 Bucket and Stopwatch Measurement 34 4.5 Airborne Particulate Sampling Equipment 36 4.6 The Integrated Sound Pressure Level Meter 36 4.7 Airborne Particulate Sampling Points 37 4.8 Noise Sampling Points 38 5.1 Surrounding Environment 42 5.2 Eco-map of Water and Wastewater 43 5.3 Eco-map of Energy 44 5.4 Eco-map of Noise and Dust 45 5.5 Eco-map of Solid Waste 46 5.6 Distribution of Water Use in the Factory 47 5.7 Overall Water Consumption 48 5.8 Trend of Monthly Consumption (a) Groundwater (b) Fuel Oil (c) Electricity 5.9 Material Balance in Dyeing Process 51 5.10 Overall Water Balance 51 5.11 Estimate Daily Wastewater Flow rate from Dyeing Processes 52 5.12 Variation of Wastewater Flow rate 53 5.13 Schematic Diagram of Proposed Stream Segregation in Dyeing Process 55 5.14 Removal Efficiency of BOD, COD, SS and color of the WWTP 56 5.15 a) Present Flow Diagram of WWTP b) Proposed Modification of WWTP 58 5.16 Jar Test Result Using Alum for Combined Wastewater 59 5.17 Jar Test Result Using Alum for Wastewater after Segregation 59 5.18 Sampling Points Location and Noise Level in the Factory 62 5.19 Initial Result of three groups from Matlab Program 66 5.20 Result of All for Three Groups 66 5.21 Proposed Water Reuse Scheme in Batch Type of Dyeing Process 67 A-1 Organization Management of the Factory 75 E-1 Released Heat from Bare Pipe 101

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List of Tables Table Title Page 2.1 Maximum Permissible Concentrations in High-Quality Water for

Textile Industry 5 2.2 Comparison of Specific Water Consumption in the Thai Textile Industry 6 2.3 Dyes for Cotton Yarn Dyeing and the Compositions of the Wastewater 7 2.4 Wastewater Characteristic of each Cotton Processing 8 2.5 Typical Compilation of Discharge Standards in Several Countries for 8

The Textile Industry 3.1 Solid Waste Management in the Factory 27 3.2 Range of Wastewater Characteristics of Factory ( Jan.-June, 2001) 28 4.1 Analytical Parameter, Location and Methods 34 5.1 Summary of Environmental Management Questionnaires 41 5.2 Daily Average Amount of Water Used that was compared With Standard of Thailand and US EPA Data 48 5.3 Comparison of Energy Consumption with Standard of Thailand and UNIDO 50 5.4 Comparison of Wastewater Generation to Standard of Thailand, WHO and World Bank 52 5.5 Average of Wastewater Flow rate 53 5.6 Comparison of Wastewater Treatment Cost With and Without Stream Segregation 60 5.7 Concentration of Airborne Particulate Matter of Various Areas 61 5.8 Substitution of Chemical and Advantage 63 5.9 Heat Loss from Not insulated and Insulated of Pipes and Tanks 64 5.10 Initial Input Data for Dyeing Process 65 5.11 Group Data Classifying 65 5.12 Wastewater Minimization Options 68 5.13 Economical Feasibility Evaluation for Wastewater Minimization Measure with Payback Period 69 A-1 Raw material, Water, Energy and Products in 2001 76 A-2 Material Input per Batch for Dyeing Machine 77 A-3 Water and Chemicals used in Dyeing Machine per Batch 78 A-4 Estimate Chemicals Consumption in Production Processes 79 A-5 The Production Activity Schedule of the Factory 80 B-1 Wastewater Analysis Results (05/10/2001) 82 B-2 Wastewater Analysis Results (26/11/2001) 82 B-3 Wastewater Flow Rate Measurement (05/10/2001) 83 B-4 Wastewater Flow Rate Measurement (10/10/2001) 83 B-5 Wastewater Flow Rate Measurement (25/10/2001) 84 B-6 Wastewater Analysis Results of WWTP (27/09/2001) 85 B-7 Wastewater Analysis Results of WWTP (26/11/2001) 85 B-8 Water Quality of the Factory (26/01/2002) 86 B-9 Water Supply Record 86 C-1 Industrial Effluent Standards in Thailand 88 C-2 Noise Level Standard in Workplace 89 D-1 Jar Test Result using Ferrous Sulfate for Combined Wastewater 91

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D-2 Jar Test Result using Ferrous Sulfate for Wastewater after Segregation 91 D-3 Jar Test Result using Ferrous Sulfate and Lime for Combined

Wastewater 92 D-4 Jar Test Result using Ferrous Sulfate and Lime for Wastewater after Segregation 92 D-5 Jar Test Result using Alum for Combined Wastewater 93 D-6 Jar Test Result using Alum for Wastewater after segregation 93 D-7 Sludge Dewaterbility 94 D-8 Concentration of Airborne Particulate Matter of Various Areas 95 D-9 Noise Level of Various Areas 96 F-1 Costing Details of Water Reused System 103 F-2 Costing Details of High Pressure Cleaning System 103 F-3 Costing Details of Energy Conservation 104

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List of Abbreviations ADMI American Dye Manufactures Institute AIT Asian Institute of Technology BAT Best Available Technique BMR Bangkok Metropolitan Region BOD Biological Oxygen Demand CPIE Cleaner Production for Industrial Efficiency in Samut

Prakarn Province COD Chemical Oxygen Demand EPA Environmental Protection Agency GAC Granular Activated Carbon GEC Global Environment Center Foundation GDP Gross Domestic Product hr Hour IPPC Integrated Pollution Prevention and Control kg Kilogram kg/d Kilogram per day kWh Kilo Watt hour L Liter m3 Cubic meter mg Milligram m3/d Cubic meter per day mm Millimeter MOSTE Ministry of Science, Technology and Environment MWA Metropolitan Waterworks Authority NC DEHNR North Carolina Department of Environment, Health, and

Natural Resources NITRA Northern India Textile Research Association NTU Nessler Turbidity Unit PCD Pollution Control Department pH Acidity or alkalinity of a solution PVA Polyvinyl alcohol SS Suspended Solid TDS Total Dissolve Solid Temp Temperature TSS Total Suspended Solid UNEP/IEO United Nations Environment Programme/ Industry and Environment office UNIDO United Nations Industrial Development Organization US EPA United States Environmental Protection Agency UTS University of Technology, Sydney Australia WHO World Health Organization WW Wastewater WWTP Wastewater Treatment Plant yr. Year

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Chapter 1

Introduction 1.1 General

Samut Parkarn province is located on the coast of the upper Gulf of Thailand. This is one of five provinces of the Bangkok Metropolitan Region (BMR), on south and southeast of Bangkok. About half of the province’s land is still agricultural, mainly for fish and shrimp ponds along the coast. There is also some rice and vegetable farming. Part of the coastline still has a narrow strip of mangrove forest. But the proximity to Bangkok and the Chao Phraya River have made the province is best location for Thailand’s industrial development.

Cleaner Production for Industrial Efficiency in Samut Prakarn Province (CPIE, 1998) study reported, that in 1993, Samut Prakarn had 5,356 registered factories and 462,640 workers. The majority of industries are textile, dyeing and steel. While industry has expanded throughout the province, Samut Prakarn faces a range of environmental management problems: water pollution, air pollution, noise pollution, solid and hazardous wastes, as well as health and safety. These problems are generally caused by the rapid and unplanned expansion of population and industries, lack of zoning and area planing, inadequate public utilities, and lack of control of disposal of municipal and industrial wastes.

The textile industry is one of the largest industries in Samut Prakarn Province. It is classified into cotton, wool, and synthetic fiber sectors. There are consumed high quantities of water and produced large volumes of wastewater. Major pollutants are high SS, TDS, BOD, COD, pH and color. The main source of wastewater comes from dyeing process. End of pipe treatment is widely used to overcome the pollution problem in textile industry. The pretreatment, coloration, and after treatment usually require a large amount of water and a variety of chemicals. The pollution problems associated with these processes are caused by discharge of untreated effluents.

Water is often thought of as a free resource because of its relatively low cost. However, it is not free, and when used in large quantities, the cost can add up. The potable water used in most industrial process is a resource that should be limited. Another significant factor is the cost of treating the contaminated wastewater. Wastewater treatment is expensive, and cost increases as the volume of water to be treated increases. If the water becomes contaminated with hazardous materials, the cost can be increased too. Therefore, resource conservation is essential that water use be minimized to avoid costs associated with its treatment (Bishop, 2000).

Wastewater minimization is a method for conserving water and also reducing the

wastewater generation. It focuses on practices that reduce the wastewater in factories, at source and increase efficiency in the use of water. There are four general approaches to wastewater minimization; process change, water reuse, regeneration reuse and regeneration recycle (Wang and Smith, 1994). Process changes usually involve some combination of modifications of equipment or technology, process or procedure modifications, reformulation or redesign of products, substitution of raw materials and improvements in

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housekeeping, improved maintenance, training, and inventory control. There are three main ways of water reuse can be used, 1) internal wastewater recycling, 2) reuse of treated industrial wastewater in the same process and 3) reuse for other activities such as irrigation, fire protection etc. (Visvanathan, 2001).

The selected factory is a textile industry located in Samut Prakarn Province. Water

supply for these industries come from two sources, groundwater wells and water supply from Metropolitan Waterworks Authority (MWA). This factory consumed high volume of water and therefore generated large amount of wastewater. The effluents are generally colored, have high BOD, high SS, high TDS, and high pH. Sometimes it may containe toxic chemicals as well. Therefore, reducing of water consumption and minimizing of wastewater are necessary to adopt for decreasing the environmental problems and treatment cost. 1.2 Objectives

1) To study the manufacturing processes of textile industries. 2) To conduct a waste audit of the production process to identify the pollution and

energy problems.

3) To evaluate the present status of wastewater treatments plant and suggest for its possible improvement.

4) To identify the possible approaches for minimizing of waste generation and

energy consumption.

1.3 Scope of the Study

This study was conducted in one selected factory and covered all process, including wastewater treatment plant. Waste audit was conducted on water and energy consumption and also wastewater generation. Waste minimization and energy saving focused on the production processes in the factory.

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Chapter 2

Literature Review 2.1 Introduction of Textile Industry

Textile means any product derived from the manufacture of natural fibers such as wool, cotton, flax and the manufacture of fibers synthesized and processed from petrochemicals and modified wood pulp such as polyester, nylon, polypropylene and viscose. These products can be yarns, fabrics or consumer products.

Textile processing means the preparation of natural, and man-made (semi-natural

and synthetic) fibers. There are including both (i) the mechanical processes such as carding, spinning, weaving, knitting or tufting and (ii) the physico-chemical process which mainly take place in aqueous media, such as the pretreatment, the coloring and the finishing of the fibers, yarns and fabrics. The basic production processes of a textile industry are shown in Figure 2.1.

Raw Cotton Products

Cleaning Carding

Weaving

Sizing Warping Spinning

Desizing

Mercerizing Finishing Dyeing

Scouring Bleaching

Receiving Drawing

Roving

Figure 2.1 The Basic Production Processes of Textile Industry (Hussian, 1994)

Brief descriptions of each process as follows:

1) Receiving: Raw material is received in form of highly compressed mass of entangled cotton fibers containing different sizes of fibers and natural impurities. This is known as “Ginned Cotton”.

2) Cleaning: The bales of raw fibers (cotton) are opened and removal of trash, seed,

dirt and short fibber and uniform product in a suitable form to the next stage.

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3) Carding: During carding, the machine removes most of the remaining impurities from the cotton as well as relatively short fibers. This process is cleaning and attenuating a lap of fibers to a sliver by the combing motion of the carding machine.

4) Drawing: The draw frame draws several slivers from the card and attenuates them to

the dimension of one thus increasing the uniformity of the product.

5) Roving: The roving frame is further to attenuate the actual drawing, twisting it slightly in order to provide strength and to wind it onto bobbins suitable for spinning. This process is eliminated in open-end spinning.

6) Spinning: In spinning, fibers are drawn out into yarn and a twist is introduced. The yarn is used ether as wrap (longitudinal threads) or weft (inserted into the wrap threads) to produce cloth by the weaving processes.

7) Warping: The warping is to prepare a package suitable to feed the subsequent process of slashing. During warping about 500 parallel yarns are wound onto a back beam.

8) Sizing (Slashing): Sizing is the process of sizing warp yarns on a slasher to protect the yarn against injury during weaving. The sizing strengths the yarn and reduces the hairiness of the threads. Typical sizing agents are starches, starch ether, polyacrylate, polyvinyl alcohol (PVA) and carboxymethyl cellulose.

9) Weaving: Weaving is a dry operation that helps to minimize yarn breaks on the loom, as the size film is flexible. After inspection for faults the grey cloth is cropped and singed to remove any surface hairiness.

10) Desizing: To remove the substance applied to the yarns to impart tensile strength in the sizing operation. There are two methods; acid desizing and enzyme desizing. After the size has been solubilized, the fabric is rinsed clean in hot water.

11) Scouring: To remove the natural and acquired impurities from fibers and fabric.

Scouring agents include detergents, soaps, alkalis, wetting agents, foamers, and lubricants. 12) Bleaching: Bleaching is used to remove the natural yellowish coloring of the cotton

fiber and renders it white. The three bleaching agents most commonly used are sodium hypochlorite, hydrogen peroxide and sodium chlorite. The final rinse may contain an antichlor, sodium bisulfite or sulfuric acid, to remove residual chlorine from the fabric.

13) Mercerizing: Mercerizing is used to increase the water absorbency of cotton, to

impart brightness, to increase dye affinity, and tensile strength. 14) Dyeing: The dyeing process is carried out in an aqueous bath with pH variations of

6 to 12. Dyes used by the textile industry are classified according to application, e.g. acid dyes, direct dyes, basic dyes, disperse dyes, mordent dyes, pre-metallised dyes, reactive dyes, sulphur dyes, vat dyes.

15) Finishing: A final size or resin is applied to impart a smooth appearance and stiffness. Special treatments such as heat proofing, etc. are also done something.

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16) Printing: Printing is used to impart a color pattern or design to the cloth. The cloth is passed over a roller print machine. After printing, the cloth is steamed and treated to fix the color

2.1.1 Dyeing Process

The dyeing of cloth is carried out in a variety of ways. Natural organic colors of vegetable origin, a number of synthetic dyes known as coal tar dyes, dyes of mineral of inorganic origin and many auxiliary chemicals are used in the dyeing operations. The large variety of chemicals used in these operations adds to the complexity of the processes. In an attempt to make more attractive and popular shades of colored cloth in a competitive market, every industry uses its own refined techniques with the result that the processes used vary from industry to industry. However, dyes loading vary widely, depending on the weight of fabrics being treated and the depth of color desired. Dyed cloths are generally washed and rinsed to remove excess dye and chemicals. Color is an obvious waste. Due to the need for auxiliary chemicals in most dyeing operations, a number of compounds may contaminate in wastewater (Hussain, 1994).

2.1.2 Dyeing Methods Dyeing methods is main process cause of wastewater in textile industry, which can be divided in two types as follows (Paopuree, 1996).

1) Batch wise or discontinuous method that includes all dyeing processes wherein dyestuff is exhausted from a quantity of water relatively large in proportion to the material to be dyed. It varies according to method of dyeing. There are many types of the dyeing machines such as Jiggers, Winches, and Jet.

2) Continuous methods are mainly used in the dyeing of textile fibers when they are

woven into cloth. The fabric is uniformly impregnated with the required amount of dyestuff and other necessary chemicals by a process called “padding”. This consists of a rapid passage of the fabric at full width through a solution or suspension of dyestuff, thus loosely applied to the fabric, is then fixed usually after intermediate drying, by passage through statement of hot air. It is at this stage the dye diffuses into the fabric interior. A “soaping” treatment to remove unfixed dyestuff, and with certain dyestuff types, to develop true color and fastness, completes the process. 2.2 Water Quality for Textiles Industry

Barclay and Buckley (1998) explained that the textile industries require water of potable or higher quality for production process as shown in Table 2.1. Table 2.1 Maximum Permissible Concentrations in High-quality Water for Textile Industry

Parameter Unit Range Color (platinum) Hardness as CaCO3Turbidity (SiO2)

- mg/L mg/L

0-20 0-20 3-27

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Iron (Fe) Manganese (Mn) Fe & Mn

mg/L mg/L mg/L

0.1-1.0 0.05-1.0 0.05-1.0

Source: Barclay and Buckley (1998) 2.3 Water Consumption

Kumar et al., (1999) studied the water consumption trend in the various textile sectors in Thailand that man-made fiber, weaving and printing mills have relatively low specific water consumption as compared with US EPA (1979) and NITRA (1989) data.

Table 2.2 shows the specific water consumption in the different establishments along with the available standards from US EPA (1979) and NITRA (1989). Table 2.2 Comparison of Specific Water Consumption in the Thai Textile Industry with US EPA (1979) and NITR (1989) data.

Water consumptionc (m3/ton of product)

Standard (m3/ton of product)

Type of Establishment

Min Max Min Max Man-made fiber 4.4 30.7 - -

Fabric making (dry processing)* 10.3 0.8a 140.1a

Dyeing and finishing • Yarn • Fabric • Yarn + Fabric

114.8 125 73.1

180 160

166.7

3.3a

5a + -

557.1a

507.9a ++ -

Integrated textile**mills (all fabric) 107.7 183.3 - - Printing 11.9 62.4 40bx 100bxx

Source: aUS EPA (1979), bNITRA (1989), cfrom survey Based on information from mills that responded to the questionnaires: * One factory data only ** The process requiring water in these mills is dyeing and finishing only and the dyed material is only

fabric From the available standard: + The lowest minimum value of water consumed in woven fabric finishing process ++ The highest maximum value of water consumed in woven fabric finishing process x Water consumption for pigment printing xx Water consumption for washing printing 2.4 Sources of Wastewater and Its Characteristic

Sources of wastewater in the textile industry are generated from wet processes, which include sizing, desizing, scouring, bleaching, mercerizing, dyeing and printing. Each process produces a waste with different characteristics and varies in strength, flow, and composition.

Sizing wastewater results from the cleaning of sizing boxes, rolls, size mixer, sizing

area and the drainage of sizing solution. Their volume is low but, depending on the recipe used, can contain high levels of BOD, COD and TSS.

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Desizing effluent results from additives used in the size technique, surfactants,

enzymes, and acids or alkaline as well as the sizes themselves. The generated wastewater can be the largest contributor to the BOD and TSS.

Scouring wastewater characteristic is an organic and alkaline, contain fabric

fragment starch and sizing materials, caustic soda and chemicals used. It generates very high BOD concentrations.

Bleaching wastewater usually has high solids content with low to moderate BOD

levels include alkaline and contain bleaching agents. Mercerizing wastewater has low BOD and total solids levels but are highly alkaline

prior to neutralization. The low BOD content arises from surfactants and penetrating agents used as auxiliary chemicals.

Dyeing wastewater depend upon the dyes used. It contributes high volume, color, low BOD, high COD, high temperature and is sometimes toxic (Hussain, 1994; Correia et al., 1994).

Many types of materials and chemicals are used for dyeing. When the wastes of these materials are discharged, they can produce polluted wastewater of various forms, such as stain, pH, BOD, and COD as well as contents of nitrogen, phosphorus and hazardous substances. Organic materials used to process textiles are biochemical hard to decompose as they are used to prevent discoloration of finished products. Therefore, wastewater is often non-degradable (Honda and Yamamoto, 2000). There are six important classes of dyes used on cotton dyeing process that is shown in Table 2.3

Table 2.3 Dyes for Cotton Yarn Dyeing and the Compositions of the Wastewater

Type of dye

The compositions of the wastewater

Reactive dye

Dye, caustic soda, soda ash, interfacial active agent, salt cake

Developed dye Dye, sodium chloride, sodium nitrate, penetrant, sodium sulfide, chlorine or sulfate, developer (B-Naphthol), interfacial active agent, soap or sulfated soap or fatty alcohol.

Direct dye

Dye, sodium carbonate, salt or salt cake, interfacial active agent, Sodium sulfate.

Naphthol dye

Dye, caustic soda, interfacial active agent, alcohol, soap, soda ash, salt, bases, sodium acetic, sodium sulfide, sodium nitrate, sodium nitrite.

Sulfide dye

Dye, sodium sulfide, sodium carbonate, salt

Vat dye

Dye, caustic soda, interfacial active agent, sodium hydrosulfite, potassium dichromate, perborate or hydrogen peroxide

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Source: Honda and Yamamoto (2000)

Textile effluents are generally grey in pretreatment processes or colored in

coloration processes have a high BOD and COD, have solids and a high temperature as well as alkalinity, oil and possibly toxic organic, including phenols (from dyeing and finishing) and halogented organic (from bleaching). Dye wastewater is frequently highly colored and may contain heavy metal such as copper and chromium. Pesticides are sometimes used for the preservation of natural fibers and these are transferred to wastewater during washing and scouring operations. Some discharged chemicals are toxic and cause damage to aquatic life (Kovals, 1999).

Table 2.4 shows wastewater characteristics of each processing, and Table 2.5

shows typical compilation of discharge standards in several countries for the textile industry. Table 2.4 Wastewater Characteristic of each Processing

Process Waste volume m3/ton of cotton

BOD5Kg/ton of cotton

TSS Kg/ton of cotton

Average compounded 1 265 115 70 Yarn sizing 4.2 2.8 - Desizing 22 58 30 Scouring 100 53 22 Bleaching 100 8 5 Mercerizing 35 8 2.5 Dyeing 50 60 25 Printing 14 54 12 Source: Economopoulos (1993) 1 The average compounded load factors listed are based on the assumption that only 35% of the mercerized, 50% of the product is dyed and 14% of the product is printed. Table 2.5 Typical Compilation of Discharge Standards in several countries for the Textile Industry. Parameter Germany Indonesia Japan Venezuela India Thailand pH - 6-9 5.8-8.6 6-9 5.5-9 5.5-9 Temp. (0C) - - - - - 40 BOD5 (mg/L) 40 85 160 60 100/150 20/60 COD (mg/L) 280 250 30/120(1) 350 - 120/400 SS (mg/L) 40 60 200 60 100 50 Oils (mg/L) - 5 5/35 20 10 5 Color - - - 500(2) - - Phenol (mg/L)

- 1 5 5 5 1

Cr (mg/L) 2 2 (total) (3) 0.5 (VI) 2 (total) (3)

0.5 (VI) 2 (total) (3)

0.1 (VI) 2 (total) (3)

0.25 (VI) 0.75 (III)

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Source: UNEP (1994) and MOSTE (1996) (1) COD (Mn) (2) Pt/Co unit (3) Total Chromium 2.5 Wastewater Treatment

Dyeing wastewater is difficult to treat because the textile processing methods and

conditions, as well as dyestuff, dyeing auxiliaries used, vary depending on whether the textile is cotton, linen, wool, chemical based or synthetic. Operation at dye works involves processes, such as bleaching, dyeing, printing and finishing. Wastewater treatment methods vary depending on whether all or parts of these processes are used.

Primary Treatment: Screening, equalization and neutralization are primary treatment methods. Screening is removing coarse flotation matter. Equalization is retaining waste in a basin so that the effluent discharged is fairy uniform in its characteristic to prevent shock loads and also neutralize pH to meet requirements of the secondary treatment.

Biological Treatment: The most widely used biological methods for treating dyeing

wastewater are trickling filters, activated sludge and aerated lagoons. Biological treatment is capable of providing high BOD, COD and SS removal but it is less effective for color removal as most synthetic dyes are extremely resistant to biological degradation. Trickling filters is generally desirable from the standpoint of flexibility; lower operating costs, and capability of handling shock loads of waste. Activated sludge gives greater BOD reduction, but entails large units to provide the long detention times usually needed and also requires highly qualified supervision. Aerated lagoon generally gives somewhat lower BOD reduction than activated sludge, but does away with the sludge problem; it also takes a minimum of operation and maintenance (Nemerow, 1978).

Chemical Treatment: Chemical coagulation, activated carbon adsorption, ion exchange and synthetic polymeric adsorbents can be used for the treatment of dyeing wastewater. Chemical coagulation is an effective means of reducing the color of wastewater and of reducing BOD, COD and other components. The main types of coagulant used for color removal are alum, ferrous sulfate and ferric chloride. Activated carbon adsorption is an effective unit process for removing colored wastewater. Granular activated carbon (GAC) in form of a bed like a sand filter is used. Ion exchange is suited for dilute solutions. In the treatment of discharge from dye house, anion resins have demonstrated a strong affinity for anionic dyes while cation resins have readily removed cationic dyes. Synthetic polymeric adsorbent function is like activated carbon. They remove organic compounds from wastewater by adsorption involving van der vaals forces (Hussain, 1994).

Ozonation: Ozone can be employed to remove BOD, COD and color. Ciardlli and Ranieri, (1999) found the ozonization can be used to remove color (95-99%) and COD (decrease up to 60%) to an extent that is sufficient for water reuse even in critical conditions as dyeing with light tones. Operating conditions necessary to achieve this level of purification are compatible with low operating costs.

Membrane Processes: Membrane separation of solids from wastewater is actually a

subset of filtration. It can be used to separate color from dye effluents that much smaller

9

than those removed by other filtration process. They can be used to treat either the combined effluents or point source. Membrane processes are very effective, but the rate of transfer across the membranes is generally slow and pressures are high; large membrane areas are required. Membrane filtration includes ultra-filtration, dialysis, electrodialysis, reverse osmosis and so on. Reverse osmosis has been found to be applicable to industrial wastewater (Bishop, 2000). Figure 2.2 shows the various wastewater treatment options for dyeing industry. 2.6 Waste Audit

A waste audit is the first step in on-going program designed to achieve maximum resource optimization and improved process performance. It is a common sense approach identification and problem solving.

A waste audit enable you to take a comprehensive look at the site or process to facilitate your understanding of material flows and to focus your attention on areas where waste reduction and therefore cost saving is possible (UNEP/IEO and UNIDO, 1991). The step in planning and implementing a waste auditing program is shown in Figure 2.3

2.7 Waste Minimization Visvanathan et al. (1994) described the waste minimization consists of source reduction and recycling. Source reduction is usually preferable to recycling from an environmental perspective. Source reduction is any activity that aims to eliminate the generation of waste at its point of origin, while recycling is the reusing, recycling, or reclaiming of materials and waste, including processes that regenerate a material or recover a usable product from it. Waste minimization involves the use of raw material, processes or operating practices in a manner that prevents the creation of pollutants or wastes at their source, and those practices that reduce the use of hazardous and non-hazardous materials, energy, water or other resources. Waste minimization can be illustrated in Figure 2.4.

10

Equalization

pH-Adjustment

Screening

Biological Treatment

Membrane Processes

Chemical Treatment

Ozonation

Aerated Lagoons

Activated Sludge

Trickling Filter

Synthetic Polymeric Adsorbent

Electrodialysis

Ultra-filtration

Chemical Coagulation

Reverse Osmosis

Activated Carbon

Ion-exchange

Ferrous Sulfate

Lime Alum Ferric Chloride

Source: Hussain (1994)

Figure 2.2 Various Dyeing Wastewater Treatments

11

PHASE 1: PREASSESSMENT

DRIVE A MATERIAL BALANCE Step 11 assemble input and output information Step 12 derive a preliminary material balance Step 13 and 14 evaluate and refine material balance

PHASE 2: MATERIAL BALANCE

PROCESS INPUTS Step 4 determine inputs Step 5 record water usage Step 6 measure current levels of waste reuse/recycling

PROCESS OUTPUTS Step 7 quantify products/by-products Step 8 account for wastewater Step 9 account for gaseous emission Step 10 account for off-site wastes

PHASE 3: SYNTHESIS

WASTE REDUCTION ACTION PLAN Step 20 design and implement a waste reduction action plan to achieve improved process efficiency

EVALUATE WASTE REDUCTION OPTIONS Step 19 undertake environmental and economic evaluation of waste reduction options list viable option

IDENTIFY WASTE REDUCTION OPTIONS Step 15 identify obvious waste reduction measures Step 16 target and characterize problem wastes Step 17 investigate the possibility of waste segregation Step 18 identify long term waste reduction measures

Source: UNEP/IEO and UNIDO (1991)

Figure 2.3 A Waste Audit Plan

12

Waste Minimization Techniques

Product Changes - Product substitution - Product conservation - Change in product composition

Recycling Source Reduction

Source Control

Reclaimation - Processed for resource recovery - Processed as a by-product

Use and Reuse - Return to original process - Raw material substitute for another process

Material Changes

- Material purification - Material substitution

Technology Changes - Process changes - Equipment, piping, or layout changes - Additional automation - Changes in operational settings

Good Operating Practices - Procedural measures - Loss prevention - Management practices - Waste stream segregation - Material handling improvements - Production scheduling

Source: Janesiripanich (1995) Figure 2.4 Waste Minimization Techniques

13

2.8 Wastewater Minimization

Wang and Smith (1994) presented four general approaches to wastewater minimization as follows:

1) Process change: Process changes can reduce the inherent demand for water. An

example is the replacement of wet cooling towers by dry air coolers. 2) Water reuse: Wastewater can be reused directly in other water using operations when the level of previous contamination does not interfere with the water using operation. This reduces both freshwater and wastewater volumes but leave the mass load of contaminant essentially uncharged. See Figure 2.5a. 3) Regeneration reuse: Wastewater can be regenerated by partial or total treatment to remove the contaminants that would otherwise prevent reuse and then can be reused in other water using operations. The regeneration is any operation that removes the contaminants that prevent reuse and could be filtration, pH adjustment, carbon adsorption, and other processes. Regeneration reduces both freshwater and wastewater volumes and decreases the mass load of contaminant. See Figure 2.5b. 4) Regeneration recycle: Wastewater can be regenerated to remove contaminants and then the water recycled. In this case, regenerated water may enter the water using operations in which the water stream has already been used. Also, recycle can sometimes create a buildup of undesired contaminants not removed in the regeneration process. See Figure 2.5c. Freshwater Wastewater Reuse

Operation 1

Operation 2

Operation 3 (a) Freshwater Wastewater Reuse

Operation 3

Operation 1

Operation 2 Regeneration

14

(b) Recycle Freshwater Wastewater

Operation 2

Operation 3

Operation 1

Regeneration

(c) Figure 2.5 Water Minimization through (a) Reuse, (b) Regeneration reuse, and (c) Regeneration recycle (Smith, 1994)

Visvanathan (2001) identified the industrial wastewater reuse into three ways as

follows: 1) Internal wastewaters recycle: Depending on the manufacturing process, water

consumption can be cut down between 50% to 90% by adopting appropriate water recycling techniques. In Japan, 6.7% water recirculated in the textile industries.

2) Reuse of treated industrial wastewater. 3) Reuse of treated wastewater for other activities such as irrigation, fire

protection, dual system etc.

NC DEHNR (1993) recommended for in-plant reuse without treatment is given for each of the major operations as follows;

1) Good housekeeping: Good housekeeping in textile industries is a program of maintenance, inspection, and evaluation of production practices should be established. Implementing the following can make significant reductions in water use:

- Minimizing leaks and spills - Maintaining production equipment properly - Identifying unnecessary washing of both fabric and equipment, and - Training employees on the importance of water conservation.

2) Reuse of water in scouring and bleaching: It is the clearer wastewater from the

later washes in a bleaching sequence can be reused in some of the earlier washed where water quality is not so important.

3) Reuse in mercerizing: On the mercerizing range, the scope for water conservation and reuse lies in adopting a countercurrent flow pattern. The water

15

requirement can be reduced, if most of this water can be recovered as steam condensate from the multiple effect evaporators of the caustic recovery plant provided suction in the evaporations is carefully controlled to avoid boiling over.

4) Reuse in dyeing: Small saving can be effected if running washes are replaced by static ones wherever possible. Further, the batching or wetting water need not be drained out. It can be retained for use in the next operation like dyeing or naptholating.

5) Reuse in printing and finishing: This section uses water for various cooling and washing operation and reuse steam condensates in boilers.

6) Reuse of soaper wastewater: The colored wastewater from the soaping operation can be reused at the backgrey washer, which does not require water of a very high quality. Alternatively, the wastewater can be used for cleaning floors and equipment in the print and color shop. 7) Reused of mercerizing or bleach wash water for scouring or desizing: Mercerizing or bleaching rinse water can be used in scouring and desizing operations, as size recovery is not practiced. Generally, the caustic or bleach stream will degrade many size compounds to an extent that cannot be recovered.

8) Counter current washing: Counter current washing is an employed frequently on continuous preparation and dye range. Clean water enters at the final wash box and flow counter to the movement of the fabric through the wash boxes. Thus, when the fabric enters these the actual wash process, the most contaminated wash water contacts it first, and, later, the cleanest water contacts the cleanest fabric. It can be applied at desize washers, scour washers, mercerizing washers, bleach washers, dye ranges, and print house soaper range.

9) Use of automatic shut-off valves: An automatic shut-off valve set to time, level, or temperature will control the flow of water into a process unit. One plant estimated that a reduction in water use of up to 20% could be achieved with thermally controlled shut-off valves.

10) Use of flow control valves: A flow or pressure reduction valve can significantly reduce the quantity of water used in a wash or clean-up step. These valves are particularly useful in cleaning areas where operators are not always aware of the need for water conservation.

Visvanathan et al., (1994) explained about dual pipe systems that are installed for the steam condensate and cooling water collection and reuse. The condensate is recycled back to the boilers. The cooling water is collected in a storage tank, and is used as non-process washing water (washing handling tools, floor washing etc.). Reutilization of steam condensate and cooling water accounts for saving raw water and at the same time reduces the volume of wastewater being discharged.

UNEP (1994) recommended the reusing of wastewater could be done by: 1) Recycle/reuse of water jet weaving wastewater: The jet weaving wastewater can

be reused within the jet looms. Alternatively, it can be reused in the desizing or scouring process, provided that in-line filters remove fabric impurities and oils.

16

2) Reuse of pressure filter backwash water: Easily settable suspended solid is the

main pollutant in the pressure filter backwash. By collecting this in a pond with a minimum hydraulic retention time of 12 hours the supernatant free from suspended solids can be reused for gardening purposes. Periodically the retained suspended solids will be removed from the pond and disposed of as solid waste in a landfill site.

3) Reuse of wastewater from the dyeing and finishing department: Fresh water is used for quenching hot ash from the boiler house before disposal. It is feasible to reuse the hard to treat wastewater from the dyeing department, instead of fresh water, for quenching purposes. It was also confirmed that due to adsorption of color/dyes on the ash particles, there would be about 20% reduction in BOD content in the reused dye-house wastewater.

4) Reuse of wastewater from sizing activities: To avoid spontaneous combustion and to reduce the fine loss, fresh water is used for wetting coal in the yard. By collecting the low volume high organic strength wastewater from the sizing operation in a pond with facilities to prevent septicity, the entire wastewater arising can be used for coal wetting.

UNEP (1994) recommended using pre- washing in any single stage system and

much other abbreviated bleach configurations. Pre-washing can remove significant quantities of sizing and natural impurities, which would otherwise have to remove in the final washes, and which might affect the stability of the bleach bath. Since pre-washing with recycled water does not affect water consumption.

Visvanathan et al., (1994) reported, the innovation of dyeing process that the new computerized dyeing techniques will produce better quality and higher efficiency of the dyeing process. It will also guarantee more economical use of the chemicals and dyestuff, as well as reduction in wastewater generation as a result of avoiding the re-dyeing operations. Including reduce the amount of raw material consumption. 2.9 Segregation of Wastewater

Visvanathan (2001) described the segregation of wastewater assists to reduce the strength and the difficulty of treating final waste. It has two mains:

1) Collection of strong and lower volume waste is easier and more economical to

treat than the large volume and diluted wastes. 2) Collection of diluted large quantity wastewater can be treated with the simple

treatment techniques and be reused in the process system.

Visvanathan et al., (1994) described the wastewater segregation has been recognized to be an important part of the waste reduction strategy. This offers long term cost-saving in terms of reducing the treatment cost. 2.10 Water Pinch Analysis

17

Water pinch analysis is a tool to guide water and effluent management decisions. It can improve the efficiency and guide process modifications. Moreover, it can minimize raw water demand and also reduce the wastewater generation. Wang and Smith (1994) presented a pinch analysis for wastewater minimization, by carrying out the minimum concentration differences through out the network. The contaminate mass load in the water stream was focused, rather than the process streams. By formulating for the system between the rich and lean streams. This methodology is applicable to all water using operation, that different solvents and concentrations. Pinch point is the point where the mass transfer driving forces were indeed reduced to the minimum. It could be located where the water supply line touched the limiting composite curve.

18

Chapter 3

Background Information of the Research Site

3.1 General Background

The research site is a medium sized dyeing factory, located in 1,860 m2 areas at Samut Prakarn Province. The factory has been operating since 1993 and produces about 789 tons bath towel per year. Raw materials are cotton yarns produced in Thailand and imported from Pakistan about 835 tons per year. The factory has 150 employees, and the factory operates six days per week. The plant location is shown in Figure 3.1 and the plant layout is shown in Figure 3.2 3.2 Production Processes

There are six sections in this factory that can classify as below: 1) Spinning and warping section are located on second floor of the building. There

are four spinning machines and two warping machines. The warping machines are supplied the air by two pumps. This section is operated eight hours per day.

2) Sizing section, there is one sizing machine that operates sixteen hours per day.

Small volume of wastewater from this section is directly discharged to drainage channel beside the plant.

3) Weaving section there is twenty-nine weaving machines that operate twenty-four hours per day. This section has an automatic controller controls temperature and humidity. Small amount of water is used.

4) Dyeing section includes desizing, scouring, bleaching, dyeing and finishing

processes. Dyeing section use three winch machines and one fong machine. The dyeing operates with liquor ratios ranging from 1:8 to 1:10. Three winch machines are operated with a load of 180 to 240 kg of fabric per batch and work three batches per day. Fong machine works two batches per day and operates with a load of 300 to 420 kg of fabric per batch. Dyeing process is reactive dyes that it is used for cotton cloth. This section operates sixteen hours per day.

5) Drying section is located on second floor and is separated into two steps; first the

dye cloth is dried in big one of dryer machine. After that is dried in small dryer, these are six machines. This section operates eight hours per day.

6) Sewing, inspecting and packaging section, there are fourteen sewing machines.

This section operates eight hours per day.

In first step, cotton yarns are spinning and warping. Then yarns are carried to sizing and weaving process. These processes get unbleached muslin that must be sent to inspection and kept in storage room or carried to dyeing process. In the batch, operation includes desizing, scouring, bleaching, dyeing and finishing. Cloths are dried in a dryer,

19

after that is brought to cutting and sewing section. Finally, the quality control section inspects the products before are packaged and distributed to customer. The various steps involved in the process are shown in Figure 3.3 and 3.4. 3.3 Organizations and Production Activity Schedule Figure B-1 and Table B-5 in Appendix B shows the organization chart of this factory and the production activity schedule of workers in each section. Normally, working time is start from 07.30 am to 17.30 pm, except dyeing and weaving section are operated sixteen and twenty-four hours per day, respectively. 3.4 Environmental Problems Issues of the Factory

The most significant environmental problems from production processes in the factory are following: • Raw water: High water consumption in production process. In the future cost of ground

water will be increased, and water supply is not enough for using. • Wastewater: Large amounts of wastewater contain high SS, TDS, BOD, pH and color. • Noise: Weaving machines make noise pollution • Dust: Cotton dust is dispersed in all of plant areas. • Heat waste: Steam leakage and hot wastewater.

20

Fig 3.1

21

Sump

2 4

3

1

WellIncinerator

New Building

Packaging Section

Products Storage

Sizing Section

WWTP

Office

Weaving Section

Dyeing Section

Dormitory Car park

Entrance

Public canal

Wat Kusang Road

Guard house

Remark:

1 - Boiler 2 - Fuel oil Storage tank 3 - Treated water tank 4 - Softener unit

Figure 3.2 Plant Layout of the Factory

22

Noise Spinning Cotton Dust Warping Dust

Sizing Steam Dust Noise

Weaving Dust

Desizing

Scouring and Washing

Dyeing and Washing

Fixing and Washing

Softening and Washing

Bleaching and Washing

Fresh water Steam

Noise

Wastewater

Heat waste

Heat waste

Wastewater

Chemicals

Centrifuging

Drying Steam

Cutting & Sewing WWTP

Inspecting & Packaging

Products Figure 3.3 Flow Chart of General Production Processes

23

Fig 3.4

24

Grey Fabric WW Desizing

90 0C

Scouring and Bleaching

100 0C

Dyeing

60 0C

Centrifuging

Fixing

Softening

Washing I

WW

WW

WW

WW

WW

WW

Washing II

Washing III

Washing IV 100 0C

Washing V

WW

WW

WW

Washing VI

WWTP

Water, Steam

Soaping agent

Enzyme

Water, Steam

NaCl

Soaping agent Surfactants

NaOH Hydrogen peroxide Brightening agent Water

Water

Reyonets

Water, Steam NaOH Surfactants

Na2SO4

Dyestuff Dispersing agent

Soda ash

Water Steam

Water Soaping agent

Formic acid Water Water

Water

Fixing agent

Water WW

Softener agent

Figure 3.5 Cotton Fabric Dyeing Process

25

3.5 Water Consumption and Treatment

Water is obtained from two sources, ground water for production process around 110,814 m3/year, and another once is water supply for boiler and officer using around 6,402 m3/year. Ground water is treated by activated carbon and ion exchange resin tank before using. The treated water is stored in the water tower. Most is used for dyeing processes. Figure 3.6 shows a flow diagram of the water treatment and distribution.

Dyeing Section

Ion exchange Resin

Treated Water Storage Tank

Treated Water Tower

Ground Water Storage

Salt Water

Activated Carbon

Sizing Section

Floor and tools Cleaning

Treated Water

Well Ground Water

Figure 3.6 Raw Water Treatment and Distribution 3.6 Energy Consumption The two major energy inputs to the factory are in form of steam and electricity. The boiler that operates fuel oil, 600,000 liters per year, produces steam. Total electricity used of the factory in 2001 is 1,433,000 kWh per year. 3.7 Solid Waste Management Solid waste generated from this factory can be identified in Table 3.1, which is collected by 100 liters container. The factory has an incinerator for disposing in plant.

26

Table 3.1 Solid Waste Management in the Factory.

Type Sources Disposal Methods Cotton dust Spinning, warping, sizing,

weaving Incinerator

Yarn waste/rejected fabric

Weaving, cutting Incinerator

Sludge

WWTP Fill up space area near the plant

Other waste such as plastic bag, paper

Worker and packaging Incinerator

3.8 Chemicals Consumption

Chemical substances are mainly used in dyeing processes. Dyestuffs are used about 4.2 tons/year, are kept in storage room and handled by the workers in the color storage room. About 366 tons/year of other chemicals are used in the dyeing processes and these are stored and handled in the dyeing area. All of chemical substances used in production process are shown in Table A-4 in Appendix A. 3.9 Wastewater Treatment Plant

There are three wastewater streams as follows: 1) storm water 2) domestic wastewater and 3) industrial wastewater. The storm water is directly discharged into public canal. Domestic wastewater is collected by septic tank. Industrial wastewater from production processes are collected by gutter and flowed to sump tank. This wastewater is pumped through the cooling tower and flowed to rapid and slow mixing tank for coagulation and flocculation. Then wastewater sent to first sedimentation tank and aeration tank, respectively. The aeration tank has two aerators; each aerator is operated ten hours per day for oxygen supply. After that wastewater is transferred to the second sedimentation tank and transfer to the effluent tank. The sedimentation tank and the effluent tank are presently out of use and the aeration tank is used as a settling tank instead. The effluents are pumped two times a day to the drainage channel and discharged into public canal. The sludge is pumped for filling up space area near the plant. Flow diagram of wastewater treatment plant is shown in Figure 3.7. 3.10 Wastewater Characteristics

The characteristic of wastewater are recorded and analyzed by Sahapornprom Co, Ltd. The influent and effluent samples are taken one and four times per month by grab sampling method, respectively. The results of characteristic analysis are shown in Table 3.2.

27

Table 3.2 Range of Wastewater Characteristic of WWTP (January-June, 2001)

Parameter January February March April May June pH -Influent -Effluent

9.72

7.96-8.34

10.55

7.88-9.08

8.45

7.62-8.68

9.32

8.08-8.65

9.68

8.43-8.88

-

7.97-8.43

BOD5 (mg/L) -Influent -Effluent

660

14-48

750

4.8-24

310

23-153

190

7.8-44

170

19-47

-

32-63

TDS (mg/L) -Influent -Effluent

4,560

4,040-4520

4,950

4,180-5,120

10,740

3,970-4,650

3,210

4,460-4,720

3,210

3,790-5,010

-

4,820-5,410

SS (mg/L) -Influent -Effluent

146

41-93

124

36-79

102

63-257

127

83-180

89

50-85

-

57-112

Source: Analysis Report of Sahapornprom Co, Ltd.

28

Fig 3.7

29

Chapter 4

Methodology

4.1 General Study Program

The general study program involves: (1) Waste audit of the process to find out the pollution problems by plant walkthrough,

observing, measuring, recording and collecting data. (2) Analysis of wastewater samples during process and evaluates the possibilities of

wastewater segregation during process for reducing wastewater. (3) Analysis of wastewater samples from wastewater treatment plant for improving

treatment efficiency.

The final of this study is conclusion and recommendation to the factory to achieve wastewater minimization options. The methodology is shown schematically in Figure 4.1. 4.2 Waste Audit Studies

First step of waste audit is to get co-operation from the manager of the factory. Then plant walkthrough for observing and understanding the production processes, raw materials consumption, products, energy consumption, chemicals consumption, water consumption, wastewater quantity and source, flow measurements, sampling, analysis wastewater characteristic and preparation of mass balances. Eco-mapping was done in this study, to get an overview of the status of the environment problems in plant. 4.2.1 Water Supply System

Water supply and distribution systems were studied to find out the water

consumption problems, and to investigate the leakage along the water pipeline. 4.2.2 Water Consumption Measurement

Sources of groundwater and water supply are observed. Daily water consumption was measured by existing flow meter. 4.2.3 Sampling Methods

Wastewater generated from the unit process was collected to determine the characteristics. Both grab and composite sampling methods are used for collecting wastewater.

(a) Composite sampling in dyeing processes, wastewater samples were collected

from the discharge points of the dyeing machines. Sampling points are shown in Figure 4.2 (b) Grab sampling in unit of wastewater treatment plant that has three points are

sump tank (influent), after passed the slow mixing tank and aeration tank (effluent). Sampling points are shown in Figure 4.3

30

Plant Walkthrough

Study the production process

Eco- mapping

Water and Wastewater Audit

Energy Audit

Treatment Plant

Analysis

Proposal for Wastewater Segregation

Wastewater Reuse WWTP Improvement Energy Conservation

Results & Discussion

Conclusion & Recommendations

Figure 4.1 General Methodology Outline

31

Desizing

Scouring and bleaching

Dyeing

Centrifuging

Fixing

Softening

WWTP

Washing I

WW

WW

WW

WW

WW

WW

WW

Grey Fabric

Washing II

Washing III

Washing IV

Washing V

WW

WW

WW

7 8 9 10 11

6

5

3 4

1

2

Washing VI

Water, Steam Soaping agent

Enzyme

Water, Steam NaCl

Soaping agent Surfactants NaOH Hydrogen peroxide

Brightening agent

Water

Water Reyonets

Water, Steam

NaOH Surfactants

Na2SO4 Dyestuff Dispersing agent Soda ash Water

Steam Water Soaping agent

Formic acid Water

Water

Water Fixing agent

Water WW

Softener agent Figure 4.2 Sampling Points of Dyeing Processes

32

Fig 4.3 Sampling point in WWTP

33

4.2.4 Water and Wastewater Characteristic Water: Total hardness, TDS, pH, Turbidity

Wastewater: pH, Temperature, BOD, COD, SS, TDS, color, Total Cr and Cr+6

All analysis followed the Standard methods (APHA-AWWA-WPCF, 1989) and was

conducted at the Environmental Engineering Laboratory in AIT. The analytical parameters and the corresponding methods used for determination of wastewater characteristics are shown in Table 4.1

Table 4.1 Analytical Parameters, Locations and Methods

Location Parameter Method & Equipment On-site pH

Temperature pH meter Thermometer

Laboratory Turbidity BOD5COD TDS SS Total hardness Color Total Cr, Cr6+

Nephelometric meter Azid Modification at 20 0C for 5 days Potassium dichromate digestion Evaporated at 103-105 0C Gravimetric Titration Spectrophotometer Atomic absorption spectrophotometer

4.2.5 Wastewater Flow Measurement

Flow rates of wastewater from production process of the factory were measured by bucket and stopwatch method. Figure 4.4 shows the bucket and stopwatch for measuring wastewater flow rate.

Figure 4.4 Bucket and Stopwatch Measurement

34

4.2.6 Mass and Water Balance

Evaluation of the mass and water balances, and compare with the benchmark. The raw material, production, steam, chemicals, water and wastewater generations during process were measured. 4.2.7 Energy Audit The historical data were analyzed and walk-through audit was conducted to get an idea about the factory energy performance. This study serves two purposes at the same time: energy conservation and safety of working condition in the factory. The following measurements could be made:

(a) Electricity and fuel oil consumption The historical data of electricity and fuel oil consumption were collected and analyzed.

(b) Steam and condensate pipe systems

Walk-through audit was conducted to get the steam leakage and heat loss problem from the plant.

(c) Heat loss study The estimated reduction of heat loss can be calculated and was compared between insulated and uninsulated pipes or tanks. 4.3 Air and Noise Pollution in the Workplace

4.3.1 Airborne Particulate Matter Measurement

Personal pumps and 37 mm, 0.5 um PVC filters were used for airborne particulate measurement. The area of this factory, which was, selected as weaving section, sizing section, drying section, spinning and warping section. Figure 4.5 and 4.7 shows the air sampling instrument and sampling points in this study, respectively.

4.3.2 Noise Measurement

Integrated Sound Pressure Level Meter was used to measure the noise values in term of dB (A). Figure 4.6 shows equipment that was used in this study. Figure 4.8 shows sampling points of noise measurement. Sources of noise in the factory such as weaving machines, dyeing machines, spinning and warping machines.

35

Figure 4.5 Airborne Particulate Sampling Equipment

Figure 4.6 The Integrated Sound Pressure Level Meter

36

Figure 4.7 Airborne particulate sampling points in plant area

37

Figure 4.8 Sampling Points for Noise Measurement

38

4.4 Wastewater Segregation Study

The current status of wastewater stream segregation was evaluated. Then the possibility for better wastewater stream segregation on during dyeing process is proposed. This step of the study was carried out by analysis of effluent streams from the dyeing process in terms of COD, and color values. 4.5 Wastewater Treatment Plant Study

In this study, wastewater treatment plant was surveyed and wastewater characteristic was analyzed to evaluate its current operational problems and efficiency. Coagulation was studied by Jar test to determine the optimum condition and coagulants for maximum COD and color removal of wastewater. The settleable solids were determined using an Imhoff cone for comparing the quantity of sludge from combined wastewater and after segregation. 4.6 Water Pinch Analysis

Water pinch software developed by Mr.Parinya Boonkasem was used for analysis to guide water and effluent management. This tool can be computed by using the computer.

4.7 Wastewater Minimization Options

This study identified wastewater minimization potentials that appropriate to this

factory.

4.8 Economical Feasibility Analysis

The objective is to demonstrate the feasibility of investment and benefit cost of pollution prevention in the factory. This study will calculate cost that the factory will pay and compare between before modification and after modification. Payback period is indicated to decision making.

39

Chapter 5

Results and Discussion 5.1 Plant Walkthrough Audit Eco-mapping is used for plant walkthrough audit. It is a simple and practical tool to analyze and manage the environmental performance of factories and industries. In this study, this tool is used for conducting an environmental review as well as for leaning and collecting data in order to define and priority problems within the factory.

5.1.1 Questionnaires Twelve factory members were interviewed regarding the environmental management problem in the factory. One is personal manager, five members are leaders of each section and six workers are chosen as random from all sections. Table 5.1 summarizes the results. As a result from the interview, major environmental issues within this factory can be prioritized as below:

1) Wastewater treatment 2) Noise reduction and control 3) Cotton dust control 4) Use and save of electricity

5.1.2 Eco-Mapping

Figure 5.1 to 5.5 shows the surrounding environment, eco-map of water and wastewater, eco-map of energy, eco-map of solid waste, eco-map of noise and dust. The symbols are used for identifying location, problems and the area that the factory should be carefully observed and considered. Figure 5.1 shows the surrounding environment of factory where there are six factories and two communities’ areas in one-kilometer radius. Wastewater from this factory were treated and discharged into a public canal in front of the factory, which is normally used as drainage system. Figure 5.2 shows the eco-map of water and wastewater, indicating the raw water system, wastewater channels, location of bad practice in term of water using and main area of wastewater generation. The major problem area is dyeing section, which consumes high volume of water and generates large quantity of wastewater. During plant walkthrough audit, many problems are found such as:

- Use of treated water for floor cleaning. - Wastewaters are not separated based on high and low pollution concentration. - No internal reuse of water within a process. - Treated wastewater is not recycled for other activities.

40

Figure 5.3 shows the eco-map of energy, indicating the location of machines, steam line, location of steam consumption and area of leakage. During the walk through audit, the following problems are observed:

- No record of steam flow in the production processes. - At drying section, steam piping around ten meters length is not insulated. - No plan for maintenance the steam traps, causing to return of steam. - Condensate pipe of storage tank is damaged. - Feed water tank, piping and storage tank of condensate are not insulated. - The first dryer is not properly insulated.

Figure 5.4 shows the eco-map of noise and dust, indicating the location of noise and dust problems. Weaving section is the main area of noise pollution and cotton dust. Spinning section, sizing section and warping section are sources of dust problem. In this case, dust is difficult to control because of its dispersion in all areas. The factory does not have equipment for preventing noise pollution. Figure 5.5 shows the eco-map of solid waste, indicating the location of bins or containers, and location of bad practice in the factory. Problems found in this factory are as follows:

- Old machines and equipments that out of use are kept in not suitable areas. - Bins or containers are not separated for each type of solid waste. - Yarn wastes and cotton yarns are collected in the same area. - Lubricant oil containers are not kept in safe area.

Table 5.1 Summary of Environmental Management Questionnaires

Items Total point Priority Use of raw materials/Cotton yarns 25 9 Use and save of electricity 37 4 Use and save of fuel oil 25 9 Lighting in workplace 23 10 Use of water and leakage 29 8 Wastewater treatment 41 1 Prevention and reduction of solid waste 32 7 Recycle and reuse of waste 33 6 Cotton dust control 38 3 Storage of products/raw materials 31 7 Reduction and control of noise 40 2 Health and safety in the workplace 29 8 Prevention of environmental accidents 29 8 Environmental information (internal) 23 10 Surrounding environment problems 36 5

41

Fig 5.1

42

Fig 5.2

43

Fig 5.3

44

Fig 5.4

45

Fig 5.5

46

5.2 Material Consumption and Wastewater Generation

5.2.1 Raw Material Consumption Table A-1 in Appendix A presents the raw materials that are used in the dyeing

process. Cotton yarns are consumed around 69.65 tons/month or 2,790 kg/day, which can produce bath towels around 65.79 tons/month or 2,630 kg/day. The product yield in 2001 was 94.5 % of raw material.

5.2.2 Water Consumption Deep wells are the main sources of groundwater for the factory that is treated before usage by a softener process through ion exchange resin and activated carbon. Figure 5.6 shows the distribution of water usage in the plant. In 2001 (January - December), groundwater is supplied for this factory around 8,793 m3/month or 352 m3/ day. Moreover, water supply is used for dormitory, toilet, boiler and office around 534 m3/month or 18 m3/day. Water consumption was estimated based on reading of the exiting meter, which was installed in the pumping station. Sizing process

Groundwater Treated water Dyeing process Resin tank cleaning

Floor, hand and Tools cleaning

Dormitory

Water supply Office, Toilet

Boiler

Figure 5.6 Distribution of Water Use in the Factory

Amount of treated water is required daily for sizing process 6 m3/day, dyeing

processes 327 m3/day, floor, hand and tools cleaning 16 m3/day, resin tank cleaning 2 m3/day, respectively. Therefore, the total treated water consumption is 351 m3/day.

Water supply used by twenty persons who live in dormitory, for washing, bathing,

cooking, and other activities is estimated to be 5 m3/day. This estimation is based on the number of the resident and the standard water use values for domestic use (daily consumption is 250 L/person/day).

Water supply used by officer and worker (140 persons) in the plant for toilet, hand washing, etc. is estimated as 7 m3/day. This is based on the number of worker and the standard water use values for factories that the daily consumption is 50 L/person/day (Metcalf, 1991).

47

The boiler supplies steam and heated water to the dyeing, sizing and drying section. This factory has never measured feed water use for boiler. However, almost of the condensate is recycled back to feed water tank before is pumped to boiler. Therefore, the consumption of water for boiler should be small volume. It can be estimated from remaining of total water supply as 6 m3/day.

The annual record of water and production are shown in Table A-1 in Appendix A that the average daily water consumption for this factory is 141 m3/ton of products. When compared to the standard norm, it is still within the maximum value of water usage per ton of product. Table 5.2 Daily average amount of water used that was compared with Standard of Thailand (1999), and US EPA (1979) data.

Standard of Thailand* (m3 /ton of product)

Standard of US EPA* (m3 /ton of product)

Type of factory Research site (m3 /ton of product) Min Max Min Max

Dyeing and finishing (Fabric)

141

125

160

5

507.9

Source: *Kumar et al (1999)

Figure 5.7 presents overall water consumption for each of activity in terms of total quantity and percentage. Water is used for dyeing processes, floor and tools cleaning in dyeing section is 343 m3/day (92%), which is the highest volume of all. Figure 5.8 (a) shows the monthly trend of groundwater consumption in the factory.

Total water consumption 369 m3/d

Boiler2% Other

2% Resin washing1%

Floor and tools cleaning

4%Domestic1%

Sizing2%

Dyeing88%

Figure 5.7 Overall Water Consumption

48

0

500

1000

1500

2000

2500

1 2 3 4 5 6 7 8 9 10 11 12

Month

Elec

trici

ty C

onsu

mpt

ion

(kW

h/to

n)

(a)

0

50

100

150

200

1 2 3 4 5 6 7 8 9 10 11 12

Month

Gro

undw

ater

Con

sum

ptio

n (m

3 /ton)

(b)

0

200

400

600

800

1000

1 2 3 4 5 6 7 8 9 10 11 12

M onth

Fuel

Oil

Con

sum

ptio

n (L

/ton)

(c)

Figure 5.8 Trend of Monthly Consumption (a) Groundwater (b) Fuel Oil (c) Electricity (Unit per ton of products)

49

5.2.3 Energy Consumption Table A-1 in Appendix A and Figure 5.8 (b) and (c) show the energy consumption data, estimated by using the available data from the factory. Electricity and steam are two major energy inputs for the production processes in the factory. The average electricity used of the factory is 119,417 kWh/month or 1.82 MWh/ton of products. The boiler produces steam, which is capacity of 3.0 tons/h. It operates around 18 hours per day and consumes fuel oil around 50,000 L/month or 760 L/ton of products. Therefore, fuel consumed by this boiler is 27,778 MJ or 27.8 GJ per ton of products, based on the heating value of fuel oil is 42.5 MJ/kg and specific gravity of fuel oil is 0.86 kg/L (Miyamoto, 1996). The comparison of energy consumption to standard norm is presented in Table 5.3. The result shows electricity consumption is higher than standard of Thailand, and fuel consumption per ton of product is within the range of standard. However, when compare to UNIDO standard both electricity and fuel consumption is lower. Table 5.3 Comparison of energy consumption with standard of Thailand (1999),

and UNIDO.

Type of factory

Research site Standard of Thailand*

Standard of UNIDO*

Electricity (MWh/ton)a

Fuel (GJ/ton) a

Electricity (MWh/ton) a

Fuel (GJ/ton) a

Electricity (MWh/ton) a

Fuel (GJ/ton) a

Integrated textile mills

1.82

27.8

0.2-1.2

25.8-50

13.9 – 26.4

68-70

Source: *Kumar et al (1999) aTon of product

5.2.4 Chemical Consumption The uses of all chemicals are different for different load of fabric put in dyeing machines. The ratio of chemical usage is shown in Table A-3 in Appendix A. Total amount of chemical is consumed about 31 tons/month or 469 kg/ton of products. Three types of chemicals that use in large quantity per ton of products are sodium chloride (NaCl), sodium sulfate (Na2SO3) and hydrogen peroxide (H2O2), in the amount of 131 kg, 122 kg and 61 kg, respectively.

5.2.5 Material and Water Balance The account of inputs and outputs of material in operation unit defines the material

balance. Input materials are cotton yarn, water, steam, and chemicals. Figure 5.9 illustrates material balance, which modified from materials input in a day.

Figure 5.10 presents overall water balance, indicating total volume of water usage

is 369 m3/day. Wastewater is discharged to WWTP as 342 m3/day and unaccounted wastewater is 27 m3/day (7.9 %). According to the volume of wastewater is 130 m3 per ton of product. When compared with the standard norms in Table 5.4, this rate is in range of the standard value of Thailand, but less than standard published by World Bank and World Health Organization (WHO).

50

Outputs - Products 2,630 kg/d - Wastewater 342,000 kg/d Total 344,630 kg/d

Inputs - Cotton yarns 2,790 kg/d - Freshwater 343,000 kg/d

- Auxiliary Chemicals 1,062 kg/d - Dyestuff 14 kg/d - Steam 3,920 kg/d

Total 350,786 kg/d

Figure 5.9 Material Balance in Dyeing Process Water = 369

Input Unit: m3 /day

Dyeing = 327 Floor and Tools Cleaning* = 16 Sizing = 6 Domestic = 5 Resin tank cleaning = 2 Boiler = 6 Toilet, drinking, etc. = 7

Total = 369

Output

* 5% of total water consumption in dyeing process

Wastewater = 342

Total = 342

Unaccounted = 27 (7.9 %)

Figure 5.10 Overall Water Balance

51

Table 5.4 Comparison of wastewater generation to standard of Thailand (1999), WHO (1993) and World Bank (1997)

Standard available* (m3 /ton of product)

Type of factory Wastewater generation (m3 /ton of product)

Thailand (1999)

World Bank (1997)

WHO (1993)

Dyeing and finishing (Fabric only)

130

115.7-140

100-150

265

Source: *Kumar et al (1999) 5.2.6 Wastewater Flow Measurement

Figure 5.11 presents the estimated wastewater flow rate from each stage of dyeing process; refer to Table B-1 in Appendix B. Washing water is used highest of all (61%). Wastewater coming from dyeing section is combined in the sump tank. Table 5.5 shows the average wastewater flow rate is 342 m3/day and Figure 5.12 shows the variation of wastewater flow rate on three days. Wastewater flow rate is vary in each time, because of dyeing machines are not operated in the same time. The details of flow rate measurement are shown in Table B-3, B-4 and B-5 in Appendix B.

Dyeing Wastewater (327 m3/d)

Softening19 m3 (6%)

Des izing25 m3 (8%)

Scouring &Bleaching29 m3 (9%)

Dyeing25 m3 (8%)

Fixing 25 m3 (8%)

W ashing204 m3 (61%)

Figure 5.11 Estimate Daily Wastewater Flow rate

52

Table 5.5 Average of Wastewater Flow rate

Date Volume of bucket (L)

Flow rate (L/sec)

Flow rate (m3/day)

05/10/2001 17 5.27 341.40 20/10/2001 17 5.26 340.89 25/10/2001 17 5.30 343.61 Average 17 5.28 341.97

0

200

400

600

800

1000

1200

8.00 9.00 10.00 11.00 12.00 13.00 14.00 15.00 16.00 17.00 18.00 Time

Flow

rate

(m3/

d)

5/10/0120/10/0125/10/01

Figure 5.12 Variation of Wastewater Flow rate 5.2.7 Wastewater Characteristics from Dyeing Processes

Characteristics of wastewater drained from each step of the dyeing process are

given in Table B-1 and B-2 in Appendix B. The characteristics of wastewater generated from unit operations of desizing,

scouring, bleaching and washing I are 2,898-6,642 mg/L COD, 86-264 mg/L SS and 46 – 224 ADMI of color. This result indicates high concentration of pollutants in wastewater.

Wastewaters from dyeing and washing IV unit operations contain 249-664 mg/L

COD, 24-77 mg/L SS and 40-73 ADMI of color. From an observation, these processes produce strong colored wastewater. Therefore, the wastewater should be treated with proper chemical treatment before discharge into public canal.

Wastewaters from washing II and softening unit operations contain 454 - 843 mg/L COD, 68 - 82 mg/L SS, and 22 - 44 ADMI of color. This wastewater does not have strong color, however high value of COD and SS indicate high contamination. Therefore, should be treated with proper treatment system.

53

All of the results from data analysis show that the desizing, scouring, bleaching and washing I unit operations produce higher concentration of wastewater in term of COD and SS than other unit in cotton fabric dyeing process. Whereas, the unit operation of dyeing and washing IV produce strong colored wastewater. For washing III, V, VI and fixing, the quality of wastewater is better than other unit operations therefore it may be reused. If light colored wastewater is separated from strong colored wastewater, the volume of wastewater in sump tank and wastewater treatment plant can be reduced significantly. Moreover, it can reduce coagulant used in chemical treatment plant too.

5.3 Wastewater Segregation 5.3.1 Current status of segregation Wastewater from dyeing process is combined with colored wastewater and less colored wastewater causing high volume of wastewater discharged to wastewater treatment plant. As a result, treatments cost increases and on the other hand the efficiency of treatment decrease. 5.3.2 Proposal for better wastewater segregation Figure 5.13 shows the proposed of better wastewater segregation system, which wastewater will be separated into two streamlines. The amount of highly contaminated or colored wastewater (around 200 m3/day) will be treated by chemical treatment plant before it flows to biological treatment. While less contaminated or less colored wastewater can be directly discharged or reused. 5.4 Wastewater Quantities and Treatment Plant Efficiency Wastewater generated from the dyeing process is discharged continuously to the WWTP. Both colored and colorless wastewater is combined in sump tank. Table A-9 and A-10 in Appendix A show the characteristics of wastewater collected from streamline of WWTP. From Table 5.5, it can be seen that the total wastewater generated is average 342 m3/day. Problems were found during the study of WWTP efficiency is as follow: - No screening and as a result causing of pipe and pump blockage.

- Capacity of aeration tank is insufficient for wastewater. - The detention time of sedimentation is too short, therefore SS is not properly

removed - No paddle in slow and rapid mixing tank. - Out of secondary sedimentation tank. - No sludge treatment unit. - No coagulant used for chemical treatment. - Lack of daily monitoring, such as pH control.

54

Fig 5.13 segregation

55

Figure 5.14 shows wastewater characteristics in terms of BOD, COD, SS and color, indicating treatment efficiency of WWTP. The results show that the removal efficiencies vary in each unit. After the chemical treatment plant, efficiency is removing of BOD, COD, SS and colors are very low. When the first sedimentation tank treats wastewater, all parameters are less removed. This may be due to short detention time. After that wastewater passed the aeration tank, BOD, COD, and color are removed 55%, 46% and 33%, respectively. But SS is increased, because effluent is directly pumped to drainage channels. These effluents are not meeting the industrial effluent standard of Thailand in Table C-1 in Appendix C.

Flow: 342 m3/day BOD: 682 mg/L COD: 1648 mg/L SS: 150 mg/L Color: 233 ADMI

BOD: 601 mg/L (12 %) COD: 1524 mg/L (7.5 %) SS: 141 mg/L (6 %) Color: 177 ADMI (24 %)

BOD: 245 mg/L (55 %) COD: 788 mg/L (46 %) SS: 151 mg/L (0 %) Color: 45 ADMI (68 %)

Influent

Aeration tank

Sedimentation Tank

Slow mixing tank

Rapid mixing tank

Sump

Cooling Tower

Public canal

BOD: 543 mg/L (9.6 %)

COD: 1448 mg/L (5 %) SS: 138 mg/L (2 %) Color: 140 ADMI (21 %)

( ) % of removal efficiency

Sampling point

Figure 5.14 Removal Efficiency of BOD, COD, SS and Color of the WWTP 5.4.1 Proposed Modifications for WWTP Figure 5.15 shows the modify flow diagram of WWTP for dyeing wastewater of this factory. The recommendations for improvement of WWTP are as bellows:

(a) The wastewater stream will be segregated into less polluted and high polluted before go to WWTP. Less polluted wastewater will be directly discharged to the aeration or reusing tank, whereas highly polluted wastewater will be flowed to chemical treatment plant.

56

(b) Installation of coarse screen in the wastewater channel before flow to sump tank. To protect pipe and pump from blockage and also to reduce SS in effluent.

(c) Installation of paddles in rapid and slow mixing tank for properly mixing of wastewater with coagulant, and also to increase the flocculation.

(d) Improvement of the sand drying bed for sludge dewatering.

(e) Sludge from the sedimentation tank will be pumped to the sand drying bed. This is to prevent the accumulation of sludge in the tank that may effect the functioning of the tank.

(f) Improvement of the secondary sedimentation tank, and installation of pumps for sludge returning to the aeration tank. 5.4.2 Coagulation Dosage and Settleable Determination Many research studies have shown chemical treatment to be effective for removal of COD, color and suspended matter. Therefore, a lab scale treatment study was done in order to investigate the optimum conditions for this treatment operation. The wastewater treatment study was done for combined and highly polluted wastewater after segregation. Highly polluted wastewater was obtained by mixing effluent samples collected from the desizing, scouring, bleaching, dyeing and finishing stages. These were mixed in the same proportion as they are discharged during process. The following types of coagulants were used for the treatment of both types of wastewater:

1) Ferrous Sulfate 2) Ferrous Sulfate and Lime 3) Alum

Table D1-D6 in Appendix D show the result of Jar test by using each coagulant for

combined wastewater and wastewater after segregation. The result can be concluded as follows: Combined wastewater treatment: The optimum dose of Ferrous Sulfate was found to be 1800 mg/L, giving a COD reduction of 58.61 % but the determination of color was not possible due to oxidation of the supernatant. An optimum dose of 1000 mg/L of Ferrous Sulfate combined with an optimum dose of 800 mg/L of Lime gave 91.34 % reduction in color and 42.11 % reduction in COD. And also the optimum dose of 1800 mg/L of Alum gave 98.27 % reduction in color and 50 % reduction in COD. Highly polluted wastewater treatment after segregation:

57

The optimum dose of 2800 mg/L of Ferrous Sulfate gave a COD reduction of 56.41 %. An optimum dose of 2000 mg/L of Ferrous Sulfate combined with an optimum dose of 800 mg/L of Lime gave a color reduction of 90.74 % and COD reduction of 55.81 %. An optimum dose of 2600 mg/L of Alum gave 92.59 % of color and 49.61 % of COD reduction. Percentage of the removal indicate that treatment of high-polluted wastewater with Ferrous Sulfate give much greater COD reduction, and Alum gives much greater color reduction. Fig 5.15 Modify WWTP

58

Figure 5.16 and 5.17 presents the jar test result using alum for combined and after

segregation wastewater. The result is indicating an optimum dose of alum and percentage reduction of COD and color.

Table 5.6 presents the treatment cost with and without stream segregation. There is difference treatment cost of each coagulant using, and alum cost is the cheapest. Treatment with alum gives 92-98 % reduction of color and 49-50 % of COD reduction. Therefore, it can be said that treatment with alum is an optimum with respect to efficiency and treatment cost.

The settleable solids were measured in order to compare the quantity of sludge production, from treatment of combined and highly polluted wastewater with different coagulants present in Table D-7 in Appendix D. In both condition, treatment with Ferrous Sulfate produced the least amount of sludge. In contrast, treatment with Alum produced the largest amount of sludge.

0

20

40

60

80

100

120

1200 1400 1600 1800 2000 2200 2400 2600Alum dosage (mg/L)

Perc

enta

ge re

duct

ion

ColorCOD

Figure 5.16 Jar Test Result using Alum for Combined Wastewater

59

0

20

40

60

80

100

120

1200 1400 1600 1800 2000 2400 2600 2800 3000Alum dosage (mg/L)

Perc

enta

ge re

duct

ion

ColorCOD

Table 5.6 Comparison of Wastewater Treatment Cost with and without Stream Segregation Figure 5.17 Jar Test Result using Alum for Wastewater after Segregation

For combined wastewater

Volume = 342 m3/day

Coagulant Dosage (mg/L)

COD Removal

(%)

Color Removal (%)

Cost* (Baht/ m3)

Cost* (Baht/d)

Saving** (Baht/yr.)

Ferrous sulfate 1800 58.61 - 32.4 11,081 Ferrous sulfate + Lime

1000+800 42.11 91.34 24.4 8,345

Alum 1800 50.00 98.27 7.2 2,462

For highly polluted wastewater after segregation Volume = 200 m3/day

Ferrous sulfate 2800 56.41 - 50.4 10,080 300,240 Ferrous sulfate + Lime

2000+800 55.81 90.74 40.4 8,080 79,440

Alum 2600 49.61 92.59 10.4 2,080 114,720 *Cost calculated on the basis of the following prices: Ferrous sulfate = 18 B/kg Lime = 8 B/kg Alum = 4 B/kg **300 days per year and the cost of flocculants used and sludge dewatering and disposal are not taken into account. 5.5 Air and Noise Pollution in the Workplace

60

5.5.1 Airborne Particulate Matter In this study, airborne particulate matter was measured in six areas as below.

(1) Spinning and warping section (2) Drying section (3) Weaving section (4) Sizing section (5) Cutting and sewing section (6) Dyeing section

Table D-8 in Appendix D shows the result of airborne particulate matter in term of

total dust in workplace of the factory. Table 5.7 presents the concentration of airborne particulate matter in each section.

Table 5.7 Concentration of Airborne Particulate Matter of Various Areas

Area/section 23/11/01

(mg/m3 ) 24/11/01 (mg/m3 )

Average Total dust (mg/m3 )

Spinning/warping 2.16 2.08 2.12 Drying 2.06 1.67 1.85 Weaving 2.67 2.92 2.79 Sizing 2.50 2.41 2.45 Cutting/sewing 0.83 1.08 0.95 Dyeing 1.25 1.50 1.36

All the values given in the table are less than the standard levels, when compared

with standard for average amount of inert or nuisance dust generated throughout the normal working time is 15 mg/m3. However, from the eco-mapping study, the factory is facing cotton dust problem. Cotton dust is prevalent in the textile industry and causes Byssinosis, which occurred mainly in worker. It is difficult to clean and collect. Therefore, the factory should have schedule to clean and collect this cotton dust several times a day. The mask should be provided for worker.

5.5.2 Noise Measurement

All areas of this factory were measured noise level, in term of dB (A) unit. According to noise level standards for workplace announced by the Ministry of Interior of Thailand, occupational exposure must not exceed 90 dB (A) for 7-8 hours/day and 80 dB (A) for more than 8 hours/day. (See Table C-2 in Appendix C)

Eco-mapping in Figure 5.4 indicates three areas where are main sources of noise pollution. After measurement seventy-six sampling points in plant, it found three areas have noise level exceed 80 dB (A), there are spinning, sizing, and dyeing section. Another once is weaving section, noise level is found to exceed 90 dB (A). Results of the noise level measurement of this factory are shown in Table D-9 in Appendix D.

61

Figure 5.18 shows the sampling points and their noise levels in term of dB (A). The

red areas are exposed to excessive noise level. Therefore, the counter measures should be undertaken as follow:

a) The workers should be provided with noise protection equipment such as Earplugs. b) Provide education and training for the worker.

c) Covering the part of equipment where generates noise pollution.

d) Reducing the exposure period for worker.

Fig 5.18 Noise

62

5.6 Chemical Substitution Dyestuffs are the only substances kept in storage room and handled by the workers in the color storage room. Other chemicals used in the dyeing processes are stored and handled in the area. This factory uses fourteen types of chemical, which are shown in Table A-4 in Appendix A. Two areas where chemical should be recovered and reused as below:

a) Reuse of dye solutions from the dye bath. b) Recovery of sizing agent in cotton processing.

Sizing agent can be recover from desizing effluents using technologies such as

ultra-filtration. Table 5.8 presents the chemical substitution is useful for reducing load of waste. In

this case, it can use synthetic warp sizes (based on PVA and acrylates) in place of the conventional starch based size preparations. Use Linear Alkyl Benzene Sulphonate (LABS) in place of soap that has benefits of both low BOD and good biodegradability. Use ammonium sulfate in place of acetic acid for pH adjustment in disperses dyeing. Although the salt concentration of the effluent would increase in this substitution, ammonium would serve as a nutrient in the biological treatment process. Table 5.8 Substitutions of Chemical and Advantage

Factory used Substitutions

Advantage

Starch

Synthetic warp sizes BOD reducing by 45 % in cotton sizing operation.

Soap Low BOD synthetic detergents

BOD reducing by 120 %

Acetic acid Formic acid

BOD reducing by 81 % in dye baths

63

Soda Ash Sodium acetate For neutralizing scoured goods so as to convert mineral into volatile organic acidity.

Acetic acid Ammonium sulphate/ Chloride/ Mineral acids

BOD reducing by 33-62 %

Source: UNEP (1994)

However, the substitutions of low BOD process chemicals for high BOD, which have two drawbacks, firstly, the increased cost usually associated with the low BOD products. Secondly, while these chemicals have low BOD values, should be known about their long-term biodegradability. 5.7 Energy Audit and Heat Loss 5.7.1 Boiler Efficiency

This factory use fire tube boiler and produced steam is used in dyeing, dryer and sizing section. From observation the boiler, blow down rate is about 100 L/d. TDS of wastewater is very high (7,916 mg/L) that is due to the low rate of blow down. Therefore, the blow down rate should be increased for reducing TDS value and as well as to protect boiler scaling.

Steam pipe is not insulated about ten meters long, causing heat loss 83.6 MJ/day. If there are insulated, the energy can be saved 63.5 MJ/d (75.9 %). Condensate pipes diameter 1½ inch two hundred meters, and diameter 2½ inch fifty meters including the feed water tank are not insulated which causing heat loss. If there are insulated, energy can be saved. Table 5.9 presents the amount of heat loss and the energy saving by insulation. The heat loss calculation is shown in Appendix E. Table 5.9 Heat Loss from Not insulated and Insulated of Pipes and Tank

Heat Loss Reduced

Item

Length/Area

Not insulated

(MJ/d)

Insulated (MJ/d)

(MJ/d) (%) Steam pipe diameter 3 inch

10 m 83.6 20.1 63.5 75.9

Condensate pipe diameter 1½ inch

200 m 980.2 365.7 614.5 62.7

Condensate pipe diameter 2½ inch

50 m 234.1 91.9 142.2 60.7

Feed water Tank 7.41 m2 264.3 117.4 146.9 55.6 Storage Tank 0.43 m2 20.4 6.8 13.6 66.6

Total 1582.6 601.9 980.7 62

64

5.7.2 Energy Conservation

The insulation of steam pipes, condensate pipes and feed water tanks are important for two purposes at the same time, energy conservation and safety of working conditions. The estimated reduction of heat loss due to insulation is 62 % of heat loss through the pipe.

This plant has fifteen steam traps. When stream drain is generated, the steam traps

are required to release stream drain. Steam drain should be immediately discharged and completely replaced with steam. Facilities using steam should be completely filled with steam in order to get optimal ability of the facilities.

Heat transfer losses caused by leaking system traps currently account for 10-15 %

of energy costs (Angsumalee,1999). Leaking in steam traps result is not only waste energy, but also inefficient heating, and cause damage to steam lines, valves, fitting and other equipment. Workers should be trained in the operation of steam trap testing equipment, and a presentative plan for the maintenance of steam traps should be developed. 5.8 Water Pinch Analysis Water pinch analysis was used as a guide to water and effluent management in dyeing process of this factory. Dyeing process has eleven stages as listed in Table 5.10. COD is considered as contaminant to use as input data in MatLab program. After put all data through program, then eliminating and grouping data without any conflicts. Table 5.11 presents the group classifying.

Table 5.10 Initial Input Data for Dyeing Process

COD (mg/L) Sample No.

Discription Flowrate(m3/d) Cmin Cmax

1 Desizing 25 120 3952 2 Scouring/Bleaching 29 120 5075 3 Washing I 34 120 3059 4 Washing II 34 0 708 5 Dyeing 25 0 412 6 Washing III 34 0 98 7 Washing IV 34 0 659 8 Washing V 34 0 173 9 Washing VI 34 0 79 10 Fixing 25 0 89 11 Softening 19 0 563

Table 5.11 Group Data Classifying

Group Processes Flow rate COD (mg/L)

65

(m3/d) Cmin Cmax

I Desizing Scouring/Bleaching Washing I

25 29 34

120 120 120

3952 5075 3059

II

Washing II Dyeing Washing IV Softening

34 25 34 19

0 0 0 0

708 412 659 563

III

Washing III Washing V Washing VI Fixing

34 34 34 25

0 0 0 0

98 173 79 89

I

III

II

88 (3968)

88 (111)

127 (0)

127 (111)

112 (0)

112 (602) 39 (111) Figure 5.19 Initial result of three groups from Matlab program 239 (0)

127 (0) 112 (0)

10 6 5 9 11 8 7 4

1 3 2

127 (111)

88 (111)

34 (0)

34 (708)

34 (0) 34 (0) 34 (0) 25 (0) 25 (0) 34 (0) 19 (0)

34 (111)29 (111) 25 (111)

34 (98) 34 (173) 34 (79) 25 (89) 19 (563)25 (412) 34 (659)

66

112 (602)

25 (3943) 34 (3050)29 (5066) 39 (111)

88 (3968)

239 (1761)

Figure 5.20 Result of all for three groups (The values in brackets are concentration, mg/L and without brackets are flow rate, m3/d)

Fig 5.21

67

Figure 5.19 shows the initial result of four groups that were classified by Water

Pinch Technology program. The final results for dyeing process with flow rate consideration is shown in Figure 5.20, only 239 m3 /day of freshwater is needed from the initial freshwater needed 327 m3 /day. That means 26 % of freshwater can be saved.

Figure 5.13 presents the schematic diagram of proposed stream segregation in

dyeing processes. This cases both the value of COD and color was considered to segregation study. Wastewater can be segregated into two streams, less polluted (127 m3 /day) that can be directly discharged to public canal, and highly polluted (200 m3 /day) that were sent to the WWTP. Whereas, water pinch analysis was used to guide water and wastewater management. The result presents wastewater about 88 m3 /day can be reused in desizing, scouring, bleaching, and washing I unit operations, and also remaining water reused can be used for floor and tools cleaning too. The result of this study is shown in Figure 5.21. When wastewater is reused, the freshwater consumption will be decreased, on the other hand, this system need to install the pump, which causes to increase electricity consumption. 5.9 Wastewater Minimization Options The reduction of wastewater generation in the factory can be identified into two ways as below:

a) Internal water reused in dyeing processes b) High pressure cleaning system

More than 50% water conservation is possible from the proper use of high-pressure

cleaning system (Joshi, 1997). Spray gun will be used for floor, tools and hand washing.

Table 5.12 Wastewater Minimization Options

Options

Existing wastewater

Generation (m3/yr.)

Wastewater after Modification

(m3/yr.)

Expected Reduction (m3/yr.)

68

Water reused - For desizing, scouring and bleaching

98,100

71,700

26,400

High pressure cleaning system - Floor, equipment, tools and hand washing

4,800

2,400

2,400

Total

102,900

74,100

28,800

5.10 Economical Feasibility Evaluation Economical feasibility evaluation shows the investment cost, annual saving cost and payback period. Table F-1 to F-3 in Appendix F is shown economic feasibility analysis for each option. The results of economic evaluation are shown in Table 5.13. Table 5.13 Economical Feasibility Evaluation for Waste Minimization measure with

Payback Period

Description Investment Cost (Baht/year)

Annual Saving Cost (Baht/year)

Payback Periods (Year)

Installation of water reused system

68,500

158,062

0.44

Insulation of pipes and tanks

207,640

31,609

6.57

Installation of high pressure cleaning system

4,500

14,700

0.31

69

Chapter 6

Conclusions and Recommendations

In this study, the conclusions and recommendations for waste and energy minimization at the factory can be developed as below: 6.1 Waste Audit in Plant

Eco-mapping is a tool for wastes auditing in plant of the factory in term of

surrounding environment, energy, solid waste, noise and dust, water and wastewater. Some suggestions to improve its present status are as follows:

6.1.1 Water and Wastewater Minimization a) Good operating practices: Schedule for the production process should be prepared in advance. As a result, the frequency in cleaning the equipment and the generating wastewater can be reduced. For example in dyeing process, light color should be scheduled prior to dark color. b) Onsite reuse: Reuse of washing wastewater III, V, VI and fixing to desizing and bleaching stages. The freshwater can be saved 88 m3/day, and also the volume of wastewater can be reduced the same. c) High pressure cleaning system: Spray gun should be used for floor, tools and hand cleaning. Water using is reduced around 50 % of total using. 6.1.2 Energy Conservation

a) Insulation of all steam and condensate pipes, feed water tank and condensate storage

tank. Result is 62% energy saving from heat loss through pipes. b) Recovery of all condensate to feed water tank. It can save energy for boiler preheating. c) Installation of power meters for each section and regular monitoring of power

consumption. d) Replacement or interchange of over size pumps and motors with the most optimum

size. e) Installation of proper steam traps for each steam line as well as set up the maintenance

plan. 6.1.3 Noise and Dust Control

From seventy-six sampling points, the noise level in weaving section is higher than noise level standard in workplace of Thailand. Therefore, earplugs must be provided for worker in plant area.

From six sampling points, the concentration of the particulate matter (total dust) in

plant is less than Thailand standard. However, cotton dust was found to disperse in all areas, therefore good plan for collecting and cleaning the cotton dust should be prepared.

70

6.2 Water Pinch Analysis The result of water pinch analysis indicates the possibility for internal water reused in dyeing processes. Only 239 m3/d of freshwater is needed from the initially used 327 m3/d. It means that 88 m3/d of wastewater can be reused in the process and the consumption of freshwater can be saved about 26 %. 6.3 Wastewater Treatment Plant Dyeing process has the potential of reducing wastewater treatment load by proper stream segregation. After the implementation of proper stream segregation, volume of wastewater to WWTP can reduce to 127 m3/d. Treatment of highly polluted wastewater after segregation with alum was found to be economical and efficient as compared to other coagulants. The recommendations for improving the WWTP are as follows: a) Segregation of wastewater into less polluted and highly polluted before treatment. b) Installation of screen for solid waste separation before discharge to sump tank. This can

protect pump and pipes from blockage. c) Improving the slow and rapid mixing tank by installation of motors and paddles for

mixing. d) Improvement of sedimentation and effluent tanks for proper settling. e) Improvement of sand drying bed for sludge dewatering. 6.4 Recommendations for Further Studies a) To study the suitability of effluent treatment for high quality of water such as Reverse

Osmosis and Ultra-filtration for the removal of color. b) To perform detailed design and cost for the proposed WWTP. c) To study the complete economic analysis for the proposed waste and energy

minimization options. d) To study the suitability method of cotton dust control and disposal. e) To study the recovery of energy from hot wastewater using heat exchangers.

71

References Angsumalee, C., 1999. A study on Cleaner Production in the industrial sector. Special study. AIT, Thailand. APHA-AWWA-WPCF, 1989. Standards methods for the Examination of Water and Wastewater. 17th ed. Barclay, S.T., and Buckley, C.A., 1998. Waste Minimization and effluent Treatment Guide: A publication for Textile industry. <URL:ftp//www.und.ac.za/und/prg/publications/textguide 1h.html> Bishop, L.P., 2000. Pollution Prevention: Fundamentals and Practice. Singapore: McGraw-Hill. Boonkasem, P., 2000. Application of Water Pinch Analysis for Rational water and Effluent management in Industry. Thesis no. EV-00-11. AIT, Thailand. Ciardelli, G. and Ranieri, N., 1997. Water Recycling in The Textile Industry: Several Case Studies. Italy. <URL:ftp://www.technotex.rete.toscana.it…20IN%20 THE20% TEXTILE%20INDUSTRY.htm> Correia, M.V., Stephenson, T., and Judd, J.S., 1994. Characterization of textile wastewaters – A review. Environmental Technology 15:917-929. CPIE, 1998. Samut Prakarn Cleaner Production for Industrial Efficiency Program, report. Pollution Control Department, Bangkok, Thailand. Economopoulos, 1993. Assessment of sources of Air, Water, and Land Pollution. A Guide to Rapid Source Inventory Techniques and Their Use in Formulating Environmental Control Strategies. WHO, Environmental Technologies Series, Part I, Geneva. Honda, A., and Yamamoto, O., 2000. Reduction of Industrial wastewater at minimized investment: Section 5 Dyeworks Industries. Global Environment Centre Foundation (GEC), Japan. <URL:ftp://nett21.unep.or.jp/CPT_DATA/English/RIW-web-E/RIW512-e.html> Hussain, N., 1994, Cleaner Production in the dyeing industry. Thesis no. EV- 94-13. AIT, Thailand. Janesiripanich, A., 1995. Waste Auditing in a Rice Cracker Factory. Thesis no. EV-95-2. AIT, Thailand. Kovals, J., 1999. Integrated Pollution home page: Textile Industry. IPPC home page BAT notes. <URL:ftp://www.varam.gov.lv/EIN/Pollution/batnotes/Etekstils.htm> Koottatep, T., 1993. Color Removal from Textile Finishing Wastewater. Thesis no. EV-93-12. AIT, Thailand.

72

Kumar, S., Visvanathan, C., and Priambodo, A., 1999. Energy and Environmental Indicators in the Thai Textile Industry. University of Technology, Sydney (UTS), Australia and Asian Institute of Technology (AIT), Thailand. Miyamoto, Y., 1996. Energy Conservation Note on Steam-Related Facilities. Environment and Natural Resources Management Division, ESCAP. United Nations. NC DEHNR, 1993. Industrial Pollution Prevention Program: Water Conservation for Textile Mills. Department of Environment, Health, and Natural Resources. Raleigh, North Carolina. <URL:ftp://www.p2pays.org/ref/01/00026.htm> Nemerow, N. L., 1978. Industrial water pollution: Origins, Characteristics and Treatment. USA: Addison-Wesley. Nemerow, N.L., 1995. Zero Pollution for Industry: waste minimization through industrial completes. USA: John Wiley & Sons, Inc. Thailand Environment Institute, Federation of Thai Industry, and Danish Cooperation for Environment and Development, 1998. Case study: Cleaner Technology in Thai Industry. Bangkok, Thailand Environment Institute. UNEP, 1994. The Textile Industry and The Environment. United Nations Publication. Technical report series No. 16. UNEP/IE – UNIDO, 1991. Audit and reduction Manual for Industry Emission and Waste. United Nations Publication. Technical report series No. 7. Visvanathan, C., Dang Quoc Tuan, N. T. Lien Ha, and Yamuna Alles, 1994. Wastewater Audit in Textile Dyeing Industry: A Case Study. Project on Industrial Pollution Control Applications for Small & Medium Scale Industries (IPCA), CDG-SEAPO, AIT, Thailand Visvanathan, C., 2001. ED09.21 Industrial Wastewater Pollution & Control: Industrial wastewater reuse. Urban Environmental Engineering Program, AIT, Thailand. Visvanathan, C., and N.T. Lien Ha, 1994. Waste minimization: an effective pollution abatement tool for small and medium scale industries. TEI Quarterly Environment 2: 40-52. Wang, Y. P., and smith R., 1994. Wastewater Minimization, Chemical Engineering Science 49:981.

73

74

Appendix A Data Information from the Factory

75

Figure A-1

76

Table A-1 Raw Material, Water, Energy and Products in 2001

Month

RM

(ton)

Fabrics

(ton)

Products

(ton)

GW

(m3)

Water Supply

(m3)

Electricity

(kWh)

Fuel oil

(L) January 50.89 57.77 8924 494 91000 36000

Febuary 59.52 57.29 8668 502 106000 48000

March 68.97 67.56 8974 444 123000 48000

Appirl 50.25 47.08 8186 520 98000 36000

May 67.69 67.19 8846 518 122000 60000

June 63.95 63.66 8690 508 115000 48000

July 64.41 66.30 8710 585 130000 48000

August 74.92 73.74 8852 580 123000 48000

September 72.31 68.88 8788 581 129000 60000

October 71.08 75.61 8978 581 128000 48000

November 73.25 73.98 8930 553 131000 60000

December 71.56 70.38 8968 536 137000 60000

Total 835.77 789 789 105514 6402 1433000 600000

Unit/Month 69.65 65.73 65.79 8793 534 119417 50000

Unit/day 2.79 2.63 2.63 352 18 4777 2000

77

Table A-2 Material Input per Batch for Dyeing Machine (Result 100% capacity per batch)

Winch Fong

Load: 180 kg Load: 240 kg Load: 300 kg Load: 420 kg

Operation (Kg) (Kg) (Kg) (Kg)

1. Desizing

Water 2000 2500 3000 3200

Enzyme 1.5 1.5 2.5 3

Soaping agent 1 1 1.5 1.8

2. Scouring and Bleaching

Water 2500 2500 3200 3200

NaCl 5 5 6 9

Brightening agent 0.5 6.5 0.72 0.96

Soaping agent 1 2 2 3

Hydrogen peroxide 12 14 16 21

NaOH 4.5 5 6 8

Sodium phosphate 5 5 6 9

3. Washing I

Water 3000 3000 3600 3600

4. Washing II

Water 3000 3000 3600 3600

Reyonets 0.2 0.3 0.3 0.4

5. Dyeing

Water 2000 2500 3200 3200

Dyestuff 0.040-6.0

Dispersing agent 1 1 0.5 0.5

Soda Ash 1 10.0-30 10.0-35.0 14-50

NaOH 1 1.0-3.0 1.5-3.5 1.4-4.5

Na2SO4 25 30-150 30-170 40-215

Sodium phosphate 1 1 2 2

6. Washing III

Water 3000 3000 3600 3600

7. Washing IV

Water 3000 3000 3600 3600

Soaping agent 0.3 0.5-1.0 0.4-1.0 0.5-1.0

Acetic acid 0.5 0.5-3.5 0.5-1.5 0.5-6.5

8. Washing V

Water 3000 3000 3600 3600

9. Washing VI

Water 3000 3000 3600 3600

10. Fixing

Water 2000 2000 3200 3200

Fixing agent 0.2 1.8 0.4-0.7 0.5-1

11. Softening

Water 1500 1500 2500 2500

78

Softener agent 1.5 2 1.8-2.0 2

Table A-3 Water and Chemicals used in Dyeing Machine per Batch

Winch Fong

Load :180 kg Load: 240 kg Load: 300 kg Load: 420 kg

(kg) (kg) (kg) (kg)

Water (L) 28000 29200 36500 37200

Enzyme 1.5 1.5 2.5 3

Soaping agent 2.3 4 4.5 5.8

NaCl 5 5 6 9

Brightening agent 0.5 6.5 0.72 0.96

H2O2 12 14 16 21

NaOH 5.5 6.0-8.0 7.5-9.5 9.4-12.5

Na2SO4 25 30-150 30-170 40-215

Sodium phosphate 6 6 8 11

Reyonets 0.2 0.3 0.3 0.4

Dispersing agent 1 1 0.5 0.5

Soda ash 1 10.0-30.0 10.0-35.0 14-50

Acetic acid 0.5 0.5-3.5 0.5-1.5 0.5-6.5

Fixing agent 0.2 1.8 0.4-0.7 0.5-1.0

Softening agent 1.5 2 1.8-2.0 2

Dyestuff 0.04-6.0

79

Table A-4 Estimate Chemicals Consumption in Production Processes

No.

Type of chemicals

Quantity

(ton/year)

Quantity

(kg/month)

Quantity

(kg/ton of products)1 Sodium Chloride (NaCl) 103.68 8640 131.33

2 Sodium Sulfate (Na2SO3) 96.00 8000 121.60

3 Hydrogen Peroxide (H2O2) 48.36 4030 61.26

4 Soda Ash (Na2CO3) 30.00 2500 38.00

5 Starch 24.00 2000 30.40

6 Soaping agent 20.40 1700 25.84

7 Caustic Soda (NaOH) 18.41 1534 23.32

8 Wax 12.00 1000 15.20

9 Softening agent 6.00 500 7.60

10 Dyestuff 4.20 350 5.32

11 Acetic Acid (CH3COOH) 2.18 182 2.77

12 Dispersion agent 1.92 160 2.43

13 Glue 1.92 160 2.43

14 Fixing agent 1.20 100 1.52

Total 370.27 30856 469.01

80

Table A-5 The Production Activity Schedule of the Factory

Section No.of Working time No. of Shift No. of worker

Office 8 1 8

Spinning and warping 8 1 10

Clump thread 8 1 8

Sizing 16 2 4

Weaving 24 3 23

Dyeing 16 2 12

Drying 8 1 10

Sewing/deocorate 8 1 23

Maintenance 8 3 11

Fix brandname 8 1 7

Inspecting/scenting 8 1 11

Packaging 8 1 12

Transportation 8 1 8

Warehouse 8 1 3

Remark: Not include over time working

81

Appendix B Water and Wastewater Characteristic

82

Table B-1 Wastewater Analysis Results (Winch machine, Load: 180 kg) (Sample collected on 5th October 2001) Sample

No.

Discription Flow

(m3/d)

pH Temp.

0C

Turb.

(NTU)

COD

(mg/L)

SS

(mg/L)

Color

(ADMI)1 Desizing 25 8.18 89 122 3692 264 186

2 Scouring &Bleaching 29 11.00 92 155 3507 230 122

3 Washing I 34 10.31 45 47 2898 128 46

4 Washing II 34 9.68 37 29 572 69 44

5 Dyeing 25 10.96 73 15 249 49 73

6 Washing III 34 10.36 42 8 99 39 16

7 Washing IV 34 9.17 90 16 655 24 40

8 Washing V 34 7.83 47 3 159 20 18

9 Washing VI 34 7.51 37 4 100 37 17

10 Fixing 25 7.52 34 3 125 35 3

11 Softening 19 6.02 34 20 454 77 22

Table B-2 Wastewater Analysis Results (Winch machine, Load: 180 kg)

(Sample collected on 26th November 2001)

Sample No.

Discription

Flow

(m3/d)

pH Temp.

0C

Turb.

(NTU)

COD

(mg/L)

SS

(mg/L)

Color

(ADMI)1 Desizing 25 8.08 90 130 4212 153 198

2 Scouring &Bleaching 29 11.24 82 150 6642 125 224

3 Washing I 34 10.47 42 47 3220 86 58

4 Washing II 34 9.63 35 27 843 68 36

5 Dyeing 25 10.46 56 18 575 77 56

6 Washing III 34 10.06 36 9 97 54 10

7 Washing IV 34 10.12 93 18 664 71 65

8 Washing V 34 9.58 48 4 186 35 15

9 Washing VI 34 8.82 36 4 58 33 11

10 Fixing 25 8.04 33 4 52 31 4

11 Softening 19 5.77 34 2.4 672 82 30

83

Table B-3 Wastewater Flowrate Measurment by Bucket and Stopwatch Method

(Measured on 5th, Oct. 2001)

Duration (Second) Flowrate Time Volume (L) 1 2 3 Average (L/sec) (m3/d)

8.00 17.0 8.5 8.03 8.48 8.34 2.04 132.14 9.00 17.0 13.77 14.21 14.18 14.05 1.21 78.39 10.00 17.0 12.56 12.45 11.45 12.15 1.40 90.64 11.00 17.0 1.45 1.44 1.47 1.45 11.70 757.98 12.00 17.0 1.5 1.54 1.55 1.53 11.11 720.00 13.00 17.0 1.35 1.51 1.52 1.46 11.64 754.52 14.00 17.0 7.45 7.5 7.54 7.50 2.27 146.95 15.00 17.0 15.1 17.08 16.01 16.06 1.06 68.58 16.00 17.0 1.56 1.78 1.7 1.68 10.12 655.71 17.00 17.0 9.44 9.46 9.41 9.44 1.80 116.74 18.00 17.0 4.43 5.05 4.66 4.71 3.61 233.72

Average 5.27 341.40 Working time per day is 18 hours (07.00am to 01.00pm) Wastewater flowrate = 341.40 m3 per day

Table B-4 Wastewater Flowrate Measurment by Bucket and Stopwatch Method (Measured on 20th, Oct. 2001)

Duration (Second) Flowrate Time Volume

(L) 1 2 3 Average (L/sec) (m3/d) 8.00 17.0 8.46 8.6 8.03 8.36 2.03 131.72 9.00 17.0 15.8 16.03 15.18 15.67 1.08 70.30 10.00 17.0 1.02 1.18 1.08 1.09 15.55 1007.56 11.00 17.0 3.56 3.13 3.57 3.42 4.97 322.11 12.00 17.0 4.8 4.84 4.95 4.86 3.50 226.51 13.00 17.0 8.35 8.45 7.54 8.11 2.10 135.78 14.00 17.0 1.8 1.82 1.96 1.86 9.14 592.26 15.00 17.0 2.09 2.04 2.1 2.08 8.19 530.47 16.00 17.0 5.03 5.41 5.77 5.40 3.15 203.87 17.00 17.0 4.5 4.83 4.32 4.55 3.74 242.11 18.00 17.0 3.89 3.91 3.71 3.84 4.43 287.12

Average 5.26 340.89 Working time per day is 18 hours (07.00am to 01.00pm) Wastewater flowrate = 340.89 m3 per day

84

Table B-5 Wastewater Flowrate Measurment by Bucket and Stopwatch Method

(Measured on 25th, Oct. 2001)

Duration (Second) Flowrate Time Volume (L) 1 2 3 Average (L/sec) (m3/d)

8.00 17.0 7.66 7.32 7.43 7.47 2.28 147.47 9.00 17.0 2.06 1.9 2.25 2.07 8.21 532.17 10.00 17.0 12.93 13.34 12.53 12.93 1.31 85.18 11.00 17.0 7.08 7.27 7.44 7.26 2.34 151.67 12.00 17.0 1.27 1.21 1.2 1.23 13.86 898.04 13.00 17.0 1.45 1.49 1.34 1.43 11.92 772.15 14.00 17.0 4.99 5.48 5.88 5.45 3.12 202.13 15.00 17.0 2.58 2.55 2.28 2.47 6.88 445.99 16.00 17.0 10.89 9.92 9.85 10.22 1.66 107.79 17.00 17.0 12.07 11.45 11.15 11.56 1.47 95.32 18.00 17.0 3.2 3.21 3.26 3.22 5.27 341.76

Average 5.30 343.61 Working time per day is 18 hours (07.00am to 01.00pm) Wastewater flowrate = 343.61 m3 per day

85

Table B-6 Wastewater Analysis Result (WWTP) (Sample collected on 27th Sept. 2001)

Sample No.

Discription

pH Temp

0C

Cond.

(mS/cm)

Turbidity

(NTU)

BOD

(mg/L)

COD

(mg/L)

TDS

(mg/L)

SS

(mg/L)

Color

(ADMI)

Total Cr

(mg/L)

Cr (VI)

(mg/L) 1 Sump tank 10.44 45 15.78 73 584 1477 9472 132 182 0.597 0.217

2 Mixing tank 10.16 40 12.75 46 680 1625 8008 130 70 - -

3 Sedimentation I 9.81 40 8.22 47 712 1476 5486 257 73 - -

4 Aeration tank 8.44 35 8.05 30 273 738 4642 234 51 - -

5 Effluent 8.28 30 8.07 28 210 726 4666 173 49 0.542 0.018

Table B-7 Wastewater Analysis Result (WWTP) (Sample collected on 26th November 2001)

Sample Discription pH Temp. Cond. Turbidity BOD COD TDS SS Color Total Cr Cr (VI)

No. C (mS/cm) (NTU) (mg/L) (mg/L) (mg/L) (mg/L) (ADMI) (mg/L) (mg/L)

1 Sump tank 10.21 42 16.67 91 680 1320 8655 168 153 - -

2 Mixing tank 10.09 40 14.21 52 523 1422 7503 152 84 - -

3 Sedimentation I 9.98 39 9.23 48 573 1520 5458 219 107 - -

4 Aeration tank 8.53 38 8.41 42 351 918 3995 198 62 - -

5 Effluent 8.08 29 8.01 30 279 850 2918 129 42 - -

86

Table B-8 Water Quality of the Factory ( Sample collected on 26 January 2002)

Sample

pH Temp.

0C

Turbidity

NTU

Total Hardness

mg/L as CaCO3

TDS

mg/L Tap water 7.28 31 2 51 336

Ground water 7.01 30 7.5 320 1726

Treated water 7.38 32 0.5 22 1258

Feed water 8.95 86 35 25 508

Blow down water 11.5 83 10 12 7916

Table B-9 Water Supply Record

Date

Start

End

Quantity

(m3/d) 22/10/01 19387 19405 18

23/10/01 19405 19424 19

24/10/01 19424 19444 20

25/10/01 19444 19463 19

26/10/01 19463 19480 17

27/10/01 19480 19497 17

Average 18.3

87

Appendix C Standard and Recommendations

88

Table C-1 Industial Effluent Standards in Thailand

Parameter Standard Values pH Value 5.5-9.0 Total Dissolved Solids (TDS)

Not more than 3,000 mg/L depending on type of receiving water or type of factory but, not exceeding 5,000 mg/L

Suspended Solids (SS) Not more than 50 mg/L depending on type of receiving water or type of factory but, not exceeding 150 mg/L

Temperature Not more than 40 C Color and Odour Not objectionable Sulfide (as H2S) Not more than 1.0 mg/L Cyanide (as HCN) Not more than 0.2 mg/L Fats oil and Grease (FOG) Not more than 5 mg/L depending on receiving water of type

of factory, but not exceeding 15 mg/L Formaldehyde Not more than 1.0 mg/L Phenols Not more than 1.0 mg/L Free Chlorine Not more than 1.0 mg/L Pesticides Not detectable BOD Not more than 20 mg/L depending on receiving water of type

of factory, but not exceeding 60 mg/L TKN Not more than 100 mg/L depending on receiving water of

type of factory, but not exceeding 200 mg/L

COD Not more than 120 mg/L depending on receiving water of type of factory, but not exceeding 400 mg/L

Heavy Metals 1. Zn Not more than 5.0 mg/L 2. Cr (+6) Not more than 0.25 mg/L 3. Cr (+3) Not more than 0.75 mg/L 4. Cu Not more than 2.0 mg/L 5. Cd Not more than 0.03 mg/L 6. Ba Not more than 1.0 mg/L 7. Pb Not more than 0.2 mg/L 8. Ni Not more than 1.0 mg/L 9. Mn Not more than 5.0 mg/L 10. As Not more than 0.25 mg/L 11. Se Not more than 0.02 mg/L 12. Hg Not more than 0.005 mg/L Source : Notification of the Ministry of Science, Technology and Environment,

No. 3 (1996), dated 3 January 1996

89

Table C-2 Noise Level Standards in Workplace

Noise Level (dBA)

Exposure Time (hour per day)

Remarks

91 Less than 7 Ear plugs or ear muffs should be

90 7 to 8 used if needed.

80 More than 8

140 Not allowed

Source: Laws and Standards on pollution control in Thailand, 4th edition (1997)

90

Appendix D Experimental Data

91

Table D-1 Jar Test Result Using Ferrous Sulfate for Combined Wastewater

Coagulants used = Ferrous Sulfate

Flocculant = Cat-Floc 2 ml/L Initial COD = 1325 mg/L Initial Color = non

Supernatant Coagulants

Dosage Color*

(ADMI) COD

(mg/L)

Color Removal

(%)

COD Removal

(%)

Sludge Volume

(ml)

1000 818.85 38.20 80 1200 721.73 45.53 80 1400 701.98 47.02 80 1600 620.63 53.16 90 1800 548.44 58.61 100 2000 557.95 57.89 100 2200 721.73 45.53 100 2400 718.28 45.79 100

*color can not be determined due to oxidation of the supernatant Table D-2 Jar Test Result Using Ferrous Sulfate for Wastewater after Segregation

Coagulants used = Ferrous Sulfate

Flocculant = Cat-Floc 2 ml/L

Initial COD = 2503 mg/L Initial Color = non

Supernatant Coagulants

Dosage Color*

(ADMI) COD

(mg/L)

Color Removal

(%)

COD Removal

(%)

Sludge Volume

(ml)

2000 2018 19.38 100 2200 1862 25.58 120 2400 1416 43.41 140 2600 1164 53.49 170 2800 1091 56.41 190 3000 1125 55.04 190 3200 1242 50.39 200 3400 1319 47.29 200

*color can not be determined due to oxidation of the supernatant

92

Table D-3 Jar Test Result Using Ferrous Sulfate + Lime for Combined Wastewater

Coagulants used = Ferrous Sulfate + Lime

Flocculant = Cat-Floc 2 ml/L Initial COD = 1325 mg/L Initial Color = 231 ADMI

Supernatant Coagulants Dosage (mg/L)

Ferrous Lime Color

(ADMI) COD

(mg/L)

Color Removal

(%)

COD Removal

(%)

Sludge Volume

(ml)

1000 400 28 957 87.88 31.58 120 1000 600 21 883 90.91 36.84 140 1000 800 20 810 91.34 42.11 150 1000 1000 22 857 90.48 35.32 140 1000 1200 23 854 90.04 35.54 150 1000 1400 29 957 87.44 31.58 140 1000 1600 25 957 89.17 31.58 140

Table D-4 Jar Test Result Using Ferrous Sulfate + Lime for Wastewater after Segregation

Coagulants used = Ferrous Sulfate + Lime

Flocculant = Cat-Floc 2 ml/L Initial COD = 2503 mg/L Initial Color = 270 ADMI

Supernatant Coagulants Dosage (mg/L)

Ferrous Lime Color

(ADMI) COD

(mg/L)

Color Removal

(%)

COD Removal

(%)

Sludge Volume

(ml)

2000 200 66 1474 75.55 41.09 200 2000 400 51 1455 81.11 41.86 200 2000 600 29 1125 89.26 55.04 230 2000 800 25 1106 90.74 55.81 260 2000 1000 28 1126 89.63 55.03 300 2000 1200 31 1164 88.52 53.49 280 2000 1400 41 1358 84.81 45.74 260

93

Table D-5 Jar Test Result Using Alum for Combined Wastewater

Coagulants used = Alum

Flocculant = Cat-Floc 2 ml/L Initial COD = 1325 mg/L Initial Color = 231 ADMI

Supernatant Coagulants Dosage (mg/L)

Color (ADMI)

COD (mg/L)

Color Removal

(%)

COD Removal

(%)

Sludge Volume

(ml)

1200 88 870 61.90 34.21 120 1400 57 766 75.32 42.11 150 1600 21 696 90.91 47.37 150 1800 4 661 98.27 50.00 220 2000 4 766 98.27 42.11 240 2200 18 800 92.21 39.47 230 2400 62 870 73.16 34.21 190 2600 71 939 69.26 28.95 180

Table D-6 Jar Test Result Using Alum for Wastewater after Segregation

Coagulants used = Alum

Flocculant = Cat-Floc 2 ml/L Initial COD = 2503 mg/L Initial Color = 270 ADMI

Supernatant Coagulants Dosage (mg/L)

Color (ADMI)

COD (mg/L)

Color Removal

(%)

COD Removal

(%)

Sludge Volume

(ml)

1200 152 1882 43.71 24.81 150 1400 126 1707 53.33 31.78 170 1600 104 1688 61.48 32.56 180 1800 86 1689 68.15 32.71 220 2000 56 1474 79.25 41.09 300 2400 34 1416 87.40 43.41 350 2600 8 1261 97.03 49.61 400 2800 20 1339 92.59 46.51 400 3000 19 1339 92.96 46.51 400

94

Sludge Dewaterbility Sludge Dewaterbility was determined for sludge obtained by treatment of wastewater with the optimum dose of each coagulant. The detailed calculations are as follows: Raw sludge quantity, Q (ton/day) = a m3/m3 * b m3/day * d kg/m3 * ton/1000 kg where, a = sludge volume per m3 of wastewater b = wastewater flow d = density,assumed as 1000 kg/m3 Dewatered sludge quantity (ton/day), assuming 60% water removal = Q* 0.4 Table D-7 Sludge Dewaterbility

For Combined Wastewater (Flowrate = 342 m3/day)

Coagulant Sludge volume

(m3/m3 ww) Sludge quantity

(ton/day) Dewatered sludge

(ton/day) Cost*

(Baht/day)

Ferrous Sulfate 0.10 34.20 13.68 20520

Ferrous Sulfate and Lime

0.15

51.30

20.52

30780

Alum 0.22 75.24 30.10 45144

For Highly Polluted Wastewater after Segregation

(Flowrate = 200 m3/day)

Coagulant Sludge volume (m3/m3 ww)

Sludge quantity(ton/day)

Dewatered sludge (ton/day)

Cost* (Baht/day)

Ferrous Sulfate 0.19 38 15.20 22800

Ferrous Sulfate and Lime

0.26

52

20.80

31200

Alum 0.40 80 32.00 48000

• Cost calculation based on industrial wastewater sludge disposal of GENCO Company's

price is 1,500 Baht/ton.

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Table D-8 Concentration of Airborne Particulate Matter of Various Areas

Area/section

Date

SamplingDuration

(Min)

Pump

Flowrate (L/Min)

Volumeof Air

(L)

Weight of PM (mg)

Concentration

(mg/m3)

Average(mg/m3)

23/11/01 60 2 120 0.260 2.16 Spinning/ warping 24/11/01 60 2 120 0.251 2.08

2.12

23/11/01 60 2 120 0.248 2.06 Drying 24/11/01 60 2 120 0.203 1.67

1.85

23/11/01 60 2 120 0.320 2.67 Weaving 24/11/01 60 2 120 0.352 2.92

2.79

23/11/01 60 2 120 0.301 2.50 Sizing 24/11/01 60 2 120 0.289 2.41

2.45

23/11/01 60 2 120 0.100 0.83 Cutting/ Sewing 24/11/01 60 2 120 0.132 1.08

0.95

23/11/01 60 2 120 0.153 1.25 Dyeing 24/11/01 60 2 120 0.180 1.50

1.36

96

Table D-9 Noise Level of Various Areas

Noise Level, dB(A) Noise Level, dB(A)No. Section 17/11/01 23/11/01

AveragedB(A)

No. Section 17/11/01 23/11/01

Average dB(A)

1 Drying 69.9 71.7 71 39 dyeing 83.0 82.3 832 70.5 72.2 71 40 82.1 81.3 823 70.6 70.6 71 41 81.0 81.2 814 77.5 74.7 76 42 82.6 82.5 835 Spinning 73.1 70.5 72 43 81.9 81.5 826 75.0 74.6 75 44 82.0 82.6 827 80.1 77.6 79 45 81.0 80.8 818 87.0 85.9 86 46 81.1 82.0 829 81.2 82.3 82 47 Boiler 81.0 82.0 82

10 80.0 80.5 80 48 78.4 76.6 7811 Warping 76.0 75.5 76 49 78.0 76.2 7712 79.7 77.3 79 50 83.2 82.4 8313 78.2 83.6 81 51 76.7 78.0 7714 77.0 78.2 78 52 Weaving 86.0 88.4 8715 76.8 78.7 78 53 85.1 86.0 8616 77.9 79.7 79 54 83.2 84.4 8417 78.1 79.3 79 55 90.2 89.8 9018 77.0 76.8 77 56 90.0 93.2 9219 76.0 78.1 77 57 92.5 93.7 9320 77.2 78.5 78 58 91.2 93.7 9221 73.3 75.1 74 59 89.9 91.7 9122 75.3 75.9 76 60 92.6 91.7 9223 Packaging 66.7 69.0 68 61 90.6 91.2 9124 64.2 62.9 64 62 90.0 93.0 9225 61.7 61.0 61 63 92.8 93.2 9326 Cut/Sew 64.6 66.0 65 64 92.4 92.1 9227 67.0 68.2 68 65 92.1 93.7 9328 74.0 75.1 75 66 92.6 93.5 9329 71.7 74.3 73 67 93.4 91.0 9230 74.1 70.9 73 68 92.4 93.5 9331 79.8 82.6 81 69 92.6 92.7 9332 Sizing 80.1 80.3 80 70 90.4 92.7 9233 81.6 82.7 82 71 92.2 92.0 9234 77.0 78.0 78 72 90.2 91.0 9135 78.9 78.6 79 73 91.0 90.3 9136 80.3 79.6 80 74 90.6 90.3 9037 81.2 80.4 81 75 91.6 92.8 9238 81.0 82.8 82 76 91.5 93.1 92

97

Appendix E Heat Loss Calculation

98

Heat Loss Calculation1 1) Uninsulated steam pipes - Steam pressure: 5 kg/cm2

- Steam pipe diameter: 3 inches - Ambient temperature: 28 0C - Surface temperature of pipe: 108 0C - Length of pipe: 10 meters - Working time: 8 h/d

As the difference between the surface temperature of the pipe and ambient

temperature is 108 – 28 = 80 0C and nominal size of the pipe is 3 inches, the heat loss is around 250 kcal/m.h as shown in Fig E-1.

Heat loss = 250 kcal/m.h * 10 m * 8 h/d = 20,000 kcal/d (83.6 MJ/d) Heat loss of an insulated pipe, surface temperature of pipe is 48 0C. As the difference between the surface temperature of the pipe and ambient temperature is 48 – 28 = 20 0C

Heat loss = 60 kcal/m.h * 10 m * 8 h/d = 4,800 kcal/d (20.1 MJ/d) According to the energy can be saved (83.6 – 20.1) = 63.5 MJ/d (75.9 %) 2) Uninsulated condensate pipes Drying section (A)

- Condensate pipe diameter: 1½ inches - Length of pipe 1½: 110 meters - Surface temperature of pipe: 95 0C - Working time: 8 h/d For A, the difference temperature is 95-28 = 67 0C and nominal size of the pipe is

1½ inches, the heat loss is around 110 kcal/m.h. Heat loss = 110 kcal/m.h. * 110 m * 8 h/d = 96,800 kcal/d (404.6 MJ/d) If the pipe is insulated, estimate surface temperature is 50 0C. As the difference between surface temperature of the pipe and ambient temperature is 50-28 = 22 0C, the heat loss is around 35 kcal/m.h.

1 Miyamoto, Y. (1996), Energy Conservation Note on Steam-Related Facilities. Environment and Natural Resources Management Division. ESCAP, United Nations.

99

Heat loss = 35 kcal/m.h. * 110 m * 8 h/d = 30,800 kcal/d (128.7 MJ/d Therefore, the energy can be saved (404.6-128.7) = 275.9 MJ/d (68.2 %) (B)

- Condensate pipe diameter: 2½ inches - Length of pipe 2½: 50 meters - Surface temperature of pipe: 87 0C - Working time: 8 h/d For B, the difference temperature is 87-28 = 59 0C and nominal size of the pipe is

2½ inches, the heat loss is around 140 kcal/m.h.

Heat loss = 140 kcal/m.h. * 50 m * 8 h/d = 56,000 kcal/d (234.1 MJ/d) If the pipe is insulated, estimate surface temperature is 50 0C. As the difference temperature is 50-28 = 22 0C, the heat loss is around 55 kcal/m.h.

Heat loss = 55 kcal/m.h. * 50 m * 8 h/d = 22,000 kcal/d (91.9 MJ/d) Therefore, the energy can be saved (234.1-91.9) = 142.2 MJ/d (60.7%) Dyeing and Sizing section

- Condensate pipe diameter: 1½ inches - Length of pipe 1½: 90 meters - Surface temperature of pipe: 85 0C - Working time: 18 h/d As the difference temperature is 85-28 = 57 0C and nominal size of the pipe is 1½

inches, the heat loss is around 85 kcal/m.h.

Heat loss = 85 kcal/m.h. * 90 m * 18 h/d = 137,700 kcal/d (575.6 MJ/d) If the pipe is insulated, estimate surface temperature is 50 0C and the deference temperature is 50 – 28 = 22 0C, the heat loss is around 35 kcal/m.h. Heat loss = 35 kcal/m.h. * 90 m * 18 h/d = 56,700 kcal/d (237 MJ/d) Therefore, the energy can be saved (575.6-237) = 338.6 MJ/d (58.8%) Feed water tank

- Feed water tank diameter: 1.5 m. - Height of tank: 1.2 m. - Surface area: 7.41 m2 - Surface temperature of tank: 84 0C - Working time: 18 h/d

100

For feed water tank, the difference temperature is 84-28 = 56 0C and area of the tank is 7.41 m2, the heat loss per square meter is around 474 kcal/m2h when compare with the bare pipe diameter 24 inch from Fig.E-1

Heat loss = 474 kcal/m2h. * 7.41 m2* 18 h/d = 63,222 kcal/d (264.3 MJ/d) If the feed water tank is insulated, estimate surface temperature is 50 0C. As the difference temperature is 50 – 28 = 22 0C, the heat loss per square meter is around 210.5 kcal/m.h.

Heat loss = 210.5 kcal/m2h. * 7.41 m2* 18 h/d = 28,076.5 kcal/d (117.4 MJ/d) Therefore, the energy can be saved (264.3-117.4) = 146.9 MJ/d (55.6%) Condensate Storage Tank

- Surface area: 0.43 m2 - Surface temperature: 90 0C - Working time 18 h/d For condensate storage tank, the difference temperature is 90-28 = 620C and area of

the tank is 0.43 m2, the heat loss per square meter is around 631.6 kcal/m2h when compare with the bare pipe diameter 24 inch from Fig.E-1

Heat loss = 631.6 kcal/m2h. * 0.43 m2* 18 h/d = 4888.5 kcal/d (20.4 MJ/d) If the feed water tank is insulated, estimate surface temperature is 50 0C. As the difference temperature is 50 – 28 = 22 0C, the heat loss per square meter is around 210.5 kcal/ m2h.

Heat loss = 210.5 kcal/m2h. * 0.43 m2* 18 h/d = 1629.3 kcal/d (6.8 MJ/d) Therefore, the energy can be saved (20.4-6.8) = 13.6 MJ/d (66.6 %)

Total heat loss of the uninsulated pipe and feed water tank = 1582.6 MJ/d Total heat loss if the pipe and feed water tank are insulated = 601.9 MJ/d Therefore, Total energy can be saved (1582.6-601.9) = 980.7 MJ/d (62 %)

101

Figure E-1 Released Heat from Bare Pipe

102

Appendix F Economical Feasibility Analysis for Waste Minimization

103

Table F-1 Costing Details of Water Reused System

Items Details Cost (Baht)

Investment Costs Pump +Motor 1 HP

Pipes diameter 1.5 inh. Storage Tank

Labor Cost

(6 m/700 B)* 30 m

15,0003,500

30,000

20,000

Total 68,500

Depreciation Cost 68,500/10 (Life time 10 yr. Without salvage value) 6,850

Operating Cost 1 HP*0.7457 Kw *10 hr/d *300 d/yr. * 2.33 B/Kw 5,213

Maintenance Cost 5 % of installation cost 3,425

Water saving Cost 88 m3/d * 6.5 B/ m3 * 300 d/yr 171,600

Annual Saving Cost WC - MC- OP - DC 156,112

Payback Period

Total Investment Cost/Annual Saving Cost 0.44

Table F-2 Costing Details of High Pressure Cleaning System

Items Details Cost (Baht)

Investment Costs Spray Gun

6 Spray Guns * 750 Baht 4,500

Total 4,500

Depreciation Cost 4,500/5 (Life time 5 yr. Without salvage value) 900

Water saving Cost 8 m3/d * 6.5 B/ m3 * 300 d/yr 15,600

Annual Saving Cost WC - DC 14,700

Payback Period

Total Investment Cost/Annual Saving Cost 0.31

104

Table F-3 Costing Detial of Energy Conservation

Items Details Cost (Baht)

Investment Costs Glass wood insulator Glass wood insulator

Labor Cost

(650 B/m) * 260 m for pipes (1000 B/m2) * 7.84 m2 for tank

169,8007,840

30,000

Total 207,640

Depreciation Cost 207,640/15 (Life time 15 yr. Without salvage value) 13,843

Maintenance Cost 5 % of installation cost 8,882

Energy saving Cost (980.7 MJ/d)/(42.5 MJ/kg)/(0.86 kg/L) * 6.75 B/L * 300 days

54,334

Annual Saving Cost EC - DC - MC 31,609

Payback Period

Total Investment Cost/Annual Saving Cost 6.57