Life Cycle Assessment of Two Textile Products Wool and Cotton

INTEGRATED MASTER IN ENVIRONMENTAL ENGINEERING 2012/2013 LIFE CYCLE ASSESSMENT OF TWO TEXTILE PRODUCTS WOOL AND COTTON ALBINO ANDRÉ MOREIRA CARDOSO Dissertation submitted for the degree of MASTER ON ENVIRONMENTAL ENGINEERING President of the jury: Prof. Dr. Cidália Maria de Sousa Botelho (Assistant Professor from the Department of Chemical Engineering from the Faculty of Engineering, Porto University, Portugal) ___________________________________________________________ Supervisor at the University: Prof. Dr. Belmira de Almeida Ferreira Neto (Assistant Professor from the Department of Metallurgical and Materials Engineering from the Faculty of Engineering, Porto University, Portugal) Supervisor at the hosting institution: Dr. Mireille Faist Emmenegger (Director, operations, project manager of Quantis Switzerland/Germany. Formerly researcher at Empa) September 2013 Master Thesis LCA of Two Textile Products: Wool and Cotton i Abstract The textiles represent the fourth largest manufacturing industry worldwide in terms of revenues and production. This sector leads to significant burdens in the environment due to the activities taking place during the yarn fibre manufacture including the raw fibre production (agriculture), spinning, dyeing and finishing processes. Therefore, it is very important to assess the impacts and find ways to reduce its impacts and improve the environmental performance of this industrial sector. In the present study the life cycle stages associated with the processing wool and cotton are assessed based on real data obtained from some of the company (i.e. HUGO BOSS) suppliers’ activity in 2011. It comprises the production of raw fibre (sheep farming and cotton cultivation), spinning, dyeing, dyeing & bleaching and scouring wool. The analysis was performed with the SimaPro software using ILCD impact assessment method and results are presented for the characterization step. The method allowed the quantification of potential environmental impacts at midpoint and the selected impact categories were: climate change, ozone depletion, human toxicity cancer effects, human toxicity non-cancer effects, eutrophication (freshwater and marine), freshwater ecotoxicity and water resource depletion. The inventories were built using primary data made available by suppliers and secondary data was estimated based on existing models (mainly to model agriculture emissions) or taken from the ecoinvent databases. Results are analysed life cycle stage by life cycle stage for each material. Scenarios were created in order to assess the multiple combinations possible for the production of cotton and wool yarns based on the distinct processes taking part at each supplier. A worst and a best case scenarios are built that both materials can be compared in terms of impact. Results show that in general, the field emissions in raw fibre production (more specifically the livestock emissions in sheep farming and the losses in the fertilizers to the environment in the cotton cultivation) show to contribute largely to the overall environmental impact categories studied. The production of fertilizers is another activity that shows a relevant pressure in the environment. The results concerning the spinning processes show that the large electricity demand and electricity production leads to the major contribution in the cotton and the wool yarns manufacture. Water use, packaging and chemicals production (mainly in wool’s spinning mills) also contribute significantly to environment problems. The dyeing (and bleaching) and scouring wool as a wet processes need considerable amounts of water and that is very much associated with the energy needed for heating and cooling baths and for drying yarns or fibres. Activities which are not directly associated to the company activity as the production of wire used for packaging and transoceanic transports emerge as important contributors in most of the categories for the scouring mill. Master Thesis LCA of Two Textile Products: Wool and Cotton ii When the entire supply chain is analysed it is observed that the raw fibre production (named as sheep farming for wool and cotton cultivation for cotton) is the life cycle stage that is the main contributor to the impacts. In the worst case scenario, wool yarns have the largest impacts in the overall results except for freshwater eutrophication and water resource depletion. When a best case scenario is regarded, cotton has the largest burdens in categories as freshwater eutrophication, marine eutrophication, freshwater ecotoxicity and water resource depletion. Keywords: Life Cycle Assessment (LCA) | Textiles | Cotton | Wool | Sheep farming | Cotton cultivation | Scouring wool | Spinning | Dyeing | Bleaching Master Thesis LCA of Two Textile Products: Wool and Cotton iii Acknowledgments I would like to express my gratitude to my supervisor at FEUP, Belmira Neto, for the useful comments, remarks and engagement throughout the process of this master thesis; for the excellent opportunity which she created for the students to learn more about LCA in Academia SimaPro - group which made my motivation in this field grow up. Furthermore I would like to thank my supervisor at EMPA, Mireille Faist, for the fantastic opportunity offered to do my internship with her, for introducing me to the topic, for the support on the way and great reception in Switzerland. I would like to thank my team in HUGO BOSS for its assistance, guidance and for letting me to use this data for my master thesis: Daniele Massetti, Heinz Zeller, Michela Gioacchini and Paola Mugavero. I'm very grateful for the opportunity I have to work with you and, consequently, to continue my studies on this field. I’m very grateful to all the people I met in EMPA and ecoinvent for your support, good discussions, great chocolates, coffee breaks and, of course, for the kendama training! For all of these I wish to thanks Andrea Del Dulce, Ibrahim Ismail, Simon Gmuender, Rainer Zah, Juergen Reinhard, Tereza Lévová, Linda Wegelin, Emilia Moreno Ruiz, Gregor Wernet, Dominic Notter and Hans-Jörg Althaus. I am indebted to my many friends who supported me at several levels during the last years. I wish to thank you very much: - Catarina Carneiro for the unforgettable support and care; - João Carvalho who I completely admire its friendship, knowledge (and guitar skills) - thank you for your fellowship and help throughout these years at FEUP; - Isabel Ramos, Bruno Martins, Filipe Marques, Frederico Leite, João Carvalho and Paulo Carvalho for all the good times we had and support you offer; - Sr. Abel and Dona Palmira whose friendship was more than that; - Nuno Rocha for the important help and guidance during my first years at FEUP. For the time we have been studying, working and sharing knowledge I want to thanks: Ana Cardoso, Ana Cavadas, Eduardo Ventura, Emanuel Costa, Franklim Cardozo, Nuno Silva, Manuel Macedo, Maria Oliveira and all the other colleagues I had the pleasure to work with during the last 5 years. I would like to thank Eleni, Nara, Ibrahim, Jamile, Ana, Georgi, Sohini and Joeri for the fantastic fellowship and for the cultural experiences shared in Switzerland. Last but certainly the most important, I would like to thank my parents, sisters, nieces and my brothers-in-law for their endless love and entire support. I will be grateful forever for your love, help and teachings. Master Thesis LCA of Two Textile Products: Wool and Cotton iv Master Thesis LCA of Two Textile Products: Wool and Cotton v Contents Abstract ......................................................................................................................................................................... i Acknowledgments .................................................................................................................................................. iii Contents ...................................................................................................................................................................... v List of Figures ............................................................................................................................................................ ix List of Tables ............................................................................................................................................................. xi Lists of abbreviations ........................................................................................................................................... xiii 1 INTRODUCTION .............................................................................................................................................. 1 1.1 EcoLogText ............................................................................................................................................... 2 1.2 Thesis objective and goal ................................................................................................................... 3 1.3 Thesis outline .......................................................................................................................................... 4 2 CHARACTERIZATION OF THE LIFE CYCLE STAGES ............................................................................. 5 2.1 Wool life cycle stages: sheep farming and scouring wool ..................................................... 6 2.2 Cotton life cycle stages: cultivation and ginning ....................................................................... 7 2.3 Mechanical and chemical processes for dyed yarn production (for wool and cotton) 8 2.4 Environmental aspects from the production of textiles .......................................................... 9 2.4.1 Water consumption .................................................................................................................. 11 2.4.2 Energy consumption ................................................................................................................ 12 2.4.3 Air Emissions................................................................................................................................ 12 2.4.4 Soil emissions .............................................................................................................................. 13 2.4.5 Solid waste production ............................................................................................................ 13 2.3 Overview of LCA studies for textile products: cotton and wool ....................................... 14 3 THE LIFE CYCLE ASSESSMENT METHODOLOGY .............................................................................. 17 3.1 LCA methodological phases ........................................................................................................... 17 3.2 Goal and Scope of the study .......................................................................................................... 19 3.2.1 System boundaries .................................................................................................................... 20 3.2.2 Allocation process ..................................................................................................................... 23 3.3 Inventory analysis ............................................................................................................................... 23 3.3.1 Inventory for sheep farming .................................................................................................. 24 3.3.2 Inventory for cotton cultivation ........................................................................................... 28 Master Thesis LCA of Two Textile Products: Wool and Cotton vi 3.3.3 Inventory of mechanical and chemical processes for dyed yarn production ..... 32 3.3.4 Datasets from ecoinvent ......................................................................................................... 36 3.4 Impact assessment ............................................................................................................................. 36 4 RESULTS AND DISCUSSION ..................................................................................................................... 39 4.1 LCA of Wool Yarns .............................................................................................................................. 39 4.1.1 Sheep farming............................................................................................................................. 39 4.1.2 Scouring wool ............................................................................................................................. 43 4.1.3 Spinning ........................................................................................................................................ 46 4.1.4 Dyeing ............................................................................................................................................ 51 4.2 LCA of Cotton Yarns .......................................................................................................................... 54 4.2.1 Cotton cultivation ...................................................................................................................... 54 4.2.2 Spinning ........................................................................................................................................ 57 4.2.3 Dyeing and bleaching .............................................................................................................. 60 5 ANALYSING SCENARIOS FOR YARN PRODUCTION (COTTON AND WOOL) ....................... 63 5.1 Identifying and assessing all scenarios ....................................................................................... 63 5.1.1 Wool yarns ................................................................................................................................... 64 5.1.2 Cotton yarns ................................................................................................................................ 66 5.2 Analysing the best and worst results from scenarios ........................................................... 67 5.2.1 Wool yarns ................................................................................................................................... 68 5.2.2 Cotton yarns ................................................................................................................................ 70 5.3 Comparative analysis of cotton and wool ................................................................................. 72 6 CONCLUSIONS.............................................................................................................................................. 75 7 RECOMMENDATIONS FOR FUTURE WORKS .................................................................................... 79 Bibliographic references ..................................................................................................................................... 81 Appendixes .............................................................................................................................................................. 85 Appendix A: ecoinvent datasets used for energy ..................................................................................... 87 ELECTRICITY ................................................................................................................................................... 87 HEAT ................................................................................................................................................................. 87 Appendix B: ecoinvent datasets used for agriculture (sheep farming and cotton cultivation) 89 MACHINERY ................................................................................................................................................... 89 FEEDSTUFF ...................................................................................................................................................... 89 FERTILIZERS .................................................................................................................................................... 89 Master Thesis LCA of Two Textile Products: Wool and Cotton vii PESTICIDES ..................................................................................................................................................... 90 CHEMICAL TREATMENTS OF SHEEP AND COTTON SEEDS ......................................................... 90 EMISSIONS ..................................................................................................................................................... 91 Appendix C: ecoinvent datasets used for packaging materials ........................................................... 93 Appendix D: ecoinvent datasets used for water, wastewater treatment and water emissions 95 WATER CONSUMPTION ............................................................................................................................ 95 WASTEWATER TREATMENT PLANT ...................................................................................................... 95 WATER EMISSIONS ..................................................................................................................................... 96 Appendix E: ecoinvent datasets used for chemicals, dyestuffs and auxiliaries .............................. 97 Appendix F: ecoinvent datasets used for transports ............................................................................... 99 Appendix G: ecoinvent datasets used for solid waste........................................................................... 101 Appendix H: Heavy metal content in fertilizers, wool and cotton .................................................... 103 HEAVY METALS IN WOOL ...................................................................................................................... 103 HEAVY METALS IN FERTILIZERS ........................................................................................................... 104 HEAVY METALS UPTAKE IN COTTON ................................................................................................ 105 Appendix I: Selection of the best supplier for sheep farming............................................................ 106 Master Thesis LCA of Two Textile Products: Wool and Cotton xiv Master Thesis LCA of Two Textile Products: Wool and Cotton 1 1 INTRODUCTION The textiles represent the fourth largest manufacturing industry worldwide in terms of revenues and production. The apparel sector is forming the most representative sector of this industry [1]. The textile industries are responsible for the production of yarn, fabric, and finished goods from natural or manmade fibers. Table 1 shows the different materials possible to produce from natural and man-made fibers. Table 1 – Textile fibres [2] Categories Sub-Categories Example of fibres Natural Fibers Organic Vegetable fibers Cotton Flax, Hemp Jute, Sisal, Broom Animal fibers Wools Silk Inorganic Mineral fibers Basalt Asbestos Manmade fibers Organic regenerated natural fibers Regenerated cellulose Viscose Cellulose acetate Cellulose triacetate Organic synthetic polymers Polyester Polyamide Polyolefins Polyacrilic Inorganic fibers Glass Carbon The fiber production and consumption are increasing annually due to the population growth, the increasing fiber consumption with increasing per capita prosperity and the continual increasing of new applications for textiles The clothing and textiles constitute about seven per cent of the world’s exports in terms of sales. About one third of the sales were made in Western Europe, the same amount in North America and one quarter in Asia. In 2000 the industry employed 26.5 million people worldwide. More than 25 per cent of the world’s production of clothing and textiles is made in China [3]. The volume of the world’s fiber production, associated to the textile industry in 2012, was around 88.5 Mt, from which 56 Mt were manmade (40% polyester) and 32.5 Mt natural fibers (80% cotton) [4]. Summing up synthetic fibers does represent 64% of the overall amount of the production of textile fibers. Cotton and wool are the world‘s most produced natural fibers. FAO in 2011 estimated a production of 26.1 Mt for cotton and 2.0 Mt for wool. China, United States and India are the three world level largest producers of cotton with productivity yields amounting respectively 6.58, 5.98 and 3.41 Mt. In the same year, the annual wool production is around 2.0 Mt. China has a share of 0.39 Mt, Australia 0.36 Mt and New Zealand 0.17 Mt [5, 6]. Master Thesis LCA of Two Textile Products: Wool and Cotton 2 The World Bank estimates that 17 to 20 per cent of industrial water pollution comes from textile industry, mainly from the operations of dyeing and finishing. This sector is the second main contributor to clean water pollution. This is associated with the large amounts of water used, the energy needed to heat water and the large quantities of chemicals used in these processes[7]. The consumer’s consciousness for textile products produced in more environmentally friendly way is increasing every time. At the same time its price is also an important criterion for purchasing. The pressure in this industry is promoted by markets which demand products with superior performance and quality as well as by regulations for sustainability and cleaner production. This is a strong motive for the textile companies to focus more and more on the production of sustainable products regarding its supply chain. It is now clear that optimizations in the management performance of the supply chains turns it possible to achieve higher profits and improve the social and environmental performance of the business sector [8]. To improve this in a company or industry, it is necessary to understand how the supply chain system works, which symbiosis exists and where the opportunities to improve those relationships are. In an environmental point of view, life cycle assessment is an important tool used to evaluate the environmental burdens over the entire life-cycle of products and services. This tool analyses all the life cycle stages of products from raw material extraction to production process, distribution, use, and final disposal. It offers a holistic perspective of the supply chain performance and can help decision makers on identifying more efficient supply chains. 1.1 EcoLogText The work presented is part of my internship tasks in the EcoLogTex project, at the Life Cycle Assessment and Modelling Group of EMPA (the Swiss Federal Laboratories for Materials Science and Technology) in collaboration with HUGO BOSS and IDSIA (Istituto Dalle Molle di Studi sull'Intelligenza Artificiale). Currently, due to a spin-off to the new branch of Quantis (Quantis Switzerland / Germany), the EMPA’s group doesn’t exist anymore and the project is now developed by the latter mentioned organization (Quantis). The project EcoLogTex aims to deliver a new methodology and a tool (web-based software application) to evaluate alternatives for the textile supply chains taking into account the impact on the environment, while satisfying corporate social responsibility constraints. The results of this project will allow the textile companies to efficiently optimize their supply chains and suppliers to benchmark themselves. The integration of LCA in each step of the supply chain for the textile industry might add the environmental perspective when designing a more environmentally effective supply chain [9]. Questionnaires specific for the different life cycle stages of the supply chain for the two textile products in focus (cotton and wool) have been developed and sent to HUGO BOSS’ suppliers and to other companies active in its supply chains (cotton growers, spinning mills, dyeing mills, finishing companies, Master Thesis LCA of Two Textile Products: Wool and Cotton 3 assembly etc.), in order to obtain data used to assess the different processes from the life cycle of textile production. The information is made available from the suppliers or estimated. The data considered includes specific data from companies as the consumption of energy, chemicals and water and production of waste as well as emissions in water and air and soil. The values were modelled into an inventory using the Ecoinvent database v2.2 for background data (www.ecoinvent.org). During the internship at EMPA the data was analyzed and was used to model the environmental impacts by using SimaPro (LCA commercial software tool). The results obtained for the different suppliers from different parts of the supply chain for the two main fabrics in focus by EcoLogTex (i.e. cotton and wool) are presented in this study. Moreover, scenarios for the production of dyed wool and cotton are created, the worst and best case selected and the yarn production for both cases scenarios and materials are compared. 1.2 Thesis objective and goal The main goal of this study is to assess the environmental burdens associated with the different life cycle stages from two textile products (cotton and wool) comprising: fibre production, spinning, dyeing, dyeing & bleaching and scouring wool. Scenarios for the production of the two yarns for each material (cotton and wool) were built based on the distinct processes reported by the suppliers for the different life cycle stages. This study compares the worst and the best scenarios in terms of environmental impacts for each material. Inventory data is collected from several suppliers and refer to 2011. This study is elaborated following the scope of EcoLogTex project and its specifications. The environmental impacts are quantified using LCA and the guidelines reported in the ISO 14040:2002 [10]. In terms of the assessment of the impact categories this work performs LCIA until the characterization step and the methods used are taken from ILCD recommendations [11] due to the requirements of the above mentioned project. The main life cycle stages contributing to the impacts are identified. This is to say that the relevant emissions underlining each calculated impact categories (e.g. climate change induced by energy use due to greenhouse gas emissions from power plants). In the end scenarios are created in order to ascertain a comparison for the environmental performance of wool and cotton dyed yarns production. A comparative analysis among the best and the worst scenario is made. Master Thesis LCA of Two Textile Products: Wool and Cotton 4 1.3 Thesis outline Chapter 1 overviews the main characteristics of the textile industry, including the annual average production and its environmental pressures. The role of the study in the EcoLogTex project is summarized and, at the end, the thesis’s goals, objectives and structure are identified. Chapter 2 presents and characterises the main processes of the textile industry supply chain for wool and cotton. A review of the main LCA studies in this sector and the main conclusions in terms of environmental problems are briefly presented. Chapter 3 presents the LCA methodology and its application to the study. Following the ISO 14040:2002 [10] the main steps of LCA (goal and scope, inventory analysis, impact assessment and interpretation) are described while study data is presented. The study boundaries for each life cycle stage are drawn and the inventory data analysed. Chapter 4 presents and discusses the LCA results for each life cycle stage of each material assessed (cotton and wool). The major contributors are identified and discussed. In Chapter 5 combinations of several possible processes are presented resulting in the production of cotton and wool yarns. Subsequently two cases scenarios (worst and best) are identified and used to perform a comparative evaluation for each life cycle stage and for each textile product analysed. This is to understand which life cycle stages contribute mostly to the overall impact and to compare the environmental performance of the two textile products. Chapter 6 draws and discusses the conclusions of the study. Recommendations for further works, based on the identified limitations, are listed. Master Thesis LCA of Two Textile Products: Wool and Cotton 5 2 CHARACTERIZATION OF THE LIFE CYCLE STAGES Generally, all textile fibers are processed in a similar way: raw fibers are produced, collected and prepared to be spun by spinning mills. The produced yarn might pass through other pretreatments before being transformed into a knitted or woven fabric. After that, fabrics are cut and assembled into clothes which are ready to be transported to retailers, distributed to stores and sold to the final consumer, which will use them until its final destination. Between different stages the use of transportation is needed and the travelling distances might vary from short to medium and long (e.g. country, continent or transcontinental trips). This industry is identified has having one of the most complex industrial chains [12]. The present study focus on the production of wool and cotton dyed yarns. Having distinct natural origins (vegetal and animal), some processes are different for the two materials (cotton and wool). The cotton is harvested, dried and ginned while the greasy wool is scoured after the sheep shearing. Figure 2 and Figure 1 illustrate, respectively for cotton and wool, an example of the supply chain highlighting the main activities taking place on the production process (i.e. fibre to textile fabric). Figure 1 - Main life cycle stages of the supply chain for wool. The assembly, use phase and the final disposal is here disregarded. Transports link the presented stages Master Thesis LCA of Two Textile Products: Wool and Cotton 6 Figure 2Main life cycle stages of the supply chain for cotton. The assembly, use phase and the final disposal is here disregarded. Transports link the presented stages In the present section specifications for the life cycle stages of cotton and wool textiles are identified and described, its generic stages of mechanical and chemical processing for dyed yarns production are characterized and the main environmental concerns are summarized in the following. The present study only comprises the life cycle stages which data was supplied during the internship. It includes the stages of sheep farming, scouring wool, cotton cultivation, ginning spinning (wool and cotton), dyeing (wool) and dyeing & bleaching (cotton). However, other finishing processes might occur throughout the supply chain of each material as presented in 2.3. These were, however, disregarded from this thesis scope. 2.1 Wool life cycle stages: sheep farming and scouring wool Wools might be produced from sheep, goat, alpaca, camel and rabbit among other animals. Wool’s production is mainly from sheep. In this case, the supply chain starts in grazing and shearing the ovine followed by the removal of impurities of the fleece. After this, wool is ready to be spun and dyed. Sheep farming: the sheep is grazed on pasture and different cares are needed. Farmers have to ensure the correct nutritional requirements of animals (around 4L of water and 1kg of dry Master Thesis LCA of Two Textile Products: Wool and Cotton 7 matter of food per day) as well as to prevent diseases (chemical or biological treatments). Sometime agricultural activities as fertilizers application or irrigation are developed on pastures in order to increase the meadow yield. The feedstuff as silage or grain may be imported or locally produced when the available grass is not enough. In fact, on average, one sheep produces about 4 to 5 kilograms of wool and around 40 to 60 kilogram of meat per year [13-15]. This animal has also an important role on greenhouse gases emissions due to its metabolic activity – enteric fermentation and manure left on pasture. In order to collect the fleece from the sheep there is the activity of shearing. It is usually made once a year in the springtime [14-16]. Most of the farmers worldwide shear sheep by hand and an experienced shearer can shear up to 200 sheep per day [17]. The fleece is kept in one piece and due to its content of natural grease it is named as greasy wool. Scouring wool: it is a process similar to the scouring presented below (section 2.3) but in the case of wool it is always performed after shearing the sheep to remove impurities from the fleece. The main impurity is grease and suint and the goal of the process is to remove it using detergents. The extracted grease is turned into lanolin (byproduct with commercial value) [18]. Scouring facilities generates strongly alkaline effluents and significant loads of BOD5 and COD [2]. Usually the scouring mills include processes of carding and combing and, in that case, the final product is named as wool top. This product is in a form ready for spinning. Wool tops are recombed in spinning mills in order to adjust the slivers weight and thickness as well as to realign fibers after dyeing and blending processes [19]. 2.2 Cotton life cycle stages: cultivation and ginning The life cycle stage of cotton textiles begins in the cultivation and it is followed by ginning. The fresh ginned cotton is ready to be spun or dyed in processes which are similar for both materials (cotton and wool). Cultivation – cotton (Gossypium species) is a perennial shrub often cultivated as an annual crop for cotton-producing industries. Its propagation is usually made by seeds which are pre-treated with fungicides, insecticides and plant growth regulators to provide protection against diseases and pests (this pesticides are also applied to the crop during growing periods); plants can reach 1 to 2 meters high (sometimes more) [20] and the productivity rate equals a maximum annual average production ranging from 1 to 2 tonnes of seed cotton per hectare [21]. At this stage the raw fiber is named as seed cotton due to the presence of seeds mixed with lint (cotton fibers). Once the seed cotton is picked it is compacted into modules and is then transported to a cotton gin. Ginning – this process is usually performed by cotton growers and it follows the harvest. The cotton seeds are stored in a natural capsule of the plant, surrounded by lint (makes up approximately 35% of the seed cotton) [22]. Ginning is a mechanical process used to separate the fibers (the more commercially interesting part of the plant) from the seeds. In order to reduce the moisture and improve the fiber quality, ginning is accompanied by Master Thesis LCA of Two Textile Products: Wool and Cotton 8 drying processes that can be made by natural or artificial techniques [22]; these fibers are then compressed and baled. At this stage, the final product might be called as cotton lint or ginned cotton. 2.3 Mechanical and chemical processes for dyed yarn production (for wool and cotton) Ginned cotton and scoured wool will follow the same life cycle stages. They will be spun and dyed in order to create a dyed yarn. Spinning: is the process of transforming fibers into yarn; most of the mills encompasses processes as mixing (blending), cleaning, carding, combing, drawing and spinning fibers, followed by coning and packaging yarns.  Carding is the process which separates the fibres and then assembles it into a loose strand, there is no preferential orientation of the fibres and a web-like fibre is formed using a carding machine consisting of rollers or drums which have pointed wires protruding from the surface. The wires pull the cotton fibre into line forming a sliver or a type of rope [22].  Combing is the process that organizes fibres in a parallel orientation and removes some organic matter as straw or leafs remaining on the fibres. This activity is performed after carding and it offers a high quality of threads when compared with carded materials.  The slivers are thinned out or thinned by using a process called drawing and drafting. This is completed by a series of rollers which make the fibres a consistent size in preparation for spinning [22].  Spinning the yarn might be spun directly from the slivers (rotor spinning) or the fibre is twisted into thinner roving before being spun (ring spinning) [22]. Finishing: The “wet processes” also known as “finishing processes” (as presented in Figure 3) are the main activities of fabric preparation which might take place in different stages of the material production (fiber, yarn or fabric) depending on the required specifications of the final product. Examples of these activities are dyeing, bleaching, mercerizing, printing, desizing and washing [2, 12]. Every stage of production might include its finishing processes which allows the best fiber, yarn or fabric quality; in textile industry it is often applied after weaving or knitting the fabric in order to reach desirable fabric properties in terms of handle (softness and flexibility) and drape; the key goals are to remove surface hairs, increase fiber binding / cohesion and increase fiber friction according to the final product specifications [1]; finishing processes might comprise different processes according to the final desired product. Some examples of finishing or pretreatment processes are:  Dyeing: process of adding color to fibers; batch, continuous or semi-continuous processes might be used depending on different factors as the stage of the material (fiber, yarn, fabric or garment), size of dye lots and quality requirements in the dyed Master Thesis LCA of Two Textile Products: Wool and Cotton 9 fabric; the machinery must be resistant to attack by acids, bases, other auxiliary chemicals and dyes [23].  Printing: Is the application of color to the surface of a fabric in a predetermined pattern using paste or ink; it may be considered as localized dyeing [1].  Bleaching: is the process to make these products brighter or whiter; the most common bleaching reagent is hydrogen peroxide and may also be used reagents like sodium hypochlorite, sodium chlorite/chlorate and sulfur dioxide gas [2]; sometimes bleaching can be carried out in combination with other treatments: bleaching / scouring, bleaching / dyeing bleaching / scouring / desizing [12]. When the material has to be dyed in dark colors it can be directly dyed without requiring bleaching. On the contrary, bleaching is an obligatory step when the fiber has to be dyed in pastel colors or when it will need to be subsequently printed. In some cases, even with dark colors a pre-bleaching step may be needed [12].  Mercerizing – consists of the pre-treatment of cotton fibers with caustic soda or liquid ammonia in order to improve tensile strength, dimensional stability and lustre [12]; this treatment increases the dye affinity of the materials, reducing the dyestuff consumption in the further process of dyeing; it can be done in two basis stages of material: yarn or fabric [2, 12]; usually post bleaching and pre-coloring process [24].  Scouring: commonly scouring is the process that aims the removal of impurities as pectins, proteins, fat and waxes from raw fibers; the fibers go through a series of bowls and the scums are removed [12].  Desizing: Sizing agents are introduced by the weaving firm in order to strength the fabric, but its excesses has to be removed by desizing processes using enzymes and other auxiliaries; as a result it has a high waste water production.[12]. After the yarn production (including its finishing processes) the fabric is created by knitting or weaving – at this stage we may also have a garment product (e.g. knitted wear).Knitting is the process responsible for the production of knitted fabrics. The material is produced by set of connected loops from series of yarns while weaving, similarly to knitting, originates woven fabrics by interlacing two types of threads [25]. After knitting or weaving, might be the life cycle stage of assembly in which the fabric is cut in a determined shape and assembled into a garment, usually using sewing processes. Sometimes trimmings are applied to the final clothing – it is the final stage of textile making. 2.4 Environmental aspects from the production of textiles Environmental impacts occur at every stage of the life cycle of a product. More specifically and due to the growing need to lower the environmental impacts associated with the production of clothes. New patterns of production must be employed in such a way that the use of non-renewable resources, water, chemicals, fertilizers and land would be minimized throughout the supply chain. In summary, the textile fashion companies are focusing more and more on the production of sustainable products. Master Thesis LCA of Two Textile Products: Wool and Cotton 16 Table 7 - Set of selected studies regarding LCA and LCIA of cotton and wool. Study Environmental Improvement Potential of Textiles – IMPROtextiles Life Cycle Assessment of Cotton Fiber & Fabric LCA of cotton towels A spatially explicit life cycle inventory of the global textile chain Global warming contributions from wheat, sheep meat and wool production Merino Wool Total Energy Use and Carbon Dioxide Emissions Reference Beton et al. (2006)[27] Cotton Incorporated and PE International (2012)[36] Blackburn and Payne (2004)[37] Steinberger et al.(2009)[38] Biswas, Graham, Kelly and John (2010)[13] Andrew Barber and Glenys Pellow (2006)[18] Location EU-27 Cotton growers: U.S., China and India; fabric production: Turkey, India, China, and Latin America; U.S. - Australia New Zealand Goals Comparison of different fibre types (Viscose, Flax, Silk, Wool, Cotton, Polyester, PA6, Acrylic and Polypropylene) Compile a robust and current LCI dataset for global cotton fiber production and textile manufacturing. Ascertain the impact of domestic laundering on the life cycle of cotton articles and whether techniques to provide an overall greener life cycle. Establishing a country level, spatially explicit life cycle inventory (LCI) Comparison of the life cycle global warming potential of wheat, meat and wool in different pasture systems Develop LCI for New Zealand merino farms, offering benchmark figures to this industry based on a LCA perspective. FU 1 kg of finished woven fabric (tshirt) 1000 kg of cotton fiber, 1000 kg of knit fabric, and 1000 kg of woven fabric dyed 600g of a 100% cotton towel 1 t-shirt (110g) 1 kg of wheat, sheep meat and wool produced Tonne of dry wool top; tonne of greasy wool Life cycle stages Raw material production, cleaning, desizing, spinning, printing and dyeing, weaving and finishing Cotton production, ginning and knit and woven fabric manufacturing (spinning, dyeing, knitting/weaving and finishing). Growing cotton fibre; towel making (ginning, spinning, weaving, dyeing and finishing and assembly); consumer use and disposal. Agriculture, Production (spinning, knitting, dyeing, apparel, transport); Use (washing, drying and disposal) Agricultural machinery; fertilizer and pesticide (use, production and transportation) and emissions from pastures and crop fields. Production and use of fertilizers and pesticides; wool processing (farming, shearing, scouring, combing) and shipping wool top to China. Method ReCiPe USEtox™ - - - - Impact categories Midponts: climate change, human toxicity and freshwater ecotoxicity. Endpoints: human health, ecosystem diversity and resource availability. Acidification, eutrophication, global warming, ozone depletion, smog creation, energy demand, water use and water consumption Energy consumption The carbon dioxide and sulphur dioxide emissions from energy consumption in each life cycle stage Global warming potential - Hot spots Finishing and raw material production are the biggest contributors. Finishing assumes an important role in cotton fabric's LCA while raw material production is the main cause in wool product's impacts. Agriculture: field emissions and fertilizer use; Knitted fabric: mainly spinning, secondly dyeing and finishing; Woven fabric: mainly spinning, secondly finishing, dyeing and weaving. 76% use phase 19% towel making 4% growing cotton CO2 emissions: Agriculture (15%); Spinning (7%); Dyeing (7%); Use phase (65%). SO2 emissions: Agriculture (30%); Spinning (17); Dyeing (13%); Use phase (25%). CH4 emissions from enteric methane production and from the decomposition of manure accounted for a significant portion of the total emissions. On-farm activities have a contribution of 67% while processing 30% on the overall results. Conclusions Raw material production and finishing are the main contributors in the overall results. Cotton as the highest impacts in all the assessed categories when compared with wool. Energy and water use are the significant causes to the overall results. Agriculture has a contribution up to 20% in the final results while in water consumption its contributions are around 80%. Within towel making processes, dyeing and spinning are the high input processes. In this LCI study the production stages of spinning and dying are also the largest contributors for these emissions in which both are responsible for about 50% of the total scores The life cycle GHG emissions of 1 kg of wool is significantly higher than that of wheat and sheep meat. Wool processing accounts for 47% of total energy use, of which almost 90% occurs during wool scouring. Limitations Based on high amount of literature data. Cotton is better modelled than the other fibres due to the amount of data available. Data not collected directly in the suppliers facilities. Focus on use phase LCI and only for emissions from energy consumption Specific for the local, only global warming assessed and downstream processes missing. This study only evaluates one impact category (energy use). Processing energy use was based on a German wool scouring and top making plant Master Thesis LCA of Two Textile Products: Wool and Cotton 17 3 THE LIFE CYCLE ASSESSMENT METHODOLOGY In the present study LCA is performed according to the principles of the International Organization for Standardization (ISO) both 14040 and 14044 series of standards for Life Cycle Assessment [10, 39]. Another methodological guideline for this study was The Hitch Hiker’s Guide to LCA [40]. The measurement of the potential environmental impacts is performed using the commercial software SimaPro (version 7.3.3, 2011). 3.1 LCA methodological phases Life Cycle Assessment is an environmental tool that allows to assess the environmental impacts of the product, process or activity (including the entire life cycle), encompassing stages as: extraction and processing of raw materials, manufacturing, transport, distribution, use and final disposal – accounting for water, air and soil emissions, energy and material consumption and waste disposal. LCA usually analysis a diversity of environmental impacts such as climate change, human toxicity, resources depletion, land use among others. According to the ISO standards, a LCA is carried out in four distinct phases: Goal and Scope Definition, Inventory Analysis, Impact Assessment and Interpretation (as shown in Figure 4). The Goal and Scope Definition is the first phase of LCA, which states the context of the study and the purposes of its results. Technical aspects and the level of detail considered are here defined by aspects as functional unit (FU) 1 , system boundaries, assumption and limitations, allocation methods and impact categories chosen. ISO standards require that the goal and scope of an LCA has to be clearly defined and consistent. Figure 4 - Phases of a LCA study [10]. 1 The FU defines exactly the object being studied, providing a reference to which the inputs and outputs can be related. It makes all the inputs and outputs of the studied product comparable. Master Thesis LCA of Two Textile Products: Wool and Cotton 18 The Inventory Analysis takes place after defining the goal and scope of the study, a fundamental component of LCA is the creation of the LCI, a complete list compiling the relevant inputs (energy and materials) and outputs (environmental releases or emissions) related to the functional unit defined. The Impact Assessment (LCIA) is when the quantified LCI flows are linked to its potential environmental impacts using a selected method. The method comprises selected categories of environmental impacts and characterization, normalization or weighting factors. This step is done using a systematic procedure based on a sequence of steps stated by the ISO standards (some of these steps are compulsory whilst others are optional):  Classification (compulsory): respecting the selected method, the inventory flows are classified according to the type of environmental impact they cause (e.g. CH4 emission are associated with climate change).  Characterization (compulsory): after classified, the substance flow must be characterized; each means that all the flows causing the same environmental impact are converted to the same representative unit (e.g. conversion of CH4 to CO2-eq).  Normalization (optional): this step offers a reference situation (country, region or world) of pressure on environment for each environmental impact category analysed [41].  Grouping (optional): consists of sorting and possibly ranking the impact categories.  Weighting (optional): is a subjective result where the impact categories are weighted relative to each other so that it can be possible to generate a single final score. The Interpretation is made throughout all the phases with the purpose to summarize and discuss the results achieved systematically and to verify if the results are in accordance with the defined goal and scope. Changes and recommendations are proposed and the final conclusions of the study are drawn. Master Thesis LCA of Two Textile Products: Wool and Cotton 19 3.2 Goal and Scope of the study The main goal of this study is to assess the environmental burdens associated to different life cycle stages of dyed yarns (cotton and wool) comprising: fibre production, spinning, dyeing, dyeing & bleaching and scouring wool; while ascertain about the environmental performance of wool and cotton dyed yarn production concerning the possible scenarios for its manufacture and the suppliers assessed for each material. The inventory data collected from several producers is from 2011. The different producers located worldwide may have distinct technologies within the same life cycle stage. The wool and cotton processes studied as its production yields are summarized in Table 8 for each company that supplied the inventory data. This table also identifies the functional unit (FU) utilized to report the data collected according to the final product of each life cycle stages. All the case studies are named with a code as listed in the table: as an example, three case studies supplying the greasy wool from sheep faming were used in the analysis and they are designated as F1, F2 and F3 (the same procedure was used in spinning, dyeing and dyeing & bleaching); cotton growers are distinguished by its mode of cultivation (conventional and organic) and; as only one scouring mill is assessed no code was defined. Table 8 – Data provided from suppliers for wool and cotton productions for 2011. Life cycle stage Case studies Location Annual average production, t Functional Unit (FU) WOOL Sheep farming F1 New Zealand 70 1 kg of greasy wool F2 Australia 50 F3 Australia 30 Scouring wool Italy 6000 1 kg of wool top Spinning S3 China 400 1 kg of wool yarn S41) Italy 4000 S5 Italy 1200 S6 Italy 250 Dyeing D11) Italy 4000 1 kg of dyed wool D2 Italy 650 D3 China 5500 COTTON Cotton cultivation Conventional Tajikistan 2.2 t/ha 1 kg of ginned cotton Organic Tajikistan 2.5 t/ha Spinning S1 China 12500 1 kg of cotton yarn S2 Switzerland 3500 Dyeing & Bleaching D&B 2 Italy 100 1 kg of dyed and bleached cotton D&B 3 China 30 1) S4 and D1 are developed under the same facility roof. It explains the equal amount of product produced. Master Thesis LCA of Two Textile Products: Wool and Cotton 20 3.2.1 System boundaries The LCA perspective adopted is cradle-to-gate for the case studies considered. The boundaries of the processes encompass the production of chemicals and auxiliaries needed for the supplier activities including raw materials, manufacture of intermediate materials and manufacture of the product being studied. Two main groups are identified for the two products, namely activities from the agricultural sector (cotton cultivation and sheep farming) and mechanical and chemical processes comprehending the scouring wool, spinning, dyeing and dyeing & bleaching. For all systems it was excluded the transportation and storage of materials as chemicals, auxiliaries, fertilizers, pesticides, feedstuff and packaging as well as activities that were not directly related to the production system as such the administrative, labs and other services operations. Figure 5 identifies the stages considered in the analysis by detailing the processes, input and output products concerned for the production of ginned cotton and greasy wool. Similarly, the Figure 6 illustrates the activities regarded to model the textile products (wool and cotton). Sheep farming and Cotton cultivation Regarding the main activities of these life cycle stages inputs and outputs from on-farm and pre-farm origin are included. In Figure 5 are illustrated the stages considered within the system boundaries. The modelling of these agricultural systems comprises:  The production of cotton seeds, fertilizers (organic or inorganic), pesticides (insecticides, fungicides and plant growth regulators), chemicals for seed 2 and sheep 3 treatments and sheep feed;  Machinery use in field works based on its consumption (e.g. harrowing, sowing and pesticides application);  Water consumed by the plants (cotton and pastures) and sheep;  Energy production from grid or own;  Emissions to air (NH3, N2O and NOx), water (NO3and PO43-) and soil (heavy metals and pesticides);  Emission from livestock (CH4, NH3 and N2O);  The process of ginning after harvesting cotton. 2 It refers to the application of fungicide, insecticide or a combination of both in order to disinfect and protect the seeds from seed-borne or soil-borne pathogenic organisms and storage insects. 3 Sheep lice and blowflies, among other parasites’ threats cause major economic loss to the wool industry [42]. Some farmers are using chemicals to prevent the contamination of its ovine. Most of these products comprises as active ingredient pesticides. Master Thesis LCA of Two Textile Products: Wool and Cotton 21 From this analysis are excluded:  The carbon dioxide equivalent uptake was not considered because: - Following the study of Eady et al. (2011), biogenic carbon that is part of the annual carbon cycle was assumed to be in equilibrium thus changes in soil and vegetation carbon in farm products were not included in the system boundary [15]; thus, in extensive pasture the majority of the vegetable materials are retained on site and it is assumed that CO2 will be released with time respecting the carbon cycle. - Cotton and wool fibre stores carbon but it is then released at end of life; - Soil carbon sequestration is not considered to be significant during periods ranging from 6 to 12 months according to Biswas et al. (2012) [13]  The production and use of bio controllers and natural pesticides due to the lack of background information and datasets to model it. For the same reasons, cow manure production is not considered within the system boundaries (but its emissions are modelled).  Emissions from the application of chemical treatments in sheep are not accounted. It is considered an output which will be released from wool and carried out in downstream processes (e.g. wastewater emissions from scouring wool).  Transports of fertilizers, pesticides and chemicals are not included as they are assumed to be transported from local retailers to farm and thus not relatively significant for the overall analysis. Figure 5 - Life cycle stages processes associated to the production of seed cotton and greasy wool. Master Thesis LCA of Two Textile Products: Wool and Cotton 22 Mechanical and chemical processes for dyed yarn production Regarding the main activities of these life cycle stages inputs and outputs from on-company and pre-company origin are included. In Figure 6 are illustrated the stages considered within the system boundaries. The modelling of these industrial systems comprises:  Chemicals, auxiliaries and packaging material production;  Energy (electricity, heat or cogeneration) production from grid or own production;  Water used (e.g. tap water, underground water and industrial water);  Wastewater and solid waste final treatment;  Air emissions;  The modes of raw material (textile products) transportation from the previous step of the supply chain to the company and correspondent impacts are accounted. Figure 6 – Life cycle stages processes associated to the mechanical and chemical processes for dyed yarn production (activities occurring after ginned cotton and greasy wool production). From the analysis are excluded:  Solid wastes which are recycled are not assessed as it is assumed as a raw material of other processes outside the system boundaries.  Transports of chemicals, auxiliaries and packaging materials are not included as they are assumed to be transported from local retailers to the suppliers and considered that low amount of fuel would be used. Following the same consideration, solid waste transports to its final disposal is not accounted. Master Thesis LCA of Two Textile Products: Wool and Cotton 23 3.2.2 Allocation process The case companies that supplied the inventory data produced a number of products and sub products. The data supplied reports to the production of all the set of products and subproducts. In order to report the specific values referring the products under study the amount of inputs and outputs (materials and energy) flows were split among the different products or by-products. Allocation is defined as partitioning the input or output flows of a process to the product system under study [10, 40]. Economic allocation was used as preferential due to the fact that in ISO 14044 [39] this allocation is suggested where physical relationship (i.e. kg, L, m2, m3, among others) cannot be established. It is assumed that economical partitioning reflects the relationships between products and by-products production. Table 9 presents the allocation factors used. Table 9 - Products (underlined) and by-products produced by the suppliers and the allocation factors used. Life cycle stage Case studies Products Allocation Factor Type WOOL Sheep Farming F1 | F2 | F3 F1 F2 F3 Greasy wool 0.30 0.62 0.81 Economical Carcases 0.70 0.23 0.13 Live Units a) 0.15 0.06 Scouring Wool top 0.85 Economical Lanolin 0.15 Spinning S3 Wool yarn 1 none S4 Wool yarn 0.96 Economical Wool noil 0.04 S5 | S6 Wool yarn 1 none Dyeing D1| D2 | D3 Wool 1 none COTTON Cotton Cultivation Conventional Organic Ginned cotton 0.60 Economical Seeds 0.37 Neps 0.03 Spinning S1 | S2 S1 S2 Cotton yarn 0.80 0.83 Economical Cotton comber 0.20 0.17 Dyeing & Bleaching D&B 2 |D&B 3 Cotton 1 none a) The supplier F1 is not selling live unit. 3.3 Inventory analysis The inventories were built using primary data made available by suppliers, secondary data was estimated based on existing models or taken from the ecoinvent databases. The suppliers reported the consumption of energy and materials used and outputs as products, by-products, solid waste and emissions (water and air) from their production Master Thesis LCA of Two Textile Products: Wool and Cotton 24 system. Some of the emissions were estimated. Models are used in the cases where measures require scientific knowledge, technology difficulty of measurement or costs (e.g. quantity of nitrate or phosphate emissions to water from fertilizers use on cotton cultivation). The ecoinvent database is used to complete and simplify the assessment, for instance, if the supplier is using 1 kg of cardboard the correspondent dataset comprises the environmental impacts associated to its production (background data). Activities such as the production of energy (electricity and heat), fertilizers, pesticides, feedstuff, chemicals and auxiliaries or the use of transports and agricultural machinery are included in the analysis through the use of ecoinvent databases. The impact is assessed by generalist databases. Models from the literature are developed to describe sheep farming and cotton cultivation emissions from applied fertilizers and pesticides as well as from livestock metabolic processes. These models are created aiming to quantify flows while being valid to different regions worldwide, and thus applicable to different kind of soils and climate regions. 3.3.1 Inventory for sheep farming Table 10 lists the main characteristics of the three assessed farms in terms of stock units (s.u.) 4 , wool production and land used. These producers use extensive models of grazing sheep in a way that its stock rate is equal or lower than 12 s.u./ha [33]. It is also visible that similar rates of greasy wool yield are obtained. These vary from 4.4 kg/s.u. (for F3) and 4.6 kg/s.u. (for F1). Table 10 – Profile of the assessed farms Farms F1 F2 F3 Sheep Stock units a), s.u. 14 500 10 500 6 500 Stock rate, s.u./ha 1.2 12 0.1 Wool production Greasy wool, kg 67 000 47 500 28 500 Yield, kg/s.u. 4.6 4.5 4.4 Land Location New Zealand Australia Australia Grazing area, ha 12 400 900 64 000 Soil type [43] Histosol Vertisol Vertisol Average slope 0.01 0.01 0.01 a) The farmers are calculating the stock units using standard and official values for their countries. 4 Stock unit’s value represents the number of sheep equivalent and it has different conversion factors according to the metabolic system of the animals (breed and age) and country or region environment. Master Thesis LCA of Two Textile Products: Wool and Cotton 25 Table 11 and Table 12 summarize, respectively, the inputs and the output flows from greasy wool production. Table 11 lists land use, energy consumption, transports, machinery, water, fertilizers, pesticides, feed and chemicals for sheep’s treatment. Table 12 lists emissions to air, water and soil. All the values are reported according to the functional unit used in this stage – 1kg of greasy wool. Table 11 – Inventory of inputs for the life cycle stage of sheep farming. Values related to the FU of 1 kg of greasy wool produced. Farms F1 F2 F3 Electricity Electricity from grid 1), kWh - 6.82E-02 1.10E+00 Electricity from own production 2), MJ 1.80E-01 6.70E-01 1.07E+01 Machinery Sowing3), ha 1.97E-04 - - Fertilizers application 3), ha 8.39E-05 3.71E-03 - Pesticides application 3), ha 5.05E-05 1.23E-04 - Harvest 3), ha 6.65E-05 - - Tractor 4), tkm 1.15E+00 - 2.81E+00 Water Irrigation 5), m3 5.71E-03 - - Sheep 6), m3 9.43E-02 2.00E-01 2.71E-01 Electricity from grid 1), kWh - 1.24E+00 1.10E-02 Electricity from own production 2), MJ - 1.07E-1 Feed 7), kg Silage 2.69E-02 - - Maize grain - 6.48E-01 - Hay - 6.48E-01 - Fertilizers7), kg - Urea ammonium nitrate 8) 2.60E-02 4.20E-02 - Single superphosphate 8) 2.66E-01 - - Monoammonium phosphate 8) - 9.09E-02 - Poultry - broilers manure, solid 8) - 1.46E+01 - Pesticides, kg 9) Paraquat - 7.00E-04 - Glyphosate - 3.78E-03 - Chemical treatments, kg 9) Chlorpyrifos 6.12E-04 - - Cryomazine - 2.49E-04 - Dicyclanil - 6.22E-05 - Abamectin - 2.59E-06 - Albendazole Oxide - 4.66E-06 - Master Thesis LCA of Two Textile Products: Wool and Cotton 32 Heavy metals are emitted to the soil when fertilizers are applied. These emissions were estimated based on the SALCA for identifying emission factors from fertilisers and uptakes from cotton. Emission and uptake factors used are presented in Table H.3, H.4 and H5 in Appendix H. The pesticides emissions were estimated by using a simplified model following the one used in the ecoinvent report Life Cycle Inventories for Bioenergy [55] as in 3.3.1 for sheep farming. In cotton cultivation this model is not only followed for pesticides applied on cotton crop but also for the pesticides used as seeds treatment. Following the same lines it is assumed that all inputs of pesticides are emitted in the nature (in soil from agriculture). 3.3.3 Inventory of mechanical and chemical processes for dyed yarn production Scouring wool, spinning, dyeing and dyeing & bleaching are modelled using similar methods. All are wet processes with the exception of spinning which generation of wastewater is pointed as small and with low content of pollutants. The input flows of these life cycle stages are presented Table 15. Master Thesis LCA of Two Textile Products: Wool and Cotton 33 Table 15 - Life cycle stage inputs for scouring, dyeing, dyeing & bleaching and spinning. Scouring Wool Dyeing Wool D&B 1) Cotton Spinning Cotton Spinning Wool D1 D2 D3 D&B 2 D&B 3 S1 S2 S3 S4 S5 S6 Energy 2), MJ 1.72E+01 5.90E+01 1.67E+01 1.21E+01 1.67E+01 1.21E+01 9.46E+00 1.32E+01 1.26E+01 3.37E+01 3.69E+00 3.57E+01 Electricity, kWh: Standard grid 6.92E-02 1.31E+00 1.66E+00 7.49E-01 1.66E+00 7.49E-01 2.19E+00 3.56E+00 2.85E+00 3.01E+00 9.70E-01 8.24E+00 Own production3) 7.84E-01a) 3.94E-01b) - - - - - - - 9.34E-01b) - - Heat 4), MJ 1.41E+01a) 5.28E+01a) 1.07E+01a) 9.36E+00b) 1.07E+01a) 9.36E+00b) 1.57E+00a) 3.59E-01c) 2.32E+00a) 1.95E+01a) 1.96E-01a) 6.00E+00a) Water, m3 4.23E-02 2.81E-01 3.67E-01 8.50E-02 3.67E-01 8.50E-02 6.90E-02 5.77E-03 1.33E-03 2.07E-02 7.32E-04 2.43E-02 Wastewater, m3 4.23E-02 2.70E-01 3.67E-01 8.50E-02 3.67E-01 8.50E-02 8.11E-02 5.77E-03 1.33E-03 1.73E-02 7.32E-04 6.41E-03 Transports 5), tkm 2.20E+01 1.53E+01 6.13E+00 4.34E+00 3.22E-01 2.80E-02 3.48E+00 6.50E+00 5.62E+00 1.53E+01 4.30E+00 5.30E+00 Sea 2.16E+01 1.51E+01 6.08E+00 4.22E+00 2.91E-01 - 1.14E-01 5.79E+00 4.73E+00 1.51E+01 4.20E+00 5.18E+00 Road 3.99E-01 1.62E-01 4.58E-02 1.19E-01 3.13E-02 2.80E-02 1.68E+00 7.09E-01 8.92E-01 1.62E-01 9.83E-02 1.18E-01 Rail - - - - - - 1.68E+00 - - - - - Packaging, kg 1.07E-02 5.98E-02 7.94E-02 2.24E-02 7.94E-02 2.24E-02 2.13E-02 8.83E-03 4.17E-02 2.31E-04 1.35E-01 2.39E-01 Cardboard - 2.50E-02 5.30E-02 1.53E-02 5.30E-02 1.53E-02 1.92E-02 8.83E-03 - 2.31E-04 1.28E-01 1.20E-01 Paper - 5.01E-04 - 2.34E-04 - 2.34E-04 - - - - - - PET 3.29E-03 4.26E-03 2.65E-02 2.86E-03 2.65E-02 2.86E-03 - - - - 6.45E-03 - Polyester - - - - - - 2.12E-03 - - - - - Polyethylene HD - 1.50E-02 - 4.03E-03 - 4.03E-03 - - - - - 1.20E-01 Polypropylene - 6.26E-03 - - - - - - 4.17E-02 - - - Steel 7.41E-03 8.76E-03 - - - - - - - - - - Chemicals, kg 9.45E-02 1.35E-01 4.03E-02 1.08E-04 1.50E-01 9.18E-05 8.00E-04 7.07E-04 2.36E-04 8.41E-03 1.10E-01 2.27E-03 Dyestuffs - 1.10E-01 2.11E-02 3.23E-02 2.97E-02 3.79E-02 - - - - - - Bleach - - - 1.58E-05 4.64E-02 - - - - - - - Paraffin waxes - - - - - - 8.00E-04 7.07E-04 - 3.00E-03 2.00E-02 2.27E-03 Lubricants 4.34E-03 - - - - - - - 2.36E-04 8.04E-04 7.00E-02 - Other auxiliaries 9.02E-02 2.42E-02 1.91E-02 9.18E-05 7.36E-02 9.18E-05 - - - 4.62E-03 2.00E-02 - Note: cells with hyphen (-) means that the particular input does not exist in the respective supplier’s activity. 1) D&B = Dyeing and Bleaching 2) Energy corresponds to the sum of electricity and thermal energy consumed by the supplier in MJ. The conversion is made from kWh to MJ using the factor of 3.6 MJ/kWh. 3) The suppliers are using as source of energy: a) hydropower and; b) cogeneration using natural gas as fuel. 4) The suppliers are using different sources of heat energy and reporting it in distinct units: a) natural gas - conversion from m3 to MJ using its calorific power of 36.3 MJ/m3 [60]; b) diesel - conversion from kg to MJ using its calorific power of 42.8 MJ/kg [60]; c) district heat (wood chips) – its figure is reported as MJ consumed. 5) These values are the result of the multiplication of the distance between suppliers (km) with the quantity transported (t). Sea distances are calculated based on the FSI (2013) where portto-port or door-to-door transit time and distances are calculated based on the statistical data, provided by shipping lines. Road and rail distances are estimated using the Google (2013). Master Thesis LCA of Two Textile Products: Wool and Cotton 34 The suppliers D3 and S1 (both located in China) do report the energy mix utilized on the production of the electricity consumed in their facilities. D3’s energy mix is composed by 81% coal, 18% solar and 1% nuclear, while S1’s mix uses 65% coal, 30% hydro and 5% solar. All the others suppliers presented are modelled regarding its country’s standard grid in ecoinvent. Electricity imports are also accounted for. Heat production is modelled according to the datasets available in the ecoinvent. The model selected refers to the boiler capacity and burner type utilized in the case studies. In the case where district heating is used the generic dataset selected according the energy source utilized (wood chips). The suppliers describe the origins of its fibres or yarns (raw materials to be processed in their facilities) as well as the type of transportation used from the previous life cycle stage to the company. The modes of transports used are sea, road and rail and distances are estimated based on tools available online. Chemicals and auxiliaries productions are modelled according to the datasets existing in the database utilized. Some assumptions are made when specific ingredients are not modelled in the databases. That way, some alternatives are adopted taking into account its similarity with other compounds or their chemical class. This is done for organic, inorganic or a mixture of both. Water emissions are listed in Table 16. The composition for the effluents is only reported by the scouring mill and dyeing mil D1 as these have internal treatment of polluted water coming from its processes. All other suppliers are releasing its wastewater for external treatment plants. For these cases, wastewater impacts are modelled using datasets for wastewater treatment plant. Table 16 – Water emissions from wet processes of scouring and dyeing wool reported as kilogram of compound per FU (wool top and dyed product, respectively). Compounds Scouring wool Dyeing wool (D1) Ammonium, NH4-N 4.86E-03 1.23E-04 BOD5 8.97E-03 7.26E-05 Chlorides, Cl3.80E-02 4.88E-04 Chromium, Cr - 2.90E-07 COD 3.09E-02 2.18E-04 Copper, Cu - 1.45E-07 Iron, Fe - 7.12E-06 Lead, Pb - 1.45E-07 Mercury, Hg - 1.45E-08 Nickel, Ni - 1.45E-07 Nitrate, NO3-N 4.00E-04 3.33E-03 Nitrite, NO2-N 2.76E-05 - Master Thesis LCA of Two Textile Products: Wool and Cotton 35 Organic nitrogen, N-org 3.28E-04 - Sulfates, SO4 - 2.71E-03 Suspended solids 1.06E-04 - Total phosphorus, P 7.18E-05 2.90E-06 Zinc, Zn - 7.26E-07 Note: cells with hyphen (-) means that the particular compound is not analysed in the internal treatment plant. That way, no value is available. Conversion factors used to convert the amount of substance reported in the inventory to the amount of substance in ecoinvent (example: ammonium-N into ammonium). These factors and datasets are listed in the Table D.3 in Appendix D. Table 17 shows the amount of solid waste generated and its final end of life option. Table 17 –Inventory of solid waste production per type of final disposal Suppliers Scourin g wool D&B Cotton Dyeing wool Spinning cotton Spinning wool D3 D1 D3 S1 S2 S4 S5 S6 kg of solid waste disposed Landfill 1.75E-02 - 3.65E-02 - 1.60E-03 - 2.06E-03 6.02E-03 - Incineration - 7.81E-04 - 7.81E-04 2.53E-03 1.24E-02 - - - Incineration of hazardous waste - 9.76E-06 - 9.76E-06 4.49E-04 - - - 1.69E-03 Note: cells with hyphen (-) correspond to end of life options which are not utilised for disposal of the solid waste generated according to the suppliers’ data. Solid waste is regarded according to its final treatment and modelled by generic dataset. Solid wastes which are recycled are not assessed as it is assumed as a raw material of other processes outside of the system boundaries. Only the supplier S2 is reporting its emissions to air resulting from the spinning processes. These emissions are listed in Table 18. Air emissions are generally collected and emitted in mixture with other air emissions from other processes, as for example the exhaustion of combustion gases from boilers. Thus, it is not easily reported the allocation of the emissions of specific processes as for instance, dyeing, spinning or scouring. As only one supplier is reporting emissions form its specific processes and only two compounds are analysed, these values are not concerned in the LCA. It is assumed that the most important emissions emerge from processes of heat and electricity production as well as transports. Table 18 – Air emissions from the spinning mill S2. Values reported to the functional unit of 1 kg of cotton yarn Compounds Spinning mill S2 Chlorine and inorganic compounds, HCl 1.30E-03 Dust 4.34E-04 Master Thesis LCA of Two Textile Products: Wool and Cotton 36 3.3.4 Datasets from ecoinvent Secondary data from ecoinvent used to model the life cycle stages presented are listed in the Appendix A to G. Table 19 summarizes the datasets included in the listed Appendixes. Table 19 – Location of the datasets utilized in the appendixes. Category Sub-category Appendix Table Energy production Electricity A A.1 Heat A.2 Agriculture Machinery B B.1 Feedstuff B.2 Fertilizers B.3 Pesticides B.4 Chemical treatments (sheep and seeds) B.5 Emissions B.6 Packaging material - C C.1 Water Sources of consumed water D D.1 Wastewater treatment D.2 Water emissions D.3 Chemicals, dyestuffs and auxiliaries - E E.1 Transports - F F.1 Solid waste disposal - G G.1 3.4 Impact assessment Environmental impacts are quantified using the LCA tool and respecting the guidelines reported in the ISO 14040:2002 [10]. This work performs LCIA until characterization step and following the EcoLogTex the methods used are from taken from ILCD recommendations [11]. This method was chosen because it is a result of a project for the European Commission that analysed several life cycle impact assessments (LCIA) methodologies to reach and recommend a consensual methodology [11]. Thus, the potential environmental impact categories assessed were:  Climate change: Global Warming Potential calculating the radiative forcing over a time horizon of 100 years. | IPCC 2007.  Ozone depletion: Ozone Depletion Potential (ODP) calculating the destructive effects on the stratospheric ozone layer over a time horizon of 100 years. | World Meteorological Organization (WMO) 1999.  Human toxicity, (cancer effects and non-cancer effects): Comparative Toxic Unit for humans (CTUh) expressing the estimated increase in morbidity in the total human population per unit mass of a chemical emitted (cases per kilogramme). | USEtox. Master Thesis LCA of Two Textile Products: Wool and Cotton 37  Acidification: Accumulated Exceedance (AE) characterizing the change in critical load exceedance of the sensitive area in terrestrial and main freshwater ecosystems, to which acidifying substances deposit. | Seppälä et al. 2006 and Posch et al. 2008.  Freshwater eutrophication: Expression of the degree to which the emitted nutrients reaches the freshwater end compartment (phosphorus considered as limiting factor in freshwater). | ReCiPe version 1.05.  Marine eutrophication: Expression of the degree to which the emitted nutrients reaches the marine end compartment (nitrogen considered as limiting factor in marine water). | ReCiPe version 1.05.  Freshwater ecotoxicity: Comparative Toxic Unit for ecosystems (CTUe) expressing an estimate of the potentially affected fraction of species (PAF) integrated over time and volume per unit mass of a chemical emitted (PAF m3 year/kg). | USEtox.  Water resource depletion: Freshwater scarcity: Scarcity-adjusted amount of water used. | Swiss Ecoscarcity 2006. Master Thesis LCA of Two Textile Products: Wool and Cotton 38 Master Thesis LCA of Two Textile Products: Wool and Cotton 39 4 RESULTS AND DISCUSSION Here the results for the different life cycle stages are presented and discussed for each textile product. Moreover, the results obtained for each supplier for the same life cycle stage are compared, the burdens are identified and the opportunities of improvements suggested. The presentation of the results is divided in two phases according to the materials assessed. At first the results for wool yarns production (including sheep farming, scouring, spinning and dyeing) are presented. These are followed by the results for cotton yarn manufacture (including cotton cultivation, spinning and dyeing & bleaching). 4.1 LCA of Wool Yarns 4.1.1 Sheep farming The contribution to the total impact of greasy wool production from each farm is shown in Table 20 for F1, F2 and F3. In order to highlight the representativeness of each supplier for each environmental impact category assessed it is calculated the relative contribution. This is done by dividing the contribution of each supplier by the maximum value calculated for each impact category as show in the table. Table 20 – Results from sheep farming (case study: F1, F2, F3) for the production of 1 kg of greasy wool and its relative contribution to the maximum value calculated for each category. Impact Category F1 F2 F3 Relative contribution, % F1 F2 F2 Climate change, kg CO2 eq 2.11E+01 4.39E+01 5.76E+01 37a) 76 100 Ozone depletion, kg CFC-11 eq 9.51E-08 3.34E-07 2.55E-07 28 100 76 Human toxicity (CE) b), CTUh 6.01E-08 4.31E-08 1.19E-09 100 72 2 Human toxicity (NCE) b), CTUh 3.81E-05 9.07E-05 2.62E-06 42 100 3 Acidification, molc H+ eq 5.39E-01 1.09E+00 8.21E-01 50 100 76 Freshwater eutrophication, kg P eq 5.84E-04 2.08E-03 2.21E-04 28 100 11 Marine eutrophication, kg N eq 1.82E-02 5.55E-02 3.89E-02 33 100 70 Freshwater ecotoxicity, CTUe 1.23E+01 5.12E+01 1.55E+00 24 100 3 Water resource depletion, m3 water eq 1.68E-02 3.40E-02 4.42E-02 38 77 100 a) Example of the procedure performed for the calculation of the relative contribution of each supplier in all the categories: for F1 in the climate change category = 2.11E+01 / 5.76E+01 * 100. b) CE = cancer effects; NCE = non-cancer effects Master Thesis LCA of Two Textile Products: Wool and Cotton 40 The sheep farmer F2 has the largest impacts for six categories out of 9 calculated, namely for the ozone depletion, human toxicity (non-cancer effects), acidification, eutrophication (freshwater and marine) and freshwater ecotoxicity. This supplier has the second largest contribution in the other categories (climate change, human toxicity (cancer effects) and water resource depletion). F2’s has a larger input of fertilizers, pesticides and chemical treatments to sheep. This activity has also a substantial use of machinery and electricity. No fertilizers, chemicals nor pesticides and chemicals are utilized by F3 but it reports a high consumption of energy and use of tractor on its activities. These reflect its large results in categories such as climate change, ozone depletion, acidification and marine eutrophication while having low contribution in human toxicity (cancer and non-cancer), freshwater eutrophication and freshwater ecotoxicity categories. As a big area is used by this supplier the use of tractor to cover all the fields is higher. F1’s burdens are mostly in between F2 and F3 in the overall results. Exceptions are made for climate change, ozone and water resource depletion in which it has the lowest potential impacts and in human toxicity (cancer effects) where this supplier has the highest contribution. The relative contribution of each activity to the total impact on cotton fibre production is illustrated in Figure 7. Master Thesis LCA of Two Textile Products: Wool and Cotton 41 Figure 7 - Relative contribution of each activity to the overall impact for F1, F2 and F3 for the production of 1kg of greasy wool. Sheep farming processes were evaluated and its contribution for the environmental impacts is presented per kilogram of greasy wool at farm. Burdens have been grouped as listed:  Field Emissions: estimated releases of fertilizer and pesticides as well as livestock emissions to the air, water or soil.  Feedstuff: production of seeds and chemicals utilized for their treatments.  Pesticide & Chemicals: it includes the production of the pesticides utilized as well as the chemicals used for sheep treatment (which include also pesticides).  Fertilizers: it includes the production of the fertilizers used.  Machinery: this group comprises the machinery used on pasture activities as sowing, fertilizer and pesticide application as well as the utilization of a tractor on transports through the farm of people, assets and flock movements; including its consumption of diesel and emissions.  Electricity: generation of electricity in power plant and generation set for farming activities as shearing, lightning, workshop and other activities related to sheep farming.  Water: water used for irrigation and sheep watering as well as energy associated with its application. 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% F3 F2 Water res. depletion: F1 F3 F2 Freshwater ecotox.: F1 F3 F2 Marine eutroph.: F1 F3 F2 Freshwater eutroph.: F1 F3 F2 Acidification: F1 F3 F2 Human toxicity (NCE): F1 F3 F2 Human toxicity (CE): F1 F3 F2 Ozone depletion: F1 F3 F2 Climate change: F1 Field Emission Fertilizers Machinery Electricity Feedstuff Pesticides & Chemicals Water Master Thesis LCA of Two Textile Products: Wool and Cotton 48 Figure 9 - Relative contribution of each activity to the overall impact for spinning mills for the production of 1 kg of yarn. Spinning mill activities were evaluated and its contribution for the environmental impacts is presented per kilogram of spun wool or wool yarn at spinning mill gate. Burdens have been grouped by its origins as listed:  Water & Wastewater: consumption of water from aqueduct or well and wastewater treatment in a municipal plant.  Chemicals: production of chemicals and auxiliaries utilized. 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% S6 S5 S4 Water res. depletion: S3 S6 S5 S4 Freshwater ecotox.: S3 S6 S5 S4 Marine eutroph.: S3 S6 S5 S4 Freshwater eutroph.: S3 S6 S5 S4 Acidification: S3 S6 S5 S4 Human toxicity (NCE): S3 S6 S5 S4 Human toxicity (CE): S3 S6 S5 S4 Ozone depletion: S3 S6 S5 S4 Climate change: S3 Electricity Packaging Transports Water & Wastewater Heat Chemicals Solid Waste Master Thesis LCA of Two Textile Products: Wool and Cotton 49  Packaging: manufacture of packaging materials used to pack the products as well as plastic or cardboard cones utilized to give shape or support the yarns.  Electricity: generation of electricity in power plant or own facilities.  Heat: production of heat from natural gas in boilers to be used in the spinning.  Transports: transport of fibres to be spun from scouring mills to spinning mills.  Solid waste: disposal of the solid waste generated. The main contributor in climate change and ozone depletion is electricity production. It emerges as the major origin of its impacts in most of the suppliers (up to 85%) while heat production is the larger hotspot in the supplier S4. Activities as packaging and chemicals production are a significant contribution (around 15%) in the spinning mill S3. Human toxicity categories have different key origins for its burdens in each supplier but electricity is always sharing significant contributions (ranging from 20% in S5 to 50% in S3 and S6). Human toxicity (cancer effects) is mainly originated by contributions around 35% in S3 and S6 and 25% in S4 from packaging production but also contributions from chemicals production in the supplier S4 and S5 (30% and 50% respectively). Water and wastewater have an important share in S4 around 30%. In the environmental impact category of human toxicity (non-cancer effects) electricity keeps being the largest contributor for the suppliers S3 and S6 (around 60%), while the major contributors in S4 and S5 are water & wastewater (45%) and packaging materials production (65%). The environmental impact of electricity generation is the key contributor in the category of acidification. It shows up contributions larger than 55% in all the spinning mills assessed, Transports also have important shares (up to 25%). A similar pattern of contributions is verified in marine eutrophication where electricity has smaller impacts and transports’ contribution is now up to 35%. Freshwater eutrophication is mainly originated by electricity production as well. 20% of its contribution in this category is coming from water & wastewater in the supplier S4 and packaging in the supplier S5. Freshwater ecotoxicity has a similar pattern as the one verified for the category of human toxicity (non-cancer effects). In the category of water resource depletion the major contributors are electricity production for S3 and S4 and packaging production for S5 and S6. Packaging also has an important contribution in the environmental performance of S3 (up to 30%). The use of fossil fuels in power plants, boilers as well as in engines of transports is responsible for several negative impacts in the environment mainly due to the release of greenhouse gases and heavy metals. Examples of exhaust gases coming from its combustion and correspondent impacts are CO2, CH4 and N2O emissions which contributes most to the Master Thesis LCA of Two Textile Products: Wool and Cotton 50 climate change and SO2 and NOx that have important burdens on acidification due to the potential formation of sulphuric and nitric acid. The consumption of these fuels is also associated to the emissions of heavy metals from burning coal and light fuels processes as well as from the generation of mining spoils from its extraction. Example of these toxic compounds which are released to air, water and soil are chromium, mercury, lead and zinc which contributes most to the categories of human toxicity and freshwater ecotoxicity. As mentioned before ozone depletion emissions today are usually minimal and related to electricity production. In the present case it is systematic burden with origin on the processing of natural gas and the main actors are halons, HCFC’s and CFC’s. Other important shares of electricity on environmental impact are in eutrophication: while mining activities also generates the emissions of nutrients as phosphates which contributes most to freshwater eutrophication, NOx and ammonia from exhaust gases increases the potential impact of marine eutrophication. Chemicals and packaging material have important impacts on ozone depletion in the supplier S5 as in its production energy is consumed but also direct releases of ozone depletion contributors. Emissions of heavy metals and losses of pesticides and fertilizers from agricultural processes in upstream activities of the cardboard production are the mains origins of its contributions. The major contributor for the overall results is electricity. Packaging emerges as a significant contributor in categories as human toxicity, freshwater eutrophication and water resource depletion (mainly in the supplier S5 but also in S6). Transports have important contributions (up to 30%) in ozone depletion, acidification and marine eutrophication. Chemicals production has impact in the overall results of S4 and S5. The spinning mill S4 is producing more heat and wastewater than the others, that way it is a hotspot in the categories of climate change, ozone depletion and water resource depletion for the latter driver. Solid waste accounts for not more than 3% of the impacts in all indicators. The spinning activity has very low direct impacts, as direct emissions from this activity are almost none. The main drivers for the environmental impacts of spinning mills are activities which happen in upstream processes like e.g. electricity production. Therefore, possible improvements are mainly depending on the supplier management. The S3 and S5 companies, which are having relative impacts, are reporting consumption levels of electricity and heat as the ones reported as an average in literature: 1 to 3 kWh/kg of electricity and 1 to 5 MJ/kg of thermal energy. The heat used in S5 is 10 times lower than the minimum reported while in S4 it is almost 3 times higher. Regarding the LCI of this energetic consumption values, higher improvements might be needed in S4 in terms of heat Master Thesis LCA of Two Textile Products: Wool and Cotton 51 and in S6 in terms of electricity consumption. That way, improvements in the overall results may be achieved. 4.1.4 Dyeing The contribution of each driver to the total impact in the three dyeing mills is shown in Table 1Table 23. Similarly to the previous results, in order to compare the relative contribution of each mill the relative contribution of the suppliers per environmental impact category is calculated dividing its contribution by the maximum value calculated for each category (example of the calculus provided in the table). Table 23 - Results of dyeing mills activity for the production of 1 kg of dyed yarn and its relative contribution to the maximum value calculated for each category. Impact category D1 D2 D3 Relative Contribution D1 D2 D3 Climate change, kg CO2 eq 5.36E+00 2.15E+00 1.84E+00 100 40 34 Ozone depletion, kg CFC-11 eq 7.01E-07 2.50E-07 1.40E-07 100 36 20 Human toxicity (CE), CTUh 1.92E-08 3.11E-08 1.04E-08 62 100 34 Human toxicity (NCE), CTUh 2.75E-07 7.00E-07 1.91E-07 39 100 27 Acidification, molc H+ eq 1.53E-02 1.06E-02 1.41E-02 100 69 92 Freshwater eutrophication, kg P eq 1.68E-04 3.73E-04 1.09E-04 45 100 29 Marine eutrophication, kg N eq 6.26E-03 8.88E-03 3.38E-03 71 100 38 Freshwater ecotoxicity, CTUe 6.09E-01 1.02E+00 3.25E-01 59 100 32 Water resource depletion, m3 water eq 4.63E-02 6.53E-02 1.61E-02 71 100 25 a) Example of the procedure performed for the calculation of the relative contribution of each supplier in all the categories is: for D3 in the climate change category = 1.84E+00 / 5.36E+00 * 100. The supplier D2 has the highest impacts in most of the categories and is the second largest contributor in climate change and ozone depletion after the suppliers D1 and has the lowest share in the category of acidification where D1 is the main contributor. D3 is the dyeing mill which has the lowest shares in most of categories. Dyeing mills activities were evaluated and its contribution for the environmental impacts is presented per kilogram of dyed and bleached yarn at factory gate. Burdens have been grouped along the lines of what has been done with the spinning mills. In this case the group Chemicals also comprises the production of dyestuffs and bleach. The relative contribution of each driver to the total impact on cotton fibre production is illustrated in Figure 10. Master Thesis LCA of Two Textile Products: Wool and Cotton 52 Figure 10 - Relative contribution of each activity to the overall impact for dyeing mills (D1, D2 and D3) for the production of 1 kg of dyed yarn. The main contributors to climate change and ozone depletion are heat and electricity production, having shares up to 85% and 50% respectively. Electricity generation also has burdens larger than 35% in acidification, being the key contributor to this category. Water and wastewater emerges as the key factor for the environmental burdens in all the other categories (human toxicity, eutrophication, freshwater ecotoxicity and water resource depletion) with relative contributions ranging from 40% for freshwater ecotoxicity to 98% for water resource depletion. Chemicals and transports have meaningful shares in the overall results while solid waste doesn’t account for more than 1%. Most of the climate change burdens are shared between electricity and heat production due to the release to air of CO2, CH4 and N2O from fossil fuels combustion. The same drivers have a similar share in Ozone Depletion due to the emission of halon, HCFC’s and CFC’s in upstream activities of natural gas and light fuel processing. Electricity in D3 has small share on the ozone depletion as its production mix is strongly based on coal which processing has smaller emissions of CFC’s. Air emissions of SO2 and NOx originated in power plants, boilers 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% D 3 D 2 Water res. depletion: D 1 D 3 D 2 Freshwater ecotox.: D 1 D 3 D 2 Marine eutroph.: D 1 D 3 D 2 Freshwater eutroph.: D 1 D 3 D 2 Acidification: D 1 D 3 D 2 Human toxicity (NCE): D 1 D 3 D 2 Human toxicity (CE): D 1 D 3 D 2 Ozone depletion: D 1 D 3 D 2 Climate change: D 1 Water & Wastewater Heat Electricity Chemicals Packaging Transports Solid Waste Master Thesis LCA of Two Textile Products: Wool and Cotton 53 and transports from the burning of fossil fuels originate big burdens in the acidification results. Human toxicity (cancer and non-cancer effects) and freshwater ecotoxicity are mainly affected by heavy metals emissions to air, water and soil from wastewater emissions and treatment but also from upstream processes related to the electricity production. Chromium, mercury, zinc and lead are the main pollutants which conduct these impacts. The production of packaging cardboard has some impact in freshwater ecotoxicity due to agriculture activities (pollutants releases due to losses of fertilizers and pesticides) while wire production is related to heavy metal emissions from its manufacture. Chemicals production also has an important contribution in categories as human toxicity (cancer effects) and acidification. While in the first it is verified because of chromium and mercury emissions from electricity produced (upstream) and disposal of solid wastes generated, in the second it is due sulphur dioxide, nitrogen oxides and ammonia to air from its production processes. Freshwater eutrophication is mainly caused by phosphate emissions from wastewater emissions and the disposal of spoil from coil and lignite mining in upstream processes of electricity production. Marine eutrophication is most related to emissions of NOx to air from electricity production (combustion of fossil fuels) and emissions of nitrates and ammonia (ion) to water from wastewater emissions. As dyeing consumes high quantities of water and consequently generates big amounts of wastewater, strong effects of Water & Wastewater are verified in the categories of human toxicity (cancer and non-cancer effects), eutrophication (freshwater and marine), freshwater ecotoxicity end, of course, water resource depletion. Energy consumption (mainly heat but also electricity) is most of the times associated with water use in the textile industry. This is a major issue in the potential impact categories of climate change, ozone depletion and acidification. Comparing the inventory data for electricity, heat and water consumption per kilogram of dyed product with the energy use BAT values presented in section 2.4.2.  The dyeing mill D1 has the highest consumptions patterns. It corresponds to 1.7 kWh against those 0.8 to 1.1 kWh in BAT and is using 3 times more energy and 5 times more water than the referenced maximum values.  The dyeing mill D2 is consuming similar amount of electricity as D1 and 7 times more water than the referred on BAT while is consuming 11 MJ of energy that is lower than the referenced range of 13 to 16 MJ. Master Thesis LCA of Two Textile Products: Wool and Cotton 54  D3‘s electricity consumption is equal to minimum in the literature (0.8 kWh) and the supplier is using 9 MJ of energy (lower than the in BAT). However its water consumption (around 80 L) is bigger than the reported 15 to 50 litres. Water & Wastewater activities are the main problems associated with dyeing. The establishment of a roadmap fixing targets and procedures to reduce its consumption shall provide opportunities to improve the overall results. Electricity and heat are also important drivers due to the extraction, processing and use of non-renewable sources of energy for energy production. It is expected that saves on the quantity used of water might reduce the energy needs. 4.2 LCA of Cotton Yarns 4.2.1 Cotton cultivation The contribution of each driver to the total impact on cotton fibre production from both case studies (conventional and organic cotton productions) is shown in Table 24. Similarly and to compare the relative contribution of each cotton grower, its contribution is divided by the maximum value calculated for each category. Table 24 - Results from cotton cultivation (conventional and organic) for the production of 1 kg of ginned cotton and its relative contribution to the maximum value calculated for each category. Impact category Conventional Organic Relative contribution, % Conventional Organic Climate change, kg CO2 eq 2.93E+00 5.97E-01 100 20 a) Ozone depletion, kg CFC-11 eq 2.09E-07 3.10E-08 100 15 Human toxicity, cancer effects, CTUh 2.04E-08 2.24E-08 91 100 Human toxicity, non-cancer effects, CTUh 4.62E-06 2.10E-05 22 100 Acidification, molc H+ eq 2.04E-02 6.06E-03 100 30 Freshwater eutrophication, kg P eq 2.19E-03 2.01E-03 100 92 Marine eutrophication, kg N eq 4.58E-02 6.15E-04 100 1 Freshwater ecotoxicity, CTUe 2.83E+01 1.13E+01 100 40 Water resource depletion, m3 water eq 1.29E+00 9.38E-01 100 73 a) Example of the procedure performed for the calculation of the relative contribution of each supplier in all the categories is: for organic in the climate change category = 5.97E-01 / 2.93E+00 * 100. The organic cotton grower shows lower contributions for the overall results. This fact is justified by the low use of machinery and no consumption of pesticides. This organic cotton culture also has highest yield of production when compared with the conventional production process. That way, it is producing more with fewer inputs. Nevertheless, the organic cotton cultivation has higher burdens in human toxicity categories, This is because the emissions of heavy metals in soil are bigger when compared with the Master Thesis LCA of Two Textile Products: Wool and Cotton 55 conventional grower. According to the study from Tewolde et al., (2011 [64], applying poultry litter might increase soil Zn by about 59% and soil Cu by 134% relative to applying ammonium nitrate. The concentrations of heavy-metal contents of synthetic and organic fertilizers utilized to model these emissions are summarized in Table H.3 and H.4 in the Appendix H, respectively. The relative contribution of each activity to the total impact on cotton fibre production is illustrated in Figure 11. Figure 11 - Relative contribution of each activity to the overall impact for 1 kg of conventional and organic cotton production. Cotton cultivation processes were evaluated and its contribution for the environmental impacts is presented per kilogram of cotton fibre after ginning. Burdens have been grouped by its causes as listed:  Field Emissions: estimated losses of fertilizer and pesticides to air, water or soil.  Cotton Seeds: production of seeds and chemicals utilized for their treatments.  Irrigation: water used for irrigation as well as the energy associated.  Pesticides: it includes the production of the pesticides used.  Fertilizers: it includes the production of the fertilizers used.  Machinery: this group comprises the machinery used in the cultivation of cotton (e.g., seeding, fertilizer and pesticide application) as well as the utilization of a tractor on transports through the farm of people and assets related to the cotton production. 0% 20% 40% 60% 80% 100% Org. Water res. depletion: Conv. Org. Freshwater ecotox.: Conv. Org. Marine eutroph.: Conv. Org. Freshwater eutroph.: Conv. Org. Acidification: Conv. Org. Human toxicity (NCE): Conv. Org. Human toxicity (CE): Conv. Org. Ozone depletion: Conv. Org. Climate change: Conv. Field Emissions Fertilizers Irrigation Machinery Ginning Cotton Seeds Pesticides Master Thesis LCA of Two Textile Products: Wool and Cotton 56  Ginning: transport from field to the ginning mill, processing through the cotton gin, packaging materials production (bale bags and ties) and packaging process. Most of the climate change contribution is due to fertilizer production processes (50%) followed by field emissions (15%) and machinery operations (13%). Emissions of N2O are the main reason behind these results. The fertilizers production is the dominant sponsors to the category of ozone depletion in the conventional supplier (55%) and is the second main contributor in the organic supplier (40%) following Irrigation (60%). Other important contributions in conventional grower are the machinery operations which are consuming diesel. These shares are related to the release of halons, HCFC’s and CFC’s from electricity production in upstream processes. As mentioned in 0, nowadays, most of the ozone depleting chemicals is related to electricity production (mainly from production and refinement of fuels.). Field emissions were identified to be a major contributor for impact categories such as human toxicity, freshwater eutrophication and freshwater ecotoxicity (relative contributions are higher than 80%). This result is also verified in marine eutrophication in the organic cotton supplier. Fertilizers production process is in itself a source of NH3 and NOx emissions and which are contributing most to the impact category of acidification. This category is also strongly affected by the emissions of NH3 and NOx from field (25%). Machinery operations consume fuel and thus it is a source of NOx emissions which also contributes to potential acidification in the conventional cotton production (20%). Upstream activities related to electricity generation reflect the contribution from irrigation (20% in organic grower) and ginning activities. Cotton seeds, pesticides, machinery and ginning do not account for more than 10 to 20% of the impacts for all indicators. An exception is made to the machinery use in the organic grower which represents around 25% of the contribution to the ozone depletion potential. Literature values for conventional production of cotton for CO2 eq emission are 2 and 3 kilograms [27, 36] These are similar to the values here calculated. However, when the field emissions are compared with results from [36], it is possible to conclude that they are 10% lower and the production fertilizers have higher contributions. Field application of fertilizers was the main contributor to the environmental impact in the categories of human toxicity (cancer and non-cancer effects) and freshwater ecotoxicity based on its emissions of heavy metals as chromium, cadmium, nickel lead and zinc to soil. Emissions from pesticides to the soil as prometryn and lambda cyhalothrin are also important contributors in the freshwater ecotoxicity category. Master Thesis LCA of Two Textile Products: Wool and Cotton 57 Freshwater and marine eutrophication main source is in field emissions. In the first case it is verified mainly from phosphorous and phosphate emissions to water and in the second by the releases of nitrates to water as well as nitrous oxide, nitrogen oxides and ammonia to air. The organic cotton production has an impact in Marine Eutrophication 74 times lower as its field emissions are lower due to the efficient management of the nitrogen nutrient application. Land use and water consumption not surprisingly a burden directly related to the cotton cultivation. These categories are linked to the yield of production, each means that for the presented studies higher yields have less needs of land and water. Nevertheless, to have higher yields using similar amounts of water, a proper drainage system, efficient irrigation and use of organic fertilizer are needed. Field emissions are a larger contributor to several environmental impact categories: human toxicity and freshwater ecotoxicity due to the use of pesticides and eutrophication was strongly influenced by nitrate and phosphorus emissions. Acidification potential was influenced by ammonia and nitrogen oxides and climate change was influenced by nitrous oxide. Precision management of nitrogen fertilizer will continue to be a high priority for the cotton producers around the world. Fertilizer production is another important issue on climate change, ozone depletion, and acidification. Nitrogen fertilizer represents a major burden in the conventional grower cultivation while organic fertilizers in the organic cultivation. It reinforces the need for a careful management of nutrients applications to the soil (mainly of nitrogen). 4.2.2 Spinning The contribution of each driver to the total impact in the two spinning mills that are processing cotton is presented in Table 25. The calculation allowing for the comparison of the relative contribution of each mill for each impact category is performed. Table 25 - Results of spinning activity of each case study for the production of 1 kg of yarn and its relative contribution to the maximum value calculated for each category Impact category S1 S2 Relative contribution, % S1 S2 Climate change, kg CO2 eq 2.50E+00 7.07E-01 100 28a) Ozone depletion, kg CFC-11 eq 7.22E-08 9.74E-08 77 100 Human toxicity, cancer effects, CTUh 1.38E-08 3.01E-09 100 22 Human toxicity, non-cancer effects, CTUh 2.37E-07 4.09E-08 100 17 Acidification, molc H+ eq 2.64E-02 5.41E-03 100 20 Freshwater eutrophication, kg P eq 1.10E-04 5.11E-05 100 47 Marine eutrophication, kg N eq 5.30E-03 1.29E-03 100 24 Freshwater ecotoxicity, CTUe 4.51E-01 1.63E-01 100 36 Master Thesis LCA of Two Textile Products: Wool and Cotton 64 5.1.1 Wool yarns The whole set of all the possible combinations to model the yarns from wool are presented in Table 27 and the results are plotted in Figure 15. Table 27 - Number of combinations possible for the production of dyed wool yarns. Combinations Suppliers W 1 F1  Scouring Wool  S3  D1 W 2 F1  Scouring Wool  S4  D1 W 3 F1  Scouring Wool  S5  D1 W 4 F1  Scouring Wool  S6  D1 W 5 F1  Scouring Wool  S3  D2 W 6 F1  Scouring Wool  S4  D2 W 7 F1  Scouring Wool  S5  D2 W 8 F1  Scouring Wool  S6  D2 W 9 F1  Scouring Wool  S3  D3 W 10 F1  Scouring Wool  S4  D3 W 11a) F1  Scouring Wool  S5  D3 W 12 F1  Scouring Wool  S6  D3 W 13 F2  Scouring Wool  S3  D1 W 14 F2  Scouring Wool  S4  D1 W 15 F2  Scouring Wool  S5  D1 W 16 F2  Scouring Wool  S6  D1 W 17 F2  Scouring Wool  S3  D2 W 18 F2  Scouring Wool  S4  D2 W 19 F2  Scouring Wool  S5  D2 W 20 b) F2  Scouring Wool  S6  D2 W 21 F2  Scouring Wool  S3  D3 W 22 F2  Scouring Wool  S4  D3 W 23 F2  Scouring Wool  S5  D3 W 24 F2  Scouring Wool  S6  D3 W 25 F3  Scouring Wool  S3  D1 W 26 F3  Scouring Wool  S4  D1 W 27 F3  Scouring Wool  S5  D1 W 28 F3  Scouring Wool  S6  D1 W 29 F3  Scouring Wool  S3  D2 W 30 F3  Scouring Wool  S4  D2 W 31 F3  Scouring Wool  S5  D2 W 32 F3  Scouring Wool  S6  D2 W 33 F3  Scouring Wool  S3  D3 W 34 F3  Scouring Wool  S4  D3 W 35 F3  Scouring Wool  S5  D3 W 36 F3  Scouring Wool  S6  D3 a) Best case scenario b) Worst case scenario Master Thesis LCA of Two Textile Products: Wool and Cotton 65 Figure 15 - Results for wool yarn combinations 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Climate change Ozone depletion Human toxicity (CE) Human toxicity (NCE) Freshwater eutrophication Marine eutrophication Freshwater ecotoxicity Water resource depletion W1 W2 W3 W4 W5 W6 W7 W8 W9 W10 W11 W12 W13 W14 W15 W16 W17 W18 W19 W20 W21 W22 W23 W24 W25 W26 W27 W28 W29 W30 W31 W32 W33 W34 W35 W36 Master Thesis LCA of Two Textile Products: Wool and Cotton 66 In general the raw fibre production is the major contributor to the overall results except in ozone depletion and water resource depletion. Combinations which are using the supplier F2 present the worst results in most of the impact categories (ozone depletion, human toxicity (NCE), freshwater eutrophication, marine eutrophication and freshwater ecotoxicity), F3 in climate change and water resource depletion and F1 in human toxicity (CE). The lowest results are observed in four distinct categories in the suppliers by F1 and F3 namely in climate change, ozone depletion, marine eutrophication and water resource depletion for the first one and in human toxicity (cancer and non-cancer effects), freshwater eutrophication and freshwater ecotoxicity. When the suppliers S6 and D2 are combined (yarn 8, 20 and 32) the largest contributions are observed in most of the environmental categories. While the combination of the companies S6 and D1 (yarn 4, 16 and 28) with the assessed sheep farmers (F1, F2 and F3) originates the major contributors for climate change and ozone depletion. On the other hand when S5 and D3 are combined (yarn 11, 23 and 35) with each one the sheep farmers the best results are achieved in all the impact categories analysed. 5.1.2 Cotton yarns Table 28 lists the number of combinations possible to model the cotton yarns and its results are illustrated in Figure 16. Table 28 - Number of combinations possible for the production of dyed cotton yarns Combinations Suppliers C 1 Conventional  S1  D&B 2 C 2 Conventional  S2  D&B 2 C 3 Conventional  S1  D&B 3 C 4 Conventional  S2  D&B 3 C 5 Organic  S1  D&B 2 C 6 Organic  S2  D&B 2 C 7 Organic  S1  D&B 3 C 8 Organic  S2  D&B 3 Master Thesis LCA of Two Textile Products: Wool and Cotton 67 Figure 16 - Results for cotton yarn combinations. As raw fibre production is the major contributor in the overall results the results are mainly influenced by this life cycle stage. That way the combinations for conventional cotton yarns (1, 2, 3 and 4) have the largest contributions in the overall results with the exception in the environmental impact category of human toxicity (cancer and non-cancer effects) due to the use of organic fertilizers as mentioned in 4.2 and freshwater eutrophication due to the water emissions in D&B 2. When the suppliers S1 and D&B 2 are joint (yarn 1 and 5) the impacts are higher in most of the impact categories. For both cottons origins (conventional and organic) the lowest contributions are found when the supplier S2 and D&B 3 are combined (yarn 4 and 8). In the following two cases are analysed: best and worst. Then, the life cycle stages of these materials are assembled in order to create a supply chain from raw fibre to dyed yarn production. This is done for wool and cotton products. 5.2 Analysing the best and worst results from scenarios The best and worst case scenarios have been selected according to the results of the possible combinations achieved in the present chapter and assuming that the best and worst comprise a general behaviour. This, however, is not the ideal selection because there are some impact categories which scores are not the best or the worst ones (e.g. the spinning mill S2 has the lowest contributions in the overall results but it has a larger contribution in the impact category of ozone depletion). 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% C1 C2 C3 C4 C5 C6 C7 C8 Master Thesis LCA of Two Textile Products: Wool and Cotton 68 Here, just the conventional cotton product is assessed so as organic cotton product’s results are only commented based on its life cycle stage results. As only one supplier for conventional cotton and scouring is studied, its results are equal in both cases (best and worst). Table 29 lists the case that perform best and worst for wool and cotton. Table 29 – Selected suppliers to draw the wool and cotton supply chains for each one of the defined cases: best and worst. Combination Material Performance in impact categories Suppliers W 11 Wool Best F1ScouringS5D3 W 20 Worst F2ScouringS6D2 C 4 Cotton Best ConventionalS2D&B 3 C 1 Worst ConventionalS1D&B 2 The best farm (F1) was selected based on a simple criteria analysis where each impact category was assumed to have the same weight and which calculus are explained in the Appendix I. 5.2.1 Wool yarns Figure 17 illustrates the results for the three selected case scenarios for the production of dyed wool yarns and Figure 18 the relative contribution of each life cycle stage. Figure 17 – LCA results for the worst and best cases studied for wool dyed yarn production. Results for the production of 1 kg of dyed yarn. As might be observed there is a considerable potential of improvement (around 50%) in the overall results for the worst case scenario. An exception is made for the impact category of human toxicity (cancer effects) for which the two cases have similar results. A potential improvement might be expected if no fertilizers and pesticides would be used during the life cycle stage of sheep farming as in the supplier F3. 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Worst Best Master Thesis LCA of Two Textile Products: Wool and Cotton 69 Figure 18 – Relative contribution of each life cycle stage to the total impact in the wool case scenarios: worst and best. Results for the production of 1 kg of dyed yarn. Sheep farming emerges as the main contributor in most of the environmental impact categories except in ozone depletion (all cases) and water resource depletion (worst case). Ozone depletion has important contributions coming from the four life cycle stages. This category is highlighted by spinning in worst case and by scouring in the best case. Water resource depletion is a characteristic burden associated to dyeing and secondly to sheep farming. Comparing the results from the scouring, spinning and dyeing activities it is verified that:  In the worst scenario spinning is the major contributor in climate change, ozone depletion and acidification mainly due to electricity related activities while dyeing is the main contributor in the rest of the categories because of energy used to warm bowls, water consumption and emissions.  In the best scenario spinning has very low contributions, dyeing has the larger contributions in most of the impact categories with the exception of ozone depletion and marine eutrophication where scouring contributes most. 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Best Water resource depletion: Worst Best Freshwater ecotoxicity: Worst Best Marine eutrophication: Worst Best Freshwater eutrophication: Worst Best Acidification: Worst Best Human toxicity (NCE): Worst Best Human toxicity (CE): Worst Best Ozone depletion: Worst Best Climate change: Worst Sheep Farming Scouring Spinning Dyeing Master Thesis LCA of Two Textile Products: Wool and Cotton 70 5.2.2 Cotton yarns In Figure 19 is illustrated the results for the three selected case scenarios for the production of dyed cotton yarns and in Figure 20 the relative contribution of each life cycle stage in these results. Figure 19 - LCA results for the worst, average and best cases studied for cotton dyed yarn production. Results for the production of 1 kg of dyed yarn. Figure 20 - Relative contribution of each life cycle stage to the total impact in the cotton case scenarios: worst, average and best. Results for the production of 1 kg of dyed yarn. 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Worst Best 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Best Water resource depletion: Worst Best Freshwater ecotoxicity: Worst Best Marine eutrophication: Worst Best Freshwater eutrophication: Worst Best Acidification: Worst Best Human toxicity (NCE): Worst Best Human toxicity (CE): Worst Best Ozone depletion: Worst Best Climate change: Worst Cotton cultivation Spinning Dyeing & Bleaching Master Thesis LCA of Two Textile Products: Wool and Cotton 71 According to these results it is verified that significant potential improvements on the supply chain might be observed for the environmental impact categories of climate change, human toxicity (cancer effects) and acidification where reductions on its impacts might achieve values around 30%. These impact categories are strongly influenced by the spinning and dyeing & bleaching mills activities. For the overall results, cotton cultivation emerges as the main contributor (with the exception but with similar figures in human toxicity and acidification in the worst case scenario). Comparing spinning and dyeing activities it is verified that:  In the worst scenario spinning is the major contributor in climate change (but with similar figures as dyeing) and acidification while dyeing has the largest contributions in all the other categories. Spinning as significant contribution in the categories of ozone depletion and human toxicity (cancer effects)  In the best scenario dyeing is the major contributor in all the impact categories, spinning has significant contribution in climate change, ozone depletion, human toxicity (cancer effects) and acidification. Master Thesis LCA of Two Textile Products: Wool and Cotton 72 5.3 Comparative analysis of cotton and wool In order to compare dyed yarns made with wool and the ones made of cotton the case scenarios of each material are analysed for the minimum and maximum results (worst and best cases scenarios) obtained for each impact category. The relative contribution for the production of one kilogram each product is illustrated in Figure 21. Figure 21 - Relative impact of each product (wool and cotton) for worst and best case scenarios. Results for the production of 1 kg of dyed yarn. Observing the worst case scenario results, wool has the largest impacts in the overall results except in freshwater eutrophication (which figures are similar) and water resource depletion. On the other hand, looking into the best case results of each product, wool has the largest impacts in: climate change, ozone depletion, human toxicity and acidification; while cotton in water-related categories as: freshwater eutrophication, marine eutrophication, freshwater ecotoxicity and water resource depletion. Wool and cotton have approximate values in human toxicity (cancer effects) and marine eutrophication categories. Field emissions show up as the main contributors in most of the impact categories but, it has to be mentioned that wool processing has one more life cycle stage which also affects the final results as wool is a much more dirty fibre when compared with cotton. That way, washing, cleaning and other handling processes are more intensive and it reflects the results. On the other hand, cotton is a crop which is highly associated to the use of water, fertilizers and pesticides and that way, water and toxic related categories are the cause of its minor environmental performances. At this level of comparison, but remembering that different methods were applied, similar results to the one presented in Environmental Improvement Potential of Textiles (2006) for breakline contributions from life cycle stages of different textiles were analysed, are obtained 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Worst wool Best wool Worst cotton Best cotton Master Thesis LCA of Two Textile Products: Wool and Cotton 73 for the best case scenario. In that study wool is pointed as the major contributor in climate change and human toxicity (mainly due to the production of raw fiber), while cotton has the largest impacts in the categories of freshwater ecotoxicity (mainly due to the production of raw fiber). 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Master Thesis LCA of Two Textile Products: Wool and Cotton 85 Appendixes Master Thesis LCA of Two Textile Products: Wool and Cotton 87 Appendix A: ecoinvent datasets used for energy ELECTRICITY Table A. 1 – Electricity production and modelling correspondence in ecoinvent dataset. Source ecoinvent dataset Standard Grid Country mix in ecoinvent Electricity, low voltage, at grid Oil Electricity, oil, at power plant Gas Electricity, natural gas, at turbine, 10MW Coal Electricity, hard coal, at power plant Hydro Electricity, hydropower, at run-of-river power plant Solar Electricity, production mix photovoltaic, at plant Nuclear Electricity, nuclear, at power plant Renewables Electricity, pellets, allocation energy, at stirling cogen unit 3kwe, future Own Production Diesel Diesel, burned in diesel-electric generating set Hydro Electricity, hydropower, at run-of-river power plant HEAT Heat is produced inside the facilities or is provided by district heating sources. Regarding to the type of fuel used, boiler capacity and burner type utilized datasets was selected. As the heat fuels are entered in several units, the conversion factor is used to transform the unit given in the questionnaire into the unit (MJ) of the ecoinvent dataset. Inventory flow heat = Quantity of fuel * conversion factor Conversions factors as well as datasets selected per source of energy are presented in Table A. 2 Table A. 2 - Heat datasets from ecoinvent utilised for each supplier. Heat source Unit reported Conversion factor: unit to MJ ecoinvent dataset Suppliers District heat MJ - Wood chips, from forest, mixed, burned in furnace 1000kw/RER U S2 Diesel L 36.7 MJ/L Light fuel oil, burned in boiler 100kw, non-modulating/CH U D3 Natural gas m3 36.5 MJ/m3 Heat, natural gas, at boiler condensing modulating <100kw/RER U S1 and D2 Heat, natural gas, at industrial furnace >100kw/RER U S4, S5, S6 and D1 Master Thesis LCA of Two Textile Products: Wool and Cotton 89 Appendix B: ecoinvent datasets used for agriculture (sheep farming and cotton cultivation) MACHINERY Table B. 1 - Conversion factors for correspondence between fuel use in farming machinery and ecoinvent datasets. Machinery used for: ecoinvent dataset Conversion Factor L/FUa) FU in ecoinvent Pesticide application Application of plant protection products 2.0952381 ha Harvesting Combine harvesting 39.6547619 ha Fertilize application Fertilising, by broadcaster 6.29761905 ha Sowing Sowing 4.54761905 ha Cleaning Mowing, by rotary mower 4.086538462 ha Harrowing Tillage, harrowing, by spring tine harrow 5.28571429 ha Soil preparation Tillage, ploughing 31.0833333 ha Transports (tractor) Transport, tractor and trailer 0.04761905 tkm a) FU = functional unit Conversion to FU = Litres consumed (L) / Rate of diesel consumption of the dataset (L/FU) FEEDSTUFF Table B. 2 - ecoinvent dataset used to model the feedstuff production. Feedstuff ecoinvent dataset Silage Grass silage IP, at farm Maize grain Grain maize IP, at feed mill Hay Hay intensive IP, at farm FERTILIZERS Table B. 3 - ecoinvent dataset used to model the fertilizers production. Fertilizers ecoinvent dataset Ammonium nitrate, as N Ammonium nitrate, as N, at regional storehouse Ammonium nitrate phosphate, as P2O5 Ammonium nitrate phosphate, as N, at regional storehouse Compost Compost, at plant Monoammonium phosphate Monoammonium phosphate, as N, at regional storehouse Potassium chloride, as K2O Potassium chloride, as K2O, at regional storehouse Poultry manure Poultry manure, dried, at regional storehouse Single superphosphate Single superphosphate, as P2O5, at regional storehouse Master Thesis LCA of Two Textile Products: Wool and Cotton 96 WATER EMISSIONS Table D. 3 - Conversion factors and ecoinvent dataset for water emissions in Emmenneger (2013) Type of water emission / parameters Unit of measurement Conversion Factor WE ecoinvent (all in compartment "water, unspecified") Active chlorine, Cl (mg Cl/l) 1 Chlorine Adsorbable Organic Halogens, AOX, as Cl (mg Cl/l) 1 AOX, Adsorbable Organic Halogen as Cl Aldehydes, like CH2O (mg/l) 1 aldehydes, unspecified Ammonium, NH4-N (mg N/l) 1.285 Ammonium, ion Arsenic and ist compounds, As (mg/l) 1 Arsenic, ion Benzene-Toluene-Ethylbenzene-Xylene, BTEX (mg/l) 1 Proxy: Benzene Biochemical Oxygen Demand in 5 days, BOD5 (mg O2/l) 1 BOD5, Biological Oxygen Demand Cadmium and its compounds, Cd (mg/l) 1 Cadmium, ion Chemical Oxigen Demand, COD (mg O2/l) 1 COD, Chemical Oxygen Demand Chlorides, Cl- (mg Cl/l) 1 Chloride Chlorinated solvents (mg/l) 1 Chlorinated solvents, unspecified Chromium and its compounds, Cr (mg/l) 1 Chromium, ion Copper and its compounds, Cu (mg/l) 1 Copper, ion Dissolved solids (mg/l) 1 Dissolved solids Hydrogen sulfide, H2S (mg/l) 1 Hydrogen sulfide Iron and its compounds, Fe (mg/l) 1 Iron, ion Lead and its compounds, Pb (mg/l) 1 Lead Mercury and its compounds, Hg (mg/l) 1 Mercury Nickel and its compounds, Ni (mg/l) 1 Nickel, ion Nitrate, NO3-N (mg N/l) 4.43 Nitrate Nitrite, NO2-N (mg N/l) 3.29 Nitrite Organic nitrogen, N-org (mg N/l) 1 Nitrogen, organic bound Phosphate (mg/l) 1 Phosphate Polycylic Aromatic Hydrocarbon, PAH (mg/l) 1 PAH, polycyclic aromatic hydrocarbons Sulfates, SO4 (mg/l) 1 Sulfate Sulfide, S2- (mg/l) 1 Sulfide Sulfites, SO3 (mg/l) 1 Sulfite Suspended solids (mg/l) 1 Suspended solids, unspecified Total hydrocarbons (mg/l) 1 hydrocarbons, unspecified Total Organic Carbon, TOC (mg/l) 1 TOC, Total Organic Carbon Total phenols, Ph-OH (mg/l) 1 Phenol Total phosphorus, P (mg P/l) 1 Phosphorus Zinc and its compounds, Zn (mg/l) 1 Zinc, ion Note: All the emissions are modelled as emitted to the ecoinvent category water and sub-category unspecified Master Thesis LCA of Two Textile Products: Wool and Cotton 97 Appendix E: ecoinvent datasets used for chemicals, dyestuffs and auxiliaries Table E. 1 - ecoinvent dataset used to model the production of chemicals, dyestuffs and auxiliaries. Chemicals ecoinvent dataset Paraffin waxes Paraffin, at plant RER kg Lubricants Lubricating oil, at plant, rer Ester oils Chemicals organic, at plant/glo u Fatty acid triglycerides Chemicals organic, at plant/glo u Hydrogen peroxide (bleaching) Hydrogen peroxide, 50% in H2O, at plant/kg/RER Sodium hypochlorite (bleaching) Sodium hypochlorite, 15% in H2O, at plant/kg/RER Sodium chlorite (bleaching) Chlorine dioxide, at plant/kg/RER Optical brightener (brightening agent) Optical brighteners, in paper production, at plant/RER U Dyestuffs 50% Chemicals organic, at plant/GLO U + 50% Chemicals inorganic, at plant/GLO Sodium sulfate (dye auxiliarie) Sodium sulphate, powder, production mix, at plant Magnesium sulfate (stabilizer) Magnesium sulphate, at plant/kg/R Caustic Soda (washing) Sodium hydroxide, 50% in H2O, production mix, at plant/kg/RER Alcohol ethoxylates (surfactant, detergent or emulsifier) Ethoxylated alcohols, unspecified, at plant/RER U Sodium carbonate (builder) Sodium carbonate from ammonium chloride production, at plant/GLO Antistatic agent Chemicals organic, at plant/glo u Mono and diesters of phosphorus pentoxides (antistatic agents) Chemicals organic, at plant/GLO U Non-ionic surfactants Chemicals organic, at plant/GLO U Acetic acid Acetic acid, 98% in H2O, at plant/RER U Formic acid Formic acid, at plant Ammonium sulfate Ammonium sulphate, as N, at regional storehouse Salt Sodium chloride, powder, at plant Water-repellent 50% Chemicals organic, at plant/GLO U + 50% Chemicals inorganic, at plant/GLO Softener 50% Chemicals organic, at plant/GLO U + 50% Chemicals inorganic, at plant/GLO Master Thesis LCA of Two Textile Products: Wool and Cotton 99 Appendix F: ecoinvent datasets used for transports Table F. 1 - ecoinvent dataset utilized to model the transports Mode of transports ecoinvent dataset Sea Transport, freight, sea, transoceanic ship Road Transport, lorry 3.5-16t, fleet average Rail Transport, freight, rail Master Thesis LCA of Two Textile Products: Wool and Cotton 101 Appendix G: ecoinvent datasets used for solid waste Table G. 1 - ecoinvent dataset utilized to model the solid waste disposal Final disposal ecoinvent dataset Municipal landfill Disposal, municipal solid waste, 22.9% water, to sanitary landfill Municipal incinerator (with energy recovery) Disposal, municipal solid waste, 22.9% water, to municipal incineration Special treatment for hazardous waste Disposal, hazardous waste, 25% water, to hazardous waste incineration Master Thesis LCA of Two Textile Products: Wool and Cotton 103 Appendix H: Heavy metal content in fertilizers, wool and cotton HEAVY METALS IN WOOL For sheep pasture we only consider external import of heavy metal due to application of mineral fertilizers or organic fertilizer from other sources than sheep. Table H. 1 - Allocation factor for the single heavy metals Heavy Metals Allocation factor Sources from literature Wool % Meat % Wool Meat Cd 95 5 Kazemeini et al (2010) Average from literature 5 Patkowska et al. (2009) Smith et al. (2010) Cu 82 18. Nemecek et al. (2004) Zn 64 36. Pb 95 5 Ni - 100 Cr - 100. Hg 99 0.64% Table H. 2 - Heavy metal uptake of wool Heavy metals Concentration Sources from literature Wool kg/kg Meat kg/kg Wool Meat Cd 2.57E-07 6.99E-09 Average from literature5 Average from literature5 Cu 7.46E-06 9.00E-07 Nemecek et al. (2004) Average from literature5 Zn 7.51E-05 2.30E-05 Nemecek et al. (2004) Average from literature5 Pb 2.17E-06 6.50E-08 Nemecek et al. (2004) Average from literature5 Ni - 2.00E-08 Nemecek et al. (2004) Average from literature5 Cr - 4.00E-08 Nemecek et al. (2004) Average from literature5 Hg 1.45E-07 5.00E-10 Nemecek et al. (2004) Average from literature5 5 Average from values in Patkowska-Sokoła B, Dobrzański Z, Osman K, et al. (2009) The content of chosen chemical elements in wool of sheep of different origins and breeds. Arch Tierz 4:410–418 and in Smith K, Dagleish M, Abrahams P (2010) The intake of lead and associated metals by sheep grazing mining-contaminated floodplain pastures in mid-Wales, UK: II. Metal concentrations in blood and wool. Sci Total Environ 408:1035–42. doi: doi: 10.1016/j.scitotenv.2009.10.023 Master Thesis LCA of Two Textile Products: Wool and Cotton 104 HEAVY METALS IN FERTILIZERS Table H. 3 - Heavy metal content of synthetic fertilizers [33] Mineral fertilisers (%N/%P2O5/%K2O/%Mg) Cd mg/kg nutrient Cu mg/kg nutrient Zn mg/kg nutrient Pb mg/kg nutrient Ni mg/kg nutrient Cr mg/kg nutrient Urea (46/0/0) kg N 0.11 13.04 95.65 2.39 4.35 4.35 Calcium ammonium nitrate (20/0/0) kg N 0.25 60.00 155.00 5.50 90.00 10 Ammonium nitrate (27.5/0/0) kg N 0.18 25.45 181.82 6.91 47.27 14.55 Ammonium sulphate (21/0/0) kg N 0.24 19.05 142.86 5.24 8.57 9.52 Calcium ammonium nitrate (27/0/0) kg N 0.19 8.52 100.00 5.93 12.59 2.96 Magnesium ammonium nitrate (23/0/0/5) kg N 0.43 56.52 4.35 4.35 21.74 6.09 Generic mean N 0.21 22.25 121.43 5.37 17.17 7.81 Triple superphosphate (0/46/0) kg P2O5 113.04 97.83 650.00 7.61 95.65 567.39 Superphosphate (0/19/0) kg P2O5 52.63 121.05 852.63 578.95 105.26 342.11 Thomas meal (0/16/0) kg P2O5 1.56 250.00 425.00 75.00 125.00 1212.50 Hyperphosphate/raw phosphate (0/26/0) kg P2O5 50.00 115.38 915.38 23.85 76.92 611.54 Generic mean P 51.32 118.22 751.32 49.42 100.46 589.46 Potassium chloride (0/0/60) kg K2O 0.10 8.33 76.67 9.17 3.50 3.33 Potassium sulphate(0/26/50) kg K2O 0.10 4.00 64.00 6.60 1.60 4.00 Raw potassium (0/26/5) kg K2O 0.19 173.08 153.85 11.54 11.54 173.08 Lime kg CaO 0.12 4.00 8.00 3.60 12.20 314.00 Generic mean K 0.11 6.17 70.33 7.88 7.52 88.54 Table H. 4 - Heavy metal content of farmyard manure and organic fertilizers [33] Farmyard manure Cd mg/kg DM Cu mg/kg DM Zn mg/kg DM Pb mg/kg DM Ni mg/kg DM Cr mg/kg DM Hg mg/kg DM DM content % Cattle liquid slurry 0.178 37.1 162.2 3.77 4.3 3.9 0.4 9.0 Cattle slurry 0.16 19.1 123.3 2.92 3.1 2.1 0.6 7.5 Cattle staple manure 0.172 23.9 117.7 3.77 4.3 3.9 0.4 19.0 Cattle manure from loose housing 0.151 22.0 91.1 2.81 4.3 3.9 0.4 21.0 Pig liquid manure 0.21 115.3 746.5 1.76 8.6 6.7 0.8 5.0 Pig solid manure 0.21 115.3 746.5 1.76 8.6 6.7 0.8 27.0 Litter from broilers 0.292 43.8 349.2 2.92 40 10 0.2 65.0 Litter from belts from laying hens 0.2525 39.6 468.4 2.235 7.9 5.5 0.2 30.0 Litter from deep pits from laying hens 0.2525 39.6 468.4 2.235 7.9 5.5 0.2 45.0 Master Thesis LCA of Two Textile Products: Wool and Cotton 105 HEAVY METALS UPTAKE IN COTTON Table H. 5 - Heavy metal content of biomass [33] Heavy Metal Cd Cu Zn Pb Ni Cr Hg Crop kg/kg kg/kg kg/kg kg/kg kg/kg kg/kg kg/kg generic mean/cotton 8.90E-08 5.87E-06 2.85E-05 4.81E-07 9.26E-07 4.90E-07 3.56E-08 grass / hay 1.17E-07 7.74E-06 3.60E-05 1.08E-06 1.51E-06 9.81E-07 1.35E-07 grain maize 2.58E-08 2.15E-06 1.85E-05 2.58E-07 9.98E-07 2.75E-07 0.00E+00 silage maize 8.60E-08 4.30E-06 2.97E-05 1.38E-06 4.13E-07 6.02E-07 8.60E-09 wheat grains 8.50E-08 2.81E-06 1.79E-05 1.70E-07 1.70E-07 1.70E-07 8.50E-09 wheat straw 1.70E-07 2.13E-06 8.16E-06 5.10E-07 5.10E-07 5.95E-07 0.00E+00 barley grains 2.55E-08 3.66E-06 2.26E-05 1.70E-07 8.50E-08 8.50E-08 0.00E+00 barley straw 8.50E-08 4.08E-06 9.44E-06 5.10E-07 6.80E-07 1.02E-06 0.00E+00 rye straw 8.50E-08 2.72E-06 1.11E-05 3.40E-07 5.95E-07 4.25E-07 0.00E+00 potatoes 8.80E-09 1.42E-06 3.30E-06 1.21E-07 7.26E-08 1.25E-07 1.98E-08 rape seed 1.50E-06 3.10E-06 4.51E-05 4.94E-06 2.44E-06 4.70E-07 9.40E-08 fava beans 3.48E-08 5.22E-06 2.62E-05 7.57E-07 1.13E-06 6.00E-07 0.00E+00 soy bean 5.34E-08 1.34E-05 4.25E-05 7.12E-08 4.73E-06 4.63E-07 0.00E+00 protein peas 7.83E-08 8.70E-06 6.35E-05 1.39E-07 7.22E-07 2.78E-07 8.70E-09 sugar beet 9.20E-08 2.76E-06 8.37E-06 2.67E-07 2.48E-07 4.08E-07 2.19E-08 oil palm 5.30E-08 3.50E-06 1.70E-05 2.86E-07 5.51E-07 2.92E-07 2.12E-08 sugar cane 5.13E-10 1.28E-08 6.41E-08 2.57E-09 5.13E-09 2.57E-09 0.00E+00