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Cotton Life Cycle Inventory and Assessment: Cradle to Grave

To meet the challenge of increasing environmental accountability, Cotton Incorporated in 2009 began participation in the Cotton Foundation's Life Cycle Inventory & Life Cycle Assessment of Cotton Fiber & Fabric, a complete examination of cotton product life cycles.

Generally, a Life Cycle Inventory (LCI) is a collection of data sets that measures inputs and outputs such as energy, water, and raw material requirements; air and waterborne emissions; solid wastes; and other environmental releases that occur throughout the life cycle of a product, process, or activity.

Sustainability Booklet Available for Distribution

Cotton Incorporated’s publication, A World of Ideas: Technologies for Sustainable Cotton Textile Manufacturing, provides a summary of ideas and estimated investments to help improve your cotton business while reducing the environmental footprint of the world’s number one consumer fiber. Strategies are identified for the reduction of water, energy, and chemicals (WEC) throughout textile processing, including the areas of process; chemicals and dyes; equipment; systems, control, and management; and wastewater treatment.

Visit the Cotton Incorporated "Cotton Today" Web site, to view or download a PDF version of the booklet, A World of Ideas.

A Life Cycle Assessment (LCA) is a complete examination of the potential environmental impact and resource utilization of a product, from the raw materials used in manufacturing to disposal at the end of life. The LCA is based largely on information contained in Life Cycle Inventories.

As it relates to cotton, the primary purpose of the LCI, which includes years 2005-2010, is to provide a comprehensive inventory of current data for global cotton fiber production and textile manufacturing based on modern industry practices. The LCA used LCI data to determine the potential impact through all cotton product life cycle phases. The environmental categories (and examples) included Acidification Potential (acid rain), Eutrophication Potential (nutrient loading to stream), Global Warming Potential (green house gas emitted), Ozone Depletion Potential (ozone hole over polar ice caps), Photochemical Ozone Creation Potential (smog), Primary Energy Demand (electricity and fuel needed), and Water Consumption (irrigation).

The new LCI data and subsequent LCA will help the cotton industry better understand all aspects of the environmental impact of cotton textiles, enabling all segments to focus research and resources on reducing future impacts. Cotton supply chain decision makers will be able to evaluate more accurately the environmental impact of products specific to their businesses.

In the fabric production segment, the LCI data represent global averages for knits and wovens by mills in China, India, Turkey, and Latin America in 2009, which accounted for 66 percent of knits and 51 percent of wovens processed worldwide. The data include bale opening, yarn preparation, spinning, knitting or weaving, wet preparation, dyeing, and finishing. The data elements also included raw material inputs and outputs; energy inputs by source; dye/chemical input, output, and emissions; and solid waste amounts and their ultimate waste disposal (recycled, sold, or sent to landfill). The functional unit used in measuring environmental impact is 1,000 kilograms of knit or woven fabric.

Among the 16 textile mills included in the LCI are an equal representation of those dedicated to spinning, knitting, weaving, or dyeing and finishing operations, as well as mills that conduct all of those functions. A previous study along with the technical service experiences of Cotton Incorporated staff helped identify mills that accurately represent the overall textile production practices in the countries of interest.

Regional differences for similar processes are taken into consideration in the LCI data. For example, the electrical energy required to operate a spinning frame may be the same regardless of the country where the equipment is in operation; however, the environmental impact of the power plant generating the electricity and the efficiency with which that energy is delivered to the mill can vary significantly between countries.

The LCI data was used to conduct LCAs that tracked cotton garments through a three-phase life cycle: 1) fiber production (agricultural processes); 2) fabric production (textile processes); and 3) consumer use (wearing and washing to the end of life). With the prevalence of cotton in the apparel market, the environmental impact of textile products was narrowed to focus on the life cycles of a knit golf shirt and a pair of woven cotton trousers. During the use phase of the assessment, the assigned functional weight was 1,000 kilograms of garments, which is equivalent to 2,780 knit shirts or 1,764 woven pairs of trousers.

The LCA was supplemented with consumer behavior data from the Cotton Incorporated Lifestyle Monitor™ consumer survey, an ongoing Internet survey of U.S. consumers who are representative of the U.S. Census based on education, income, ethnicity, marital status, and geography. Consumers surveyed were 60 percent female, 40 percent male, and 13-70 years old. Approximately 1,000 survey participants were asked questions about their use and laundering practices for knit shirts and woven pants.

Similar to other LCAs, the LCA of the life cycle of cotton garments supports the conclusion that the consumer has a significant environmental impact during the use phase, which is due to laundering habits over the life span of cotton products.

Another significant phase is textile manufacturing, which contributes to environmental impact during the spinning of yarn and the conditioning, processing, and heating of water in fabric preparation and dyeing steps.

Michele Wallace, Associate Director, Product Integrity at Cotton Incorporated, noted that energy consumption, water use, and wastewater discharge are primary areas of environmental impact in the textile manufacturing process. Of those, immediate attention will be directed toward energy. "Energy usage, especially, is an area of opportunity for focus on improved sustainability," she said. Most of the LCA data, which was based on ring spinning, indicate the possibility of reduced environmental impact and increased efficiency with both rotor spinning and air jet spinning.

 

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