Optimization of Textile Chains Ecodesign and Waste Minimization
COST Action 628: Working Group 2 “Dematerialization of the Textile Chain(s)”
Laboratory of Heat Transfer and Environmental Engineering Aristotle University of Thessaloniki, P.O. Box 483, 54124, Thessaloniki, Greece
Waste Minimization and the Process Industry
Waste minimization techniques in the framework of Ecodesign can lead to both long term and short term benefits: Reduce of liabilities
Promotion of a positive public image
Improvement of product quality Improvement of health and safety of employees Increase of operating efficiency Reduce of resources consumption and waste production Reduce waste treatment, disposal and production costs
Hierarchy of the waste management practices in terms of environmental protection
Total elimination of waste Prevention of waste production will be considered as the initial feasibility at design stage and may determine if the project proceeds
Avoidance, reduction or elimination of waste generally within the confines of the production units, through changes in industrial processes, procedures, products or input materials The use, re-use and recycling of waste in existing or other processes Destruction, detoxification, neutralization, etc. of waste to obtain less harmful substances Discharge of waste to air, water or land in properly controlled or safe ways such that compliance is achieved; secure land disposal may involve volume reduction, encapsulation, leaching of containment and monitoring techniques.
Waste minimization by source reduction Recycling Treatment
Waste Minimization and the Textiles Industry
The wet process part of the textile industry is characterized by large consumption of:
Process water Energy Chemicals Textile auxiliary agents Dyes … resulting in a large production of:
waste heat solid waste exhaust gases gas emissions
… which are generally released into the environment
Four types of waste are produced by textile wet processing:
1. Hard to treat wastes (dyes, metals, phenols, toxic organic compounds, phosphates)
2. Dispersible wastes (print paste, lint, waste from coating operations, waste solvents, batch dumps, unused finished mixes) 3. Hazardous wastes or toxics (metals, chlorinated solvents, non-degradable surfactants) 4. High volume wastes (waste water, alkaline wastes from preparation, bath dye wastes)
Wastewater Characteristics in the Textiles Industry
An Integral Approach to Waste Minimization
Proposed heuristic rules (1/2):
1. Elimination of waste materials at their source wherever possible. 2. Quick low cost reduction in waste generation can often be achieved through changing set points or tightening control variations of key variables. Modifications to single equipment items can also yield significant improvements with small capital expenditures. 3. Recycling of waste material within the process. If this is not possible, use off-site recycling.
Proposed heuristic rules (2/2):
4. If waste by-products are formed reversibly within a reaction process, they should be recycled to extension.
5. Use of the utility with the lowest practical temperature for all heating duties that require utilities. 6. Minimization of the total number of main equipment items in the process, especially in areas that handle toxic materials and of the total number of pipework connections to and from equipment items. 7. Due to practical purposes, continuous processes are preferred to others because pollution prevention is generally more costly in batch operations.
Waste Minimization Methodologies
1. Improved housekeeping
Good housekeeping in an industry implies that the management and employees of the company are diligent in ensuring that they comply with all environmental regulations, and in seeking ways in which the waste they generate and the resources they use are kept to a minimum. The following steps in housekeeping can lead to significant waste minimization: (a) an improvement in monitoring and operations of all phases of the production process, (b)schedule process in view of equipment cleaning (for example, formulation of light paints before dark paints will need no cleaning of vat before batches), (c) improved management of raw material and products inventory. Apart from that, reduction in raw material and product loss and provision of training to the employees can be effective means to improve housekeeping.
2. Changing process technology
This is an important technique for reducing waste volume and strength. Some examples are: (a) alteration in washing/cleaning procedure such as using counter current washing, recycling of used solvent and reducing the cleaning frequency, (b)employing new methods in production line cleaning, (c) changing waste transport method (waste from a poultry farm can be transported by mechanical means instead of using water), and (d)introducing biological degreasing in metal parts cleaning.
3. Changing product
Changing products which can serve the purpose of those which they substitute can bring waste minimization as in the cases of batteries (nonrechargeable to rechargeable), spray cans (volatile chemicals to water soluble formulations) and refrigerators (chlorofluoro-carbons to ammonia or environmentally safe materials).
4. Changing input material
1. In printing, water based inks can be substituted for chemical solvent based inks to bring waste minimization in solvents and to prevent air pollution due to the evaporation of solvents;
2. In textiles industries, the phosphate-containing chemicals can be reduced;
3. Water based film developing systems can be replaced with dry systems in electronic components; and 4. In painting of electrical light components, powder paints can be used instead of organic solvent based paints.
5. Recycling process chemicals and raw materials
Examples in recycling: (1) vapour recovery in printing, (2) dye recovery in the textile industry, (3) copper recovery in electroplating,
(4) paint and water recovery in the car painting industry,
(5) cutting oil recovery in machine workshops, (6) dye recovery in the jeans industry, and
(7) water recovery in the red meat abattoir industry.
6. Recovering by-product/waste
Some industries applying this technique are: pulp and paper, dairy, pig farms, and food processing industries such as pineapple, soup and desiccated coconut.
EcoDesign is a systematic way of incorporating environmental attributes and considerations into product, system and process design alongside performance, cost, legal, health and aesthetic requirements. All these requirements shape the design of the final product/process/systems/services, and the environmental considerations must fit into the design process alongside these other factors. There are three unique characteristics of EcoDesign: The entire life-cycle of a product, system, service and process is considered Point of application is early in the product realization process (although continuous improvement of all processes is recommended) Decisions are made using a set of values consistent with industrial ecology, integrative systems thinking or another framework.
The General Product Life Cycle
RAW MATERIALS EXTRACTION
T R A N S P O R T A T I O N
ENGINEERED AND SPECIALTY MATERIALS
PRODUCT MANUFACTURING RECYCLE PACKAGING FOR SHIPPING
RELEASES AND WASTES INTO THE ENVIRONMENT (SOIL, AIR, WATER, BIOSPHERE)
USE AND SERVICE
MATERIAL PROCESSED FOR REUSE IN ANOTHER PRODUCT SYSTEM
The Textile Chain
Primary production of natural and man made fibres
Production of yarns, fabrics and knittings
Auxiliary Water Energy
Wet processing (pretreatment, dyeing, printing and finishing)
Manufacture of ready - made clothing
considers the potential environmental impacts of a product, process, system or service throughout the entire life-cycle. These potential environmental impacts range from the release of toxic chemicals into the environment to consumption of nonrenewable resources and excessive energy use. Life stages of a product include all phases of the life cycle; from the extraction of resources needed to manufacture the product to its final disposal. In fact, designers design a product life – cycle not just a product. Knowledge of a product’s life – cycle will assist a company avoid environmental surprises and liabilities. If at all possible, the design team will seek to reduce these environmental impacts to the lowest level.
General Strategies for EcoDesign
Design for conservation resource Design distribution for efficient
Design for low impact materials Design for manufacturing Design for energy efficiency cleaner
Design for water efficiency
Design for consumption
Design for pollution prevention Design for durability Design for re-manufacture Design for disassembly Design for degradability
Design for re-use
Design for recycling Design for safe disposal
that can be used in the textile chains
Life Cycle Assessment
Application of LCA Methodology in the Textile Chains
Based on SETAC’s definition, LCA provides a framework, an approach, and methods for identifying and evaluating environmental burdens associated with the life cycles of materials, processes/operations, systems, and services, from “cradle-to-grave” or from “cradle-to-cradle”, which captures the recyclability of materials.
Stages in LCA of a technological activity; the wide arrows indicate the basic flow of information. At each stage, results are interpreted, thus providing the possibility of revising the environmental attributes of the activity being assessed.
Inventory Analysis • Raw materials and energy acquisition • Manufacture • Use • Waste management
Goal Definition and Scoping
Impact Assessment • Ecosystem Impairment • Health Impairment • Fatalities
Improvement Assessment • Materials and energy use reduction • Quantitative and qualitative measures of improvement
Life Cycle Assessment (LCA) methodology can be applied to processes, products, services, and systems in order to:
provide a clear view of the complete life cycle; assess the environmental effects of the complete or a part of the life cycle; pinpoint areas or processes of the life cycle that contribute the most to certain environmental effects;
assist in identifying and reducing environmental releases resulting from bad-performing processes/systems;
assist selecting the optimal process/system for the desired production/treatment with respect to the environmental aspect, and thus assist in reducing/minimizing wastes generation and resources consumption and depletion.
The flexibility of the LCA methodology allows for the adjustment of the approach and the results interpretation according to the factors that are related to and the characteristics of the textile chain, such as:
the surroundings and the local climate, and thus the environmental effects that are more important and hazardous for the local environment;
the processes/operations that are used;
the type (i.e. solid/effluents etc.) and composition (i.e. toxic/nontoxic) of the wastes;
existing textile industry improvements/upgrades; facilities that need
new/under design textile industry facilities, thus the selection of appropriate processes is a main concern.
Application of Exergy Analysis Methodology in the Textile Chain
Exergy Analysis methodology can be applied to single processes and/or complete systems (existing needed improvements/upgrades or new/under design) in order to:
assess exergy efficiencies of different manufacturing processes/operations of the textile industry and pinpoint areas where high exergy losses occur; optimize processes/operations/complete facilities, and thus, minimize or reduce high energy consumption, high wasted energy, environmental pollution and resource depletion. evaluate the utilization level of wastes treatment facilities; compare treatment processes/operations, thus assisting in the design of new facilities;