Textile processes pollute the environment and pose serious environmental and health hazards. Therefore, environmental standards have been established for textile and leather industry to control its pollution.
The main operations of textile processing industry are desizing, bleaching, dyeing, neutralizing, scouring, mercerizing, printing and finishing. These operations discharge high level toxic effluents that cause soil contamination, pollute air, ground water and surface water. Also, it can have adverse effects on the environment in general and human health. Moreover, textile industry is also main source of hazardous waste.
The environmental problems do not emerge only from the textile processes. For example non organic cotton cultivation uses more pesticides compared to any other crop in the world. This causes serious environmental impacts. Natural fibers require more processing steps than artificial fibers. Besides, certain dyes are known to be carcinogenic.
The utmost point of environmental concern is discharge of large amount of waste water loaded with chemicals. Other important issues are energy consumption, air pollution, solid wastes and odors. The main pollutants present in textile waste effluent are toxic heavy metals, bio-chemical oxygen demand (BOD), chemical oxygen demand (COD), residual chlorine, dissolved solids, color, sludge, used oil, dyes and non biodegradable organics.
With such complex textile processes and the growing concern of their impact on the environment, it was essential to establish harmonized and globally recognized standards for the textile industries. Global Organic textile standards, (GOTS) was introduced which has universal recognition and has more than 3000 certified textile processing, manufacturing and trading people in more than 60 countries. It has adopted standards for processing textile goods using fibres which are environmentally, socially and economically sustainable.
Apart from GOTS, other international organizations have established various environmental standards and measures to reduce pollution from the textile industry. Some of them are EKO sustainable textile standard, Organic textile standard (Italy), Organic Fiber Standards (USA), Standards for Processing of Organic Textile Products (Argentina). The standards set by these organizations ensure reduction of textile pollution and promote use of organic fibers and eco-friendly textile production methods.
There are numerous environmental standards established to reduce the environmental impacts of textile industry. Some general and important ones are- use of natural and azo free dyes, use of organic fibres, minimizing carbon footprint, reduce water and energy usage, etc. The textile industry releases large amount of volatile chemicals and pollutants mainly from coating, finishing, dyeing and printing processes.
The standards to reduce textile pollution focus on avoiding the use or discharge of alkyllphenol-ethoxylates and minimum use of organic solvents. Also, avoiding non-degradable surfactants and spinning oils in washing and scouring processes. Pad batch-dyeing is recommended as it is an effective method. It saves 80% of energy requirement and 90% of water consumption. It also reduces usage of dye and salt.
Exhaust dyeing is advised for knitted items. Further, use of jet dyers is favorable compared to winch dyers. One must avoid using benzidine based azo dyes, chlorine based dyes and dyes having cadmium and other heavy metals. Also, these standards advocate avoiding toxic dye carriers containing chlorine and finishing agents. Peroxide based bleach must be used instead of sulfur and chlorine based bleach. The standards recommend that VOC (volatile organic compound) emissions must be less than 1kg carbon per metric ton of fabric.
Introduction of new technology has also played an important role is reducing textile pollution. The new reactive dye, Avitera-SE, is recommended for cotton dyeing. Along with the latest technology, it will significantly reduce the water consumption for cotton dyeing compared to the traditional methods. Further, innovation called 'Gentle Power Bleach' reduces energy and water consumption by 30-40% while bleaching. Also, this technique cuts down the carbon emission.
The leather industry consists of refining raw skin into leather products. This whole process requires number of complex chemical and mechanical processes. Among all these processes, tanning is the most important process. The leather industry too generates high level of pollution by using chemicals such as biocides, surfactants and wastewater discharge.
Several measures to reduce to environmental impact of tanneries have been developed for the leather industry. Some of the important ones are: It is necessary to train the staff for occupational health and safety of workers. Tanneries must develop environmental management system. The workers must be provided masks to avoid inhaling toxic gases. There must be proper drainage system to prevent the formation of hydrogen sulfide in the tannery.
The solid waste from the tanneries must not be used for poultry food. Furthermore, there are techniques available to reuse the chrome, discharged in the effluent such as direct recycling of chrome, recycling of chrome after precipitation, etc. Wastewater from the tanneries should be treated at two levels. The first level treatment includes mechanical screening, pH leveling, flocculation, solidification and sedimentation.
The second level treatment requires biological process to remove organic matter from the waste water. Treatment technologies like activated sludge, percolating filter, aerated lagoon, facultative lagoon etc. are available. Activated sludge treatment is a proven and effective technology to treat tannery wastewater and is used all over the world.
Research has shown that numerous chemicals released by the leather industry have harmful effects on the environment. Hence, it is necessary to make efforts to reuse and recycle chemical components. Therefore, further environmental recommendations have been suggested to make leather production environment friendly. Training programs of modern techniques must be provided to all the workers.
Safety materials like protective shields, acid resistant gloves, aprons, masks must be made available to each worker. Informative tips for safety, health and environment must be displayed in the tanneries. To conserve water, orderly washing instead of continuous washing method should be used. This will not only save water but also reduce the amount of wastewater treatment. Eco-friendly chemicals like enzymatic products must be used replacing sulfides and surfactants.
With the help of new dyeing technologies, major textile processing countries like China, India and Bangladesh will reduce their water consumption by over 50%. In the path of adopting environmental measures, major apparel and footwear brands and retailers have set a goal of achieving zero discharge of hazardous chemicals (ZDHC) by 2020. This plan has set new standards of environmental performance in textile and leather industry.