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Recovery from textile industry waste E-mail

Code No: TMS121 Price: Rs1850/- Category: Storage

 

Introduction

Recycling and reuse of textile wastes has assumed importance in the recent past in our country. With the rise in the living standards, the demand for textiles and clothing is expected to grow. Like any other industry this industry also generates all categories of industrial wastes namely liquids, solids and gases. Various useful materials can be recovered from these wastes by utilization of new processes. The wastage of raw materials can be reduced by improving manufacturing process at each stage, thereby savings in the major inputs. During the process certain kind of wastes such as solid wastes can be recovered by adopting new technologies, whereby these wastes can be converted into useful materials for other applications.

Textile industry is one of the largest industries, which consumes energy in the form of heat. New technologies are required to recover some percentage of loss of energy.

Wastes utilization in the textile industry is gaining vital importance in the Indian textile industry as international legislations are also to come into force in our country. The country is looking for export market, and hence, certain standards laid down by the European countries have to be adopted. It is in this contest this Techno- Market Survey on “Recovery from Textile Industry Wastes” has been prepared.

Scope and Coverage

The scope of the study shall be as per the guidelines issued by TIFAC. The salient features of the scope are:

1. Relationship and the importance the specific topic to the broad area to which it belongs (Brief).

2. The current status of the technology in the world and in the country. Market (domestic and export) sizes and their potentials (Use existing information / reports to the maximum extent possible).

3. Assessment of the technology, resources parameters such as energy, raw materials, infrastructure, manpower etc. to arrive at the preferred technology options available to the country.

4. Short term and long term economic aspects of preferred options along with their feasibilities.

5. Impact of the preferred option(s) and its spinoffs

6. Recommendations

i) For implementations of preferred technology option(s) identifying critical inputs such as raw material, capital goods and human resources required and their availability, investments required to commercialize, and benefits/returns expected.
ii) For R&D / Technology development identify the requirement of inputs and expected benefits.

7. Action Plan for implementation of recommendations alongwith identification of:

a) List of available technologies for Indian industry and
b) The agencies/groups/individuals for implementation.

8. Expected impact of recommendations, if implemented

Importance of the Topic

The importance of the textile industry to the national development is evident by the growth and the size of the industry in terms of its production capacity, and in terms of the value of various inputs and outputs.

The products in cotton textiles, from registered manufacturing sector in India, have yielded an output value of Rs. 9,714 crore in 1981-82. This has risen to Rs. 29,746 crores in 199091, which reflects the degree of expansion. The cotton textile industry including ginning units, spinning units and weaving & processing, produce wastes, which have intrinsic value of almost Rs. 100 million per year. This relates to only one type of solid waste of textile industry. It is estimated that the total solid wastes, including those of man-made fibres, and rags which are collected I huge quantities, when recycled would amount to Rs. 300 million per year. The other wastes in the textile industries, for example chemicals and dyes have been estimated between Rs. 300 to 350 million per year. There are about 270 registered composite mills in our country.

The energy consumption in cotton spinning and weaving is about 6-7 percent of the value of output. In dyeing and bleaching of woolen textiles it is roughly 29.9 percent and in printing and bleaching of silk textiles it is 13 percent of the value of output. These figures relate to 1989-90. The heat energy that goes waste is about 25-30 percent of the total energy consumption.

In the context of environment protection and current disposal of the textile wastes into the environment it becomes essential to recover useful products from the wastes for economic reasons. The reutilization of waste water can present very important savings, namely in reduction of water, energy and chemical consumption. The recycling of waste water is effected in process baths and rinsing waters, before water is taken for treatment for removal of remaining chemicals and other effluents generated. Steam condensate and cooling water are easily recoverable as they are clean. Their thermal energy can very quickly pay back the investment.

The recovery of chemicals such as caustic soda from mercerization is by heating the caustic wash liquor. The concentrate when evaporated 90% of the caustic soda can be recovered.

The EVAC vacuum suction system in the textile dyeing process recovers hot alkaline hydrogen peroxide, additives and finishing chemicals. The finished quality of the cloth surface improves. The technology also helps in recovering wastes generated and reuse of chemicals. Another advantage in this process is the recovery of wet steam which is sent ot the steam trap where the condensate is collected. This technology

a) Increases the productivity
b) Saves in chemical waster and fuel.
c) Reduces pollution load and cost of waste water and water treatment.

The recovery of PVA AND CMC from synthetic fabric designing bath is much profitable and can be done either by ultra filtration or coagulation. Advanced oxidation process for recycle and reuse of dye bath by Excolour technology developed by Centexbel.

Basically there are two categories of solid wastes:

a) Manufacturing waste, which is the waste from the various manufacturing processes.
b) Recovered and reclaimed wastes, which is waste collected after use and then reprocessed.

The fabric waste from carding, combing, drawing and spinning are called soft waste. Wastes produced after spinning and twisting and in the process for weaving and knitting is called hard waste. Finishing waste are also called locks, which are from the finishing process of the fabric. Reclaimed wastes are mostly in the form of rags and old discarded clothing. There are wool wastes and non-wool wastes.

The technology developed by M/s Laroche is the most scientifically developed technology for textile wastes recycling. The technology for recycling can be applied to –

a) Man-made fibre (filament and staple)
b) Spinning
c) Weaving & knitting
d) Garments and other textile products
e) Non-woven wastes and old garments

These wastes are properly recycled by this technology which can be used to manufacture an extremely wide range of high quality articles.

The weighing metering technology is used for fibre to fibre multi component blending. The bales are kept on the input conveyor belt and small bunches of fibres are fed into the weighing pans. Load cells measures and record each weighing separately. The machines give perfect pre-opening and pre-blending.

These lines can accommodate productions between 50 and 2500 kg/h of waste generated. The fibre length improves by 25% and the power consumption is reduced by 20%. These waste can become the source of raw material for the integrated industries [1].

The silk industry is one of the oldest industries in our country, using very old methods and employing very large work force. There are wastes generated during different stages of silk processing, such as during winding, throwing, spinning and weaving. The extraction of oil from pupae wastes is carried by hexane oil extraction method, since dried pupae contains 28.4% of oil which is largely used as poultry feed [2], and fish feed. Some Korean make machines have been developed for extraction of this oil.

Polyester wastes can be recycled in many different ways depending on type of wastes and its ultimate use. As the environmental pollution on awareness is increasing even in developing countries, the ability of recycle polyester will make it a material of choice in the times to come.

The cost of energy in textile industry forms a significant share of the total cost in the textile industry. In order to recover energy it is necessary to concentrate on operations that involve the heating of water, dying on baking of textiles. Heat recovery from exhaust gases and from effluents is discussed in the study. In European countries new technologies have been developed which have been proved economical.

The technologies developed by various research institutions in our country have been implemented in various textile mills which has resulted in pollution control and biogas generation.

Methodology

The methodology adopted in the present study has the following features:

1. The technologies developed in the Indian scenario to recover and reuse the waste from the textile industries. A questionnaire (Annexure – I) was prepared and was sent to various textile industries (Annexure – III). A detailed literature survey as well as field survey o these technologies was collected and collated, and a primary survey report was prepared (Annexure –II).

2. An extensive work study on foreign technologies especially in the countries on textile waste recoveries have been given its due recognition.

3. The study has been further carried out to identify the textile wastes that need to be treated which include the soil waste, effluents, energy, dyes & chemical.

4. The computer results give at a glance the conclusive effects of the relevant studies.

Assessment

The assessment of some of the technologies which were available to us for studies have been mentioned in the study and their long term economic aspects have been discussed.

Limitations

The limitations encountered during the study carried out were:-

1. Non- availability of different options of technologies, though large number of literature study and interaction with people from textile industry revealed only what is given in the study.

2. A prudent approach to identify specific requirements of textile industry in the matter of use of advanced methods for recovery of textile wastes would have been a detailed survey of at leas major industries in India. This however, has not been possible for want of time and other constraints within the scope of the present assignment.

3. Financial constraints have been another constraint to visit industrial set-ups in the country to collect first hand information.

However, all departments, pertaining to textile processing, right from spinning to the recovery and reuse of various solid textile wastes, after they have been worn by the people and ten discarded, have been discussed. The study highlights the scope of recovery in the textile industry and textiles as such. The recovered waste have tremendous end use, either in the process of manufacturing of primary products or secondary products or the products which have no relevance to the textile industry at all.

Major Observations

Waste recovery from the textile industry and textiles on the whole, has not been given its due attention in our country. Of late the R&D institution such as Central Cotton Research Institutes and textile research institutes in the country have taken up the assignment but then it is only form the environmental, pollution and recovery of chemicals, point of view.

The following agencies have done pioneering work in out country. Amongst them:

1. Indian Institute of Technology,
Powai, Bombay

2. Northern India Textile Research Association,
Sec.23, Raj Nagar, Ghaziabad, U.P.

3. Department of Chemical Engineering,
Hauz Khas, IIT, New Delhi

4. Sir Padampant Research Centre, A division of
J.K. Synthetics Limited, Kota, Rajasthan

5. Karnataka State Sericulture Development Institute,
Thalashattapura, Bangalore – 560 062

The areas in which these institutions have done some pioneering work, are:-

1. Recovery of dyes and chemicals by combinations of certain processes in te dying process.

2. Contributions have also been made in the silk industry whereby the wastes generated in the silk industry during rearing of soil and reeling operations have been identified. The oil has been extracted from pupae collected in the silk industry.

3. Willow dust collection and generation of bio gas is an other significant achievement by different research institutions, which have been adopted by the textile mills in our country.

4. Heat recovery is a other area which requires more in-depth study. The recovery of heat energy requires serious attention. Pioneering technologies have been developed in other countries such as France, U K. and Germany. Some of the methods developed in those countries have been briefly described in this work.

5. Other areas are utilization of soil wastes, which is generated in the textile industry. This is a complex field. Textiles include cotton, polyester based mixed with cotton, dyed with different chemicals, fabrics. It can also encompass recovery from rags, such as carpets. The various by products that can be produced from these wastes are quite interesting and technologies for their effective utilization much be adopted. Use of these wastes ha also found its application in the irrigation and soil conservation [3].

6. Some of the news technologies developed for the recovery of polyester fibre wastes generated in the synthetic fibre processing has been also mentioned. Polyester wastes also find its use in producing Hotmelt- Adhesives.

Recommendations

1. The following technologies have been recommended for the recovery of specific wastes in the textile industry.

Area
Technology
Waste Recovery
Dyes ad Chemicals Ultra-filtration technology

Ex-colour technology (Advanced oxidation technology)

EVAC-Vacuum technology

Physicochemical technology

(Zero discharge) by TDS control

PVA (polyvinyl alcohol) in sizing cotton fibres

Colour


Chemicals


Recovery of chemical from effluents

Soil Wastes Developed by M/s Laroche-Invotex, France Cotton wastes
Hard wastes
Old rags
Polyester Wastes Siko-Plast Maschinen fabrick, Germany Polyester fibres, lumps
Waste Heat Recovery Platular waste heat recovery

ETSU technology

Technologies available in India

Waste heat recovery from gases

Recovery of waste heat from effluents containing soil wastes.

Waste heat recovery from different processes in a dying house.

Willow Wastes BTRA-CTRL technologies Biogas generation from willow wastes.

 

2. R&D institutions and the Research Centres of IIT’s of Bombay, Delhi and Kanpur have done commendable work in the areas of recovery of dyes, chemicals and waste heat. However, another most important area, which requires a deeper understanding of technologies and for their adaptation by Indian industry, is recycling and reuse of soil wastes. Since the production of textile mills is increasing and with that the volume of soil waste are also increasing, it is strongly recommended to create a work force. It is worthwhile to mention that in 1987-88, 340,000 (kg-lakhs) of shoddy wool/wool wastes/wool rags/synthetic rags were imported valued at Rs. 3080 lakhs, by Indian woollen industry in woolen spinning, worsted spinning and carpet spinning [4]. The consumption was more than the imported quantity, which shows that this large quantity of waste requirements has been recycle. Efficient technologies should be evaluated and implemented.

Action Plan

The textile industry so large in size generates different kinds of wastes. The economic viability of suitable technologies is difficult to recommend, unless and until the textile mills prepare an assessment report for adopting a particular technology. It is strongly recommended that a plan to be drawn ascertain and categorize the various textile industrial outputs in the country and the wastes generated. The plan should be for organized as well as unorganized sector. The set up of each one of these industries must be analyzed and conclusions must be drawn to categorize waste generated in each industry.

There are large scale, medium scale and small scale industries. Each one of these generate wastes during the process of manufacturing. The Ministry of textiles and the research institutions must be evolved. It is not possible to meet the textile producing units to ascertain the systems adopted by them.

The research institutions should also study the technology given in this report and give their assessment for implementation and adaptation of these technologies.