Textile Manufacturing Process, Pollution and

Pollution Control

Contents

Topic Name Page No

Introduction 01

Materials Raw of Textile Process 01

Textile Manufacturing Process

02-04

Water Consumption Pattern of Textile Industry 05

Textile Wastewater or Effluent 06

Physical Characteristics 06-07

Chemical Characteristics 08-09

Classification of Textile Waste water in Textile Industry

10

Effluent Characteristics of Textile Industry Processes 11

Water Pollution and Textile Effluent 12

Treatment of Wastewater 13

Conclusion 13

References 14

Textile Manufacturing Process, Pollution and Pollution Control

1

Textile Manufacturing Process, Pollution and

Pollution Control

Introduction

The industrial development is essential for socio-economic existence of a nation. The

environment with its biotic and abiotic components provides basic resources that support

production consumption by population and assimilates the residues produced during these

activities. The major environmental issues related to industrial development are over exploitation

of natural resources and environmental pollution. Therefore, the protection of environment and

natural resources is a must for the proper development of a country. Industrial wastes are

comprised of different types of solid waste, liquid waste, hazardous waste and gaseous waste

.The characteristics of industrial waste are different from municipal and commercial wastes.

They contain a huge amount of inorganic, organic and organometallic substances that discharge

from the individual sources and mix into Human Environment. The liquid form of the industrial

waste is termed effluent. Environmental pollution due to different types of industries is one of

the vital problem presently facing the India and all over the world. Textile industries are major

sources of Environmental pollution. As the textile industries consume large quantities of water

and generates waste water in proportionate order.

Materials Raw of Textile Process

∆ Yarn

∆ Fabric

∆ Dye stuff

∆ Chemical and auxiliaries

Textile Manufacturing Process, Pollution and Pollution Control

2

Textile Manufacturing Process

Textile manufacturing or production is a very complex process. The range of textile

manufacturing is so long. It starts from fiber to finished products.

Spinning

↓

Weaving

↓

Dyeing +Printing +Finishing

↓

Garments Manufacturing

Spinning

Blowroom

Carding

Drawing

Combing

Drawing

Roving Manufacturing

Ring Spinning

Weaving

Yarn from spinning section

Doubling and Twisting

Winding

Creeling

Warping

Sizing

Winding on weavers beam

Weaving

Dyeing

Inspection of grey cloth

Stitching

Cropping

Brushing

Singeing

Desizing

Textile Manufacturing Process, Pollution and Pollution Control

3

Scouring

Bleaching

Souring

Washing

Drying

Mercerizing

Dyeing

After treatment

Finishing

Inspection

Packing

Baling

Printing Inspection of grey cloth

Stitching

Cropping

Brushing

Singeing

Desizing

Scouring

Bleaching

Souring

Washing

Drying

Mercerizing

Dyeing

After treatment

Finishing

Inspection

Packing

Baling

Garment Manufacturing

Design / Sketch

Pattern Design

Sample Making

Production Pattern

Grading

Marker Making

Spreading

Cutting

Sorting/Bundling

Sewing/Assembling

Textile Manufacturing Process, Pollution and Pollution Control

4

Inspection

Pressing/ Finishing

Final Inspection

Packing

Despatch

Figure: Cotton Textile Goods

Textile Manufacturing Process, Pollution and Pollution Control

5

Water Consumption Pattern of Textile Industry

Major contribution of the raw effluent are from the sizing & desizing, scouring, dyeing &

bleaching, mercerizing section of the industry. Apart from these main unit operations, a

substantial quantity of effluent is generated from the humidification section. Concentration of

pollutants and quantity of effluent from these sections may vary depending upon the scale of

production, chemicals used and technologies adopted. Following table may give an idea for raw

water requirement in similar type of industries. Water loss is approximately 20% mainly from

the humidification section.

Figure: Water Consumption in wet processing of Textile

Sl. No. Product Quantity of water required

1 Denim 30-35 litres per meter of cloth.

2 Knitting fabric * 90 litres per Kg of fabrics produced.

3 Shirting section 110 litres per meter.

4 Trousers 80 Litres per meter of cloth produced.

Table: Quantity of water required

Textile Manufacturing Process, Pollution and Pollution Control

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Textile Wastewater or Effluent

Textile wastewater includes a large variety of dyes and chemical additions that make the environmental

challenge for textile industry not only as liquid waste but also in its chemical composition. Main pollution

in textile wastewater comes from dyeing and finishing processes. These processes require the input of a

wide range of chemicals and dyestuffs, which generally are organic compounds of complex structure.

Water is used as the principal medium to apply dyes and various chemicals for finishes. Because all of

them are not contained in the final product, became waste and caused disposal problems. Major pollutants

in textile wastewaters are high suspended solids, chemical oxygen demand, heat, color, acidity, and other

soluble substances. Substances which need to be removed from textile wastewater are mainly COD,

BOD, nitrogen, heavy metals and dyestuffs.

Physical Characteristics

The principal physical characteristics of wastewater are its

∆ Solids content- The total solids in a wastewater consist of the insoluble or suspended

solids and the soluble compounds dissolved in water. The suspended solids content is

found by drying and weighing the residue removed by the filtering of the sample. When

this residue is ignited the volatile solids are burned off. Volatile solids are presumed to be

organic matter, although some organic matter will not burn and some inorganic salts

break down at high temperatures.

∆ Color- Color is a qualitative characteristic that can be used to assess the general

condition of wastewater. Wastewater that is light brown in color is less than 6 h old,

while a light-to- medium grey color is characteristic of wastewaters that have undergone

some degree of decomposition or that have been in the collection system for some time.

∆ Odor-The determination of odor has become increasingly important, as the general

public has become more concerned with the proper operation of wastewater treatment

facilities. The odor of fresh wastewater is usually not offensive, but a variety of odorous

compounds are released when wastewater is decomposed biologically under anaerobic

conditions

∆ Temperature-The temperature of wastewater is commonly higher than that of the water

supply because warm municipal water has been added. The measurement of temperature

is important because most wastewater treatment schemes include biological processes

that are temperature dependent.

Textile Manufacturing Process, Pollution and Pollution Control

7

.

Table: DOE Standards for Industrial Discharge

Figure: This figure shows the physical characteristics of industrial wastewater

Textile Manufacturing Process, Pollution and Pollution Control

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Chemical Characteristics

The principal chemical characteristics of wastewater are its

∆ Inorganic chemicals-The principal chemical tests include free ammonia, organic

nitrogen, nitrites, nitrates, organic phosphorus and inorganic phosphorus. All living

organisms require varying amounts of some trace elements, such as iron, copper, zinc and

cobalt, for proper growth.

∆ Organic chemicals-Laboratory methods commonly used today to measure gross

amounts of organic matter in wastewater include (1) biochemical oxygen demand (BOD),

(2) chemical oxygen demand (COD) and (3) total organic carbon (TOC).

∆ Volatile Organic Carbons (VOC)-Volatile organic compounds (VOC) such as benzene,

toluene, xylenes, dichloromethane, trichloroethane and trichloroethylene, are common

soil pollutants in industrialized and commercialized areas. One of the more common

sources of these contaminants is leaking underground storage tanks.

∆ Heavy metals- It can be seen that of all of the heavy metals chromium is the most widely

used and discharged to the environment from different sources. Mercury generates a great

deal of concern as a heavy-metal pollutant. Mercury is found as a trace component of

many minerals, with continental rocks containing an average of around 80 ppb, or

slightly less, of this element. Lead from leaded gasoline used to be a major source of

atmospheric and terrestrial lead, much of which eventually enters natural water systems.

∆ Inorganic pollutants and species-Hydrogen sulphide, H2S, is a product of the anaerobic

decay of .organic matter containing sulphur. Cyanide ion, CN-, is probably the most

important of the various inorganic species in wastewater.

∆ Organic pollutants and species- Soaps, detergents and associated chemicals are

potential sources of organic pollutants. Others, such as refractory (degradation-resistant)

organics (organ chlorides, nitro compounds etc.) and salts and heavy metals, are not

efficiently removed.

Textile Manufacturing Process, Pollution and Pollution Control

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Property Standard Cotton Synthetic Wool

pH 5.5 – 9.0 8-12 7-9 3-10

BOD, mg/l, 5

days

30-350 150-750 150-200 5000 – 8000

COD, mg/l, day 250 200-2400 400-650 10,000 – 20,000

TDS, mg/l 2100 2100-7700 1060-1080 10,000 –13,000

Table: Comparison with different parameters and Pattarns

Figure: This figure shows the chemical characteristics of industrial wastewater

Textile Manufacturing Process, Pollution and Pollution Control

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Classification of Textile Waste water in Textile Industry

Textile waste is broadly classified into four categories, each of having characteristics that

demand different pollution prevention and treatment approaches. Such categories are discussed

in the following sections:

Hard to Treat Wastes:

This category of waste includes those that are persistent, resist treatment, or interfere with

the operation of waste treatment facilities. Non-biodegradable organic or inorganic

materials are the chief sources of wastes, which contain color, metals, phenols, certain

surfactants, toxic organic compounds, pesticides and phosphates. The chief sources are:

o -Color & metal → dyeing operation

o -Phosphates → preparatory processes and dyeing

o -Non-biodegradable organic materials → surfactants

Hazardous or Toxic Wastes:

These wastes are a subgroup of hard to treat wastes. But, owing to their substantial

impact on the environment, they are treated as a separate class. In textiles, hazardous or

toxic wastes include metals, chlorinated solvents, non-biodegradable or volatile organic

materials. Some of these materials often are used for non-process applications such as

machine cleaning.

High Volume Wastes:

Large volume of wastes is sometimes a problem for the textile processing units. These

wastes sometimes can be reduced by recycle or reuse as well as by process and

equipment modification.

Most common large volume wastes include:

-High volume of waste water

-Wash water from preparation and continuous dyeing processes and

alkaline wastes from preparatory processes

-Batch dye waste containing large amounts of salt, acid or alkali.

Dispersible Wastes:

The following operations in textile industry generate highly dispersible waste:

-Waste stream from continuous operation

-Print paste (printing screen, squeeze and drum cleaning)

-Lint (preparatory, dyeing and washing operations)

-Foam from coating operations

-Solvents from machine cleaning

-Still bottoms from solvent recovery (dry cleaning operation)

-Batch dumps of unused processing (finishing mixes)

Textile Manufacturing Process, Pollution and Pollution Control

11

Effluent Characteristics of Textile Industry Processes

Effluents from the textile industry commonly contains high concentrations of organic and

inorganic chemicals and are characterized by high Chemical Oxygen Demand (COD), Biological

Oxygen Demand (BOD), Total Dissolved Solids (TDS), pH, Total Suspended Solids (TSS)

values and low Dissolved Oxygen (DO) value as well as strong color.

Process Effluent Composition Pollutant Nature

Sizing Starch, waxes, Carboxymethyl

Cellulose (CMC), Polyvinyl

Alcohol (PVA), wetting agents.

High in BOD, COD

Desizing Starch, CMC, PVA, fats,

waxes, pectins

High in BOD, COD, SS,

dissolved solids (DS)

Bleaching Sodium Hypochlorite, Cl2,

NaOH, H2O2, acids,

Surfactants, NaSiO3, Sodium

Phosphate, short cotton fibre

High alkalinity, high SS

Mercerizing Sodium Hydroxide, cotton wax High pH, low BOD, high DS

Dyeing Dyestuffs Urea, reducing

agents, oxidizing agents,

Acetic acid, detergents,

strongly colored, high BOD, DS,

low SS, heavy

Printing Pastes, urea, starches, gums,

oils, binders, acids,

Thickeners, cross-linkers,

reducing agents, alkali

Highly colored, high

BOD Oily, appearance, SS,

slightly alkaline

Source: Bruggen et al, 2001 and EPA, 1998

Textile Manufacturing Process, Pollution and Pollution Control

12

Water Pollution and Textile Effluent

Textile wastewater includes a large variety of dyes and chemical additions that make the

environmental challenge for textile industry not only as liquid waste but also in its chemical

composition. Main pollution in textile wastewater comes from dyeing and finishing processes.

These processes require the input of a wide range of chemicals and dyestuffs, which generally

are organic compounds of complex structure. Water is used as the principal medium to apply

dyes and various chemicals for finishes. Because all of them are not contained in the final

product, became waste and caused disposal problems. Major pollutants in textile wastewaters are

high suspended solids, chemical oxygen demand, heat, color, acidity, and other soluble

substances. Substances which need to be removed from textile wastewater are mainly COD,

BOD, nitrogen, heavy metals and dyestuffs.

Industry Water

Pollution

Pollution

Product

Ranking

Agriculture Moderate 1.08 3

Textile *

Big 3.35 1

Transport Small 0.02 6

Construction Small 0.14 5

Paper Very big 0.67 4

Leather Extreme 1.88 2

Sugar Extreme 1.72 2

Table: Water pollution source and their ranking in Bangladesh

Textile Manufacturing Process, Pollution and Pollution Control

13

Treatment of Wastewater

After every effort that may be made to reduce waste strength and volume, there still remains the

problem of desposing the final remains of polluted waste into any water stream, thus the waste

may be treated in various methods either singly or in combination and the best combination of

methods differs from plant to plant. The various typs of treatment are as follows-

Segregation

Lagooning and Storage

Screening

Mechnecal Filtration

Pre-aeration and Post-aeration

Neutralization

Chemical Precipitation

Chemical Oxidation

Biological Oxidation

Conclusion

Characterization of textile process effluent streams is very important to develop strategies for

water treatment and reuse. To optimize treatment and reuse possibilities, textile industry waste

streams should be in principle considered separately. When the characteristics of the separate

streams are known, it can be decided which streams may be combined to improve treatability and

increase reuse options.As discussed textile sector is putting enormous impact on Bangladesh

economy yet this industry is currently facing several challenges. Out of various activities in

textile industry, chemical processing contributes about 70% of pollution. Waste stream generated

in this industry is essentially based on water-based effluent generated in the various activities of

wet processing of textiles. It is well known that wet processing mills consume large volume of

water for various processes such as sizing, desizing, and scouring, bleaching, mercerization,

dyeing, printing, finishing and ultimately washing. In fact, in a practical estimate, it has been

found that 45% material in preparatory processing, 33% in dyeing and 22% are re-processed in

finishing. But where is the real problem? The fact is that the effluent in textile generated in

different steps is well beyond the standard and thus it is highly polluted and dangerous.

Textile Manufacturing Process, Pollution and Pollution Control

14

References

C.M. Noorjahan., Physico-chemical Characterization of Untreated Textile Effluent and

its Effects on Biochemical Constituents of Fresh Water Fish, Tilapia Mossambica, ISRJ, I

(V), 1-11 (2011).

N. L. Nemerow, Industrial Water Pollution Origins, Characteristics and Treatment,

Addison Wesley, Reading, Massachusetts, 738 (1978).

Environmental Protection Authority (EPA, 1998). Environmental Guidelines for the

Textile dyeing and Finishing Industry, State Government of Victoria, Melbourne,

Victoria, Australia.

Guha, A. K. and Hoque, M. I. 2009. “Characterization of Textile waste water of Different

Areas of Bangladesh” Bangladesh Textile Today, 2 (3): 16-20.

Jamaluddin, A. M. and Nizamuddin, M. 2012.“Physicochemical Assessment of Textile

Effluents in Chittagong Region of Bangladesh and Their Possible Effects on

Environment”, International Journal of Research in Chemistry and Environment; 2(3):

220-230.

Savin I., Butnaru R., (2009), Research on the Decrease of the Ecological Impact on

Wastewater in the Textile Industry – Studies on the General Features of Wastewater in

the Textile Industry, Bulletin of the Polytechnic Institute of Iaşi, in press.

Bisschops, I. and Spanjers, H. (2003) Literature review on textile wastewater

characterisation. Environ. Technol. vol. 24, pp. 1399-1411

Nemerow, N.L. (1978) Industrial Water Pollution: Origins, Characteristics and

Treatment. Addison-Wesley, Reading, Massachusetts, pp 738.