3

Bombay Textile Research Association, Bombay.

INTRODUCTION

h e to rapid industrialization all over the world, mere

conservation of utilities like energy and water does not solve the

various problems forcing constraints on such activities- The

textile mills not only add to air pollution by ejecting chimney

gases into atmosphere, but also caume considerable water pollution

by discharging their effluents into varioua receiving bodies. For

this reason, eone htandards were specified firstly for water,

under the 'Water (Prevention and Control of Pollution) Act,' 1974,

and subsequently for Air under " A i r (Prevention and Control of

Pollution) Act 1981"- Both theae acts were supplemented by

"Environmental Protection Act" in the year 1986, It hae now been

decided by the Government that beginning thia year ie, (19931,

every industry requiring coneent under the abovementioned Acts,

should erubmit an "Environment Statement (Audit) Report" to the

concerned State Pollution Boarder, The induertry would benefit, if

it takes a broad outlook and considers Environmental Audit as a

tool for managing its resource@ efficiently, with minimum

3.1

generation of waertes. This paper gives data/information which

would be useful for the mills not only in preparation of

Enviro-ental Statement but also in broad understanding of the

various issues involved- , -

\ *

RNVIRO”TAL-+OLLUTION IN THE =TILE INDUSTRY

Environmental pollution caueJed by the textile indu~ltry can be

clasaified into two types (1) Water pollution and (2) Air

pol lut ion .)

Water pollution in the textile mills is mainly caused due to the

various waste streams emanating from the wet processing operatione,

like desiainp, scouring, bleaching, mercerizing, dyeing and

printing. The boiler blow down and the effluent discharged from

the water treatment plant also contribute to the pollution.

A i r pollution is caused by chimney gases of the boilers on

combustion of fuels like coal, oil and natural gas, etc. Fumee

emitted from various eguipments open to the atmosphere and

suspended particulate matter in the apinning department of the

mills also add to the air pollution.

WATER P~LLUTION

Manufacturing Processes or Process Stages

Production of cloth in textile mille shows a w i d e variation in

terme of quantity, quality and type of fabrics. Synthetic fibre

has become an integral part of the textile industry and is being

-

3.2

used to manufacture purely synthetic fabric or is mixed with

cotton to manufacture blended fabrios in mills throughout the

country -

The sequence of dry operations in a composite mill start from

carding to weaving for preparation of grey cloth. No waste water

is generated except in the caee of sizing operation where a small

amount of waste water i t 3 generated from washing of kettles and

spillages on the floor. The remaining unit operations in the

chemical proceesing, viz., desizing, scouring, bleaching,

mercerizing, dyeing, printing and finishing are wet processes. A

variety of chemicals, viz., enzymes, acids, alkalies,

hypochlorite, peroxide, dye8 are a180 used. The waste water

generated from these chemical processes contains appreciable

quantities of unused chemhmls alongwith other organic matter like

fats, waxes, pectin, solid fragments and etarch. In addition,

some goods are water-proofed with aluminium acetate or formate

mixed with gelatin and a diapersed wax, which adds to the

waste water.

procese

W a t e r Cbntnmption

Water i t3 used in textile mills mainly for three purposes,

proceesing, cooling and boiler. The overall consumption of water

or the quantity of water required in various sections of a procerss

house depends on the quantity of cloth proceseed and the number of

sequences adopted for rinsing, washing, etc. Water usage

increases when fine and superfine varieties of cloth are

3.3

manufactured. Water coneumption is also related to r J . w

availability of water to the mill. Water requirement varies from

120 to 230 l/kg of cloth proceeeed with an average value of 170

l/kg- Water Consumption Norms for various proceesea are given in

Appendix-1.

l v b l l ~ m e and Characterdstdcs of Waste Water

Volume

The quantity of waste water derived from kiering, bleaching,

dyeing and printing is large as compared to the other unit

operations in a textile mill. The waste water volume, like water

usage, varies considerably from mill to mill. The combined waste

water volume lies in the range of 90 to 1801 with an average of

134 l/kg of cloth processed. The waste water discharged amounts

to 70 to 80 percent of water consumed with an average value of 74

percent, The quantity of waate water diecharged in a few

composite textile mills is given in Appendix-2.

The waste water flow rate varies due to the batchwise operations.

The flow rate of waste water in textile mille is provided in

Appendix-3- It indicates that the ratio of peak flow to the

average flow ranges from 1.49 to 3.39.

Characteristics of Waste Water

For Cotton Textiles

The details about the proceaswise effluents discharged for cotton

processing are given in the following :

3 .4

Slasher Waste Water

Slashing (sizing) is the first grocese during weaving in which

liquid treatment is involved, Although slashing compounds used

most often are natural starches, others, such as PVA, reeine,

alkali soluble cellulose derivatives, gelatin glue, etc., are also

used. One of these, sodium CMC. is mostly used in sizing of

wlyester blends. Other chemicals such as lubricants, softeners,

emulaif iers, humectants preservatives (ZnC12, phenol, etc.

penetrants, antifoam agents and fillers are often added to impart ~

additional properties to fabric. Liquid wastes from slashing

mainly arise from cleaning of slasher boxes, rolls and make up

kettles. Some spillage also occurs but the volume is very low.

Slashing operations normally contribute only 5% BOD and 4.5% T.S.

to the total plant waste load.

&sizing Waste Water

The,operation of desizing remove^ sizing compound that are applied

to the threads in the slashing operation. Most common deeiaing

operations are acid degsizing with dilute H2SO4 at room temperature

for a period of 4 to 12 hr and enzyme desizing with vegetable or

animal enzyme8 at a temperature of 130 to 180°F and pH of 6 to 7.7

for a period of 4 to 8 hr. After the size has been solubilized,

the fabric is rinsed clean. No decomposition is required for

desizing of CMC and PVA as they are directly eoluble in water.

The waste from desizing operations contribute the maximum BDD of

all and approximately 45% from the cotton finishing operations.

3.5

Compared to the pollution load arising from desizing of eynthetic

size (CMC, PVA) the waste from starch desizing has maximum MI3

load and total solids.

&owing W - t e Water

In scouring, the natural impurities (wax, pectins, alcohols, e t c . )

as well as process impurities ( s i z e , dirt, o i l and greaae, etc.)

are removed from the fabric by hot alkaline detergents or soap

solutions. Scouring is accomplished by two methode, kier boiling

or open width scouring depending on the characteristics of the

fabric.

Caustic soda (NaOH) (1 to 8% of cloth weight) and soda ash

(Na2C03) (1 to 3%) are used in most scouring operations. Sodium

silicate is generally used in small doses (0.25 to 1%). Pine oil

soap to remove wax and fatty alcohol sulphate8 to aid in melting

are .also sometimes used in scouring. The waste is dark brown in

colour and exerts high BOD ie 30-35% of the total BOD load. The

contribution of grease and oil is approximately 67% of the total.

This is due to natural wax, oil and dirt present in cotton along

with other organic niaterials removed from cloth by alkali

digestion.

Merserizing Waste Water

The process enables increase in textile strength. surface lustre.

abrasion reBistance, reduction in potenthl, Eshrinkage and

___

3.6

increased affinity for dyestuffs.

by saturating:

cisustic sod8

mercerization.

alkaline, high

in BOD, around

the fabric with cold

Mercerization is accomplished

NaOH (15 to 30%). Generally,

is recovered and reused for ecouring or

Mercerizing wastes are low in volume, highly

low in inorganic solids and cauatic alkalinity and

100 m&l.

Bleaching Waste Water

Bleaching but

sodium hypochlorite , sodium chlorite and hydrogen peroxide are

more commonly used. The rinses from sodium hypochlorite bleaching

are usually neutral in pH, vary in BOD and contain considerable

of cotton cloth may be done with oxidizing apents.

amount of free residual chlorine. In the final rinse, H2SOq ac'id

or sodium bisulphite is used as an antichlor for the removal of

residual chlorine. In the case of sodium chlorite bleaching,

acetic acid is used as an antichlor.

H202 is generally used for continuous bleaching and ie employed

for processing the majority of cotton and cotton blended fabrics.

NaOH is used in the process for the removal of WBXBB and soaps.

Use of peroxide will reduce the pollution load leaving no residual

solids. The bleaching process contributes 5 to 10% BOD to the

total pollutional load.

of the

Process Waste Water

process contributes about 10-20% of the total volume. BOD

waste water is generally low but ita contribution m y be as

-

3.7

high as 3756 of the total BOD load in some mills. Waste waters may

contain quantities of chromium if aniline or sulphur dyeing

methods are used. Appendix-4 presents a list of cotton dyes and

chemicals used in the dye baths.

Finishing Waste Water

Finishing covers the treatment of a fabric to give it a desired

etc. Starch, dextrin, wax, tallow, oil, clay, talc and other

weighting compounds are typical finishing compounds. In recent

years resins, cellulosic solutions, lacquers, sulphonated

compounds and quaternary ammonium salts have been used. Other

finishing processes, such as levelling off (hot detergsnte) to

produce a uniform appearance, softening (hot eoap) to produce a

soft feel and rust stain removal (oxalic acid and sodium acid

fluoride) to improve colour are also eometimes used.

Finishing waters are low in BOD and waete water volume is also

low.

Combined Waste Water Characteristicg

The combined waste water from a composite cotton textile mill

constitutes different waste waters as stated above. It contain6

large varieties of organic and inorganic chemicale such as dyes,

pigments, waxes, starch, dextrin, gum, ~ioeip, detergents, alkalies

eulphates, chlorides and heavy metal iona like chromium- The

waste water contains highly dissolved inorganic solids. It is

higiilr alkaline and has a high BOD and suspended solids. It is

3.8

also deficient in nitrogen and phosphorous and hence nutrient like

DAP (Diammoniurn phoglphate) has to be added for carrying out

biological treatment. Appendix-5 givee the BOD value8 of some of

the cotton textile wet procesees.

For Synthetic Textiles

Synthetic fibre8 are esaentially composed of pure chemical

compounds and hence have no natural impurities. Because of this,

only light scouring and bleaching is required to prepare the cloth

for dyeing. Fibres can be grouped into two claeehes, those which

are manufactured from cellulose like rayon or cellulo~e acetate

I

and those.produced synthetically from organic materials such as

nylon, polyester and acrylics. Processing of fibres and cloth is

readily done on the conventional machinery used for cotton-

Pollution from treatment of these fibres originate6 from the

varioue scouring and dyeing chemical8 used to process them. The

characteristics of the waste water from synthetic textile milla

are presented in Appendix-6. Despite the u8e of a higher

concentration of dyes and chemical8 in the synthetic cloth

processing, the waste water from such process houses is low in BOD

and solids concentration providing scope for inexpensive waate

water treatment and recycle syetemrs. .(,

The Average Pollutional Loads observed in the wet processing of

eynthetic fibre-fabrics is given in Appendix-7.

3.9

, /'

In-Plant Control

Source reduction should be every mill's first line of defence

against pollution, with resultant improvements in quality and

safety. It is usually accomplished by the following different

techniques.

Conservation of Water

Comparison of actual water consumption data with target figures

indicates the magnitude of savings that may be achieved simply by

using less water and without changing machines or processing

'I procedures in any way. Saving of this nature are likely to be

m o r e available in washing operations than in chemical baths.

Typical water conservation measures are given below :

0 Reduced water consumption in washing machines by reducing the

rate of flow of water and/or throttle the water supply in

such washing machines.

0 Counter-current flow of washing in mercerizing both for

washing with and without neutralizing on the range and for

soaping.

0 Collection and reuse of eteam condensate in boiler feed

water - 0 Reuse of condensate from caustic soda recovery plant in

washing of mercerized goods. ~

0 In mercerizing operation, use of recuperator, high

temperature for washing and increasing the force of washing

would lead to reduced water consumption.

3.10

0

0

0

0

0

0

0

0

The

In jigger dyeing, static washes in place of running water

washes ehould be employed-

A s far as possible, resort to.padding methode of dyein

thereby obviating the neceasity of pretreatments.

oling water flow, then segregate/recover.

Turn off cooling water on unused machines.

Use automatic shut off valves/interlocke on hoses.

Use flow restriction in hoses.

Good housekeeping (reduces clean-up water).

Avoid exceasive water for equipment cleaning.

other water conservation mea~urcs will be covered in detail in

1 ,

another paper.

i Prtnzem WiNcatfontz

Alteration of processes and material flow procedures is another

way of reducing the water consumption and also to eliminate

unnecesaary wastes. Continuous operations require a Bmaller

space, use less water and procees chemicals. Combination of

separate processes like scouring and dyeing in the finishing of

synthetic fibres and the desizing and scouring of cotton fibres is

advantageous. Another method of procese modification ie to

substitute standing baths and rinses for running ones, thus

conserving water and concentrating the waste load in the bottom of

the process unit, Inetead of discharging the effluent, it can be

stored in a storage tank and reused in the make-up of the next

similar bath. In addition to this modification. heat exchangere

3.11

can be used to transfer the high temperature of s o m e effluents t o

incoming process water thereby not only reducing water heating

costs but also minimizing the possibility of thermal pollution.

SubstJtution of chemicals

The BOD load of a mill can be reduced by substituting low BOD

procese chemicals for those having high BOD values. Three

classical examples of process chemical substitution exist in the

textile industry viz. the substitution of CMC and PVA (synthetic

eize) for starch (50% BOD) in the eizing of cloth, use of mineral

acids (0% BOD) for acetic acid (33-62% BOD) and low BOD

biodegradable synthetic detergents for soaps (140% EPoD) ie

biodegradable synthetic detergent of the linear alkylate

sulphonate type, commonly known ats LAS. These compounda are

converted to new biological cell tissues by aerobic oxidation and

can be removed from the effluent by settling tanke. The

additional BOD exerted by using biodegradable detergents ie only

5% in excess to the BOD exerted by the non-biodegradable synthetic

detergents.

Recovery of &y-produets

The effluent load can be considerably reduced if some of the

polluting chemicals present in the effluent can be recovered e . g .

recovery of caustic from the mercerization waste. Of the various

dyes used in the dyeing operation, vat and indigo dyes are

consumed to a large extent. About 65-8556 of vat dye ie picked by

the fabric and the rest goes as waste, The waste liquor

3.12

.containing this dye can be segregated from the other dye house

effluents for the recovery of the dyes.

Housekeeping is another important issue. Disorderly chemical mix

areas, drug room8 and colour kitchene where spilled chemical8 and

colour are waahed down the drains with water, hosee are major

contributore to pollution from many mills. Often, hosee are left

perpetually running in these areae, resulting in water WaOtetsl to

the tune of thousands of gallons every day. Simple teChniQUs8

relating to manual handling euch as using separate dipper6 and

buckets for each chemical to reduce chemical 1080 through rinsing

give major reductions. Screen cleaners, drum washers, tanker

trucks washing can a180 be major problem areas. Many times

syillagee, leakages of raw materials into the main drain can

contribute substantially to the pollution load of the effluente,

e-g: leakages in caustic recovery evaporator sycltem are eometimee

so major, as to increase the caustic alkalinity of the composite

effluents considerably.

Sbmgation

Segregation of certain waate water stream for separate treatment

‘is often advantageous to reduce the concentration of a sptscific

pollutant before combinina with the rest of the streamsp e=g=,

kier wastes cauee problem8 in the biological treatment because of

its high temperature,pH and alkalinity. It is extremely difficult

to acclimatize the micro-organitsma employed in biological

3.13

treatment for reducing the BOD load of the waste, even after

mixing with domestic sewage.

A common method is to hold kier discharge after every batch into a

holding tank and discharge a small proportion of it at fixed

intervals into the composite waste during treatment so as to be

harmless to the micro-organisms. Such wastee can be segrelpated

from the other wastes and can be held in tanks from where it can

be continuously discharged in such a small amount, a8 not to cauet

any problems in the subsequent treatment processes. Similarly,

dye liquors can be separately treated by coagulants and oxidizing

agents .

EXfluent Treatment

When all means of reduction of quality and quantity of effluent

are adopted then the effluent can be treated for either disposal

or reuee,

For disposal, effluent should meet the different standards

depending upon its discharge into :

0 Inland surface waters (IS:2490)

0 Municipal sewers (IS3333071

0 Irrigation (IS:3308)

0 Marine coastal area (IS:7968)

The standards for discharge of effluents are given in Appendix-8

whereas the terms involved are defined in Appendix-9.

3.14

Several methods are available for the treatment of waste water

from the textile mille. The choioe of the method8 will differ

from plant to plant and the method or combination of methods beet

suited for a particular waste ie governsd by the following

factors :

0 Quantity of effluent to be diecharged

0 Processes employed in the mills

0 Type of receiving bodies 8.g. public m~werm or river or

irrigation land, etc.

R.eatment k t h o d s

Conventional treatment of textile effluents are a8 follow0 :

0 Egualisation

0 Neutralisation

0 Proportioning

0 Colour removal and

0 Reduction of organic matter

Due to constant fluctuation8 in quality and Quantity, textile

effluents need to be treated in two stagers.

The first stage covers e~ualieation, neutralisation, proportioning

end colour removal. The aecond atage will include BODICOD

reduction by biological treatment. Since biological treatment ie

senaitive, it is eserential to equaliee effluent and make it

uniform before it is admitted for treatment wherever water ie to

be ueed for procees; it is eeeential to FOIIIOVB) dirsolved solids

3.15

which are not treated in the firat two stages. Hence tertiary

treatment is used.

First Stage Treatment (Primary Treatment)

This will comprise

- Equalisation tank

Equalisation of the waste water is an eseential first step in

treatment of textile wastes because of variation in flow and

characteristics of different streams. The treatment processee,

operate well at the conditions of constant flow and

characteristics of the flow. Normally, the tank is designed to

hold the effluent f o r a period of eight hours.

- Neutralisation

This is done to provide a pH range conducive for the metabolic

activities of the micro-organisms. Lime or hydrochloric acid is

generally used for neutralisation.

- Chemical Coagulation

Chemical coagulation is one of the effective methods for the

removal of suspended colloidal impurities. It also removes colour

and BOD from the textile wastes. The chemicals used for

coagulation include lime, alum, and iron sslts. A typical

chemical coagulation process consists of chemical dosing, mixing,

flocculation and solids separation.. In the mixing, the coagulants

are dispersed thoroughly in the waste water. In flocculation, the

particle size increases due to the agglomeration of the colloidal

material and settles faster. Sedimentation or air flotation

3.16

process is used to separate the solids from the waste water. At

this stage, the sludge produced needs tu be removed and dried out

either on aand beds or mechanically by vacuum filtration or

pressure filtration.

Second Stage (Secondary Treatment)

Textile wastes contain inadequate amounts of nitrogen and

phosphorus apart from carbon required for biological treatment.

$he waste water after proper pretreatment can be effectively

subjected to biological treatment fo r the removal of organic

matters contributing to CUD and BOD. Both trickling filter and

activated sludge process can be employed for the treatment.

Presently, activated eludge process is widely used , fo r the

biolugical treatment of low and medium etrength waetes. Thie

system has an advantage of flexibility and if operated properly

can give a BOD reduction upto 95%. In this systems the micro-

organisms in the waste water are kept in suepension for the

requiri3d period and allowed to settle to separate the solids

formed due to biological activity. The activated sludge process

consists of an aeration tank equipped with surface aerators. The

aerated liquid is then transferred to a clarifier f o r settlement

of sludge. The sludge is recycled back to aeration tank by means

of pumpf;, whereas clear liquid from clarifier is dirposed.

Aeration tank capacity can vary from 12 to 48 hr depending upon

strength of waste, whereas clarifiers hold settled waste for two

hr. Though activated sludge is a compact, reliable and Consistent

3.17

process,

provided for.

Third Stage (Tertiary Treatment)

The first and second stages have the objective to reduce pH.

euspended solids, colour, BOD and COD. However, these steps do

not alter the dissolved mineral constituente. If treated waete is

it requires high p o w e r which needs to be considered and

to be used for process, it is necessary to give separate treatment

in the degree desired. For process r e u ~ e of textile effluent, it

is necessary to use demineraliaation proceee in combination with

reverse osmosis plant. Precaution should be taken to reduce all

suspended solid8 and BOD/COD before effluent is subjected to the

tertiary treatment,

AIR POLIUTIOW

Textile Industry by the nature of ita operation8 is not a major

sourqe of air pollution. Apart from boiler emissions, other

emissions from textile processing units are (1) oil and acid,

mists, (2) solvent vapours, (3) dust and lint and ( 4 ) odours.

Sources of Air Pollution in a Textile Mi11

D Oil mists are produced when textile materials containing

oils, plasticizers and other materials that can volatilize or

be thermally degraded into volatile substances are subjected

to heat. The most common source

industry is the tenter frame- ,

of oil mists in the textile

3.18

Acid mists are produced during the carbonizing of wool and

during some types of epray dyeing and acetic acid miet

dyeing -

0 Organic solvent vapoure are releaaed during and after all

solvent processing operations. The most common use of

solvent processing is the use of chlorinated hydrocarbons for

dry cleaning.

0 Dust and lint fly are produced in large quantity by the

processing of natural fibres and synthetic polyeetsr fibre8

during spinning and by napping and carpet shearing.

0 Odours are often associated with oil mifate or solvent

vapours. The most common source i e the aqueous polyester

dyeing and processes eubsequent to it. Resin finiehing also

produces odours, chiefly of formaldehyde. Other eources of

odour are sulphur dyeing on cotton and cotton blends;

reducing or stripping dyes with hydroeulphite, bonding,

laminating, back coating and bleaching with chlorine dioxide.

0 Chimney gasers of boilers on combustion of fuels like coal,

oil, natural gas, etc. emit pollutants which are mainly the

particulate matter and mlphur dioxide. Thi0 can be reduced

by the use of LSHS oil instead of furnace o i l due to its low

sulphur content,

3.19

Instrum&nts Required for Air Quality Mnitoring

0 Stack-Monitoring Kit

0 High Volume Sampler

0 Hand-held Anemometer

0 Wind-vane Meter

o Whirling Hygrometer

0 Temperature Meter

BASIC AIR POWION CONTROL E Q U I ~ S

0 Incineration

- Open Flame

- Direct Fume

- Catalytic Oxidation u

0 Dry Collectors

- Cyclone Separator

- Filters

Bag House

Mist Eliminator

High Velocity Fibre Mat

- Electrostatic Precipitator

- Absorption

0 Scrubbers

- Packed Tower

- Plate Column

3-20

- Spray Tower

- Inertial Impaction

- Fluidized Bed

- Orifice

- Venturi

- Water Jet

- Mechanical

- Fibre Bed

- Reinstate

- Ionizing Wet

FEASIBLE ABATEMENT TECHNIQUES FOR THl$ AIR POLLUTANTS

Po 1 lutant --------- 0 Oil Mists

AbatemenWTechnique ------------------- Process modification, incineration, high energy scrubbers or use of eleotrostatic precipitators

Electrostatic precipitatore generally lead lined, high efficiency mist elimi- nators of acid reaistant materials

o Solvent Vapours Solvent recovery by adeorption onto activased carbon

0 Odours Process or chemical substitution and housekeeping improvement, Dilution, Masking or Modification, Scrubbing, Dry adsorption, Incineration

0 Lint and Coarser Low energy scrubbers iike Cyclone Duet Scrubbers and eprqy towere, filters of

fibre glasrs or steel me&.

Fine Dust Electrostatic precipitators, high effi- ciency air filters, venturi scrubbers or'direct fume incinerators

3.21

AbatementlTechnique -------------------

0 Particulates from Gravitational settling chambers, centri- Stack Gases fuga1 separators (cyclonee) wet

scrubbers, filters, Electrostatic precipitatore, Ultrasonic amlomeratore

Venturi scrubber with limeetone slurry as an absorbing media, packed tower

Combustion modifications like modification of burner, design, etc. lime stone injection

AHBIENT AIR QUALITY STANDARDS

{Jnder Section 16(2)(h) .r.f Air (Prevention and Control of

Pollution) Act, 1981 and the Environment (Protection) Act 1986,

the following air quality ctandarda were adopted.

’ On the basis of land use and other factors, various areas of state

may .be classified tnto three categories by concerned State

Pollution Control Bosrd viz.,

o Industrial and Mixed Use Areas

o Residential and Rural Areas

CJ Sensitive Areas

According to procedures specified by the Central Board, the

concentrations for the following pollutants shall be 95% of the

time, within the limits prescribed below :

3-22

A. Indus tr ia l and Mixed Use

B, Residential and Rural

5QQ 120

200 80

5000 120

2000 80

C. Sensitive 100 30 1000 30

3-23

Appendix-1

WATER CONGUHPTION N O M

Water Conmmmption at Different Stages

1.

2.

3.

4.

5.

6.

7.

8 . ’

9.

10.

11 .. 12.

13.

Desize Saturator

Caustic/Peroxide Saturator in J-Box Range

Kier

Washing Machines

Rope Washing

Tensitrol Type

Open Width Scouring/Peroxide Range

Mercerising Machines (with counter-current washing)

Jigger Scouring/Bleaching

Heavy Duty Jumbo Jigger (preparation of PC blend)

Ordinary Jiggers

Open Width Dyeing Soaper (five compartments)

Continuous Dyeing Range

Yarn Dyeing Plant (all operations)

Beam Dyeing (including washing subsequent to dyeing)

Conventional

Modified

2.0

l,O/Saturator

10.0

15.0

15.Onange

20.0

30 Each Operat ion

30

2s to 35

15.0

25.0

l O O . O / k g yarn

25.0

15.0

14. Jet Dyeing (inclqding washing SUb88QU6mt to dyeing)

Conventional 20.0

Rapid 15-0

15 - Neutral 2.0

16. Water Mangle 2.0

17 - Starch Padding Mangle 2.0

18 - Preshrinking Range 1.0 (with water-reuse)

19. Carbon ising 30 .................................................................. NOTE :

For all operations. includina waehing of dcreena, blanket6 and I

print-washing the water coneumption is as follow8 f o r all type8 Of printing machinee :

(i) Pigment Printing : 40 lJkg (ii) Other Cases of Printing : 50 llkg

(For washing of ecreene), water consumption i e , 100 1/8t").

3-25

Appendix -2

QUANTITY OF WAsrrC WATER PROn TEXTILE XILLS

B 3650 752 206 144 70

c 4282 687 160 121 76

D 6190 1118 181 126 70

E 11000 1314 119 90 75

F 2367 543 229 17 2 75

Average 74

3.26

Appendix-3

B 4282 3.00 15.80 9-00 2.00

C 2367.36 2.62 14.33 8.56 2.40

D 6190 5-47 42.12 22 - 50 2.50

E 3650 4.10 61.85 18.65 3.39

F 423 19.86 53.57 42-99 1.52

Appendix-4

CHEHICALG PREGENT IN COTTON DYRBATHS

Aniline Black Aniline hydrochloride, sodium ferrocyanide, sodium chlorate, pigment, soap, sodium dichromate

Developed

Direct

Naphthol

Sulphur

Dye, penetrant, sodium chloride, sodium nitrite, hydrochloric acid or sulghuric acid developer (beta naphthol) soap or Esulphated soap or fatty alcohol

Dye, sodium carbonate, erodium ohloride, hydrochloric acid, wetting agent or soluble oil or sodium sulphate

Dye. caustic soda, soluble oil, alcohol,soap, soda ash, sodium chloride bam, sodium nitrate. sodium nitrite, sodium acetate

Dye, sodium tsulphide, sodium carbonate, sodium chloride, sodium dichromate, hydrogen peroxide

3.20

Appendix-5

DESIZING

Enzyme Starch Glucose from Starch 45-6 ( 8,645 1

Acid Starch Glucose from Starch 45.6 ( 3,645 )

Polyvinyl Soluble Polyvinyl 2.5 ( 200 1 Alcohol Alcohol

Carboxy Methyl Soluble Carboxy Methyl 3.93 (314 1 -1 lulose Cellulose

SCOURING

Unmercerized Cre ige Fabric

21.4

Mercerized Natural Waxes, Pectins, 16.4 ( 655 1 Creige Fabric Alcohol, etc-

MERCERIZING

Greige Fabric Penetrants such as 12.9 (773) NaOH

Scoured Fabric

Bleached Fabric

1.66 ( 100 1

3.29

BOD CONTRIBUTRD BY CMTON FABRIC MA"ACPUR1NG PROCESSES

BLEACHING

Hydrogen Peroxide (Woven goods)

Hydrogen Peroxide (Knit goods)

Sodium Hypochlorite (Woven goods)

DYEING

Direct (Woven goods)

Direct (Knit' goods)

Developed (Woven goods)

Developed (Knit goods)

Vat (Woven goods)

Vat (Knit goods)

Sulphur (Woven goods)

1.4 ( 8 4 )

Penetrants 23.6 (282 1

0.08 (5)

Sodium Sulphate, 2.59 (62) Soluble Oil

Wetting Agent, etc. 21.1 ( 8 4 )

Penetrant, Sodium 5.22 (125) Nitrate, Developer, Soap, etc.

26.8 ( 107 1

Sodium Hydroeulphite, 19.1 ( 458 ) Soluble Oil, Gelatin, etc.

42.4 (169)

Sodium Sulphide, 24.0 ( 5 7 6 ) Sodium Carbonate

Appendix-5 (Contd. )

Naphthol (Knit goods)

30.6

Fibre Reactive Sodium Ferrocyanide, 6.8 (139) (Woven goods) Sodium Chlorite,

PigJnant

Fibre React ivs (Knit goods)

26.6

PRINTING

Pigment 1.3 ( 101) (Woven goods)

P igme'nt Starch, Glycerol. 1-3 ( 101 1 (Knit goods) Reducing Agent

Vat Dye Detergents 21-5 ( 644 1 (Woven goods) Soager, etc.

Vat Dye 21.5 (8441 '

(Knit goods)

FINISHING

Starch Glucose 2.3 (184)

Resin Cellulosic Solutions 0 .7 (56)

Resin Sulphonated Compounds, Finishing and Detergents, Soape.etc. Curing

Softener 0.25

Appendix-6

tXAFlACl!ERIS!F3CS OF CYMBINgD WAsllE WATBR FROM SYNTHETIC T&XTILB M I U S

2 Total Alkalinity (ae Cam3 mg/l)

552 - .630 590

1070 3 T . D . S . (mg/l) 1060 - 1080 4 S.S. (mu/l) 80 - 130 100

5 BOD tw/l) 180 - 200 190

6 COD (me/l) 420 - 630 525

7 Chloride (mg/l aa C1) 130 - 205 170

0 Sulphate8 (as SO4) 50 - 90 65

9 Calcium (w/l) 14 - 17 15

10 Magnesium (mg/l) 17 - 22 19

11 Sodium (me/l)

12 Potassium (mg/l)

830 - 1050 900

8 - 10 9

13 Per Cent Sodium ( % ) 92.5 - 94.5 93

Total Dieeolved Solids - T . D . S . Sutspended Solids - S.S.

3.32

Appendix-7

AvBRAaE lpoLwTIONAL KMDS OBSERVED I I THE WFP PROCBSSING OF mJTHBTIC FIBRE-PABRICS

Scouring Nylon 10.4 1360 30-40 1880 30-50 20-40 6000-8000

Acrylic 9.7 2190 45-90 1875 12-20 25-50 6000-8000

Polyester - 500- 15-25 - 25-35 5- 15 3000-5000 800

Scouring Rayon 8.5 2830 50-70 3335 25-39 0-3 2000-4OOQ 8! DysingE

Acetate 9.3 2000 40-60 1775 - 1-20 4000-6000

Dyeingl Nylon 8.4 370 5-20 640 20-34 2-40 2000-4000

Acrylic 1.5- 175- 2-40 835- 5-9 5-20 2000-4000 3.7 ZOO0 1970

Polyester - 450- 15-80 - 20-200 2-6 500-1OOO 2700

Sal t Bath Rayon 6.8 50 0.3 4890 4-12 3-7 8000-10000

V i n a l Acrylic 7.1 660 10-20 1190 10-50 3-50 2000-4000

Po lyest er - 650 15-25 .,. 3- 100 3-50 500- 1500 Scouring

Special Rayon - - 20 - 3-100 3-50 3000-5000 Finishing

Acetate - - 40 I 3-100 3-50 4000-6000

Acrylic - - 60 - 3-100 3-50 5000-7000

Polyester - - 2-80 - 3- 100 3-50 1000-3000

SlWWUUE ITOR DISCHARGE OF

- 1. pH 5.5 - 9-0 5.5 - 9.0

2. Biochemical Oxyggn demand, BODg, 20 C

30 150

3, O i l and Grtsatue 10 10

4. Suspended Solids 100 100

5. Dissolved S o l i d s 2 100 2100

8 - Chemical Oxygen Demand 250 - 7. Total Chromium (aa Cr) 2.0 2.0

8 . Sulphide (ae S) 2.0 2.0

9- Phenolic Compounds (as CgH50H)

1.0 5.0

10. Sulphate (as SO41 1000 1000

3.34

DEFINITIONS OF SOME SIGNIFICllliJT POLLVTION PARAMBTERS -~

A. BiMlrhePical Oxygen Depend (BOD)

It is defined as the amount of oxygen required by bacteria

for stabilizing the decomposable organic matter under aerobic

conditions, The BOD test is widely used to determine the

pollutional strength of domestic and industrial wastes in

temns of oxygen that they will require if discharged into

natural water-sources in which aerobic conditions exist.

B. Chemical Oxygen Demand (COD)

The COD determination is a mea~ure of the oxygen equivalent

of that portion of organic matter that is euaceptible to

oxidation by an oxidant. It alao include8 any oxidizale

inorganic eubstances like ferrous sulphate. The COD of a

waate ie generally higher than the BOD because more compounder

.can be chemically oxidized than can be biologically oxidieed.

COD and BOD of textile wastes are correlated.

C. Total Solida. Suspended and Dissolved Solide and Settleable Solids

Matter that remains as residue upon evaporation and drying at

103 to 105OC is termed as solids. Total solidls represent

only those materials in a sample that have a negligible

vapour pressure at 105OC. Ignition of the total solids at

6OO0C removes organic matter leaving behind fixed ( inorganic )

3-35

solids, while loss of weight is interpreted in terms of

volatile (organic) solids. The euapended solid8 are obtained

by filtering the sample thr0ugh.a fine filter and weighing

the dried material on the filter. The dissolved and

colloidal eolide are obtained by evaporating the filtered

ample of water and weighing the residue.

3.36

BIBLIOGRAPHY

1- Environmental Pollution Control - Textile Processing Indwtry - USDC (October, 1978).

2. Industrial Safety and Pollution Control Handbook

- A Joint Publication of National Safety Council,

3, Pollution Control in Textile and Allied Induetries

- S . R . Bhatt, K. Subramanyam and K,R. Swami.

ssm/ P3

3.87