Assessment of Counter Current Washing and Change in Rope...

Presented by: Filiz MOROVA

İzmir Development Agency

Assessment of Counter Current Washing and Change in Rope Route for Water Use Minimization in a Wet

Processing Textile Mill

Textile Manufacturing is one of the Largest Industrial Consumers of Water

• “Environmental Technology Best Practice Program, guide Code EG98, Water Use in TextileDyeing and Finishing” states that;

the water consumption is:

150-200 kg/kg of product

Reducing the Water Consumption inTextile Mills

Reducing the water consumption REDUCE WASTEWATER GENERATED&INCREASE THE COST EFFECTIVENESS.

In the Guide called as “A Step Towards Cleaner Production”,Susan Barclay and Chris Buckley states that;

Within any process, there are five main aspects that should be taken

into account when considering the implementation of waste

minimisation.

• raw materials used and other input materials such as water• the type of technology,

• the manner is which the process is executed,

• the products that are formed, and• the wastes and emissions that are generated.

The Textile Mill Studied

The Textile Mill studied;

• is one of the major mills in Turkey

• has a capacity of 20 000 ton denim fabric per year

• includes Cotton Fiber Production, Dyeing, Sizing and Finishing

8

The Textile Mill Studied

�The production is 24 hours a day & 3 shifts/day

�The water consumption of 2000 m3/day

�Chemical consumption of 1000 ton/month

�Over 100 chemicals used

�It has own WWTP and Co-generation Units

9

Production Flow

COTTON FIBER

PRODUCTION DYING PROCESSES

WEAVING

FINISHING PROCESSES

150-200 kg of water/kg of product

SIZING PROCESSES

Dyeing Processes

• Dyeing Machine includes the equipment which is used for preparation and softening processes.

The flow chart for Dyeing Processes in the Mill;

Preparation Pre-Washing Dyeing Back-Washing

Water consumed in these processes is;

about 40 % of the total water used through this whole production line of the Mill

Softening

How to minimize the waste- How to reduce water consumption -

NEW TECHNIQUES

WATER CONSUMPTIONREDUCTION STUDY

PROCESS REVIEWING

DETERMINING THE WATER USAGE IN DYING PROCESS

ASSESSMENT OF THE WATER CONSUMPTION REDUCTION OPTIONS

ASSESSMENT OF TECHNICAL FEASIBILITY OF CHOSEN OPTIONS

Through out the study;

• Brain storms with the managers of the selected Textile Mill / Site Visits

• Literatural Reviews

European Integrated Pollution Prevention and Control (IPPC)

Reference Document on Best Available Techniques (BAT) for the

Textiles Industry was accepted as main reference document.

WATER CONSUMPTIONREDUCTION STUDY

WATER CONSUMPTION REDUCTIONSTUDY

• Rerouting the Rope-Guide

• Counter-Current Washing in Back-

washing

Rerouting the Rope-Guide

What is Rope-Guide?

• Different Dyeing recipes exist for Different Denim Products.

• Each recipe has its own application method in the Textile Mill.

• There are four Dyeing Machines in the Mill, which includes;

Preparation, Pre-washing, Dyeing and Back-washing Units in different numbers of their application tanks.

•Therefore, there are some differences of applications of different Dyeing recipe.

• To adjusting the following Dyeing recipe application to the Dyeing machine, Rope-Guide is used in the Mill.

Prepara

tion

Tank

Pre-

w ash

ing 1

Pre-

w ash

ing 2

Pre-

w ash

ing N

Dyeing 1

Dyeing 2

Dyeing N

Back-

washi

ng 1

Back-

washi

ng 2

Back-

washi

ng N

Route of Rope-Guide (Dyeing Recipe A)

Water Flow

New Route of Rope-Guide (Dyeing Recipe B)

Rerouting the Rope-Guide

• Rope guide is fixed to the rope which will be going through the

Dyeing processes, and it determines the route of the rope which will

be dyed.

• ReroutingRerouting is to change the route of the rope-guide in an

environmental friendly way, which provides reduction of water

consumption.

• 5 dyeing recipes (X, Y, Z, W, U) in different dyeing machines

– Application Frequency within the period of the study:

30% of the number of the total dyeing recipe

– Rerouting is applicable

• Rerouting alternatives were determined and application conditions were examined and application was achieved.

• Water saving was determined.

• The effect of varying dyeing time was observed.

– The duration of dyeing can be changed between 165 min and 1000 min.

Rerouting the Rope-Guide Materials and Methods

Dying Tank used as

washing tank

Washing

TankWashing

Tank

Fresh water feeding tank

Q

Q/3 Q/3Q/3

Dying Tank used as

washing tank

Washing

TankWashing

Tank

Fresh water feeding tank

Q

Q/2 Q/2

Fresh

water

Dying Machines

3 and 4

Dying Machines

1 and 2

Q

Q/2 Q/2

q

Rerouting the Rope-GuideX Type Dyeing recipe/Machine 1

V=2600 L V=2600 L V=2600 L V=2600 L V=2600 L V=2600 L V=2600 L V=2600 L V=2600 L V=2600 L

V=1000 L V=1000 L V=1000 L

Dying 1

Dying 2

Dying 3

Dying 4

Dying 5

Dying 6

Dying 7

Dying 8

Dying 9

Dying 10

Backwashi

ng 3

Backwashi

ng 2

Backwashi

ng 1

New route of guide-rope

Water (new dying method)

Old route of guide-rope

Water (Old dying method)

33.3 L/min

33.3 L/min

33.3 L/min

33.3 L/min 33.3 L/min 33.3 L/min

33.3 L/min

33.3 L/min

33.3 L/min

33.3 L/min

33.3 L/min

33.3 L/min

• 7 dyeing tanks

• There isn’t any extra freshwater feeding tank for dying tanks BUT..

66.6 L/min

66.6 L/min

66.6 L/min

66.6 L/min

66.6 L/min

66.6 L/min

Rerouting the Rope-Guide X Type Dyeing recipe

• Water consumptions and water saving data for X type dying in machine 1

Amount of water consumed for back-washing in old dying method (L) 63800

Amount of water consumed for back-washing in new dying method (L) 56000

Water saving (%) 12

• 265 minutes (6625 m of rope to be dyed, machine velocity=25 m/min)

• maximum water saving is 19 % where the minimum water saving is 4 %

0

2

4

6

8

10

12

14

16

18

20

0 200 400 600 800 1000 1200

Duration of dying (min)

Wate

r savi

ng p

er d

yin

g (%

)

Amount of water consumed for back-washing in old dying method: (265 min * 200 L/min) + (1000 L/tank * 3 tank) + (2600 L/tank * 3 tank) = 63800 L

Amount of water consumed for back-washing in new dying method:

(265 min * 200 L/min) + (1000 L/tank * 3 tank) = 56000 L

Rerouting the Rope-Guide Y Type Dyeing recipe/Machine 2

Preper

atio

n

Prewas

hing

1

Prewas

hing

2

Prewas

hing

4

Dying 9

Dying

8

Dying 7

Dying

10

25 L/min

25 L/min

25 L/min

25 L/min

25 L/min

25 L/min

25 L/min

Dying

1

Dying

2

Dying

3

Dying

4

Dying

5

Dying

6

New route of guide-rope

Water


V=600 L

V=1000 L V=1000 L V=1000 L V=1000 L

V=2600 L V=2600 L V=2600 L V=2600 L V=2600 L V=2600 L V=2600 L V=2600 L V=2600 L

V=2600 L

Prewas

hing

3

25 L/min

• 4 dyeing tanks are required for this type.

• In old method: 6 dyeing tanks are used as pre-washing tanks.

Flow is splitted into 10 freshwater pathways.

Rerouting the Rope-Guide Y Type Dyeing recipe

•Water consumptions and water saving data for Y type dying in machine 2

Amount of water consumed for pre-washing in old dying method (L) 40600

Amount of water consumed for pre-washing in new dying method (L) 25000

Water saving (%) 38

• Duration of Dyeing is; 210 minutes

• Maximum water saving is 45 %

• Minimum water saving is 14 %.0

10

20

30

40

50

0 200 400 600 800 1000 1200


Wa

ter

sa

vin

g p

er

dy

ing

(%

)

Amount of water consumed for pre-washing in old dying method: (210 min * 100 L/min) + (1000 L/tank * 4 tank) + (2600 L/tank * 6 tank) = 40600 L

Amount of water consumed for pre-washing in new dying method:


Rerouting the Rope-Guide Z Type Dyeing recipe/machine 3

Dying 2

Dying 3

Dying 4

Dying 5

Dying 6

Dying 7

Prewashi

ng 4

Prewashi

ng 3

25 L/min

25

L/min

25

L/min

Preperati

on

Prewashi

ng 1

Prewashi

ng 2

25 L/min

25 L/min

25

L/min

Dying 8

Dying 9

Dying 10

Dying 1

25

L/min

25 L/min

20 L/min

20 L/min

V=600 L V=1000 L

V=1000 L

V=1000 L

V=1000 L

V=2600 L

V=2600 L

V=2600 L

V=2600 L

V=2600 L

V=2600 L

V=2600 L

V=2600 L

V=2600 L

V=2600 L

New route of guide-ropeWater (new dying method)


Water (old dying method)

9 dyeing tanks are required.

In old method: 1 dyeing tank is used as a pre-washing tank.when a dying tanks is used as a washing tank, there shouldbe an extra total flow coming from the tank which feedsdying tank with freshwater. This total flow is 10-20 L/min.

Rerouting the Rope-Guide Z Type Dyeing recipe

Water consumptions and water saving data for Z type dying in machine 3

Amount of water consumed for pre-washing in old dying method (L) 51000

Amount of water consumed for pre-washing in new dying method (L) 41000

Water saving (%) 20

• In this case dying lasts 370 minutes

• Maximum water saving is 23 %.

• Minimum water saving is 18 %. 0

5

10

15

20

25

0 200 400 600 800 1000 1200


Wa

ter

sa

vin

g p

er

dy

ing

(%

)

Amount of water consumed for pre-washing in old dying method: (370 min * 100 L/min) + (370 min * 20 L/min) + (1000 L/tank * 4 tank) + (2600 L/tank) = 51000 L

Amount of water consumed for pre-washing in new dying method:


• According to data obtained from the facility; for the three months, in which the rerouting

has taken place, the percentage of those types of dyeing recipes are determined as 30 % of

the total production.

• Preparation, dying, washing and softening processes are defines “rope dyeing processes” by

the facility.

Rerouting the Rope-Guide Reduction in Water Consumption

Amount ofconsumed

water in rope

dyeing process(L)

Washing water

consumption

(new method) (L)

Washing water

consumption

(old method)

(L)

Difference

(L)

Reduction in total

(X,Y,Z,W,U) water

consumption (%)

X 110872 56000 63800 7800 7,0

Y 93479 25000 40600 15600 16,7

Z 265683 41000 51000 10000 3,8

W 156767 85500 93300 7800 5,0

U 163750 92000 99800 7800 4,8

Total 790551 299500 348500 49000 6,2

March-April-Mai total water use for rope dying processes

Amount of consumed water (L)

March 42475000

April 28191000

Mai 31736000

Total 102402000

Rerouting the Rope-Guide Reduction in Water Consumption

Water consumed in three months for X,Y,Z,W,U type dyings (30% of total consumption) can be calculated as follow;

102402000 L * 0.3 = 30720600 L

Water reduction amount in three months is equal to

30720600 L * 0.062

= 1,904,677 L

• Within the selected five specific type of dying the effect of the

method was investigated. By investigating this effects, it was

obviously seen that water saving can be achieved.

• The effect of duration of dying on water saving was also

investigated:

when there is an additional freshwater feeding tank to the washing

tank there is not significant effect of duration of dying on the water

saving percentage.

Rerouting the Rope-Guide Conclusion

Counter-Current Washing in Textile Industry

• The more important consideration is to achieve the required washing efficiency by using less amount of rinsing water.

• The counter-current washing principle is the most common and efficient one among those techniques.

Counter-current washing is often practiced by introducing raw water into the last wash of the washing series.

The wastewater is then circulated from the last step to the next preceeding step and so on up the line.

The cleanest product is washed with the cleanest water and and the most contaminated product is washed with dirtiest water. The system leads to huge savings in water use.


Material Flow

Water Flow


Typical water savings obtained by counter-current washing

Number of washing tank Water saving

(%)

2

3

4

5

50

67

75

80

Source:(US EPA, 1995)

Since preparation and dying processes are typically continuous, counter-current washing can be used to great advantage for water conservation in washing processes. The principle of counter-current washing in textile industry is simple and usually not expensive or difficult to implement.

Counter-Current Washing in TextileIndustry

•Sillanpää states that the one of the developed techniques is the split flow counter current washing which is the variation of counter-current washing.

•Because the various reasons for each industry, the counter-current washing was modificated and called as split flow counter current washing

Product

Flow

Fresh

water

Wastewater

Washing 2

Washing 1

Washing 3

Washing 4

Wastewater Wastewater

Filtrate System Saving in

water

(%)

Direct counter-current 50-80

Split flow counter-current 40-65

Source: Sillanpää, 2005

Reasons for using split flow counter current washing

• The company uses cotton as raw material.

• According to Textile Sector Environmental Report; in opposition of dying of synthetic raw materials, counter-current washing applications are not common in cotton dying. The cotton fiber pollution is the main reason for that.

• For the last washing tank, from which water is sent to the previous, the cotton fiber pollution is minimum. Therefore using filter is a solution and does not create a clogging problem.

• But for the washing tanks before the last tank, the fiber pollution is a problem, because the cotton lets its fiber in a suspended situation in these tanks at most. For this reason, it is thought that the filter clogging would be a big problem if direct counter-current washing were applied.


Product

Flow

Fresh

water

Wastewater

Washing 2

Washing 1

Washing 3

Washing 4

Wastewater WastewaterFilter

• 3 dyeing recipes (A, B, C) were selected.

• Two methods of washing was applied.

– Normal Flow Washing (old system)

– Split flow counter current washing (new system)

F<Q where the product quality is said to be the same.

• Water saving was determined.

• Analysis of wastewater characteristics for water from each washing tank was done to compare with literatural truth.

• Samples from each washing tanks were taken after the retention time was exceed.

Counter-Current Washing in Textile Industry Materials and Methods

Product Flow

Fresh water

WW

21

3 4

WW WW WW

Product Flow

Fresh water

ww

21 3 4

ww wwFilter

Q FF/3 F/3 F/3

Q/4 Q/4Q/4 Q/4

Counter-Current WashingA Type recipe

Product Flow

Fresh

water

ww

Washing 2

Washing 1

Washing 3

ww ww

300 L/min

100 L/min 100 L/min 100 L/min

2 3

Product Flow

Fresh water

Washing 1

Washing 2

Washing 3

ww ww

Filter

185 L/min92,5 L/min 92,5 L/min

a

b

c

Flow diagram for new system washing of dying type A

Flow diagram for old system washing of dying type A

• Each washing tank is 1000 L

• 500 min washing period

•Retention time is 10 minute for each tank

• Flowrate of freshwater is 300 L/min

•Each washing tank is 1000 L

•115 min washing period

• Retention time is 10.8 for first two and 5.4 min.

•Flowrate of freshwater is 185 L/min

1

Counter-Current Washing B Type recipe

Flow diagram for new system washing of dying type B

Flow diagram for old system washing of dying type B

• First washing tank is 1600 L, where others are 1000 L.


•Retention time is 30 min for first tank where it is 18 min for others.


•First washing tank is 1600 L, where others are 1000 L.


• Retention time is 39 min for first tank and 24.3 min for 2,3,4 and 6 min for WT 5.


Product

Flow

Washing

2

Waste

water

Washing

4

Washing

3

Waste

water

Waste

water

275 L/min

55 L/min

55 L/min

55 L/min

11

2 3

Waste

water

Washing

1

Waste

water

Washing

5

4 5

55 L/min

55 L/min

Product

Flow

Fresh

water

Washing 2

ww

Washing 3

ww

Washing 5

Filter

165 L/min41,25 L/min

Washing 1

ww

Washing 4

ww

41,25 L/min

41,25 L/min

41,25 L/min

a

b

cdef

Counter-Current WashingC Type recipe

Flow diagram for new system washing of dying type C

Flow diagram for old system washing of dying type C

• First washing tank is 1600 L, RT =30.7 minutes

• the other WT 1600 L with RT=19.2 minutes



•First washing tank is 1600 L, where others are 1000 L.


• Retention time is 47 min for first tank and 29.6 min for 2,3,4 and 7.5 min for WT 5.


Product

Flow

Washing

2

Wastew

ater

Washing

4

Washing

3

Wastew

ater

Wastew

ater

260 L/min

52 L/min 52 L/min 52 L/min

1 2 3

Wastew

ater

Washing

1

Wastew

ater

Washing

5

4 5

52 L/min 52 L/min

Product

Flow

Fresh

water

Washing 2

ww

Washing 3

ww

Washing 5

Filter

135 L/min33,75 L/min

Washing 1

ww

Washing 4

ww

33,75 L/min

33,75 L/min

33,75 L/min

a

b

cdef

Counter-Current Washing A Type recipe

Results for each tank in dying type A, old system

Dying Type A

Old System

Washing

Tank 2

(2)

Washing

Tank 3

(3)

TSS (mg/L) 196 44

TDS (mg/L) 2348 1760

Color (Pt-Co) 6920 3320

Turbidity(NTU) 690 389

Alkalinity (mg/L

CaCO3) 870 680

COD (mg/L) 1002 400

Conductivity

(s/cm) 3470 2760

pH 11,1 10,62

Results for each tank in dying type A, new system

Dying Type ANew System

Washing Tank 2

(c)

Filter Inlet(Washing

tank 3)

(a)

TSS (mg/L) 322 34

TDS (mg/L) 5198 882

Color (Pt-Co) 9060 2515


Alkalinity (mg/L CaCO3) 1874 310

COD (mg/L) 1372 264,5

Conductivity (Ks/cm) 8660 1221

pH 11,8 9,5

Pollution concentration is less in last washing tanks for new system where it is more in 2nd washing tank.

Counter-Current WashingB Type recipe

Results for each tank in dying type B, old system Results for each tank in dying type B, new system

Dying Type B

Old System(1) (5)

TSS (mg/L) 206 26

TDS (mg/L) 13456 688

Color (Pt-Co) 8600 4750


Alkalinity (mg/L

CaCO3) 3300 220

COD (mg/L) 3740 238

Conductivity ()s/cm) 17850 969

pH 12,03 9,75

Dying Type B

New System

1

(f)

5

(a)

TSS (mg/L) 546 22

TDS (mg/L) 24134 558

Color (Pt-Co) 22300 935



COD (mg/L) 4823 102


pH 12,17 9,08

Counter-Current WashingC Type recipe

Results for each tank in dying type C, old system Results for each tank in dying type C, new system

Dying Type C

Old System (1) (5)

TSS (mg/L) 54 35

TDS (mg/L) 2688 908

Color (Pt-Co) 2280 1330



COD (mg/L) 511 125


pH 11,12 10,18

Dying Type C

New System

1

(f)

5

(a)

TSS (mg/L) 108 14

TDS (mg/L) 3592 632

Color (Pt-Co) 2860 715



COD (mg/L) 650 87


pH 11,81 9,48

Counter-Current Washing Reduction in Water Consumption

Old System

water consumption

(L/min)

New System

water consumption

(L/min)

Reduction in water

consumption

(%)

Type A 300 185 38

Type B 275 165 40

Type C 260 135 48

• All the processes in the Textile Mill were investigated to identify

the water conservation opportunities.

• As well as the Literatural Review, after some site visits to the facility

the processes were detected and the possible changes especially

related to the water consuming processes were determined.

• Possible water use reduction techniques were detected.

• The techniques were applied in the facility.

Conclusion for the Presentation

• The water conservations obtained through the techniques of “Rerouting the Rope-Guide” and “Split Flow Counter Current” were determined in the application base.

• For counter-current washing, the washing water were analysed to compare the character of it, with the literatural knowledge.

Future Work:

Determination of the total effect of this water conservationapplications on the water consumption of the facility.

Conclusion for the Presentation

This study was funded by The Scientific and Technological Research Council of Turkey

Studies on Adopting the EU IPPC Directive in Textile Sector: BAT Applications

Project No: 105Y088

Thank You for your Attention and Interest on Cleaner Production !!!

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Assessment of Counter Current Washing and Change in Rope...

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