Environmentally friendly techniques in Textiles

Typical Textile Effluent CharacteristicsParameter Woven Fabric Finishing Knit Fabric Finishing Stock & Yarn Dyeing Finishing Cotton Textile Mill Textile MillWoolen Textile MillSyntheti

Prepared By : Mazadul Hasan sheshir ID: 2010000400008

13th Batch (session 2009-2013) Department : Wet Processing Technology Email: mazadulhasan@yahoo.com

Blog : www Textilelab.blogspot.com (visit)

Southeast University

Department Of Textile Engineering I/A 251,252 Tejgaon Dhaka Bangladesh

Prepared By :

Total Textile Process at a Glance

Presently garments industries have become the backbone of the economy of Bangladesh To support those garments industries hundreds of full-scale textile industries have emerged in the past few years and a lot more are going to be setup within a short time These textile dyeing industries are contributing in the development of Bangladesh and at the same time are coursing serious water pollution

It is a matter of great concern to understand and adopt adequate treatment technologies for the remediation of this problem.

ASM Tareq Amin et al. , BTT, 2009 , 2 , 16

Volume of Effluent produced by the different processing of textiles.

500000 pcs

1118 m3

Effluent Quantity/Day

16,500 m31,28,700 m384,500 m3

8500 m3

Wastewater Discharged At

Open Areas

Wastewater Sample

Typical Textile Effluent Characteristics

Parameter Woven

Fabric Finishing

Knit Fabric Finishing

Stock & Yarn Dyeing Finishing

Cotton Textile Mill Textile MillWoolen Textile MillSynthetic

Textile Effluent Characteristics: Bangladesh Perspective

Param eter Minimum

Value

Maximu

m Value BOD

(mg/L)

COD (mg/L)

16.7 17100

SS (mg/L)

5126 15221

MA Rahman, MS Thesis (BUET), 1997

Discharge Quality Standards (By DoE)

Parameter Inland Surface

Water

BOD5(20 o C, mg/L)

50

COD (mg/L)

200

TDS (mg/L)

.

Textile Waste Water Characterization: At

Textile Waste Water Characterization: At

City

City University University Lab (2009): Area Based

Textile Waste Water Analysis

Ashulia Chittagong Dhamrai Gazipur Narshindi Narayangong Savar

Narayangong 10.3

Narshindi 14

Gazipur 9.8

Dhamrai 6.9

Chittagong 11.1

Ashulia 7.2

Area

Ashulia Chittagong Dhamrai Gazipur NarshindiNarayangong Savar

Nrayangong 3260

Narshindi 3109

Gazipur 3304

Dhamrai 538

Chittagong 1483

Environmental Management Methods in

Textiles

1 Good House Keeping, 10-15%

2 Closer Process Control: 30-40%

Reduction in Chemical usage

Recovery & Reuse of Chemicals

Process Modification: Low liquor ratio

machines

Technological Development:

3 Process Chemicals Substitution

PVA/CMC Use

4 ETPs

Types of Effluent Treatment Plants

ETP Diagram

Coagulation and Flocculation

Polyelectrolyte)

Retention Time, Equalization:

Flocculation and Coagulation in

Physicochemical Effluent

Treatment Plants

Coagulation of negative particles

with positive aluminum-complex Flocculation by entanglement with charge-bearing polymers

Different Types of

Different Types of Biological Biological Treatment Plants Dispersed Growth:

Activated sludge (Retention time 48 h)

Membrane Bio-Reactor

Oxidation ditches/ponds Aerated lagoons, stabilization

ponds

Fixed Growth:

Trickling filters Rotating Biological Contactors

(RBCs)

Activated Sludge

Process

Process in which a mixture of

wastewater and microorganisms

is agitated and aerated

Leads to oxidation of dissolved organics

After oxidation, separate sludge from wastewater

Induce microbial growth

Activated Sludge Process

Mixed Liquor in

Secondary Clarifier

Discharge to River or Land Application

Activated Sludge

Process

ETP Flow Chart of Irish Fabrics

Storage Tank Screening Floculation & Coagulation Influent

pH Control Tank Reactor

Secondary Clarifier

Effluent Discharge

Equalisation Tank

Sludge Recycling

Membrane Bio-Reactor (MBR)

The membrane bioreactor (MBR) process that uses both a biological stage and a membrane module has recently been developed for wastewater treatment The bioreactor and membrane module each have a specific function:

1 Biological degradation of organic pollution is carried out in

the bioreactor by adapted microorganisms;

2 Separation of microorganisms from the treated wastewater is

performed by the membrane module The membranes constitute a physical barrier for all suspended solids and therefore enable not only recycling of the activated sludge to the bioreactor but also production of a permeate, free of suspended matter, bacteria, and viruses.

sludge floc

viruses bacteria

MBR Types

In terms of settling tank

replacementIndustrial effluent There are two types of configurations for the membrane array

Permeate

Sludge Discharge Aeration

Membrane

Module

The membranes can be placed either outside or inside the bioreactor

Process Flow chart of MBR:

Effluent from Dyeing house

Equalization Tank

Zero Sludge Discharge of Treated Water

Gravity Feeder Multi chambered Reactor

Figure: Hollow fiber membrane

Hollow fibre membrane module

Figure: Cassette of Hollow Fiber Membranes

Fig: Full view of MBR in Uni-house yarn dyeing factory.

Achievement of zero sludge discharge:

In residual part i.e sludge, new bacteria acts

here activated sludge At the bottom part of the reactor there is a sludge returning pump This pump is regulated by a centrifugal pump When this activated sludge passing through this

pump, due to the high rpm of the motor,

activated (alive) bacteria becomes de-activated (dead) These dead bacteria become the

nutrient of the activated bacteria again This

process continues again & again & thus we can get zero sludge discharge.

Wastewater

Treated Water

Bottom Sludge Treatment Pump Sludge Stress

……

……

Air

Smaller Footprint & More Compactness

Fast Adaptability for changes in Flow rate, COD/BOD ratio and imposed COD

Water Reuse and Recycling

Less Sludge Production

Less or no chemical use and provides highest quality water

No formation of secondary chemical by-products

Easy Scale-up, Expansion and Modification

Absolute barrier for Bacteria and Viruses

Ease of integration into existing plants for upgrade applications

Membrane Bio-Reactor vs Conventional Biological Unit

Low Quality Turbid Water Conventional Multi-Step Tertiary Process

Membrane Bio-Reactors

Chemicals Quantity/dayQuantity/day

Acid 135 L

FeSO4 2580 kgLime 1740 kgAnionic PE 2.16 kgDAP 9.0 kgUrea 18 kg Bacteria 2ookg for 3-5 years

Chemicals Required for 60 m3/hr (Hybrid)

ETP Design & optimization

Computer-Aided Design & Optimization ofEffluent Treatment Plant (ETP)

Developed by the Harbinger Team of Engineers

© Center for Environmental Process Engineering

Shahjalal University of Science &

Technology

Introducing ETP-CAD

Purposes to Design the

Software

To enhance the followings

Design Optimization Performance Analysis

Visualization Taking Decision

to increase efficiency and

accuracy

Language Used: MATLAB

and C

The Team

Jar Test Data Analysis

Aeration Tank

Re Use

Wastewater Reuse in Agriculture

Wastewater Reuse in

Gardening

Eco-Friendly Techniques

are useful Echo-friendly techniques in Textiles.

are useful Echo-friendly techniques in Textiles

Eco-Friendly Techniques:

Solvent Dyeing

r natural

Eco-Friendly Techniques:

Foam Dyeing

Foam Processing Technology:

There are several common commercial applications of foam processing, including carpet dyeing, coating operations, foam dyeing, and foam finishing Textile dyes can be applied through foam media by

replacing water with air

Advantages of foam processing are as follows:

• Reduced water and energy consumption

• Reduced chemical waste

• Less time required for drying (less water to evaporate)

Eco-Friendly Techniques: Super

Increasing consideration of ecological consequences of

industrial processes as well as legislations enforcing the avoidance of environmental problems have caused a reorientation of thinking and promoted projects for

replacement of conventional technologies Supercritical fluid (SCF) dyeing is an emerging P2 technology that uses carbon dioxide as the fluid medium for disperse dyeing on synthetics No water or pollution is

associated with the SCF process

Comparison between Conventional Dyeing and

Supercritical Dyeing

Eco-Friendly Techniques

Eco-Friendly Techniques: Caustic

Soda Recovery

In Bangladesh, Beximco textile uses caustic soda recovery plant (CRP) to recover NaOH from mercerization Fabric production 50,551 meter and 10 ton caustic used for mercerization After mercerization, excess caustic soda goes to CRP and approximately 94% caustic soda is recovered Caustic soda price 40 Tk per Kg They can save much money by using

CRP

Echo-Friendly Techniques: Caustic Soda Recovery Plant at Beximco

Textiles

Eco-Friendly Techniques: Techniques : Ionic Liquid Dyeing

What is ionic liquid? By definition, ionic liquids are low melting salts with

melting temperatures around 100 oC The term “room temperature ionic

liquids” has been assigned to organic salts that are liquid at ambient

conditions

As we know that, the textile industry is believed to be one of the biggest consumers of water The development of ionic liquids that exhibits useful and unique properties has created a huge untapped potential for commercial applications to increase operating efficiencies of many chemical production operations including the processing of textiles Ionic liquids have been called :green solvents: because they are excellent solvents for a broad range of organic compounds In 2006 there were 2000 papers published in different Journals The nanotechnology is a very effective way in various applications Such as fuel cell, industrial processing etc

Eco-Friendly Techniques: Nano

Technology

The nano sized (10 -9 m) metal particles can reflect different colors If the

particles are of the same size as the blue rays, would reflect yellow When these particles are embedded in fiber, the resulting fabric becomes a color

to the eye without any use of dyes or pigments By manipulating the size of these nano particles, researchers can then create virtually any color fabric

Lousiana, has found that ultrasound can boost enzymatic activity during several different types of treatments to cotton fibers Use of enzymes in the cotton

industry has become more popular in recent years Enzymatic treatments have been used for a long time to remove the starch size added to cotton yarns to smooth and protect from breaks during weaving

Eco-Friendly Techniques: Dyeing Machines: Athena 2: SCLAVOS

PRODUCT

Eco-Friendly Techniques: Dyeing Machines: Athena 2: SCLAVOS

No pilling or surface mechanical abrasion

Low tension and shrinkage

Minimal fiber loss Performance Fast process time Very low energy consumption

Very low water consumption

Ease of operation Batch to batch repeatability

Eco-Friendly Techniques: Dyeing Machines: Low liquor machine

In Bangladesh 1:8 machines are popular Recently 1:6

and 1:5 machines are installed by some factories like

ECOTEX LTD

Eco-Friendly Techniques: Right

First Time (RFT) Techniques

Water Prepared Substrate

People Understanding Knowledge & Skills

Profit

Chemicals

RFT Dyeing

Doing all the steps of dyeing and finishing within the

estimated time frame standardize by the factory

The benefits of RFT Technology:

Lower Costs per Batch Increased Output Improved Profit margin Reduced Effluent load Better Customer Service Improved Quality

Eco-Friendly Techniques

For best achievement pollution control at source is the best way

Should think about zero waste concept

Reuse of third time ringing water is a good method to reduce effluent load

4 Chemicals and Power Consumption

5 Construction Cost: Minimum 1 crore

6 Operation cost: 3-3.5 Tk/kg fabric (for combined

ETPs); Monthly around 5-9 lac taka

Central ETP Concept

Effluent should be collected from same

type

of textiles and should be treated in a central ETP for small scale industries.

Central ETP of CEPZ

Central ETP of CEPZ:

Information

24 hours/day operation

1. A large quantity of wastewater generated from

dyeing houses

2. Highly polluted water bodies

3. Treatment essential: various treatment methods

4. Physicochemical, Biological (Conventional & MBR)

and Physicochemical & Biological

5. ETP-CAD can be used for ETP designing and

8. High liquor ratio machines should be replaced by

low liquor ratio machines

9. Ionic liquid dyeing, supercritical fluid dyeing, solvent

dyeing technologies should be used

10. Strong RND in Textile Environment and production

areas required to control pollution

1 “Jago Corporation” (R & D), Ashulia

2 “Pilot Program of MBR in Unihouse Yarn Dyeing Factory”,

Treatment, Disposal and Reuse

By Metcalf & Eddy

3 rd Edition

6 Introduction to Environmental Engineering

By Davis Cornwell

3 rd Edition

7 Books and Papers from internet

8 Treatment of Textile Liquid Waste

Md Akhtaruzzaman, BUET, March 2006

9 Arun Kanti Guha & Md Shariful Islam, BTT, 2009, 2, 43-50.

10 Md Imdadul Hpque and Arun Kanti Guha, BTT, January 2010.

11 Sumit Mondal and Arun Kanti Guha, BTT, Inpress.

My students

I am very much grateful to

Prof Syed Fakhrul Hassan, Chairman and Engr Ahmed Ullah Department of Textile Engineering, Southeast University Engr Tareq Amin, Publisher, BTT., Dr Aub Nabi Khan

Dr Saifur Rahman and Dr Saiful Islam.

1 Yarn Manufacturing Technology