Dye effluents impose hazardous effects on human beings as well as on environment. The present powerpoint deals with some of the decolourization techniques that can be adopted for treating wastewater containing toxic dyes and chemicals

1. 1
Seminar
on
Decolourization of
Textile Dye Effluents
by
Shameembanu A.Shameembanu A.
ByadgiByadgi

2. 2
Water is the main component used in all type of industries
Water used for different processes is not completely utilized & is
discharged as wastewater
Introduction

3. 3
Textile industry is one of the biggest consumer of potable water as well
as chemicals used during textile processing stages
Dyeing & finishing stages are the major producer of wastewater with
complex characteristics
The unused dyes & chemicals are discharged as dye effluents from
various units Dyeing
Bleaching
Wet finishing
Scourin
gNeutralizing
Desizing
Mercerizing
Printing
Others
Carbonizing
Fueling
85%
62%
58%
52%
33%
21%
13%
10%
4%
2%
2%

4. Composition of textile dye
effluents
Parameters Permissible limit
pH 6.5 – 8.5
Biochemical Oxygen Demand (mg/L) 100 – 300
Chemical Oxygen Demand (mg/L) 150 – 250
Total Suspended Solids (mg/L) 100 – 600
Total Dissolved Solids (mg/L) 500 – 2000
Chloride (mg/L) 250 – 1000
Total Nitrogen (mg/L) 70 – 100
4

5. 5
Dye
effluents
Plant
species
Aquatic
animals
Human
beings
Environmen
t
 Interrupt photosynthesis activity
 Decreases soil quality
 Affects plant growth
 Increased level of
danger to life of
aquatic animals
 Hazardous diseases
 Carcinogenic
 Increase aqueous
toxicity, COD & BOD
Effects of dye effluents

6. Textile wastewater is highly coloured
Contain heavy metals that are complex compounds
Cause high electrolyte and conductivity concentrations in the dye
wastewater leading to acute and chronic toxicity problems
Discolour water bodies and increase BOD of the contaminated water
Carcinogenic, mutagenic and generally very harmful to the
environment
Need for dye effluent treatment
6

7. Decolourization techniques
Physical treatment
Chemical treatment
Physico-chemical treatment
Biological treatment
7

8. Physical Treatment
………removal of substances by use of naturally occurring forces, such as
gravity, electrical attraction, and van der Waal forces, as well as by use of
physical barriers
Adsorption
efficient in the removal of pollutants
result of two mechanisms: adsorption & ion exchange
influenced by many physico-chemical factors, e.g., sorbent surface area,
particle size, pH, contact time
8
Methods

9. Activated carbon
most commonly used method
effective for adsorbing cationic, mordant & acid dyes, disperse, direct,
vat, pigment and reactive dyes
performance depends on the type of carbon used and the characteristics
of wastewater
Membrane filtration
can clarify, concentrate and separates dye from effluent
exhibit special features like resistance to temperature, adverse chemical
environment and microbial attack
9

10. Investigation on the removal of direct red dye using
Aspergillus niger and Aspergillus flavus under static
and shaking conditions with modeling
Mohan et. al., 2012
Tamil Nadu
Objective:
To investigate the potential of fungal cultures for decolourization
of synthetic textile dyes
10

11. Decolourization of dyes
Direct red dyes mixed in 100 ml synthetic water at different concentrations
(50, 100 and 200 mg/L)
Isolated organisms in the solution
Incubate
Static condition Shaker
(37ºC and pH7) (150 rpm, 37ºC, pH 7)
OD values measured at maximum absorbance values of each dye at 24th
,
48th
, 72nd
and 96th
hr
Inoculate
Methodology
11

12. % decolourization = OD value for control – OD value for sample
OD value for Control
Average decolourization = C x % D x 1000
100 x t
C = initial concentration of dye (mg/l)
% D = dye decolourization (%)
t = time
12

13. Results and Discussion
13
Figure 1. Decolourization of Direct
red by A.niger at static conditions
Figure 2. Decolourization of
Direct red by A.niger at 150 rpm

14. Figure 3. Decolourization of
Direct red by A.flavus at
static conditions
Figure 4: Decolourization of Direct
red by A.flavus at 150 rpm
14

15. Conclusion
Isolated organisms, Aspergillus niger and Aspergillus flavus have the
ability to decolorize the direct red dye
Aspergillus niger decolourizes the dyes in static condition potentially
where as A.flavus decolourizes at shaking growth condition
The study brings out the ability of Aspergillus sp. to degrade direct dyes
and reinforces the potential of these fungi for the decolourization of
textile effluents
15

16. Chemical Treatment
Chemicals are used in an array of processes to expedite
disinfection
Used alongside biological and physical cleaning processes to
achieve various water standards
16

17. 17
Ozonation
 A good oxidizing agent
 The dosage applied is dependent on the total colour and residual COD
to be removed
Oxidative process
 commonly used method for decolourization by chemical means
 main oxidizing agent used is hydrogen peroxide
 removes the dye effluent by oxidation in aromatic ring cleavage of the
dye molecules
Methods

18. Fenton reagent
 suitable for the treatment of effluents which are resistant to biological
treatment or poisonous to live biomass
 Performance depends on good flock formation and settling quality
18
Photo chemical process
 Degrades dye molecules into carbon dioxide and water by UV
treatment
 Degradation is caused by the production of high concentrations of
hydroxyl radicals
 The rate of removal is influenced by the intensity of UV radiation, pH,
dye structure and the dye bath composition

19. Decolourization and removal of COD and BOD from
raw and biotreated textile dye bath effluent through
advanced oxidation processes (AOPS)
Muhammad et. al., 2008
Lahore, Pakistan
Objective:
To study the effect of advanced oxidation processes (AOPs) on
decolourization of raw and biotreated textile dye bath effluents
19

20. Methodology
20

21. Table 1. Characterization of raw and biotreated textile dye bath
effluent
21
*Absorbance of colour at 465nm
Parameters Raw Biotreated
COD (mg/l) 750 154
A* (Colour) 1.8 1.2
BOD (mg/l) 261 76.2
pH (units) 12.1 8.4

22. Figure 5. Comparison of AOPs in terms of COD, color & BOD removal of
raw textile effluent
Results and Discussion
22

23. Figure 6. Biodegradability improvement of raw textile effluent
23

24. Figure 7. Comparison of AOPs in terms of (%) removal of COD, color & BOD
of biotreated textile effluent
24

25. Figure 8. Biodegradability improvement of biotreated textile effluent
25

26. Conclusion
The application of a combined method i.e., biotreatment and AOPs for
treating dye bath effluent was advantageous
The combined approach allowed better achievement of decolourization
efficiency and reduced treatment costs
Application of AOPs to biotreated textile effluent was more effective
than raw effluent
Ozonation process for raw textile effluent was better for decolourization
than the AOPs applied
26

27. Decolourization of Textile dye waste waters by
Hydrogen peroxide, UV and Sunlight
Dinarvand, 2014
Iran
Objective:
To investigate the efficiency of decolourization of the azo dye
with UV radiation in the presence of H2O2
27

28. Methodology
28
Figure 9. UV radiation constructed reactor box
Ultraviolet radiation treatment
Specifications
60 x 40 x 30 cm
UV lamp of 30W
Radiation wavelength 254nm
Solar radiation treatment
Quartz tubes with 3mL of
wastewater
Placed at 45º angle
Exposed to sunshine
(12pm – 4pm)
Assessed for colour removal

29. Results and Discussion
Figure 10. Decolourization by UV irradiation in the absence of H2O2
29

30. 30
Figure 11. Decolourization by UV irradiation in the presence of H2O2

31. 31
Figure 12. Decolourization by UV radiation at pH 7 with different concentrations
of H2
O2

32. Optimum operating conditions of Solar light/H2
O2
In the presence of 0.143M H2
O2
solution, maximum of 97%
decolourization at pH 4 and minimum of 40% decolourization at pH 10
was achieved after 90 minutes
32

33. 33
Conclusion
 Decolourization percentage with UV radiation at 60 minutes in presence
of 0.014M H2
O2
at 50°C temperature was 99.8
 The presence of 0.143M of hydrogen peroxide caused maximum per
cent decolourization (97%) in case of solar light/H2O2
 It was suggested that the decolourization of dye DB-177 should be
performed in the presence of ultraviolet radiation

34. 34
Physico-chemical Treatment

35. 35
Methods
Sedimentation
 Removal of floc by solid-liquid separation
 Achieved by using low, medium and high rate settlers
 The rate is determined by the speed at which water and sludge are separated
Coagulation
 Destabilization or neutralization of negative charges in the wastewater by
addition of coagulant during rapid mixing and very short contact time
 The quantity of coagulant applied depends on the quality of water
 Commonly used coagulants are ferric chloride, ferric sulphate, aluminium
sulphate, lime, etc

36. 36
Flocculation
 Referred to formation of flocs and bridges
 Previously formed flocs group together, increase in volume and density,
later gets sedimented
 Achieved by applying a gradient and contact time varying between 15
minutes and 3 hours

37. Removal of reactive yellow dye from aqueous solutions
by using natural coagulant (Moringa oleifera)
Veeramalini et. al., 2012
Chennai, India
Objective:
To examine the decolourization of the Reactive Yellow 145 dye
by Moringa oleifera under static conditions
37

38. Methodology
Preparation of coagulant
38

39. 39
Coagulation study (Jar test)
1000ml dye solution
Add coagulant with rapid mixing at 100rpm for 2 min
Slow mixing at 40rpm for 30 min
Kept for sedimentation for 30 min
Filtered using Whatman filter paper
Analyzed for colour removal

40. Results and Discussion
Figure 13: Effect of coagulant dose on the removal of colour
40

41. 41
Figure 14: Effect of contact time on decolourization

42. 42
Figure 15. Effect of pH on decolorization of Reactive yellow dye by
M.oleifera

43. Conclusion
 100mg Moringa oleifera gave approximately 95% COD reduction
after10 minutes contact time while 500mg M.oleifera reduced colour by
90% at pH 10
 100mg coagulant enhances efficient removal of COD and colour in the
coagulation process
43

44. Decolourization and COD reduction efficiency of
magnesium over iron based salt for the treatment of textile
wastewater containing diazo and anthraquinone dyes
Verma et. al., 2012
Odisha, India
Objective:
To investigate the effectiveness of MgCl2 & FeSO4 for
decolourization and COD reduction
44

45. 45
Methodology
Materials used
Concentration
(mg/L)
Function
Starch 1000 Sizing agent
Acetic acid 200 Sizing agent
Sucrose 600 Sizing agent
Dyes 200 Colouring agent
NaOH 500 Hydrolysing agent
H2SO4 300 pH neutralization
Na2CO3 500 Fixing agent
NaCl 3000 Fixing agent
Sodium lauryl sulphate 100 Scouring agent
Table 2. Chemical constituents used for the preparation of synthetic textile wastewater

46. Optimum coagulant dosage: Determined by Jar test
COD reduction: COD was analysed as per closed reflux colourimetric method
Removal (%) = (Aut
– At
) x 100
Aut
Aut
& At
= absorbencies of untreated and treated wastewater samples
46

47. Results and Discussion
Figure 16a. Colour removal (%) & COD reduction of textile wastewater
containing RB5 (Reactive Black 5)
47

48. 48
Figure 16b. Colour removal (%) & COD reduction of textile wastewater
containing CR (Congo Red)

49. 49
Figure 16c. Colour removal (%) & COD reduction of textile wastewater
containing DB3 (Disperse Blue 3)

50. 50
Figure 16d. Colour removal (%) & COD reduction of textile wastewater
containing RB5+CR

51. 51
Figure 16e. Colour removal (%) & COD reduction of textile wastewater containing
CR+DB3

52. 52
Figure 16f. Colour removal (%) & COD reduction of textile wastewater containing
RB5+DB3

53. 53
Figure 16g. Colour removal percentage for textile wastewater containing
RB5+CR+DB3

54. Conclusion
MgCl2
in combination with lime was superior over the other coagulants
for decolourization & COD reduction
More than 99% decolorization efficiency & 63% COD reduction
efficiency was observed using MgCl2
/Lime as coagulants
MgCl2
/Lime can be used as an efficient coagulant system for the
treatment of textile wastewater
54

55. 55
Biological Treatment
 Remove dissolved organics from effluent and thus reduce chemical
and biological oxygen demands of the effluents
 Achieved biologically wherein bacteria/fungi are used to convert the
colloidal and dissolved carbonaceous organic matter into various gases

56. 56
Methods
Aerobic Treatment
 Dissolved oxygen is utilized by microorganism and finally wastes are
converted into biomass and carbon dioxide
 Organic matter is partially oxidized and some of the energy produced is
used for generating new living cells under the formation of flocs
 Bacteria and fungi have been most widely studied for their capability to
remediate textile and dye wastewaters

57. 57
Anaerobic treatment
 Involves an oxidation-reduction reaction with hydrogen rather than free
molecular oxygen aerobic system
 Dyes are degraded and converted into aromatic amines, later the
produced aromatic amines are degraded by aerobic biodegradation

58. Evaluation of microbial systems for biotreatment of
textile waste effluents in Nigeria: Biodecolourization
and biodegradation of textile dye
Agarry and Ajani, 2011
Nigeria
Objective:
To evaluate the remediation potential of isolated micro organisms
to decolourize the dye and reduce the COD & BOD of textile effluents
58

59. Methodology
Micro organisms
Bacterial species
Pseudomonas fluorescence
Pseudomonas nigificans
Pseudomonas gellucidium
Fungal species
Aspergillus niger
Fusarium compacticum
Proteus morganii
59
Batch microbial treatment
Autoclaved mineral salt medium (0.8L) + 3L
textile waste effluent in a bioreactor
Add inoculum (200ml) aseptically to make 4L
working solution
Stir at room temperature with agitation speed of
300 rpm
Ferment for 14 days
Filter the solution through Whatman paper No. 1
& centrifuged for 10 minutes
Analysis of decolourization, COD & BOD

60. 60
% decolourization = A – B x 100
A
A = Initial absorbance
B = Final absorbance
Determination of COD & BOD
COD – standard colourimetric method (APHA – AWWA, 1985)
BOD – 5 day BOD test
Determination of decolourization percentage

61. Results and Discussion
Figure 17. Decolourization of textile waste effluents by isolated microbial species
[A = P.flourescence, B = P.nigificans, C = P.gellucidium, D = A.niger, E = P.morganii,
F = F.compacticum]
61
Order of percent dye decolourization
A. niger > P. fluorescence > P. morganii > F. compacticum > P. nigificans > P.
gellucidium

62. Figure 18. COD reduction of textile waste effluents by isolated microbial species
[A = P.flourescence, B = P.nigificans, C = P.gellucidium, D = A.niger,
E = P.morganii, F = F.compacticum]
62

63. 63
Figure 19. BOD reduction of textile waste effluents by isolated microbial species
[A = P.flourescence, B = P.nigificans, C = P.gellucidium, D = A.niger,
E = P.morganii, F = F.compacticum]

64. Figure 20. Effect of dye concentration on decolourization by binary mixed culture of
P.fluorescence and A.niger
64

65. Conclusion
Aspergillus niger, Pseudomonas fluorescence, Proteus morganii,
Fusarium compacticum, Pseudomonas nigificans & Pseudomonas
gellucidium have a significant potential for dye decolourization and
degradation
65

66. Biological treatment of azo dyes and textile industry
effluent by newly isolated White rot fungi
Schizophyllum commune and Lenzites eximia
Selvam and Shanmuga, 2012
Coimbatore
Objective:
To study the dye decolourization of azo dye and textile industry
effluent treatment by White rot fungi in batch and continuous mode
66

67. Methodology
67
Decolourization of azo dyes
C-limited medium containing congo
red, methylorange & erichrome black-T
(each 50µM)
Spore suspension of S.commune &
L.eximia
Rotary shaker (120rpm) at 39ºC for
6 days
Filtered through G3 sintered glass filter
Decolourization of textile industry
effluent
C-limited medium containing textile dye
effluent (950ml)
50ml of spore suspension (105 spore/ml)
of S.commune & L.eximia
Maintained at 39ºC for 6 days
Analysed for colour removal
Inoculate Inoculate
Incubate

68. Results and Discussion
Figure 21. Removal of Azo dyes from
aqueous solution by Schizophyllum
commune
68

69. Figure 22. Removal of Azo dyes from aqueous solution by Lenzites eximia 69

70. Figure 23. Colour removal of textile
industry effluent by Schizophyllum
commune
Figure 24. Colour removal of
textile industry effluent by
Lenzites eximia
70

71. Conclusion
Schizophyllum commune was more efficient than Lenzites eximia for the
treatment of azo dyes and textile dye industry effluent in both batch
mode and continuous mode
The batch mode treatment of textile industry effluents by Schizophyllum
commune was more efficient when compared to continuous mode
71

72. 72
Summary
Conventional technologies to treat textile wastewater include
combinations of biological, physical and chemical methods, but require
high capital and operating costs
Biological treatments can efficiently remove dyes from large volumes
of wastewater at low cost
Need of the day is to substitute hazardous chemicals by using
environment friendly methods
Best approach to reduce wastewater discharge is to manufacture eco-
friendly products and to modify certain areas of textile processing in
to avoid toxicity

73. 73
“Better handling of textile waste and
their efficient disposal will surely be an
appropriate step to maintain ecological
balance on earth”