EPA-600/2-78-098
May 1978 Environmental Protection Technology Series
TEXTILE DYEING WASTEWATERS:
CHARACTERIZATION AND TREATMENT
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
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This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
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vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
EPA REVIEW NOTICE
This report has been reviewed by the U.S. Environmental Protection Agency, and
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EPA-600/2-78-098
May 1978
TEXTILE DYEING WASTEWATERS:
CHARACTERIZATION AND TREATMENT
by
Roderick H. Horning
American Dye Manufacturers Institute
One East 57th Street
New York, New York 10022
Grant No. R803174 I?'3' ^Iron;B3ntal Protect!., A«e»cy,
Program Element No. 1BB036 !£* 1°n 5' Li*>i*»ry <5?L-16)
6JV S. learfcern Str»*t, loom 1670
Chioaeo, U, I0«04
EPA Project Officer: Max Samfield
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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ABSTRACT
Treatability of wastewaters from selected typical dye baths
by biological, chemical and physical means was examined.
Twenty systems were selected to provide a broad cross section
of dye classes, fibers and application techniques. Wastes
were produced using typical formulations on a pilot plant
scale to provide desired control and simulate plant conditions,
Raw wastes were characterized. Treated wastes were evaluated
for color and TOC. Biological treatability at several con- •
centrations was examined without seed, with domestic sewage
and acclimated seed. Wastes generally were compatible with
the biological process; color reduction was incomplete. No
single treatment was effective for both color and TOC removal.
Chemical treatment with ozone decolorized the wastes. Physi-
cal treatments were done with alum, lime and activated carbon
using jar tests. Disperse, vat and sulfur dyes were most
effectively decolorized by coagulation procedures and carbon
was most effective for decolorizing reactive, basic, acid
and azoic dyes. A statistical evaluation of heavy metal
content of dye baths and a compendium of dye bath additives
and dyeing methods is included.
This report was submitted in fulfillment of Grant Number
R803174 by the American Dye Manufacturers Institute under
the partial sponsorship of the Environmental Protection
Agency. Work was completed as of September 1975. This
work covers a period from June 30, 1974 to December 29, 1975.
Work was completed in September, 1975.
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CONTENTS
Page
Abstract "•
Figures iv
Tables x
Abbreviations And Symbols xiv
Acknowledgement . xv
I Conclusions 1
II Recommendations , 2
III Introduction 3
IV Dyeing Systems 9
V Characterization of Dyeing Wastewaters 39
VI Biological Treatment 46
VII Physical Chemical Treatment: Coagulation,
Adsorption, Ozonation 100
VIII Discussion of Treatability Results 204
IX Textile Mill Effluent Survey 228
X Compendium 240
XI Appendices
A. Procedures for Trace Metals Analysis 274
B. Procedures for Benzidine Analysis 280
C. Biodegradability Procedure 285
D. Characteristics of Powdered Activated
Carbons Tested 288
E. Sample Calculation for Determination of
Ozone Content' of Feed Gas 290
111
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FIGURES
Number
1 Textile processing flow chart—fiber/fabric, all
classes, natural and synthetic 5
2 Experimental design for biological study 48
3 Dyeing wastewater No. 1: biodegradation 61
4 Dyeing was tewater No. 2: biodegradation 61
5 Dyeing was tewater No. 3: biodegradation 64
6 Dyeing was tewater No. 4: biodegradation 64
7 Dyeing wastewater No. 5: biodegradation 68
8 Dyeing wastewater No. 6: biodegradation 68
9 Dyeing wastewater No. 7: biodegradation 71
10 Dyeing wastewater No. 8: biodegradation 71
11 Dyeing wastewater No. 9: biodegradation 76
12 Dyeing wastewater No. 10: biodegradation 76
13 Dyeine wastewater No. 11: biodegradation 80
14 Dyeing wastewater No. 12: biodegradation 80
15 Dyeing wastewater No. 13; biodegradation 83
16 Dyeing wastewater No. 14; biodegradation 83
17 Dyeing wastewater No. 15: biodegradation 87
18 Dyeing wastewater No. 16: biodegradation 87
19 Dyeing wastewater No. 17: biodegradation 91
20 Dyeing wastewater No. 18: biodegradation 94
21 Dyeing wastewater No. 19: biodegradation 96
22 Dyeing wastewater No. 20: biodegradation 96
23 Schematic diagram of apparatus for ozonation study 103
24 Dyeing wastewater No. 1: decolorization by lime and
alum coagulation 105
iv
-------
Figures (con.)
Number
25 Dyeing wastewater No. 1: total organic carbon reduc-
tion by lime and alum coagulation 106
26 Dyeing wastewater No. 2: decolorization by lime and
powdered activated carbon adsorption 107
27 Dyeing wastewater No. 2: removal of total organic
carbon by powdered activated carbon 108
28 Dyeing wastewater No. 2: decolorization by ozone 110
29 Dyeing wastewater No. 3: decolorization by alum and
iron (HI) coagulation 111
30 Dyeing wastewater No. 3: decolorization by ozone 113
31 Dyeing wastewater No. 4: color removal by lime and
alum coagulation 115
32 Dyeing wastewater No. 4: removal of total organic
carbon by lime and alum coagulation 116
33 Dyeing wastewater No. 4: decolorization by ozone 117
34 Dyeing wastewater No. 5: color and total organic
carbon removal by alum 119
35 Dyeing wastewater No. 5: decolorization by powdered
activated carbon adsorption 120
36 Dyeing wastewater No. 5: total organic carbon removal
by powdered activated carbon 121
37 Dyeing wastewater No. 5: decolorization by ozone 122
38 Dyeing wastewater No. 6: color removal by lime and
alum coagulation 123
39 Dyeing wastewater No. 6: color and total organic
removal by powdered activated carbon 125
40 Dyeing wastewater No. 7: decolorization by powdered
activated carbon 126
41 Dyeing wastewater No. 7: removal of color by acidifi-
cation, iron (II) reduction, neutralization 128
42 Dyeing wastewater No. 7: total organic carbon removal
by acidification, iron (II) addition, neutralization 129
43 Dyeing wastewater No. 8: decolorization by powdered
activated carbon 130
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Figures (con.)
Number
44 Dyeing wastewater No. 8: total organic carbon removal
by powdered activated carbon 133
45 Dyeing wastewater No. 8: decolorization by ozone 134
46 Dyeing wastewater No. 9: color removal by lime and
alum coagulation 136
47 Dyeing wastewater No. 9: removal of total organic carbon
by lime, alum, and powdered activated carbon 137
48 Dyeing wastewater No. 9: decolorization by ozone 138
49 Dyeing wastewater No. 10: color and total organic carbon
removal by alum coagulation 140
50 Dyeing wastewater No. 10: decolorization by powdered
activated carbon 142
51 Dyeing wastewater No. 10: removal of total organic carbon
by powdered activated carbon 143
52 Dyeing wastewater No. 10: decolorization by ozone 145
53 DyeingwastewaterNo.il: decolorization by alum coagu-
lation alone and by two-stage sequence involving alum
coagulation and powdered activated carbon 146
54 Dyeing wastewater No. 11: removal of total organic carbon
by alum coagulation or powdered activated carbon
adsorption 147
55 Dyeing wastewater No. 11: decolorization by ozone 148
56 Dyeing wastewater No. 12: color removal by alum coagu-
lation alone and by two-stage sequence involving alum
coagulation and powdered activated carbon adsorption 150
57 Dyeing wastewater No. 12: decolorization by lime 151
58 Dyeing wastewater No. 12: effect of pH on decolorization
by ozone 153
59 Dyeing wastewater No. 12; effect of ozone partial pres-
sure on decolorization 153
60 Dyeing wastewater No. 13: color removal by powdered
activated carbon adsorption 155
61 Dyeing wastewater No. 13: removal of total organic carbon
by powdered activated carbon 157
vi
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Figures (con.)
Number
62 Dyeing wastewater No. 13: effect of pH on decolorization
by ozone 158
63 Dyeing wastewater No. 13: effect of ozone partial pres-
sure on decolorization 158
64 Dyeing wastewater No. 13: efficiency of ozone adsorption
and utilization 161
65 Dyeing wastewater No. 14: decolorization by alum coagu-
lation alone and by two-stage sequence involving alum
coagulation and powdered activated carbon adsorption 162
66 Dyeing wastewater No. 14: color and total organic carbon
removal by powdered activated carbon alone 163
67 Dyeing wastewater No. 14: removal of total organic carbon
by alum coagulation alone and by two-stage sequence invol-
ving alum coagulation and powdered activated carbon
absorption 165
68 Dyeing wastewater No. 14: decolorization by ozone 166
69 Dyeing wastewater No. 15: color removal by lime, alum,
and iron (HI) coagulation 167
70 Dyeing wastewater No. 15: decolorization by ozone 168
71 Dyeing wastewater No. 16: decolorization by powdered
activated carbon 170
72 Dyeing wastewater No. 16: removal of total organic carbon
by powdered activated carbon 172
73 Dyeing wastewater No. 16: decolorization by ozone 173
74 Dyeing wastewater No. 17: color removal by alum
coagulation 174
75 Dyeing wastewater No. 17: color and total organic carbon
removal by powdered activated carbon 176
76 Dyeing wastewater No. 17: decolorization by ozone 177
77 Dyeing wastewater No. 18: decolorization by powdered
activated carbon 179
78 Dyeing wastewater No. 18: removal of total organic carbon
by powdered activated carbon adsorption 181
79 Dyeing wastewater No. 18: decolorization by ozone 182
vii
-------
Figures (con.)
Number
80 Dyeing wastewater No. 19: color removal by alum
coagulation 183
81 Dyeing wastewater No. 19: decolorization by ozone 185
82 Dyeing wastewater No. 20: color removal by powdered
activated carbon absorption 186
83 Dyeing wastewater No. 20: removal of total organic carbon
by powdered activated carbon 187
84 Dyeing wastewater No. 20: decolorization by ozone 189
85 Colored photograph showing effect of different treatments
on the appearance of representative dyeing wastewater 196
86 Comparison of reactive and basic dyeing wastewaters with
respect to decolorization by powdered activated carbon 217
87 Adsorption of color from reactive and basic dyeing waste-
waters in accordance with Langmuir adsorption mo'del 219
88 Comparison of reactive and disperse dyeing wastewaters
with respect to decolorization by ozone 220
89 Comparison of direct and basic dyeing wastewaters with
respect to decolorization by ozone 221
90 Dye jig 244
91 Dye beck 244
92 Skein dyeing machine 245
93 Package machine 245
94 Package dyeing 246
95 Beam dyeing 246
96 Beam dyeing (fabric) 247
97 Hosiery dyeing 247
98 Jet dyeing machine 248
99 Padder (two types) 248
100 Pad-roll machine 250
101 Pad-steam range 250
102 Thermosol, pad-steam range 252
viii
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Figures (con.)
Number
103 Carpet dyeing range
104 Indigo dyeing range
Bl Spectrophotometer curve of benzidine oxidized with
chloramine T and extracted with ethyl acetate 282
ix
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TABLES
Number Page
1 Dyes Used in Dyeing Procedures 11
2 Auxiliaries Used in Dyeing Procedures 13
3 Analytical Procedures 40
4 Analysis of Dyeing Systems Wastes 41
5 Raw Wastewater Characteristics 42
6 Effect of Biological Treatment on BOD, TOG, and
Color Removal: 100% Dilution 49
7 Effect of Biological Treatment on BOD, TOG, and
Color Removal: 10% Dilution 52
8 Effect of Biological Treatment on BOD, TOG, and
Color Removal: 1% Dilution 53
9 Effect of Dyeing Wastewaters on Nitrification 56
10 Biological Treatability of Wastewater No. 1 59
11 Effect of Wastewater No. 1 on Nitrification 59
12 Biological Treatability of Wastewater No. 2 62
13 Effect of Wastewater No. 2 on Nitrification 62
14 Biological Treatability of Wastewater No. 3 63
15 Effect of Wastewater No. 3 on Nitrification 63
16 Biological Treatability of Wastewater No. 4 66
17 Effect of Wastewater No. 4 on Nitrification 66
18 Biological Treatability of Wastewater No. 5 67
19 Effect of Wastewater No. 5 on Nitrification 67
20 Biological Treatability of Wastewater No. 6 70
21 Effect of Wastewater No. 6 on Nitrification 70
22 Biological Treatability of Wastewater No. 7 72
23 Effect of Wastewater No. 7 on Nitrification 72
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Tables (con.)
Number Page
24 Biological Treatability of Wastewater No. 8 74
25 Effect of Wastewater No. 8 on Nitrification 74
26 Biological Treatability of Wastewater No. 9 75
27 Effect of Wastewater No. 9 on Nitrification 75
28 Biological Treatability of Wastewater No. 10 77
29 Effect of Wastewater No. 10 on Nitrification 77
30 Biological Treatability of Wastewater No. 11 79
31 Effect of Wastewater No. 11 on Nitrification 79
32 Biological Treatability of Wastewater No. 12 81
33 Effect of Wastewater No. 12 on Nitrification 81
34 Biological Treatability of Wastewater No. 13 82
35 Effect of Wastewater No. 13 on Nitrification 82
36 Biological Treatability of Wastewater No. 14 85
37 Effect of Wastewater No. 14 on Nitrification 85
38 Biological Treatability of Wastewater No. 15 86
39 Effect of Wastewater No. 15 on Nitrification 86
40 Biological Treatability of Wastewater No. 16 89
41 Effect of Wastewater No. 16 on Nitrification 89
42 Biological Treatability of Wastewater No. 17 90
43 Effect of Wastewater No. 17 on Nitrification 90
44 Biological Treatability of Wastewater No. 18 93
45 Effect of Wastewater No. 18 on Nitrification 93
46 Biological Treatability of Wastewater No. 19 95
47 Effect of Wastewater No. 19 on Nitrification 95
48 Biological Treatability of Wastewater No. 20 97
49 Effect of Wastewater No. 20 on Nitrification 97
50 Effect of pH on Coagulation of Dyeing Wastewater No. 3 by
Alum and Ferric Chloride 112
XI
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Tables (con.)
Number Page
51 Effect of Iron (II) Reduction on Dyeing Wastewater No. 7 131
52 Effect of pH on Treatment of Dyeing Wastewater No. 8 by
Powdered Activated Carbon 132
53 Effect of Different Types of Powdered Activated Carbons
on Treatment of Dyeing Wastewater No. 8 at pH 4. 5 132
54 Effect of pH on Treatment of Dyeing Wastewater No. 10
by Powdered Activated Carbon 141
55 Effect of Different Types of Powdered Activated Carbons
on Treatment of Dyeing Wastewater No. 10 at pH 5.1 141
56 Effect of Alum and Powdered Activated Carbon on Treat-
ment of Dyeing Wastewater No. 11 149
57 Effect of Alum and Powdered Activated Carbon on Treat-
ment of Wastewater No. 12 152
58 Effect of Different Types of Powdered Activated Carbons
on Treatment of Dyeing Wastewater No. 13 156
59 Effect of pH on Treatment of Dyeing Wastewater No. 13
by Powdered Activated Carbon 156
60 Efficiency of Ozone Absorption During Decolorization of
Dyeing Wastewater No. 13 160
61 Effect of Different Types of Powdered Activated Carbons
on Treatment of Dyeing Wastewater No. 16 171
62 Effect of pH on Treatment of Dyeing Wastewater No. 16
by Powdered Activated Carbon 171
63 Effect of Different Types of Powdered Activated Carbons
on Treatment of Dyeing Wastewater No. 18 178
64 Effect of pH on Treatment of Dyeing Wastewater No. 18 by
Powdered Activated Carbon 178
65 Effect of Different Types of Powdered Activated Carbons
on Treatment of Dyeing Wastewater No. 20 188
66 Summary of Physical-Chemical Treatability Studies 190
67 Legend for Figure 85 197
68 Effect of Biological Treatment on BOD, TOG, and Color
Removal from Dyeing Wastewaters 205
xii
-------
Tables (con.)
Number Page
69 Effect of Dyeing Wastewaters on Nitrification 206
70 Effect of Biological Treatment on BODs/TOC Ratios in
Dyeing Wastewaters with Acclimated Seed 208
71 Coagulation and Adsorption: Best Means of Decolorization
by Dye Class 211
72 Requisite Alum Dosages for Best Degree of Decolor ization
and Corresponding Removals of Total Organic Carbon 213
73 Requisite Powdered Activated Carbon Dosages for Best
Degree of Decolorization and Corresponding Removals
of Total Organic Carbon 216
74 Summary: Decolorization by Ozone 223
75 Results of Combined Biological/Physical-Chemical
Treatment 225
76 Survey of Dyeing Wastes from Textile Mills, Cadmium 232
77 Survey of Dyeing Wastes from Textile Mills, Chromium 233
78 Survey of Dyeing Wastes from Textile Mills, Copper 234
79 Survey of Dyeing Wastes from Textile Mills, Lead 235
80 Survey of Dyeing Wastes from Textile Mills , Mercury 236
81 Survey of Dyeing Wastes from Textile Mills , Zinc 237
82 Survey of Dyeing Wastes from Textile Mills , Benzidine 238
83 Classification of Dyes by Usage and Chemical Nature 258
Al Comparison of Digestion Procedure 275
A2 Analysis of Unspiked Dyebath Liquor No. 1 276
A3 Analysis of Spiked Dyebath Liquor No. 1 276
A4 Analysis of Spiked Distilled Water 277
A5 Accuracy and Precision 278
A6 Determination of Mercury in NBS Standard No. 1642 278
A7 Stability of Samples 279
Bl Procedure for the Determination of Benzidine in Textile
Mill Dye Bath Exhaust Liquors 281
Dl Characteristics of Powdered Activated Carbons Tested 289
xiii
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LIST OF ABBREVIATIONS AND SYMBOLS
ABBREVIATIONS
ADMI
APHA
AWWA
BOD and
C.I. Name
COD
EPA
FWPCA
g
g/i
N.B.S.
NH3-N
nm
NO -N
NO^-N
NO,/NO_-N
PAC J
Pt-Co
Scfh
S.D.
TKN
TOC
UNC
WPCF
ym
-American Dye Manufacturers Institute
-American Public Health Association
-American Water Works Association
-five day biochemical oxygen demand
-Color Index generic name
-chemical oxygen demand
-United States Environmental Protection
Agency
-Federal Water Pollution Control Act
-gram
-grams per liter
-National Bureau of Standards
-ammonia nitrogen
-nano meter
-nitrite nitrogen
-nitrate nitrogen
-nitrite-nitrate nitrogen
-powdered activated carbon
-platinum cobalt color standard
-standard cubic feet per hour
-standard deviation
-total kjeldahl nitrogen
-total organic carbon
-University of North Carolina at
Chapel Hill
-Water Pollution Control Federation
-micrograms per liter
-micrometer
SYNBOLS
-approximately
-less than
-more than
-less than or equal to
-more than or equal to
-approximately equal to
XIV
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ACKNOWLEDGMENTS
The financial support of Cotton Incorporated, The Carpet
and Rug Institute and the Northern Textile Association is
acknowledged with sincere appreciation. Assistance was
provided by Mr. Robbie Stone of Cotton Incorporated,
Mr. Piet Bodenhorst of The Carpet and Rug Institute and
Mr. Paul Weise of the Northern Textile Association.
The American Textile Manufacturers Institute assisted by
providing for the collection of mill samples for the metals
content survey. Mr. O'Jay Niles, Executive Director of the
American Textile Manufacturers Institute provided valuable
assistance.
The dyeings required for the study were performed at North
Carolina State University under the direction of Mr. Gene
Floyd. The fabric, dyes and chemicals used were supplied
by the members of the American Textile Manufacturers Ins-
titute and the American Dye Manufacturers Institute.
The treatability studies were performed at the University
of North Carolina at Chapel Hill under the direction of
Dr. Philip C. Singer and Dr. Linda W. Little.
The analyses of the mill samples were performed in the
laboratories of several members of the American Dye Manu-
facturers Institute. Coordination of the analytical effort
and the preparation of the summary were under the direction
of Dr. Harshad Vyas of Verona Division of Mobay Chemical
Corporation. Individuals assisting in this effort include
Mr. Thomas Alspaugh of Cone Mills, Mr. William Martin of
Martin Marietta Chemicals, Mr. James Gouch of Allied Chem-
ical Corporation, Dr. J. Robert Martin of E. I. duPont de
Nemours and Company, Inc., Mr. John Murphy of ICI America,
Mr. Roger Rounds of GAP Corporation and Dr. Janos Schultze
of Ciba-Geigy Corporation.
Preparation of the compendium of dyeing methods and auxil-
iary chemicals was by Dr. K. Campbell of North Carolina
State University with the assistance of Dr. Samuel N. Boyd
of E.' I. duPont de Nemours and Company, Inc., and Mr. Norman
Anderson (now deceased) of Ciba-Geigy Company. Assistance
was provided by William L. Acree of Burlington Industries,
Clude B. Anderson of Verona Division of Mobay Chemical
Corporation, J. V. Isharani of Ciba-Geigy Corporation 'and
Dr. R. J. Thomas of E. I. duPont de Nemours and Company,
Inc. Valued guidance throughout the project was provided
by Thomas N. Sargent, E. P. A. Project Officer.
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Page 2 - Acknowledgments
Overall coordination of the project was provided by
Dr. Roderick H. Horning of Crompton & Knowles Corporation
in his capacity as Grant Director.
General assistance was provided by the members of the
American Dye Manufacturers Institute's Ecology Steering
Committee. Those not mentioned elsewhere in the acknowledg-
ments include Mr. Max Saltzman representing Allied Chemical
Company, Mr. Dave Schwartzberg of GAP Corporation, Mr.
William Kraemer of BASF and Mr. Francis Robertaccio of
E. I. duPont de Nemours Company, Inc.
xvi
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SECTION I
INTRODUCTION
BACKGROUND
In 1970, the American Dye Manufacturers Institute undertook
a program to meet an increasing need for information con-
cerning dyes in the environment. This effort took the form
of both "in-house" work and study grants to several univer-
sities. The "in-house" work produced a study of the heavy
metal contents of dyes and an improved method for the
measurement of color in solutions. The work at the univer-
sities included studies of the effects of 46 dyes on aerobic
and anaerobic systems and on fish. All of this work was.^
published by ADMI in Dyes and the Environment, Volume 3^,
(September 1973) .
This work was continued with a grant which provided for a
study of the effects of an additional ten dyes2on fish, and
a study of the effects of all 56 dyes on algae . The 9 dyes
most likely to be a burden on the environment were studied
in pilot plant secondary treatment systems in order to
ascertain both the effect of the dye on the treatment system
and the effect of the treatment on the dye. Effluent from 2
these pilot plant systems was studied for its effect on fish .
A Masters thesis which examines the effects on fish and algae2
of a variety of anthraquinone dyes is included with this work .
These studies were published by ADMI in Dyes and the Environ-
ment, Volume II, (September 1974) .
THE PRESENT WORK
This report documents a continuation of these earlier studies.
It examines the treatability of twenty selected wastewaters
from dye baths and extends the study of heavy metals in dyes
to a survey of the heavy metal content of the wastewater from
commercial dye baths. A compendium is included as an aid to
those not familiar with the art of dyeing and to provide a
reference to the many varieties of additives commonly used
in dye baths. The report is rich in raw experimental data
in order that it might prove valuable to users. The variety
and complexity of commercial dyeing practice is such that it
is more appropriate to present detailed data than to generalize
the data and limit its usefulness. A primary objective of the
study is to provide a preliminary assessment of which treatment
methods might be most useful for each of the various wastewaters
examined.
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THE DYEING SYSTEMS
The parameters of greatest significance in providing real
variety to dyeing systems are the fiber dyed, the applica-
tion class of the dye used and the application method.
The twenty dyeing systems were selected so as to provide
a broad representation of actual practice in dyeing and to
include as much variation of the three significant para-
meters as possible. Fibers represented in the twenty
systems include cotton, rayon, wool, polyamide, polyester
and polyacrylic. Yarn, woven, knit and carpet constructions
are represented. The application classes of dyes used are
acid, basic, direct, reactive, vat, disperse, sulfur, naph-
thol, direct developed, 1:2 and 1:4 acid premetallized, acid
chrome and after copperable direct. Application methods
include: beck, package machine, continuous range and Kuester
range.
The dyeings, except for the Kuester application, were all
accomplished in pilot scale equipment at North Carolina
State University. This provided the means to exercise
good control over the variables and to simulate commercial
practice. The Kuester application was accomplished in the
laboratory of an ADMI member, also on a pilot scale.
Wastewaters from the dye baths were transported to the
University of North Carolina at Chapel Hill for characteri-
zation and treatability studies. Additional samples were
provided to ADMI for heavy metals and benzidine analyses.
BIOLOGICAL TREATABILITY
Biological systems are in common use throughout the textile
industry and many wastewaters from this industry have been
shown to be treatable by this method. The present study
examines the treatability of wastewaters from only the
dye bath, in order to provide insight into the impact of
an individual dye bath on the biological system and to
examine the efficiency of the application of biological
treatment. In practice, wastewaters from dye baths are
diluted appreciably with other process wastes and rinse
waters.
The wastewaters were treated at full strength and in two
dilutions in systems using seed from a combined domestic/
industrial waste activated sludge plant and acclimated seed.
A control with Hg(II) added was used to distinguish between
biological and nonbiological changes. The treatment was
carried on for 21 days and samples were periodically removed
for examination.
-------
PHYSICAL TREATMENT SYSTEMS
Alternative techniques to biological treatment that may be
applicable to wastewater from dye baths include coagulation
or precipitation, carbon adsorption and oxidation. Coagu-
lants used included lime, aluminum salts and ferric salts.
Various types of powdered activated carbon were used.
Oxidation investigations were limited to ozonation.
Standard jar test procedures were used to evaluate the
treatability of the wastewaters with the coagulants and
with carbon. Ozonation was accomplished by passing oxygen
through an ozone generator and treating the samples in a
gas-liquid contactor at a controlled gas flow rate. The
ozone content of the applied gas stream was measured analy-
tically to determine the application rate. All of the
physical-chemical studies were performed at full strength
of the wastewater. Combined biological and selected
physical-chemical treatment was examined for three of the
wastewaters.
TEXTILE MILL EFFLUENT SURVEY
Earlier work by ADMI showed that the heavy metal content
of non-metallized dyes was less than 100 ppm. The objective
of this study is to evaluate the contribution of heavy metals
to textile mill effluents from the dyeing operation.
This was accomplished by sampling dye bath wastewaters from
selected mill dyeing operations and analyzing them for
cadmium, chromium, copper, lead, mercury and zinc.
Benzidine has been a recent cause for concern. For this
reason, analyses for benzidine were run on these same samples
to provide a preliminary assessment of benzidine concentrations
over a wide range of wastewaters from dyeing operations.
THE COMPENDIUM
The compendium included in this report provides a convenient
reference to commercial dyeing techniques for those not
familiar with this art. Included in the compendium is a
tabulation classifying common additives to dye baths according
to chemical type. This is intended as a resource that can be
used along with the description of the dyeing systems in
Section IV to gain some insight into the chemicals likely to
be present in dye baths. This tabulation is not intended to
be exhaustive but is rather an illustrative supplement to
Section IV.
-------
Table I is a flow chart-depicting many of the processing
steps through which fibers or fabrics may pass in preparing
them for various end uses. The particular processing step
of concern in this study is marked. Most of the additional
steps noted on the chart also produce waste effluent and
consideration of the total effluent from textile processing
operations must necessarily account for these steps. While
every textile mill does not utilize every processing step
indicated, most use a number of them, thus contributing to
the complexity of treating textile mill effluent.
THE APPENDICES
Information relative to the analytical protocols used in
this study have been included in the appendices.
-------
FIGURE 1. TEXTILE PROCESSING FLOW CHART
FIBER/FABRIC, ALL CLASSES, NATURAL & SYNTHETIC
TEXTILE PREPARATION
1
SINGEING
SCOURING
»
BLEACHING
1
CARBONIZING
1
MERCERIZING
DBS IZ ING
I
COLORING
1
WHITENING
1
PRINTING
DYEING
1
/AREA OF^N
\THIS STUDY/
4^""^
FINISHING
1
DURABLE
PRESS
1
ANT I
SLIP ING
1
HOME
FURNISHING
1
WATER
PROOFING
FLAME
RETARD ANT
1
ATMOSPHERIC
FADING
PROTECTION
1 1
SOIL
RELEASE &
REPELLANT
FULLING
1 1
SOFTENING
HAND
MODIFIER
ANTISTATS
1
END
1
APPAREL
USE
1 1
INDUSTRIAL
AUTOMOTIVE
FABRIC
KNITWEAR
-------
REFERENCES
1. ADMI. Dyes and the Environment: Reports of Selected
Dyes and Their Effects, Volume I., American Dye
Manufacturers Institute. September 1973.
2. ADMI. Dyes and the Environment: Reports of Selected
Dyes and Their Effects, Volume II., American Dye
Manufacturers Institute. September 1974.
-------
SECTION II
CONCLUSIONS
1. Dyeing wastewaters can be effectively treated with
respect to BOD, TOC, and color removal if they can
be segregated in-plant.
2. No one specific type of treatment will suffice for all
dyeing wastewaters; the most effective type of treatment
depends upon the type of dyeing performed and the
chemical composition of the dye bath.
3. Disperse, vat, and sulfur dyeing wastewaters can be
readily decolorized by coagulation with alum but are
not readily decolorized by activated carbon.
4. Reactive, basic, acid, and azoic dyeing wastewaters
can be readily decolorized by activated carbon; basic
dyes are more strongly adsorbed on carbon than reactive
dyes.
5. Reactive dyes can be decolorized most effectively by
ozone; disperse dyes are decolorized least by ozone.
6. BOD and TOC removal by physical-chemical treatment
techniques, i.e., coagulation, carbon adsorption, and
ozonation, is not very effective.
7. The organic constituents of the dyeing wastewaters are
relatively biodegradable and BOD and TOC can be
effectively reduced by biological treatment.
8. BOD removal is, generally, not inhibited by the dye
molecules or other components of the dye bath.
9. Color, in general, is not readily removed by biological
waste treatment, suggesting that the dye molecules are
not readily biodegradable.
10. Some dyeing wastewaters are capable of inhibiting
biological nitrification, but the causative agents of
the inhibitory action have not been identified.
11. Dyeing wastewaters can be effectively treated with respect
to BOD, TOC, and color removal by coupling biological
treatment with physical-chemical treatment methods, the
former to remove BOD and TOC and the latter to remove color
12. The heavy metal content of exhausted dye baths is low
except in those cases where a heavy metal is used for
oxidation (e.g. Chromium) or for after treatment (e.g.
Copper).
13. Dyeing wastewaters generally contain low suspended
solids.
-------
SECTION III
RECOMMENDATIONS
Among the different application classes of dyes inves-
tigated, disperse, vat and sulfur dyes have been shown
to be readily removed from dyeing wastewaters by coag-
ulation; basic, acid, azoic, and reactive dyes are
readily removed by activated carbon adsorption; reactive
dyes are more easily decolorized by ozone than are dis-
perse dyes. Laboratory-scale studies should be continued
to determine which chemical classes among the different
application classes of dyes are most effectively removed
by these physical-chemical treatment techniques, e.g.
among the basic dyes, which chemical classes (azo,
anthraquinone, thiazole, indophenol, etc.) are most
strongly adsorbed on activated carbon. This could pro-
vide a useful criterion for selection of dyes in commer-
cial applications.
This study has shown, on a bench-scale batch basis only,
that dyeing wastewaters can be effectively treated for
the removal of BOD, TOC, and color. The results of this
study should be applied on a continuous-flow pilot-scale
basis in order to confirm the conclusions regarding the
best type of treatment, to establish design and opera-
tional criteria (e.g. mixing requirements for floccula-
tion basins, overflow rates for settling tanks, loadings
and contact times for carbon columns, etc.) for most
efficient treatment, and to develop cost information to
achieve desired levels of performance.
Modifications of dyeing procedures should be investigated
to select methods and system components which provide
more effective adsorption of the dyes by the substrate
and which minimize the concentrations of potential pollu-
tants in the effluent from the dye bath, e.g. kjeldahl-
nitrogen, BOD and TOC, dissolved solids, etc.
-------
SECTION IV
DYEING SYSTEMS
This project is designed to provide a meaningful preliminary
measure of the contribution of commercial textile dyeing
operations to the pollution burden of dyeing and finishing
plants, and to evaluate a variety of waste-treatment pro-
cedures for removal of the many different pollutants.
Textile dyeing technology, in the broad sense, is multi-
dimensional and extremely complex. Many fiber substrates,
several types of process equipment, hundreds of chemically
different dyes, and a large number of dye bath auxiliary
chemicals are used routinely. The evolution of textile
dyeing from an "art" to modern processes subject to precise
engineering, and even computer control, has been in process
for a very few years and is not yet complete. It was
necessary, therefore, to select very carefully the dyeing
systems to be used in this study to insure that the small
number of samples permitted by available time and funding
would yield the maximum amount of information which would
be truly representative of commercial practice.
The twenty dyeing systems described later in this chapter
were defined by a panel of five men representing many
decades of practical experience in dye and textile dyeing
technology. These systems reflect all the major fiber
substrates, representative dye types (from the standpoint
of both chemical types and application classes), and major
dye bath auxiliary types. While pilot plant equipment used
in the actual dyeing experiments does not provide scale-down
models of all major dyeing equipment, this should not sig-
nificantly affect the representative character of the dye
bath wastes.
Fibers utilized include cotton, rayon, wool, polyamide
(including three chemical variants receptive to different
dye classes), polyacrylic, and one intimate blend of cotton
and polyester. Different fibers were processed as yarn,
woven fabric, knit fabric and tufted carpet. Thirty-seven
dyes included representatives of direct, after coppered
direct, developed direct, acid, 1:2 and 1:1 metallized acid,
vat, reactive, naphthol, sulfur, disperse and basic classes.
Representative dyeing processes included both batch and
continuous operations.
Dyeing experiments were carried out in pilot plant equipment
under close supervision of Mr. Gene G. Floyd, North Carolina
State University, Raleigh, N. C. Combined residual dye bath,
scour and rinse water from individual batch processes, and
-------
combined scour and rinse water from individual continuous
processes were conveyed without delay to University of
North Carolina at Chapel Hill, N. C., for wastewater treat-
ability studies under direction of Drs. Philip C. Singer,
and Linda W. Little. Samples of these effluents also were
submitted to selected industry laboratories (ADMI member
companies) for spectral characterization and determination
of benzidine and selected heavy metals.
Procedures used in the selected dyeing operations are
detailed in the following section. Unless otherwise
specified, percentages given are based on the weight of
fiber. Additional information on dye bath auxiliaries
and specific dyes employed follow the dyeing procedures is
shown in Tables 1 and 2. The sequence of dyeing processes
investigated is arbitrary and is numbered in the actual
sequence.
10
-------
Table 1. DYES USED IN DYEING PROCEDURES
Application class
C. I. name
Acid
Basic
Developer
Disperse
Fiber Reactive
Insoluble Azo
Mordant Acid
Naphthol
Sulfur
Acid Black 52
Acid Blue 7
Acid Blue 40
Acid Blue 122
Acid Blue 298
Acid Red 145
Ac id Red
Acid Yellow 198
Basic Blue 92
Basic Blue 41
Basic Red 23
Basic Red 73
Basic Yellow 11
Basic Yellow 31
Developer 1
Direct Black 38
Direct Blue 160
Disperse
Disperse
Disperse
Disperse
Disperse
Disperse
Disperse
Disperse
Disperse
Blue 56
Blue 62
Blue 87
Brown 2
Orange 41
Red 55
Violet 28
Yellow 3
Yellow 42
Reactive Red 40
Reactive Red 120
Azoic Diazo
Component 13
Acid Black 11
Azoic Coupling
Component 7
Sulfur Black 1
11
-------
Table 1 (continued). DYES USED IN DYEING PROCEDURES
Application class
C. I. name
Vat
Vat Black 13
Vat Black 25
Vat Blue 18
Vat Green 3
Vat Orange 2
12
-------
Table 2. AUXILIARIES USED IN DYEING PROCEDURES
Commercial name
Use
Chemical nature
Alkanol A-CN
Alkanol ND
Alkanol WXN
Aritex AD
Avitone T
Barisol BRM
Calgon
Capracyl
Leveling Salt
Carolid FLM
Carolid 3F
Chemocarrier
KD5W
Compound 8S
Duponol FAS
Irgaformal S2E
Levegal KN
nonionic surfactant
anionic surfactant
anionic surfactant
anionic surfactant
anionic surfactant
anionic surfactant
Water softener
nonionic surfactant
carrier
carrier
carrier
anionic surfactant
foaming agent
antiform agent
leveling agent
ethylene oxide
condensate
sodium aryl
sulfonate
modified sodium
alkylaryl sulfonate
sodium long-chain
alcohol sulfate
sodium hydrocarbon
sulfonate
phosphated long-
chain alcohol
NaPO-
ethylene oxide
condensate
emulsified ortho-
phenylphenol
nonionic, modified
biphenyl derivative
self emulsifiable
solvent, nonionic
complex diaryl
sulfonate
anionic surfactant
composition
blend of hydro-
carbons, terpens,
silicone, emulsifier
oxethylated fatty
acid derivative
13
-------
Table 2 (continued). AUXILIARIES USED IN DYEING PROCEDURES
Commercial name
Use
Chemical nature
Ludigol
Merpol DA
Merpol HCS
Merpol ST
Mesitol NBS
Orvus K Paste
Product BCO
Retarder HP
Sequestrene ST
Sodyefide B
Syngum D-47-D
Superclear 100N
Tanalon Jet
Versene
anti-reducing
agent
nonionic surfactant
nonionic surfactant
nonionic surfactant
after treating agent
anionic surfactant
amphoteric sur-
factant
retarder for
cationic dyes
sequestrant for
calcium, copper,
iron
liquid reducing
agent
thickener for
carpet dyeing
thickener
carrier for pres-
sure dyeing polyes-
ter
sequestrant
sodium m-nitrobenzene
sulfonate
ethylene oxide
condensate
ethylene oxide
condensate
ethylene oxide
condensate
long-chain alcohol
sulfate
cetyl betaine
cationic compound
tetrasodium salt
of sequestrene AA
Na-S and Na S in
solution
natural gum
derivative
natural gum
modified self-
emulsifiable
solvents
EDTA
14
-------
DYEING PROCEDURE NO. 1
DYES:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE:
Rinse:
Oxidize:
Vat
Package Dyeing - Exhaust
Gaston County - 35 pound
package dyeing machine
15 one-pound packages
Mercerized cotton yarn
15:1
Set bath at 100° F. with:
2.0% Compound 8-S
10.0% Caustic soda
5.0% C.I. Vat Blue 18
3.5% C.I. Vat Black 13
1.0% C.I. Vat Orange 2
Circulate five minutes
Raise temperature 3° F. per
minute to 180° F. Continue
to circulate bath for 20
minutes (cycle machine 4
minutes inside-out; 4 minutes
outside-in)
Cool bath to 140° F. and add:
10.0% sodium hydrosulfite (1/2
inside-out; 1/2 outside-in)
Circulate for 30 minutes re-
versing cycle each 4 minutes.
Drop bath
Give two cold rinses - (original
volume)
Set bath at 110° F. with 1.0%
acetic acid (56%)
Circulate 5 minutes, add:
2.0% sodium perborate
Raise bath to 140° F.
Run 10 minutes
Raise bath to 190° F.
15
-------
Soaping: 1.0% Avitex AD (surfactant)
0.5% tetrasodium pyrophosphate
Run 10 minutes at 190° F.
Drop bath
Rinse: Give two cold rinses (original
volume)
Extract: Hydro Extractor
Dry: Oven
16
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DYES:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE:
Rinse:
Dry:
DYEING PROCEDURE NO. 2
Acid - 1:2 metal - complex
Exhaust
Rodney Hunt - 20" Sample Dye Beck
Polyamide Tricot
30:1
Set bath at 100° F.. with the following:
1.0% Capracyl leveling salt (non-
ionic surfactant)
4.0% ammonium acetate
5.0% sodium sulfate
20.% C.I. Acid Black 52
Bath pH 6.5
Circulate fabric for 10 minutes
at 100° F.
Raise temperature in 45 minutes
to 205° F.
Run at 205° F. for 60 minutes
Cool to 140° F.
Give one cold rinse (original
volume)
Clip Tenter Frame
17
-------
DYES:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE:
Rinse:
Scour:
Rinse:
Dry:
DYEING PROCEDURE NO. 3
Disperse
Atmospheric Exhaust
Rodney Hunt - 20" Sample Dye Beck
Polyester texturized double knit
30:1
Set bath at 120° F. with:
l.Og/1 Compound 8-S (surfactant)
5.0g/l Carolid FLM (ortho-phenyl-
phenol carrier)
1.0% acetic acid (56%) to pH of 5.4
3.0% C.I. Disperse Blue 87
1.0% C.I. Disperse Yellow 42
l.Og/1 Compound 8-S (surfactant)
Raise temperature of bath to 212° F.
in 40 minutes
Dye at 212° F. for 90 minutes
Cool to 160° F.
Drop bath
Give one rinse (original volume)
Scour at 160° F. for 10 minutes with:
l.Og/1 Merpol HCS (surfactant)
l.Og/1 soda ash
l.Og/1 sodium hydrosulfite
Drop bath
Rinse at 160° F. (original volume)
Rinse at 120° F. (original volume)
Clio Tenter Frame
18
-------
DYES:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE:
Rinse:
After Treatment:
Rinse:
Dry:
DYEING PROCEDURE NO. 4
After-copperable direct
Exhaust
Rodney Hunt 20" Sample Dye Beck
Bleached mercerized cotton
30:1
Add to bath:
0.5 g/1 soda ash (pH 8.5)
0.5% Barisol BRM (anionic surfactant)
0.5% Calgon (sequestrant)
Circulate for 10 minutes at 120° F.
and add dye
4.0% C.I. Direct Blue 160
Circulate 10 minutes
Raise temperature in 30 minutes to 200° F,
Run 15 minutes at 200° F. then add:
30.0% salt - (calcium and magnesium
free) in 4 portions over 15 minutes
Run at 200° F. for 45 minutes
Cool to 160° F.
Drop bath
Give cold rinse (original volume)
2.0% acetic acid (56%)
2.0% copper sulfate crystals
Circulate at 100° F. for 5 minutes
Raise temperature to 160° F.
Run at 160° F. for 20 minutes
Drop bath
Give two cold rinses (original
volume each)
Clip Tenter Frame
19
-------
DYEING PROCEDURE NO. 5
DYES:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE:
Rinse:
Soaping;
Rinse:
Dry:
Reactive
Exhaust
Rodney Hunt 20" Sample Dye Beck
Bleached, mercerized cotton
20:1
Set bath at room temperature with:
2.0 g/1 Ludigol (anti-reducing agent)
3.0% C.I. Reactive Red 120
Raise temperature to 120° F. and
hold for 10 minutes, then add:
100.0 g/1 salt (calcium and mag-
nesium free)
Add salt in 4 portions over 40
minutes while raising temperature
to 175° F.
Dye at 175° F. for 20 minutes, then add:
20 g/1 soda ash
1.2 g/1 caustic soda
Run at 175° F. for 50 minutes
Drop bath
Cold rinse (original volume)
Drop bath
Hot rinse at 150° F. (original volume)
Drop bath
Set bath at 100° F. with:
1 g/1 Barisol BRM (anionic surfactant)
1 g/1 soda ash
Run bath for 15 minutes at 212° F..
Cool to 160° F.
Drop bath
Give hot rinse at 150° F. (original
volume)
Give cold rinse (original volume)
Clip Tenter Frame
20
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DYES:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE:
Rinse:
Dry:
DYEING PROCEDURE NO. 6
Disperse
Exhaust
Rodney Hunt 20" Sample Dye Beck
Polyamide tufted carpet
20:1
Set bath at 100° F. with:
0.5% Avitone T (Anionic surfactant)
1.0% Merpol DA (nonionic surfactant)
0.5% Versene 100 (sequestrant)
Circulate 5 minutes and add dyes:
0.22% C.I. Disperse Yellow 3
0.075% C.I. Disperse Red 55
0.006% C.I. Disperse Violet 28
Add trisodium phosphate (pH 9.0-9.5)
Raise temperature to 190-200° F. over
45 minutes
Dye one hour
Cool bath to 160° F. and drop
Give one rinse at 110° F. (original
volume)
Clip Tenter Frame
21
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DYES:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE;
Rinse:
Dry:
DYEING PROCEDURE NO. 7
Acid
Exhaust
Rodney Hunt 20" Sample Dye Beck
Wool Fabric
30:1
Set bath at 100° F. and add:
2.0% Acetic acid (56%)
5.0% anhydrous sodium sulfate
5.0% C.I. Mordant Black 11
Circulate for 10 minutes at 120° F.
Raise temperature in 30 minutes to
212° F.
Run at 212° F. for 30 minutes, then add:
2.0% formic acid (pH 3.5-4)
Run for 30 minutes at 212° F.
Cool to 170° F.; add:
3.0% sodium bichromate
Raise temperature rapidly to 212° F.
Run at 212° F. for 30 minutes
Cool to 140° F.
Drop bath
Give two warm rinses (120° F.)
(original volume)
Drop bath
Clip Tenter Frame
22
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DYES:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE:
Rinse:
Dry:
DYEING PROCEDURE NO. 8
Basic
Exhaust
Rodney Hunt 20" Sample Dye Beck
Acrylic fabric
30:1
Set bath at 100° F. and add:
10.0% anhydrous sodium sulfate
2.0% acetic acid (56%) pH 4.5
2.0% Retarder HP (cationic retarder)
Circulate for 10 minutes at 120° F.
then add:
3.0% C.I. Basic Red 23
Circulate 10 minutes at 120° F.
Raise temperature in 45 minutes to
190° F.
Hold at 190° F. for 15 minutes
Raise temperature to 212° F. at 1° F.
per minute
Run at 212° F. for 60 minutes
Cool to 140° F. at 4° F. per minute
Drop bath
Give two warm rinses 110° F. (original
volume)
Drop bath
Clip Tenter Frame
23
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DYEING PROCEDURE NO. 9
DYE:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE:
Rinse:
Post Scour:
Disperse
Atmospheric Exhaust
Rodney Hunt 20" Sample Dye Beck
Tufted carpet
30:1
Set bath at 110° F. with
0.25% Irgaformal S 2 E (antifoam agent)
1.0% Calgon
1.0% monosodium phosphate
0.5% acetic acid (56%) pH 4.5-5.0
Circulate 10 minutes, then add over
a 10 minute period the following:
1.5% C.I. Disperse Yellow 42
1.5% C.I. Disperse Blue 87
0.5% Compound 8-S (surfactant)
Raise temperature to 160° F. at
3° F. per minute, then add over 15
minute period:
10.0% Carolid 3F (biphenyl carrier)
Run 10 minutes at 160° F.
Raise temperature to 212° F. at
3° F. per minute, then add over
15 minute period:
10.0% Carolid 3F (biphenyl carrier)
Run 10 minutes at 160° F.
Raise temperature to 212° F. at 3° F.
per minute
Run at 212° F. for 90 minutes
Cool to 160° F.
Drop bath
Give hot rinse 160° F. for 10 minutes
(original volume)
Drop bath
Set bath at 100° F. and add:
1.0% Merpol DA (nonionic surfactant)
1.0% trisodium phosphate
1.0% sodium hydrosulfite
Raise temperature to 160° F. and run
for 15 minutes
Drop bath
24
-------
Rinse: Give two warm rinses 120° F
(original volume)
Drop bath
Dry: Clip Tenter Frame
25
-------
DYE:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYE PROCEDURE:
Rinse:
After treatment;
Rinse:
Dry:
DYEING PROCEDURE NO. 10
Acid
Atmospheric Exhaust
Rodney Hunt 20" Sample Dye Beck
Polyamide filament, circular knit
30:1
Set bath at 100° F. with:
1.5% Alkanol ND (anionic surfactant)
20.% acetic acid (56%) pH 5-5.5
5.0% anhydrous sodium sulfate
Circulate for 10 minutes, then add
3.0% C.I. Acid Blue 40
Circulate 10 minutes
Raise temperature to 208° F. in
45 minutes
Run at 208° F. for 60 minutes
Cool to 140° F.
Drop bath
Give cold rinse (original volume)
Drop bath
Set bath at 100° F. with
2.0% acetic acid (56%) pH 4.4.5
5.0% Mesitol NBS (after-treating agent)
Circulate for 5 minutes
Raise temperature rapidly to 200° F.
Run at 200° F. for 20 minutes
Cool to 140° F.
Drop bath
Give one cold rinse (original volume)
Clip Tenter Frame
26
-------
DYEING PROCEDURE NO. 11
DYES:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE:
Rinse:
Dry:
Direct
Exhaust
Rodney Hunt 20" Sample Dye Beck
Rayon
30:1
Set bath at 100° F. with:
1.0 g/1 Levegal KN (leveling agent)
Circulate for 10 minutes and add
4.0% C.I. Direct Black 38
Raise temperature to 120° F. and
circulate for 10 minutes
Raise temperature to 200° F. over
30 minutes and add:
20.0% sodium sulfate
Add salt over a 30 minute period
Run at 200° F. for 60 minutes
Cool to 160° F.
Drop bath
Give two cold rinses (original volume)
Drop bath
Clip Tenter Frame
27
-------
DYEING PROCEDURE NO. 12
DYES:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE:
Rinse:
Diazotizing Bath:
Rinse:
Develop:
Rinse:
Direct-Develop
Exhaust
Rodney Hunt' 20" Sample Dye Beck
Rayon
30:1
Set bath at 100° F. with:
1.0 g/1 Levegal KN (leveling agent)
Circulate for 10 minutes and add
4.0% C.I. Direct Black 38
Raise temperature to 120° F. and
circulate for 10 minutes
Raise temperature to" 200° F. over
30 minutes and add:
20.0% sodium sulfate
Add over a 30 minute period
Run at 200° F. for 60 minutes
Cool to 160° F.
Drop bath
Give two cold rinses (original volume)
Set bath at 80° F. and add
3.0% sodium nitrite
Circulate for 5 minutes, then add:
7.5 hydrochloric acid 20° Be
Run 20 minutes at 80° F.
Drop bath
Give three cold rinses
Set bath at 80° F. and add:
1.5% Developer Z
Run for 20 minutes at 100° F.
Drop bath
Give three cold rinses
28
-------
Scour: Set bath at 100° F. and add:
0.5% Barisol BRM (surfactant)
Heat bath to 130° F. and run for
10 minutes
Drop bath
Rinse: Give two warm rinses at 120° F.
Drop bath
Dry: Clip Tenter Frame
29
-------
DYEING PROCEDURE NO. 13
DYE:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE:
Rinse:
Dry:
Basic, disperse and acid
Exhaust
Rodney Hunt 20" Sample Dye Beck
Carpet of nylon styling yarn
30:1
Set bath at 80° F. with:
0.25% Alkanol A-CN (surfactant)
0.25% trisodium phosphate
1.0% monosodium phosphate (pH 6.0-
6.2)
0.25% Sequestrene ST (sequestrant
agent)
Circulate bath for 10 minutes,
then add the below dyes over a
ten-minute period:
0.5% C.I. basic Red 73
0.1% C.I. Basic Blue 92
Run for 5 minutes, then add the
following dyes over a five-minute
period:
0.3% C.I. Disperse Yellow 3
0.1% C.I. Disperse Red 55
0.02% C.I. Disperse Blue 7
0.5% C.I. Acid Red 145
1.20% C.I. Acid Blue 122
0.10% C.I. Acid Yellow 198
Run 10 minutes
Raise temperature to 205° F,
2° F. per minute
Check pH and adjust to 6.0-6.2
Dye for 60 minutes at 205° F.
Cool bath to 140° F.
Drop bath
Give two cold rinses 70-80° F.
Drop bath
Clip Tenter Frame
at
30
-------
DYE:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO;
DYEING PROCEDURE:
Rinse
Scour:
Rinse:
Dry:
DYEING PROCEDURE NO. 14
Disperse
High temperature exhaust
35 Pound Gaston County Package dye
machine
Polyester yarn 15-1 Ib. packages
8:1
Set bath at 120° F. with 1.0 g/1
Compound
8-S (Anionic surfactant)
4.0% Tanalon Jet (carrier)
1.0% acetic acid (56%) pH = 5-6
Circulate 10 minutes, and add 4.0%
C.I. Disperse Blue 56
Dye was pasted up with equal amount
of the above surfactant
Raise temperature to 250° F. in
45 minutes
Dye at 250° F. for 60 minutes
Cool to 160° F.
Give one rinse at 100° F. for 5 minutes
Drop bath
Set bath at 100° F. and add
1.0 g/1 caustic soda
1.0 g/1 sodium hydrosulfite
1.0 g/1 Product BCO (surfactant)
Run at 160° F. for 10 minutes
Drop bath
Give one rinse at 160° F. for 5 minutes
Give one rinse at 120° F. for 5 minutes
Oven
31
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DYE:
PROCEDURE:
EQUIPMENT:
MATERIAL:
WET PICKUP:
DYEING PROCEDURE:
Padding:
Steaming:
Rinsing:
Oxidation:
Rinsing:
Soaping:
Rinsing:
Dry:
DYEING PROCEDURE NO. 15
Sulfur
Continuous (pad-chemical pad-steam-
wash-oxidize)
Continuous dye range
Bleached mercerized cotton
80%
Pad fabric at 110° F. with quick
immersion using:
180 g/1 C.I. Sulfur Black 1
22.5 g/1 Sodyefide B (sodium sulfide)
2.0 g/1 Penetrant SCA (surfactant)
60 sec. at 214° F.
1st wash box - cold
2nd wash box - cold
3rd wash box
7.5 g/1 hydrogen peroxide
7.5 g/1 acetic acid (56%) at 140° F.
4th wash box - 140° F.
5th wash box
2.0 g/1 Orvus K Paste (surfactant)
at 180° F.
6th wash box - 140° F.
Dry cans
NOTE: 100 yards of fabric was used on continuous dye range.
120 liters of solution used in each wash box.
32
-------
DYE:
PROCEDURE:
EQUIPMENT:
MATERIAL:
WET PICKUP:
DYEING PROCEDURE:
Padding:
Dry:
Fixation:
Rinse:
Soaping:
Rinse:
Dry:
DYEING PROCEDURE NO. 16
Reactive
Continuous (pad-dry-thermofix-
wash-dry)
Pad-Tenter Frame - Continuous Dye
Range
Bleached mercerized cotton
80%
40.0 g/1 C.I. Reactive Red 40
75.0 g/1 urea
3.0 g/1 Ludigol (anti-reducing agent)
20.0 g/1 soda ash
20.0 g/1 Superclear 100N (thickener)
Padding temperature 100° F.
225° F.
Thermofix at 330° F./90 seconds
1st wash box - cold
2nd wash box - cold
3rd wash box - 160° F.
4th wash box - 2.0 g/1 Barisol
BRM (anionic surfactant) at 200° F.
5th wash box - 180° F.
6th wash box - cold
Dry cans
NOTE: 100 yards of fabric was used in this dyeing.
120 liters of solution used in each wash box.
33
-------
DYES:
PROCEDURE:
EQUIPMENT:
MATERIAL:
WET PICKUP:
DYEING PROCEDURE:
Padding:
Dry:
Thermosol:
Chemical Pad:
Steam:
Rinse:
Oxidation:
Rinse:
Soaping:
Rinse:
Dry:
DYEING PROCEDURE NO. 17
Vat/Disperse
Thermosol - Pad - Steam
Pad-Tenter Frame - Continuous Dye
Range
50/50 Polyester/cotton
70%
Pad to 70% wet pick-up with:
32.0 g/1 C.I. Disperse Blue 62
16.0 g/1 C.I. Disperse Orange 41
6.4 g/1 C.I. Disperse Brown 2
22.0 g/1 C.I. Vat Green 8
16.5 g/1 C.I. Vat Black 25
15.0 g/1 C.I. Vat Green 3
15.0 g/1 Superclear 100N (thickener)
1.0 g/1 Alkanol WXN (surfactant)
Predry fabric at 250° F.
Thermosol at 410° F. for 9.0 seconds
60.0 g/1 caustic soda
60.0 g/1 sodium hydrosulfite at
80% wet pick up
Steam fabric 45 seconds at 214° F.
1st wash box - cold
2nd wash box - cold
3rd wash box
4.0 g/1 Hydrogen peroxide
4.0 g/1 acetic acid (56%)
30 seconds exposure at 140° F.
4th wash box - 140° F.
5th wash box
2.0 g/1 Orvus K Paste (surfactant)
at 200-210° F.
6th wash box - 140° F.
Dry cans
34
-------
DYES:
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE:
Rinse:
Dry:
DYEING PROCEDURE NO. 18
Basic
Atmospheric Exhaust
Rodney Hunt 20" Sample Dye Beck
Polyester "Dacron" T-92
30:1
Set bath at 120° F. with:
1.0% acetic acid (56%) pH 5
5.0% sodium sulfate
Circulate 10 minutes, then add
1.5% C.I. Basic Blue 41
1.5% C.I. Basic Yellow 11
Heat bath to 160° F. at 2° F. per
minute, then add:
5.0 g/1 Chemocarrier KD5W (carrier)
Circulate 10 minutes
Raise temperature in 25 minutes to
212° F.
Run at 212° F. for 60 minutes
Cool slowly to 160° F.
Drop bath
Give two rinses at 120° F.
5 minutes each rinse (original
volume)
Clip Tenter Frame
35
-------
DYES:
PROCEDURE:
EQUIPMENT:
MATERIAL:
WET PICKUP:
DYEING PROCEDURE:
Wet Out:
Pad Bath:
Steam:
Rinse:
Dry:
DYEING PROCEDURE NO. 19
Basic, disperse, acid
Kuster, Continuous
Kuster carpet dye range
Nylon Carpet T-844/T-845/T-847
Wet out 110%, padding 400%
Wet out carpet in:
2.0 g/1 Merpol ST (surfactant) at
130° F.
2.5 g/1 Syngum D-47-D (thickener)
1.0 g/1 Alkanol A-CN (surfactant)
1.0 g/1 Duponol F.A.S. (foaming
agent)
0.60 g/1 C.I. Basic Yellow 31
0.2 g/1 C.I. Acid Blue 298
0.02 g/1 Stylacy1 Red RB
0.20 g/1 C.I. Disperse Blue 7
Pad bath temperature at 80° F.
Running speed - 5 yards per minute
8 minutes at 212° F.
Rinse at 75° F.
Give three rinses at this temperature
in 40:1 bath rinses
36
-------
DYES :
PROCEDURE:
EQUIPMENT:
MATERIAL:
LIQUOR RATIO:
DYEING PROCEDURE:
Salt Rinse:
Coupling Bath:
Rinse:
DYEING PROCEDURE NO. 20
Naphthol
Exhaust
Gaston County 35 pound package dye
machine
Bleached cotton yarn 15-1 Ib.
packages
8:1
Prepare machine at 85° F. with:
5.0% caustic soda
Run at 110° for 10 minutes, add
2.0% Naphthol AS-SW solution
1/2 solution inside out
1/2 solution outside in
Run 30 minutes at 130° F., then add:
10.0% salt
Run 15 minutes
Drop bath - drain machine
Make up solution of:
8 oz/gal salt
Add to machine and run 10 minutes
at 60° F.
Drop bath - drain machine completely
Make up solution of:
8.0% Fast Scarlet R salt
1.0% acetic acid (56%)
Add solution to machine and run cold
in machine for 30 minutes
Drop bath
Raise temperature to 170° F. over
20 minutes
Drop bath
37
-------
Soaping: 2.0% Product BCO (surfactant)
2.0% soda ash
0.5% oz/gal Calgon
Raise temperature to 200° F.
Run 20 minutes
Cool to 180° F.
Drop bath
Rinse: Give three rinses at 75° F. each
rinse
5 minutes each rinse
Extract: Hydro Extractor
Dry: Oven
38
-------
SECTION V
CHARACTERIZATION OF DYEING WASTEWATERS
Dyeing Wastewaters were generated at North Carolina State
University at Raleigh. Small aliquots (1/2 gallon) of each
wastewater were preserved and sent to member companies of
ADMI for analysis of the selected trace metals including
cadmium, chromium, copper, lead, mercury, and zinc and for
analysis of benzidine and phenols in wastewaters. Samples
for trace metal analysis were preserved, handled and analyzed
according to EPA approved methods.1 Samples for benzidine
analysis were preserved by addition of 25 ml of cone. HC1
per liter of sample. Samples preserved for trace metal
analysis were also used for phenolics analysis.
Wastewaters were transported in stainless steel containers
to the UNC Wastewater Research Center in Chapel Hill. There
they were stored under refrigeration until use. Wastewaters
were mixed thoroughly with a mechanical stirrer before sampl-
ing. As soon as possible after arrival samples of waste-
water were removed for raw wastewater characterization by
the methods indicated in Table 3. An exception to this was
the BODa analysis which was delayed until an acclimated
seed was developed (10 days).
Results from analysis of dyeing wastewaters for trace metals,
benzidine, and phenols are given in Table 4. A summary of
the other raw wastewater characteristics is presented in
Table 5.
Generally, cadmium, chromium, and copper were found to be
present in amounts less than 0.1 mg/1. Notable exceptions
are dyeing wastewaters no, 2 and no. 7 for chromium, and no.
4 for copper. In dyeing system no. 2, chromium is present
in the dye as a part of the dye molecule. System no. 7 uses
a mordant dye that requires after-chroming with 3,0% sodium
dichromate. System no. 4 uses after-copperable direct dye
requiring 2.0% copper sulfate in the dye bath.
Lead and zinc were found to be present in amounts smaller
than 1.0 mg/1. Mercury was generally present in quantities
lower than the detection limit of 0.5 yg/1. Phenols were
observed, in most systems, in quantities of less than 0.5
mg/1. Phenols in higher quantities can all be explained by
the use of carriers, based on phenolics, in dyeing systems.
aAll BOD references are to 6005
39
-------
TABLE 3.
ANALYTICAL PROCEDURES
Parameter
Benzidine
BOD5, total
" , soluble
Chloride
Color
Nitrogen, NH.
" N03~
" N02~
PH
Phenolics
Phosphorus, total
Solids, suspended
" dissolved
TOC, total
soluble
Trace metals
Procedure
Adaption of chloramine-T
oxidation procedure
YSI DO Analyzer (Probe)
As above, after filtration
(1) Specific ion probe
(2) Mercuric nitrate titration
ADMI procedure
Automated phenolate
Automated hydrazine reduction
Automated diazotization
Automated digestion and then
automated phenolate
Electrometric
4-aminoantipyrine with dis-
tillation
Persulfate digestion followed
by atuomated SnCl2 method
Gooch crucible filtration,
103°C (Method 224 C)
Gravimetric, 103°C
Dow-Beckman Carbonaceous
Analyzer, Model 915 (Dual
Channel)
As above, after filtration
See Appendix
Reference
See Appendix
APHA, AWWA, .
WPCF, 1971'
Orion techni-
cal litera-
ture
APHA, AWWA,
WPCF, 19713
ADMI, 19732
FWPCA, 19694
4
FWPCA, 1969
FWPCA, 19694
FWPCA, 19694
APHA, AWWA,
WPCF, 19713
EPA, 19741
FWPCA, 1969
APHA, AWWA,
WPCF, 19713
APHA,,AWWA,
WPCF, 19713
FWPCA, 19694
FWPCA, 1969'
EPA, 19741
40
-------
TABLE 4. ANALYSIS OF DYEING SYSTEMS WASTES
Dyeing
Procedure
Number
1
2
3
'4
5;
6'
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Metal Content in mg/1
Cadmium
0.02
0.01
<0.01
0.21
0.09
0.01
0.01
<0.01
0.02
0.01
0.01
0.01
0.01
<0.01
<0.01
<0.01
0.01
<0.01
<0.01
0.05
Chromium
<0.01
1.59
<0.01
0.11
0.12
0.05
38.3
0.01
<0.01
<0.01
<0.01
<0.01
0.01
0.02
0.01
<0.01
0.21
<0.01
<0.01
0.01
Copper
0.05
0.01
0.01
17.0
0.10
0.05
0.11
0.05
0.04
0.08
0.04
0.41
0.10
0.12
0.72
0.07
0.88
0.05
0.05
0.07
Lead
<0.01
0.10
0.02
0.10
0.08
0.06
0.08
<0.01
0.20
0.08
<0.10
<0.10
0.20
<0.10
<0.05
<0.05
0.05
<0.05
0.05
0.05
Zinc
0.12
0.05
0.02
0.06
0.17
0.16
0.84
0.17
0.18
0.23
0.40
0.31
0.15
0.61
0.36
0.09
0.66
0.83
0.10
24.5
Mercury
yg/i
<0.5
<0.5
2.0
3.0
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
Phenol
mg/1
23.9
0.07
0.01
O.Q2
0.02
0.06
0.24
0.13
0.40
0.50
0.02
0.61
0.02
0.05
0.06
0.45
<0.01
0.02
Benzidine
yg/i
<10
16
<10
7.6
<10
4.2
7.6
<10
<10
<10
<2
<1
<1
41
-------
TABLE 5, RAW WASTEWATER CHARACTERISTICS
Dyeing No. 1 2
Substrate Cotton Polyamide
1:2 Metal
Dye Class Vat Complex
RAW WASTE CHARACTERISTICS
ADMI Color 1910 370
Apparent
ADMI Color3
TOC, mg/1 265 400
BOD, mg/1 294 570
pH 11.8 6.8
Cl~, mg/1 190 neg.
Susp.
solids, mg/1 41 5
Total Dissol.
Solids, mg/1 3945 1750
Total P,
mg/1
Kjeldahl N,
mg/1 ^20 ^200
NH3-N, mg/1
N02/N03-N,
mg/1 <1
-------
TABLE 5. RAW WASTEWATER CHARACTERISTICS (continued)
Dyeing No. 11 12
Substrate Rayon Rayon
Direct
Dye Class Direct Developed
RAW WASTE CHARACTERISTICS
ADMI Color 12,500 2730
Apparent ADMI
ADMI Color3
TOC, mg/1 140 55
BOD, mg/1 15 12
PH 6.6 3.2
Cl~, mg/1 61 130
Susp.
solids, mg/1 26 13
Total Dissol.
Solids, mg/1 2669 918
Total P, mg/1 1.3 0.6
Kjeldahl N, 11. o 6.0
mg/1
NH3-N, mg/1
N02/N03-N, 1.75 16.5
13
Polyamide
Carpet
Disperse,
Acid, Cationic
210
720
130
42
6.7
10
8
450
6.0
5.0
inter fer.
0.5
14
Polyester
Disperse
1245
360
198
10.2
1680
76
1700
0.7
13.5
inter fer.
0.3
15 16 17
Cotton Cotton Polyester/
Cotton
Sulfur Reactive Disperse/Vat
450 1390
.400 230
990 102
3.7 9.1
42 57
34 9
2000 691
16.5
9.0 197.5
interfer. 10.0
2.6 0.5
365
1100
350
360
10.1
167
27
2292
1.65
14.0
12.0
0.9
18 19 20
Polyester Polyamide Cotton
Carpet
Disperse,
Basic Acid. Cationic Nanhl-hnls
1300
2040
1120
1470
5.0
17
4
1360
2.3
12.5
3.5
<0.3
<50
190
160
130
6.5
22
49
258
24.0
5.5
<1.0
0.1
2415
170
200
9.3
7630
387
10,900
5.1
11.5
1.5
1.3
Apparent ADMI Color Values were obtained by omitting the Celite filtration step from the published ADMI procedure
-------
Benzidine analyses were ca^r/ied out for only thirteen of the
wastewaters and the values obtained were generally lower than
10 yg/1.
Color was measured according to the ADMI procedure. Diffi-
culties were encountered with color measurement of some dye-
ing wastewaters. For example, with some wastewaters the
color was significantly reduced during the Gelite filtration
step of the color measurement procedure. On the other hand,
turbidity in unfiltered samples interfered with color mea-
surement. To obtain realistic color measurements of turbid
dyeing wastewaters, dilutions were made. Dilution reduced
the turbidity and enabled a more accurate determination of
color in unfiltered samples. Throughout the study dilutions
were made and the values compared with those of undiluted
samples. Dilution proved a valid technique for- arriving at
apparent color values.
Wastewaters from dyeing of synthetic fibers with disperse
dyes generally had lower color values (Table 5). Of these,
wastewaters from carpet dyeing showed the least color.
Since in some cases (nos. 4, 8, 13, 17, 18, 19) much of the
color was removed in the filtration step, the color was also
measured on unfiltered samples, usually by dilution. Color
of dyeing wastewater no. 8 was measured after centrifugation.
Wastewaters generally exhibited low BOD (less than 400 mg/1)
with the exception of no. 15 (sulfur on cotton, continuous
procedure) and no. 18 (cationic on polyester by atmospheric
exhaust procedure). For comparison, the BOD of domestic
sewage is around 200-300 mg/1. Values for BOD could not be
obtained for no. 5 since some component of this dyeing
wastewater interfered with microbial activity.
With the exception of no. 18, TOC values were also low (less
than 400 mg/1); that of domestic sewage is around 200-300
mg/1.
Suspended solids levels were generally low with the excep-
tion of no, 9 (disperse on polyester carpet by atmospheric
exhaust procedure) and no. 20 (azoic on cotton by exhaust
procedure).
In all cases, total phosphorus was less than 25 mg/1; for
comparison, the total phosphorus in domestic sewage is in
the range of 10-12 mg/1.
Total Kjeldahl nitrogen (organic + ammonia nitrogen) was
likewise low (less than 20 mg/1) with the exception of no.
16 (reactive on cotton by continuous procedure, with urea
44
-------
addition) and no, 2 (1;2 metallized on polyamide by exhaust
method, ammonium acetate addition), Domestic sewage con-
centrations are in the range of 25-50 mg/1.
High levels of chloride and total dissolved solids were found
in no. 5 and no. 20.
Raw wastewater pH generally fell in the range of 4-8,5.
Highly alkaline pH values (greater than 9,0) were found in
wastewater nos. 1, 5, 14, 16, 17, and 20. With the excep-
tion of no. 14, these alkaline pH's were associated with
cotton dyeings. Highly acid pH values (less than 4) were
noted in nos. 12 and 15.
Overall, the wastewaters from the 20 dyeings showed much
variation, as expected. In all cases, they were character-
ized by color and by organic content associated with sub-
stantial oxygen demand. The major goals of this project
were directed toward removal of these two components.
References
1. EPA. Methods for Chemical Analysis of Water and Wastes.
U. S. Environmental Protection Agency, Office of
Technology Transfer, Washington, D,C. 1974.
2. Allen, W,, R. E. Derby, C. E. Garland, J. M. Peret,
W. B, Prescott, and M, Saltzman. Determination of
Color of Water and Waste Water by Means of ADMI
Color Values. In ADMI, Dyes and The Environment;
Reports of Selected Dyes and Their Effects, Vol. I.,
American Dye Manufacturers Institute, Inc., N.Y.
September 1973.
3. APHA, AWWA, WPCF. Standard Methods for the Examination
of Water and Wastewater, 13th ed., American Public
Health Association, N.Y. 1971.
4. FWPCA. FWPCA Methods for Chemical Analysis of Water and
Wastes. U, S, Dept. of Interior, Federal Water
Pollution Control Administration, Analytical Quality
Control Laboratory, Cincinnati, Ohio. 1969.
45
-------
SECTION VI
BIOLOGICAL TREATMENT
Biological treatability of 20 colored wastes from textile
carpet dyeing operations was investigated in laboratory-
scale studies. Many dyes resist biodegradation. Some, how-
ever, can be degraded biologically or can be removed from
wastewaters by sorption onto biological floe. On the other
hand, presence of some dyes, because of interference with
the metabolism of organisms involved in oxidation of carbon-
aceous and nitrogenous compounds, may interfere with treat-
ment of the non-colored waste components.1
Treatability of each wastewater was investigated in a series
of experiments employing two-liter Erlenmeyer flasks. In
each case, three sets of conditions were tested:
Set A - Dilutions of wastewater seeded with activated
sludge from a bench-scale plant treating com-
bined municipal and industrial wastewater from
the City of Durham (dyeing wastewaters nos. 1-
5) or municipal wastewater from the Town of
Chapel Hill (dyeing wastewaters nos. 6-20), i.e.,
organisms not acclimated to the specific dyeing
wastewater.
Set B - Dilutions seeded with microorganisms acclimated
to the wastewater being tested (activated sludge
from a pilot plant fed Durham or Chapel Hill waste-
water supplemented with the dyeing wastewater).
Set C - Dilutions unseeded, but with Hg(II) added to
prevent biological activity.
Sect C served as a control to distinguish between biological
and nonbiological changes.
In each case, BOD nutrients2 and yeast extract-^ were added
to assure that nutrients and vitamins were not limiting.
Initial pH was adjusted to pH 7.0. All sets were tested in
duplicate. In each set, three wastewater dilutions were
tested - 1, 10, and 100%, Each set was incubated on a shaker
(80-90) rpm) in the dark at 20°C for 21 days. Initially and
after incubation the samples were analyzed for soluble BOD,
soluble TOC, color,"and distribution of nitrogen species.
In addition, for the 10% dilution the course of biological
decomposition was monitored three times per week by
46
-------
removal of samples for TQC Analysis, Figure 2 shows the
experimental design.
Analyses were conducted according to the methods described
in Table 3. In each case, soluble TOC and BOD were deter-
mined by filtering the sample through a glass fiber filter
or a membrane filter (0,8 ]im pore size) prior to analysis.
Because solubilization of organics occurred in some cases,
it was possible for soluble TOC to increase during the study.
BOD determinations were not performed on samples from Set C
because of the presence of mercury. Color analyses were
conducted according to the ADMI procedure4. Nitrogen species
were determined on an unfiltered sample. A detailed de-
scription of the procedures used in the biodegradability
studies is given in the Appendix.
Results indicate that, in the majority of cases, biological
treatment did not reduce color of dyebath wastewaters to
levels which will be acceptable for discharge. On the other
hand, in the majority of cases, presence of color did not
interfere with BOD removal. In one case, however, the waste-
water proved severely inhibitory to microbial activity and
there was no removal of BOD; and in several cases, nitri-
fication was inhibited. Effect of biological treatment on
BOD, TOC, and color is shown in summary Tables 6, 7, and 8.
Effect of wastes on nitrification is shown in summary Table
9. The course of TOC removal at the 10% dilution is shown
graphically in Figures 3-22.
Results are presented for each dyeing wastewater in the fol-
lowing discussion.
Dyeing Wastewater No. 1. Vat Dyes on Cotton - Exhaust
Dyes: Vat Blue 18, Vat Black 13, Vat Orange 2; other com-
ponents: Caustic soda, sodium hydrosulfite, acetic acid,
surfactants, sodium perborate, tetrasodium pyrophosphate.
BOD removals of > 97% were achieved in all dilutions in both
acclimated and unacclimated cultures (Table 10). TOC removals
were dependent on the dilution, with 100% removal at 1% di-
lution, over 80% removal at the 10% dilution, and 60-70%
removal at 100%. Much greater removals were achieved in
seeded than in unseeded samples. Color removal was dependent
on dilution and type of culture. At the 10% dilution, 85%
of the color was removed by acclimated seed, 68% by the un-
acclimated seed. Color removal was less than 20% at the
100% strength. There was some inhibition of nitrification
47
-------
I
O
2
UJ
SEWAGE
SEWAGE + DYE ^WASTE
O
UJ
UJ
I
I UNACCLIMATED
SEED I
DYE
WASTE
pH ADJUSTED
UNSEEDED / TO 7
Hg-INHIBITED
1% SERIES
10% SERIES
100% SERIES
FIGURE 2. Experimental Design for Biological Study
48
-------
TABLE 6. EFFECT OF BIOLOGICAL TREATMENT ON BOD, TOC, AND
COLOR REMOVAL: 100% DILUTION
Dye Class
Vat
Disperse
Disperse
Disperse
Disperse
Vat & Disperse
Sulfur
Reactive
Reactive
Substrate
Cotton
Polyester
Polyamide Carpet
Polyester Carpet
Polyester
Polyester-
Cotton
Cotton
Cotton
Cotton
Dye# Set
1 A-100
B-100
C-100
3 A-100
B-100
C-100
6 A-100
B-100
c-ioo
9 A-100
B-100
C-100
14 A-100
B-100
C-100
17 A-100
B-100
C-100
15 A-100
B-100
C-100
5 A-100
B-100
C-100
16 A-100
B-100
C-100
TOC,
Initial
251
249
266
276
289
285
192
191
195
280
255
250
320
355
445
289
363
327
510
460
184
111
199
118
120
131
mg/1
Final
98
73
179
163
183
264
72
72
151
115
113
168
232
223
268
85
83
372
52
54
98
117
85
175
24
30
185
TOC
% Removal
61
71
33
41
37
7
62
62
22
59
56
33
28
37
40
70
77
+ 14
90
88
36
23
22
80
75
+ 41
BOD5/ mg/1
Inital
246
222
288
294
129
126
234
174
180
165
>128
>128
810
870
Final
4
1
<3
3
:!
<2
<2
4
22
32
38
-
BOD5
% Removal
98
100
99
99
>99
>99
>99
>99
98
87
>75
>70
100
100
toxic —
118
120
1
1
99
>99
Color, ADMI Units
Initial
1,886
1,080
1,458
348
255
311
86
86
85
333
326
334
1,141
647
1,072
371
367
364
1,435
1,240
1,345
4,084
4,123
719
730
727
Final
1,199
937
1,528
217
246
377
110
139
139
262
260
353
1,162
1,316
1,165
302
312
367
692
882
1,090
3,991
4,162
690
712
724
% Removal
17
13
+ 5
38
4
+ 21
+ 28
+ 62
+ 64
21
20
+ 6
+2
+ 9
18
15
0
52
29
19
2
+ 1
4
2
-------
TABLE 6. EFFECT OF BIOLOGICAL TREATMENT ON BOD, TOG, AND
COLOR REMOVAL: 100% DILUTION (continued)
Dye Class
Basic
Acid
Azoic
1:2 Metal
, Complex
Direct (After-
Copperable)
Direct
Substrate
Polyacrylic
Polyester
Polyamide
Cotton
Polyamide
Cotton
Rayon
Direct Rayon
Developed
Disperse + Acid Polyamide
+ Cationic Carpet
18
10
20
11
12
13
TOC, mq/1
Set
A-100
B-100
C-100
A-100
B-100
C-100
A-100
B-100
C-100
A-100
B-100
C-100
A-100
B-100
C-100
A-100
B-100
C-100
A-100
B-100
C-100
A-100
B-100
C-100
A-100
B-100
C-100
Initial
255
270
245
1150
1170
1020
280
330
305
174
176
173
492
452
472
143
139
134
170
180
200
66
70
68
115
119
121
Final
22
117
192
346
275
1040
211
190
305
58
55
158
123
123
522
27
27
145
153
154
185
45
43
~~
53
53
77
TOC
% Removal
91
57
22
70
76
+ 2
25
42
0
67
69
9
67
73
+ 10
81
81
+ 8
10
14
8
32
38
54
55
36
BOD5, mq/1
Initial
198
222
1530
1620
270
216
204
216
530
560
132
108
51
54
42
41
90
102
Final
153a
76
258
216
<3
<3
3
<1
5
4
5
6
<3
<3
~
<1
<1
___
11
14
BOD,
% Removi
23
66
83
87
— — —
>99
>99
99
100
99
99
96
94
>94
>94
>98
>98
88
86
s_
Color, ADMI Units
Initial Final % Removal
Ll,260a 12,790b
12,750b
15,930b
650
670
1,050
3,110
2,990
2,925
1,172
1,304
1,059
3,300
3,529
2,970
2,850
2,805
2,619
300
242
261
577
564
554
12,750
12,107
12,675
,190
,860
2,950
637
642
653
509
497
537
297
358
281
623
716
11,350
13,636
13,938
2,455
2,770
2,860
210
257
410
None
45
50
0
6
15
2
82
82
80
1
+48
+ 8
+ 8
+27
11
+ 13
+ 10
23
3
3
67
60
37
,unfiltered
centrifuged
-------
TABLE 6. EFFECT OF BIOLOGICAL TREATMENT ON BOD, TOCf AND
COLOR REMOVAL: 100% DILUTION (continued)
Ul
TOC, mg/1
Dye Class
Disperse + Acid
+ Cationic
Acid/Chrome
Substrate
Polyamide
Carpet
Wool
Dye# Set
19 A-100
B-100
C-100
7 A-100
B-100
c-ioo
Initial
150
146
155
210
245
200
Final
34
34
92
48
34
204
TOC
% Removal
77
77
41
77
86
+ 2
BOD^, mg/1
Initial Final
129 2
144 2
216 <1
216 <1
BOD5
% Removal
98
99
>99
>99
Color,
Initial
28
24
27
ADMI Units
Final % Removal
Too low to i
not measured,
10 % dilution
neasu
see
Key: A - Unacclimated seed; B - Acclimated seed; C - Unseeded, HgCl2 added
-------
TABLE 7. EFFECT OF BIOLOGICAL TREATMENT ON BOD, TOC, AND
COLOR REMOVAL: 10% DILUTION
Dye Class Substrate Ljyeff am: ±
Vat Cotton 1 A-10
R-l 0
Disperse Polyester
Disperse Polyamide Carpet
Disperse Polyester Carpet
Disperse Polyester
Sulfur Cotton
Reactive cotton
Reactive cotton
Basic Polyacrylic
Basic Polyester
Acid Polyamide
Azoic Cotton
1:2 Metal Complex Polyamide
Direct (After- Cotton
(copperable)
Direct Rayon
Direct Developed Rayon
Disperse + Acid Polyamide
+ Cationic Carpet
Disperse + Acid Polyamide
+ Cationic Carpet
Acid/Chrome Wool
C-10
3 A-10
B-10
C-10
6 A-10
B-10
C-10
9 A-10
B-10
C-10
14 A-10
B-10
C-10
17 A-10
B-10
C-10
15 A-10
B-10
C-10
5 A-10
B-10
C-10
16 A-10
B-10
C-10
8 A-10
B-10
C-10
18 A-10
B-10
C-1C
10 A-10
B-10
r-i n
20 A-10
B-10
C-10
2 A-10
B-10
C-10
4 A-10
B-10
C-10
11 A-10
B-10
C-10
12 A-10
B-10
C-10
13 A-10
B-10
C-10
19 A-10
B-10
C-10
7 A-10
B-10
C-10
TOC,
50
45
48
49
49
45
36
38
37
49
53
50
50
50
49
63
58
67
68
63
39
49
36
35
39
41
44
44
117
127
] 36
59
64
62
52
47
46
65
71
65
43
40
44
40
43
53
25
24
25
31
30
26
27
27
26
47
46
47
mg/1
9
7
18
16
16
65
7
9
37
9
9
50
25
29
42
14
14
59
5
3
67
18
18
4
4
55
10
14
40
8
12
142
26
29
6
8
44
16
13
74
6
6
30
11
14
41
2
3
22
4
22
0
22
6
6
42
TOC
82
84
62
67
67
+ 44
80
76
0
82
79
0
50
42
78
76
12
93
96
0
54
63
89
88
+ 41
73
68
9
93
90
+ 7
5S
55
3
83
83
4
77
82
+ 14
86
85
32
72
67
23
92
88
12
87
87
15
100
96
15
87
87
11
BOD5, mg/1
50 1
50 <1
--
76 1
72 1
—
47 <1
50 <1
50 <1
53 <1
__
34 <1
35 <1
>47 10
= 51 7
—
114 ^3
106 <3
TOXIC
---
36 <1
35 <1
—
55 3
60 6
174 <1
204 <1
—
69 <1
63 <1
—
59 ' 1
t4 <1
—
39 4
41 4
44 4
41 4
42 <1
46 <1
---
35 <1
32 <1
—
35 3
34 3
30 <1
52 <1
44 <1
BOD5 Color, ADMI Units
98
>98
99
99
—
>98
>98
= 98
= 98
>97
>97
>78
= 86
--
>97
= 97
--
—
—
=97
=97
—
94
90 (u
>99
= 99
--
>98
=98
—
= 98
>98
—
90
91
-"
91
90
= 98
= 98
—
= 97
>97
—
91
91
= 97
= 97
>98
>98
270
252
186
94
103
62
8
49
19
34
160
177
169
92
66
52
164
142
93
541
562
550
256
282
191
1720
nfilter
116
155
326
350
320
34')
297
349
187
91
22
403
420
403
1491
1508
1395
306
294
295
107
140
97
12
14
117
105
. 93
86
38
238
52
40
89
Too low for
analysis
68
85
+28
45
61
+44
Too low for
analysis
150
166
200
62
56
66
33
36
42
530
549
192
195
172
398 *
ed)599*
506
97
146
125
331
355
315
212
229
280
40
40
4 3
336
306
372
1003
1591
1585
182
209
163
36
40
39
Too low for
analysis
147
167
148
6
6
+ 18
33
15
+ 27
80
75
55
2
0
25
31
10
77
65
16
6
+ 2
+1
2
38
23
20
79
44
17
27
8
33
+ 6
+14
40
29
45
66
71
60
+ 26
+59
+ 59
*centrifuged
Key: A - Unacclimated seed; B - Acclimated seed; C - Unseeded, HgCl2 added
52
-------
TABLE 8. EFFECT OF BIOLOGICAL TREATMENT ON BOD, TOC, AND
COLOR REMOVAL: 1% DILUTION
Dye Class Substrate
Vat Cotton
TOC, mg/1 TOC BOD,-f mg/1 BODg Color, ADMI Units
Seta Initial Final % Removal Initial Final % Removal Initial Final % Removal
Disperse Polyester 3 A-l 22 0 luu ,, , 98 40 14 65
37 22 41
Disperse Polyamide- 6 A-l 24 4 SJ Jb « >"
Carpet B-1 '7 4 85 37 2 95
U1
Disperse Polyester- Q a-1 ^ n 10° 35 ™ ^ -- - -^- -- -- -- ^^-^ 72 40
73 54 26
L21 72 40
79 57 28
-------
TABLE 8. EFFECT OF BIOLOGICAL TREATMENT ON BOD, TOC, AND
COLOR REMOVAL: 1% DILUTION (continued)
TOC, mg/1 TOC BOD^ mg/1 BODs Color, ADMI Units
Dye Class Substrate Dye « Set Initial Final % Removal Initial Final % Removal Initial Final % Removal
Direct Rayon 12 A-l 23 0 100 27 <1 96 84 26 70
Developed B-l 23 0 100 34 <1 97 71 26 63
C-l 20 22 +10 -- — — 80 44 45
Disperse + Polyamide 13 A-l 24 2 92 22 <1 >95 22 22 0
Acid + Basic Carpet B-l 19 2 89 23 <1 96 45 26 42
C-l 19 22 +15 — -- — 16 20 +25
Disperse + Polyamide 19 A-l 19 0 100 25 1 96
Acid + Basic Carpet B-l 19 0 100 19 <1 95
C-l 20 12 40
Acid/Chrome Wool 7 A-l 30 2 93 24 <1 96
B-l 29 0 100 23 <1 96
C-l 28 24 14
aln this table and in those following the number indicates the amount of wastewater in the test medium, i.e., A-l refers
to a 1% strength; A-10, to 10%, and A-100 to full-strength wastewater. A refers to test with unacclimated seed; B, to
tests with acclimated seed; and C, to tests with unseeded medium with HgCl2 addition.
-------
TABLE 8, EFFECT OF BIOLOGICAL TREATMENT ON BOD, TOC, AND
COLOR REMOVAL; 1% DILUTION (continued)
on
Dye Class
Reactive
Basic
Basic
Acid
Azoic
1:2 Metal
Complex
Direct (After
Copperable)
Direct
Substrate
Cotton
Polyacrylic
Polyester
Polyamide
Cotton
Polyamide
Cotton
Rayon
16
18
10
20
11
TOC. ma/1
Set
A-l
B-l
C-l
A-l
B-l
c-i
A-l
B-l
C-i
A-l
B-l
C-l
A-l
B-l
C-l
A-l
B-l
C-l
A-l
B-l
C-l
A-l
B-l
C-l
Initial
20
25
23
27
26
28
34
32
34
32
34
32
47
43
36
23
23
23
24
31
29
32
30
39
Final
0
1
24
1
9
22
2
5
34
0
2
29
0
2
30
0
0
24
0
1
20
2
1
26
TOC
% Removal
100
96
+ 4
96
65
21
94
84
0
100
94
9
100
95
17
100
100
4
100
97
31
94
97
33
BOD^ , mg/1
Initial
20
25
38
26
~~
42
47
50
41
61
34
—
20
20
—
29
41
—
44
48
—
Final
<1
<1
2
2
~"
4
<1
__
<1
1
~~~
<1
<1
3
4
—
2
0
—
2
<1
—
BOD,;
% Removal
>95
>96
"~
95
92
98
98
~~
>98
98
~~
>98
>97
85
80
—
93
100
—
95
98
—
Color
Initial
—
™" ~~
—
~~
--
—
_ _
--
~~
64
48
26
52
52
57
239
303
221
, ADMI Units
: q 7 = ~
Final r
—
—
—
—
—
22
20
8
14
30
32
36
71
78
s Removal
—
—
—
—
—
—
73
42
47
85
77
65
-------
TABLE 9, EFFECT OF DYEING WASTEWATERS ON NITRIFICATION
10% Strength
100% Strength
Dye #
Set
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
TKN,
Initial
4.25
3.6
24.0
24.5
25.5
7.0
7.5
4.5
4.5
4.0
6.5
5.0
7.3
5.0
6.0
5.0
5.5
5.5
5.5
4.0
4.5
5.0
mg/1
Final
6.0
7.75
7.5
15.0
15.2
26.5
7.75
8.25
7.25
5.5
5.75
3.0
<3.0
6.8
3.2
2.7
2.2
4.5
2.5
7.8
4.8
5.5
5.2
3.5
N02-N +
Initial
>0.3
<0.3
0.6
0.7
<0.5
>0.3
<0.3
<0.3
<0.3
<0.3
<0.3
<0.3
<0.3
<0.3
<0.3
<0.3
<0.3
0.3
0.2
0.2
<0.3
<0.3
<0.3
N03-N, mg/1
Final
2.1
0.6
<0.5
12.2
12.4
<0.3
1.3
<0.3
<0.3
<0.3
<0.3
<0.3
6.0
0.8
<0.3
6.4
6.2
<0.5
7.2
1.0
<0.3
<0.5
<0.5
<0.5
TKN,
mg/1
Initial Final
23.0
30.0
203
206
231
12.0
13.5
14.0
9.5
10.0
10.0
14.2
14.5
13.2
18.0
19.0
18.0
18.0
19.5
17.5
17.5
15.5
14.5
26.0
20.5
19.5
20.5
23.7
11.0
12.0
10.5
16.2
16.0
13.0
6.0
6.0
17.5
13.5
15.0
10.2
11.0
8.0
15.7
N02~N +
Initial
0.5
<0.3
0.7
1.3
1.4
1.1
1.2
0.9
0.9
0.6
0.6
0.5
1.0
0.9
0.9
0.5
0.4
0.4
0.7
0.6
0.6
0.3
<0.3
<0.3
N03-N, mg/1
Final
0.5
<0.3
0.9
— . — —
1.1
<0.3
<0.3
<0.3
<0.3
<0.3
0.6
0.7
0.6
0.6
10.6
10.8
0.8
1.1
0.8
0.8
0. 9
0. 8
1.6
-------
TABLE 9. EFFECT OF DYEING WASTEWATERS ON NITRIFICATION
(continued)
10% Strength 100% Strength
TKN, me
Dye #
10
11
12
13
14
15
16
17
18
TKN, mg/1
Set
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
Initial
6.0
7.5
7.0
5.0
5.0
4.5
4.5
7.5
7.0
5.5
3.0
3.5
3.0
4.5
3.0
3.0
5.5
5.0
5.0
19.5
21.5
20.5
6.0
7.5
5.0
5.0
5.0
5.5
Final
2.2
2.2
3.0
7.5
9.5
4.5
6.0
5.0
5.8
2.5
2.2
2.2
3.0
3.2
4.0
2.2
3.0
4.5
4.2
8.5
8.5
21.5
2.0
2.0
3.7
<2.0
2.0
4.0
N02-N .+ NO,-N, mg/1 TKN, mg/1 N02~N + N03-
Initial
0.3
0.3
<0.3
<0.4
0.4
<0.4
0.5
0.5
0.2
<0.5
<0.5
<0.5
<0.3
<0. 3
<0.3
<0.4
<0.4
<0.4
0. 95
1. 1
<0. 6
<0.3
<0.3
<0.2
<0.4
<0.4
<0.4
Final
6.0
6.2
<0.4
0.3
<0.7
<0.3
6.9
5.8
<0.7
6.8
4.9
5.0
<0.3
1.0
<0.5
<0.4
7.9
7.4
<0.4
15.0
15.5
1.4
6.7
6.9
<0.1
3.0
3.5
<0. 1
Initial
13.5
13.5
12.5
12.5
11.5
15.5
17.0
15.0
5.5
7.5
7.0
13.5
13.5
13.5
12.0
12.5
12.5
127.5
122.5
122.5
20.0
22.0
17.0
17.5
16.0
15.5
Final
6.8
6.2
5.2
15.0
13.8
12.5
15.0
14.5
17.3
7.0
8.5
6.8
23.8
28.0
23.5
20.2
22.5
14.0
41.5
40.0
120.5
15.2
19.2
19.0
15.5
16.0
17.0
Initial
0.8
0.7
0.8
1.1
0.95
0.7
2.0
2.0
2.7
<0.95
<0.95
<0.95
0.4
0.6
<0.5
<0.4
<0.4
<0.4
3.6
4.0
3.5
1.11
1.19
1.01
<0.4
<0.4
<0.4
-N, mg/1
Final
2.4
3.1
<0.3
<0.4
<0.4
<0.4
8.5
8.2
2.8
<0.4
2.0
0.75
0.5
<0.5
<0.6
<0.2
1.3
2.3
60.5
63.5
3.7
0.35
0.27
1.02
<0 . 1
<0 . 1
0.2
-------
Ul
O3
TABLE 9. EFFECT OF DYEING WASTEWATERS ON NITRIFICATION
(continued)
10% Strength
TKN, mg/1
Dye #
19
20
Set
A
B
C
A
B
Initial
2.5
2.
2.5
7.0
7.5
6.0
Final
2.0
2.0
2.0
— _ _ .
N02-N + N03-N, mg/1 TKN, mg/1
Initial
0.3
0.1
<0.1
1.6
1.7
1.5
Final
3.2
3.6
<0.3
Initial
10.0
9.5
7.5
24.5
31.5
25.0
Final
5.0
7.5
6.8
— _ «
=jjy uii
N02-N + N03-N, mg/1
Initial
0.2
0.2
<0.1
13.0
13.0
13.0
Final
0 3
1 i
<0.3
-------
TABLE 10 .
TOC
, BIOLOGICAL TREATABILITY
BOD5
mg/1
Set a
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
Initial
23
27
26
50
45
48
251
249
266
Final
0
0
28
9
7
18
98
73
179
% Removal
100
100
+8
82
84
62
61
71
33
OF WASTEWATER NO. 1
Color, ADMI
Units
mg/1
Initial
35
37
--
50
50
— —
246
222
Final
1
1
—
1
<1
— —
4
1
—
% Removal
97
97
—
98
>98
— _._
98
100
Initial
_ « «
270
252
186
1,886
1,080
1,458
Final
_ _ _
86
38
238
1,199
937
1,528
% Removal
__. —
68
85
+28
17
13
+5
01
TABLE 11. EFFECT OF WASTEWATER NO. 1 ON NITRIFICATION
Set
A
B
C
10% Strength
TKN,
Initial
4.25
3.6
mg/1
Final
6.0
7.75
7.5
N02-N + N03-
Initial
>0.3
<0.3
-N, mg/1
Final
2.1
0.6
<0.5
100% Strength
TKN,
Initial
23.0
30.0
mg/1
Final
26.0
20.5
N02-N +
Initial
0.5
<0.3
0.7
N03-N, mg/1
Final
0.5
<0.3
0.9
aln this table and in those following the number indicates the amount of wastewater
in the test medium,i.e., A-l refers to a 1% strength; A-10, to 10%; and A-100 to
full-strength wastewater.
-------
in the 10% dilution and tptal inhibition at the 100% strength
(Table 11) .
Since some removal of TOC was obtained in the Hg-inhibited
samples and since over the course of the experiment (Figure
3) TOC decreased in the 10% strength flask with mercury,
evidently non-biological phenomena are responsible for part
of the TOC removal.
Dyeing Wastewater No. 2. 1;2 Metal Complex Dye on Polyamide
- Exhaust
Dyes: Acid Black 52; other components: Capracyl leveling
salt (an ethylene oxide concentrate), ammonium acetate,
sodium sulfate.
BOD removals of greater than 90% were achieved by both ac-
climated and unacclimated seed and at both 10% and 100%
strengths (Table 12). Total removal of TOC was achieved in
seeded flasks at 1%. At higher strengths, TOC removals were
slightly better with acclimated seed and at the 10% dilution.
Some color removal was achieved at the 10% dilution (79% by
unacclimated, 44% by acclimated) but not at the 100% dilu-
tion. At the 10% level the wastewater did not affect nitri-
fication (Table 13); nitrogen data were not available for the
100% strength.
As shown in Figure 4, over the course of the experiment the
pattern of TOC removal was similar in the seeded flasks,
whereas little or no reduction was achieved in the Hg-inhib-
ited flasks, where in fact there was a slight increase in
soluble TOC.
Dyeing Wastewater No. 3. Disperse Dyes on Polyester - Ex-
haust
Dyes: Disperse Blue 87, Disperse Yellow 42; other components:
ethylene oxide condensate surfactant, complex diary1 sul-
fonate, ortho-phenylphenol carrier, acetic acid, soda ash,
sodium hydrosulfite, anionic surfactant.
As shown in Table 14, BOD removals of £98% were achieved by
both acclimated and unacclimated seed at all wastewater
strengths. TOC removals occurred only in seeded flasks and
were related to wastewater strength: ^ 92% at 1% strength,
67% at 10% strength, ~40% at 100% strength. Additional con-
firmation of the association of TOC removal with seed is
shown in Figure 5 which indicates TOC values over 21 days
in the 10% dilutions. In fact, solubilization of TOC occur-
60
-------
8 10 12 14
TIME, days
16 18 20
FIGURE 3. Dyeing Wastewater No. 1 (Vat Dyes on Cotton):
Biodegradation. Unacclimated seed, o; acclimated
seed, •; unseeded, a.
8 10 12 14
TIME, days
16 18 20
FIGURE 4.
Dyeing Wastewater No. 2 (1:2 Metal Complex Dye on
Polyamide)* Biodegradation. Unacclimated seed,
o; acclimated seed, •; unseeded, o.
61
-------
TABLE 12. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 2
TOC
BOD,
Color, ADMI Units
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
(Ti
K)
mg/1
Initial
23
23
23
65
71
65
492
452
472
Final
0
0
24
16
13
74
123
123
522
% Removal
100
100
4
77
82
+14
67
73
+10
mg/1
Initial
20
20
—
39
41
530
560
Final
3
4
—
4
4
—
5
4
—
% Removal
85
80
—
90
91
—
99
99
—
Initial
64
48
26
187
91
22
300
242
261
Final
22
20
8
40
40
43
297
358
281
% Removal
66
58
69
79
44
1
+48
+ 8
Set
A
B
C
TABLE 13. EFFECT OF WASTEWATER NO. 2 ON NITRIFICATION
10% Strength
N02~N + N03-N, mg/1
TKN, mg/1
InitialFinal Initial
24.0
24.0
25.5
15.0
15.2
26.5
0.6
0.7
<0.5
Final
12.2
12.4
<0.3
100% Strength
TKN,
Initial
203
206
231
mg/1
Final
N02-N +
Initial
1.3
1.4
1.1
N03-N, mg/1
Final
1.1
-------
U)
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
Set
A
B
C
mg/1
Initial
22
26
26
49
49
45
276
289
285
TABLE 14.
TOC
Final %
0
2
31
16
16
65
163
183
264
TABLE 15.
BIOLOGICAL TREATABILITY OF WASTEWATER NO. 3
BOD,- Color,
Removal
100
92
+19
67
67
+44
41
37
7
EFFECT
10% Strength
TKN
Initial
7.0
7.5
, mg/1
Final
7.75
8.25
7.25
N02~N +
Initial
>0.3
<0.3
<0.3
mg/1
ADMI Units
Initial Final % Removal Initial Final
44 1
44 1
76 1
72 1
288 <3
294 3
OF WASTEWATER
NO--N, mg/1
Final
1.3
<0.3
<0.3
98
98
99
99
99
99
40
55
37
94
103
62
348
255
311
14
12
22
52
40
89
217
246
377
% Removal
65
78
41
45
61
+44
38
4
+21
NO. 3 ON NITRIFICATION
100% Strength
TKN, mg/1
Initial Final
12.0 19.5
13.5 20.5
14.0 23.7
N02-N
+ NO
Initial
1.2
0.9
0.9
3-N, mg/1
Final
<0.3
<0.3
<0.3
-------
70
60
50
\
j!f 40
•k
o
P 30
20 -
10 -
0 2 4 6 8 10 12 14 16 18 20
TIME, days
FIGURE 5. Dyeing Wastewater No, 3 (Disperse Dyes on Poly-
ester) : Biodegradation. Unacclimated seed, o;
acclimated seed, •; unseeded, o.
0
FIGURE 6.
8 10 12 14 16
TIME, days
18 20
Dyeing Wastewater No. 4 (After-Copperable Direct
Dye on Cotton): Biodegradation. Unacclimated
seed, o; acclimated seed, •; unseeded, a.
64
-------
red in the unseeded flasks. Color removal was best with.
acclimated .seed, at 1% and at 10% strength, This dyeing
wastewater was inhibitory to nitrification at both 10 and
100% strengths (Table 15),
Dyeing Wastewater No, 4, After-Copperable Direct Dye on
Cotton '- Exhaust
Dye: Direct Blue 160; other components: sodium metaphos-
phate, phosphated long-chain alcohols, soda ash, anionic
surfactant, sequestrant, NaCl, acetic acid, copper sul'fate.
Ninety percent or greater removals of BOD were achieved at
1%, 10%, and 100% strengths by both acclimated and unaccli-
mated seed. TOG removals were unusually good: 81% at 100%,
85-86% at 10%. Only a small portion (<30%)of the TOG removal
was due to nonbiological processes (Table 16). Further con-
firmation of this observation is shown in Figure 6. Color
removals were extremely poor (<27%) and in some cases solu-
bilization occurred, resulting in an increase in color as
measured by the ADMI color test. This dyeing wastewater
totally inhibited nitrification at both 10 and 100% strengths
(Table 17).
Dyeing Wastewater No. 5. Reactive Dye on Cotton - Exhaust
Dye: Reactive Red 120; other components: anti-reducing
agent, NaCl, soda ash, caustic soda, anionic surfactant.
Dyeing Wastewater No. 5 was the most inhibitory of the waste-
waters studied. It inhibited oxidation of carbonaceous
materials at 1%, 10%, and 100% strengths, even with "accli-
mated" seed. Nitrification was almost totally inhibited at
the 10% and 100% strengths with the exception of the non-
acclimated seed at 10% strength. At the 1% dilution TOC
removals were good in seeded flasks (74%, 91%). At greater
strengths TOC removals were poor: 54-63%in seeded flasks at
10% dyeing wastewater strength, 23-36% at 100% strength
(Table 18). Figure 7 indicates that after 2-4 days there
was little further removal of TOC. Color removal was nil
at 10% and 100% dyeing wastewater strength and 540% at the
1% wastewater strength.
Nitrification occurred at 10% strength with unacclimated
seed; no nitrification occurred at 10% strength in B or C
flasks, or in any of those at 100% strength (Table 19).
65
-------
CTi
TABLE 16. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 4
TOC
BOD,
Color, ADMI Units
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
mg/1
Initial
24
31
29
43
40
44
143
139
134
Final
0
1
20
6
6
30
27
27
145
% Removal
100
97
31
86
85
32
81
81
+8
mg/1
Initial
29
41
—
44
41
132
108
Final
2
0
—
4
4
—
5
6
—
% Removal
93
100
91
90
96
94
Initial
52
52
57
403
420
403
577
564
554
Final
14
30
32
336
306
372
623
716
% Removal
73
42
47
17
27
8
+3
+27
—
TABLE 17. EFFECT OF WASTEWATER NO. 4 ON NITRIFICATION
10% Strength
Set
A
B
C
TKN,
Initial
4.5
4.5
4.0
mg/1
Final
5.5
5.75
3.0
N02-N +
Initial
<0.3
<0.3
<0.3
N03-N, mg/1
Final
<0.3
<0.3
<0.3
100% Strength
TKN, mg/1
Initial Final
9.5 11.0
10.0 12.0
10.0 10.5
N02-N +
Initial
0.6
0.6
0.5
N03-N, mg/1
Final
<0.3
<0.3
0.6
-------
01
TABLE 18
TOC
. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 5
BOD5 Color, ADMI
mg/1
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
Initial
25
31
26
39
49
—
184
111
199
Final
2
8
26
18
18
117
85
175
% Removal
91
74
0
54
63
36
23
22
mg/1
Initial Final % Removal Initial
73
121
?g
— 541
inhibitory 562
— 550
4,084
inhibitory
4,123
Final
54
72
57
530
549
3,991
4,162
Units
% Removal
26
40
28
2
0
2
+1
TABLE 19. EFFECT OF WASTEWATER NO. 5 ON NITRIFICATION
10% Strength
100% Strength
Set
A
B
C
TKN,
Initial
6.5
5.0
7.3
mg/1
Final
3.0
6.8
3.2
N02-N +
Initial
0.3
0.3
0.3
N03-N, mg/1
Final
6.0
0.8
0.3
TKN,
Initial
14.2
14.5
13.2
mg/1
Final
16.2
16.0
13.0
N02-N +
Initial
1.0
0.9
0.9
N03-N, mg/1
Final
0.7
0.6
0.6
-------
8 10 12 14 16 18 20
TIME,days
FIGURE 7. Dyeing Wastewater No. 5 (Reactive Dye on Cotton):
Biodegradation. Unacclimated seed, o; acclimated
seed, •; unseeded, n.
I I I I
III!
10 12 14 16 18 20
TIME, days
0
FIGURE 8.
Dyeing Wastewater No. 6 (Disperse Dyes on Poly-
amide Carpet): Biodegradation. Unacclimated
seed, o; acclimated seed, •; unseeded, a.
68
-------
Dyeing Wastewater No. 6. Disperse Pyes on Polyamide Carpet -
Exhaust
Dyes: Disperse Yellow 3, Disperse .Red 55, Disperse Violet
28; other components; anionic and nonionic surfactants,
sequestrant, trisodium phosphate,
BOD removals of >95% were achieved with both acclimated and
unacclimated seed at all strengths. TOC removals occurred
in seeded flasks and were dependent on dilution: 83-85% at
1%, 76-80% at 10% strength, 62% at 100% strength. Associa-
tion of TOC removal with biological activity is confirmed
by TOC data over the 21-day period (Figure 8). Color levels
were extremely low, even in the full strength waste. At
full-strength there was no removal; on the contrary, soluble
color increased (Table 20). There was no inhibition of ni-
trification even at full strength (Table 21).
Dyeing Wastewater No. 7. Acid Chrome Dye on Wool - Exhaust
Dye: Mordant Black 11; other components: acetic acid,
anhydrous sodium sulfate, formic acid, sodium bichromate.
The BOD of Dyeing Wastewater No. 7 was easily removed, with
>96% removal at all strengths and with both acclimated or
unacclimated seed. TOC removals were associated with seeded
flasks and related to wastewater concentration: 93-100% re-
moval at 1% strength; 87% removal at the 10% strength, 77%
removal by unacclimated seed at 100%, and 86% removal by
acclimated seed at 100%. Association of TOC removal with
biological activity is confirmed by Figure 9. In contrast,
color removals were poor. Color tests performed on the
samples at 10% strength indicated that soluble color actually
increased during the incubation (Table 22). At 10% strength
this waste had no effect on nitrification by unacclimated
seed. A lesser degree of nitrification was obtained with
acclimated seed at 10%. At full-strength little or no in-
crease in oxidized nitrogen forms (nitrite + nitrate) was
obtained (Table 23).
Dyeing Wastewater No. 8. Basic Dye on Polyacrylic - Exhaust
Dye: Basic Red 23; other components: organic cationic pro-
duct as a retarder, sodium sulfate, acetic acid.
Dyeing Wastewater No. 8 was difficult to test due to its
tendency to sorb onto solid surfaces. For example, it ad-
hered to the Celite in the ADMI color test, BOD removals
of 90-94% were achieved at the 1% and 10% strengths, but at
69
-------
TABLE 20. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 6
TOC BODr Color, ADMI Units
mg/1
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-l 00
B-100
C-100
Initial
24
27
25
36
38
37
192
191
195
Final
4
4
24
7
9
37
72
72
151
% Removal
83
85
4
80
76
0
62
62
22
mg/1
Initial Final
36 4
37 2
47 <1
50 <1
129 <1
126 <1
% Removal
>97
95
>98
>98
>99
>99
Initial
—
8
86
86
85
Final %
--
Removal
--
Too low for
analysis
110
139
139
+28
+62
+64
Set
A
B
C
TABLE 21. EFFECT OF WASTEWATER NO. 6 ON NITRIFICATION
10% Strength
TKN, mg/1 N02~N + N03~N, mg/1
100% Strength
TKN, mg/1
N02-N + N03-N, mg/1
Initial
5.0
6.0
5.0
Final
2.7
2.2
4.5
Initial
<0.3
<0.3
<0.3
Final
6.4
6.2
<0.5
Initial
18.0
19.0
18.0
Final
6.0
6.0
17.5
Initial
0.5
0.4
0.4
Final
10.6
10.8
0.8
-------
0
8 10 12 14
TIME,days
16 18 20
FIGURE 9. Dyeing Wastewater No. 7 (Acid-Chrome Dye on Wool):
Biodegradation. Unacclimated seed, o; acclimated
seed, •; unseeded, n.
0
8 10 12 14 16 18 20
TIME.days
FIGURE 10. Dyeing Wastewater No. 8 (Basic Dye on Polyarylic):
Biodegradation. Unacclimated seed, o; acclimated,
•; unseeded, D.
71
-------
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
mg/1
Initial
30
29
28
47
46
47
210
245
200
TABLE 22
TOC
Final
2
0
24
6
6
42
48
34
204
BIOLOGICAL TREATABILITY OF WASTEWATER NO. 7
BOD5 Color, ADMI Units
% Removal
93
100
14
87
87
11
77
86
+2
mg/1
Initial Final
24 <1
23 <1
— —
52 <1
44 <1
— —
216 <1
216 <1
—
% Removal
96
96
—
>98
>98
—
>99
>99
—
Initial
w _ _
117
105
93
— —
Final
_ w ..
147
167
148
Not
10%
— —
% Removal
—
—
~ ~~
+ 26
+59
+59
measured,
dilution
— —
see
TABLE 23. EFFECT OF WASTEWATER NO. 7 ON NITRIFICATION
10% Strength
Set
A
B
C
TKN,
Initial
5.5
5.5
5.5
mg/1
Final
2.5
7.8
4.8
N02-N +
Initial
0.3
0.2
0.2
N03-N, mg/1
Final
7.2
1.0
<0.3
100% Strength
TKN,
Initial
18.0
19.5
17.5
mg/1
Final
13.5
15.0
10.2
N02-N +
Initial
0.7
0.6
0.6
NO--N, mg/1
Final
1.1
0.8
0.8
-------
the 100% strength only 23% was removed by unacclimated seed
and 66% by acclimated seed. TOC removals were erratic --
around 70% at the 10% strength, 57% by acclimated seed at
the 100% strength, and 91% removal by unacclimated seed at
100% strength, TOC removals were associated with presence
of seed (Table 24 and Figure 10), Because of the tendency
of the dye to sorb on Celite, color tests were performed on
unfiltered or on uncentrifuged samples. This waste had an
extremely high color - around 12,000 ADMI units at the 100%
strength. Some color was removed at the 10% strength,
evidently by non-biological processes, but residual colors
were 400-600 units. No color was removed at the 100%
strength. The waste interfered with nitrification at both
the 10% and 100% strengths (Table 25).
Dyeing Wastewater No. 9. Disperse Dyes on Polyester Carpet
- Exhaust
Dyes: Disperse Yellow 42, Disperse Blue 87; other compon-
ents: dispersing agent, biphenyl carrier, antifoam agent,
surfactants, sodium hydrosulfite, mono- and tri-sodium
phosphate, acetic acid.
BOD removals of 97-99% were achieved at 1%, 10%, and at 100%
strengths with both acclimated and unacclimated seed. TOC
removal was dependent on concentration: 100% removal at 1%
strength, around 80% at the 10% strength, around 60% at 100%
strength. TOC removal was associated with presence of seed
(Table 26 and Figure 11). Only 20% of the color was re-
moved at the 100% strength; at 10% strength, the remaining
color was too weak to measure accurately. At 10% strength,
the waste did not affect nitrification, and only partial
inhibition was noted at the 100% strength (Table 27).
Dyeing Wastewater No. 10. Acid Dye on Polyamide - Exhaust
Dye: Acid Blue 40; other components: anionic surfactant,
Mesitol NBS (Verona), sodium sulfate, acetic acid.
BOD removals of >98% were achieved at all strengths. TOC
removals varied with strength; they were associated with
biological activity (Table 28 and Figure 12). At the 10%
strength, ~55% of the TOC was removed by both unacclimated
and acclimated seed. At 100% strength, 42% of the TOC was
removed by acclimated seed; 25% by unacclimated seed. Ini-
tial color of the waste was high, ^3000 ADMI units. No
significant removals were obtained at either 10% or 100%
strengths. This waste, totally inhibited nitrification at
both the 10% and 100% strengths (Table 29).
73
-------
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
TABLE 24. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 8
TOC BODc Color, ADMI Units
mg/1
Initial
27
26
28
41
44
44
255
270
245
Final
1
9
22
10
14
40
22
117
192
% Removal
96
65
21
73
68
9
91
57
22
mg/1
Initial
38
26
55
60
198
222
Final
2
2
3
6
153a
76
% Removal
95
92
94
90
23
66
1720
11,260
398"
599b
506b
12,790
12,750
15,930
77
65
70
None
TABLE 25. EFFECT OF WASTEWATER NO. 8 ON NITRIFICATION
A
B
C
10% Strength
TKN,
Initial
4.0
4.5
5.0
mg/1
Final
5.5
5.2
3.5
N02~N +
Initial
<0.3
<0.3
<0.3
N03-N, mg/1
Final
<0.5
<0.5
<0.5
unfiltered
centrifuged
100% Strength
TKN,
Initial
17.5
15.5
14.5
mg/1
Final
11.0
8.0
15.7
N02~N +
Initial
0.3
<0.3
<0.3
N03-N, mg/1
Final
0.9
0.8
1.6
-------
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
Initial
31
31
29
49
53
50
280
255
250
TABLE 26
TOC
mg/1
Final
0
0
26
9
9
50
115
113
168
BIOLOGICAL TREATABILITY OF WASTEWATER NO. 9
BOD5 Color, ADMI Units
% Removal
100
100
10
82
79
0
59
56
33
mg/1
Initial Final
35 <1
— —
^ _ — —
50 <1
53 <1
— —
234 <2
174 <2
% Removal
97
—
~~
>98
>98
—
>99
>99
--
Initial
— __
49
19
34
333
326
334
Final % Removal
— — — —
Too low for
analysis
___
262 21
260 20
352 +6
Ul
TABLE 27. EFFECT OF WASTEWATER NO. 9 ON NITRIFICATION
10% Strength
-N + N03-N, mg/1
TKN, mg/1 NO
Set Initial Final Initial Final
A 6.0 2.2 0.3 6.0
B 7.5 2.2 0.3 6.2
C 7.0 3.0 <0.3 <0.4
100% Strength
TKN, mg/1
13.5
13.5
12.5
6.8
6.2
5.2
N02-N
Initial Final Initial
0.8
0.7
0.8
}-N, mg/1
Final
2.4
3.1
<0.3
-------
0 2
FIGURE 11.
4
8 10 12 14
TIME, days
16 18 20
Dyeing Wastewater No. 9 (Disperse Dyes
on Polyester Carpet): Biodegradation.
Unacclimated seed, o; acclimated seed,
•; unseeded, o.
2 4 6 8 10 12 14 16 18 20
TIME, days
FIGURE 12. Dyeing Wastewater No. 10 (Acid Dye on
Polyamide): Biodegradation. Unaccli-
mated seed, o; acclimated seed, •;
unseeded, D.
16
-------
TABLE 28. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 10
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
TOG
Initial
32
34
32
59
64
62
280
330
305
mg/1
Final
0
2
29
26
29
60
211
190
305
% Removal
100
94
9
56
55
3
25
42
0
BOD 5
Initial
50
41
69
63
270
216
mg/1
Final
<1
1
<1
<1
<3
<3
% Removal
>98
98
>98
>98
>99
>99
Color, ADMI Units
Removal Initial Final % Removal
326 331
350 355
320 315
3,300 3,110
3,529 2,990
2,970 2,925
+2
+1
2
6
15
2
TABLE 29. EFFECT OF WASTEWATER NO. 10 ON NITRIFICATION
10% Strength
Set
A
B
C
TKN,
Initial
5.0
5.0
4.5
mg/1
Final
7.5
9.5
4.5
N02-N +
Initial
<0.4
0.4
<0.4
N03~N, mg/1
Final
0.3
<0.7
<0.3
100% Strength
TKN,
Initial
12.5
11.5
mg/1
Final
15.0
13.8
12.5
N02-N +
Initial
1.1
0.95
0.7
N03-N, mg/1
Final
<0.4
<0.4
<0.4
-------
Dyeing Wastewater No. 11. Direct Dye on Rayon - Exhaust
Dye; Direct Black 38; other components; leveling agent,
sodium sulfate,
BOD removals of ;>94% were achieved in all strengths by both
acclimated and unacclimated seed, TOG removals were associ-
ated with biological activity (Table 30 and Figure 13) and
were a function of waste strength: 94-97% at 1% strength,
70% removal at 10% strength, only 10-14% removal at 100%
strength. Except at the 1% strength color removal was gen-
erally poor (<30%) , the best being achieved by the unaccli-
mated seed. In some flasks soluble color increased. Nitri-
fication occurred in both 10% and 100% wastewater strengths
(Table 31).
Dyeing Wastewater No, 12. Direct Developed Dye on Rayon
Dyes and other components; as for Dyeing Wastewater NO. 11,
with addition of the developer, 3-methyl-l-phenyl-5-pyrazo-
lone, hydrochloric acid, sodium nitrite, and surfactant.
BOD removals of >96% were obtained at all dilutions. TOC
removals were associated with biological activity (Table 32
and Figure 14) and were a function of wastewater strength:
100% removal at 1% strength, 88-92% removal at 10% strength,
and 32-38% removal at 100% strength. The amount of TOC re-
moved at all dilutions was about 20 mg/1 and this may indi-
cate that most of that removed was that contributed by the
yeast extract. Color removal was a function of initial
color level, with the best removals (63-70%) being obtained
in the 1% strength. Substantial removal of color (45%) was
achieved in unseeded flasks at the 1% and 10% strengths,
suggesting that nonbiological processes were involved. In-
sufficient data were available on nitrogen forms, so effect
on nitrification is unknown (Table 33).
Dyeing Wastewater No. 13. Disperse, Acid, and Basic Dyes on
Polyamide Carpet
Dyes: Basic Red 73, Basic Blue 92, Disperse Yellow 3, Dis-
perse Red 55, Disperse Blue 7, Acid Red 145, Acid Blue 122,
Acid Yellow 198; other components: surfactants, mono- and
tri-sodium phosphate, sequestrant.
BOD removals of >95% were achieved by both seeds at 1% waste
strength; at 10% strength, 91%; at 100% strength, 86-88%.
TOC removal was associated with presence of seed (Table 34
and Figure 15). Again, TOC removal was a function of dilu-
tion. TOC removals of 89-92% were achieved at 1% waste-
water strength; at 10% strength, 87%; at 100% wastewater
78
-------
TABLE 30. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 11
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
TOC
Initial
32
30
39
40
43
53
170
180
200
mg/1
Final
2
1
26
11
14
41
153
154
185
% Removal
94
97
33
72
67
23
10
14
8
BOD 5
Color, ADMI Units
mg/1
Initial Final
44
48
42
46
51
54
<3
<3
95
98
>98
>98
>94
>94
Initial
239
303
221
1491
1508
1395
12,750
12,107
12,675
Final
36
71
78
1003
1591
1585
11,350
13,636
13,938
% Removal
85
77
65
33
+6
+14
11
+13
+10
TABLE 31. EFFECT OF WASTEWATER NO. 11 ON NITRIFICATION
10% Strength
100% Strength
Set
A
B
C
TKN, mg/1
Initial Final
4.5 6.0
7.5 5.0
7.0 5.8
N02-N +
Initial
0.5
0.5
0.2
N03~N, mg/1
Final
6.9
5.8
<0.7
TKN,
Initial
15.5
17.0
15.0
mg/1
Final
15.0
14.5
17.3
N02-N +
Initial
2.0
2.0
2.7
N03-N, mg/1
Final
8.5
8.2
2.8
-------
50
2 4 6 8 10 12 14 16 18 20
TIME,days
FIGURE 13. Dyeing Wastewater No. 11 (Direct Dye on Rayon):
Biodegradation. Unacclimated seed, o; acclimated
seed, •; unseeded, n.
40 -
2 4 6 8 10 12 14 16 18 20
TIME, days
FIGURE 14. Dyeing Wastewater No. 12 (Direct Developed Dye
on Rayon): Biodegradation, Unacclimated seed,
o; acclimated seed, •; unseeded, n.
80
-------
TABLE 32. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 12
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
CO
TOC
BOD[
Initial
23
23
20
25
24
25
66
70
68
mg/1
Final
0
0
22
2
3
22
45
43
—
% Removal
100
100
+10
92
88
12
32
38
—
Initial
27
34
35
32
42
41
mg/1
Final
1
1
1
1
1
1
% Removal
96
97
97
97
98
98
Color, ADMI Units
Initial
84
71
80
306
294
295
3,190
2,860
Final
26
26
44
182
209
163
2,455
2,770
% Removal
70
63
45
40
29
45
23
3
•*
TABLE 33. EFFECT OF WASTEWATER NO. 12 ON NITRIFICATION
10% Strength
Set
A
B
C
TKN, mg/1
Initial Final
5.5 2.8
6.0 3.0
5.0 3.5
N02-N +
Initial
2.1
2.0
1.8
N03~N, mg/1
Final
6.8
6.7
2.0
100% Strength
TKN,
Initial
9.0
10.0
9.0
mg/1
Final
6.5
6.5
8.5
N02-N +
Initial
15.5
15.0
15.0
N03~N, mg/1
Final
22.5
22.0
17.5
-------
TABLE 34. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 13
CO
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
Initial
24
19
19
31
30
26
115
119
121
TOC
mg/1
Final
2
2
22
4
4
22
53
53
77
% Removal
92
89
+15
87
87
15
54
55
36
BOD
mg/1
5
Initial Final
22
23
—
35
34
—
90
102
—
95
96
--
91
91
—
88
86
—
Color
Initial
22
45
16
107
140
97
637
642
653
, ADMI
Final
22
26
20
36
40
39
210
257
410
Units
% Removal
0
42
+25
66
71
60
67
60
37
TABLE 35. EFFECT OF WASTEWATER NO. 13 ON NITRIFICATION
10% Strength
Set
A
B
C
TKN, mg/1
Initial Final
3.0 2.2
3.5 2.2
3.0 3.0
N02-N + N
Initial
<0.5
<0.5
<0.5
0.,-N, mg/1
Final
4.9
5.0
<0.3
100% Strength
TKN, mg/1
Initial Final
5.5 7.0
7.5 8.5
7.0 6.8
N02-N +
Initial
<0.95
<0.95
<0.95
N03-N, mg/1
Final
<0.4
2.0
0.75
-------
10 12 14 16 18 20
FIGURE 15. Dyeing Wastewater No. 13 (Disperse, Acid, and
Cationic Dyes on Polyamide Carpet): Biodegrada-
tion. Unacclimated seed, o; acclimated seed, •;
unseeded, D.
0
6 8 10 12 14 16 18 20
TIME, days
FIGURE 16. Dyeing Wastewater No. 14 (Disperse Dye on Poly-
ester) : Biodegradation. Unacclimated seed, o;
acclimated seed, •; unseeded, n.
83
-------
strength, 54-55%, Despite the mix of dyes, the wastewater
did not affect nitrification at 10% strength, and only
partial inhibition was noted at full-strength in the accli-
mated cultures. However, nitrification did not occur at
full-strength in the non-acclimated culture (Table 35).
Dyeing Wastewater No. 14. Disperse Dyes on Polyester
Dye: Disperse Blue 56; other components: trichlorbenzene
carrier, acetic acid, sodium hydrosulfite, cetyl betaine,
anionic surfactant, caustic soda,
BOD removals of 94% were achieved at 1% strength, and of
greater than 97% at 10% strength with both seeds; at 100%
wastewater strength, 98% BOD removal was achieved by unaccli-
mated seed, 87% by acclimated seed. TOC removal was associ-
ated with presence of seed (Table 36 and Figure 16). At 10%
strength, 42-50% removals were achieved. At 100% strength,
unacclimated seed showed 28% removal; acclimated seed, 37%
removal. At the 100% strength, the mercury-inhibited con-
trol experienced a 40% TOC removal, indicating that non-
biological processes were probably responsible for that re-
moval. No color removal was achieved at either strength.
Except with non-acclimated seed at 10% strength, Dyeing
Wastewater No. 14 totally inhibited nitrification at both
10% and 100% strengths (Table 37).
Dyeing Wastewater No. 15. Sulfur Dye on Cotton, Continuous
Process
Dye: Sulfur Black 1; other components: sodium sulfide and
sodium polysulfide, alkylarylsulfonates blend surfactant,
hydrogen peroxide, acetic acid.
Dyeing Wastewater No. 15 was readily treatable in comparison
with other wastewaters (Table 38 and Figure 17). BOD re-
movals of 97-100% were attained at both 10 and 100% waste-
water strengths by both seeds. TOC removals of 93-96% were
achieved at 10% wastewater strength; 88-90% at 100% waste-
water strength. Color removals, partially due to nonbio-
logical processes, were 75-80% at 10% wastewater strength;
29-52% at 100% strength. Unfortunately at the 100% strength
the initial wastewater color was so intense ( = 1300-1400
ADMI units) that even with the high percentage removals
there were residual color levels of 700-900. While at the
10% wastewater strength nitrification was not affected, at
100% strength nitrification did not occur (Table 39).
84
-------
00
Ul
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
TABLE 36. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 14
TOC BOD5 Color, ADMI Units
Initial
16
18
17
50
50
49
320
355
445
mg/1
Final
2
8
13
25
29
42
232
223
268
% Removal
88
56
24
50
42
9
28
37
40
mg/1
Initial
17
18
34
35
180
165
Final
1
1
<1
<1
4
22
% Removal
94
94
>97
>97
98
87
87
160 150
177 166
169 200
1,141 1,162
647 1,316
1,072 1,165
6
6
+18
+2
+9
TABLE 37. EFFECT OF WASTEWATER NO. 14 ON NITRIFICATION
10% Strength
100% Strength
Set
A
B
C
TKN, mg/1
Initial Final
4.5 3.2
3.0 4.0
3.0 2.2
N02-N +
Initial
<0.3
<0.3
<0.3
N03-N, mg/1
Final
1.0
<0.5
<0.4
TKN, mg/1
Initial Final
13.5 23.8
13.5 28.0
13.5 23.5
N02-N +
Initial
0.4
0.6
<0.5
N03-N, mg/1
Final
0.5
<0.5
<0.6
-------
CO
CTi
TABLE 38. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 15
TOC
BOD,
Color, ADMI Units
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
Initial
32
32
32
68
68
— —
510
460
*"" ^ ^
mg/1
Final
4
2
32
5
3
67
52
54
98
% Removal
88
94
0
93
96
0
90
88
—"— •
mg/1
Initial
23
25
—
114
106
810
870
— _
Final
3
3
—
<3
<3
—
<1
<1
—
% Removal
87
88
>97
>97
—
100
100
Initial
_.....
164
142
93
1,435
1,240
1,345
Final
33
36
42
692
882
1,090
% Removal
80
75
55
52
29
19
TABLE 39. EFFECT OF WASTEWATER NO. 15 ON NITRIFICATION
10% Strength
Set
A
B
C
TKN, mg/1
Initial Final
5.0 3.0
5.0 4.5
5.0 4.2
N02-N +
Initial
<0.4
<0.4
<0.4
N03~N, mg/1
Final
7.9
7.4
<0.4
TKN, mg/1
Initial Final
12.0 20.2
12.5 22.5
12.5 14.0
NO--N +
Initial
<0.4
<0.4
<0.4
NO--N, mg/1
Final
<0.2
1.3
2.3
-------
> 2 4 6 8 10 12 14 16 18 20
TIME,days
FIGURE 17. Dyeing Wastewater No. 15 (Sulfur Dye on Cotton):
Biodegradation. Unacclimated seed, o; acclimated
seed, •; unseeded, n.
10 12 14 16 18 20
0
FIGURE 18. Dyeing Wastewater No. 16 (Reactive Dye on Cotton)
Biodegradation. Unacclimated seed, o; acclimated
seed, •; unseeded, a .
87
-------
Dyeing Wastew.ater No. 16. Reactive Dyes on Cotton <- Continu-
QUS
Dye: Reactive Red 40; other components: urea, sodium m-
nitrobenzene-sulfonate, soda ash, natural gum thickener,
anionic surfactant,
BOD removals of 95% or greater were achieved by both accli-
mated and unacclimated seeds at 1%, 10%, and 100% dyeing
wastewater strengths. In seeded flasks, TOG removals of 88-^
89% were achieved at 10% wastewater strength, 75-80% at 100%
strength. Removal occurred only in seeded flasks (Table 40
and Figure 18). In contrast, in the mercury-inhibited
flasks TOC increased probably by solubilization. In all
cases, color removals were poor. At 10% wastewater strength
color decreased by 25-31% in seeded flasks; at 100% waste-
water strength, essentially no color removal occurred. Dye-
ing Wastewater No, 16 had no effect on nitrification, even
at 100% strength. The initial Kjeldahl nitrogen values
were unusually high (^ 125 mg N/l), probably due to the urea.
During the test period much of the Kjeldahl N was converted
to N02~-N and NO^-N (Table 41).
Dyeing Wastewater No. 17. Vat and Disperse Dyes on 50/50
Cotton-Polyester Blend, Continuous Dyeing, Thermosol-Pad-
Steam Process
Dyes: Vat Black 25, Vat Green 8, Vat Green 3, Disperse Blue
62, Disperse Orange 41, Disperse Brown 2; other components:
natural gums solution, sodium alkylaryl sulfonate, hydrogen
peroxide, acetic acid, caustic soda, sodium hydrosulfite.
BOD removals with Dyeing Wastewater No. 17 were difficult to
estimate since the initial strengths were underestimated.
However, since the raw waste had a BOD of 360 mg/1 it is esti-
mated that BOD removals at the 100% wastewater strength
were about 90%. TOC removals of 70-80% were achieved in
seeded flasks, whereas little or no TOC was removed in the
mercury-inhibited flasks (Table 42 and Figure 19). Color
removals were poor in all cases. While nitrification was not
affected at the 10% wastewater strength, it was strongly in-
hibited at the 100% strength (Table 43).
Dyeing Wastewater No. 18. Basic Dyes on Polyester, Atmo-
spheric Exhaust Process - Batch
Dyes; Basic Blue 41, Basic Yellow 11; other components:
carrier, acetic acid, sodium sulfate.
88
-------
TABLE 40. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 16
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
00
Set
A
B
C
TOG BOD5
mg/1 mg/1
Initial Final % Removal Initial Final % Removal Inn
Color, ADMI Units
.tial Final % Removal
20 0 100 20 <1 >95
25 1 96 25 <1 >96
23 24 +4 — — —
36 4 89 36 <1 >97 256 192 25
35 4 88 35 <1 >97 282 195 31
39 55 +41 — -- — 191 172 10
118 24 80 118 1 99 719 690 4
120 30 75 120 1 >99 730 712 2
131 185 +41 — — — 727 724 <1
TABLE 41. EFFECT OF WASTEWATER NO. 16 ON NITRIFICATION
10% Strength 100% Strength
TKN, mg/1 N02~N + N03-N, mg/1 TKN, mg/1
Initial Final Initial Final Initial Final
19.5 8.5 0.95 15.0 127.5 41.5
21.5 8.5 1.1 15.5 122.5 40.0
20.5 21.5 <0.6 1.4 122.5 120.5
N02-N + N03-N, mg/1
Initial Final
3.6 60.5
4.0 63.5
3.5 3.7
-------
TABLE 42. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 17
TOC
BOD,
Color, ADMI Units
mg/1
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
Initial
30
27
29
63
58
67
289
363
327
Final
6
6
32
14
14
59
85
83
372
% Removal
80
78
+10
78
76
12
70
77
+14
mg/1
Initial
47
40
>47
>128
>128
Final
9
10
10
7
32
38
••"•—
% Removal
81
75
>78
>86
>75
>70
Initial
92
66
52
371
367
364
Final
62
56
66
302
312
367
% Removal
— ,_
33
15
+27
18
15
0
TABLE 43. EFFECT OF WASTEWATER NO. 17 ON NITRIFICATION
10% Strength
100% Strength
Set
A
B
C
TKN,
Initial
6.0
7.5
5.0
mg/1
Final
2.0
2.0
3.7
N02-N +
Initial
<0.3
<0.3
<0.2
N03-N, mg/1
Final
6.7
6.9
<0.1
TKN, mg/1
Initial Final
20.0 15.2
22.0 19.2
17.0 19.0
N02-N +
Initial
1.11
1.19
1.01
N03-N, mg/1
Final
0.35
0.27
1.02
-------
8 10 12
TIME,days
14 16 18 20
FIGURE 19.
Dyeing Wastewater No. 17 (Disperse and Vat Dyes
on Polyester/Cotton): Biodegradation. Unaccli-
mated seed, o; acclimated seed, •; unseeded, n.
91
-------
BOD removals in Dyeing Wasteweiter No, 18 were dependent on
wastewater strength, At the 1% and 10% strengths, S.98% of
the BOD was removed, whereas at 100% strength only 83-87%
removals were achieved, TOC removals, likewise, were de-
pendent on wastewater strength. In seeded flasks, 90-93%
removals were obtained at 10%; at 100% strength, 70-76%.
TOC removals were achieved only in seeded flasks (Table 44
and Figure 20), In mercury-inhibited flasks, no TOC was re-
moved. In seeded flasks color removals were very poor at
10% dye strength, but 45-50% at full strength; the reason
for this is unknown. No color removal occurred in unseeded
flasks. Nitrification occurred at 10% strength but not at
100% strength (Table 45).
Dyeing Wastewater No. 19. Disperse, Acid, and Basic Dyes on
Polyamide Carpet, Kuster Simulation Process - Continuous'
Dyes: Basic Yellow 31, Acid Blue 298, Acid Red (Stylacyl
Red RB), Disperse Blue 7; other components: ethylene oxide
condensates, acetic acid or monosodium phosphate (for pH
adjustment), anionic surfactant, natural gum thickener.
BOD removals of >95% were achieved in all seeded dilutions.
TOC removals were unusually good (>77%) and were associated
with biological activity (Table 46 and Figure 21). At the
10% dilution, seeded flasks achieved 96-100% TOC removals,
whereas in the unseeded flasks only 15% was removed. At 100%
strength, the unacclimated seed removed 77% of the TOC; the
acclimated seed, 86%. In contrast, little or no TOC was re-
moved in the mercury-inhibited controls. The color levels
of Dyeing Wastewater No. 19 were so low that accurate esti-
mates of color could not be obtained. Nitrification was
not unaffected at the 10% strength, but was markedly inhib-
ited in the presence of the full-strength wastewater (Table
^*' / •
Dyeing Wastewater No. 20. Naphthol on Cotton - Exhaust Pro-
cedure'" ~~ ' ~~ ~~
Dyes: Azoic Coupling Compound 7, Azoic Diazo Component 13;
other components: acetic acid, caustic soda, soda ash,
Calgon, common salt.
In seeded flasks BOD removals of £98% were achieved. TOC
removals were also good and were associated only with seeded
flasks (Table 48 and Figure 22). At the 10% dyeing waste-
water strength, seeded flasks removed 83-88% of the TOC; at
100% wastewater strength, 67-69% TOC removals were experi-
enced. Color removals were much better at 100% strength
92
-------
TABLE 44. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 18
TOC
BODC
Color, ADMI Units
U)
mg/1
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
Set
A
B
C
Initial Final
34
32
34
117
127
136
1150
1170
1020
TKN,
Initial
5.0
5.0
5.5
2
5
34
8
12
142
346
275
1040
TABLE
10%
mg/1
Final
<2.0
2.0
4.0
% Removal
94
84
0
93
90
+7
70
76
+2
45. EFFECT
Strength
N02-N + NO
Initial
<0.4
<0.4
<0.4
mg/1
Initial
42
47
174
204
1530
1620
Final % Removal
4 98
<1 98
<1 >99
<1 >99
258 83
216 87
Initial Final
116 97
155 146
125
1,172 650
1,304 670
1,059 1,050
% Removal
16
6
45
50
0
OF WASTEWATER NO. 18 ON NITRIFICATION
3-N, mg/1
Final
3.0
3.5
100%
TKN, mg/1
Strength
N02-N + N03~N,
Initial Final Initial
17.5 15.
16.0 16.
15.5 17.
5 <0.4
0 <0.4
0 <0.4
mg/1
Final
<0 . 1
0.2
-------
140 -
8 10 12 14
TIME.days
20
FIGURE 20. Dyeing Wastewater No. 18 (Basic Dyes on Polyester,
Atmospheric Exhaust Process): Biodegradation.
Unacclimated seed, o; acclimated seed, •; unseeded,
94
-------
TABLE 46. BIOLOGICAL TREATABILITY OF WASTEWATER NO. 19
TOG
BOD,
Color, ADMI Units
U1
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
Set
A
B
C
mg/1
Initial
19
19
20
27
27
26
150
146
155
TKN
Initial
2.5
2.5
2.5
Final
0
0
12
0
1
22
34
34
92
TABLE
, mg/1
Final
2.0
2.0
2.0
% Removal
100
100
40
100
96
15
77
77
41
47. EFFECT
10% Strength
N02-N + NO
Initial
0.3
0.1
mg/1
Initial
25
19
30
29
129
144
Final % Removal In
1 96
<1 95
<1 >97
<1 >97
2 98
2 99
litial Final % Removal
5
12
14
28
24
27
Too low for
analysis
Too low for
analysis
OF WASTEWATER NO. 19 ON NITRIFICATION
3-N, mg/1
Final
3.2
3.6
<0.3
100%
TKN, mg/1
Initial Final
10.0 5.0
9.5 7.5
7.5 6.8
Strength
N02-N
+ N03-N, mg/1
Initial Final
0.2
0.2
0.3
1.1
<0.3
-------
8 10 12 14 16 18 20
TIME, days
FIGURE 21. Dyeing Wastewater No. 19 (Disperse, Acid, and
Basic Dyes on Polyamide Carpet, Kuster Process):
Biodegradation. Unacclimated seed, o; acclimated
seed, •; unseeded, Q.
8 10 12 14
TIME .days
16 18 20
FIGURE 22, Dyeing Wastewater No. 20 (Naphthol on Cotton,
Exhaust Procedure): Biodegradation. Unacclimated
seed, o; acclimated seed, •; unseeded, o.
96
-------
TABLE 48. BIOLOGICAL TREATABILITY OF WASTEWATER NO, 20
vo
-j
Set
A-l
B-l
C-l
A-10
B-10
C-10
A-100
B-100
C-100
Set
A
B
C
TOC
mg/1
Initial Final !
47
43
36
52
47
46
174
176
173
TKN,
Initial
7.0
7.5
6.0
0
2
30
6
8
44
58
55
158
TABLE 49
10%
mg/1
Final
5.0
5.8
7.3
BOD 5
mg/1
Color, ADMI Units
1 Removal Initial Final % Removal Initial Final
100
95
17
88
83
4
67
69
9
. EFFECT OF
Strength
N02~N + NO.,
Initial
1.6
1.7
1.5
61 <1
34 <1
59 <1
44 <1
204 3
216 <1
WASTEWATER
-N, mg/1
Final
8.0
6.9
1.5
>98 - —
>97
>98 340 212
>98 297 229
349 280
99 2,850 509
100 2,805 497
2,619 537
NO, 20 ON NITRIFICATION
100% Strength
TKN, mg/1 N02~N +
Initial Final Initial
24.5 21.8 13.0
31.5 27-5 13.0
25.0 25-° 13.0
% Removal
38
23
20
82
82
80
N03-N, mg/1
Final
13.5
12.8
12.8
-------
than at 10% and occurred in both seeded and unseeded flasks.
It is thought that the lower solubility of the color at full-
strength may be responsible for the unusual results obtained,
The red color was easily removed on standing or by filtra-
tion, yielding a clear straw-colored solution. Insufficient
data were available to determine the effect of this waste-
water on nitrification (Table 49).
CONCLUSIONS
Overall, the following conclusions were reached:
(1) in most cases biological treatment of dyeing
wastewaters, while inadequate for color
removal, can achieve high (>90%) levels of
soluble BOD removal
(2) in one case, the dyeing wastewater was in-
hibitory to removal of BOD, even at low
strengths, possibly indicating the need for
segregating this wastewater from biological
treatment systems
(3) biological treatment alone appears to be
inadequate for color removal
(4) in at least 10 cases, the dyeing wastewaters
are inhibitory to nitrification, or at least
have organic nitrogen components not suscep-
tible to nitrification, a factor which must
be considered if effluent standards require
low levels of Kjeldahl nitrogen
(5) there was little or no consistency among
dyeing classes in relation to effect on BOD,
TOC, color, or ammonia removal.
98
-------
REFERENCES
1. Little, L. W. , W. B, Durkin, J. C. Lamb III, and M. A.
Chillingworth. Effect of Biological Treatment on
Toxicity of Dyes to Fish. In ADMI, Dyes and The
Environment; Reports on Selected Dyes and Their
Effects, Vol. II, American Dye Manufacturers Insti-
tute, Inc,, New York, September 1974.
2. APHA, AWWA, WPCF. Standard Methods for the Examination
of Water and Wastewater, 13th ed., American Public
Health Association, New York, 1971.
3. Bunch, R. L., and C. W. Chambers. A Biodegradability
Test for Organic Compounds. Journal of the Water
Pollution Control Federation 39 (2): 181-187, 1967.
4. Allen, W., R. E. Derby, C. E. Garland, J. M. Peret,
W. B. Prescott, and M. Saltzman. "Determination of
Color of Water and Waste Water by Means of ADMI
Color Values." In ADMI, Dyes and The Environment:
Reports of Selected Dyes and Their Effects, Vol. I.,
American Dye Manufacturers Institute, Inc., New York,
September 1973.
99
-------
SECTION VII
PHYSICAL-CHEMICAL TREATMENT:
COAGULATION, ADSORPTION, OZONATION
In order to determine if the twenty dyeing wastewaters
could be treated by coagulation, adsorption, and chemical
oxidation, a series of laboratory-scale treatability stud-
ies was conducted. The primary objectives of the treat-
ment were decolorization of the wastes and removal of
total organic carbon (TOC). Lime, aluminum salts, and
ferric iron salts were investigated as coagulants. Dif-
ferent types of powdered activated carbon (PAC) were
investigated as adsorbents. Ozone was investigated as a
chemical oxidant. It should be emphasized that the treat-
ability analysis was carried out on a laboratory scale
only, on dyeing wastewaters generated from the dyeing
operation only, and that the objective of the study was to
determine if the wastes were treatable and, if so, by what
method and under what conditions. The results should not
be used directly to design a facility for the treatment
of segregated dyeing wastewaters at the chemical doses
given, but should serve only as a guide in selecting the
most appropriate treatment method and chemical conditions;
the actual chemical requirements must still be determined
by appropriate test procedures.
This section of the report details the procedures and re-
sults of the physical-chemical treatability studies.
PROCEDURES
Following receipt and storage of the wastes as described
in Section V, the samples were brought to room temperature.
The coagulation and powdered carbon adsorption studies
were performed using conventional jar test procedures.
The ozonation studies were performed in a small diffused
aeration column using ozone from a laboratory ozone gener-
ator.
Coagulation
In the case of lime (CaO), various amounts were weighed
out and each dose added to a 500 ml sample of the dyeing
100
-------
wastewater. A magnetic stirrer was used to flash mix each
sample until the pH stabilized, after which the sample was
stirred slowly for 30 minutes, at 35 rpm, on the jar test
apparatus. Each sample was allowed to settle for 30 min-
utes and aliquots of the supernatant were withdrawn for
subsequent ADMI color and TOG analyses by the procedures
described in Section V.
When aluminum and ferric iron were used, various amounts
of the coagulants were added from stock solutions of alum
(A12(S04)3-18 H20) and ferric chloride (FeCl3) to 500 ml
samples of the dyeing wastewaters, and each sample was
flash mixed to provide complete dispersal of the coagulant.
The pH of each sample was kept at the desired value by
concurrent addition of either Na2C03 or H2S04 during flash
mixing. Experiments were conducted at several pH values
in the pH 5 to 7 range. After flash mixing, each sample
was stirred for 30 minutes at 35 rpm and allowed to stand
quiescently for 30 minutes. After the floe settled,
aliquots were withdrawn for ADMI color and TOC analyses.
It should be mentioned that the method of adding alum or
iron to disperse dyeing wastewaters was found to be very
critical in effecting satisfactory treatment by coagula-
tion. Good flash mixing was required in order to insure
uniform dispersal of the coagulant. It was observed that
in disperse dye systems which were not properly rapid-
mixed, the concentrated coagulant solution which was added
tended to form a separate layer on top of the wastewater
and the suspension remained turbid.
Adsorption
Various amounts of powdered activated carbon (PAC) were
weighed out and added to 500 ml samples of the dyeing
wastewater. The carbon was dispersed using a magnetic
stirrer and each sample was stirred for 60 min. at 35 rpm
on the jar test apparatus to keep the PAC suspended and
to provide sufficient contact of the suspended carbon with
the wastewater. After mixing, the carbon was separated
from the wastewater by filtering the samples through
Reeve Angel glass fiber filters, and the filtrate was
analyzed for ADMI color and TOC. Experiments were repeated
using different types of powdered activated carbon, and
the effect of pH on adsorption was studied by pre-adjust-
ment of the sample pH with Na2CC>3 or H2S04 during the
rapid mix. The characteristics of the powdered carbons
investigated are given in Appendix D.
101
-------
Ozonation
Six liters of the dyeing wastewater was placed in an aera-
tion column and treated with ozone generated by passing
oxygen through a W. R. Grace and Co. ozone generator (Model
LG-2-L1). The aeration column was 4 in. in diameter and
5 ft high, fitted with a stainless steel fine mesh disc
gas diffuser. A sampling port was located 6 in. from the
bottom of the column and the liquid level of the 6 liter
sample was approximately 3 ft. After setting the roto-
meter to establish the desired gas flow rate (usually 5-10
standard cu ft/hr) using oxygen only, the ozone generator
was turned on. Samples were taken from the column at var-
ious time intervals for subsequent analysis of ADMI color,
TOG, and pH. At the conclusion of the ozonation period,
the gas flow to the column was turned off and passed via
a 3-way valve through a solution of 0.1N neutral buffered
potassium iodide solution for a specified time period
(usually 2 min.) to measure the ozone content of the gas
stream. (The pressure drop through the KI had previously
been balanced against the pressure drop through the col-
umn to insure the same gas flow rate through each system.)
The iodine formed was subsequently titrated with standard-
ized sodium thiosulfate. An example calculation for de-
termining the ozone content of the gas stream is given in
Appendix E. The experimental set-up is shown in Figure
23; all tubing and connections were stainless steel or
Teflon.
Ozonation studies were conducted on some of the wastes at
different gas flow rates and at different partial pres-
sures of ozone in the gas stream. The effect of pH was
also investigated by adjusting the pH of the 6 liter sample
with H2SC>4 or NaOH prior to ozonation. No attempt was
made to optimize gas transfer by modifying the diffuser
or the reactor configuration.
RESULTS
This section describes the results of the physical-chemical
treatability studies. The results of treating each dyeing
wastewater are reported here and overall considerations
regarding physical-chemical treatment are discussed in
Section VIII. All doses of alum are reported in mg/1 as
Al; ferric iron is reported in mg/1 as Fe; lime doses are
reported in mg/1 as CaO.
102
-------
EXHAUST
o
U)
OXYGEN
TANK
ROTOMETER
/
3-WAY
VALVE
J~L
REACTOR
•SAMPLING PORT
OZONE
GENERATOR
EXHAUST
KI TRAP
FIGURE 23. Schematic Diagram of Apparatus for Ozonation Study
-------
Dyeing Wastewater No. 1. Vat Dyes on Cotton - Exhaust
Figure 24 shows the results of treating the vat dyeing waste-
water by coagulation using lime and alum. (The initial
color of the waste sample prior to treatment by coagulation
(1,000 ADMI color units) was somewhat different than the
raw color value of the fresh waste (1910 ADMI color units)
reported in Section V, reflecting some degree of instabi-
lity of the waste during storage.) Alum effectively de-
colored the waste at a pH of 6.3 (alum coagulation is gen-
erally most effective in the pH range 5.0 to 7.0); approxi-
mately 140 mg/1 of alum (as Al) was required to decolorize
the waste to 100 color units. Lime was not as effective;
1,000 mg/1 as CaO (pH 12.0) reduced the color to only
about 350. (It should be recalled that all measurements
of color were made at pH 7.6 in accordance with the stand-
ard ADMI color procedure despite treatment at another pH
value.) The reduction in total organic carbon as a result
of coagulation by alum and lime is shown in Figure 25;
since both studies were performed on the same day, no ex-
planation for the difference in starting TOC concentra-
tions is available except that vat dyes tend to separate
from solution to some extent and a representative sample
may not have been obtained. The concentration of TOC was
reduced about 30% and 50% by 1,000 mg/1 of lime and 160
mg/1 of Al, respectively.
Powdered activated carbon (Darco HD-3000) was relatively
ineffective, with doses up to 4 g/1 at a pH of 11.1 pro-
viding no visual color change in the waste. No additional
carbon adsorption studies at lower pH values were done
for this wastewater.
Dyeing Wastewater No. 2. 1;2 Metal Complex Dye on Poly-
amide - Exhaust
Coagulation with alum provided very little color reduction.
Applications of aluminum up to 160 mg/1 at pH 6.3 reduced
the color approximately 30% to about 230. Essentially no
reduction in TOC was measured. Similarly lime, at doses
up to 1,000 mg/1 (pH 11.2), reduced the final color to
only about 230 (see Figure 26); there was no change in TOC.
Figure 26 shows the effect of powdered activated carbon
adsorption on the acid black dye waste. Nine hundred mg/1
of Nuchar D-16 decolorized the sample to a final color
value of less than 100 at pH 6.8 (the pH of the raw waste),
TOC reduction was small, as shown in Figure 27, with only
104
-------
ALUM, pH 6.3
X
200 400 600 800
LIME DOSAGE, mg/I
1000
LJ
0
25 50 75 100 125
ALUM DOSAGE,mg/1 as Al
150
FIGURE 24. Dyeing Wastewater No. 1 (Vat Dyes on Cotton)
Decolorization by Lime and Alum Coagulation
105
-------
300 -
o>
§ 200
tr
<
o
o
z
<
o
o:
o
o 100
P a
0
\,
ALUM, pH 6.3
\
1
200 400 600 800
LIME DOSAGE, mg/l
1000 1200
0 25 50 75 100 125 150 175 200
ALUM DOSAGE,mg/l as Al
FIGURE 25. Dyeing Wastewater No. 1 (Vat Dyes on Cotton):
Total Organic Carbon Reduction by Lime and Alum
Coagulation
106
-------
350
NUCHAR D-16
50 h
I I I I
0 200 400 600 800 1000 1200
LIME OR POWDERED ACTIVATED CARBON DOSAGE, mg/l
FIGURE 26. Dyeing Wastewater No. 2 (1:2 Metal Complex Dye
on Polyamide): Decolorization by Lime and
Powdered Activated Carbon Adsorption
107
-------
400
1*300
O
GO
a:
<
o
o
z
200
a:
o
100
0
o
o
NUCHAR D-16, pH 6.8
200 400 600 800 1000 1200
POWDERED ACTIVATED CARBON DOSAGE, mg/I
FIGURE 27. Dyeing Wastewater No. 2 (1:2 Metal Complex on
Polyamide): Removal of Total Organic Carbon by
Powdered Activated Carbon
108
-------
a 20% reduction in TOC resulting from the application of
1,000 mg/1 of Nuchar D-16, suggesting that the dye is signi-
ficantly more strongly adsorbed than the other organic com-
ponents of the dye bath.
Ozone was found to effectively decolorize the waste as shown
in Figure 28. The application of only 800 mg of ozone
(approximately 130 mg/1) was sufficient to decolorize the
sample to less than 100. The pH dropped slightly from 7.9
to 7.6 during the 20 minute treatment, but TOC remained
virtually unchanged. (The low ozone yield of 1.8% 03 by
volume was due to a leak in the generator which was sub-
sequently repaired,)
Dyeing Wastewater No. 3. Disperse Dyes on Polyester - Ex-
haust
Figure 29 shows the effect of coagulation in decolorizing
the disperse dyeing wastewater. Alum was very effective,
with doses of approximately 60 mg/1 of Al reducing the
color to less than 50 at a pH of 5. Coagulation studies
were also conducted at pH 6 and pH 7 with the results at
pH 6 being very similar to those shown for pH 7 (see also
Table 50); it is apparent that alum performs more effect-
ively at pH 5. Tests at pH values below 5 showed little
apparent reduction in color. Ferric iron was also rela-
tively effective in decoloring the disperse dyeing waste-
water; 260 mg/1 of Fe(III) was sufficient to reduce the
color of the waste to less than 50 at a pH of 5. In the
case of iron, however, when the system was underdosed, an
enhancement in color was measured due to the presence of
reddish-brown colloidal particles of ferric hydroxide.
Iron was also less efficient at higher pH's as shown by
Table 50. Lime gave no apparent change in color at dosages
up to 1,000 mg/1 (pH 11.9). TOC was reduced approximately
50-60% at Al and Fe(III) dosages of 160 and 340 mg/1,
respectively (see Table 50); TOC removal with iron was
slightly better than with aluminum. No TOC reduction was
observed when lime was used.
Application of powdered activated carbon (Nuchar D-16 at
pH 7.8, the pH of the raw dye waste) gave no apparent
decolorization at doses up to 1200 mg/1.
Figure 30 shows the results of ozonating the disperse dye-
ing wastewater. Relatively poor decolorization was ob<-
served; even after the application of 37 gm of ozone
(approximately 6 gm/1), the color was reduced by only
109
-------
300
1.8% 03
6.5 Scfh
pH 7.9-7.6
I 2
OZONE APPLIED, gms
FIGURE 28. Dyeing Wastewater No. 2 (1:2 Metal Complex Dye
on Polyamide): Decolorization by Ozone
110
-------
400
300
UJ
^
i
200
8
Q
<
100
ALUM, pH 5.0*
Fe(ni), pH5.0
ALUM,
pH7.0
1
1
Q
I
O
J I
0
I
25 50 75 100 125
ALUM DOSAGE,mg/1 as Al
I I I I I
150
U
0 50 100 150 200 250 300
IRON (IE) DOS AGE, mg/1 as Fe
350
FIGURE 29. Dyeing Wastewater No. 3 (Disperse Dyes on Poly-
ester) : Decolorization by Alum and Iron
(III) Coagul'ation
-------
TABLE 50, EFFECT OF pH ON COAGULATION OF DYEING WASTE-
WATER NO. 3 (DISPERSE DYES ON POLYESTER) BY
ALUM AND FERRIC CHLORIDE
Alum
dose,
mg/1
as Al
0
31
61
90
117
157
PH
ADMI
color
306
310
172
27
43
34
7a
TOC,
mg/1
308
274
215
176
152
134
pH
ADMI
color
324
350
149
19
36
23
6a
TOC,
mg/1
321
315
185
175
160
150
PH
ADMI
color
345
375
43
26
20
28
5a
TOC,
mg/1
305
297
173
159
167
159
Fe(III)
dose,
mg/1
as Fe
0
67
132
195
255
341
pH
ADMI
color
387
545
70
27
6a
TOC,
mg/1
300
296
280
188
148
133
pH
ADMI
color
313
261
47
37
5a
TOC,
mg/1
294
302
281
153
127
114
maintained constant by concurrent addition of acid or base with the coagulant.
-------
400
300
UJ
ID
cr
3200
o
o
100
0
6.3% 03
7 Scfh
pH 7.9-6.9
1
1
10 20 30
OZONE APPLIED,gms
40
FIGURE 30. Dyeing Wastewater No. 3 (Disperse Dyes on Poly-
ester) : Decolorization by Ozone
113
-------
about 55%, The Figure aiso shows a significant lag period
before any appreciable decolorization takes place. The pH
dropped somewhat during treatment and there was no measur-
able change in TOC,
Dyeing Wastewater No. 4. After-Copperable Direct Dye on
Cotton - Exhaust
The after-treatable direct dyeing wastewater was a rela-
tively turbid sample (the concentration of suspended
solids was 41 mg/1), with most of the color associated
with the suspended particles in the waste. As reported in
Section V, prefiltration of the sample with Celite removed
most of the color and, as a result, the data reported
herein are for samples analyzed by the ADMI color proce-
dure in which the prefiltration step was omitted. Although
some of the colored particles settled out of the sample
upon standing, an appreciable quantity of colloidal parti-
cles with their associated color still remained and it
appeared that coagulation would be the best treatment
alternative. Figure 31 shows the results of coagulating
the waste with alum and with lime. The ordinate, i.e.,
"apparent" color, is an indication of the visual appearance
of the sample, but it must be recalled that this apparent
color value includes light scattering due to suspended
particulates as well as the absorbance of light by the dye
molecules and copper salts. Lime, at doses up to 200 mg/1
(pH 11,1), resulted in decolorization of the waste to an
apparent color of about 120. The resulting floe settled
more slowly than the floe formed by alum. Coagulation
with alum resulted in decolorization of the waste to an
apparent color of less than 100 at an aluminum dosage of
16 mg/1 at pH 6.0. Coagulation with alum at pH 6 gave
appreciably better results than coagulation at pH 7. In-
creasing doses of alum also resulted in better-settling
floe. The removal of TOC by alum and lime was small as
shown in Figure 32. There was no reduction in BOD follow-
ing the application of 16 mg/1 of aluminum at pH 6.
Figure 33 shows the effect of ozone on the after-copperable
direct dyeing wastewater. Ozone was fairly efficient in
decolorizing the blue waste, with 2.5 gms of ozone (approx-
imately 400 mg/1) reducing the apparent color to less than
100. pH remained constant throughout the ozonation period.
There was no measurable change in TOC.
114
-------
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Dyeing Wastewater No, 5. Reactive Dye on Cotton - Exhaust
The reactive dyeing wastewater had an intense red color,
as reflected by its high ADMI color value of 3890. Coagu-
lation of the waste with alum was relatively ineffective
as shown in Figure 34; 160 mg/1 of Al(III) reduced the ADMI
color to 635 at pH 5 but the color could not be reduced
any further by additional Al(III) dosages up to 450 mg/1.
Treatment by alum at pH 7 gave no decolorization at a
dosage of 160 mg/1. Figure 34 shows a reduction of TOC by
alum of approximately 30-50% at pH 5 depending upon the
alum dose; there was no change in TOC at pH 7 as shown.
Application of lime at doses up to 3000 mg/1 (pH 11,8) gave
no measurable reduction in color.
Activated carbon was particularly effective in decoloring
the reactive dye, but large doses of the carbon were re-
quired as indicated in Figure 35. The adsorption studies
were conducted at three different pH values, as shown,
using Darco HD-3000. Best results were obtained at pH 3.5
(the raw dye waste had a pH of 11.2); approximately 2000
mg/1 reduced the ADMI color value to 100. Higher carbon
doses were required at pH 10.7 and pH 7 as shown. The
removal of TOC by carbon was also quite effective as shown
in Figure 36, again with increased removal obtained at the
more acidic pH value; 2000 mg/1 of HD-3000 at pH 3.5 reduced
the TOC concentration by 80% to 28 mg/1. The discrepancy
in the initial TOC concentrations in Figure 36 could not
be explained.
The reactive red dye was decolorized quite well by ozone
as shown in Figure 37; an application of 6 gms of ozone
(approximately 1 gm/1) resulted in decolorization to less
than 100 color units at a pH of 10.6. Despite the lower
percentage of ozone in the gas stream at pH 10.6 than at
pH 2.0, decolorization was more effective at the higher
pH value. (The ozone generator still leaked considerably
as evidenced by the low ozone yields.) A third sample,
at pH 8, was also decolorized less effectively than at
pH 10.7. The concentration of TOC was unchanged by the
ozone treatment.
Dyeing Wastewater No. 6. Disperse Dyes on Polyamide Car-
pet - Exhaust
Figure 38 shows the effect of lime and alum in coagulating
the disperse dyeing wastewater; the waste was relatively
uncolored, having an ADMI color value of 100, Following
118
-------
ADMI COLOR VALUE
.H
O
G
5d
M
Co
O 0
o ^<
M CD
o H-
3 5!
& .QJ
cn
H rt
O (D
n- s;
o o
M rt
(D
IQ a
0) O
,
o 01
o ->
OJ »
t-i 0)
tr o
o o
3 rt
H-
.» <
(D (D
OJ CD
I-1
O
tr s
*<
o
> 0
h-1 rt
C rt
3 O
3
TOTAL ORGANIC CARBON, mg/l
-------
4000
DARCO HD-3000
0 500 1000 1500 2000 2500
POWDERED ACTIVATED CARBON DOSAGE, mg/l
FIGURE 35. Dyeing Wastewater No. 5 (Reactive Dye on Cotton):
Decolorization by Powdered activated Carbon
Adsorption
120
-------
DARCO HD-3000
0 1000 2000 3000 4000
POWDERED ACTIVATED CARBON DOSAGE,mg/l
FIGURE 36, Dyeing Wastewater No. 5 (Reactive Dye on Cotton):
Total Organic Carbon Removal by Powdered Activated
Carbon
121
-------
5000
2000
ujlOOO
ID
O 500
O
o
o
<
200
100
50
0
0.6% 03
7.2 Scfh
pH 10.6
2.8% 03
7.4 Scfh
pH 2.0
D
4 8
OZONE APPLIED,gms
12
FIGURE 37. Dyeing Wastewater No, 5 (Reactive Dye on Cotton)
Decolorization by Ozone
122
-------
150
100 150
LIME DOSAGE ,mg/1
I
200
250
0
10 20 30
ALUM DOSAGE,mg/1 as Al
40
FIGURE 38. Dyeing Wastewater No. 6 (Disperse Dyes on Poly-
amide Carpet): Color Removal by Lime and Alum
Coagulation .. „_
-------
an initial apparent enhancement of the color, presumably
due to the formation of colloidal aluminum hydroxide which
was not completely separated by the Celite prefiltration
step, 30 mg/1 of aluminum at pH 7,0 decolorized the waste
to a value of 50, with increased dosages reducing the
color even further. TOG was reduced about 20% by this dos-
age. Lime effectively decolorized the waste with a dosage
of 200 mg/1 (pH 11.5) reducing the ADMI color to 50. Addi-
tion of the lime turned the samples from orange to pink,
but upon readjustment of the pH to 7.6 as required in the
ADMI color procedure, the samples converted to a light
yellow-green color. No floe were observed as a result of
the lime addition but the color was lessened as indicated
in the Figure. TOC was only slightly reduced, by about
15-20%. The final BOD5 of the waste following treatment
by 30 mg/1 of alum was 6 mg/1, down from an initial value
of 78 mg/1.
Two hundred mg/1 of Darco HD-3000 decolorized the waste to
a value of 65 at pH 8.2 as shown in Figure 39. One thou-
sand mg/1 of the powdered carbon reduced the TOC by about
50% to 62 mg/1.
Ozonation of the sample was not investigated due to the
very low color value of the raw wastewater,
Dyeing Wastewater No. 7. Acid Chrome Dye on Wool - Exhaust
The color of the acid-chrome dyeing wastewater can be
attributed to two components: the mordant black 11 dye and
Cr(VI). Measurement of the chromium content of the raw
waste by atomic absorption analysis indicated the presence
of 37.5 mg/1 of total chromium, a good portion of which
presumably was in the +VI oxidation state since the dyeing
procedure calls for the addition of sodium dichromate.
The fact that both lime and alum were ineffective in de-
colorizing the waste at dosages up to 2000 and 160 mg/1,
respectively, supports this presumption; chromium (III)
is relatively insoluble at neutral pH values and should
have been quite readily coagulated as Cr(OH)3 by the lime
or alum treatment. Lime and alum both improved the clarity
of the waste (the initial sample was dark brown with some
turbidity) but the treated sample had an intense yellow-
orange color.
Darco HD-3000 was able to decolorize the waste but only at
extremely high dosages as shown in Figure 40. Decoloriza-
tion was most effective at acidic pH values as shown, with
124
-------
150
TOC
Q
DARCO HD-3000, pH 8.2
I
1
I
I
150
100.
o>
O
CD
O
O
e>
or
O
50^
O
FIGURE 39.
200 400 600 800 1000
POWDERED ACTIVATED CARBON DOSAGE,mg/l
Dyeing Wastewater No, 6 (Disperse Dye on Poly-
amide Carpet): Color and Total Organic Removal
by Powdered Activated Carbon
0
125
-------
4000
3000
LJ
ID
3
02000
_i
o
o
o
<
DARCO HD-3000
1000 -
0 1000 2000 3000 4000
POWDERED ACTIVATED CARBON DOSAGE, mg/I
FIGURE 40, Dyeing Wastewater No, 7 (Acid-Chrome Dye on
Wool): Decolorization by Powdered Activated
Carbon
126
-------
4 gm/1 of HD.-3QQQ at pH 4,2 (.the pH of, the raw waste) re-
ducing the color to 75, Decolorization was probably a
result of reduction of the hexavalent chromium by the acti-
vated carbon, the carbon serving as a reducing agent. The
residual chromium(III) was either adsorbed and removed on
the carbon surface, or precipitated as insoluble chromium
hydroxide, Cr(OH)3, and was separated along with the pow-
dered carbon. The mordant black dye was also apparently
adsorbed as evidenced by the disappearance of the black
color and the low final color value.
Since most of the color of the acid-chrome dyeing waste-
water was believed to be due to the residual Cr(VI), appli-
cation of a reducing agent (ferrous iron) was attempted.
The waste was acidified to pH 3 with sulfuric acid and
various dosages of Fe(II), as ferrous sulfate, were added,
A contact period of 10 minutes was provided between the
ferrous iron and the waste at pH 3, after which lime was
added to raise the pH to 7 and the treated sample was al-
lowed to settle for 30 min. The residual ADMI color value
as a function of added Fe(II) is shown in Figure 41. The
optimal dose of about 180 mg/1 of Fe(II) corresponds to a
theoretical Cr(VI) concentration of approximately 55 mg/1
(on the basis of a 3:1 molar stoichiometry of iron to
chromium (see Table 51). The residual color was probably
due to the mordant black dye and the waste could probably
have been decolorized further by the application of acti-
vated carbon, but at much lower dosages than given above.
The addition of activated carbon prior to reduction of the
chromium by ferrous iron is an expensive way of removing
Cr(VI). The acidification-reduction-neutralization treat-
ment resulted in a reduction in TOC of about 40% as shown
in Figure 42, but BOD was unchanged.
Dyeing Wastewater No. 8. Basic Dye on Polyacrylic — Exhaust
As indicated in Section V, an appreciable amount of the
basic dye was removed when the waste was prefiltered by
Celite prior to the ADMI color analysis. Consequently, the
Celite filtration step was omitted when residual color was
measured. Lime and alum resulted in no measurable color
reduction at dosages up to 2000 and 315 mg/1, respectively.
TOC reduction in both cases was also small.
The basic dye was effectively decolorized by activated
carbon adsorption as demonstrated in Figure 43. Various
types of powdered carbon were investigated, and the effect
of pH was also examined. Table 52 shows the effect of pH
127
-------
> 100 200 300
IRON (E) DOSAGE,mg/l as Fe
FIGURE 41t Dyeing Wastewater No. 7 (Acid-Chrome Dye on
Wool); Removal of Color by Acidification,
Iron(II) Reduction, Neutralization
128
400
-------
250
100 200 300
IRON (H) DOSAGE, mg/l as Fe
400
FIGURE 42, Dyeing Wastewater No.. 7 (Acid-Chrome Dye on Wool)
Total Organic Carbon Removal by Acidification,
Iron(II) Addition, Neutralization
129
-------
:H
O
LO
O
O M O
fl) H-^
h o n>
O «• 3
3 'Q
O
n> s!
O (D
o en
M rt
O 0)
H" Q)
N rt
0) (D
rt H
H-
O 2
3 O
CX5
o w
s: &
& 0)
(D H-
H O
n>
& o
> n>
o
rt O
H- 3
<
SU *0
rt O
CD M
O
Ol
O
APPARENT ADMI COLOR VALUE
— ro
— ro 01 o o
o o o o o
o o o o o
CJI
o
o
o
o
*•
o
o
o
ro
p
o
o
o
-------
TABLE 51, EFFECT OF IRON(II) REDUCTION3 ON
DYEING WASTEWATER NO. 7 (ACID-CHROME DYE)
Fe(II)
dosage,
mg/1
0
49
126
184
224
290
360
405
Theoretical
Cr(VI)
reduced.
mg/1
0
15
39
57
69
89
111
125
ADMI
color
value
948
488
322
144
166
123
120
128
awastewater was acidified to pH 3 with
treated with Fe(II), neutralized with lime,
and settled.
on decolorization of the waste by 1500 mg/1 of Darco HD-
3000; it is apparent that pH 4.5 (the initial pH of the raw
waste) is most effective for decolorization. Table 53 shows
the effect of different grades of powdered carbon at applied
dosages of 1500 mg/1 and pH 4.5. The two Nuchar grades and
Darco KB are seen to be equally effective in decolorizing
the waste sample. Figure 43 shows the reduction in apparent
ADMI color as a function of carbon dosage for the Nuchar
D-16 and Darco HD-3000 at pH 4.5; 1000 mg/1 of the Nuchar
reduced the color to less than 100. Presumably the same
degree of treatment could be achieved with Darco KB in accor-
dance with the results in Table 53. TOC removal by 1000 mg/1
of Nuchar D-16 was about 40% as shown in Figure 44. BOD
removal was approximately 30%.
Decolorization of the basic dyeing wastewater by ozone is
shown in Figure 45. Ozonation resulted in a reduction in
pH of the waste. Despite the lower partial pressure of
ozone in the more acidic sample, ozone is more efficient in
decolorizing the waste at the lower pH, This was apparent-
ly due to the longer lag exhibited by the pH 7,6 sample.
(A lag was not observed for the pH 4.1 sample, but this
131
-------
TABLE 52. EFFECT OF pH ON TREATMENT OF DYEING WASTEWATER
NO, 8 (BASIC DYE ON POLYACRYLIC) BY POWDERED ACTIVATED
CARBON
Dosage of
DARCO
HD-3000,
mg/1
1500
1500
1500
1500
1500
1500
pH
2.0
2.7
3.7
4.5
5
6
TOC,
mg/1
148
144
134
134
138
144
Apparent ADMI
color value
204
205
202
141
186
212
TABLE 53. EFFECT OF DIFFERENT TYPES OF POWDERED ACTIVATED
CARBONS ON TREATMENT OF DYEING WASTEWATER NO. 8 (BASIC DYE
ON POLYACRYLIC) AT pH 4.5
Type of
powdered
carbon
DARCO HDB
DARCO S-51
DARCO KB
DARCO HD-3000
NUCHAR D-14
NUCHAR D-16
Dosage,
mg/1
1500
1500
1500
1500
1500
1500
pH
4.5
4.5
4.5
4.5
4.5
4,5
TOC,
mg/1
132
142
108
140
134
125
Apparent
ADMI color
value
147
207
66
153
62
76
132
-------
300
NUCHAR
pH 4.5
500 1000 1500 2000
POWDERED ACTIVATED CARBON DOSAGE, mg/I
FIGURE 44, Dyeing Wastewater No. 8 (Basic Dye on Polyacry-
lic): Total Organic Carbon Removal by Powdered
Activated Carbon
133
-------
h]
H
o
a
APPARENT ADMI COLOR VALUE
ro
U)
-------
may have been due to the relatively long interval before
the .first aliquot was removed.) Decolorization was quite
effective, with the color reduced from. 12,000 to 500 by
the application of 6 gms of ozone (! gm/ll, but the appar^
ent color could not be reduced below 200. There was no
reduction in the TOC of the waste as a result of ozonation,
but the BOD5 was observed to increase from 160 to 270- mg/1.
Dyeing Wastewater No. 9. Disperse Dyes on Polyester Car-
pet - Exhaust
This waste was highly turbid (suspended solids concentra-
tion of 101 mg/1) and filtration of the samples was re-
quired prior to the color analyses. However, to avoid a
significant loss in color as a result of adsorption by
Celite, the treated samples were simply filtered through
Reeve-Angel paper to eliminate the turbidity without affect-
ing the apparent color of the aliquots. The ADMI color
analysis was performed on these prefiltered samples.
Lime and alum effectively coagulated the disperse dyeing
wastewater as shown in Figure 46; 1000 mg/1 of lime (pH
11.9) reduced the apparent color to 132. In the case of
alum, initial enhancement of the apparent "color" was mea-
sured, presumably due to the formation of colloidal alum-
inum hydroxide which was not satisfactorily removed by the
Reeve-Angel prefiltration. At higher doses, however, alum
proved to be an effective coagulant for this waste, with
a dosage of 150 mg/1 of Al reducing the apparent color to
80. pH 5 again was more effective for alum coagulation
than pH 7. At the lower alum doses, the aluminum hydroxide
floe settled rather poorly but at dosages of 125 and 150
mg/1 good-settling floe resulted. TOC removal by alum was
good with reductions of about 60% resulting from the appli-
cation of 160 mg/1 of aluminum at pH 5 (see Figure 47) .
TOC removal by lime was about 20%. The final BOD^ after
treatment with 160 mg/1 of Al(III) at pH 5 was 60 mg/1,
a reduction of about 65%.
Nuchar D-16, at dosages up to 2000 mg/1, at pH 7.1, gave
no measurable reduction in color. TOC, however, was re-
duced approximately 70% by 2000 mg/1 of the Nuchar carbon.
Decolorization of the disperse dyeing wastewater by ozone
is shown in Figure 48. Under conditions of neutral pH, a
lag was observed after which 24 gms of ozone (4 gms/1) was
required to decolorize the waste to less than 100. Under
acidic conditions, only 15 gms (2.5 gms/1) was able to
135
-------
APPARENT ADMI COLOR VALUE
U)
en
a
10
^ ^ o
M O ^
C H- fl>
3 ^ H-
fD 3
O rt
0J (D 5!
U3 HJ pj
C CO
I-1 O rt
O (D rt
3 rt (D
— ^
2
O O
O -
3
O
<
H-
0)
hi
cn
(D
a
^<
(D
0)
3
O
3
ro
C71
o
o
m
«•
03
Ol
O1
O
-------
300
250
ALUM, pH 5
o
o 150
o
-i 100
50
LIME
NUCHAR D-16
pH 7.1
I
1
I
I
0 200 400 600 800 1000
LIME OR POWDERED ACTIVATED CARBON DOSAGE, mg/l
I I I I I \ I I
0
25 50 75 100 125
ALUM DOSAGE,mg/l as Al
150
FIGURE 47, Dyeing Wastewater No, 9 (Disperse Dyes on Poly-
ester Carpet): Removal of Total Organic Carbon
by Lime, Alum and Powdered Activated Carbon
137
-------
00
00
htj
:n
O
G
»
W
00
APPARENT ADMI COLOR VALUE
CD D
W *•<
ft fD
CD
o
fu S!
h( pj
^ tn
CD rt
ft CD
rt
D CD
CD 'h
O
O 21
M O
O *
1-1
H- VD
N
OJ ^
rt D
H- H-
O tn
S t3
CD
cr h
*< tn
CD
O
N a
o ^
3 CD
CD tn
O
M
^<
I
-------
achieve the same degree of decolorization. No change in
TOG was measured but, again, the BOD5 increased as a result
of ozonation from an initial concentration of 80 mg/1 to
a final concentration for both samples of approximately
105 mg/1. (It should be noted that the initial concentra-
tions of TOG and BOD5, and the initial color of dyeing
wastewater no. 9 immediately prior to ozone treatment were
somewhat less than the initial values of the fresh waste.
Apparently a change in the composition of the waste had
taken place during storage.)
Dyeing Wastewater No. 10. Acid Dye on Polyamide - Exhaust
Alum and lime were relatively ineffective in decolorizing
the acid dye. Alum, at pH 7, at doses up to 160 mg/1 of
Al reduced the ADMI color from 4000 to 2150 and the TOG
from 315 to 160 mg/1 as shown in Figure 49. Lime provided
a similar degree of decolorization to 2140 at a dosage of
1000 mg/1 (pH 11.8) but no apparent formation of floe was
observed. In the case of lime, decolorization was appar-
ently due to a complexation effect which altered the color
of the sample. There was no removal of TOG with 1000 mg/1
of lime. By comparison, alum resulted in a good-settling
floe, but decolorization was still not very effective.
Table 54 shows the effect of 1000 mg/1 of Darco HD-3000 on
the acid dyeing wastewater at various pH values, showing
that pH 5.1 (the initial pH of the waste) was most effect-
ive .for decolorizing the waste. Table 55 shows the effect
of 900 mg/1 of several different grades of powdered carbon
on the color of the waste at pH 5.1. Darco HDB and KB,
and Nuchar D-14 and D-16 were significantly more effective
than Darco HD-3000. Figure 50 shows the effect of dif-
ferent doses of three types of carbons on the color of the
acid dyeing wastewater. Decolorization was fairly effect-
ive, with 1000 mg/1 of all three carbons reducing the
color of the waste to about 260. Increasing doses, how-
ever, brought about very little additional decolorization,
with the color leveling off at approximately 200. The TOG
was reduced approximately 35% by the application of 1000
mg/1 of Darco KB as shown in Figure 51; KB was more ef-
fective than HD-3000. The BOD5 was also reduced approxi-
mately 35% to a final value of 150 mg/1. Figure 85a and
the companion Table 67 (presented at the end of this sec-
tion) shows the appearance of the acid dyeing wastewater
after various doses of Darco HD-3000. The blue color ap-
pears to be essentially removed by about 1000 to 1200 mg/1
of carbon, but the residual greyish color appears to be
resistant to subsequent decolorization by additional doses
of carbon.
139
-------
4000
3000
LJ
13
a:
32000
8
2
o
1000
TOC
D •
pH 7.0
1
400
300 _
V.
e
o
OQ
CC
O
200o
o
a:
o
100
25 50 75 100 125
ALUM DOSAGE, mg/I as Al
150
FIGURE 49. Dyeing Wastewater No. 10 (Acid Dye on Polyamide):
Color and Total Organic Carbon Removal by Alum
Coagulation
140
-------
TABLE 54, EFFECT OF pH ON TREATMENT OF DYEING WASTEWATER
NO. 10 (ACID DYE ON POLYAMIDE) BY POWDERED ACTIVATED CARBON
Dosage of
DARCO
HD-3000,
mg/1
1000
1000
1000
1000
1000
pH
2
2.3
3.8
5.1
6.0
TOC,
mg/1
196
178
182
208
246
ADMI
color
value
322
329
306
270
425
TABLE 55. EFFECT OF DIFFERENT TYPES OF POWDERED ACTIVATED
CARBONS ON TREATMENT OF DYEING WASTEWATER NO. 10 (ACID DYE
ON POLYAMIDE) AT pH 5.1
Type of
powdered
carbon
DARCO HD-3000
DARCO HDB
DARCO KB
NUCHAR D-14
NUCHAR D-16
Dosage,
mg/1
900
900
900
900
900
PH
5.1
5,1
5.1
5,1
5,1
ADMI
color
value
649
312
338
227
298
141
-------
10,000
5000 h
4000
3000 h
HYDRODARCO 3000
A-0<
NUCHAR D-14
100
200 400 600 800 1000
POWDERED ACTIVATED CARBON DOSAGE, mg/l
FIGURE 50. Dyeing Wastewater No. 10 (Acid Dye on Polyamide)
Decolorization by Powdered Activated Carbon
142
-------
300!
250
200
o
m
o
150
o:
o
100
50
0
\ DARCO HD-3000
\
DARCO KB
pH 5.1
1
I
1
I
0 200 400 600 800 1000
POWDERED ACTIVATED CARBON DOSAGE,mg/l
FIGURE 51, Dyeing Wastewater No, 10 (Acid Dye on Polyamide)
Removal of Total Organic Carbon by Powdered
Activated Carbon
143
-------
Similar results were observed by ozonation of the
dyeing wa,stewa,ter•„ &s shown in Figujre 52 f the waste is
decolorized to a, fair extent by ozone but the reduction in
color seemed to be leveling off at about 400 (_see also
Figure 85b at the end of this section). The pH of the
sample decreased from 6,6 to 3,5 by ozonation,, There was
no change in TOC but again the BOD^ of the waste increased
as a result of ozone treatment.
Dyeing Wastewater No. 11. Direct Dye on Rayon - Exhaust
The direct black dyeing wastewater was very intensely color^
ed as reflected by the initial color value of 12,500,
Lime was ineffective, with no apparent color removal at
dosages up to 3000 mg/1 (pH 12.3). The TOC concentration
was reduced by 25% by this dosage of lime. Al(III) de-
creased the color to 2000 at a dosage of 30 mg/1 at pH 5,
but further alum addition resulted in no further decolori-
zation as shown in Figure 53 and Table 56. Following alum
treatment, the sample appeared red in color as shown in
Figure 85c. TOC was reduced by the 30 mg/1 application
of aluminum to 27 mg/1, in effect an 80% reduction from
the initial TOC value (see Figure 54). Powdered activated
carbon by itself was ineffective in decolorizing the waste
or in removing TOC, with applications of 2000 mg/1 of Nuchar
D-14 at a pH of 6.6 resulting in no measurable reduction
in color or TOC. However, when activated carbon was cou-
pled with alum coagulation, decolorization was quite effec-
tive as shown in Figure 53 and Table 56. The direct dye-
ing wastewater was coagulated with 30 mg/1 of aluminum at
pH 5 and allowed to settle. The residual supernatant was
then treated with various doses of Nuchar D-14 powdered
carbon. Six hundred mg/1 of the carbon was sufficient to
decolorize the waste to a final color value of 34 and to
reduce the TOC concentration to 3 mg/1. Figure 85c shows
the effectiveness of the alum treatment coupled with the
subsequent addition of powdered activated carbon. The
final BOD5 was less than 1 mg/1.
Ozonation was relatively ineffective in decolorizing the
direct dyeing wastewater. Although the color was substan-
tially reduced by ozone (see Figure 55), the application
of 28 gms of ozone (.about 4.5 gms/1) still left a residual
color greater than 1100. The reaction was somewhat faster
when the pH was elevated by the addition of a base, but
ozonation caused the pH to decrease significantly. Figure
85d shows the colors of the samples at various stages of
the ozone treatment. TOC was reduced slightly to 130 mg/1
but the BOD5 increased,
144
-------
1800,
1600
1400
1200
LJ
ID
1000
o
o
800
600
400
200
0
4.8% 03
7 Scfh
pH 6.6-3.5
1
10 15
OZONE APPLIED,gms
20
25
FIGURE 52. Dyeing Wastewater No, 10 (Acid Dye on Polyamide)
Decolorization by Ozone
145
-------
20,000 -
ALUM ALONE, NO PAC
30 mg/l ALUM + PAC
LT
I
1
1
1
25
50 75 100 125
ALUM DOSAGE, mg/l
I I I
I5O 175
I
U
0 200 400 600 800 1000
POWDERED ACTIVATED CARBON DOSAGE, mg/l
FIGURE 53. Dyeing Wastewater No, 11 (Direct Dye on Rayon):
Decolorization by Alum Coagulation Alone and by
Two-Stage Sequence Involving Alum Coagulation
and Powdered Activated Carbon Adsorption
146
-------
NUCHAR D-14, pH 6.6
200 400 600 800 1000
POWDERED ACTIVATED CARBON DOSAGE, mg/I
I I I I I I I
25 50 75 100 125
ALUM DOSAGE, mg/I as Al
150
FIGURE 54. Dyeing Wastewater No, 11 (Direct Dye on Rayon):
Removal of Total Organic Carbon by Alum Coagu-
lation or Powdered Activated Carbon Adsorption
147
-------
12,000
10,000 -
10 15 20
OZONE APPLIED, gms
FIGURE 55. Dyeing Wastewater No, 11 (Direct Dye on Rayon):
Decolorization by Ozone
148
-------
TABLE 56. EFFECT OF ALUM AND POWDERED ACTIVATED CARBON ON
TREATMENT OF DYEING WASTEWATER NO. 11 (DIRECT DYE ON RAYON)
Al(III)
dosage ,
rag/1
0
16
32
64
32
32
32
32
0
PAG**
dosage/
mg/1
0
0
0
0
0
400
500
600
2000
PH
6.6
5.0
5.0
5,0
5.0
5.0
5.0
5.0
6.6
TOC,
mg/1
171
159
27
28
27
7
,-- ~
3
148
ADMI
color
11 f 050
7,920
1,975
2,029
1,975
186
97
34
10,915
NUCHAR D-14
Dyeing Wastewater No,
Exhaust
12. Direct Developed Dye on Rayon
Coagulation of the direct developed dyeing wastewater with
alum provided a significant degree of decolorization at
low doses, but higher doses had no additional effect on
color removal as shown in Figure 56 and Table 57. Alum
at pH 5 was more effective than at pH 7, but the color
could not be reduced below 300 by Al(lll). Similar results
were observed with lime as shown in Figure 57, with 400
mg/1 (pH 11.8) reducing the color to 300 below which no
further appreciable decolorization occurred. It should be
noted that the addition of lime resulted in a floe which
settled poorly. The application of powdered activated
carbon (Nuchar D-14) at doses up to 1000 mg/1 at pH 3.1
gave no measurable color reduction, but, as in the case of
dyeing wastewater no. 11, when the PAC was coupled with
coagulation, the resulting treatment was very effective.
Eight mg/1 of alum, as Al, was applied to the waste at pH
5 and, following mixing and settling, the supernatant was
withdrawn and treated by various doses of Nuchar D-14, Fig-
149
-------
3000
2000
ALUM ALONE, pH 7
NVLUM ALONE, pH 5
8 mg/l ALUM + PAC, pH 5
A
I
1
I
1
1
20 30 40 50 60 70 80
ALUM DOSAGE,mg/l as A!
I I I I I
0 200 400 600 800
POWDERED ACTIVATED CARBON DOSAGE, mg/l
FIGURE 56, Dyeing Wastewater No. 12 (Direct Developed Dye
on Rayon): Color Removal by Alum Coagulation
Alone and by Two-Stage Sequence Involving Alum
Coagulation and Powdered Activated Carbon Adsorp-
tion
150
-------
5000
2000 -
UJ
ID
_J
§
3
O
o
o
<
1000 -
500
200 -
100 -
300
600 900 1200
LIME DOSAGE,mg/l
1500
FIGURE 57. Dyeing Wastewater No. 12 (Direct Developed Dye
on Rayon): Decolorization by Lime
151
-------
57, EFFECT OF ALUM AND POWDERED ACTIVATED CARBON ON
TREATMENT OF DYEING WASTEWATER NO, 12 (DIRECT DEVELOPED
DYE ON RAYON)
A1CIII)
dosage,
mg/1
0
5
8
16
8
8
8
8
8
0
PACa
dosage,
mg/1
0
0
0
0
0
100
200
300
400
1000
pH
3,2
5.0
5,0
5.0
5.1
5.1
5.1
5.1
5.1
3.1
TOC,
mg/1
56
29
23
19
20
17
6
2
3
29
ADMI
color
2730
290
282
279
284
169
98
78
66
2389
NUCHAR D-14
ure 56 and Table 57 show the results of the combined treat-
ment; the two stage treatment consisting of 8 mg/1 of alum-
inum and 200 mg/1 of PAC reduced the color below 100 and
the TOC to 6 mg/1. Additional color removal was observed
at higher carbon doses. The final BOD^ was 1 mg/1.
Ozonation also proved to be an effective method of treating
the direct developed dyeing wastewater as shown in Figures
58 and 59. Figure 58 shows that pH has very little effect
on the treatment of the waste; the rates of decolorization
appear to be parallel, the only difference being that the
sample at pH 3,5 had a higher initial color than the sample
at pH 6.7, The two runs were made on different days and
apparently there was some change in the color of the sample
during storage. Figure 59 shows that the partial pressure
152
-------
1600
f
u|200
_j
§
cr
3
O
O
800
01
U)
O
<
400
5.3% 03
7 Scfh
3.5
4.9% 0
7 Scfh
pH 6.7
1600
1200'
800
400
3.9% 03
10 Scfh
pH 3.0
\
5.7% 03\
5 Scfh
pH 3.0
I
10
20
30 0
OZONE APPLIED, gms
10
20
30
FIGURE 58. Dyeing Wastewater No. 12
(Direct Developed Dye on
Rayon): Effect of pH on
Decolorization by Ozone
FIGURE 59. Dyeing Wastewater No. 12
(Direct Developed Dye on
Rayon): Effect of Ozone
Partial Pressure on De-
colorization
-------
of ozone significantly affected the degree of decoloriza-r
tion. The amount of ozone produced by the generator is
dependent upon the rate of gas flow through the unit, so
that at lower gas flow rates, a gas stream with a greater
partial pressure of ozone is produced by the generator.
Figure 59 shows that the ozone was more effectively utilized
in decolorizing the waste when it was present at a greater
volumetric percentage of the gas flow. With about 5% ozone
by volume, the waste was decolorized to less than 100 by
the application of 21 gms of ozone (approximately 3.5 mg/1).
A very small reduction in TOC was measured and the BOD in-
creased slightly for all samples. (It should be noted
that the color of the waste immediately prior to treatment
by ozonation was appreciably less than the initial color of
the fresh waste (2730 ADMI color units) pointing to in-
stability of the waste during storage. The ozone runs were
made following several weeks of storage.) Figure 85e shows
the appearance of one of the samples following ozonation.
Dyeing Wastewater No. 13. Disperse, Acid and Basic Dyes
on Polyamide Carpet - Exhaust
Coagulation of this combination wastewater with alum, at
doses up to 160 mg/1 as Al at pH 7, gave little reduction
in apparent color and only a small removal of TOC. Appli-
cation of lime at doses up to 4000 mg/1 (pH 12.2) resulted
in very little change in color.
Activated carbon adsorption proved to be an effective
method for treating the combined disperse/acid/basic dyeing
wastewater as illustrated in Figure 60. Five different
types of powdered carbon were investigated as shown in
Table 58, with Darco KB proving to be the most effective.
The Darco KB was tested at a dosage of 800 mg/1 at 5 dif-
ferent pH values as shown in Table 59, and pH 3 is seen to
be the most effective in both color and TOC removal. Fig-
ure 60 shows the effect of various dosages of the Darco KB
on the apparent ADMI color at two different pH values. It
is apparent that a carbon dosage, of 500 mg/1 at pH 3 was
sufficient to reduce the apparent color to 40. Similarly,
Figure 61 indicates that TOC removal by Darco KB was more
effective at pH 3, with 500 mg/1 reducing the TOC concen-
tration to 50 mg/1 and 1000 mg/1 reducing the TOC to 22
mg/1. Figures 85f and 85g show the apparent color of the
treated samples for the different types of PAC and for
Darco KB at pH 3,
Ozonation also proved to be an effective means of decolor-
izing the combination dyeing wastewater. Figure 62 shows
154
-------
700
200 400 600 800 1000
POWDERED ACTIVATED CARBON DOSAGE, mg/l
FIGURE 60, Dyeing Wastewater No, 13 (Disperse, Acid and
Basic Dyes on Polyamide Carpetl; Color Removal
by Powdered Activated Carbon Adsorption
155
-------
TABLE 58. EFFECT OF DIFFERENT TYPES OF POWDERED ACTIVATED
CARBONS ON TREATMENT OF DYEING WASTEWATER NO. 13 (DISPERSE/
ACID/BASIC DYES ON POLYAMIDE CARPET)
Type of
PAC
NUCHAR D-14
NUCHAR D-16
DARCO KB
DARCO HDB
DARCO HD-3000
Dosage,
mg/1
800
800
800
800
800
pH
6.5
6,5
6.6
6,7
6.6
TOCf
rag/1
56
53
42
66
60
Apparent
color
307
310
233
370
301
TABLE 59. EFFECT OF pH ON TREATMENT OF DYEING WASTEWATER
NO. 13 (DISPERSE/ACID/BASIC DYES ON POLYAMIDE CARPET) BY
POWDERED ACTIVATED CARBON
Dosage of
DARCO KB,
mg/1
800
800
800
800
800
pH
6,6
6.0
5.0
4,0
3.0
TOC,
mg/1
50
47
43
39
25
Apparent
color
193
236
207
139
53
156
-------
H
O
G
»
W
CTi
O i-3 ft) O
$j o 0) ^
h ft W fl>
D" 0) H- H-
O t-1 O 3
3 'Q
O 0
tQ (J) pj
fl) CO CO
3 ft
H- O CD
O 3 SI
0)
O t) ft
ft> O (D
TOTAL ORGANIC CARBON, mg/l
o ju a
330
H- ••
tr &
><: CD M
U)
T3 O
o j» '-
s; h o
fD fD W
fD •— ' (D
CL .. hj
CO
> Jd (D
O fl>-
ft 3
H- O >
-------
SSI
o
G
APPARENT ADMI COLOR VALUE
_ OJ ^ O>
W O O! O
o o o o
-------
that decolonization was not affected by pH with similar
decrees of decolonization achieved at pH 3.3 and pH 6,8.
Figure 63 shows the effect of the ozone partial pressure on
the efficiency of decolorization; increased partial pres-
sures of ozone, again generated by lower gas flow rates
through the generator, provided for more effective utili-
zation of ozone in decolorizing the waste. At a 5% ozone
concentration by volume, 8 gms of ozone (1.3 gm/1) was
sufficient to decolorize the waste to an apparent ADMI
color of 100, There was no reduction in total organic car-
bon but in all four samples tested, BOD increased as a re-
sult of ozonation.
In order to determine how efficiently ozone was utilized by
the wastewater in the given reactor configuration, the
ozonation run at neutral pH was repeated and the off-gas
collected and analyzed for its residual ozone concentration,
The off-gas was passed through a series of neutral buffered
KI absorbing solutions, over several different time periods
and the resulting 1^ was titrated with standardized thio-
sulfate. The data for the run are presented in Table 60
and the key features are illustrated in Figure 64. The
total absorption of ozone by the system over the 17-min run
was 67.1%. It is significant that, despite the small de-
gree of decolorization near the end of the run, a signifi-
cant amount of ozone (about 60% of that applied) was still
being absorbed by the waste. Although there was no removal
of TOC, even near the end of the run, it is possible that
some of the organic carbon was oxidized to a higher oxida-
tion state, but not to CO2. It is also plausible to expect
that a significant portion of the apparent ozone absorbed
simply decomposed to oxygen.
Dyeing Wastewater No. 14. Disperse Dye on Polyester - High
Temperature Exhaust
Lime dosages of up to 1000 mg/1 resulted in no apparent
loss in color and no measurable reduction in TOC. Figure
65 shows decolorization of the disperse dyeing wastewater
by coagulation with alum at two different pH values; pH 5
was again more effective than pH 7, but the color could not
be reduced to less than 200 by alum alone. Activated car-
bon, at dosages of up to 1000 mg/1 of Nuchar D-14 at pH 3,
proved to be relatively inefficient in removing color or
TOC as shown in Figure 66. Adsorption at pH 3 was more
effective than at pH 10.5, A two-stage treatment was at-
tempted combining coagulation by 65 mg/1 of aluminum at
pH 5 with treatment of the supernatant by Nuchar D-14, also
159
-------
TABLE 60. EFFICIENCY OF OZONE ABSORPTION DURING DECOLORIZA-
TION OF DYEING WASTEWATER NO, 13
Time,
min.
0
3
5
8
10
13
17
ADM I
color
value
666
347
276
190
150
131
100
Ozone
applied over
given time
interval ,
gms.
0
1.47
0.98
1.47
0.98
1.47
1.96
Cumulative
ozone
applied,
gms.
1.47
2.45
3.92
4.90
6.37
8.33
Ozone
collected in
exhaust
trap over
given time
interval ,
gms
0
0.18
0.35
0.39
0.40
0.60
0.82
Cumulative
ozone in
exhaust ,
gms.
0.18
0.53
0.92
1.32
1.92
2.74
Ozone
absorbed
over given
time interval,
gms.
-
1.29
0.63
1.08
0.58
0.87
1.14
Ozone
Cumulative absorbed
ozone
absorbed.
gms.
1.29
1.92
3.00
3.58
4.45
5.59
over given
time interval,
%
87.7
64.3
73.5
59.2
59.2
58.2
Average 67.1%
-------
8r- 800
V) c
£6
o»
Q
UJ
CO
(T
CD
UJ
O
CUMULATIVE OZONE
ABSORBED ASSUMING
100% ABSORPTION
EFFICIENCY
OZONE
LOST IN
OFF-GAS
ACTUAL
CUMULATIVE
OZONE ABSORBED
46
OZONE APPLIED,gms
FIGURE 64. Dyeing Wastewater No, 13 (Disperse, Acid and Basic Dyes
on Polyamide Carpet): Efficiency of Ozone Adsorption
and Utilization
-------
1200
200
ALUM ALONE, pH 7
ALUM ALONE,
pH 5
65 mg/l ALUM + PAC, pH 5
1
1
I
0
25
50 75 100 125
ALUM DOSAGE,mg/l as Al
I I I
150
0 400 800 1200
POWDERED ACTIVATED CARBON DOSAGE, mg/l
FIGURE 65. Dyeing Wastewater No, 14 (Disperse Dye on Poly-
ester) : Decolorization by Alum Coagulation Alone
and by Two-Stage Sequence Involving Alum Coagu-
lation and Powdered Activated Carbon Adsorption
162
-------
800
600 -
D
LU
oc
3400
8
5
o
200
NUCHAR D-l4,pH3
i
400
300
200
o>
O
CD
QL
<
O
o
K
O
O
100
0
FIGURE 66,
200 400 600 800 1000
POWDERED ACTIVATED CARBON DOSAGE, mg/I
Dyeing Wastewater No, 14 (Disperse -Dye on
Polyester): Color and Total Organic Carbon
Removal by Powdered Activated Carbon Alone
163
-------
at PH 5. Figure 65 shows that the powdered carbon had no
additional effect on the color of the waste, Five different
types of activated carbon were 'tested, but none were effec-
tive in reducing the color further, The nature of the resi-
dual color is not known, TOC was reduced approximately 65%
by alum, as shown in Figure 67, and removal was enhanced by
the subsequent addition of PAC, BOD5 was reduced by 50%,
to 96 mg/1, by coagulation with alum alone, at pH 5,
Ozone was moderately effective in decolorizing the disperse
dyeing wastewater as shown in Figure 68, The wastewater
contained an appreciable concentration of surfactant as
foaming was excessive when the 03/02 gas stream was diffused
into the column; a defoaming agent was required in order to
control the foam. The waste was readily decolorized by
20 gms of ozone (approximately 3.5 gms/1) to 400, but con-
tinued ozonation did not decolorize the waste further. Fig-
ure 85h shows the appearance of the ozonated samples. The
concentration of TOC was reduced only slightly.
Dyeing Wastewater No. 15, Sulfur Dye on Cotton - Continuous
Lime, alum and ferric iron all proved to be effective coagu-
lants of the sulfur dyeing wastewater as shown in Figure 69.
Again, alum was found to be more effective at pH 5 than at
pH 7 with doses of only 8 mg/1 as Al sufficient to reduce
the color to less than 100; 17 mg/1 of Fe(III) at pH 7 was
sufficient to reduce the color to 105, but Fe(IIl) should
be even more efficient at lower pH values (5-6). Five
hundred mg/1 of lime (pH 11,0) decolorized the sulfur dye-
ing wastewater to 100. It should be noted that the result-
ant floe from the additions of lime and alum did not settle
as well as the floe formed by ferric iron. The waste sample
was extremely foamy and a scum layer was formed on the sur-
face of all treated samples. Powdered carbon, at dosages
of up to 1000 mg/1 of Darco KB at pH 3.8, showed no apparent
color reduction. Despite the effective decolorization by
lime, alum and iron, little removal of TOC or BOD was
achieved. (A large part of the residual oxygen demand was
probably due to the presence of sulfides and polysulfides,)
Figure 85i shows the appearance of the samples after coagu-
lation by lime and alum.
Ozone was also relatively effective in decolorizing the sul-
fur dyeing wastewater but, again, due to the extremely high
surfactant content of the waste, a defoaming agent had to be
added. Figure 70 shows the effect of various dosages of
ozone on residual ADMI color at the initial pH of the raw
164
-------
300
o>
J-200
O
oo
tr.
<
o
o
CD
O
-------
(Ti
tT)
H
O
G
50
cn
02
O D
3 k<
(D
'•d H-
O 3
APPARENT ADMI COLOR VALUE
(D 'SI
W 03
rt tn
(D ft
'ft
D (D
0) 1-*
O
O &
M O
O •
J-S
p. I—I
N J^
0)
ft ^
H- D
O H-
3 CO
*O
tr o>
*< H
cn
O (D
N
O O
3 K<
(D (D
-------
400
300
LJ
5
or
3200
o
o
100
INITIAL
COLOR = 1450
\ Fe(HI), pH7
ALUM,
1
0
200 400 600
LIME DOSAGE, mg/l
I I
8OO
IOOO
u
0
1
10 20 30 40
ALUM DOSAGE, mg/l as Al
1 1 1
50
1 1
0
25 50 75
IRON (IE) DOS AGE, mg/l as Fe
100
FIGURE 69, Dyeing Wastewater No. 15 (Sulfur Dye on Cotton)
Color Removal by Lime, Alum, and Iron(III)
Coagulation
167
-------
1000
I
750
o
o
500
o
<
250
4.9% 03
7 Scfh
pH 3.6-3.0
I
I
10 20 30
OZONE APPLIED, gms
FIGURE 70. Dyeing Wastewater No, 15 (Sulfur Dye on
Cotton): Decolorization by Ozone
168
-------
waste. pH decreased slightly during the course of ozonation,
and 35 gins of ozone (approximately 6 gm/1) was required to
decolorize the sample to a value of 150, A parallel run was
also conducted at pH 5,8 and the data points coincide with
the plot in Figure70, suggesting that, in the acidic pH
range, there is no effect of pH on decolorization by ozone.
No reduction in TOC or BOD was found,
Dyeing Wastewa.ter No, 16, Reactive Dye on Cotton - Continu-
ous
Dosages of aluminum up to 160 mg/1 at pH 7 resulted in no
apparent reduction in color and only a 30% reduction in TOC.
Lime was also ineffective in removing color or TOC at doses
up to 1000 mg/1. In contrast, Figure 71 and Tables 61 and
62 show the effect of powdered carbon on the color of the
reactive dyeing wastewater. Six types of powdered carbon
were tested, with Darco HDB and KB being most effective
(see Table 61); decolorization was best at pH 6 (see Table
62). Figure 71 shows that a dosage of 1600 mg/1 of Darco
HDB at pH 6.0 was required to reduce the color of the re-
active dye to 100. TOC was also removed by PAC more effec-
tively at pH 6 than at pH 9, but the degree of removal was
only about 30% (see Figure 72). Figure 85j shows the appear-
ance of the samples after adsorption by Darco HDB at pH 6.
Ozone was very effective in decolorizing the reactive dyeing
wastewater as shown in Figure 73; decolorization was more
effective at the acidic pH value (pH 3.9) than at the
slightly alkaline pH value of the raw waste (pH 8.5) despite
the slightly lower partial pressure of ozone in the run at
pH 3.9. Under the acid conditions, the color was reduced
to less than 100 by the application of 7.5 gms of ozone
(1.25 gm/1). TOC and BOD were unchanged.
Dyeing Wastewater No. 17. Vat and Disperse Dyes on Polyes-
ter/Cotton - Continuous
Coagulation of the combination vat and disperse dyeing waste-
water by alum proved to be an effective means of treatment as
shown in Figure 74. Runs were made holding pH constant at
7 and 5 by the concurrent addition of acid or base along
with the alum, Decolorization, as before, was more effec-
tive at the lower pH, A third run with alum was made with
no concurrent pH adjustment and the residual color of these
samples are shown by the solid line in Figure 74, with the
pH values indicated in parentheses. The sample at 50 mg/1
of aluminum had a final pH of 6.0 and effected the same
169
-------
ADMI COLOR VALUE
-4
O
-------
TABLE 61. EFFECT OF DIFFERENT TYPES OF POWDERED ACTIVATED
CARBONS ON TREATMENT OF DYEING WASTEWATER NO. 16 (REACTIVE
DYE ON COTTON)
Type of
PAC
NUCHAR D-14
NUCHAR D-16
DARCO HDB
DARCO HD-3000
DARCO KB
HYDRODARCO C
Dosage,
mg/1
1000
1000
1000
1000
1000
1000
PH
8.6
8,4
9,1
9,1
8.9
9.0
TOC,
mg/1
180
188
111
183
168
187
ADMI
color
757
708
580
710
628
754
TABLE 62. EFFECT OF pH ON TREATMENT OF DYEING WASTEWATER
NO. 16 (REACTIVE DYE ON COTTON) BY POWDERED ACTIVATED CARBON
Dosage of
DARCO HDB,
mg/1
1000
1000
1000
1000
1000
1000
pH
9.1
8.0
7,0
6SQ
5,0
4.0
TOC,
mg/1
167
166
151
159
158
160
ADMI
color
609
481
418
257
305
300
171
-------
240
200
o>
E_I60
O
DO
on
<
o
o 120
o
(T
O
DARCO KB.pH 9
80
O
I-
40
0
DARCO HDB,pH 6
1
1
0 400 800 1200 1600 2000
POWDERED ACTIVATED CARBON DOSAGE,mg/l
FIGURE 72. Dyeing Wastewater No. 16 (Reactive Dye on
Cotton): Removal of Total Organic Carbon by
Powdered Activated Carbon
172
-------
400
UJ
3
§
300
a:
3
8200
o
<
100
INITIAL COLOR
5.0% 03
7 Scfh
pH 8.5-7.7
4.5% Og
7 Scfh v
"pH 3.9-3.6 \
1
1
0 5 10 15
OZONE APPLIED, gms
FIGURE 73. Dyeing Wastewater No. 16 (Reactive Dye on
Cotton): Decolorization by Ozone
173
-------
APPARENT ADMI COLOR VALUE
H
O
n o D
ft) (D
03 hg H-
d o 3
ft) !•<
rt CD 5!
H- cn ft)
O rt en
3 fD rt
I-! fD
\ C
O ft)
O rt
rt fD
rt ^
O
O M
O -J
M
o —
H D
H-
SO en
(D T3
3 (D
O H
< cn
ft) (D — "' —
cr
•<
ft)
ft"
rt
fD
tn
-------
degree of decoloriza,ti,on as the sample treated with alum and
adjusted to pH 5, Hence, due to the high initial alkalinity
of this particular waste, the addition of 50 mg/1 of alum
(an acid) brought the pH of the wa,ste into the proper range
for effective coagulation. The final apparent color value
at 50 mg/1 of AlCXIJ) was 80, as shown, TOC removal was
about 25%. Figure 85k shows the appearance of the samples
following coagulation by alum. (It should be mentioned that
although good removal of color was achieved, the supernatant
still foamed appreciably.)
Lime, at doses up to 1000 mg/1, produced no noticeable floe
and gave no apparent reduction in color. Powdered activated
carbon (Darco KB) was somewhat effective in decolorizing the
waste as shown in Figure 75, with color removal at pH 3.3
better than that at pH 11.0 but not as efficient as that
achieved by alum. The degree of TOC removal was small, as
shown.
Ozonation proved to be a relatively inefficient means of
decolorizing the combined vat/disperse dyeing wastewater.
Figure 76 shows that the apparent color could only be reduced
to 400 by the application of 50 gms of ozone (approximately
8.5 gm/1) at the alkaline pH value indicated; pH decreased
during the course of ozonation. A parallel run under acidic
conditions (pH 4.5 dropping to pH 3.2) resulted in a reduc-
tion in color to only 870 by the application of 15 gm of
ozone. TOC was reduced only slightly in both runs. (A de-
foaming agent had to be added to control the foam.)
Dyeing Wastewater No. 18. Basic Dyes on Polyester - Exhaust
Alum was ineffective in coagulating the basic dyeing waste-
water; although good floe were formed, no apparent color
reduction was noted at aluminum doses up to 160 mg/1 at pH
5. Lime doses up to 1000 mg/1 (pH 12.2) resulted in no floe
formation and little reduction in color. Activated carbon,
however, proved to be a very effective adsorbent of the
basic dyes. Table 63 shows that Nuchars D-14 and D-16 and
Darco KB were the most effective decolorizing carbons of
those tested, and Table 64 shows that decolorization was
best at pH 6-7. Figure 77 illustrates decolorization of the
waste by various doses of Darco KB at pH 5 (the pH of the
raw dyeing wastewater); 700 mg/1 of the carbon reduced the
color to 100, with increased carbon doses resulting in fur-
ther decolorization. A parallel run with Nuchar D-16 at
pH 5 gave the same degree of color removal as the Darco KB.
Additional runs with both Darco KB and Nuchar D-16 at pH 7
confirmed the data in Table 64 that, for this particular
175
-------
500
400
COLOR, pH 3.3
O
o
200
100
TOC,pH3.3 ^^
DARCO KB
I
I
500
400-
o>
300 I
<
o
o
200
100
0 500 1000
POWDERED ACTIVATED CARBON DOSAGE,mg/l
FIGURE 75. Dyeing Wastewater No. 17 (Disperse and Vat
Dyes on Polyester/Cotton): Color and Total
Organic Carbon Removal by Powdered Activated
Carbon
176
-------
CD
C
M
O O
3 k<
(D
h3 H-
O 3
APPARENT ADM I COLOR VALUE
(D S!
en P)
rt en
(D rt
i-« CD
\ C
n 0)
O rt
(D
rt
rt
O
t-S
2
O
D H
CD -J
O
O ~
H D
O H-
h en
N (D
Q) hj
rt en
H- CD
O O
N rt
O
3 O
CD •<:
(D
en
-------
TABLE 63. EFFECT OF DIFFERENT TYPES OF POWDERED ACTIVATED
CARBONS ON TREATMENT OF DYEING WASTEWATER NO. 18 (BASIC
DYES ON POLYESTER)
Type of Dosage,
PAC mg/1 pH
DARCO KB 40Q 5.0
DARCO HDB 400 5,3
DARCO HD-3000 400 4.9
HYDRODARCO C 400 5,2
NUCHAR D-14 400 5.0
NUCHAR D-16 400 5.0
TABLE 64. EFFECT OF pH ON TREATMENT
NO. 18 (BASIC DYES ON POLYESTER) BY
Dosage of
NUCHAR D-16,
mg/1 pH
400 3.0
400 4.0
400 5.0
400 6,0
400 7.0
TOC,
mg/1
700
970
780
860
860
850
OF DYEING
POWDERED
TOC,
mg/1
750
980
910
755
815
Apparent
color
262
1610
1630
1673
167
128
WASTEWATER
ACTIVATED CARBON
Apparent
color
249
172
163
110
104
178
-------
APPARENT ADMI COLOR VALUE
o (D a
si) m ^
t-i rt (D
cr CD H-
O M 3
a m
(D en
o rt
O (D
H SI
O C"
i^ rt
H- fl)
N n
0)
rt 2
H- O
o •
cr oo
•<:
TJ td
O 0)
s; en
PL H.
(D O
I-!
ro a
(D
> cn
n
rt O
CD h3
rt O
rt> M
i
[>
o
o
o
rn ro
xO O
m o
o
o
m
o
0
2) O
go
z
§£
l> O
§ 0
JT1
3
(0
^ O
O
o
_ ro 01 o O
3 Oi O O O O O
} O O O O O O
III 1
o /
/
/
/'
,'**
/
/ >
xX 8
/ 03
/
/ ^
/ 01
XX
/
- /o
/«
/
/
f
-------
waste, decolorization by carbon adsorption was more effective
under conditions of neutral pH than under the acidic pH con-
ditions of the raw waste.
TOC removal by PAC is shown in Figure 78. The initial TOC
of the raw waste was quite high (this wastewater had the
highest concentration of TOC and BOD of all twenty of the
dyeing wastewaters generated) and although the quantity (by
weight) of TOC removed by 1000 mg/1 of Darco KB at pH 5 was
appreciable, it only amounted to a TOC reduction of about
40%. The BOD concentration as a result of the carbon treat-
ment, however, was unchanged, It should be noted that the
treated samples still foamed upon handling. Figures 85£ and
85m show the effect of the different types of carbon on the
waste and the effect of various doses of Nuchar D-16 on the
appearance of the sample.
The basic dye was also readily decolorized by ozone but,
again, control of the foam was necessary. Decolorization
seemed to be more effective at lower pH values as shown in
Figure 79. Despite the relatively effective decolorization
to an apparent color of 300 with only 12 gms of ozone (2
gm/1), the color could not be reduced below 250. The nature
of the residual color and the reason for its resistance to
ozonation is unknown. There was no reduction in TOC by
ozone.
Dyeing Wastewater No. 19. Disperse, Acid and Basic Dyes on
Polyamide Carpet - Continuous~~
Figure 80 shows that only 8 mg/1 of Al(III) was sufficient
to decrease the color of this rather weakly-colored waste
to approximately 50. The TOC concentration remained the
same. No apparent color reduction was encountered, however,
when lime was applied even at doses up to 1000 mg/1.
When powdered carbon was tested for decolorization of the
combination dyeing wastewater, an appreciable loss in color
was observed when the treated samples were filtered through
the Reeve Angel filter paper used to separate the powdered
carbon from the solution (see Procedures, above). Even
filtration of the control, i.e., no PAC added, resulted in
an appreciable loss in color so that it was difficult to
determine whether, and to what extent, the observed decolor-
ization was due to the powdered carbon or to the filtration
step used for separation of the carbon. In order to deter-
mine if the sample could be decolorized by activated carbon
alone, a sample of crushed granular carbon was added to the
180
-------
1200
o 600
CD
cr
O
1
400
200
0
DARCO KB
1
1
200 400 600 800 1000
POWDERED ACTIVATED CARBON DOSAGE,mg/l
FIGURE 78, Dyeing Wastewater No, 18 (Basic Dyes on Poly-
ester) : Removal of Total Organic Carbon by
Powdered Activated Carbon Adsorption
181
-------
H
O
a
APPARENT ADMI COLOR VALUE
00
NJ
fD D
cn ><
rt CD
fD H-
I-! 3
s:
D OJ
fD cn
O rt
O fD
t- s:
O Q>
K rt
H- fD
N 1-1
P»
rt 3
H- O
O •
tr oo
^
o bo
N PJ
O cn
3 H-
fD O
a
*<:
fD
cn
o
13
-------
oo
OJ
IGURE 8
o
tr ro a
en fl>
> H- P-
H O 3
3 0^
"•< S!
n ro P)
O en en
(D rt
iQ O fl>
C 3 S
l_i PJ
P> TJ ri-
ff O fl>
H- M l-i
OK!
3 PJ 2
3 0
p- •
(D H1
vo
n
0) —
i~< D
*O p-
(D cn
— ft)
cn
O 0)
o -
1 — '
O !>
I-! 0
P-
n>
3 f
O 3
< a-
OJ
H
c
o
__
> o
r~
c
0
o
f\3
G^ V*C
jn O
3
(O
>^
^^
o
CO
> OJ
— o
^
O
ArrAKtlNl AUMI UULUK VALUE
Ol O CJI
3 O O O
1 1 1
1 1 1 ^
^^^
^nf
••**
^^^ ****
Or**
T ^y
\ J
1
1
1
t
1
__ i
1
1
Q
1
1
|
1
O
I
1
1
1
• I\D
0
O
_O
^-'r
^* i
-------
wastewater and mixed in the same fashion as the powdered
carbon but separation was achieved by simple sedimentation
of the coa,rser granular carbon (Darco HD-3000) . No reduction
in color was observed for the crushed granular carbon at
doses up to 1000 mg/1. It should be noted, however, that
only a, 6Q-mln contact period was provided for the crushed
granular carbon and such contact may have been insufficient
to achieve complete adsorption. Nevertheless, if activated
carbon were an effective decolorizing agent for this waste-
water, one would have expected at least partial adsorption
of the dye molecules, primarily at the exterior surface of
the carbon. No such decolorization was observed,
Decolorization of the mixed dyeing wastewater by ozone is
shown in Figure 81; 4 gms of ozone (about 670 mg/1) reduced
the color to less than 100. No defoaming agent was required,
Dyeing Wastewater No. 20. Azoic Dye on Cotton - Exhaust
The azoic dyeing wastewater contained an appreciable concen-
tration of highly-colored solids, with a suspended solids
concentration of 387 mg/1. The suspended particles tended
to settle quite readily on standing, however, so the physical-
chemical treatability studies were conducted on the colored
supernatant following sedimentation, (The ADMI color shown
in Table 5 in Section V (an ADMI color value of 2415) is the
soluble color after separation of the particles.) Alum and
lime were not required for coagulation of the solids as
they settled quite readily without the addition of chemicals.
The residual soluble color of the supernatant could not be
removed by Al(JII) doses up to 125 mg/1 at pH 7, or 800 mg/1
of lime (pH 12.1).
Powdered activated carbon, however, effectively decolorized
the residual supernatant as shown in Figure 82 and Table 65.
Darco HD-3000 and Nuchars D-14 and D-16 were the most effec-
tive decolorizing carbons (see Table 65). HD-3000 was
tested to determine the effect of pH on decolorization and
the results are depicted in the insert in Figure 82. There
appears to be a sharp break at about pH 6 to 7 and subsequent
treatment at pH 6 was tested at various levels of HD-3000
as shown; 800 mg/1 reduced the color to less than 100, TOC
removal was marginal as shown in Figure 83, A parallel run
with Nuchar D-16 at pH 6 gave comparable results to those
with the HD-3000. (No tests were performed in which the
powdered carbon was added prior to separation of the solids,)
184
-------
APPARENT ADMI COLOR VALUE
oo
U1
O
c
»
M
00
rt dd D
O en (D
3 H- P-
O 3
tr <&
t< a
j,j< ^ri
O (D JU
N cn cn
O rt
3 O (D
(D 3 S
0)
*x) r"i~
O CD
DJ S
3 O
H- •
fO H
n
ID
0
(D
>— (D
.. h{
Cfl
O (D
(D -
O
O >
H n
O H-
h CL
H-
-------
500 mg/l
HD-3000
I I
HD-3000 AT pH6
0 200 400 600 800 1000
POWDERED ACTIVATED CARBON DOSAGE, mg/l
FIGURE 82. Dyeing Wastewater No. 20 (Azoic Dye on Cotton):
Color Removal by Powdered Activated Carbon
Adsorption
186
-------
TOTAL ORGANIC CARBON, mg/l
oo
H
O
G
»
H
00
U)
£y 1/d O
O CD ><
rt 3 CD
H- O H-
< < 3
CD pj U3
ft H
CD 2!
Cb O P)
t-ti en
O rt
P) 1-3 CD
n o s;
tr ft pj
0 P) rt
3 M CD
H
O
H 2!
ua o
PJ •
3
H- to
o o
O —
hj N
tr o
o H-
3 o
cr a
ro
o o
C 3
CD O
!•< O
CD rt
fi rt
O
3
01
o
o
o
O
D .
3o
m o
o
^ oo
^ o
D
o
§8
O
o
ro
O
O
o
3J
O
o
o
o
p
•o
I
0>
b
-------
TABLE 65, EFFECT OF DIFFERENT TYPES OF POWDERED ACTIVATED
CARBONS ON TREATMENT OF DYEING WASTEWATER NO. 20 (AZOIC
DYES ON COTTON)
Type of
PAC
DARCO KB
DARCO HDB
DARCO HD-3QOO
HYDRODARCO C
NUCHAR D-14
NUCHAR D-16
Dosage,
. rag/1
1000
1000
1000
1000
1000
1000
PH
9.4
9,6
9.6
9.6
9.2
9.0
TOC,
mg/1
114
108
104
121
105
107
ADMI
color
499
645
335
1332
397
356
For the ozonation treatability study, the total azoic waste-
water, including the solids, was suspended in the reactor
and treated by ozone with the results shown in Figure 84.
Following an initially rapid decolorization of the sample
by 12 gms of ozone (2 gm/1) to an ADMI color value of 250,
the continued application of ozone was relatively ineffic-
ient in decolorizing the waste further. Although the waste
was eventually decolorized to less than 100, very large
quantities of ozone were required (approximately 10 gms/1).
SUMMARY
Table 66 summarizes the results of the physical-chemical
treatability studies for the twenty dyeing systems investi-
gated. The results are discussed along with the biological
treatability results in Section VIII.
188
-------
600
500
u
400
oc
g 300
o
o
200
100
\
INITIAL ADMI COLOR
2415
0
5.0% 03
7 Scfh
pH 9.1-7.3
15 30 45 60
OZONE APPLIED,gms
75
FIGURE 84, Dyeing Wastewater No, 20 (Azoic Dye on Cotton):
Decolorization by Ozone
189
-------
TABLE 66. SUMMARY OF PHYSICAL-CHEMICAL TREATABILITY STUDIES
Dyeing
Wastewater
No.
Dye Class
Vat
Substrate
Cotton
Color
1910
TOC,
rcg/1
Lime
1000 mg/1 reduced color to 350,
TOC to 210
1:2 Metal Complex Polyamide
370
400
1000 mg/1 reduced color to 230,
no reduction of TOC
Disperse
Polyester
300
no change in color or TOC up to
1000 mg/1
After-Copperable
Direct
Cotton
525
(1280a)
200 mg/1 reduced apparent ADMI
color to 120, little change in
TOC
Cotton
3890
150
no effect on color or TOC up to
3 gms/1
Disperse
Polyamide
Carpet
100
200 mg/1 reduced color to 50,
little removal of TOC
Acid/Chrome
Wool
3200
No color removal, some TOC removal
up to 2000 mg/1
Polyacrylic
5600
(12,000a)
255
2000 mg/1 ineffective for color
or TOC reduction
Prefiltration step omitted in ADMI color analysis.
-------
TABLE 66. SUMMARY OF PHYSICAL-CHEMICAL TREATABILITY STUDIES
(continued)
Dyeing
Wastewater
No.
Alum
140 mg/1 (pH 6.3) reduced
color to 100, TOC to 80
160 mg/1
-------
TABLE 66, SUMMARY OF PHYSICAL-CHEMICAL TREATABILITY STUDIES
(continued)
Dyeing
Wastewater
No.
Dye Class
Disperse
Substrate
Polyester
Carpet
Color
215
(315a)
TOC,
mg/1
Lime
1000 mg/1 reduced apparent color
to 130, TOC to 190
10
Acid
Polyamide
4000
1000 mg/1 reduced color to 2150,
no reduction of TOC
11
Rayon
12,500
140
3 gms/1 gave no appreciable
color or TOC removal
H
VO
to
Direct Developed
Rayon
2730
55
400 mg/1 reduced color to 300, TOC
to 30; higher doses gave no improve-
ment
Disperse, Acid,
Basic
Polyamide
Carpet
210
(720a)
no apparent color reduction up to
4 gms/1
Disperse
Polyester
360
1000 mg/1 gave no reduction in color
or TOC
15
1450
500 mg/1 reduced color to 100, no
effect on TOC, floe did not settle
well
Reactive
1390
1000 mg/1 gave no apparent color
reduction
aPrefiltration step omitted in ADMI color analysis.
-------
TABLE 66. SUMMARY OF PHYSICAL-CHEMICAL TREATABILITY STUDIES
(continued)
Dyeing
Wastewater
No.
u>
11
12
13
15
150 rag/1 (pH 5) reduced
apparent color to 80,
TOC to 110; very light
floe
160 rag/1 (pH 7) reduced
color to 2150, TOC to
160
30 mg/1 (pH 5) reduced
color to 2000, TOC to
30; color could not be
reduced by higher alum
doses
8 mg/1 (pH 5) reduced
color to 300, TOC to
30; no improvement at
higher doses
No apparent color re-
duction up to 160 mg/1
65 mg/1 (pH 5) reduced
color to 230, TOC to
130; no improvement at
higher doses
8 mg/1 reduced color to
less than 100, no effect
on TOC; floe settled
poorly
160 mg/1 (pH 7) gave no
apparent color reduction
2000 mg/1 Nuchar D-16
reduced TOC to 75 but
no change in color
1000 mg/1 Darco KB or
Nuchar D-14 reduced
color to 260, TOC to
175; pH 5.1 optimal;
cannot get color below
200 even at higher
doses
2 gms/1 gave no color
or TOC removal at pH
6.6
1000 mg/1 (pH 3.1)
gave no color reduc-
tion
^00 mg/1 Darco KB
(pH 3) reduced ap-
parent color to 40,
TOC to 50; acid pH
best
1000 mg/1 (pH 3) re-
duced color to only
500; little TOC re-
moval
1000 mg/1 (pH 3.9)
gave no apparent
color reduction
1700 mg/1 Hydro-
darco B (pH 6)
reduced color to
less than 50, TOC
to 140; pH 6 opti-
mal
Ozone
Decolorization rela-
tively slow; apparent
lag; acidification to
pH 4 more rapid than
at pH 7; apparent color
reduced to 70 by 4 gms/1
03; no change in TOC but
BOD increased with treat-
ment
Poor decolorization: color
reduced to 400 by 4 gms/1
03; pH dropped dramati-
cally (to 3.5) by ozona-
tion; no change in TOC but
BOD increased
Poor decolorization: 4.5
gms/1 03 reduced color to
1150; pH dropped during
treatment; small TOC re-
duction but BOD increased
Good color reduction: 3.5
gms/1 03 reduced color to
<100; no apparent pH
effect; small TOC reduc-
tion
Good decolorization: ap-
parent color reduced to
100 by 1.3 gms/1 03; no
effect of pH; no TOC re-
duction
Poor decolorization: 3.5
gms/1 03 reduced apparent
color to 400; defoamer
required; small reduction
in TOC
Color reduced to 150 by
6.0 gms/1 03; no apparent
pH effect; defoamer re-
quired; no change in TOC
Good decolorization:
color reduced to less than
100 with 1.2 gm/1 03; re-
action more efficient at
acidic pH; no change in
TOC
Other
Comments
High turbid-
ity wastewater,
some loss of
color using
ADMI procedure
with Celite
Two step treatment:
30 mg/1 alum at pH
5, 600 mg/1 Nuchar
D-14 reduced color
to 35, TOC to less
than 10
Two step treatment:
8 mg/1 alum at pH 5,
200 mg/1 Nuchar D-14
reduced color to 100,
TOC to 5
Two step treatment:
65 mg/1 alum at pH 5
+ Nuchar D-14 up to 2
gms/1 could not get
color below 200
17 mg/1 Fe(III) re-
duced color to 100
at pH 7 with good-
settling floe
Sample extreme-
ly foamy, scum
layer formed
on all treated
samples
-------
TABLE 66. SUMMARY OF PHYSICAL-CHEMICAL TREATABILITY STUDIES
(continued)
Dyeing
Wastewater
No.
17
Dye Class
Vat, Disperse
Substrate
Polyester/
Cotton
Color
365
(1100s
TOC,
mg/1
350
Lime
no floe formation or color removal
up to 1000 mg/1
18
Basic
Polyester
1300
(2040a)
1120
no apparent color reduction up to
1000 mg/1
19
Disperse, Acid,
Basic
Polyamide
Carpet
<50.
(190°
160
no apparent color reduction up to
1000 mg/1
20
Azoic
Cotton
2415
170
800 mg/1 had no effect on super-
natant color
Prefiltration step omitted in ADMI color analysis.
-------
TABLE 66. SUMMARY OF PHYSICAL-CHEMICAL TREATABILITY STUDIES
(continued)
Dyeing
Wastewater
No.
17
18
Ul
19
20
Alum
50 mg/1 reduced apparent
color to 80, small TOC
removal; no adjustment
of pH required; treated
sample still foamed
No apparent color reduc-
tion up to 160 mg/1 at
pH 5
8 mg/1 (pH 7) reduced
color to 50; no change
in TOC
125 mg/1 had no effect
on supernatant color
PAC
1000 mg/1 Darco KB at
pH 3.3 reduced apparent
color to 325
700 mg/1 Darco KB
(pH 5) reduced apparent
color to 100,' TOC re-
duced to 700; pH 6-7
optimal
no apparent decolori-
zation
800 mg/1 of Darco HD-
3000 or Nuchar D-16
at pH 6 reduced color
of supernatant to 100;
TOC removal slight;
acid "pH best
Ozone
Poor decolorization: 9
gms/1 03 reduced ap-
parent color to 400;
defoamer required;
slight TOC reduction
Apparent color reduced
to 300 by 2 gms/1 03
but could not be re-
duced below 250; de-
foamer required; acidic
pH better than neutral
pH; no reduction in TOC
Good decolorization to
less than 100 by 500 mg/1
03; TOC reduced slightly
Efficient initial decolor-
ization to 260 by 1.5 gms/1
03 followed by slower de-
colorization to less
than 100 by 11 gms/1 03;
defoamer required; no
change in TOC
Other
Comments
Appreciable
loss in color
by Celite
filtration
Some color
lost via
Celite filt-
ration, treat-
ed sample
still foamed
Very slight
color; color
removed easily
at all inter-
faces, e.g. ,
filters, Ce-
lite, Al (OH) 3
Waste contain-
ed appreciable
suspended
solids concen-
tration with
color associ-
ated with
particles;
solids (and
associated
color) settled
readily on
standing
-------
f^/A^I^' ° .-^ S;1^-?^ ^ ^^ ^%
t '- f ,ri ', * , _,- ' "* * 4 i-
1 f~-%' '^ \ t 1 *u -.'->/•' " ' '
^it^kM^:'^l•"•' "5" ' • t "^^ •. :, ;" "• " ,~"'c' , ' ,
,••»* <""- -
t. _> °=liiXl
'^S*"L." -e ' "',' "' =--
rl u^ " 1 ^ l ' ^^
P'^' , -'} *v:V"'%, "!'*;::^
kf- - r^:-, f~ ',-->; , :!.
1 r-v'- ^'u ;,f
-I £?*r i!t ,- .' - t \
•
A jt ~ t -1 ^ v& J
t -^M^s'^^
-•;:a!l^:f^v|i
1 f sfrsZg'^ ^' ^°"-r, ^
FIGURE 85, Colored Photograph Showing Effect of Different
Treatments on the Appearance of Representative
Dyeing Wastewater
196
-------
TABLE 67, LEGEND FOR FIGURE 85
a. Decolorization of Dyeing Wastewater No. 10 (Acid Dye on Polyamide) by Powdered
Activated Carbon (Darco HD-3000 at pH 5.1)
Carbon 0 200 400 600 800 1000 1200 1400 2000 4000 Pt-Co Pt-Co
Dosage, Stan- Stan-
mg/1 dard dard
ADMI
Color
Value 4116 3140 2155 1828 832 289 289 251 210 228 50 300
b. Decolorization of Dyeing Wastewater No. 10 (Acid Dye on Polyamide) by Ozone
Ozone 0 5.0 7.3 12.3 17.8 22.8 Pt-Co Pt-Co
Applied, Standard Standard
gms
pH 6.6 5,2 4.8 4,2 3.8 3.5
ADMI
Color
value 1790 815 680 560 480 420 50 300
-------
TABLE 67, LEGEND FOR FIGURE 85 (continued)
c. Decolorization of Dyeing Wastewater No. 11 (Direct Dye on Rayon) by Alum Coagu-
lation Alone (at pH 5) and by Two-Stage Treatment Consisting of Alum Coagulation
(at pH 5) followed by Powdered Activated Carbon (Nuchar D-14)
Type of Raw Alum Alum Alum 32 32 32 32 Pt-Co Pt-Co
Treat- Dye Only Only Only mg/1 mg/1 mg/1 mg/1 Stan- Stan-
ment Waste 16 32 161 Alum, Alum, Alum, Alum, dar'.d dard
pH mg/1 mg/1 mg/1 400 500 600 800
6.6 mg/1 mg/1 mg/1 mg/1
PAC PAC PAC PAC
£ ADMI
Color
Value 12,500 7920 1975 1937 187 97 35 36 50 300
d. Decolorization of Dyeing Wastewater No, 11 (Direct Dye on Rayon) by Ozone
Ozone 0 9,3 18.6 28.0 Pt-Co Pt-Co
Applied Stan- Stan-
gms dard dard
pH 9.5 4,3 3.6 3.4
ADMI
Color Value 12,230 5550 3790 1145 50 300
-------
TABLE 67, LEGEND FOR FIGURE 85 (continued)
e. Decolorization of Dyeing Wastewater No. 12 (Direct Developed Dye on Rayon)
by Ozone
Ozone 0 7,3 10.7 14.6 25,4 36,1 Pt-Co Pt-Co
Applied Stan- Stan-
gms dard dard
PH 2,8 2,7 2,7 2,7 2,6 2.6
ADM I
Color „ ^
Value 1725 1800 1380 635 210 210 50 300
f. Decolorization of Dyeing Wastewater No, 13 (Disperse, Acid, and Basic Dyes
on Polyamide Carpet) by Different Types of Powdered Activated Carbons (800
mg/1 at pH 6,6)
Type of Nuchar Nuchar Darco Darco Darco Pt-Co Pt-Co
pAC D-14 D-16 HDB HD KB Stan- Stan-
3000 dard dard
Apparent
ADMI 300 311 371 302 234 50 300
Color
Value
-------
O
O
TABLE 67. LEGEND FOR FIGURE 85 (continued)
g. Decolorization of Dyeing Wastewater No, 13 (Disperse, Acid, and Basic Dyes
on Polyamide Carpet) by Powdered Activated Carbon (Darco KB at pH 3.0)
Carbon 0 0 200 300 400 500 600 700 800 900 Pt-Co Pt-Co
Dosage pH pH Stan- Stan-
mg/1 3.0 6,6 dard dard
Apparent
ADMI 830 750 306 175 97 38 32 22 32 25 50 300
Color
Value
h. Decolorization of Dyeing Wastewater No, 14 (Disperse Dye on Polyester) by
Ozone
Ozone 0 4,6 7,2 13,5 21.9 Pt-Co Pt-Co
Applied, stan- stan-
gms dard dard
pH 9,7 6.7 6.6 6.2 6.1 —
ADMI
Color
Value 1180 377 366 325 280 50 300
-------
TABLE 67. LEGEND FOR FIGURE 85 (continued)
i. Decolorization of Dyeing Wastewater No. 15 (Sulfur Dye on Cotton) by Coagu-
lation
Type of Raw Dye 400 mg/1 800 mg/1 17 mg/1 Pt-Co Pt-Co
Treatment Waste Lime Lime Alum, Standard Standard
pH 5
ADMI Color
Value 1450 122 48 63 50 300
j. Decolorization of Dyeing Wastewater No. 16 (Reactive Dye on Cotton) by
w Powdered Activated Carbon (Darco HDB at pH 6,0)
o
Carbon 0 500 1000 1300 1500 1600 1700 Pt-Co Pt-Co
Dosage, Stan- Stan-
mg/1 dard dard
ADMI Color
Value 1400 705 341 203 106 83 42 50 300
-------
TABLE 67, LEGEND FOR FIGURE 85 (continued)
k. Decolorization of Dyeing Wastewater No, 17 (Disperse and Vat Dyes on Polyester/
Cotton) by Alum Coagulation
Alum Dosage 0 32 40 48 55 Pt-Co Pt-Co
Standard Standard
pH 10.9 7.5 6.6 6,1 5,6 — ---
Apparent
ADMI Color 1189 1059 239 71 58 50 300
Value
1. Decolorization of Dyeing Wastewater No, 18 (Basic Dyes on Polyester) by Differ-
ent Types of Powdered Activated Carbons (400 mg/1 at pH 5,0)
Type of Raw Darco Darco Darco Hydro Nuchar Nuchar Pt-Co Pt-Co
PAC Dye KB HDB HD Darco D-14 D-16 Standard Standard
Waste 3000 C
Apparent
ADMI 1400 263 1611 1631 1674 168 129 50 300
Color
Value
-------
TABLE 67. LEGEND FOR FIGURE 85 (continued)
m. Decolorization of Dyeing Wastewater No, 18 (Basic Dyes on Polyester) by
Powdered Activated Carbon (Nuchar D-16 at pH 5,0)
Carbon 0 100 200 300 400 500 Pt-Co Pt-Co
Dosage, Standard Standard
mg/1
ADMI
Color _rt^
Value 1282 922 395 88 58 63 50 300
O
U>
-------
SECTION VIII
DISCUSSION OF TREATABILITY RESULTS
BIOLOGICAL TREATABILITY
Objectives of this research were to compare the biological
treatability of the twenty dyeing wastewaters and to deter-
mine the effect on nitrification. These studies were per-
formed at laboratory scale, using procedures similar to those
employed for determining long term BOD; the wastewaters
tested were generated in well-defined standard dyeing opera-
tions. These results, therefore, are intended only as a guide
in biological treatability of dyeing wastewaters, and further
experimentation will be required to generate the information
for design of plant-scale wastewater treatment systems.
Tables 68 and 69 summarize results from laboratory-scale
studies of biological treatability of the dyeing wastewaters.
The results show that at the 10% strength, > 90% of the solu-
ble BOD5 was removed in 18 of the 20 cases, and at full
strength, > 90% removals were achieved in 15 of the 20 cases.
Only in one case, no. 5, were BOD removals less than 50%.
Dyeing wastewater no. 5 inhibited biological activity at the
10% and 100% strengths. It was also not possible to main-
tain a bench-scale activated sludge system when this waste-
water was present in the feed. Results from the lowest
strength (1%) are hard to interpret since it was not possible
to perform BOD's. The initial TOC levels were low at this
strength; however, removal of most of the TOC possibly indi-
cates that some biological treatment occurred. Dyeing waste-
water no. 5 contained an unusually high level of chlorides
(9800 mg/1) and more chloride was added when the pH was
lowered with HC1 from 11.2 to 7 for the biological treatabil-
ity studies. Due to other sodium salt components in the dye-
bath, it is conceivable that sodium inhibition might be in-
volved. Since inhibitory effects were noted at the 10%
strength, at which the chloride and other dissolved solids
were diluted by tenfold, it would seem doubtful that the
dissolved solids concentration was responsible for the inhi-
bition. Many common bacteriological media contain 5 g of
NaCl per liter, and some industrial wastewater treatment
systems are known to operate successfully at chloride levels
of -17,000 mg/1.
In the case of wastewater no. 5, the dyeing process also
involved addition of an anti-reducing agent, sodium m-nitro-
204
-------
TABLE 68. EFFECT OF BIOLOGICAL TREATMENT ON BOD, TOC, AND
COLOR REMOVAL FROM DYEING WASTEWATERS
A. BOD5 REMOVAL
B. TOTAL ORGANIC CARBON REMOVAL
M
O
Ui
Removal , %
DILUTION
10%
100%
<50
5
5
50-89
17
8, 13,
17, 18
>90
1, 2, 3, 4,
6, 7, 8, 9,
10, 11, 12,
13, 14, 15,
16, 18, 19,
20
1, 2, 3, 4,
6, 7, 9, 10,
11, 12, 14,
15, 16, 19,
20
Removal , %
<50
3, 5,
10, 11,
12, 14
50-89
1, 2, 3, 4,
5, 6, 7, 8,
9, 10, 11,
13, 14, 16,
17, 20
1, 2, 4, 6,
7, 8, 9, 13,
16, 17, 18,
19, 20
;>90
12, 15, 18,
19
15
C. COLOR REMOVAL3
Removal, %
<50
3, 4, 5,
6, 7, 10,
11, 12,
14, 16,
17, 18,
20
1, 2, 3,
4, 5, 6,
7, 8, 9,
10, 11,
12, 16,
17, 18
50-89
1, 2, 8,
13, 15
13, 15,
20
290
No. 7 was not measured at the 100% level; the color at 10% strength was too low for analysis in the case of
No. 9, and for No. 19 the color was too low at both the 10% and the 100% strengths.
-------
TABLE 69, EFFECT OF DYEING WASTEWATERS ON NITRIFICATION
Set
Inhibition3'b
None
A-10
B-10
1,2,5,6,7,9,
11,12,13,15,
16,17,18,19
2,6,9,11,13,
15,16,17,18,
19
Moderate
3,14
Marked
4,8,10
1,3,4,5,7,8,
10,14
A-100
B-10
6,11
6,16
16
9,11,13
1,3,4,5,7,8,
9,10,13,14,
15,17,18,19
1,3,4,5,7,8,
10,14,15,17,
18,19
aNone -- >50% of initial TKN as N02+N03~N (final)
Moderate — 20-49% of initial TKN as N02+NO3-N (final)
Marked — <20% of initial TKN as NO +N03~N (final)
bNo data for no. 2 at 100%; for no. 12 at B-10 and at 100%;
no data for no. 20.
benzene sulfonate, but this agent was also employed in dyeing
wastewater no. 16, a wastewater which was readily treatable.
The reactive red dye used in dyeing wastewater no. 5 is there-
fore suspect. Further studies with the dye alone might reveal
whether or not it inhibits exertion of BOD.
Overall, it is reasonable to conclude that in 19 of 20 cases,
presence of dyes in dyeing wastewaters did not interfere with
the removal of BOD.
TOC was generally removed to a lesser degree than the BOD
(Table 68). In the majority of cases, 50-89% removals were
achieved in seeded flasks. In Table 70 BOD^/TOC ratios are
shown before and after treatment.
The BODc/TOC ratios in
206
-------
domestic wastewaters are generally ~1.62 in the raw waste,
~0.47 in the effluent,1 It should be noted that the BOD
test is a test of biochemical oxygen consumption and that
the test may not reflect the presence of organic compounds
which are partially or totally resistant to biodegradation.
On the other hand, the TOG test recovers all the organic
carbon, regardless of its biodegradability. Since biological
treatment removes biodegradable organics, refractory organic
carbon will account for a larger portion of the TOC in the
effluent than in the raw wastewater. Thus, the BODr/TOC
ratio will be lower in the effluent. Table 70 readily illus-
trates the lowering of the ratio by treatment. In the raw
wastewaters the ratios are, with only 4 exceptions, lower
than that characteristic of domestic sewage.
In the treated wastewaters the ratios were generally lower
than for treated domestic wastewaters and in many cases were
0.0, indicating that the refractory component accounted for
nearly all of the remaining TOC,
Because of the lack of precision of the BOD test and because
of the very low residual BOD5 levels in many cases, the in-
formation in Table 68 must be interpreted cautiously. How-
ever, it is apparent that the majority of the wastewaters
contain organics which are only partially degraded even after
21-day culture with acclimated organisms. This possibly
indicates that these organics would not be oxidized in bio-
logical wastewater treatment systems.
Under the conditions tested, biological treatment appears to
be inadequate for color removal. The raw wastewater color
levels were low in dyeing wastewater no. 19, In the remain-
ing 19 cases, color removals of less than 90% were achieved,
and in the large majority of cases, less than 50% removal
was achieved (Table 68). In some cases, soluble color in-
creased during treatment.
The effect of dyeing wastewaters on nitrification (Table 69)
warrants further investigation, In a previous study,2 sev-
eral dyes were shown to interfere with nitrification in dye-
supplemented domestic wastewater. For many years, the dye
methylene blue has been known to inhibit nitrification.3'4
In the degradation of organic nitrogen compounds, ammonia is
usually produced by microbiological processes referred to as
"ammonification," Nitrification, a microbiological process,
involves the oxidation of the ammonia nitrogen to nitrite
and subsequently to nitrate. Because of the toxicity of
ammonia to fish and because of the nitrogenous oxygen demand
which would be exerted if ammonia were discharged to a sur-
207
-------
TABLE 70. EFFECT OF BIOLOGICAL TREATMENT ON BOD5/TOC RATIOS
IN DYEING WASTEWATERS WITH ACCLIMATED SEED
Dyeing
Wastewater Set
1 B-l
B-10
B-100
2 B-l
B-10
B-100
3 B-l
B-10
B-100
4 B-l
B-10
B-100
5 B-l
B-10
B-100
6 B-l
B-10
B-100
7 B-l
B-10
B-100
8 B-l
B-10
B-100
9 B-l
B-10
B-100
10 B-l
B-10
B-l 00
208
BOD5/TOC
Initial
1.4
1.1
0.9
0.8
0.6
1.2
1.7
1.4
1.0
1.2
1.0
0.8
1.4
1.2
0.7
0.8
1.0
0.9
1.0
1.4
0.8
1.0
0.7
1.2
1.0
0.7
Final
<0.1
0.0
0.3
0.03
0.5
0.1
0.0
0.7
0.2
0.5
<0.1
0.0
0.2
0.0
0.2
0.4
0.7
<0.1
0.0
0.5
<0.1
0.0
-------
TABLE 70. EFFECT OF BIOLOGICAL TREATMENT ON BOD5/TOC RATIOS
IN DYEING WASTEWATERS WITH ACCLIMATED SEED (continued)
BOD5/TOC
Dyeing
Wastewater
11
12
13
14
15
16
17
18
19
20
Set
B-l
B-10
B-100
B-l
B-10
B-100
B-l
B-10
B-100_
B-l
B-10
B-100
B-l
B-10
B-100
B-l
B-10
B-100
B-l
B-10
B-100
B-l
B-10
B-100
B-l
B-10
B-100
B-l
B-10
B-100
Initial
1.7
1.1
0.3
1.2
1.2
0.6
1.2
1.1
0.8
1.0
0.7
0.4
0.8
1.7
2.0
1.0
1.0
1.0
1.4
1.4
1.7
1.4
1.0
1.1
1.0
0.8
0.9
1.2
Final
<1.0
<0.1
0.0
0.3
0.0
<0.5
0.8
0.3
0.1
0.0
0.1
1.4
<1.0
<0.0
<1.0
<0.2
0.1
1.7
<0.5
0.4
<0.2
<0.1
0.8
<1.0
0.0
<0.5
0.5
0.0
209
-------
face water, there is currently interest in setting effluent
standards which require low levels of ammonia nitrogen. One
of the processes for removing ammonia is biological nitri-
fication, which can be achieved in extended aeration systems,
or in specially designed activated sludge or trickling filter
systems. In the presence of certain of the dyeing waste-
waters tested little or no conversion of total Kjeldahl nitro-
gen (organic + ammonia nitrogen) to nitrate was achieved.
Little or no nitrate formation was observed with wastewaters
nos. 3, 4, 8, 10, and 14 at 10% strength; at full-strength,
little or no nitrate formation occurred with nos. 1, 5, 7,
15, and 17. The data for no. 19 were difficult to interpret,
but no increase in nitrate occurred. No data on the final
concentrations of nitrogen forms was available for no. 20.
These observations indicate that either ammonification and/or
nitrification failed to occur.
Computation of nitrogen balances, even for domestic waste-
water, is difficult and often up to 20% of the nitrogen can-
not be accounted for. The interference of the dyes with
spectrophotometric analyses, even with standard addition
techniques, also complicated interpretation of the final re-
sults. However, it seems reasonable to conclude that some
component of a number of the wastewaters either interfered
with nitrification or was resistant to ammonification. Stud-
ies of the effects of specific dyes on nitrification of
domestic wastewater and of stream water are in progress.
PHYSICAL-CHEMICAL TREATABILITY
The purpose of this section is to compare the twenty dyeing
wastewaters as to their treatability by physical-chemical
techniques. The major emphasis is on decolorization while
TOG removal is considered to be of secondary importance;
TOC was removed quite readily by biological oxidative pro-
cesses whereas color was difficult to remove by such pro-
cesses, as demonstrated by the biological treatability re-
sults discussed above and by numerous textile plant experi-
ences. Again, the reader is cautioned that the results were
derived from a laboratory-scale, batch treatability analysis
and are intended to serve only as a guide in selecting the
most appropriate treatment method and chemical conditions
for the full-scale treatment of real textile wastewaters.
Adsorption and Coagulation
Table 71 presents a summary of the adsorption and coagulation
results showing the best means of decolorization for each of
the twenty dyeing wastewaters sub-divided by dye class.
210
-------
TABLE 71. COAGULATION AND ADSORPTION: BEST MEANS OF DECOLOR-
IZATION BY DYE CLASS
Dveinq
Dye class
Wa-f-
V Ct l~
Disperse
Disperse
Disperse
Disperse
Vat + disperse
Sulfur
Reactive
Reactive
Basic
Basic
Acid
Azoic
1:2 metal complex
Direct
(after-
copperable)
Direct
Direct developed
Disperse + acid
+ basic
Disperse + aci(d
+ basic
Acid/chrome
no.
1
3
6
9
14
17
15
5
16
8
18
10
20
2
4
11
12
13
19
7
Substrate
Cotton
Polyester
PQlyamide
carpet
Polyester
carpet
Polyester
Polyester/
cot ton
Cotton
Cotton
Cotton
Polyacrylic
Polyester
Polyamide
Cotton
Polyamide
Cotton
Rayon
Rayon
Polyamide
carpet
Polyamide
carpet
Wool
ADMI
color Best
value treatment
1910 Alum coagulation
315 Alum coagulation
100 Alum coagulation
315a Alum coagulation
1245 Alum coagulation
1100a Alum coagulation
1450 Alum coagulation
3890 Carbon adsorption
1390 Carbon adsorption
12.000a Carbon adsorption
2040a Carbon adsorption
4000 Carbon adsorption
2415 Carbon adsorption
370 Carbon adsorption
1280a Alum
12,500 Alum + Carbon
2730 Alum + Carbon
720a Carbon adsorption
190a Alum
3200 Fe(II)
aPrefiltration step omitted prior to ADMI color analysis.
211
-------
(Treata.bility by chemical oxidation with ozone is considered
in the next section.) The vat and disperse dyeing 'waste-"
waters and the one sulfur dyeing wastewater were decolorized
most effectively by coagulation with aluminum and quite
ineffectively, in general, by activated carbon adsorption
Ferric iron or other coagulants and flocculants (such as
b^hT ??lyteS) C°Uld Probably ^ u8ed in place of alum,
have So effectiveness of these alternative chemicals would
have to be evaluated, in the case of Fe(III), some care must
be exercised since underdosing the system with insufficient
Fe(III) can result in a marked enhancement of the color due
to the presence of the yellowish-brown colloidal ferric hvdrox-
ide as was observed for dyeing wastewater no. 3. Sme can
also be used as a coagulant, but its effectiveness is limited
to systems where there is an appreciable carbonate alkalinity
to allow formation of CaC03 . Lime was found to-be effective
dye? Candr4Z^fVWaSteS * ^ 9 (disPerse dyes) , 15 (sulfur
dye) and 4 (af ter-copperable direct dye), and partially
6 °;SteS X (Vat dye)' 2 (1:2 metal complex dye),
-developed) ; it was ineffective in decolorizing
Decolorized by*
Pr°ved t0 be an effective means
the reactive, basic, acid, azoic, and 1-2
wastewaters. Correspondingly, coagula-
6 *" en *n dec^lor-
statements c^n be made about the other dyeing
re o d 1?Vestl^ted as the^ consisted of either a mix-
ture of dye classes (e.g., wastes 13 and 19) or required a
SSn^e a" £f ^^T^' , ^' ' b°th coaguiation^nd adsSrp-
tion (e.g., wastes 11 and 12). The af ter-copperable direct
dyeing wastewater (no. 4) was decolorized mos? eJfectivefy
a^on?9? S °?HWlth llme °r alUm SlnCe most of the color was
associated with suspended particles which could be readily
destabilized and aggregated by the coagulants. Dyeing waste-
Ized'mSst L?°^ainf Sn aCld dye and ?r(VI) and ^s decSlo?-
ized most effectively by reduction of the highly-colored
Son wiS Mme!r°US "^ ^ l™ P* ^ subse^e-t neutraliza-
Table 72 shows the best treatment in terms of requisite alum
remov^? ^ COrresP°ndi^ d^ree of decolorizSion anf TOC
removal for those wastes which were most treatable by coaou-
lation. The "best" treatment was selected as that dosage^of
alum beyond which the decolorization curve (i.e., plot of
residual color vs alum dosage) levels off (see Section VII)
-------
TABLE 72. REQUISITE ALUM DOSAGES FOR BEST DEGREE OF
DECOLORIZATION, AND CORRESPONDING REMOVALS
OF TOTAL ORGANIC CARBON
NJ
Dyeing
Dye class no.
Disperse 3
Disperse 6
Disperse 9
Disperse 14
Vat 1
Vat/Disperse 17
Sulfur 15
Disperse/Acid/ 19
Basic
After-copper able
direct 4
Requisite
alum
dosage,
Substrate mg/1 as Al
Polyester 60
Polyamide 30
carpet
Polyester 160
carpet
Polyester 60
Cotton 80
Polyester/ 50
cotton
Cotton 8
Polyamide 8
Cotton 15
Initial
color
value
315
100
315a
1245
1910
1100a
1450
190a
1280a
Final
color
value
45
50
80a
230
140
80S
80
55a
80a
Initial
TOC,
mg/1
300
130
240
360b
265b
350
400
160
135
Final
TOC,
mg/1
170
110
115
130
115
300
345
135
100
TOC
Reduc-
tion,
43
15
52
63
56
14
13
15
25
.3
.4
.1
.9
.6
.3
.8
.6
.9
aPrefiltration step omitted.
blnitial TOC for coagulation study appreciably less than TOC of raw fresh waste,
-------
The TOG removals shown correspond to these same alum dosages.
In all cases, alum was most effective in the pH range 5 to 6;
pH control is mandatory for efficient coagulation by A1(IIJ)1
The required doses vary for the different wastes over the
range 8 .to 160 mg/1 as Al, and it is apparent that the requi-
site dosage is not correlated to the initial color value but
depends more significantly upon the type of dye and the other
components of the dyeing wastewater. The requisite alum dos-
age to achieve effective decolorization depends upon whether
the dye bodies are suspended or dispersed as colloidal parti-
cles or whether they are present as dissolved species; if
dissolved, the effectiveness of alum in removing them depends
upon their affinity for the aluminum hydroxide surface compared
to other dissolved components in the waste, e.g., phosphate,
which compete for the adsorptive sites on the surface. For
example, both dyeing wastewaters 3 and 9 were generated by
dyeing polyester fabric with Disperse Yellow 42 and Disperse
Blue 87 and both had the same initial color value of 315.
Waste no. 3 resulted from dyeing a polyester texturized double
knit while no. 9 resulted from the dyeing of a polyester
tufted carpet; both dyeings were performed by atmospheric
exhaust on the same dye beck and at the same liquor ratio
(30:1). Many of the components of both dye baths were the
same (e.g., complex diaryl sulfonate dispersing agents,
ethylene oxide non-ionic detergents, polyphosphates, acetic
acid, and sodium hydrosulfite) albeit in different amounts,
but dyeing system no. 3 contained orthophenyl phenol as the
carrier while dyeing system no. 9 contained biphenyl as the
carrier. Comparison of the raw waste characteristics (see
Section V) shows that waste no. 9 had a higher suspended
solids concentration than waste no. 3 (101 mg/1 versus 39
mg/1, respectively); the TOG of the wastes were similar (300
mg/1 and 240 mg/1 for wastes 9 and 3, respectively). Ortho-
phenyl phenol is appreciably more soluble than biphenyl and
it would appear that the difference in the suspended solids
concentrations and therefore the different requisite chemical
doses for these two wastes is attributable to the different
carriers used in the dye bath. It is interesting to note
also that waste no, 14, generated by the disperse dyeing of
polyester yarn by the high<-temperature exhaust method using
trichlorbenzene as the carrier, resulted in a waste that was
difficult to decolorize to the same extent as the other
disperse-on-polyester dyeings. As shown in Figure 65,
increased applications of alum were unable to decolorize the
sample below 200 ADMI color units. The significance of the
other components of the dye bath and the differences in the
chemical properties of the dye molecules themselves cannot
be underestimated with respect to their effect on the requi-
site coagulant dosages and the resulting degrees of decolor-
ization.
214
-------
A similar statement can be made regarding TOC removal as it
is apparent from Ta.ble 72 that the percent removals of TOC
are quite different for the different dyeing wastewaters,
even for wastewaters generated by dyeings from the same class
of dyes. It can be concluded, in general, that alum coagula-
tion is not very effective in removing total organic carbon
from the wa,stewaters investigated, percent reductions ranging
from 13 to 64%.
Table 73 summarizes the, requisite activated carbon doses for
decolorizing those wastes which were most treatable by ad-
sorption. Again, the "best" treatment was selected as that
dosage of PAC beyond which the decolorization curve leveled
off. Also indicated are the most effective types of carbon
among those investigated for each of the wastes, and the
optimum pH conditions for decolorization. The corresponding
TOC removals are also shown. Again, as in the case of alum,
it is apparent that there is no correlation between the ini-
tial color value and the requisite carbon dosage. This_lack
of correlation is due to the nature of the dyes and their
chemical affinity for the carbon surface relative to their
affinity for water (i.e., their solubility), and to competi-
tion between the dyes and other organic components of the dye
bath for the carbon surface. Also, not much can be said
about the effect of pH on the adsorption of the dyes; in
general, the extent of adsorption of organics on carbon is
known to increase with decreasing pH, but Table 73 does not
support this generalization; no pattern is apparent. The
adsorbability of the dyes on carbon as a function of pH ap-
pears to be specific for each of the systems studied. Even
two dyes of the same class do not behave in the same fashion;
Reactive Red 120 (waste no, 5) was more strongly adsorbed at
acid pH (pH 3,5) while Reactive Red 40 (waste no. 16) was
more strongly adsorbed at neutral pH (pH 6). Wastes 8 and
18, both containing basic dyes, also did not behave uniformly
with respect to the effect of pH, This observed phenomenon
is probably caused by the competitive adsorption of other dye
bath components.
Figure 86 shows the effect of carbon dosage on the reactive
and basic dyeing wastewaters, under the best conditions of
adsorption tested, in an attempt to compare the relative
adsorbabilities of these two dye classes on activated carbon.
Carbon appears to decolorize the basic dyes more efficiently
than the reactive dyes as less carbon was required to effect
a given degree of decolorization. A more suitable means of
comparison is to calculate, for each waste, the amount of
color removed (dye adsorbed) by a given weight of carbon and
to plot this quantity against the residual color (dye concen-
tration) in accordance with the Langmuir adsorption model.
215
-------
TABLE 73. REQUISITE POWDERED ACTIVATED CARBON DOSAGES FOR
BEST DEGREE OF DECOLORIZATION, AND CORRESPONDING
REMOVALS OF TOTAL ORGANIC CARBON
CTi
Dye
class
Reactive
Reactive
Basic
Basic
Acid
Azoic
Acid
(1:2 Metal
Complex)
Disperse/
Acid/Basic
Requisite
PAC
Dyeing dosage,
no. Substrate mg/1
5 Cotton 2500
16 Cotton 1700
8 Polyacrylic 1000
18 Polyester 400
10 Polyamide 1000
20 Cotton 800
2 Polyamide 900
13 Polyamide 500
Carpet
Most
effective Most Initial Final Initial
type of effective color color TOC,
PACa pH value value mg/1
HD-3000b 3.5 3,890 25 150d
HDB, KB 6 1,390 50 230
KB, D-14, 4.5 12,000° 100° 255
D-16
KB, D-14, 7 2,040° 100° 1120
D-16
KB, HDB, 5.1 4,000 260 315
D-14, D-16
D-14, D-16, 4 2,415 100 170
HD-3000
D-16b 6.8b 370 100 400
KB 3 720° 40° 130
TOC
Final Reduc-
TOC, tion,
mg/1 %
20 86.7
140 39.1
140 45.1
800 28.6
175 44.4
135 20.6
-'
325 18.8
50 61.5
aCarbons tested were DARCO HDB, HD-3000, KB, S-51, HYDRODARCO C, and NUCHAR D-14, D-16.
kflnly one type of carbon or one pH tested.
°Prefiltration step omitted.
Initial TOC for adsorption study appreciably less than TOC of raw fresh waste.
-------
COLOR VALUE
Q
C
oo
^ s! o
o &) o
n>
rt-
CD
n
en
DJ C en
H- o
> rt 3
o tr
rt O
H- 5d i-h
< CD
CD tn Sd
rttJ CD
CD CD BJ
QJ O O
rt rt
O H-
OJ rt <
H O CD
CT
OOO
3 CD 3
O DJ
O
M W
O fa
n en
H- I-1-
N o
fu
rt O
H-"
-------
(C0-C)/m = KppC/(l+KC)
where
C0 = initial color (dye concentration)
C = residual (equilibrium) color (dye concentration)
m = weight of the adsorbent (carbon)
K = measure of the strength of adsorption
Q° = adsorptive capacity
Figure 87 is a Langmuirian plot of the data for the reactive
and basic dyeing wastewaters under the best conditions (pH
and type of carbon) of treatment. While it may not be appro-
priate to generalize from the limited results of this study
in which only two reactive dyeing wastewaters and two basic
dyeing wastewaters were investigated, Figure 87 does suggest
that ba,sic dyes are more readily adsorbed by activated carbon
than are reactive dyes. Similar calculations for wastes 10
(acid dye) and 20 (azoic dye) indicate a similar degree of
adsorption for both, and of the same degree as for the basic
dyeing wastewater no. 18. An attempt was made to linearize
the adsorption data to fit a simple Langmuirian or Freundlich
adsorption model, but the linear fit was not satisfactory for
all the wastes, (Actually, there is no reason to expect a
satisfactory fit to either model since "ADMI color" is a
collective parameter expressing the response to several
colored components, each with a different affinity for the
carbon. The presence of other organics in the waste which
compete with the dye molecules for the carbon surface is
another factor negating a simple mathematical formulation.)
Table 73 also shows the TOC removals corresponding to the PAC
doses which give the most efficient decolorization. The per-
cent removals were quite variable, even for the same dye
class (e.g., reactive or basic), ranging from 18% to 87%;
only two of the wastes had removals greater than 50%. It is
apparent that the dye molecules were selectively adsorbed
relative to the other organic components.
Ozonation (Chemical Oxidation)
In order to ascertain which dyeing wastewaters, of those in-
vestigated, were most effectively decolorized by ozone and
to compare the various dye classes as to their susceptability
to decolorization by ozone, Figures 88 and 89 were construc-
ted. For each of the wastes, the results plotted are those
218
-------
H
O
a
to
87
Adsorpti
Dyeing Was
Adsorpt
ion
t
on
of
to
M
^D
_ fD
O 3
CL £u
CD rt n
M CD O
H M
03 O
H
H-
3 Hi
h
> O
o 3
n
o to
h! CD
Ch Q)
QJ O
rt
H-
<
CD
O
fD
£
H-
rt
cr
tr1 W
JU fU
3 tn
3
c
H-
l-S
0
COLOR ADSORBED PER UNIT WT. CARBON,color units/mg
ro -P* o> oo o ro -fr
1 1
o
m \
01
-------
5000
2000
1000
UJ
D
_l
5
ct:
o
o
o
500
200
100
50
•
\ REACTIVE (5)
VAT/DISPERSE
(17)
DISPERSE (14)
-vt DISPERSE (3)
\
DISPERSE (9)
REACTIVE (16)
\
V
5 10 15 20
OZONE APPLIED, gms
25
FIGURE 88. Comparison of Reactive and Disperse Dyeing
Wastewaters with Respect to Decolorization by
Ozone
220
-------
10,000^-
5000
UJ
ID
2000
o 1000
o
o
500
• BASIC (8)
200
100
DIRECT (II)
AFTER COPPERABLE
DIRECT (4)
BASIC (18)
DIRECT
DEVELOPED
(12)
0
5 10 15
OZONE APPLIED, gms
20
25
FIGURE 89, Comparison of Direct and Basic Dyeing Waste-
waters with Respect to Decolorization by Ozone
221
-------
obtained for a 7 scfh flow rate (which generally yielded
about 5% 03 by volume) and those pH conditions giving the
best degree of treatment. Figure 88 clearly shows that the
reactive dyes (wastes 5 and 16) were very efficiently decolor-
ized by ozone, with 5 to 7 gms O3 (approximately 1 gm/1) suf-
ficient to decolorize the waste to less than 100 (95-97% re-
duction in color). The disperse dyes, however, as a class,
were relatively poorly decolorized by ozone (wastes 3, 9, 14
and 17) as shown in Figure 88, Figure 89 shows that the
basic dyeing wastewaters (8 and 18) were quite effectively
decolorized by ozone but that ozonation was unable to decrease
the color below a residual of 200-300 color units. The direct
dyes varied in their susceptability to decolorization by
ozone depending upon the nature of the direct dyeing applica-
tion. Ozone was very efficient in treating the after-copper-
able direct waste (no. 4) and also relatively efficient in
treating the direct-developed waste (no. 12); it was not very
effective, however, in decolorizing the Direct Black 38 waste
(no. 11). This could be due to the high initial color of
waste no. 11 which required a greater quantity of ozone than
the less-intensely colored wastes (compare the slopes for
wastes 11 and 12 in Figure 89) . It is apparent from Figure
89, however, that the basic dyeing wastewater no. 8, with the
same initial color value as no. 11, was much more reactive
toward ozone. Table 74 summarizes the effectiveness of ozone
in decolorizing those dyeing wastewaters investigated. The
basic dyeing wastewaters are categorized as moderately treat-
able only because of the residual color which appeared to be
resistant to ozone. The classifications noted for the other
dyeing wastewaters which are not shown in Figures 88 and 89
can be confirmed by comparing their decolorization responses
to ozone, given by the figures in Section VII and the summary
in Table 66, with the responses of the disperse and reactive
dyes. Again, while it is difficult to generalize based upon
a limited amount of data, it appears that the reactive dyes
as a class are quite responsive to decolorization by ozone
while the disperse dyes as a class are not.
Ozone is known to be a strong oxidant, but for the dyeing
wastewaters investigated, the concentrations of total organic
carbon were unaffected by ozone (see summary in Table 66)
This should not be interpreted to mean that'the specific
organic compounds comprising the TOC were not oxidized by
ozone since TOC is a collective parameter for all organic
species regardless of oxidation state. What the data do mean,
however, is that any oxidation which took place was not com-
plete in converting organic carbon to inorganic carbon di-
oxide. Although the chemical oxygen demand (COD) of the
wastes before and after ozonation was not measured, it might
be hypothesized that the COD decreased as a result of the
222
-------
TABLE 74. SUMMARY; DECOLOR!ZATJON BY OZONE
Very treatable
by ozone
Poorly treatable
by ozone
Moderately
treatable by ozone
Reactive dyeings -
5, 16
1:2 metal complex
dyeing - 2
After-copperable
direct dyeing - 4
Direct developed
dyeing - 12
Disperse/acid/basic
dyeing - 13
Disperse dyeings - Basic dyeings -
3, 9, 14, 17 8, 18
Acid dyeing - 10 Sulfur dyeing - 15
Direct dyeing - 11 Azoic dyeing - 20
Disperse/acid/basic
dyeing - 19
Note:Dyeing wastewaters 1,6, and 7 were not treated by
ozone.
partial oxidation by ozone of the organic compounds compris-
ing the TOC. The fact that the BOD of some of the wastes
increased as a result of ozonation suggests that the organics
were altered in part by ozone, being converted from non-bio-
degradable organics to organic compounds which were biologi-
cally oxidizable. Ozone has been demonstrated by several
researchers to have this effect on organic wastes and one
group5 has even proposed ozone as a pre-treatment step for
dyeing wastewaters prior to biological treatment.
The results in Section VIII suggest that the efficiency of
ozone in decolorizing the various dyeing wastewaters is
largely a function of the gas transfer characteristics of the
reactor system. While no attempt was made to optimize gas
transfer, the data confirm that increased partial pressures
of ozone in the feed gas stream significantly increase the
driving force for ozone dissolution and subsequent reactivity
with the dye molecules. Better mixing in the reactor and a
greater contact opportunity between the injected gas and the
solution can result in a more efficient utilization of ozone
and can decrease the quantity of ozone required to achieve a
desired degree of decolorization.
223
-------
It was also observed that, in general, acidic pH values (with
the exception of wastewater no, 5) provided more effective
decolorization of the wastes by ozone,
COMBINED BIOLOGICAL/PHYSICAL-CHEMICAL TREATMENT
Since the biological systems were generally very effective in
reducing the BOD and TOG of the dyeing wastewaters but rather
ineffective in decolorizing the wastes, and the physical-
chemical treatment systems effectively decolorized the wastes
but generally provided poor TOG and BOD removal, three dyeing
wastewaters were investigated by coupling biological degrada-
tion with physical-chemical decolorization. Following 21
days of biological incubation as described in Section VI, the
samples were filtered to remove the microorganisms and the
resulting liquid was analyzed for TOG, BOD, and ADMI color.
The 100% samples (i.e., full-strength dyeing wastewaters,
undiluted) which had been seeded with acclimated sludge were
then treated by either alum coagulation or powdered activated
carbon adsorption under the appropriate dosage conditions
which had proven to be most effective in the separate physical-
chemical treatability studies. The results are shown in Table
75. Columns 2 and 3 in the Table should be identical, barring
some small changes during storage between treatments. The
combined treatment produced an effluent with greater than 85%
removal of BOD, greater than 70% removal of TOG, and a resi-
dual color of less than 100 (with the exception of no. 18
which could have been decolorized further by a higher dosage
of carbon as was shown in Figure 77).
These coupled treatability analyses suggest that the colored
effluent from biological treatment systems can be subsequent-
ly decolorized by coagulation, carbon adsorption, or ozona-
tion. Alternatively, if the dyeing wastewaters can be seg-
regated in the plant, they can be decolorized by one of these
physical-chemical treatment methods and then combined with
the remainder of the organic wastewaters in the plant and
treated biologically for BOD and TOG removal,
CONCLUSIONS
1, Dyeing wastewaters can be effectively treated with re-
spect to BOD, TOG, and color removal if they can be seg-
regated in-plant,
2. No one specific type of treatment will suffice for all
dyeing wastewaters; the most effective type of treatment
depends upon the type of dyeing performed and the chemi-
cal composition of the dye bath.
224
-------
TABLE 75. RESULTS OF COMBINED BIOLOGICAL/PHYSICAL-CHEMICAL
TREATMENT
Dyeing Wastewater No. 17 - Vat and Disperse Dyes on Polyester/
Cotton
Before After
After phys. chera. phys. chem.
Initial biol. treat. treat. treat.
ADMI color 365
Apparent
color 1100
BOD5, rag/1 360
TOC, mg/1 350
313
38
83
296
364
68
72
155 mg/1 Al with no pH adjustment. Final pH 5.9
Dyeing Wastewater No. 18 - Basic Dyes on Polyester
Before
After phys. chem.
Initial biol. treat. treat.
After
phys. chem.
treat.b
ADMI color
Apparent
color
BOD 5, mg/1
TOC , mg/1
1300
2040
1470
1120
668
216
275
579
1744
__ «> _• —
87
208
— — —
400 mg/1 Nuchar D-16 at pH 6.7.
Dyeing Wastewater No. 20 - Azoic Dye on Cotton
Before
After phys. chem.
Initial biol. treat. treat.
After
phys. chem.
treat.c
ADMI color 2415
BOD5, mg/1 200
TOC, mg/1 170
1987
<1
55
1683
18
:800 mg/1 HD-3000 at pH 6.0
225
-------
3. Disperse, vat, and sulfur dyeing wastewaters can be read-
ily decolorized by coagulation with alum, but are not
readily decolorized by activated carbon.
4. Reactive, basic, acid, and azoic dyeing wastewaters can
be readily decolorized by activated carbon; basic dyes
are more strongly adsorbed on carbon than reactive dyes.
5. Reactive dyes can be decolorized most effectively by
ozone; disperse dyes are decolorized least by ozone.
6. BOD and TOC removal by physical-chemical treatment techni-
ques, i.e., coagulation, carbon adsorption, and ozonation,
is not very effective.
7. The organic constituents of the dyeing wastewaters are
relatively biodegradable and BOD and TOC can be effectively
reduced by biological treatment.
8. BOD removal is, generally, not inhibited by the dye mole-
cules or other components of the dye bath.
9. Color, in general, is not readily removed by biological
waste treatment, suggesting that the dye molecules are
not readily biodegradable.
10. Nitrification fails to occur in some dyeing wastewaters.
This is probably due to (1) presence of organic nitrogen
compounds which resist ammonification and/or (2) inhibi-
tion of nitrification by some component(s) of the waste-
water. The causative agents of the inhibitory action
have not been identified.
11. Dyeing wastewaters can be effectively treated with respect
to BOD, TOC and color removal by coupling biological
treatment with physical-chemical treatment methods, the
former to remove BOD and TOC and the latter for decolori-
zation.
226
-------
REFERENCES
1. EPA. Handbook for Monitoring Industrial Wastewater. U.S.
Environmental Protection Agency, Office of Technology
Transfer, Washington, D. C., 1973.
2. Little, L. W., W. B. Durkin, J. C. Lamb III, and M. A.
Chillingworth. — "Effect of Biological Treatment on
Toxicity of Dyes to Fish." Iri ADMI, Dyes and the
Environment: Reports on Selected Dyes and Their Effects,
Vol. II, American Dye Manufacturers Institute, Inc.,
N. Y. , September, 1974.
3. Abbott, W. E. "The Bacteriostatic Effects of Methylene Blue
on the BOD Test." Water and Sewage Works 95; 424,
1948.
4. Siddiqi, R. H., R. E. Speece, R. E. Englebrecht, and J. W.
Schmidt. "Elimination of Nitrification in the BOD
Determination of 0.01M Ammonia Nitrogen." Journal of
the Water Pollution Control Federation 39: 579-589,
1967.
5. Netzer, A., and H. K. Miyamoto. "The Biotreatability of
Industrial Dye Wastes Before and After Ozonation and
Hypochlorination-Dechlorination," paper presented at
Purdue Industrial Waste Conference, May, 1975.
227
-------
SECTION IX
TEXTILE MILL EFFLUENT SURVEY
There is a paucity of data in the literature on contribu-
tions of dyes to trace metal concentrations in textile
mill effluents. A paper presented by ADMI calculated
theoretically trace metal concentration for a class of
dyes, depth of dyeing, dye bath liquor ratio, degree of
dye exhaust, and water usage for a given application.
Recently, Netzer, Miyameto, and Wilkinson have determined
concentrations of selected heavy metals in exhausted dye
batch effluents. However, the range of dyes and applica-
tions covered in their report is very limited, specifically
to rabbit fur dyeing, and dyeing of acrylic and nylon
fibers.
It was, therefore, decided to undertake an analytical
survey of dye batch wastes from textile mills for cadmium,
chromium, copper, lead, mercury, and zinc. In view of the
general concern whether benzidine is present in significant
amounts in textile wastes, benzidine was included in the
analytical survey. It must be emphasized that the samples
analyzed were untreated samples from exhausted dye baths
without any dilution from other textile operations such
as scouring, rinsing, etc.
A discussion of the procedures used for the heavy metals is
found in Appendix A and for benzidine in Appendix B.
SAMPLING PLAN
Samples of exhausted dye bath liquors along with plant
service water sample were collected from textile mills by
American Textile Manufacturers Institute (ATMI). Textile
mills were selected for parcipitation in this program so as
to represent a broad cross-section of the industry and to
represent the more important types of textile manufacturers.
All samples were collected, preserved, and handled according
to EPA methods for extractable metals. Pyrex glass bottles
of 200 ml capacity with lined plastic caps were used for
sample collection. The small bottle was chosen to minimize
breakage in shipment.
Samples for benzidine analysis were also collected in 200 ml
Pyrex glass bottles and preserved by addition of 25 ml of
concentrated HCl/liter of sample. Only exhausted dye bath
samples were collected. Service water samples were not
analyzed for benzidine.
228
-------
RESULTS
Efforts were made to analyze the samples 14 days after the
date of sampling to minimize variations in reported values
due to shelf time.
For the purpose of interpretation of data, samples have been
grouped by different dyeing systems depending upon the fab-
ric or yarn dyed and the type of dye(s) used. Methods of
application had no significant effect on pollutant concen-
trations in exhausted dye batch effluents and hence, were
not considered as bases for dyeing systems. A total of 22
dyeing systems were thus established.
Following approximations have been used in computing the
delta values between make-up water samples and effluent sam-
ples. Delta value for a given parameter of a sample is de-
fined as Cgampie - cmake-up, where csample and _ ^-make-up
stand for the concentrations of the parameter in effluent
sample and in make-up water respectively.
A. All process water values reported as less
than detection limit are considered as zero
values.
B. All effluent sample values reported as less
than detection limits are considered to be
equal to detection limit concentration.
C. In those cases where, for a given sample
and trace metal, make-up water has a higher
value than corresponding effluent sample, the
value of effluent sample is taken into con-
sideration.
D. If maximum value for a dyeing system is re-
ported as less than detection limit, it is
taken as being equal to detection limit.
E. All minimum values are reported as true val-
ues including those reported as less than de-
tection limit.
Above approximations have been used in order to bias the val-
ues to the higher side, thus giving a worst possible case
situation.
Results have been segregated by the parameter analyzed and
tabulated. Tables 75 through 81 list by parameters the aver-
age values, maximum values, minimum values for each system,
average values for all systems and the total number of sam-
ples analyzed.
DISCUSSION OF RESULTS
Cadmium
229
-------
Out of a total of 21 dyeing systems surveyed, exhausted dye
baths from 16 systems were found to contain an average 0.05
mg/1 or less of cadmium, dye batch effluent from four sys-
tems contained on an average between 0.16 mg/1 to 0.21 mg/1
of cadmium and one system gave effluents containing 7.50
mg/1 average cadmium. The five systems yielding dye bath
effluents higher in cadmium concentrations are Cotton -
Direct; Cotton - Direct, after copperable; Cotton - Fiber
reactive; Viscose - Direct; and Wool - Acid premetallized.
It appears that Direct dyes contain relatively higher amounts
of cadmium than other classes of dyes.
Chromium
A total of 12 dyeing systems out of 21 systems analyzed were
found to give dyeing wastes with an average of less than 0.1
mg/1 of total chromium. Exhaust liquors from six systems
contained average chromium values between 0.1 mg/1 and 0.5
mg/1. Average chromium values ranging from 0.85 mg/1 to
2.71 mg/1 were observed in exhaust liquors from three sys-
tems. These three systems are Polyamide - Acid premetal-
lized; Polyester, Wood - Disperse, Acid premetallized; and
Viscose - Direct. It should be noted that many of the acid
premetallized dyes contain chromium as a complex with dye
molecules rather than as free metal.
Copper
As results in Table 77 indicate, copper was found in aver-
age concentrations of less than 0.1 mg/1 in exhausted dye
baths from 10 dyeing systems. Average concentrations be-
tween 0.1 mg/1 and 1.0 mg/1 were observed in exhaust liquors
from five systems and average concentrations greater than
1.0 mg/1 up to 12.05 mg/1 were found in exhaust liquors of
six systems. These six systems are Cotton - Developed;
Cotton - Direct; Cotton - Direct, after copperable; Cotton,
Polyester - Direct, Disperse; Polyamide - Acid; and Viscose
- Direct. Many of the direct dyes are derivatives of copper
-phthalocyanine which contains coppen as a covalently bound
complex. Also, some of the direct dyes are developed on the
substrate by a treatment with copper salts after dyeing.
This explains the predictably high values for copper obser-
ved in effluents from dye baths containing direct, direct
after copperable, and direct developed dyes.
Lead
This metal is primarily present in dyes as a metal contam-
inant originating from lead lined equipment used in manu-
facturing of dyes. This explains the results that exhaust
liquors from only three systems contained lead in average
concentrations of less than 0.1 mg/1, whereas lead was pre-
sent in average concentrations between 0.1 mg/1 and 1.0 mg/
1 in exhaust liquors from 17 systems. Only one system, Vis-
230
-------
cose - Direct, gave an exhaust liquor with average concen-
tration of greater than 1.0 mg/1.
Mercury
Generally, mercury is present in dyes as a contaminant
coming from many of the common chemicals, such as caustic
soda, sulfuric acid, etc., used in the manufacture of dyes.
Some of the intermediates used in dyes are manufactured
using mercury salts as catalysts and such dyes may contain
small amounts of mercury. Examination of Table 79 shows
that dye bath effluents from 15 systems out of a total of
21 systems analyzed contained on an average less than 1
ug/1 while six systems contained between 1 ug/1 and 3 ug/1
of mercury. These systems are Cotton - Direct; Cotton -
Naphthol azoic; Cotton - Sulfur; Cotton - Vat; Polyamide -
Acid premetallized; and Wool - Acid premetallized.
Zinc
Analytical survey of exhausted dye batch showed rather wide
prevalence of zinc in average amounts greater than 1.0 mg/1,
but less than 4.0 mg/1. It was also observed that zinc was
present in similar concentrations in process water samples
analyzed. Presence of zinc in process water as well as dye
batch effluents can be traced back to widespread use of zinc
phosphates as a corrosion inhibitor. Effluents from eight
systems were found to contain zinc in average concentrations
of less than or equal to 1.0 mg/1, while effluents from 13
systems ranged from 1.0 mg/1 to 4.0 mg/1 in average zinc con-
centrations .
It was observed for those systems based on dyeing of cotton
that concentrations of zinc in dye batch effluents were low-
er than-corresponding concentrations in process water samples.
Benzidine
A relatively small number of direct dyes are presently pro-
duced from benzidine. However, because of general concern
for presence of benzidine in waste waters and receiving
streams, it was included in the analytical survey of dye bath
effluents. Of the 21 systems investigated, 14 systems had
effluents with less than or equal to 10 ug/1 of average con-
centration of benzidine. The remaining seven systems had an
average concentration of between 10 ug/1 and 20 ug/1 benzi-
dine in their effluents.
It should be pointed out that the analytical method for anal-
ysis of benzidine is a sensitive method capable of detecting
a few ug/1 in water samples. However, presence of any color
in the samples causes considerable interference. This is es-
pecially true if the color is yellowish brown and is extract-
able in ethyl acetate, which is used as an extractant.
231
-------
Table 76: SURVEY OF DYEING WASTES FROM TEXTILE MILLS
Cadmium
NO.
Of Samples
Dyeing System Analyzed
l.Acid Dyeable
Rayon-Acid
2. Acrylic-Basic
3 . Cotton-Developed
4 . Cotton-Direct
5 . Cotton-Direct ,
After Copperable
6 . Cotton-Fiber
Reactive
7 . Cotton-Naphthol
Azoic
8 . Cotton-Sulfur
9 . Cotton-Vat
10 . Cotton , Acetate ,
Rayon, Acid Dyeable
Rayon-Direct , Dis-
perse/Acid Premet-
allized
11 . Cotton , Polyester-
Direct, Acid
12 . Cotton polyester-
Direct , Disperse
13.Polyamide-Acid
14 . Polyamide- Acid
Premetallized
15 . Polyamide-Dis-
perse
16 . Polyester-Dis-
perse
17. Polyester Cati-
onic-Basic
18. Polyester, Wool-
Disperse, Acid
Premetallized
19. Triacetate-
Disperse
20 .Viscose-Direct
21. Wool - Acid
2 2. Wood -Acid Pre-
metallized
1
18
3
10
8
15
7
13
16
5
__ _
11
22
7
10
40
7
2
9
•}
9
2
Average
Value
mg/1
0.02
0.03
0.02
0.16
0.21
0.20
0.02
0.01
0.05
0.05
0.05
0.02
0.02
0.02
0.05
0.05
0.02
0.02
0.18
0.04
7.50
Maximum
Value
mg/1
0.02
0.08
0.03
0.44
0.33
0.56
0.05
0.30
0.20
0.11
0.13
0. 10
0.08
0.10
0.55
0.10
0.02
0. 11
0.40
0.1
15.00
Minimum
Value
mg/1
<0.02
<0.005
0.01
<0.005
0.06
<• 0.02
0.01
< 0.01
< 0.005
0.02
0.00
0.00
< 0.01
0.00
0.00
0.01
< 0.02
0.00
0.07
0.01
< 0.005
Total Number of Samples Analyzed: 218
Average of Average Value Column:0.42 mg/1
Weighted Average for all Systems: .115 mg/1
232
-------
Table 77: SURVEY OF DYEING WASTES FROM TEXTILE MILLS
Chromium
NO.
Of Samples
Dyeing System Analyzed
l.Acid Dyeable
Rayon- Ac id
2. Acrylic-Basic
3 . Cotton-Developed
4 . Cotton-Direct
5 . Cotton-Direct ,
After Copperable
6 . Cotton-Fiber
Reactive
7 . Cotton-Naphthol
Azoic
8 . Cotton-Sulfur
9 . Cotton-Vat
10 . Cotton , Acetate ,
Rayon, Acid Dyeable
Rayon-Direct , Dis-
perse, Acid Premet-
allized
}1. Cotton, Polyester-
Direct, Acid
1 2 . Cotton , Polyes ter-
Direct, Disperse
13 .Poly amide -Ac id
14 . Polyamide-Acid
Premetallized
15 . Polyamide-Dis-
perse
16 .Polyester-Dis-
perse
17. Polyester Cati-
onic-Basic
18 . Polyester , Wool-
Disperse , Acid
Premetallized
19 .Triacetate-
Disperse
20 .Vis cose -Direct
21. Wool - Acid
22. Wood -Acid Pre-
metallized
1
20
^
10
9
14
8
13
17
5
__
11
22
7
9
41
7
2
9
3
9
2
Average
Value
mg/1
0.27
0.03
0.04
0.07
0.07
0.12
0.05
0.08
0.07
0.26
—
0.04
0.08
0.85
0.03
0.10
0.05
1.03
0.14
2.71
0.11
0.21
Maximum
Value
mg/1
0.27
0.06
0.06
0.10
0.10
0.75
0.13
0.30
0. 14
0.75
—
0.10
0.29
3.78
0.09
1.70
0.10
2.00
0.98
7.90
0.60
0.32
Minimum
Value
mg/1
0.27
0.00
0.01
(0 .005
<0.05
<0.02
0.01
<0.02
<0. 005
0.02
--
0.00
0 . 00
<0.01
0.00
0.00
0.00
<0.05
0.00
0.07
0.01
<0.1
Total Number of Samples ^
Average of Average Value Column:0.31 mg/1
Weighted Average for all Systems: .152 mg/1
233
-------
Table 78: SURVEY OF DYEING WASTES FROM TEXTILE MILLS
Copper
NO.
Of Samples
Dyeing System Analyzed
l.Acid Dyeable
Rayon-Acid
2 . Acrylic-Basic
3 . Cotton-Developed
4 . Cotton-Direct
5 . Cotton-Direct ,
After Copperable
6 . Cotton-Fiber
Reactive
7 . Cotton-Naphthol
Azoic
8 . Cotton-Sulfur
9 . Cotton-Vat
10 . Cotton , Acetate ,
Rayon, Acid Dyeable
Rayon-Direct , Dis-
perse, Acid Premet-
allized
1,1. Cot ton, Poly ester-
Direct, Acid
12 . Cotton , Polyester-
Direct , Disperse
13 . Polyamide-Acid
14 . Polyamide-Acid
Premetallized
15 . Polyamide-Dis-
perse
16 . Polyester-Dis-
perse
17. Polyester Cati-
onic-Basic
18. Polyester, Wool-
Disperse, Acid
Premetallized
19. Triacetate-
Disperse
20 .Viscose-Direct
21. Wool - Acid
22. Wood -Acid Pre-
metallized
1
20
3
10
9
14
8
13
17
5
__ _
11
22
7
9
41
7
2
9
1
9
2
Average
Value
mg/1
0.05
0. 09
3.93
12.05
11.61
0.23
0.06
0.08
0.37
0.05
1.83
1.43
0.48
0.04
0.16
0.05
0.40
0.08
8.52
0.07
0.05
— .,
Maximum
Value
mg/1
0.05
0.46
6.38
15.10
26.00
1.10
0.13
0.45
0.90
0.12
4.00
14.10
1.65
0.13
0.78
0.10
0.60
0.20
12.40
0.20
0.10
1
Minimum
Value
mg/1
<0.05
0.00
2.66
8.50
1.70
<0.02
0.01
0.02
<0.03
0.00
0.22
0.00
0.00
0.00
0.00
0.00
0.20
0.02
1.01
0 . 00
0.00
Total Number of Samples Analyzed:222
Average of Average Value Column:1.98 mg/1
Weighted Average for all Systems:1.53 mg/1
234
-------
Table 79 : SURVEY OF DYEING WASTES FROM TEXTILE MILLS
Lead
NO.
Of Samples
Dyeing System Analyzed
l.Acid Dyeable
Ray on -Ac id
2 .Acrylic-Basic
3 . Cotton-Developed
4 . Cotton-Direct
5 . Cotton-Direct ,
After Copperable
6. Cotton-Fiber
Reactive
7 . Cotton-Naphthol
Azoic
8 . Cotton-Sulfur
9 . Cotton-Vat
10 . Cotton , Acetate ,
Rayon, Acid Dyeable
Rayon-Direct , Dis-
perse, Acid Premet-
allized
11. Cotton, Polyester-
Direct, Acid
12 . Cotton polyester-
Direct , Disperse
13 . Polyamide-Acid
14 . Polyamide-Acid
Premetallized
15 . Polyamide-Dis-
perse
16 .Polyester-Dis-
perse
17. Polyester Cati-
onic-Basic
18 . Polyester , Wool-
Disperse , Acid
Premetallized
19 .Triacetate-
Disperse
20 .Viscose-Direct
21. Wool - Acid
2 2. Wood -Acid Pre-
metallized
1
20
^
i n
9
14
8
13
17
5
11
22
7
9
41
7
2
9
3
Q
2
Average
Value
mg/1
0.25
0.12
n.15
0.42
0.60
0.54
0.16
0.28
0. 42
0.10
_ mm
0.20
0.21
0.12
0.08
0.18
0.26
0.27
0.15
1.95
n 7?
0.10
Maximum
Value
rag/1
0.25
0.33
0.25
0.80
1.2
1.2
0.40
1.0
1.32
0.18
—
0.40
0.41
0.25
0.25
0.90
0.90
0.33
0.37
3.99
n qn
Minimum
Value
mg/1
CO. 25
0. 00
0.05
0.04
<0.025
0.02
0.00
<0.02
0.02
0.05
--
0.00
0 .00
0.01
0.00
<0.01
0.05
<-0.20
<0.05
0.85
n.02
o.io ro-i
Total Number of Samples Analyzed:222
Average of Average Value Column: 0.32 mg/1
Weighted Average for all Systems 0.27 mg/1
235
-------
Table 80 : SURVEY OF DYEING WASTES FROM TEXTILE MILLS
Mercury
NO.
Of Samples
Dyeing System Analyzed
l.Acid Dyeable
Rayon-Acid
2 . Acrylic-Basic
3 . Cotton-Developed
4 . Cotton-Direct
5 . Cotton-Direct ,
After Copperable
6 . Cotton-Fiber
Reactive
7 . Cotton-Naphthol
Azoic
8 . Cotton-Sulfur
9 . Cotton-Vat
10 . Cotton , Acetate ,
Rayon, Acid Dyeable
Rayon-Direct , Dis-
perse, Acid Premet-
allized
11. Cot ton, Poly ester-
Direct, Acid
12 . Cotton , Polyester-
Direct , Disperse
13.Polyamide-Acid
14.Polyamide-Acid
Premetallized
15 . Polyamide-Dis-
perse
16 . Polyester-Dis-
perse
17. Polyester Cati-
onic-Basic
18 . Polyester , Wool-
Disperse , Acid
Premetallized
19. Triacetate-
Disperse
20 .Viscose-Direct
21. Wool - Acid
2 2. Wood -Acid Pre-
metallized
1
19
3
9
9
12
7
12
16
4
—
11
19
6
7
40
7
2
9
2
8
2
Average
Value
mg/1
0.6
0.39
0.5
1. 39
0.79
0.62
1. 12
1. 15
2.20
0.31
0.79
0. 38
1.23
0.27
0.99
0.43
0.5
0.58
0.50
0.48
1.53
Maximum
Value
mg/1
0.6
0.5
0.5
9.3
1.90
1.50
3.33
5.0
17.0
0.50
_ —
3.96
1.00
5 9
0.5
13.3
1.0
0.5
2.00
0.50
1.0
3.0
Minimum
Value
mg/1
0.6
0.05
<0.05
<0.05
0.11
^0.5
0.20
<0.05
<0.08
< 0.05
0.00
<-0.2
^0.05
0.00
<0.05
"^0.20
<0.5
<-0.02
0.50
C 0.05
^0.05
Total Number of Samples Analyzed: 205
Average of Average Value Column: 0.80 ug/1
Weighted Average for all Systems £1.86 ug/1
236
-------
Table 81 : SURVEY OF DYEING WASTES FROM TEXTILE MILLS
Zinc
NO.
Of Samples
Dyeing System Analyzed
l.Acid Dyeable
Rayon- Ac id
2 .Acrylic-Basic
3 . Cotton-Developed
4 . Cotton-Direct
5 . Cotton-Direct ,
After Copperable
6 . Cotton-Fiber
Reactive
7 . Cotton-Naphthol
Azoic
8. Cotton-Sulfur
9 . Cotton-Vat
10 . Cotton , Acetate ,
Rayon, Acid Dyeable
Rayon-Direct , Dis-
perse, Acid Premet-
allized
11. Cotton, Polyester-
Direct, Acid
12 . Cotton polyester-
Direct , Disperse
13 .Polyamide-Acid I
14 . Polyamide-Acid
Premetallized
15 . Polyamide-Dis-
perse
16 .Polyester-Dis-
perse
17. Polyester Cati-
onic-Basic
18 .Polyester , Wool-
Disperse , Acid
Premetallized
19 . Triacetate-
Disperse
20 Viscose-Direct
21. Wool - Acid
22. Wood -Acid Pre-
metallized
1
20
•3
10
9
1 4
8
13
17
5
__
11
22
7
9
41
7
2
9
^
9
2
Average
Value
mg/1
1.41
1.06
0.66 "\
0.87
1.02
0.65
2.02
0.54
0.83
1.04
—
0.46
1.39
1.78
1.06
1.53
0.46
1.54
1.00
1.32
3.43
3. 10
Maximum
Value
mg/1
1.41
8.67
1.26
1.0
1.50
3.3
3.3
1.82
2.20
2.60
--
1.34
2.35
2.40
1.90
7.27
1.50
1.88
2.10
2.00
8.2
3.69
Minimum
Value
mg/1
1.41
u . uu
0.08
0.48
0.60
0.04
0.2
0.07
0 .05
0.20
—
0.00
0 . 00
0.40
0.10
0.00
0.00
1.20
0.01
0.40
<0.5
2.5
Total Number of Samples Analyzed: 222
Average of Average Value Column: 1.29
Weighted Average for all Systems: 1.22 mg/1
237
-------
Table 82 : SURVEY OF DYEING WASTES FROM TEXTILE MILLS
Benzidine
No.
Of Samples
Dyeing System Analyzed
l.Acid Dyeable
Ray on -Ac id
2 .Acrylic-Basic
3 . Cotton-Developed
4 . Cotton-Direct
5 . Cotton-Direct ,
After Copperable
6 . Cotton-Fiber
Reactive
7 . Cotton-Naphthol
Azoic
8 . Cotton-Sulfur
9 . Cotton-Vat
10 . Cotton , Acetate ,
Rayon, Acid Dyeable
Rayon-Direct , Dis-
perse, Acid Premet-
allized
11. Cotton, Polyester-
Direct, Acid
12 . Cotton , Polyester-
Direct , Disperse
13 . Polyamide-Acid
14 . Polyamide-Acid
Premetallized
15 . Polyamide-Dis-
perse
16 .Poly ester- Dis-
perse
17. Polyester Cati-
onic-Basic
18 . Polyester , Wool-
Disperse , Acid
Premetallized
19. Triacetate-
Disperse
20 .Vis cose -Direct
21. Wool - Acid
2 2. Wood -Acid Pre-
metallized
-
23
1
10
12
18
9
11
1?
5
2
19
24
5
9
49
9
3
9
2
9
2
Average
Value
mg/1
10
16
13.4
16
10
9.1
15
9
6
10
7
11
14
4
14
9
1.67
9.11
10
3.78
10
Maximum
Value
mg/1
10
16
44
44
10
10.0
50
18
10
10
10
20
20
10
60
10
3
20
10
20
10
Minimum
Value
mg/1
< 1
16
<10
<10
<10
^ 2
uo
<. 1
1
<10
1
<10
Mo
< 1
Vi
< i
^ i
*. i
10
< 1
<-10
Total Number of Samples Analyzed:243
Average of Average Value Column: 11.5 ug/1
Weighted Average for all Systems: 11.8 ug/1
238
-------
CONCLUSIONS
In this survey of waste waters from textile dyeing oper-
ations, approximately 220 samples of exhausted dye bath
effluents, representing a total of 22 dyeing systems were
analyzed under carefully controlled conditions for cad-
mium, chromium, copper, lead, mercury, zinc, and benzidine.
Results obtained show that while some of the metals are pre-
sent in significant quantities in exhausted dye bath liq-
uors , especially when these metals are an integral part of
dye molecule, generally dyes do not contribute significant
amounts of metals or benzidine to dye baths. It should be
emphasized that the effluent samples analyzed were untreat-
ed and undiluted samples. In a normal textile mill opera-
tion, these samples would be diluted by other operations
such as scouring by a factor of 100 to 1,000. Further,
these effluents will be treated in a waste water treatment
plant when substantial removal of the trace metals and ben-
zidine would occur. Typically, treated effluent from a
textile mill would contain these trace metals and benzidine
as contributions from dyes in amounts that are 1,000 to
10,000 times smaller than the values observed in this anal-
ytical survey.
REFERENCES
1. American Dye Manufacturers Institute, Textile Chemist
and Colorist, -4(12) , December 1972.
2. Netzer A., H.K. Miyamoto, and P. Wilkinson. Bulletin
of Environmental Contamination and Toxicology. _L4(3) :
301, 1975.
3. U.S. Environmental Protection Agency. "Methods for
Chemical Analysis of Water and Wastes." p. 83. Office
of Technology Transfer, Washington, B.C. 1974.
239
-------
SECTION X
COMPENDIUM
INTRODUCTION
At some point in the manufacture of most textile products,
whether for apparel, home furnishings, automotive fabric
or other use^ a chemical or "wet" processing stage is
necessary to properly purify, color or finish the product
to adapt it for its intended purpose. Such chemical
treatment can result in the production of waste arising
not only from the removal of natural or added impurities
from the fiber but as residue of scouring and bleaching
agents, dyes, chemical products used as "finishes", and
auxiliary chemicals included to facilitate the particular
process involved. Proper technology will minimize the
production of waste from dyes and chemicals.
This survey will provide an overview of textile dyeing
processes together with a description of dyes and chemicals
used in commercial practice. These dyes and chemicals, any
decomposition substances, and contaminants removed from the
textile during dyeing are the chemical contributors to the
water-pollution problem which the dyehouse will have to
control.
Textile fibers are of many chemical types and are wet
processed in many physical forms. Both factors help to
determine the specific chemical treatment which may be
applied.
A. Chemical Categories of Fibers
The chemical categories into which fibers may be divided
are as follows:
Chemical Category Example
Cellulosics Cotton, linen, regenerated
cellulose rayon
Cellulose esters Acetate, triacetate
Proteins Wool, silk
Polyamides Nylon, "Quiana"
Polyacrylics "Acrilan", "Creslan",
"Orion"
Polyesters "Dacron", "Fortrel",
"Kodel"
Polyolefins Polypropylene
Aramide "Nomex"
240
-------
Polyurethane Spandex^
Fluorocarbon "Teflon"
Inorganic Slass/Fiber
It should also be noted that a number of the
non-cellulosic fibers listed above may be chemically
modified by the fiber manufacturer to render them dyeable
with acid and/or cationic dyes.
B. Physical Forms Processed
Textiles are dyed in the following physical forms:
Loose or Staple Fiber -
Discontinuous lengths of man-made fibers cut or broken
into specified lengths from bundles or continuous
filaments (tow). Natural fibers, e.g., cotton and wool,
which have been subjected to no manufacturing processes,
are in this category.
Tow -
Large bundles of nontwisted continuous monofilaments.
Top -
Combed and slightly twisted ropes of wool fiber or
synthetic staple prior to being twisted and possibly plied
to form staple yarn.
Yarn - Filament -
Continuous strands of, usually, multiple filaments. Some
types are textured by the fiber producer or throwster,
i.e., are mechanically treated to acquire twists, turns or
crimp.
Staple -
Short lengths of natural and/or synthetic staple fibers
mechanically twisted and spun into yarns. Filament and
staple yarns may be dyed as skeins or as packages, i.e.,
wound on a perforated spindle or spring. This is usually
the case where the fabric is to be woven or knit into a
fancy or multicolored pattern. Where the warp
(lengthwise) yarns of the fabric are to be all of a single
color, the yarns may be dyed as a beam (wound essentially
parallel to each other on a large perforated spindle or
241
-------
beam through which the dyebath is pumped), a rooe warp
(continuous bundle), or a flat warp (parallel);"in the
last case, the dyeing process is a continuous operation.
Fabric -
May be knit, woven, or nonwoven (interlaced fibers bonded
into a sheet). Fabrics may be processed in the open width
(under some tension), in rope form (relaxed, without
tension), or, in the case of circular knit goods, in
tubular form, i.e., unslit.
Garments -
Hosiery, sweater components. The physical form .will
determine to some extent whether a batch or a continuous
operation will be used in wet processing. For example,
yarn wound on tubes or cones, or individual units of
apparel as hosiery, is not adapted to continuous handling
whereas fabric, depending upon its construction, may be
quite suited to this method.
Obviously, the physical form of the material to be
processed and whether continuous or batch operation is to
be used will in turn affect the design of the equipment in
which the processing is to be carried out.
C. Machines for Dyeing
Dyeing machines may be divided into those used for batch
processing (wherein each unit of the material to be dyed
is subjected to the process over a substantial time
period, often several hours), continuous processing
(wherein an indefinite length of the material to be dyed
is passed rapidly through the processing machinery so that
the exposure at any given point in the material ordinarily
does not exceed a few minutes) and semi-continuous, a
combination of the two.
A very brief description of the basic types of equipment
used for dyeing textiles is given below. Many variations
are encountered. Open, closed and pressurized types are
further options.
1. Batch Dyeing Equipment -
a. Jig - See Figure 90. This is a device for dyeing
fabric in open width (flat) form in which cloth from a
roll is drawn through heated dye liquor and rewound on
another roll. This movement is continued back and forth
until the dyeing is completed, the fabric being in
constant motion. The liquor to goods ratio may be about
four to one.
-------
b Beck - See Figure 91. In this machine a length of
fabric in loose rope form, with ends sewn together to make
a continuous loop is moved round and round constantly
through the heated dyebath. Large becks can handle many
parallel loops of cloth. A variation is a beck for
open-width as opposed to roped fabric. The liquor to goods
ratio may be as high as twenty to one.
c. Skein dyeing machine - See Figure 92. Machines of
this type are designed to keep skeins of yarn in motion
(rotating) while circulating dye liquor through them. Some
machines simply keep the skeins moving in
the liquor. Other types of skein dyeing equipment hold
the skeins fixed on frames while circulating the dyebath
with a pump or propeller.
d. Package machine - See Figures 93 and 94. A "package"
for use on this machine is made by winding a single strand
of yarn on a perforated tube or core. These packages are
placed on perforated spindles in a closed vessel, and dye
solution is forced through the package in alternating
inside-out and outside-in directions by a suitable pump.
e. Beam dyeing machines - See Figure 95. For dyeing
yarn in beam form several hundred parallel ends are wound
onTa large spool or beam with flanged ends. The beam is
then processed much as if it were a single large package
in a package dyeing machine. Some types of fabric may
also be dyed by winding open width on a perforated beam
and then circulating the dye bath through it. See Figure
96. The ratio of liquor to goods on package and beam
dyeing machines may be seven or eight to one.
f Hosiery dyeing machine - See Figure 97. One type of
device for dyeing hosiery is the so-called paddle machine
in which a rotating paddle wheel serves to keep the
dyebath agitated and mesh bags containing the hosiery in
constant motion. Another type consists of a
horizontal perforated drum divided into several
compartments with perforated walls. The drum is loaded
with hosiery and is then rotated in the dyebath, reversing
direction of rotation at intervals. The liquor to goods
ratio is relatively high.
g. Jet dyeing machine - See Figure 98. This utilizes
the same principle as a dye beck in that an endless loop
Of roped fabric is continuously conveyed in and out of the
dye liquor. However in place of a rotating reel a
powerful stream of the treating liquor producing a Venturi
effect in guiding tubes is responsible for moving the
fabric through the dyebath. The powerful jet of dye
solution also provides excellent penetration and intimate
243
-------
FABRIC
GUIDE ROLLERS
DYE VAT
DYE
Figure 90. Dye Jig
REEL
FABRIC
TANK
GUIDE ROLLER
- DYE
Figure 91. Dye Beck
244
-------
PERFORATED ARM
ARM TURNS
-PUMP
Figure 92. Skein Dyeing Machine
FLOW OUTSIDE-IN
FLOW INSIDE-OUT
PRESSURE
GAUGE 4-WAY
VALVE
Figure 93. Package Machine
245
-------
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tn
C
•H
(U
(U
tn
en
0)
tn
fi
•H
QJ
>i
Q
-H
Cn
O
QJ
m
vd
-d-
CM
-------
IOU OF FABRIC
\
/ // / / / / /./../.../..
TANK
PERFORATED BEAM
\
\
CLOTH COVERINC
Figure 96. Beam Dyeing (Fabric)
PADDLE
MESH BAGS
CONTAINING
PIECE GOODS
DRAIN
L
DYE VAT
Figure 97. Hosiery Dyeing
247
-------
JET
UNLOADING REEL
THROTTLE VALVE
METERING ROLLS
LOADING PORT _
HEAT EXCHANGER
ADD DYE TANK
CENTRIFUGAL PUMP-
ADD DYE PUMP
CLOTH GUIDE TUBE
DOFFING JET
LIGHT
CLOTH STORAGE CHAMBER
DRAIN
Figure 98. Jet Dyeing Machine
Figure 99. Padder (Two Types)
248
-------
contact of dye and fiber, improving efficiency and
uniformity.
2. Semi-Continuous Dyeing Equipment -
a. Pad-jig - The pad (see Figures 90 and 99), which is
itself a device for continuous treatment of fabric, may be
used in conjunction with other batch equipment or other
continuous equipment. The pad is simply a device for
rapidly impregnating fabric in open width form with any
treating solution and then squeezing the fabric between
rollers so that a controlled and uniform retention of
treating solution is obtained. Initial saturation of
cloth with dye solution on a padder followed by transfer
to a jig (described above) for development of the shade
over a period of time has proved very satisfactory for
certain dyeings, hence the pad-jig system.
b. Pad-batch - In this system the fabric after
impregnation and squeezing is simply rolled up on a beam
("batched") and allowed to stand for a period of time at
room temperature. Slow rotation of the beam may be
necessary.
c. Pad-roll - See Figure 100. Another system which
provides an extended time for shade development following
continuous padding is similar to "the pad-batch just
described except that provision is made for heating the
padded fabric and storing it under controlled temperature
and humidity conditions in a movable chamber.
3. Continuous Dyeing Equipment -
a. Pad-Steam Range - See Figure 101. This equipment was
designed for the continuous dyeing of open-width fabric
with vat dyes. The most popular arrangement is, as shown,
first to apply an aqueous dispersion of unreduced vat dye
(pigment), dry, pad in an alkaline sodium hydrosulfite
solution, expose to air-free saturated steam for one
minute or less, then oxidize, wash and dry. Cloth speeds
of one hundred yards per minute or so are not uncommon.
b. Thermosol range - Sometimes described as a
"thermo-fixation" unit, this range is based on the ability
of polyester fiber to absorb certain dyestuffs uniformly
(i.e., to dye) under the influence of dry heat. After
being padded with a dispersion of a disperse dye the
fabric is dried, then passed into the thermosol oven where
it is exposed to heat in the range of 390° to 450° F for a
period of 90 to 15 seconds after which the goods are
washed and dried. The thermosol range and the pad-stream
range (3,a above) are commonly combined to dye in one
249
-------
Saturator
Storage slowly
rotating
Figure 100. Pad-roll Machine
Pad dispersed
pigment
Dry
Chemical
pad
Steamer
30 sec
218*F
Wash Soap Wash
Oxidizer
Figure 101. Pad-steam Range
250
-------
passage blended fabric comprised of polyester and
cellulosic fibers. See Figure 102.
c. Carpet dyeing range - The difference in physical
structure between carpets and other woven or knitted
textiles requires a modified handling system for
continuous dyeing. One such system is the
Butterworth-Kusters range shown in Figure 103. The carpet
is first wet out with chemicals (usually including a
latent foaming agent), then the dye is metered to the
surface of the carpet by a doctor blade arrangement which
is furnished by a roll revolving in slightly thickened dye
liquor. The carpet progresses to a loop steamer where it
is festooned so that no contact is made with the carpet
face. Dyeing takes place in the steamer, after which the
carpet is washed free from excess dye and chemicals.
d. Indigo dyeing range for yarn - See Figure 104.
Cotton yarn in the form of rope warps is dyed continuously
with indigo in the sequence of operations shown. Each box
or vat, usually holding 2,000 gallons or more is equipped
with guide rollers and has squeeze rolls at the exit end.
Between and above the dye vats, rollers are suspended for
"skying" or air oxidation of the previously applied indigo
solution which has been put into its reduced state by the
addition of sodium hydrosulfite and sodium hydroxide.
After the required number of reduced dye - air oxidation
cycles a boiling water wash is usually given, then the
warps are run over steam heated cylinders to dry them.
PREPARATION OF TEXTILES FOR DYEING
A. Impurities to be Removed
In order to be successfully dyed, printed, or otherwise
finished, textile fibers must first be put into a
reasonably pure state, that is, most of their natural
impurities and any foreign matter accidentally or
deliberately introduced in processing must be removed. The
method by which this step is accomplished will depend upon
the nature of the fiber.
Impurities associated with the various fibers are listed
below.
Cotton
Motes - small pieces of foreign vegetable
matter.
Spinning Oil - a hydrocarbon oil or other oily
material applied as a lubricant
251
-------
OVEN
DRY CANS
PAD
QJ C
D
Q_d
a c
INFARED
PRE-DRYER
PAD
BOX WASHER
Figure 102. Thermosol, Pad-steam Range
WET CHEM.
OUT PAD
STEAMER
WASH BOXES
Figure 103. Carpet Dyeing Range
252
-------
OXIORE
2} min. 2j min. 2j mm. 2{ min. *1 mm. 2| min.
UM>
\
\,
•OH.
•OX
n
MC
L A A
1 T
RINSE
19
MC
DENIM
VAT
SO
MC.
-
,
DENIM
VAT
SO
MC.
rf
DENIM
VAT
SO
MC.
t.
ft
DENIM'
VAT
SO
MC.
_
k
DENIM
VAT
SO
MC.
t
ifl
DENIM
VAT
50
MC.
51
,
DRYING T
10 minutl
a
RUNNING
WASH
16
MC.
k A
RUNNING
WASH
IS
MC.
Figure 104. Indigo Dyeing Range
253
-------
to staple fibers to facilitate
spinning.
Warp size - a glutinous solution, e.g., of
starch, polyvinyl alcohol, or
acrylic resin, applied to impart
smoothness and strength to warp
yarns to enable them to withstand
mechanical abrasion during weaving.
Protein
Ash
Pectins
Wax
Pigment
Wool
Grease - a fatty wax coating the fiber surfaces.
Suint - dried perspiration of the sheep, rich in
potassium salts.
Sand and dirt
Burrs and other vegetable matter
Spinning oil
Warp size
Synthetics
Finish applied by the fiber producer
Oily and carbonaceous matter from machines
Warp size
Spinning oil
Tint - a colorant applied by the producer or
spinner to identify certain yarns.
B. Chemical Processes Applied to Textiles Before Dyeing
1. Desizing -
254
-------
Desizing is a process in which starch-based warp size is
hydrolyzed by acid or digested by enzymes to render it
soluble in water and therefore readily removable by
washing. Polyvinyl alcohol and acrylic sizes are usually
removed directly in scouring.
2. Scouring -
Scouring consists of a hot alkaline treatment in which
oily, waxy or greasy material or acquired impurities as
well as some ash, pectins and protein, if present, are
removed from fibers. The action can involve
saponification and emulsification as well as simple
solution of the impurities in the alkaline liquor.
Scouring with chlorinated hydrocarbon solvents is also
used to some extent.
3. Carbonizing -
Carbonizing is used to remove unwanted vegetable matter or
fibers from wool in stock or fabric form. The action
takes place by deliberately drying acid into the material
under conditions which will decompose the vegetable
materials to a friable powder ("carbon") which can be
beaten out of the goods.
4. Bleaching -
Bleaching is used to destroy residual natural color in
fibers remaining after the scouring process. It is an
oxidation process usually effected with hydrogen peroxide
or sodium hypochlorite.
5. Mercerizing -
Mercerizing is the treatment of cotton yarn or fabric,
while under tension to prevent shrinkage, with sodium
hydroxide solution in the concentration range of 16 to 25
percent. The goods are rinsed nearly free of alkali
before the tension is released. The result is a cotton
fiber which has a desirable subdued luster and
substantially greater dyeability.
The equipment used for the above preparatory operations
may be either of the batch or of the continuous variety;
the latter predominates and in general consists of a
sequence beginning with a pad for impregnation with
chemicals followed by some type of conveying system in
which the goods are carried through steaming or heating
units while the chemicals act, then neutralizing and
washing as necessary. In the case of fabric mercerizing,
the cloth as it moves is held under tension until most of
the sodium hydroxide solution is washed out.
255
-------
Typical sequences in the preparation of the important
fibers are as follows:
Cotton: Desizing, scouring, bleaching,
mercerizing (optional)
Wool; Scouring, carbonizing, bleaching
(optional)
Synthetics; Scouring, bleaching (optional)
DYEING
A. Definition
A dye can be loosely defined as a chemical compound which
when properly applied to a substrate from solution or fine
dispersion will color it with some degree of permanence.
Normally the process is not merely a surface coloration
but a cross-section of the substrate will be found to be
uniformly penetrated and colored.
B. Classifications
There are in excess of 2,000 known dyes, some 1,400 being
regular articles of commerce in the United States as
indicated in PRODUCTS 75.*
The Colour Index+ divides all dyes into 22 more or less
distinct chemical classes, some of the more important of
these being for example azo, anthraquinone, stilbene,
triarylmethane, azoic, and methine. Of greater value to
the dyer is a classification based on usage or method of
application. Included in this system are acid, direct,
developed, mordant, metal complex, basic (or cationic),
disperse, vat, soluble vat, sulfur, reactive, azoic (or
naphthol), oxidation dyes, and pigments. The class names
indicate to the dyer both the fibers to which each is
applicable and the method by which it is applied.
*A buyers guide to US producers and suppliers of dyes,
pigments and chemical specialties for the textile wet
processing industry published annually by the American
Association of Textile Chemists & Colorists.
+ Third edition. 1971. Published jointly by the Society
of Dyers and Colourists (England), and the American
Association of Textile Chemists and Colorists (USA).
256
-------
Table 83 will serve to relate the usage or application
class of dyes to the fiber types upon which they may be
applied; it also illustrates the overlapping and diversity
of their chemical constitutions. Reference to the Colour
Index under the "constitution numbers" shown usually will
provide the exact chemical structure of a dyestuff.
C. Mechanisms; Principles
The mechanisms by which dyes are absorbed and retained by
textile fibers are exceedingly complex.
In general, dyes in solution or in a finely dispersed
state are preferentially absorbed by a fiber substrate in
the dyebath. The forces responsible for the attraction and
retention of the dye molecule by the fiber may be chemical
(secondary valence forces, ionic charges, covalent bonds),
or physical, or both. Such factors as time, temperature,
pH and the presence of auxiliary chemicals (e.g.
electrolytes, solvents, surface active agents) may affect
the efficiency of a given dyeing process and the
uniformity with which the dye is absorbed.
From a physical standpoint it is necessary that all
surfaces of the material to be dyed be furnished
continuously with dye solution. This can be done either
by moving the material through the dye liquor or by
forcing the dye liquor through the material. This is the
basis on which machines for dyeing are designed. As for
all wet processing, the dyeing machine must be adapted to
the physical form of the goods.
To bring about dyeing in a reasonable length of time, the
rate of diffusion of dye molecules into the substrate
fiber is frequently accelerated by raising the dyebath
temperature. Elevated temperatures also facilitate uniform
distribution of dye throughout the material being dyed.
In the case of the more hydrophobic synthetic fibers
accelerated dyeing may be accomplished by (a) the use of
organic substances known as carriers and/or (b) the use of
closed dyeing systems allowing dyeing temperatures as high
as 150°C.
Continuous dyeing methods may be used where the production
volume is sufficient to provide economic justification and
the mechanical structure of the material permits. These
involve a series of steps commencing with the uniform
impregnation of the material with the dye solution or
dispersion under conditions which minimize substantive
absorption. Subsequently, the material may be dried and
then heated at elevated temperatures to effect diffusion
257
-------
TABLE 83
CLASSIFICATION OF DYES* BY USAGE AND CHEMICAL NATURE
Chemical
Class
Stilbene
Quinoline
Machine
Ox.Tzino
_ArUhraaulnone
Pht hfl 1 ocyan ine
Afr Idlne
_Dit>henylmeth*ne
_Th i*zole
Inilamlne,
Indonhenol
Azine
Thlazine
Sulohur
Azoic
Indigo Id
Nltroso
Uitro
Trinrylinethane
Xiint}ien<»
Inrtomlne,
indophenol
Colour Inde>
Constitution
Numbers
11000-36999
40000-40999
47000-47909
4^000-48999
51000-51999
50000-72999
74100-74999
46000-46999
41000-419-J9
49000-49399
49400-49999
50000-50999
52000-52999
53000-54999
37000-39999
73000-73999
10000-10299
10300-10')99
42000-44999
45000-45999
49400-4U999
Celluloalc
Di-
rect
X
X
X
X
X
X
X
X
sul-
fur
X
X
X-
X
X
x
X
Naph-
thol
X
X
Vat
X
X
X
X
X
Reac-
tive
X
X
X
X
X
Fiber Types
Prote in
Acid
X
X
X
X
X
X
X
X
X
X
X
Mor-
dant
X
X
X
X
X
X
X
Cellulose
Esters
Dis-
perse
X
X
X
X
X
Polvamide
Veld
X
X
X
X
X
X
X
X
X
X
Dis-
perse
X
X
X
X
X
Cat-
ionic*
X
X
X
X
X
X
X
X
X
X
X
X
Polyester
Dis-
perse
X
X
X
X
X
Cat-
ionic*
55
X.
X
X
X
X
X
X
X
X
X
X
Pe
Acid
X
X
x
X
X
X
x
x
X
X
X
lyacrylie
Dis-
perse
X
x
Y
x
x
x
Cat-
ionic
x
x
Y
x
x
x
NO
cn
oo
•Pigment colorants, applicable to any fiber by a reein bonding process but chiofly used on cotton, are not included here.
Motei The classes of dyea listed under each fitor typo represent the important usage. Infrequently, dyes not cuntomarily
employed on a given fiber may be used, possibly with special application methods. E.g., vats on wool, naphthols on polyester.
cationics on cellulosics, etc.
•• Applicable only to "cationic dyeable" fiber.
-------
of the dye into the fiber, as in the thermosol process.
In other cases as for example with vat and sulfur dyes,
with or without drying the material is next impregnated
with chemicals which will convert the dye to a substantive
form, and then it is steamed to diffuse the substantive
dye into the fiber; in a following unit a chemical
treatment may be employed to insolubilize the absorbed dye
within the fiber.
D. Properties of Dyes and Methods of Application
As can be noted in Table 83, different fibers can often be
dyed with the same dye class. This table also shows that
several chemical classes of dyes are often found in one
usage or application class. Therefore, in the information
given below, emphasis is primarily on the application
class of dyes and its properties, with appropriate
references to the fiber types for which the class may be
used The following information for the most part has
been adapted from the preambles to the respective sections
in the Colour Index.
1. Direct Dyes -
Direct dyes are used generally because of economics and
ease of application. These dyes were originally designed
and marketed for dyeing cotton and are defined as "Anionic
dyes substantive to cellulose when applied from an aqueous
bath containing an electrolyte." They color cellulosic
materials from a neutral or slightly alkaline bath, at or
near the boil, to which sodium chloride or sulphate is
added in such quantities and at such intervals of time
appropriate to the dyeing properties of individual dyes.
The majority of direct dyes belong to the Dis-, Tris- and
Polyazo classes, the remainder being Monoazo, Stilbene,
Oxazine, Thiazole, and Phthalocyanine compounds.
Some direct dyes have extensive use also on paper,
leather, wool, silk, nylon, bast fibers and for many
miscellaneous purposes.
Direct dyes may be processed or designed specifically for
the following after-treatments (after the initial dyeing
process) for improvement in fastness properties:
a. development on the fiber to a more complex
dye through diazotising and coupling with a
developer such as beta-napthol.
259
-------
b. aftertreatment on the fiber with salts of
metals, such as copper or chromium, to form
metal complexes.
c. aftertreatment on the fiber with
formaldehyde.
d. aftertreatment on the fiber with a cationic
dye complexing agent.
2. Vat Dyes -
Vat dyes are used generally for their high fastness
properties, particularly resistance to hypochlorite
bleaching on cellulosic fibers.
These dyes, with very few exceptions, fall into two
clearly defined groups, indigoid and anthraquinonoid.
Included in the former are indigo, thioindigo and their
derivatives while the latter include derivatives of
antnraquinone as well as heterocyclic quinones
Characteristic of all these compounds is the ketonic group
>C-0 which, on reduction, forms the leuco derivative
>C-OH. As leuco compounds are capable of forming
water-soluble alkali metal salts, the water-insoluble vat
dyes may be brought into solution by reduction in alkaline
liquor, in which form they exhibit affinity for textile
fibers; subsequent oxidation reforms the insoluble
dyestuff.
Vat dyes are available from manufacturers as finely
divided water-insoluble pigments and as such they have no
true affinity for fibers. They may be applied to fibers
in the sodium leuco form, produced by first "vatting" the
dye in the presence of sodium hydrosulfite and sodium
hydroxide. The affinity of this reduced dye for fiber is
so high however that it is often desirable in order to
avoid non-uniform dyeing, to distribute the finely divided
pigment form of the dye throughout the goods, then
introduce the chemicals necessary to bring about reduction
and consequent dyeing. After the dye has been absorbed by
the fiber, it is reconverted to the insoluble pigment
state within the fiber by oxidation with an agent such as
hydrogen peroxide, then soaped and rinsed. The initial
distribution of dye pigment can be by batchwise or by
continuous methods. If the former, the rate of deposition
(or exhaustion") of the pigment onto the fiber surfaces
from the aqueous dispersion may be controlled by the
addition of electrolyte to the pigmentation bath.
Pre-pigmentation of loose fibers, yarn packages, knitgoods
on the beck, and woven fabrics on the beam dyeing machine
260
-------
is a valuable aid to level dyeing in aqueous development
processes.
In continuous applications the initial step is uniform
impregnation on a padder with dispersed vat dye pigment.
In fact the pigment-padding process is the basis for most
continuous vat dyeing procedures, e.g., pad-steam. Here
the pigmented cotton fabrics, preferably pre-dried, are
passed through a cold padding liquor containing caustic
soda and sodium hydrosulphite. Reduction and fixation are
achieved by steaming at atmospheric pressure, e.g., 30
seconds at 100-105°C. This is followed by continuous
oxidation and soaping treatments as part of the continuous
sequence.
If the sodium leuco compounds are acidified, acid leuco
compounds can be prepared. Such compounds possess even
less affinity for the fiber than dispersed pigment and
have been used to enable level dyeings to be obtained from
dyes which possess so great an affinity that they are
difficult to apply evenly by the normal process.
3. Sulfur Dyes -
Sulfur dyes are used in deep shades for econqmic reasons
and fastness to washing. They are employed to produce a
wide range of shades on cotton and rayon and to some
extent on synthetic blends.
Sulfur dyes are made from organic compounds with nitro and
amino groups by reactions with sulfur or sodium sulfide at
high temperatures. Although sulfur dyes have been made
and used for over 75 years, definite chemical structures
have not been established for many of them.
The mechanism of dyeing is very similar to that of the vat
dyes in that they are converted to the soluble leuco form
by chemical reduction. Specifically, alkaline sodium
sulfide is used for this purpose.
Sulfur dyes are commonly available in liquid form,
pre-reduced, so that other than the liquid dye all that
ordinarily need be added to the dyebath is electrolyte.
If an unreduced form of the dyebath is purchased it is
boiled with a strong solution of sodium sulfide together
with sodium carbonate to reduce and dissolve it. Again,
common salt or sodium sulfate is used as electrolyte in
the batch dyeing process. After the dye has been absorbed
by the fiber it must be converted back to the insoluble
form by an oxidation step. Dye in the pre-reduced leuco
stage may also be applied by a continuous system. A
slight excess of sodium sulfide is normally present during
261
-------
application. The fabric is padded, steamed, or dryed and
washed. Oxidation for either batch or continuous method
is accomplished by treatment with sodium bichromate,
hydrogen peroxide, sodium perborate or potassium iodate.
A variation of the continuous process is to pad on
unreduced pigment, dry, pad with sulfide, steam, oxidize
and wash.
4. Azoic Coloring Matters
These products are used primarily to produce bright
shades, principally reds, with good washfastness and which
in many cases are fast to bleaching.
The products referred to are those used to produce
insoluble azo dyes (commonly called "naphthol" dyes in the
trade) in situ on a textile substrate, usually cotton.
The basic principle of their application is the
introduction of two small soluble components into the
fiber and the use of suitable conditions for coupling to
occur, resulting in the production of one larger,
insoluble colored molecule. One component is selected
from the available Colour Index Azoic Coupling Components
and th,e second from the Colour Index Azoic Diazo
Components. The latter are diazotised primary amines, or
the parent amines when the dyer caries out the
diazotisation. The former are often known as naphthols
because the majority are derivatives of B-naphthol, and
some commercial products have been sold under this name.
The azoic coupling component is insoluble in water and
must be converted to the soluble salt, e.g., the sodium
salt, by means of caustic soda, usually with the aid of
sulfonated oils, alcohol or Cellosolve. Formaldehyde may
be added to stabilize this solution.
Azoic diazo components are marketed in two main forms:
(1) as the free base, hydrochloride or sulphate of a
primary amine which must be diazotised in the normal
manner for such chemical compounds; (2) as stabilized
diazo compounds generally referred to as "Salts". These
Salts need only dissolving in cold water to be ready for
use, saving the dyer the time and trouble of
diazotisation.
As the textile material containing azoic coupling
component normally also contains excess alkali, and diazo
salts are unstable at high pH, it is usually necessary to
arrange for neutralization and buffering. The Salts
contain the necessary agents to provide the correct
conditions for many applications but it is desirable,
especially when pad developing, to calculate the quantity
262
-------
of additional "alkali-binding agent" that may be required.
Excess acid is avoided as it reduces the rate of
coupling.
Dyeing is normally carried out in two stages, impregnation
with an alkaline solution of the azoic coupling component
being followed by immersion in a solution of the azoic
diazo component. The first stage may be carried out on
loose fibers, yarn and fabric by batch methods that is,
over a period of time, during which the naphthol is
absorbed by the fiber, on the normal batch dyeing
machines. Fabric may also be impregnated continuously by
padding usually followed by immediate drying.
The textile material containing the coupling component (or
"naphthol") is then brought in contact with the diazotized
base or "salt" solution either in the same piece of
equipment in which the naphtholation took place or any
suitable processing device. The coupling reaction
normally takes place very rapidly. After coupling, the
material is well rinsed and then treated at the boil in
alkaline detergent solution to remove any loosely held dye
and to develop the true hue and maximum fastness
properties of the dyed material.
5. Reactive Dyes -
Fiber-reactive dyes are generally used for their high wet
fastness and brightness.
Fiber-reactive dyes are capable of forming a covalent
chemical bond with textile fibers. These dyes are
combined with cellulosic fibers through an alkaline system
and are combined with wool, nylon and silk by means of an
acid system. The most important area of application is to
cellulosic fibers.
The major fiber-reactive groups are:
Monochlorotriazinyl
Dichlorotriazinyl
Monochlorodifluoropyrimidinyl
>-
2,4-Dichloropyrimidinyl
2,4,5-Trichloropyrimid inyl
2,3-Dichloroquinoxaline-6-carbonyl r
263
-------
Chlorobenzothiazole (linked to the dye molecule
via -COHN-, -SC>2NH-, -NH- or -N=N-)
5-Chloro-4-methyl-2-methylsulphonylpyriraidinyl
Vinylsulphonyl
B-Sulphatoethylsulphonyl
B-Sulphatoethylaminosulphonyl
B-Chloroethylsulphonyl
B-Sulphatopropionamido
The first reactive dyes for cellulosic fibers red on the
market in 1956 as a result of the very that dyes
containing a dichlorotriazinylamino substituent can be
applied to cotton and other cellulosic fibers under midly
alkaline conditions, and that the dyes become attached to
the fiber by chemical union with the cellulose molecule.
It is necessary to bring about reaction with only a few
of the many hydroxyl groups in the fiber (even for deep
dyeings); mild conditions are suitable for this purpose.
The dichlorotriazinyl-substituted dyes are often so
reactive that they can be applied to cellulosic fibers by
a cole dyeing process. The second of the two chlorine
atoms is less readily replaced than the first, and if at
some stage of manufacture of the dye one of them is
removed, a monochlorotriazinyl derivative is obtained
with lower reactivity than that of the dorresponding
dichlorotriazinyl compound; such a dye can still react
readily with cellulosic fibers, but requires hot application,
In presence of alkali dyes of both types become attached
to the fiber by covalent bonds; as the dye and fiber then
form a single chemical entity, the coloured product is
highly resistant to wet treatments. Since fiber structure
is not significantly affected, the change in fiber
qualities is negligible.
Many other reactive systems can be applied similarly, but
most have lower reactivity than the dichlorotriazinyl-
amino dyes and, with few exceptions, the dyes need hot
conditions for application.
The processes used vary widely, but fall broadly into
batch, semi-continuous (or pad-batch) and continuous
types. Fixation is effected by means of a variety of
alkaline treatments, the temperature used depending on the
264
-------
reactivity of the dye in use. Unfixed dye is removed
afterwards in a detergent bath, and finally the dyed
material is rinsed with water.
Most reactive dyes are hydrolyzed to some extent during
application; the resulting hydroxy derivatives are no
longer able to react with cellulose. Some affinity for
the fiber remains, but hydrolyzed dyes have low fastness
to wet treatments. It is therefore necessary to remove
unfixed dye by means of a bath containing soap or other
detergent. Reaction takes place mainly with the fiber
rather than with water, however, probably due to the rapid
adsorption of dye molecules by the fiber.
The reactive dyes for wool are based on a system differing
from those used in cellulosic dyes; it has the advantage
of not being subject to hydrolysis in the dyebath.
Reactive dyes are normally applied to wool from neutral or
weakly acid baths. In order to obtain maximum washing
fastness, prolonged boiling, dyeing under pressure, or a
final pH of 8.0-8.5 may be required, but these more severe
conditions may cause some damage to the fiber.
Reactive dyes for nylon were first introduced in 1959.
They are applied in weakly acid conditions, under which
reaction with the fiber does not occur, and level dyeings
are readily obtained; on treatment with alkali, reaction
with the fiber takes place and the resulting dyeings have
high fastness to wet treatments. Free amino groups in the
nylon fiber provide reactive sites, but there is some
evidence suggesting that reaction may also occur with
amide groups.
6. Acid Dyes -
Acid dyes are water-soluble anionic dyes that are applied
to nitrogenous fibers such as wool, silk, nylon and
modified acrylic fibers from acid or neutral baths.
Attachment to the fiber is attributed at least partly to
salt formation between anionic groups in the dyes and
cationic groups in the fiber. A complete range of hues
can be obtained, many of them being very bright, and the
fastness properties vary from poor to very good.
Wool is dyed in all forms, e.g., loose wool, slubbing,
yarn, knitted and woven fabrics, felts and garments. Dyes
with good leveling properties find their chief use of
yarns and fabrics, but dyes with inferior leveling
properties and good fastness to wet processing can be used
satisfactorily on loose wool and slubbing.
265
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When applied on silk and nylon, acid dyes vary in
properties in much the same way as on wool.
The three main methods for application of acid dyes are
characterized by dyebath conditions as follows:
1. Nearly neutral (pH approximately 7.0-5.5)
2. Weakly acid (pH approximately 5.5-3.5)
3. Sulphuric acid (pH 3.5)
The last of these is used on wool, never on nylon.
A special group of acid dyes, called chrome dyes, will
react with chromium salts or with bichromate to form a
metalized dye. Usually, the metalization is effected
subsequent to absorption of dye by the fiber, although
with some dyes the metalizing compound is added with the
dye to the dyebath. Chroming frequently alters the dyed
shade, but enhances fastness to light and to washing.
Some azo dyes may be applied as pre-formed cobalt or
chromium complexes.
7. Disperse Dyes -
Disperse dyes are used on acetate, triacetate, nylon,
"Qiana" nylon, polyester, polypropylene and polyvinyl
chloride fibers and, to a limited degree on acrylic
fibers. For some of these fibers they constitute the only
practical dye system available. Certain anthraquinone
dyes on acetate and triacetate react with oxides of
nitrogen in the air; substantive inhibitors are coapplied
with these dyes to minimize the shade change which would
result from reaction between the gases and the dye.
These dyes are introduced into the dyebath as a fine
dispersion. These dispersions of essentially
water-insoluble azo, diphenylamine and anthraquinone
compounds are produced by grinding with a surfactant or
dispersant, e.g., a naphthalene sulfonic acid-formaldehyde
condensate or lignin sulfonate.
Fine uniform dispersion is necessary to distribute the dye
evenly throughout the dyebath, prevent filtration of the
dye by the fibers being dyed and more specifically to
present a large surface area of dye particles from which
rapid dissolution may take place to replace that taken up
by the fiber during dyeing.
266
-------
Many proprietary carrier compositions or emulsions are
offered to enhance absorption of disperse dyes by
polyester fibers at the atmospheric boil or their leveling
at elevated temperatures in pressurized dyeing vessels.
The active agents of such carrier compositions are
selected from various aromatic classes including biphenyl,
alkyl naphthalenes, chlorinated benzenes, phenyl phenols,
butyl benzoate, methyl salicylate, etc.
Dyes containing primary amino groups may be diazotized and
developed on the fiber to produce dyeings of varying
fastness according to the developers used. This procedure
is widely used in the production of blacks.
After the dyeing has been completed, it may be necessary
to remove residual carrier by means of (1) heat treatment
or (2) scouring the goods in the presence of alkali (NaOH)
and a reducing agent (^28204).
8. Basic Dyes -
These are dyes which yield colored cations in aqueous
solution. They are .often referred to as cationic dyes.
Many of the earliest synthetic dyes, including Perkin's
Mauve, the first dye to be produced commercially from coal
tar, were basic dyes. Perkin himself was largely
responsible for devising the standard methods of
application of these dyes to the fibers then available,
namely silk, wool and cellulosic fibers (mainly cotton).
The appeal of these basic dyes lay in their brilliant
hues, some of them being fluorescent. Because of their
poor fastness properties, particularly to light, basic
dyes were largely superseded following the development of
other classes of dyes having superior fastness properties.
Basic dyes were retained to a small extent for dyeings
where brightness was all-important.
The advent in 1950 of acrylic fibers gave the basic dyes a
new lease of life. Many existing basic dyes were found to
be much faster to light on these fibers than on natural
fibers. This led to the introduction of complete ranges
specifically designed for application to acrylic fibers.
Anionic dye-sites have been introduced by fiber
manufacturers into nylon and polyester fibers, and some
basic dyes have been developed specifically for dyeing one
or more of these modified fibers.
Basic dyes are water-soluble, but in most cases solution
is facilitated by pasteing the dye with acetic acid and
water. Dyebaths require addition of acetic acid.
267
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E. Chemical Assistants Used in Dyeing
In the preceding section, a number of chemicals used as
assistants in the dyebath have been mentioned. Some
additional general comments on chemical additions to
dyebaths is in order. Dyestuffs are seldom if ever
applied as the sole constituents of the dyebath. Acids or
alkalis may be used to adjust the pH, to aid in dissolving
the dye, to speed up the dyeing process or to cause
reaction to take place. Salts may be added to accelerate
dyeing or to slow it down depending upon the dyeing
system. Reducing agents and oxidizing agents are each
essential for certain types of dyeing. A variety of
surface active agents are employed to wet out the goods,
to retard dyeing, to disperse dye, to cause foaming or
prevent foaming, to act as emulsifying agents, as
anti-migrants, dye leveling agents, etc. There are many
hundreds of such products on the market under proprietary
names. These agents are listed by use category and by
proprietary names in the annual products index ("A buyers
guide to U.S. producers and suppliers of dyes, pigments,
and chemical specialities for the textile wet processing
industry") published by the American Association of
Textile Chemists and Colorists. In the annual editions
prior to 1976, some indication of the chemical nature of
these products is also furnished.
F. Removal of Dyes from Fibers (Stripping)
If after completion of a normal dyeing process the dyeing
is found to be off-shade, too dark, uneven or otherwise
inadequate, it may be necessary to remove some or all of
the dye from the fiber. Depending upon the degree of
stripping desired, the chemical nature of the dye and of
the fiber, one or more of the following stripping methods
are most commonly encountered:
(a) Reductive strip with alkaline sodium
hydro-sulfite or acidified zinc
sulfoxylate formaldehyde.
(b) An oxidative strip with sodium hypochlorite
or sodium chlorite.
(c) A combination of either of the above with a
carrier (for polyester).
(d) A carrier/hydrocarbon solvent emulsion
under pressure (for polyester).
268
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G. Dyeing Fiber Blends
Very large quantities of finished textiles contain more
than one fiber type. Blending of fibers in yarn and
fabric is carried out for a variety of reasons, e.g.,
economics, aesthetics, physical performance
characteristics, and to produce special color effects in
dyeing. The selection of dyes and proper dyeing methods
is a problem for the dyer and when two fibers are in the
blend, he is presented with three options, (a) dye one
fiber and leave the other white (reserved), (b) dye both
fibers but in different or contrasting colors (cross
dyed), or (c) dye both fibers the same color (union or
solid shade). When the blend consists of more than two
different fibers, the options are obviously increased.
However, the effect of fiber blends on dyeing effluents is
no more than the sum of the effects of dyeing the fibers
separately.
Doubtless the specific blend produced in the greatest
quantity today is polyester-cotton, and will serve as a
case in point. Figure 102 illustrates a continuous
process for dyeing such blends and merely combines the
pad-steam range for applying vats to cotton with the
thermosol range for applying disperse dyes to polyester.
PRINTING
Textile printing is a textile processing area which may
contribute significantly to effluents from textile plants
but is not within the scope of the present project.
In general, printing carried out by roller or screen
methods or by other means, is a method of producing a
colored pattern effect on textiles which amounts to
localized dyeing. The chief difference between it and
ordinary dyeing, other than the mechanical means of
transferring the color, is that the dye solutions are more
concentrated.
Proper printing viscosity, essential to confinement of the
dye to the pattern being reproduced on the textile, is
usually achieved by incorporation of thickening agents,
e.g., starches and/or natural gums. In some cases
water-in-oil and oil-in-water emulsions are used as
thickeners. After printing and dye fixation, the
thickeners, as well as loose color and any residual
chemicals, are removed by washing.
FINISHING
As the term implies, finishing is a final processing
operation following preparation and dyeing or printing.
269
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There are scores of finishing agents and many methods by
which they may be applied. Again, the AATCC Products
Index is a good initial source of information on these
products. Basically, finishes are applied to improve
either the aesthetics or the utility, or both, of the
textile material. The finish may be temporary or durable,
may be a simple additive or may bring about chemical
modification of the substrate. A finish applied on dyed
textiles may affect the appearance of the color to some
extent and it can occasionally improve or impair fastness
properties.
Some of the commoner finishes are for the following
purposes: hand modification (softening or stiffening),
dimensional stabilization, durable press, water
repellency, flame-retardance, mildew-resistance, moth
proofing, static-electricity control.
Finishes sometimes applied by the dyer, usually in the
rinse following the dyeing, include:
(a) Antislip agents, e.g., methacrylate resins,
polyvinyl alcohols, polyvinyl acetates, to
impart body and inhibit yarn distortion.
(b) Antistatic agents, e.g., polyoxyalkylene
esters, higher alkylamines, or fatty acid
amides which provide temporary antistatic
protection to goods.
(c) Atmospheric - Fading Protective Agents,
e.g., organic amines, to react with oxides
of nitrogen absorbed from the atmosphere.
Gases would otherwise react with and alter
shade of dyes, particularly anthraquinone
blues on acetate.
(d) Fixing Agents, e.g., aliphatic polyamines,
resinous copper complexes,
dimethylol-ethylene urea resins and other
resins, to enhance washing fastness of
direct dyes on cellulose fibers and acid
dyes on nylon.
(e) Flame Retardants, e.g., halogenated organic
compounds, organic phosphorus compounds, to
impede flammability.
(f) Lubricants, e.g., wax emulsions, polyoxy-
ethylene - fatty acid derivatives, to
facilitate winding, knitting, and sewing.
270
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(g) Softener, e.g., long chain alcohol
sulfates, higher alkyl amines and esters,
long chain mono and polycations to impart
soft hand.
Other finishes are applied in a separate area of the plant
subsequent to dyeing. Usually, application is effected by
padding or impregnation, frame drying and, sometimes,
curing. Included would be durable-press resins, water
repellents, soil release and repellent agents, and hand
modifiers.
271
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SELECTED BIBLIOGRAPHY
The following texts provide background information on
textile dyeing:
Dieserens, L. Chemical Technology of Dyeing and Printing.
Volumes I and II. Translated from the 2nd German
edition by Wengraf, P. and H. P. Bauman.
Reinhold, New York. 1951.
Vickerstaff, T. The Physical Chemistry of Dyeing. 2nd
Edition. Interscience Publishers, New York. 1954.
Weber, F. and F. Gasser. Die Praxis der Barberei.
Springer-Verlag, Wien. 1954.
Hall, A. J. A Handbook of Textile Dyeing and Printing.
National Trade Press, London. 1955.
Lubs, H. A. (Editor). The Chemistry of Synthetic Dyes
and Pigments. Reinhold, New York. 1955.
Cockett, S. R. and K. A. Hilton. Dyeing of Cellulosic
Fibres. Leonard Hill, London. 1961.
Bird, C. L. The Theory and Practice of Wool Dyeing. 3rd
Edition. The Society of Dyers and Colourists,
Bradford. 1963.
Schmidlin, H. D. Preparation and Dyeing of Synthetic
Fibres. Translated by Meither, W. and A. F.
Kertess from the German Edition. Chapman & Hall,
London. 1963.
Wilcox, C. C. and J. L. Ashworth. Whittaker's Dyeing
with Coat-Tar Dyestuffs. 6th Edition. Balliere,
Tindall & Cox, London. 1964.
Procion Dyestuffs in Textile Dyeing. Imperial Chemical
Industries, Ltd., Dyestuffs Division, Leeds. 1962.
Cheetham, R. C. Dyeing of Fibre Blends. D. van
Nostrand, London. 1966.
Agster, A. Faberer und Textilchemische Untersuchungen.
Springer-Verlag, New York. 1967.
Trotman, E. R. Dyeing and Chemical Technology of Textile
Fibres. 4th Edition. Griffin, London. 1970.
Rys, P. and H. Zollinger. Fundamentals of the Chemistry
and Application of Dyes. John Wiley, London. 1972.
272
-------
Bird, C. L. and W. S. Boston. (Editors). The Theory
of Coloration of Textiles. The Society of Dyers and
Colourists, Bradford. 1975.
273
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APPENDIX A
PROCEDURES FOR TRACE METALS ANALYSIS
TRACE METALS
Procedure
Samples were sent to analytical laboratories of six partici-
pating companies.
Each laboratory analyzed the samples on or about the 14th day
after the samples were prepared. The concentrations of cadmium,
chromium, copper, lead and zinc were measured using the stand-
ard Environmental Protection Agency method for Extractable
Metals . Sample size was decreased from 100 ml to 50 ml to
minimize breakage in shipment of large samples. This procedure
involved adding hydrochloric acid to the sample which already
contained nitric acid added at the time of collection. The
solutions were heated for 15 minutes at 95°C. After this treat-
ment solutions were filtered if necessary and the above metals
were measured by atomic absorption spectrometry (AAS). Mercury
was determined by the EPA cold vapor technique. Triplicate
measurements were made on each solution.
Effect of Digestion Procedure
EPA reports-'- that data obtained by the procedure for Extractable
Metals "are significant in terms of "total" metals in the sample,
with the reservation that something less than "total" is actually
measured." In order to determine the amounts of metals that
might be missed, a sample of exhausted dyebath liquor was also
analyzed for Cd, Cr, Cu, Pb and Zn by the EPA method for Total
Metals1. Table Al compares results obtained by these two pro-
cedures.
The data for this sample did not indicate any significant defi-
ciency in the EPA Extractable Metals procedure for measuring
total Cd, Cr, Cu, Pb and Zn in dyebath liquors. This correlated
with previous experience of Laboratory E on analyses of other
dyebath liquors. While the comparison analyses were not always
performed in the same laboratories, subsequent "round-robin"
274
-------
TABLE Al. COMPARISON OF DIGESTION PROCEDURE
EPA Extractable Metals EPA Total Metals
(mg/1) (mg/1)
Lab C Lab E Ave. Lab A Lab C Aye.
Cd
Cr
Cu
Pb
Zn
0.02
1.8
0.02
<0.2
0.04
0.01
1.59
0.01
0.10
0.05
0.02
1.70
0.02
<0.15
0.05
<0.01
1.9
0.03
0.03
0.05
0.02
1.6
0.02
0.09
0.05
<0.02
1.75
0.03
0.06
0.05
analyses showed good interlaboratory correlation so these com-
parisons are considered valid.
Analysis of Standard Samples
Standards containing known amounts of metals were analyzed by
participating laboratories at the beginning and end of the pro-
ject in order to check accuracy and interlaboratory precision.
The first standard was prepared by adding known amounts of
metal salts to a dyebath exhaust liquor. Table A2 presents re-
sults for the unspiked exhaust liquor while Table A3 gives delta
values; i.e., data obtained for the spiked dyebath exhaust
liquor minus data obtained in the same laboratory for the un-
spiked liquor. Laboratories A and C did not analyze the un-
spiked liquor. Average values from Table A2were used to
correct their data for the original concentrations.
275
-------
TABLE A2. ANALYSIS OF UNSPIKED DYEBATH LIQUOR NO, 1
All data in mg/1, except for Hg which is yg/1
Cd
Cr
Cu
Pb
Zn
Hg
B
0.01
(0,11)*
0.08
0.05
0.19
D
<0.01
0.08
0.22
<1.0
E
0.02
0.03
0.08
0.02
0.10
<0.5
F
<0.02
0.08
0.12
<0.5
Ave.
0.02
<0.02
0.08
0.04
0.16
<0.6
*Data in parentheses not included in calculation of average
TABLE A3. ANALYSIS OF SPIKED DYEBATH LIQUOR NO. 1
All data in mg/1, except for Hg which is in yg/1. Data
corrected for concentrations of metals found in unspiked dye-
bath liquor
Laboratory
Cone .
Added
Cd
Cr
Cu
Pb
Zn
Hg
1.
1.
1.
1.
1.
10.
00
00
00
00
00
00
A
0.95
0.93
0.77
1.05
0.86
7.0
B
0.86
0.89
0.92
0.97
0.99
____
C
1.00
1.03
1.08
1.02
0.88
6.0
D
1.08
1.00
0.84
0.80
0.98
10.0
E
1.09
0.96
0.84
1.08
1.09
8.0 (
F
1.00
(0.25)
0.44
0.80
0.88
:<0.5)
Ave.
1.00
0.96
0.82
0.95
0.95
7.8
S.
0.
0.
0.
0.
0.
1.
D.
09
06
21
12
09
7
Data in parenthese not included in calculation of average
and standard deviation (S.D.). Test for excluding data from
Reference 2.
276
-------
There was some question regarding the stability of standard
samples prepared from a dyebath exhaust liquor. For compari-
son, a second standard was prepared by addition of known
amounts of metal salts to water distilled in an all-glass
still. Results for this standard are shown in Table A4. The
concentration levels in the second standard were chosen to
be in the ranges encountered in mill samples.
TABLE A4. ANALYSIS OF SPIKED DISTILLED WATER
All results in mg/1, except for Hg which is in yg/1
Cone .
Added
Cd
Cr
Cu
Pb
Zn
Hg
0
0
0
1
5
2
.10
.50
.50
.00
.00
.0
A
0.10
0.48
0.53
0.98
5.23
1.0
B
0.10
0.50
0.50
1.00
6.00
<0.5
C
0.10
0.47
0.55
0.09
6.10
0.5
D
0.04
0.50
0.50
0.80
3.80
2.5
E
0.10
0.40
0.51
1.00
5.00
2.0
F
0,12
0.52
0.50
0.90
5.20
2.2
Ave.
0.09
0.48
0.52
0.96
5.22
1.5
S.
0.
0.
0.
0.
0.
0.
D.
03
04
02
10
83
9
Accuracy and precision in Tables A3 and A4 compare favorably with
values reported by EPA1 at comparable levels except in the case
of mercury.
ADMI data for mercury are as precise as those reported by EPA
but recoveries are lower. Since it is well known that dilute
mercury solutions are not stable unless properly preserved,
it was suspected that this was the reason for low results. As
a result, a special mercury standard solution available from the
National Bureau of Standards (No, 1642) was sent to each labora-
tory for analysis. This solution was stabilized by N.B.S.
by the addition of gold.
277
-------
TABLE A5. ACCURACY AND PRECISION
All data in mg/1, except for Hg which is in yg/1
EPA Data ADMI Data
Added Found S.D. Added Found S'.D.
Cd
Cr
Cu
Pb
Zn
Hg
0
0
0
0
0
9
3
.078
.407
.332
.367
.310
.6
.40
0.
0.
0.
0,
0.
9.
3.
074
380
324
377
308
1
41
0.
0.
0.
0.
0.
3.
1.
018
128
056
128
114
57
49
1.
0.
1.
0.
1.
0.
1.
1.
1.
5.
10.
2.
00
10
00
50
00
50
00
00
00
00
0
00
1.00
0,09
0,96
0.48
0.82
0,52
0.95
0.96
0.95
5.22
7.8
1.5
0.
0.
0.
0,
0.
0.
0.
0.
0.
0.
1.
0.
09
03
06
04
21
02
12
10
09
83
7
9
TABLE A6. DETERMINATION OF MERCURY IN NBS STANDARD NO. 1642
1.118 yg/1
Laboratory Hg Found, yg/1
A 1.5
B 1.0
C 0.5
D 3.2
E 1.0
F 1.8
Aye. 1.5
S.D, 0.95
278
-------
TABLE A7. STABILITY OF SAMPLES
All results in mg/1, except for Hg which is in yg/1
Sample:
Date
Analyzed;
E03001M2
E12003M2
E01020M2
7/2/75 7/28/75 6/27/75 7/21/75 7/22/75 7/31/75
Cd
Cr
Cu
Pb
Zn
Hg
0.
0.
0.
1.
0.
1.
25
06
27
15
20
5
0.
0.
0.
0.
0.
0.
25
06
25
05
19
1
0
0
0
0
0
0
.04
.03
.05
.05
.26
.2
0
0
0
0
0
™
.04
.02
.03
.05
.25
_ __ _
<0.
0.
0.
-------
APPENDIX B
PROCEDURES FOR BENZIDINE ANALYSIS
BENZIDINE ANALYSIS
Procedure
The method used was an adaptation of the chloramine-T oxidation
procedure described in several references (1,2,3); it is de-
scribed in Table Bl. The method differs from the reference
only in extracting solvent and extracting techniques. The
method was written to be applicable to a variety of dyebath
exhaust liquors.
Basically, the method uses ethyl acetate to pre-extract the
sample under acid conditions. This removes the ethyl-acetate
soluble interfering colors. The remaining aqueous-acid sample
is then treated with chloramine-T reagent to oxidize any benzi-
dine present. The oxidation product is extracted with ethyl-
acetate and the absorbance determined on the extract. The
absorptivity is calculated and compared with the absorptivity
of pure benzidine oxidized, extracted and measured in the same
manner.
In establishing the method, variations in extracting solvents
and pH were investigated in order to minimize the interfering
effects of dye bath residues. No single technique was found
that would work well for all the types of samples encountered.
The interference due to color present might be overcome in
some instances by adjusting the method to the sample type. Ad-
justing the method was not possible in this endeavor because
the sample size was limited and only one analysis for benzidine
could be performed on each sample.
The Chloramine-T procedure for benzidine is specific. The
colored compound formed has a characteristics sharp absorption
maxima at 436 nm in ethyl acetate. Other substituted 4, 4'-
diaminodiphenyls also produce intense absorption but the wave-
lengths are shifted sufficiently to differentiate from the
benzidine derivative. Benzenoid amines offer no interference.
The spectrophotometric absorption curve is shown in Figure Bl.
280
-------
TABLE Bl. PROCEDURE FOR THE DETERMINATION OF BENZIDINE IN
TEXTILE MILL DYE BATH EXHAUST LIQUORS
1. Place 200 ml of sample in a Squibb type separatory funnel.
2. Add 25 ml of 2N hydrochloric acid. Check for acidity
with test paper.
3. Add 50 ml to 100 ml of reagent grade ethyl acetate. The
amount used depends on the amount of extractable color
present.
4. Shake well; allow the layers to separate; draw off the
water layer into a clean beaker and discard the ethyl
acetate layer,
5. Return the water layer to the separatory funnel,
6. Add 1 ml of a 10% aqueous solution of Chloramine-T (pre-
pared fresh, weekly), shake, let stand for two minutes.
7. Add 35 ml of ethyl acetate. Shake to extract the color
formed.
8. Separate the ethyl acetate layer into a clean beaker and
return the acid layer to the separatory funnel.
9. Repeat steps 6, 7 and 8 two more times.
10. Filter the extracts by gravity through dry filter paper
into a graduated cylinder. Mix well and record the volume.
Obtain the absorbance of the extract (within 5 minutes)
at 436 nm using a 1 cm cell. A full curve from 380-500 nm is
desirable. Background color will be present in some samples and
a full curve is necessary to correct for background absorption.
Calculation
Ait3 6 x ml in end volume of ethyl acetate x 106 =
ml sample x agtd
yg/1 as benzidine base (MW 184)
a , = the absorptivity of the oxidation product of pure benzi-
s dine extracted and measured in a similar manner. Value
of a . -, is approximately 475 but should be determined
individually by the analyst.
281
-------
~ 2
. ...r..~t~ . t~ r "1 "t~":T
.
380 400 20 40 60 80 500 20 40 60 80 600 20 40 60 60 700
WAVELENGTH IN NANOMETERS J |
Figure Bl. Spectrophotometer curve of benzidine oxidized
with chloramine T and extracted with ethyl acetate,
282
-------
Stability of Sample
Standard samples containing benzidine were sent to the parti-
cipating laboratories in order to establish the variation in
analysis. The prepared samples were found to deteriorate
with time, yielding erratic results. Laboratory investigation
revealed that hydrochloric acid, reagent grade, added to the
samples at the rate of 25 ml per liter produced a stable solu-
tion. The actual experiment consisted of storing several
solutions of dye bath exhaust liquors, preserved with HC1 and
unpreserved, containing 120 yg of benzidine per liter, under
fluorescent lights for one week. The solutions were then
analyzed for benzidine with the following results:
Container pH Benzidine, yg/1
Clear Glass Bottle 7.0 82
Acid-HCl 123
Brown Glass Bottle 7.0 90
Acid-HCl 121
The sample stored in clear glass at pH 7 dropped to 16 yg/1
benzidine at the end of two weeks under fluorescent lights.
Another sample in clear glass was stored in the dark for two
weeks at pH 7 and dropped only to 111 yg/1 benzidine. Data
show that HC1 preserved samples are stable for a period of
two weeks.
CONCLUSIONS
Samples stabilized with HC1 were prepared with dye bath exhaust
liquor from a dyeing of Direct Black 38 spiked with 500 yg/1
of benzidine. A sample of Direct Black 38 contaminated with
free benzidine was used to make the dyeings, which accounts for
the unspiked analyses listed below.
Sample Lab 1 Lab 2 Lab 3 Ave_._ S^EK
Unspiked 23 29 21 24 4
Spiked with 500 yg/1 588 464 490 514 65
After all of the textile mill samples had been analyzed another
final set of standard samples were sent out to two participating
laboratories. This time 4 stabilized samples were involved
prepared with laboratory dye bath exhaust liquors containing
zero, 50, 100 and 200 yg/1 benzidine. The results are as
follows :
283
-------
yg/1 benzidine added
0
50
100
200
Lab I
0
58
118
264
Lab 2
54
80
197
Ave.
0
56
99
230
The precision indicated is to be expected from the type of
samples tested. The standard samples and all of the samples
received from the textile mills contained residuals from the
dyeing operation. The method will detect a few yg/1 when
applied to benzidine spiked distilled water, but the dye
bath liquors actually tested preclude this kind of sensitivity.
REFERENCES
1. Classman, J. M. and J. W. Meigs. Benzidines: A Micro-
Chemical Screening Technique for Estimating Levels of
Industrial Exposure from Urine and Air Samples. A.M.A.
Arch. Indust. Hyg. 4_: 519, 1951.
2, Butt, L. T. and N. Strafford. Papilloma of the Bladder
in the Chemical Industry. Analytical Methods for the
Determination of Benzidine and B-Naphthylamine. J.
Appl. Chem. 6^, December, 1956. ~~
3. Sciarini, L. J. and J. A. Mahew. A Rapid Technique for
Estimating Benzidines in Industrial Exposure. A.M.A.
Arch. Indust. Hyg. 11: 420, 1955.
284
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APPENDIX C
BIODEGRADABILITY PROCEDURE
Preparation of Samples
1. Mix dyeing wastewater thoroughly. Collect 12 liters
in a glass container.
2. Titrate a 100 ml aliquot to determine the approximate
amount of acid or base (NaOH or HCl) required for
neutralization. Then, adjust pH to 7 . 0 .
3. Prepare 10 liters of 1% wastewater by adding 100 ml
of sample to 9900 ml of distilled water.
4. Add nutrients to the dye solution in the following
order:
a. 10 ml CaCl2 stock solution (27.5 g/1)
b. 10 ml MgSO. . 7 H?O stock solution (22.5 g/1)
c. 10 ml FeCljj stock solution (0.25 g/1)
d. 10 ml of phosphate buffer
Stock solution (per liter, 8.5 g KH-PO. , 21.75 g
KHP0/ 33.4 g NaHP0 . 7 H0, 1.7 g NHC1)
e. 10 ml of yeast extract (2.5 g in 50 ml distilled
water)
Obtain 250 ml of seed from each pilot unit (see E,
below)
(Unit 1: activated sludge seeded with activated
sludge from Durham and fed Durham or Chapel Hill
wastewater. Unit 2: as above, but fed wastewater
supplemented with the dyeing wastewater) . Allow
to settle for 15 minutes. Concentrate to 100 ml
by removing 150 ml of supernatant.
Label two 3-liter flasks as #1 and #2. Use flask #1
to prepare A and B mixtures. Use flask #2 only for
C mixture.
Dispense into flask 3 liters of dyeing wastewater
dilution with added nutrients.
a. To prepare A series add 30 ml activated sludge.
Mix thoroughly. Dispense one liter to each of
two 2-liter flasks. Retain remainder for initial
analyses.
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b. To prepare B series, proceed as in la but
inoculate with acclimated activated sludge.
8. Prepare C series in a similar manner, omitting
seeding^ and adding HgCl- solution (2 g/500 ml) .
9. Prepare 10% and 100% series in similar manner by
making appropriate dilutions as in Step 3.
10. Cover mouths of flasks loosely with aluminum foil.
11. Enclose flasks in cardboard containers to prevent
exposure to light,
12. Place flasks on shaker (^80-90 rev/min).
B. Preparation of Samples for Initial Analyses
1. Filter approximately 250 ml of sample using glass
fiber filters (Reeve-Angel) in a filtration apparatus
(In some cases, 0.8 ym pore-size membrane filters
were employed).
2. Submit filtered sample for soluble TOG and soluble
BOD analysis (BOD's are not performed on C series).
3. Dispense 100-200 ml of unfiltered sample into a
brown glass bottle for color analysis.
4. Dispense ^100 ml of unfiltered sample into 125
nalgene bottles, add 1 ml HgCl2 solution for preser-
vation. Submit for analysis or nitrogen forms.
C. Preparation of Samples for Final Analysis
1. After 21 days of incubation at 20 C, remove samples
from shaker for final analysis.
2. Prepare and analyze samples as in B.
D. Interim Sampling on 10% Series
1. Remove samples from 10% dilution series (A, B, C) on
Monday, Wednesday, and Friday.
2. Filter vLO ml of each sample through a glass fiber
filter.
,,3. Submit samples to the laboratory for soluble TOG
analysis.
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E. Design and Maintenance of Activated Sludge Pilot Units
1. Pilot units were two-liter Nalgene graduated cylinders
2. To each cylinder was added 600-800 ml of activated
sludge from the Northside Wastewater Treatment
Plant, Durham, N.C. Bring up to 1500 ml of raw
sewage (from Durham).
3. Units were aerated with forced air.
4. The control unit (A, unacclimated) was fed raw
sewage daily. For feeding, aeration was discontinued
for 30-45 minutes to allow settling of the sludge.
The supernatant was then siphoned off and discarded
and the remaining volume was restored to 1500 with
sewage.
NOTE: Sewage was warmed to room temperature before
addition.
5. The acclimated unit (set #B) was fed raw sewage
supplemented with dyeing wastewater.
In each case, the unit was acclimated gradually beginning on
day 1 with a 1:20 dyeing wastewater/sewage ratio (5%). The
ratio of dyeing wastewater was increased by 5% daily up to
25% (1:4 dyeing wastewater/sewage ratio). Units were
acclimated for 1 week prior to biodegradability testing.
287
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APPENDIX D
CHARACTERISTICS OF POWDERED ACTIVATED
CARBONS TESTED
The characteristics of the powdered activated
carbons tested in the physical-chemical treat-
ment studies described in Section VII are
shown in Table Dl.
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TABLE Dl. CHARACTERISTICS OF POWDERED ACTIVATED CARBONS TESTED
NJ
CO
Type of
Powdered
Carbon
Nuchar D-14
Nuchar D-16
Hydro Darco B
Hydro Darco C
Hydro Darco
3000
Darco KB
Darco S-51
Manufacturer
Westvaco
Westvaco
ICI-United States
ICI-United States
ICI-United States
ICI-United States
ICI-United States
Total
Surface area
m2/gm
1222
1294
550
550
600
1500
600
Iodine
No.
_ __
550
550
600
1300
600
Molasses
No.
•_ —» «•
310
310
310
630
330
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APPENDIX E
SAMPLE CALCULATIONS FOR DETERMINATION OF OZONE CONTENT
OF FEED GAS
The gas mixture from the ozone generator was bubbled through
two traps containing potassium iodide in series for a period
of 2.0 minutes. Aliquots from each of the traps were than
titrated with standardized sodium thiosulfate, using starch
as an end-point indicator. Since the gas flow rate is
known, the ozone content of the feed gas to the reactor
can be calculated.
The relevant reactions are:
Adsorption: QS + 2I~ + H20 + °2 + T2 + 2OH~
Titration: I2 + 2S2O3~2 -*• 2I~ + S4O6~2
From the stoichiometry of these reactions, it can be seen
that 1 mole of thiosulfate is equivalent to 0.5 moles of
ozone. If 0.1 M Na«S?03 is used as the titrant, then each
ml of Na-S-O., is equivalent to
i ™i Ma «? n v 0.1 moles q o 0.5 moles O 48 gms O
1 ml Na~S«O_ x — 1 • j. ^ — Na0b0uQ x _ - _ £_ x _
223 liter 2 2. j
_ _ _
mole NaSO mole
= 2.4 mg 0_ or 5 x 10 moles O-, .
Sample Calculation:
Gas Flow Rate - 7 standard cu. ft/hr (scfh)
Absorption Time - 2.0 minutes
Volume titrated - Trap 1 - 50 ml
Trap 2 - 50 ml
Total Volume in trap - Trap 1 - 300 ml
Trap 2 - 300 ml
Titrant (Na2S203) strength - 0.1 M (2.4 mg Og
Volume of titrant required - Trap 1 - 16.75 ml
Trap 2 - 0.10 ml
290
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Ozone flow rate - 16'75 + ° -1 ml Na2S2°3 x 2'4 m = 1>?%
cu ft gas
291
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TECHNICAL REPORT DATA .
(Please read Instructions on the reverse before completing)
1. REPORT NO. 2. ;
EPA-600/2-78-098
4. TITLE AND SUBTITLE Textile Dyeing Wastewaters : Charac-
terization and Treatment
7. AUTHOR(S)
Roderick H. Horning
9. PERFORMING ORGANIZATION NAME AND ADDRESS;
American Dye Manufacturers Institute
One East 57th Street
New York, New York 10022
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
; Research Triangle Park, NC 27711
. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
May 1978
6. PERFORMING ORGANIZATION CODE
10. PROGRAM ELEMENT NO.
1BB036
11. CONTRACT/GRANT NO.
Grant R803174
13. TYPE OF REPORT AND PERIOD COVEF
Final; 6/74 - 9/75
14. SPONSORING AGENCY CODE
EPA/600/13
15 SUPPLEMENTARY NOTES IkJRL-RTP project officer is Max Samneia, man urop
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