EPA-600/2-78-072 March 1978 Environmental Pr Series
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EPA-600/2-78-072
March 1978
REMOVAL OF COLOR, DETERGENTS
AND OTHER REFRACTORY SUBSTANCES
FROM TEXTILE WASTEWATER
by
Jerzy Kurbiel
Po,ish institute ofMeterology and Water Management
Cracow Division
Cracow, Poland ,
Public Law 480, SFC 055323
Program Element No. 1BB61U
EPA Project Officer Max Samfield
Industrial Environmental Research Laboratory
Office of Energy, Miner* and Indusry
Research Triangle Park, N-C. 27 m
Prepared for
US ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, B.C. 20460
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ACKNOWLEDGMENTS
Headquarters ?L / -°m th6 Office ° Internat on
Project Officer up £ • "" "ntrfbutton «as S by Mr TlfairS' Wash1"9ton
i ne TO i Tnwi MM _.».- j-f.
the IMWM, Cracow Division
Erndt .
Janina Juszczak ......
E^bieta Konstanty " " " " '
Emilia Petlicka-Raj.' ......
Ma/gorzata l^aczka. ......
Krzysztof Tflrschmid .......
Edward Wiekfera. .' .....
From Cracow Technical University:
Kazimiera Broniewska
Wies/aw
analytical research
adsorption
filtration
hyperfiitration
ion exchange
coagulation
coagulation
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ABSTRACT
The following report, covering the period from June 30, 1972 to June
29, 1977, was submitted in fulfillment of Contract No. PR-5-532-3 by the
Water Renovation Section, Institute of Meteorology and Water Management,
Cracow Division, under the sponsorship of the U.S. Environmental Protection
Agency.
The laboratory and pilot scale research was carried out in order to
determine the effectiveness and economic feasibility of selected, advanced
physicochemical treatment processes for the removal of color, detergents,
and other refractory pollutants from wastewater. The subject of the re-
search was mixed textile and municipal wastewater that had previously been
biologically treated by means of activated sludge. The advanced tertiary
processes studies included:
Filtration on single and dual media filters (anthracite and sand),
conventional and contact coagulation,
adsorption on granular activated carbon,
oxidation with ozone,
ion exchange on anionic and cationic resins, and
hyperfiltration (reverse osmosis) on spiral ROGA membrane.
All the processes were investigated both individually and in combined
systems. Each process was initially tested on a laboratory scale and
finally examined on a pilot scale at the experimental plant situated at the
municipal wastewater treatment plant in Andrychow. The total amount of the
raw wastewater according to the last assessment in 1976 was on the average
12,000 m3/d. The proportion of textile to municipal wastewater was main-
tained within the range of 1:1 to 2:1. The research showed that all the
processes studied succeed to a considerable degree in the removal of indi-
vidual pollutants, although the feasibility of the processes as determined
by economic factors, energy consumption, and technical availability differs.
The filtration of biologically treated wastewater reduces the concen-
tration of suspended solids to below 10 mg/1, which represents a 30 to 75
percent removal of the wastewater BOD. Contaminants like COD, color, and
detergents, that are characteristic of textile wastewater, are eliminated
only to a small degree. Aluminum salts with oxidant and acid added for pH
control should be used for coagulation. Contact coagulation in an upstream
filter appears to be a better method than conventional coagulation.
The detailed investigation of the adsorption process has proved that
the color substances present in biologically treated wastewater determine
the proper kind of carbon, while the COD load determines the adsorption
m
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capacity of the carbon. The removal of particular pollutants expressed in
percentage is more complete for biologically treated and coagulated waste-
water than for effluent treated only biologically.
The greatest energy consumption takes place in the hyperfiltration
process as a result of very high wastewater pumping head. The energy con-
sumption in ozone oxidation is also considerable, but this process is less
effective than adsorption in the removal of COD. The ion-exchange process
revealed considerable disadvantages: in particular, poor removal of COD and
a large amount of post-regeneration wastewater.
In the last period of research, a combined system was investigated.
Contact coagulation on upflow filters and dual media filtration preceded by
chlorination with NaOCl and followed by adsorption on activated carbon as a
final process was found to be the most effective of the combined technologi-
cal processes.
IV
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CONTENTS
Acknowledgments ii
Abstract iii
Figures vi
Tables xvi
Abbreviations and Symbols xxvi
1. Introduction 1
2. Conclusions 3
3. Recommendations 6
4. Procedure and Analytical Research 7
5. Characteristics of Textile Processes and Pilot
Plant Operation 40
6. Filtration Process 62
7. Coagulation 119
8. Adsorption 179
9. Oxidation by Ozone 248
10. Ion Exchange 315
11. Hyperfiltration Process 415
12. Combined System and Comparison of Processes 431
References 437
Appendixes
A. Analytical Procedure for Selected Constituents 443
B. Method of Determining FINAD Index 445
C. Decree of the Ministry Council (Extract) 450
Glossary 455
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FIGURES
Number
Section 4
4-1 Dependence between the reduction of the extinction and
the wastewater dilution for various wavelengths 20
4-2 Change of transmission spectrum in the X value ranged
from 420 nm to 650 nm for Helasol Yellow GOK dye in
water solution before and after isolation of dye on
XAD-4 resin bed 21
4-3 Change of transmission spectrum in the \ value ranged
from 420 nm to 650 nm for Helasol Yellow GOK dye in
biologically treated wastewater before and after iso-
lation of dye on XAD-4 resin bed 22
4-4 Change of transmission spectrum in the A. value ranged
from 420 nm to 650 nm for wastewater of a character-
istic blue-green color before and after isolation of
color on XAD-4 resin bed 23
4-5 Change of transmission spectrum in the A. value ranged
from 420 nm to 650 nm for wastewater of a natural
yellow-green color concentrated before and after
isolation of color on XAD-4 resin bed . 24
4-6 Change of transmission spectrum in the A. value ranged
blue 420 nm to 650 nm for wastewater of a character-***
istic blue-green color concentrated before and after
isolation of color on XAD-4 resin bed 25
4-7 Separation of dyes on a chromatographic column. Mix-
ture of dyes separated from biologically treated
wastewater on XAD-4 resin bed 26
4-8 Separation of dyes on a chromatographic column. Mix-
ture of dyes separated from biologically treated
wastewater on XAD-4 resin bed 27
4-9 Separation of dyes on a chromatographic column. Mix-
ture of dyes separated from biologically treated
wastewater by extraction 28
VI
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Number Page
_-—,— a—
Section 5
5-1 Finishing plant A. Schematic plan of the bleach and
dye houses 44
5-2 Finishing plant B. Schematic plan of the bleach and
dye houses 45
5-3 Finishing plant A. PAD-STEAM dyeing machine processes .... 46
5-4 Finishing plant B. PAD-STEAM dyeing machine processes .... 47
5-5 Finishing plant A. Bleach house 48
5-6 Finishing plant B. Bleach house 49
5-7 Schematic plan of the primary treatment plant and the
pilot plant in Andrychow 51
5-8 Schematic diagram of the pilot plant filtration and
adsorption installation 52
5-9 Schematic diagram of the pilot coagulation instal-
lation 53
5-10 Schematic diagram of the pilot upflow filtration
installation 53
5-11 Schematic diagram of the pilot ion-exchange instal-
lation 53
5-12 Schematic diagram of the pilot ozone oxidation
installation 53
5-13 Schematic diagram of the pilot installation for
combined treatment processes 54
5-14 Hyperfiltration pilot plant diagram 55
5-15 Pilot plant time-phase diagram 56
Section 6
6-1 Experimental laboratory model for rapid filtration of
secondary effluent 77
6-2 Efficiency of contaminant removal from biologically
treated wastewater during the rapid filtration 78
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Number Page
6-3 Pressure versus depth in a gravity filter at various
times during a filter run. Single medium filter.
First stage of investigations, laboratory scale 79
6-4 Pressure versus depth in a gravity filter at various
times during a filter run. Dual media filter. First
stage of investigations, laboratory scale 80
6-5 Scheme of apparatus applied for pilot plant wastewater
filtration process . 81
6-6 Screening curve of dual media filtration. Grain size
distribution of a dual media filtration bed, col-
umns 8 and C, pilot scale 82
6-7 Statistical variations in suspended solids during
series I, pilot plant 83
6-8 Statistical variations in BOD during series I,
pilot plant 84
a
6-9 Statistical variations in suspended solids during
series II, pilot plant 85
6-10 Statistical variations in BOD during series II,
pilot plant 86
6-11 Statistical variations in suspended solids during
series III, pilot plant 87
6-12 Statistical variations in BOD during series III,
pilot plant 88
6-13 Pressure versus depth in a gravity filter at various
times during a filter run. Second stage of investi-
gation, pilot plant 89
6-14 Variability of suspended solids content, during the
time of the filtration cycle, in the influent and
effluent from individual columns 90
6-15 Suspended solids concentration in wastewater at vari-
ous depths of the filtration bed during the filter
run, pilot plant, series IV 91
6-16 Variability of suspended solids content during the
time of the filtration cycle in the influent and
effluent, series V, second stage of investigation 92
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Number Page
6-17 Suspended solids concentration in wastewater at vari-
ous depths of the filtration bed during the filter
run, pilot plant, series V 92
6-18 Course of the colored wastewater wave flow through
particular layers of the bed during the filtration
process, stage II, series V, measurement 1 93
6-19 Course of the colored wastewater wave flow through par-
ticular layers of the bed during the filtration
process, stage II, series V, measurement 2 94
Section 7
7-1 The relative value of color removal according to coag-
ulation time 139
7-2 Relation between color removal and coagulant dose for
three pH values of wastewater 140
7-3 Relation between color removal and coagulant dose for
three pH values of wastewater 141
7-4 Relation between color removal and the coagulant dose
for three pH values in wastewater initially oxidized
with a dose of 8 mg CK/l NaOCl 142
7-5 Relation between color removal and the coagulant dose
for three pH values in wastewater initially oxidized
with a dose of 8 mg CK/l NaOCl 143
7-6 Relation between color removal and the coagulant dose
for three pH values in wastewater initially oxidized
with a dose of 16 mg C12/1 NaOCl 144
7-7 Relation between color removal and coagulant dose for
three pH values in wastewater initially oxidized
with a dose of 16 mg C12/1 NaOCl 145
7-8 Relation between color removal and coagulant dose for
three pH values in wastewater initially oxidized
with a dose of 24 mg CK/l NaOCl 146
7-9 Relation between color removal and coagulant dose for
three pH values in wastewater initially oxidized
with a dose of 24 mg C12/1 NaOCl 147
7-10 Relation between color removal and dose of NaOCl for
three pH values of wastewater 148
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Number Page
7-11 Relation between color removal and coagulant dose of
NaOCl for three pH values of wastewater 149
7-12 Average color removal in relation to the coagulant
dose and pH value 150
7-13 Average color removal during the preliminary oxida-
tion with* NaOCl in relation to pH values 151
7-14 Relation between COD removal and coagulant dose for
three pH values in wastewater 152
7-15 Relation between COD removal and coagulant dose for
three pH values in wastewater 153
7-16 Relation between COD removal and coagulant dose for
three pH values in wastewater 154
7-17 Relation between COD removal and coagulant dose for
three pH values in wastewater 155
7-18 Average COD removal in relation to coagulant and
pH values 155
7-19 Influence of preliminary oxidation before coagula-
tion on COD removal 156
7-20 Relation between the nonionic detergent removal and
coagulant dose for three pH values in wastewater ...... 157
7-21 Relation between the nonionic detergent removal and
coagulant dose for three pH values in wastewater 158
7-22 Average removal of nonionic detergents in relation
to the coagulant dose and the pH values in wastewater .... 159
7-23 Influence of preliminary oxidation on nonionic deter-
gent removal in wastewater after coagulation 160
7-24 Influence of oxidation with NaOCl on removal of resid-
ual aluminum from coagulated wastewater 161
7-25 Relation between the removal of color measured spec-
trophotometrically at A. = 400 nra and the dose of
NaOCl added before coagulation with 200 mg
Al2/S04/3-18H20/l 162
7-26 Relation between the removal of color measured spec-
trophotometrically at A, = 550 nm and the dose of
NaOCl added before coagulation with 200 mg
Al2/S04/3-18H20/l 163
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Number Page
7-27 Upward flow filtration column used for contact
coagulation 164
7-28 Coagulation reactor with suspended floes 165
7-29 Flow time spectrum in filtration columns 166
Section 8
8-1 Determination of phenol number by the FINAD method 204
8-2 Determination of indole number by the FINAD method 204
8-3 Determination of detergent number by the FINAD method 205
8-4 Adsorptive capacity of activated carbons expressed by
the FINAD indexes 206
8-5 Influence of contact time on change of COD, detergent,
and color concentration in wastewater treated with
Z-4 and Calgon 207
8-6 Influence of Z-4 dose on percent removal of COD and
detergents (contact time = 0.5 h, pH = 7.8, room
temperature) 208
8-7 Influence of Z-4 and Calgon dose on percent removal
of COD, detergents, and color 209
8-8 Influence of Z-4, Calgon, and Hydrodarco dose on per-
cent removal of detergents and color (contact
time = 1 h, ph = 8.5, room temperature) 210
8-9 Adsorption isotherms for COD (contact time = 1 h,
pH = 8.5, wastewater after biological treatment,
room temperature) 211
8-10 Adsorption isotherms for COD (contact time = 1 h,
pH = 7.7, coagulated wastewater, room temperature) 211
8-11 Adsorption isotherms for TOC (contact time = 1 h,
pH = 8.5, wastewater after biological treatment,
room temperature) 212
8-12 Scheme of a laboratory installation model for adsorp-
tion on activated carbon beds 213
8-13 Course of COD removal on continuous adsorption process
expressed as the average values of every 10 series,
laboratory scale 214
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Number page
8-14 Course of BOD removal on continuous adsorption process
expressed as the average.values of every 10 series,
laboratory, scale 215
8-15 Course of color removal on continuous adsorption process
expressed as the average values of every 10 series,
laboratory scale 216
8-16 Course of detergent removal on continuous adsorption
process expressed as the average values of every
10 series, laboratory scale 217
8-17 Residual COD concentrations according to carbon type
and height of adsorptive column filling, laboratory
scale 218
8-18 Residual BOD concentrations according to carbon type
and height of adsorptive column filling, laboratory
scale 219
8-19 Residual color concentrations according to carbon type
and height of adsorptive column filling, laboratory
scale 220
8-20 Residual detergent concentrations according to carbon
type and height of adsorptive column filling, labo-
ratory scale 221
8-21 Relation of COD adsorption rate to concentration in
inflow, continuous process, laboratory scale 222
8-22 Relation of color adsorption rate to concentration in
inflow, continuous process, laboratory scale 223
8-23 Scheme of installation for studies of adsorption in
a continuous system, pilot scale 224
8-24 COD removal in continuous two stages of adsorption,
series III 225
8-25 BOD removal in continuous two stages of adsorption,
series III 226
8-26 Color removal in continuous two stages of adsorption,
series III 227
8-27 Detergent removal in continuous two stages of adsorption,
series III 228
8-28 COD removal in continuous three stages of adsorption,
series IV 229
xii
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Number Page
8-29 BOD removal in continuous three stages of adsorption,
series IV 230
8-30 Color removal in continuous three stages of adsorption,
series IV 231
8-31 Detergent removal in continuous three stages of adsorp-
tion, series IV 232
8-32 Relation of rate of color and COD adsorption to con-
centration in inflow, continuous process on Z-4,
series IV, pilot scale 233
8-33 COD removal in continuous adsorption on Z-4 carbon of
various granulation, series V 234
8-34 BOD removal in continuous adsorption on Z-4 carbon of
various granulation, series V 235
8-35 Color removal in continuous adsorption on Z-4 carbon
of various granulation, series V 236
8-36 Course of COD removal from coagulated wastewater,
pilot scale 237
8-37 Course of color removal from coagulated wastewater,
pilot scale 238
Section 9
9-1 Scheme of ozonation apparatus on a laboratory scale,
batch system 266
9-2 Change of absorption spectrum within the A, value.
Range from 400 nm to 650 nm for the Salt of Naph-
thanil Blue BT dye in tap water solution in the
course of ozone oxidation process. Ozone concen-
tration in air = 12.7 mg/1, air flow = 18.6 1/h 267
9-3 Change of absorption spectrum within the X value. Range
from 400 nm to 650 nm for helanthrene green BS dye in
tap water solution in the course of ozone oxidation
process. Ozone concentration in air = 12.7 mg/1,
air flow = 13.5 1/h 267
9-4 Dominant color removal depending on contact time of
ozone oxidation for particular dyes in tap water
solution 268
xn i
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Number page
9-5 Dominant color removal depending on contact time of
ozone oxidation for particular dyes in biologically
treated wastewater 269
9-6 Dominant color removal depending on contact time of
ozone oxidation for five combinations of dyes in
biologically treated wastewater 270
9-7 Dominant color removal depending on dye concentra-
tion for particular dyes in biologically treated
wastewater . 271
9-8 Amount of ozone consumed by sample depending on dye
concentration for particular dyes in biologically
treated wastewater 271
9-9 Relation between TOC and COD in ozone-treated waste-
water with particular dyes added 272
9-10 Schematic flow diagram of cocurrent ozonation on a
laboratory scale 273
9-11 Schematic flow diagram of one-stage countercurrent
ozonation on a pilot scale 274
9-12 Removal of contaminants in a one-stage continuous
countercurrent column using 10, 30, 50, and 70 mg/1
ozone doses 275
9-13 Schematic flow diagram of double-stage ozonation on
a pilot scale 276
9-14 Removal of contaminants in double-stage continuous
columns using 10, 30, 50, and 70 mg/1 ozone doses 277
Section 10
10-1 Scheme of ion-exchange system 327
10-2 Changes of anionic resin (Amberlite IRA-401) capacity
in successive series 328
10-3 Percent color removal versus bed loading (BV/h) 329
10-4 Percent COD removal versus bed loading (BV/h) 330
10-5 Percent anionic detergent removal versus bed
loading (BV/h) 331
10-6 Percent nonionic detergent removal versus bed
loading (BV/h) 332
xiv
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Number
Section 11
11-1 Schematic diagram of pilot plant at Andrychow for
investigation of hyperfiltration process 419
11-2 Operating performance of cellulose acetate spiral
wound membrane, model ROGA 4160 S 420
11-3 Color analyses of the first day sample 421
11-4 Color analyses of the second day sample 422
11-5 Color analyses of the third day sample 423
11-6 Color analyses of the fourth day sample 424
xv
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TABLES
Number Page
Section 4
4-1 Values of relative extinction at 450 nro and 500 nm
for 10 wastewater samples treated biologically 29
4-2 Values of relative extinction at 450 nm and 500 nm
for 10 wastewater samples treated by coagulation 30
4-3 Dye recovery on column with resin XAD-4 and percent-
age of dye retention on chromatographic column 31
4-4 Dye recovery on column with resin XAD-4 and percent-
age of dye retention on chromatographic column 34
4-5 Removal of dyes from wastewater by extraction 35
4-6 Eluting solvents for various groups of dyes 36
4-7 Column chromatography for dye mixtures in water and
wastewater solution 37
4-8 Column chromatography for dye mixtures in Table 4-4 .... 38
4-9 Column chromatography for dye mixtures from dye-
house 38
4-10 Percent dye recovery from wastewater colored with
various dye mixtures . ." 39
4-11 Percent recovery from dyes isolated by extraction 39
Section 5
5-7 Consumption of dyes, chemicals, and auxiliary agents
in the Andrychow cotton plant in 1976 57
5-2 Activated sludge process, pilot plant, first period .... 59
5-3 Influent and effluent wastewater quality at Andrychow
mechanical-biological treatment plant. Studies
carried out after October 10, 1975 60
xvi
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Number Page
Section 6
6-1 Characteristics of filtration beds applied to inves-
tigations on laboratory scale, stage I 95
6-2 Effectiveness of the laboratory scale filtration proc-
ess performed in the first stage of investigations .... 96
6-3 Characteristics of the filtration beds used for pilot
plant investigations, stage II 100
6-4 Filtration bed values for column B 101
6-5 Effects of contaminant removal during filtration in
pilot scale investigations, series I, stage II 102
6-6 Effects of contaminant removal during filtration in
pilot scale investigations, series II, stage II 105
6-7 Effectiveness of the pilot plant filtration process
performed in series III, stage II 107
6-8 Effectiveness of pilot scale filtration process based
on average samples performed in series IV, stage II ... 114
6-9 Results of physicochemical analysis in series V,
stage II 117
6-10 Washing conditions of operation of a dual media fil-
tration bed in relation to the cycle of filtration.
Granulation of the bed according to the curve in
figure 6-7, column B, series V, pilot scale 118
Section 7
7-1 Percent content of particular dye groups in total
consumption of dyes in 1975 167
7-2 Color removal with 8 mg C12/1 167
7-3 Residual dissolved aluminum after coagulation process . . . 168
7-4 Contaminant removal during filtration with simul-
taneous coagulation for higher pH (average results
based on 16 days of operation) 169
7-5 Contaminant removal during filtration with simul-
taneous coagulation for lower pH (average results
based on 24 days of operation) 170
xvn
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Number Paae
———— - 3
7-6 Contaminant removal during filtration with simul-
taneous coagulation applied to wastewater prelim-
inarily oxidized with NaOCl (average results based
on 10 days of operation) 171
7-7 Contaminant removal during filtration with simul-
taneous coagulation applied to wastewater prelim-
inarily oxidized with NaOCl (average results based
on 28 days of operation) 172
7-8 Contaminant removal during filtration with simul-
taneous coagulation applied to wastewater prelim-
inarily oxidized with NaOCl (average results based
on 36 days of operation) 173
7-9 Contaminant removal during filtration with simul-
taneous coagulation applied to wastewater prelim-
inarily oxidized with NaOCl (average results based
on 18 days of operation) 174
7-10 Contaminant removal during filtration with simul-
taneous coagulation applied to wastewater prelim-
inarily oxidized with NaOCl (average results based
on 14 days of operation) 175
7-11 Contaminant removal during filtration with simul-
taneous coagulation followed by oxidation with
NaOCl and subsequent filtering (average results
based on 14 days of operation) 176
7-12 Contaminant removal during coagulation in suspended
floes reactor followed by filtration (average results
based on 26 days of operation) 177
7-13 Contaminant removal during coagulation in suspended
floes reactor followed by filtration (average results
based on 10 days of operation) 178
Section 8
8-1 Physicochemical parameters of activated carbons 239
8-2 Results of studies of porous microstructure of acti-
vated carbons 240
8-3 Comparison of adsorption effects using three kinds of
activated carbon, laboratory scale investigations .... 240
8-4 Physicochemical properties of activated carbons used
in the regeneration process and of fresh carbons 241
xvm
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Number Page
8-5 Results of regeneration of Z-4, Calgon, and ARZ used
in laboratory investigations by a continuous method . . . 242
8-6 Results of regeneration of Carbopol Z-4, spent in the
two-stage adsorption process (AD1 and AD0) 243
1 £.
8-7 Conditions of operation for activated carbon columns,
pilot scale installation 244
8-8 Loads removed and final pollutant concentrations in
individual series of adsorption on activated carbon,
pilot scale installation 245
8-9 Characteristics of carbon beds and conditions of opera-
tion used for pilot scale adsorption of coagulated
wastewater 246
8-10 Average removal of particular pollutants on activated
carbon from coagulated wastewater at pilot plant 247
Section 9
9-1 COD determinations of dyes added to water and waste-
water in laboratory investigations 278
9-2 Single dyes used in ozone oxidation investigations .... 279
9-3 Technical parameters and ozone balance in the ozone
oxidation process of water dye solutions 280
9-4 Effectiveness of ozone oxidation of water dye solutions . . 283
9-5 Dyes fed into biologically treated wastewater 287
9-6 Effectiveness of ozone oxidation of biologically
treated wastewaters with the addition of indi-
vidual dyes and dye mixtures 288
9-7 Technical parameters and ozone balance in the ozone
oxidation process applied to biologically treated
wastewaters with the addition of individual dyes
and dye mixtures 296
9-8 Technical parameters and ozone balance in the oxida-
tion process applied to biologically treated waste-
waters with the addition of individual dyes of
different concentrations 299
9-9 Effectiveness of ozone oxidation of biologically
treated wastewater with the addition of individual
dyes of different concentrations 300
xix
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Number
9-10 Continuous cocurrent ozonation on a laboratory scale
of biologically treated and filtered wastewater—ozone
balance and contaminant removal 301
9-11 One-stage continuous countercurrent ozonation of bio-
logically treated and filtered wastewater—ozone
balance and color removal 305
9-12 One-stage continuous countercurrent ozonation of bio-
logically treated and filtered wastewater—BOD,.,
COD, and detergent removal b 307
9-13 Double-stage continuous ozonation of biologically
treated and filtered wastewatei—ozone balance
and color removal 310
9-14 Double-stage continuous ozonation of biologically
treated and filtered wastewater—BODj-, COD, and
detergent removal . b 311
9-15 Comparative table of average values of percentage
contaminant removal obtained by single-stage and
double-stage ozonation 312
9-16 One-stage continuous ozonation of biologically treated
wastewater after coagulation, filtration, and carbon
adsorption processes—ozone balance and color removal . . 313
9-17 One-stage continuous ozonation of biologically treated
wastewater after coagulation, filtration, and carbon
adsorption processes—BOD., COD, TOC, and detergent
removal 314
Section 10
10-1 Seven anionic and five cationic resins used in labo-
ratory screening studies 333
10-2 Properties of different resins used in laboratory
experiments 334
10-3 Dye-exchange capacity of resins used in laboratory
experiments with reference to the best-absorbed dye ... 335
10-4 Decrease in dye capacity after successive regen-
eration 336
10-5 Results of exchange capacity for wastewater inves-
t i gat ions 337
xx
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Number page
10-6 Characteristics of wastewater fed to the double
ion-exchange system 338
10-7 Regenerator requirements for resins 339
10-8 The effectiveness of the single ion-exchange process
with cationic and anionic resins (Amberlite IRA-401)
at a bed loading of 6 BV/h (1 series) 340
10-9 The effectivness of the single ion-exchange process
with cationic and anionic resins (Amberlite IRA-401)
at a bed loading of 6 BV/h (2 series) 341
10-10 The effectiveness of the single ion-exchange process
with cationic and anionic resins (Amberlite IRA-401)
at a bed loading of 6 BV/h (3 series) 342
10-11 Investigations on Zeolite 325 (cation) and Amberlite
IRA-401 (anion) at a bed loading of 6 BV/h 343
10-12 Investigations on Zeolite 325 (cation) and Amberlite
IRA-401 (anion) at a bed loading of 12 BV/h 343
10-13 Investigations on Zeolite 325 (cation) and Amberlite
IRA-401 (anion) at a bed loading of 18 BV/h 343
70-14 Investigations on Zeolite 325 (cation) and Zeolite
KMP (anion) at a bed loading of 6 BV/h 344
10-15 Investigations on Zeolite 325 (cation) and Zeolite
KMP (anion) at a bed loading of 12 BV/h 344
10-16 Investigations on Zeolite 325 (cation) and Zeolite
KMP (anion) at a bed loading of 18 BV/h 344
10-17 Percentage color removal from biologically treated
wastewater with dyes of 50 mg/1 concentration added,
for different anionic exchange resins 345
10-18 Percentage of color removal from biologically treated
wastewater with dyes of 60 mg/1 concentration added,
for different cationic exchange resins 346
10-19 Percentage of color removal from biologically treated
wastewater without dyes added 347
10-20 Average percentage of COD removal in the ion-exchange
process 348
10-21 Average percentage of anionic detergent removal in the
ion-exchange process 349
xxi
-------
Number
10-22 Average percentages of pollutant removal obtained in
the ion-exchange process 350
10-23 The effectiveness of the dual ion-exchange process
with cationic and anionic resins (Zeolite 325 and
Amberlite IRA-401) at a bed loading of 6 BV/h
(4 series) 351
10-24 The effectivess of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Amberlite
IRA-401) at a bed loading of 6 BV/h (5 series) ...... 354
10-25 The effectiveness of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Amberlite
IRA-401) at a bed loading of 6 BV/h (6 series) 356
10-26 The effectiveness of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Amberlite
IRA-401) at a bed loading of 6 BV/h (7 series) 359
10-27 The effectiveness of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Amberlite
IRA-401) at a bed loading of 6 BV/h (8 series) 362
10-28 The effectiveness of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Amberlite
IRA-401) at a bed loading 12 BV/h (9 series) . - 364
10-29 The effectiveness of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Amberlite
IRA-401) at a bed loading 12 BV/h (10 series) 367
10-30 The effectiveness of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Amberlite
IRA-401) at a bed loading 12 BV/h (11 series) ...... 370
10-31 The effectivenss of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Amberlite
IRA-401) at a bed loading 12 BV/h (12 series) 373
10-32 The effectiveness of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Amberlite
IRA-401) at a bed loading of 12 BV/h (13 series) 375
10-33 The effectiveness of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Amberlite
IRA-401) at a bed loading of 18 BV/h (14 series) 377
10-34 The effectiveness of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Amber-
lite IRA-401) at a bed loading of 18 BV/h (15 series) . - 380
xx ii
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Number Page
10-35 The effectiveness of the dual ion-exchange process
with cationic and anionic resins (Zeolite 325 and
Amberlite IRA-401) at a bed loading of 18 BV/h
(16 series) 383
10-36 The effectiveness of the dual ion-exchange process
with cationic and anionic resins (Zeolite 325 and
Zeolite KMP) at a bed loading of 6 BV/h (17 series) ... 385
10-37 The effectiveness of the dual ion-exchange process
with cationic and anionic resins (Zeolite 325 and
Zeolite KMP) at a bed loading of 6 BV/h (18 series) ... 387
10-38 The effectiveness of the dual ion-exchange process
with cationic and anionic resins (Zeolite 325 and
Zeolite KMP) at a bed loading of 6 BV/h (19 series) ... 389
10-39 The effectiveness of the dual ion-exchange process
with cationic and anionic resins (Zeolite 325 and
Zeolite KMP) at a bed loading of 12 BV/h (20 series) ... 391
10-40 The effectiveness of the dual ion-exchange process
with cationic and anionic resins (Zeolite 325 and
Zeolite KMP) at a bed loading of 12 BV/h (21 series) ... 394
10-41 The effectivness of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Zeolite
KMP) at a bed loading of 12 BV/h (22 series) 397
10-42 The effectiveness of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Zeolite KMP)
at a bed loading of 18 BV/h (23 series) 400
10-43 The effectiveness of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Zeolite
KMP) at a bed loading of 18 BV/h (24 series) 403
10-44 The effectiveness of the dual ion-exchange process with
cationic and anionic resins (Zeolite 325 and Zeolite
KMP) at a bed loading of 18 BV/h (25 series) 406
10-45 Average contaminant removal values in the dual ion-
exchange process with cationic and anionic resins
(Zeolite 325 and Amberlite IRA-401), at a bed loading
of 6 BV/h during five successive series 408
10-46 Average contaminant removal values in the dual ion-
exchange process with cationic and anionic resins
(Zeolite 325 and Amberlite IRA-401), at a bed loading
of 12 BV/h during five successive series . 409
xxm
-------
Number Page
10-47 Average contaminant removal values in the dual ion-
exchange process with cationic and anionic resins
(Zeolite 325 and Amberlite IRA-401), at a bed loading
of 18 BV/h during three successive series 410
10-48 Average contaminant removal values in the dual ion-
exchange process with cationic and anionic resins
(Zeolite 325 and Zeolite KMP), at a bed loading of
6 BV/h during three successive series .... 411
10-49 Average contaminant removal values in the dual ion-
exchange process with cationic and anionic resins
(Zeolite 325 and Zeolite KMP), at a bed loading of
12 BV/h during three successive series .... 412
10-50 Average contaminant removal values in the dual ion-
exchange process with cationic and anionic resins
(Zeolite 325 and Zeolite KMP), at a bed loading of
18 BV/h during three successive series 413
10-51 Average values of pollutant removal for cation Zeolite
325 and anion Amberlite IRA-401 dual systems 414
10-52 Average values of pollutant removal for the cation
Zeolite 325 and the anion Zeolite KMP system 414
Section 11
11-1 Preliminary test for ROGA membrane using 0.1 mol
salt solution . " . 425
11-2 Preliminary test for dynamically formed membrane
using 0.1 mol salt solution 426
11-3 Operating conditions of the spiral wound cellulose
acetate module (model ROGA 4160 S) during the
wastewater test 427
11-4 Chemical analysis of the composite samples for entire
test period 430
Section 12
***"
12-1 Average effectiveness of the combined system for COD .... 433
12-2 Average effectiveness of the combined system for
nonionic detergents 433
12-3 Effectiveness of individual processes applied after
biological treatment 434
xxiv
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Number Page
12-4 Consumption of chemicals and materials and consump-
tion volume of water wasted 435
12-5 Energy consumption and wastewater pumping head 436
xxv
-------
ABBREVIATIONS AND SYMBOLS
ACP --Andrychow Cotton Plant
ADX —Carbon used in first stage of adsorption
AD2 --Carbon used in second stage of adsorption
BOD5 —Five-day biological oxygen demand
CC —Column chromatography
CEBEA —Chemical Industry Research and Development Center (Poland)
COD —Chemical oxygen demand
Co-Pt scale —Cobalt-platinum scale
EPA —Environmental Protection Agency (United States)
IGW —Water Economy Research Institute (Poland)
IMWM --Institute of Meteorology and Water Management (Poland)
LM —Methylene number
MG —Milligram number
Pt scale —Platinum scale for color
TLC —Thin-layer chromatography
TOC —Total organic content
xxvi
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SECTION 1
INTRODUCTION
Work on project PR-5-532-3 began in 1972 in the then Water Economy
Research Institute (IGW), Warsaw, Poland, in its Cracow Water Protection
Section. The agreement between IGW and the U.S. Environmental Protection
Agency was signed originally for the 3-year period from June 30, 1972, to
June 29, 1975. The aim of the research was to determine the effectiveness
and suitability of selected physicochemical technological processes for the
thorough removal of color, detergents, and other refractory pollutants from
textile wastewater, and to determine the most effective and economically
feasible technological processes of tertiary treatment of combined textile
and municipal wastewater, after conventional mechanical-biological treat-
ment, for removing refractory substances and for bringing the wastewater
quality up to a very high level.
Highly effective treatment of wastewater from the textile industry,
whichjs one of the largest sources of strongly polluted wastewater, is
becoming one of the most important requirements in small-stream catchment
areas and, in particular, in areas deficient in water resources. Wastewater
from the textile industry contains considerable amounts of substances that
are wholly or partly resistant to treatment by biological means. As a
result, textile industry wastewater that has been treated conventionally in
a mechanical-biological plant cannot be put directly back into production,
and if it is discharged into surface waters out of necessity, it causes
deterioration of the qualitative indicators of the water. This deteriora-
tion stems especially from such refractory substances as dyes, detergents,
and other synthetic compounds used in the textile industry. These consti-
tute a special problem when the receiving stream is small and high water
quality must be maintained because the watercourse or stream is used as a
supply source for domestic purposes. The further expansion of the textile
industry will make the situation in water administration worse; therefore,
it is necessary to study more effective methods of tertiary treatment of
textile wastewater now.
This study set out to check the effectiveness of technological proc-
esses of third-stage treatment for removal of refractory substances, in
particular, color, COD, and detergents. The investigations were planned
first on a laboratory scale, and then on a large laboratory scale at the
pilot plant in Andrychow. Studies were made of a series of physicochemical
processes applied to wastewater after mechanical-biological treatment.
These studies included:
-------
Rapid filtration on single and multi-media beds,
adsorption on granular activated carbon,
ion exchange on anionic and cationic resins,
coagulation with the use of typical coagulants and with the
application of auxiliary chemicals,
oxidation with ozone and chloride, and
reverse osmosis.
The research program was designed to examine these processes both individ-
ually and in combination in a linked technological system.
The research work began with investigations on a laboratory scale. At
the same time, the construction of a pilot plant was begun at the municipal-
industrial sewage treatment plant at Andrychow. As a result of delays in
the construction and completion of the pilot plant equipment, and in par-
ticular, on account of difficulties in purchasing equipment for reverse
osmosis, the project completion date was postponed for another 2 years to
June 29, 1977. Meanwhile, as a result of reorganization in 1973, the Water
Protection Section in Cracow was transferred to the new Institute of
Meteorology and Water Management, which administered the project until its
completion.
-------
SECTION 2
CONCLUSIONS
1. The concept of applying biological treatment before physicochemical
tertiary treatment has proved valid for mixed textile and municipal
wastewater in a proportion varying from 1:1 to 2:1. Activated sludge
that decomposes a considerable load of organic pollutants relieves the
physicochemical processes and to a large degree levels out the flow
variation and variable composition of the wastewater. As a result,
smaller quantities of chemicals are needed for coagulation and oxi-
dation, and less activated carbon is consumed in the adsorption proc-
ess, making the operation of the physicochemical processes more certain
and their control easier. Activated sludge also increases the effec-
tiveness of organic load removal for the whole treatment system.
2. The optimum system of tertiary treatment that brings the quality of the
treated wastewater up to class I water purity (appendix C) and allows
for possible reclamation of water for the supply of different utilities
is as follows:
Contact coagulation with aluminum sulphate on upstream fil-
ters possibly preceded by chlorination,
filtration on a two-layer anthracite-sand bed, and
adsorption on activated carbon.
3. The investigations show that, where very effective biological treatment
of wastewater is needed, rapid sand filtration can be recommended as
either a final or an intermediate process applied before other tertiary
physicochemical processes such as adsorption, ion exchange, or hyper-
filtration. The filtration itself reduces the concentration of sus-
pended solids to below 10 mg/1, which results in 30 to 75 percent
removal of BODS load.
4. A dual media bed is more effective for filtration of biologically
treated wastewater than a single medium bed. A dual media bed ensures
better elimination of suspended solids and a filtration cycle of 23 to
36 h, in contrast to the 3.5 to 23.5-h filtration cycle obtained with a
single medium bed.
5. The increase of the filtration rate up to 15 m3/m2h diminishes the
effectiveness of the bed because the removal of contaminants becomes
less regular, especially in the case of beds having very finely granu-
-------
lated filtration media. A filtration rate of 8 m3/m2h has been found
to be the optimum for the Andrychow municipal-textile wastewater.
6. The method of contact coagulation with simultaneous upflow filtration
lends itself more to the coagulation of biologically treated wastewater
than does the conventional coagulation performed in a reactor with
suspended floes. Before the coagulation process, preliminary treatment
is necessary for pH control and efficient removal of organics in the
activated sludge process to prevent secondary pollution of the waste-
water by aluminum compounds developing in the solution.
7. Adsorption on activated carbon ensures removal of a broad range of
refractory pollutants from biologically treated, mixed textile industry
and municipal wastewater. The effectiveness of treatment depends on
the appropriate choice of activated carbon and process parameters.
Activated carbons with large pore volumes should be used for treating
wastewater with a high concentration of pollutants. Such a carbon is
Carbopol Z-4. But where thorough removal of pollutants is necessary,
carbons with a large adsorptive surface having many tiny pores
o
(<1,500 A) should be chosen. Among such carbons are Hydrodarco and
Calgon.
8. Adsorption on activated carbon applied to wastewater after biological
treatment and coagulation will remove approximately twice the percent
of specific refractory pollutants compared to removal from biologically
treated, noncoagulated wastewater. Percentage removal of typical
parameters was: COD and color—more than 80 percent; TOC--65 percent
on the average. The combination of adsorption with coagulation is the
best method of practical application.
9. Ozone oxidation of previously biologically treated wastewater is an
effective process, especially for color removal, which approaches 67
percent, and for removal of anionic detergents, which approaches 100
percent. Removal of organic compounds designated as COO occurs slowly
(32 percent removal) and with a large ozone demand represented by a
dose of 50 mg/1 witti a 30-min contact time. The application of ozone
oxidation during the last stage of the combined tertiary treatment
system after adsorption proved to have little effect.
10. The ion-exchange process is effective for removing color and anionic
detergents. However, the disadvantages of this process—a short work
cycle (6 to 20 h), a long regeneration ^ime, a large amount of post
regeneration waters with a large pollut^t load, and the cost of
resins—render it unsuitable for use wit^nrixed municipal and textile
wastewater.
11. The research on the hyperfiltration process should be treated as pre-
liminary and as a guide. It was carried out mainly in order to compare
its effects with those of other tertiary treatment processes. The
effectiveness of hyperfiltration in the reduction of color and dis-
-------
solved substances is satisfactory. There remains, however, the un-
solved problem of the concentrate, which in the case of mixed textile
and municipal wastewater requires additional treatment. The applica-
tion of this process to isolated textile wastewater from the dyeing and
cloth-finishing processes is promising because of opportunity utiliza-
tion of both product water and concentrate.
12. As has been shown in the hyperfiltration tests so far, thorough pre-
liminary removal of fine suspended solids and colloids from wastewater
is of essential significance to prevent floes decline, fouling, and
module damage due to clogging. This is particularly important when
spiral wound membranes are applied to biologically treated mixed waste-
water.
13. The application of thin-layer and column chromatography for analysis of
color substances in biologically treated combined municipal and textile
wastewater appeared not to be useful because the concentration of dyes
was too low to yield a clear chromatogram. However, the above-mentioned
methods, particularly the column chromatography combined with prelimi-
nary separation of dyes on XAD-4 resin, can be useful for the quanti-
tative analysis of dyes in concentrated wastewater from a dyeing house.
-------
SECTION 3
RECOMMENDATIONS
Research should be continued on the process of hyperfiltration (reverse
osmosis) of isolated textile wastewater from the dyeing and cloth-finishing
processes.
In the light of research already completed, the application of hyper-
filtration to the treatment of mixed textile and municipal wastewater is at
present technically and economically unsound, mainly because there is no way
to make use of the concentrate. It would be appropriate to undertake re-
search to determine the technological properties and optimum technology for
the treatment and possible utilization of sludge and concentrates produced
in the individual physicochemical processes studied.
Processes for treating sediments and byproducts have a large, and in
some cases, a deciding influence on the costs of tertiary treatment proc-
esses.
For purposes of reclaiming treated combined textile and municipal
wastewater for supply to different utilities, bacteriological composition is
very important. Further research on what has been determined to be the
optimum tertiary treatment system (coagulation, filtration, and adsorption)
should take into account the removal of bacterial pollutants.
It is also advisable to examine in more detail the influence of the
method and degree of biological treatment on the parameters and economics of
tertiary treatment of mixed textile and municipal wastewater.
There is a need for further pilot investigations into oxidation, using
both chlorine and oxygen from air with the help of different catalysts such
as ultraviolet light.
-------
SECTION 4
PROCEDURE AND ANALYTICAL RESEARCH
ANALYTICAL PROCEDURE
Daily composite samples of the wastewater from each particular unit
process were collected from influent and effluent for analysis. When a
continuous process was involved, average samples were collected propor-
tionally to flow during a day or cycle of operation. In addition, grab
samples were taken occasionally in order to study the course of the process
during a cycle of operation.
The basic analytical determination applied in each process comprised
the following indicators:
pH reaction—according to the standard methods [1];
alkalinity—according to the standard methods;
acidity—according to the standard methods;
suspended solids—according to the standard methods [1,2];
permanganate COD--according to the procedure described in appen-
dix A [2];
dichromate COD—according to the standard methods ['!];
BOD5—by standard dilution technique [1];
anionic detergents (ABS)—with the methylene blue method [1,2];
nonionic detergents—according to the procedure described in
appendix A;
color—by three methods:
1. spectrophotometrically, by light absorption measurement
within the range of wavelengths 360 to 650 nm (the average
absorption value has been calculated from 10 measurements on
the absorption curve divided into 10 equal sections);
2. color threshold; and
3. color related to Pt scale.
In the investigations of individual processes some other analytical
determinations have been made:
Aluminum content—according to the procedure described in appen-
dix A;
conductivity—with conductivity meter;
ozone—by iodometric method [1];
turbidity—according to the standard procedure [2]; and
-------
total organic carbon—with Beckman apparatus.
In the above-listed analysis, special attention has been given to the
color measurements and separation. The following subsections deal with this
problem.
TEST INVESTIGATIONS ON THE SPECTROPHOTOMETRIC DETERMINATION OF COLOR
Colored substances from the Andrychow Cotton Plant (ACP) are among the
main pollutants of the wastewater under investigation. Therefore, a quick
and reproducible method of determining color is necessary to make it pos-
sible to determine changes in the colored substance content of wastewater
subjected to different treatment processes.
The Lambert-Beer law defines the basic dependence between the absorp-
tion of light and the concentration of colored substances in the solutions
by the equation:
A = ECl
where:
A = extinction,•
E = absorption coefficient,
C = concentration of substance absorbing the light, and
1 = thickness of the fluid layer.
For solutions that, like the wastewater under investigation, contain more
than one dissolved substance:
A = £ A. = I x E. x C. .
1, 1 T,
Assuming that the average absorption coefficient appears in wastewater,
extinction is proportional to the concentration of colored substances in the
solution. The absorption spectra are described by similarly shaped curves
moved with regard to the axis on which the extinction values are plotted.
On the basis of this calculation, the rate of decrease of extinction which
can be measured for one wavelength, or as an average value for several
wavelenghts, is directly proportional to the concentration of dyes.
Tests to establish the accuracy of determining color in Andrychow
wastewater by spectrophotometrical measurement were carried out on 10 sam-
ples of wastewater after biological treatment and on 10 samples after coag-
ulation. Spekol and Specord spectrophotometers produced by Carl Zeiss Jena
were used for spectral analysis. Cuvettes 5 cm long were used. The anal-
ysis showed relatively large extinction values in the range from 400 to
500 nm; these were accepted as authoritative for further investigations. At
wavelengths greater than 500 nm the extinctions were small (below 0.05), and
8
-------
within the error range of the apparatus. The spectrum of the studied sam-
ples of wastewater was a continuous function. If the shapes of the curves
illustrating the dependence of extinction on the wavelength are identical
for the different samples, then the ratio of extinction values for two
arbitrarily chosen wavelengths on the curves in question should be constant.
Some calculations were performed as examples by taking extinction for
400 nm as equal to 1: for A = 450 nm, the extinction value = A* • and for
A = 500 nm, the extinction value -A". Thus, relative extinction can be
expressed as:
A ' A"
Y - _ an^ Y -
Xl ~ A and X2 - A
The results for 10 wastewater samples after biological treatment and
coagulation are presented in tables 4-1 and 4-2.
The results obtained were evaluated statistically as follows:
Wastewater samples after biological treatment:
10
For 450 nm: tj- ^ - 5.02
mean value of X3 X =0.50
ZU.-Y)2 = 0.0374 .
1r
Standard deviation (5) of a single result is:
= 0.064.
Dispersion of the results characterized by the coefficient of variance
(F) is:
T/ S x 100 0,064 x IQO
v = ~= = —o^o = 12M *
A.
For 500 nm: 10 _
E X. = 3.76; X = 0.38
EU.-JO2 = 0.0267
v _ 0.054 x 100
v ~ —
-------
Wastewater Samples After Coagulation:
For 450 nm: 10 _
E X. = 4.99; X = 0.50
.-Z) = 0.0421
Is
1.0421
= 0.068 x
0.50 '"
For 500 nm: 10
I X. = 3.61; X = 0.36
1=1 * '
SU'.-J)2 = 0.0249
S = ^-—-" = 0.052
= 0.052 x lop
0.36
The results show that the curves of dependence of extinction on wave-
length for biologically treated and coagulated wastewater have similar
shapes. However, the dispersion of results is considerable—from 12 to 14.5
percent. In connection with the above, the possibility of determining color
by summary extinction for the wavelengths 400, 450, and 500 nm is calcu-
lated: for A. = 400 nm, A was determined = 1; for A = 450 nm, A- was deter-
mined = X^i; and for X = 500 nm, A2 was determined = J.2; taking the
quotients: ^
10
-------
For the previously analyzed values contained in tables 4-1 and 4-2, it
was calculated that:
For biologically-treated wastewater:
10
I X. = 18.78; X = 1.88
1=1 *-
10 _
E(J.-^f)2 = 0.0806
S =K"'"g " = 0.095
0.095 x 100 =
1.88
For coagulated wastewater:
10 _
I X. = 18.60; X = 1.86
10 _
l(X.-XYz = 0.0978
1=1 ^
B - , 0.104
y 18
0.104 x 100
V = = 5.6% .
1.86
From the above calculation it is clear that, through the determination of
summary extinction, lesser coefficients of variations amounting to about 5
percent are obtained. Therefore, it is valid to accept values of summary
extinction or the average extinction of the chosen wavelength range of the
spectrum for comparison of wastewater color.
To check whether the decrease in concentration of colored substances
follows the Lambert-Beer law, an experiment was carried out in which a
sample of wastewater was diluted with distilled water in the ratios of 1:3,
1:1, and 3:1.
In the diluted samples extinction was determined for three wavelengths.
Taking the initial extinction value as equal to "I, relative extinction was
calculated respectively for individual dilutions and wavelengths. The
results are plotted in figure 4-1. From these it is clear that the depend-
ence between extinction and dilution is a straight line. So reduction of
11
-------
extinction is directly proportional to a decrease in the amount of color
substances in the wastewater.
ATTEMPTS AT CHROMATOGRAPHIC IDENTIFICATION OF DYE SUBSTANCES
Subject and Scope of Investigations
On account of the significance dye substances and the color they pro-
duce have in textile wastewater, it was necessary to carry out additional
investigations to assess the possibilities of more precisely identifying
those dye substances and of determining the effectiveness of wastewater
treatment processes. For this purpose, methods of column chromatography
(CC) and thin-layer chromatography (TLC) were used. These methods are used
in many fields of chemical technology to separate and treat substances, to
isolate them for solutions or mixtures, and to make qualitative and quanti-
tative determinations of dyes. The investigations were carried out by
choosing the chromatographic system which would best allow for separation
and identification of dye compounds at different concentrations in textile
wastewater. The work was begun with a chromatographic analysis conducted on
thin-layer plates covered with silica gel, cellulose, or aluminum oxide.
Then the column chromatography method was applied and performed in parallel
with the thin-layer method.
The following dye samples were used for chromatographic analyses:
Dyes in pure water solutions—0.5%,
dyes added to biologically treated wastewater,
wastewater before and after the ion-exchange process,
mixed textile and municipal wastewater after biological treatment
with variable color: weak and intense color,
wastewater before and after the ozonation process, and
wastewater collected directly from the fabric-dyeing house.
The following dyes used currently in the ACP [1, 6, 2] were used for
the investigations.
Sulfur Dyes
Sulphur Khaki G (C.I. Sulphur Green 8:1)*
Sulphur Black WT (C.I. Solubilised Sulphur Black 1; 53186)
*Where possible, the manufacturer's name for each dye is followed in
parentheses by the Colour Index generic name and constitution number. Both
generic names and constitution numbers are absent for commercial dye names not
listed in the Colour Index, third edition. Some dyes listed in the Colour
Index are assigned generic names only; their constitution numbers have not
been determined.
12
-------
Vat Dyes:
Helanthrene Green BS
Helanthrene Olive BT
Indigosol Dyes:
Helasol Yellow GOK (C.I. Solubilised Vat Yellow 4; 59106)
Helasol Grey BL (C.I. Solubilised Vat Black 1; 73671)
Helasol Orange RK (C.I. Solubilised Vat Orange 3; 59301)
Helasol Pink R (C.I. Solubilised Vat Red 1; 73361)
Reactive Dyes:
Helaktyn Yellow DGR
Helaktyn Yellow D5GN
Drimarene Green X-2BL (C.I. Reactive Green 15)
Remazol Brilliant Blue (C.I. Reactive Blue 19; 61200)
Helaktyne Red F5B
Dispersed Dyes:
Synten Rubine P-3B (C.I. Disperse Red 5; 11215)
Synten Navy Blue P-BL
Indanthren Bordeaux RR (C.I. Vat Red 15; 71100)
Synten Azure
Synten Yellow 5G (C.I. Disperse Yellow 5; 12790)
Glacial Dyes:
Natural Azure Salt BT
The scope of investigations included introductory operations intended
to isolate dye compounds from solutions. After the introductory operations
the actual chromatographic analysis was begun with the thin-layer and column
methods, a suitable kind of plate, suitable chromatographic column material
filling, and the best solvents.
Method and Course of Investigations
Introductory Processes--
Before chromatographic analysis began, samples were subjected to vari-
ous introductory processes such as concentration by evaporation, retention
of dyes on column with ion-exchange XAD-4 resin [3], and extraction of
retained dyes with organic solvents [4].
Condensation of samples—In the first stage of investigations the
method of concentration by evaporation was used [5]. After evaporation of
2 or 3 1 of wastewater, about 2 to 5 ml of concentrate with an intense
coloring was obtained. The concentrate thus obtained was subjected to
chromatographic analysis on thin-layer plates. It was found that the con-
13
-------
centration method can be applied to solutions when they are more intensely
colored. In the majority of samples studied, concentration by evaporation
caused the wastewater to pass to a semiliquid consistency before it reached
a color concentration that left distinct spots on the plates.
Further tests of concentration by evaporation were abandoned, since
this method was found to be unsuitable.
Retention of dyes on ion-exchange resins—The ion-exchange bed was
formed by the resin XAD-4, which is polystyrene and bivinyl benzene copolymer
o
with low polarity and pore diameter of 50 A [6]. Before investigations were
started, this resin was adequately cleaned in a Soxlete apparatus by the .
extraction method using methanol once and ethyl ether twice. Extraction was
carried out in each solvents for 8 h. After cleaning, the resin was kept in
methanol in order to guarantee a large active surface.
The test with ion exchange was conducted in glass columns 50 cm high
and 2.5 cm in diameter. The height of the bed was 20 to 30 cm. The resin
layer in the form of suspended matter was placed in methanol on porous glass
covered with a glass wool plug. A glass wool plug was also placed above the
resin. Before investigations began, the methanol was removed and the bed
was washed with 20 ml of distilled water. Dye solutions, as described in
table 4-3, were fed onto the XAD-4 bed from above. Dyes, as compounds
containing chromophor and auxochrome groupings that determine their useful-
ness and color, have the capacity to exchange those groupings with ions in
the bed. Samples of dye solutions were subjected to spectrophotometric
analysis both before they were fed to the column in quantities of 40 ml and
after they left the column. Their transmission was determined in the range
of visible light from A, = 420 to 650 nm for every 10 units.
The results obtained in relation to wavelength were presented on dia-
grams from which the value of the dominant \ was determined. For the value
of the dominant \, determined as a distinct peak, the percentage of dye "
retained was calculated [6]. In the case of graphs which did not contain
distinct peaks, average results of determinations of transmission were taken
from individual divisions.
After the dye had been washed with a constant portion of ethyl ether
(15 ml), the column with the resin was subjected to regeneration [7].
Thirty ml of methanol were added, then removed after 10 minutes contact with
the resin. The resin column was filled again with fresh methanol and
plugged.
The results of investigations from the dye compound retention process
set out in tables 4-3 and 4-4. On the basis of these results we can con-
clude that all the dyes examined were isolated from water solutions to a
considerable degree [figure 4-2]. The highest percentage of retained dyes—
on the average 88.2 percent—was observed for reactive groups, and the
lowest--18.6 percent—for vat dyes (sulfur~18.3 percent; indigosol—81.3
percent) [figures 4-4, 4-5, and 4-6].
14
-------
Extraction methods—In addition to the ion-exchange method, the process
of extraction was also used to isolate color compounds from solutions.
Extraction is the process of the transfer of a defined chemical substance,
dissolved in a fluid phase, to another fluid phase that is not mixed with
the first. In the present investigations, a mixture of the. following sol-
vents constituted an organic liquid phase: isopropyl alcohol: alcohol
n-butyl:ethyl octane in the ratio 30:50:20.
This method was applied to both natural biologically treated wastewater
colored with a constant amount of dye (5 mg/1), and to natural noncolored
wastewater. The dyes were extracted in a 100-ml mixture of the above sol-
vents, as evidenced by the increase in the color intensity of the solvent
layer. For natural noncolored wastewater, extraction was performed from 5 1
of wastewater. The percentage of transmission of the organic bed in the
range of visible light was determined. The results are set out in table
4-5.
On the basis of these results, it appears that the extraction method,
the purpose of which is to isolate color compounds, does not yield high
percentages of extracted dyes. As a result, this method was discontinued,
and the method of retaining dyes in the column with the resin XAD-4 was
accepted as the main preliminary method for isolation of dye compounds from
solution.
Chromatographic Analysis--
Thin-layer chromatography—In the investigations carried out into the
separation of dyes contained in textile wastewater, the thin-layer chroma-
tography method was first used with the application of plates covered with
silica gel, aluminum oxide, and cellulose [8,9]. In the first stage of
investigations a series of preliminary tests were carried out with the aim
of choosing suitable thin-layer plates and eluting solutions appropriate for
the given dye groups. Plates covered with silica gel were chosen as the
best ones. The eluting solvents for the individual groups of dyes are
listed in table 4-6.
A drop of the examined mixture of two or three dyes, isolated from the
wastewater by the method of ion exchange on resin XAD-4, was deposited on
the thin-layer plate. The dyes were washed in 15 ml of ethyl ether. A drop
of the mixture under examination was placed on the starting line, and the
plate was placed in a closed vessel with its edge immersed in the
chromatogram-developing solvent.
Thin-layer chromatography analysis was also used for color compounds
isolated from biologically treated natural wastewater after it had been
condensed and the color retained on the resin layer. Dyes coming directly
from the dyeworks wastewater were also subjected to this analysis. After
chromatograms had developed, individual spots of color, together with the
silica gel, were separated from the bed. The color was washed out with the
solvents specified and was determined spectrometrically. On the basis of
the transmission percentages obtained, the recovery of the corresponding
dyes were determined.
15
-------
Column chromatography—When investigations into the separation of color
compounds were being expanded, the column method was introduced. Dyes
isolated from the following solutions [10] were subjected to separation on
the chromatographic column:
Water solutions of dye, 5 mg/1;
biologically treated wastewater colored with dye, 5 mg/1;
biologically treated wastewater with a moderate natural color;
biologically treated wastewater with an intense specific coloring;
biologically treated wastewater additionally colored with mixtures
(I to V in table 4-4) 50 mg/1 before and after the ozonation
process;
wastewater collected directly from the cloth-dyeing department.
The dyes were isolated from the solutions on the column with the resin
XAD-4. Two to three ether solutions of washed-out dyes were mixed in the
ratio 1:1 and were fed onto the chromatographic column from the top.
Given in tables 4-7, 4-8, and 4-9 are the solvents and chromatographic
column fillings used in relation to dyes isolated from water, wastewater,
wastewater mixtures before and after ozonation, and dyehouse process
streams. Examples of the spectrographic analysis showing the separation of
these dyes by the column chromotographic process are provided in figures 4-7
and 4-8.
Column chromatography was also applied to investigations into the
separation of color compounds coming from natural wastewater collected from
the biological treatment effluent. The chemical compounds given above and
the solvents which develop the chromatogram were used as a carrier (mobile
phase).
After color compounds were isolated from the wastewater by the extrac-
tion method, worse dye isolation results were obtained, (figure 4-9) As a
result of this, investigations of column chromatography in application to
these compounds were limited to tests of biologically treated wastewater
synthetically colored with 5 mg/1 of dye, and of natural wastewater col-
lected from the activated sludge process effluent. After the color com-
pounds had passed to the solvent bed, which was composed of isopropyl
alcohol:n-butanol:ethyl octane (30:50:20), the transmission of this bed in
the range from 420 to 650 nm was examined. The solution was condensed to
20 ml and the chromatogram was developed on the silica gel.
Results of Investigations—
Thin-layer chromatography--The percentage dye recovery from wastewater.
samples synthetically colored with a mixture of two dyes was as shown in the
table on the following page.
These dye recovery percentages are considerably lower than those ob-
tained by the column method for the same dyes. For example, Helanthrene
Green BS showed 15.3 percent dye recovery from the thin-Tayer plate and
32.5 percent recovery with the chromatographic column method; Helasol
16
-------
Pink R showed 12.0 percent recovery from the thin-layer plate and 40.4
percent recovery with the chromatographic column method.
When chromatographic analysis performed on thin-layer plates was used
?n_re1ation to natural wastewater, no positive results were obtained. When
thin-layer plates were applied to natural wastewater after activated sludge,
a legible chromatogram was not obtained because the spot was uniform,
blurred, and yellowish. In this case, the methods of condensation [11] and
ion-exchange resin XAD-4 were used simultaneously as introductory processes.
Column chromatography—The results of separation of color compounds on
the chromatographic column are given in tables 4-3 and 4-4. The dyes sub-
jected to chromatographic analysis were isolated from the solutions by the
method of ion exchange on resin XAD-4 [12,13].
On the basis of the results the following conclusions can be drawn:
1. The dye recovery percentages quoted in table 4-3 indicate that the
column chromatography method is suitable for solutions with a color
compound content greater than 5 mg/1.
2. Table 4-4 indicates that the highest percentages of recovery of color
compounds were obtained for the dyes Helasol Yellow GOK (C.I. Solu-
bilised Vat Yellow 4; 59106) (96.0 percent) and Drimarene Green X-2BL
(C.I. Reactive Green 15) (86.5 percent).
3. A high level of dye recovery was also obtained for wastewater collected
directly from the cloth-dyeing department and for the solutions used in
the ozonation processes for the first four mixtures. The dye recovery
levels following the ozonazation process are lower than those preceding
it. However, for wastewater of a lower color concentration, the column
chromatography method did not yield the expected degree of recovery.
4. In chromatographic studies carried out by the column method on natural
wastewater, from which refractory substances had been isolated by
concentration and by ion exchange, successively, a separation of dyes
was not obtained for any of the carrier substances mentioned.
5. For wastewater containing a characteristic blue-green coloring, after
the separation of color compounds on resin, a blurred chromatogram
without clearly defined color bands was obtained on the chromatographic
column. A measurement of transmission in this case was impossible. In
investigations of wastewater condensed from 5 1 to 1 ml with a specific
green-blue color, a uniform blue band was obtained on the chromato-
graphic column. The dye recovery here was 7.2 percent.
6. The development of a chromatogram composed of dyes isolated from solu-
tions by the extraction method resulted in blurred color bands, which
were difficult to separate at an intensity less than that after ion
exchange. The percentage dye recovery on the column in this case was
as shown in table 4-11.
7. In investigations carried out on wastewater with a natural color, a
uniform, blurred band, like that in the previous investigations, was
obtained on the column.
8. For wastewater with characteristic coloring after initial condensation
and extraction, a uniform band was obtained on the column. The color
recovery percentages—3.5 percent, 4.8 percent, and 2.3 percent, suc-
17
-------
cessively—average 3.9 percent. This result has no practical signif-
icance.
Discussion of the Results of Investigations—
On the basis of the chromatographic investigations carried out with the
aim of isolating, separating, and possibly identifying the color compounds
contained in wastewater from the textile industry, we conclude that chro-
matographic analysis cannot be applied to biologically treated wastewater
because the color concentration is too small to yield legible chromatograms
either in the chromatographic column or on thin-layer plates.
Another reason for the unsuitability of the column chromatography
method in application to wastewater collected at the pilot plant in
Andrychow is the presence of various other organic compounds, such as
phenols, which influence the disintegration of the dye structure and cause
the formation of other compounds in conjunction with particles of dye.
Therefore, identification is impossible, as is a comparison with model
chromatograms.
The same conclusion applies to additionally colored wastewater in which
the presence of other, mainly organic, compounds has a negative influence on
a legible chromatogram, although the content of the dyes added may be suf-
ficient—that is, there may be good division and recovery percentages, but
difficulties with the identification of compounds.
Column chromatography appears to be a suitable method for wastewater
collected directly from the dyeing processes in which the concentration of
color compounds is high and the amount of other organic pollutants is rela-
tively low.
Conclusions
1. TLC and CC methods are not useful for color analysis of biologically
treated wastewater samples collected after physicochemical treatment
processes. The concentration of dye compounds is not high enough to
produce a clear chromatogram. For color analysis, the minimum con-
centration of dye compounds in wastewater necessary to insure a correct
chromatographic analysis is 5 mg/1. Before applying chromatographic
methods of analysis it is necessary to separate dye compounds from
their wastewater or water solutions and transfer them to the organic
layer by means of ion-exchange processes.
2. As a result of the high content of dissolved salts and the required
high degree of concentration of the dye compounds, concentrating those
compounds by evaporation brought no positive results. The mixture be-
came semiliquid before a concentration of dyes capable of producing
distinct bands of color could be obtained.
3. Two essential factors are the choice of the proper adsorbent or the
right type of thin-layer plate, and the choice of a developing phase
for the particular group of dye compounds.
18
-------
4. The column and thin-layer chromatography can constitute the techniques
for separating and controlling the recovery of the dye compounds from
the wastewater sample collected directly from the textile-dyeing de-
partment.
5. The presence of other organic compounds in wastewater, such as phenols,
for the most part exerts an unfavorable influence on the chromato-
graphic pattern and causes the displacement of bands and changes in the
color intensity in comparison to the standard solutions.
6. The investigations showed that chromatographic analysis performed on
thin-layer plates can be applied to qualitative determinations of the
compounds. But for quantitative determinations, this method proved
unsuitable due to the inaccuracy of results arising during the mechan-
ical removal of gel from the base. In quantitative investigations the
column method gave good results.
7. The quantitative determinations carried out lead to the conclusion that
the recovery of the dyes has been determined within an error range of
about 15 percent.
19
-------
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Table 4-1. a. Values of relative extinction at 450 nm
for 10 wastewater samples treated biologically
n
1
2
3
4
5
6
7
8
9
10
Sum
xi
0.58
0.56
0.50
0.46
0.40
0.40
0.49
0.54
0.55
0.54
5.02
(x - x>
VA . A;
0.08
0.06
0.00
0.04
0.10
0.10
0.01
0.04
0.05
0.04
(x - x)2
\ *•: A/
0.0064
0.0036
0
0.0016
0.0100
0.0100
0.0001
0.0016
0.0025
0.0016
0.0374
b. Values of relative extinction at 500 nm
for 10 wastewater samples treated biologically
n
1
2
3
4
5
6
7
8
9
10
Sum
xi
0.40
0.41
0.40
0.30
0.30
0.42
0.43
0.40
0.40
0.30
3.76
C— \
X.j - X)
0.02
0.03
0.02
0.10
0.10
0.04
0.05
0.02
0.02
0.01
(x, - x)2
0.0004
0.0009
0.0004
0.0100
0.0100
0.0016
0.0025
0.0004
0.0004
0.0001
0.0267
29
-------
Table 4-2. a. Values of relative extinction at 450 nm
for 10 wastewater samples treated by means of coagulation
n
1
2
4
fi
7
o
9
10
Sum
xi
0.50
0.50
0.43
0.40
0.56
0.40
0.56
0.50
0.58
0.56
4.99
(x - xl
V A - A )
0.00
0
0.07
0.10
0.06
0.10
0.06
0
0.08
0.06
(Xi - x)2
0
0
0.0049
0.0100
0.0036
0.0100
0.0036
0
0.0064
0.0036
0.0421
b. Values of relative extinction at 500 nm^
for 10 wastewater samples treated by coagulation
n
i
i
•3
O
A
T-
n
•j
6
7
/
Q
o
g
10
Xi
0.40
0.40
0.30
0.30
0.44
0.32
0.36
0.41
0.30
0.38
(xi - x)
0.04
0.04
0.06
0.06
0.08
0.04
0
0.05
0.06
0.02
(X.; - x)2
0.0016
0.0016
0.0036
0.0036
0.0064
0.0026
0
0.0025
0.0036
0.0004
Sum
3.61
0.0249
30
-------
Table 4-3. Dye recovery on column with resin XAD-4 and percentage of
dye retention on chromatographic column
Dye
concen-
tration
in ini-
tial
Dye
group
Sulfu-
ric
Gla-
cial
Vat
Dye recovery
from solutions
on column
resin XAD-4
solu-
Initial tion, %
Name of dye
Sulphur
Black WT
Sulphur
Khaki G
Natural
Azure
Salt BT
Helanthrene
Green BS
Helanthrene
Olive BT
tng/1
Analysis of
column chroma-
tography
%
mg/i
solution mq/1
1.
2.
1.
2.
3.
1.
2.
3.
1.
2.
3.
1.
2.
3.
Water
Wastewater
after bio-
log.
treatment
Water
Wastewater
after
biolog.
treatment
Wastewater 40
from dye-
works
Water
Wastewater
after bio-
log.
treatment
Wastewater 5
from dyeworks
Water
Wastewater
after bio-
log.
treatment
Wastewater 15
from dye-
works
Water
Wastewater
after bio-
log.
treatment
Wastewater 10
from dye-
works
5
5
5
5
,000
5
5
,000
5
5
,000
5
5
,000
12.5
10.5
25.0
22.5
29.2
70
86.1
81.1
18.8
17.7
36.6
24.6
29.5
45.5
0.625
0.525
1.25
1.12
11,680
3.50
4.30
4,055
0.940
0.885
5,490
1.230
1.475
4,550
28.5
33.6
20.6
15.4
40.3
82.0
75.6
73.5
44.4
32.5
55.5
45.5
40.1
86.6
0.179
0.176
0.257
0.172
4,674.8
2.87
3.24
2,976
0.410
0.287
3,046
0.559
0.591
3,940
Combined
percent-
age of
recovery
3.5
3.52
5.1
3.4
11.6
57.4
65.1
59.5
8.34
5.75
20.3
11.2
11.8
39.4
31
-------
Table 4-3 (con.)
Dye
group
Ind1-
gosol
Reac-
tive
Name of dye
Helasol
Yellow GOK
Helasol
Grey BL
Helasol
Orange RK
Helasol
Pink R
Helaktyn
Yellow OCR
Drimarene
Green X-2BL
:.
2.
3.
1.
2.
I.
2.
1.
2.
3.
1.
2.
3.
1.
2.
Initial
solution
Mater
Wastewater
after
biolog.
treatment
Wastewater
from dye-
works
Water
Wastewater
after
biolog.
treatment
Water
Wastewater
after
biolog.
treatment
Water
Wastewater
after
biolog.
treatment
Wastewater
from dye-
works
Water
Wastewater
after
biolog.
treatment
Wastewater
from dye-
works
Water
Wastewater
Dye
concen-
tration
in Ini-
tial
solu-
tion,
mg/l
5
5
35,000
5
5
5
5
5
5
25,000
5
5
30,000
5
5
Dye recovery
from solutions
on column
resin XAD-4
%
mg/l
Analysis of
column chroma-
tography
%
mg/l
Combl ned
percent-
age of
recovery
90
90
85
83
88
70
74
60
64
91
94
95
98
91
91
.5
.8
.6
.5
.4
.0
.1
.3
.4
.2
.6
.7
.2
.5
.8
4.52
4.54
29,960
4.17
4.42
3.5
3.7
3.01
3.22
22,940
4.73
4.78
29,460
4.57
4.59
95.2
96.0
75.0
55.4
50.4
60.3
55.3
56.1
40.4
81.6
76.5
70.5
58.2
90.2
85.6
4.30
4.35
22,470
2.31
2.22
2.11
2.04
1.68
1.30
18,727
3.61
3.36
17,145
4.12
3.92
86.
27.
64.
46.
44.
42.
40.
33.
26.
74.
72.
67.
57.
82.
78.
1
1
2
2
5
2
9
8
0
2
3
4
0
5
5
after
biolog.
treatment
32
-------
Table 4-3 (con.)
Dye
group
Reac-
tive
(con.)
Name of dye
Remazol
BH Hi ant
Blue
Dye
concen- Dye recovery
tration from solutions
1n ini- on solumn
tlal resin XAD-4
solu-
Initlal tlon, % mg/1
solution mg/1
1. Water 5 95.2 4.76
2. Wastewater 5 95.5 4.77
after
biolog.
treatment
Analysis of
column chroma-
tography
Combined
percent-
Si mg/1 age of
recovery
82.6 3.93 78.6
75.2
Helaktyn
Black F-5B
1. Water
2. Wastewater
after
biolog.
treatment
3. Wastewater
from dye-
works
5 71.5 3.57 65.6 3.58 46.9
5 74.1 3.70 60.2 2.22 44.6
25,000 85.4 21,350 65.0 13,877 5F.5
33
-------
Table 4-4. Dye recovery on column with resin XAD-4 and percentage of
dye retention on the chromatographic column
I
II
III
IV
V
Composition mixtures
Natural Azure Salt BT
Helanthrene Green BS
Natural Azure Salt BT
Helanthrene Green BS
Base of Scarlet
Natural Azure Salt BT
Sulphur Black WT
Base of Scarlet
Natural Azure Salt BT
Sulphur Black WT
Helasol Green
Indanthren Bordeaux RR
Helaktyn Yellow
Helasol Green
Indanthren Bordeaux RR
Helaktyn Yellow
Synten Azure
Helasol Yellow GOK
Drimarene Green X-2BL
Synten Azure
Helasol Yellow GOK
Drimarene Green X-2BL
Helaktyn Yellow D5GN
Helasol Grey BL
Helaktyn Yellow D5GN
Helasol Grey BL
1.
la.
2.
2a.
1.
la.
Ib.
2.
2a.
2b.
1.
la.
Ib.
2.
2a.
2b.
1.
la.
Ib.
2.
2a.
2b.
1.
la.
2.
2a.
Process
before ozonation
before ozonation
before ozonation
before ozonation
before ozonation
before ozonation
before ozonation
after ozonation
after ozonation
after ozonation
before ozonation
before ozonation
before ozonation
after ozonation
after ozonation
after ozonation
before ozonation
before ozonation
before ozonation
after ozonation
after ozonation
after ozonation
before ozonation
before ozonation
after ozonation
after ozonation
Color re-
covery of
Initial mixtures
dye on column
concen- with resin
tratlon XAD-4, %
50 60.5
50
50 40.1
50
50
50 40.1
50
50
50 36.2
50
50
50 50.5
50
50
50 44.5
50
50
50 65.0
50
50
50 50.6
50
50
Ff+ £\J • \J
50
50 17.1
50
Analysis
of column
chroma tog-
raphy
combined
% of re-
covery of
Individual
dyes
76.5
32.5
56.1
28.0
52.5
82.6
26.5
50.0
60.2
15.4
44.4
54.8
60.3
24.5
40.1
55.0
26.5
95.0
85.0
24.0
70.5
75.2
46.0
20.0
25.2
14.0
34
-------
Table 4-5. Removal of dyes from wastewater by extraction
Type of dye
Sulfuric
Glacial
Vat
Indigo-
sol
Reactive
Name of dye*
Sulphuric
Khaki G
Natural Azure
Salt BT
Helanthrene
Green BS
Helasol
Yellow GOK
Helasol
Orange RK
Helaktyn
Yellow DGR
% of individual
dye extracted
from colored
wastewater
15.0
59.3
10.9
66.0
62.8
77.5
% change meas-
ured spectropho-
tometrically
-
-
-
-
—
.
Drimarene Green X-2BL
Dispersed Synten Rubine
P-38
Synten
Azure
Natural yellow-green
wastewater
Wastewater with a specific
blue coloring
79.6,
44.3
15.6
15.6
30.2
*See pages 12 and 13 for Colour Index information on dyes in this table.
35
-------
Table 4-6. Fluting solvents for various groups of dyes
Mixtures of dyes* Eluting solvent
Indanthren Bordeaux RR Ethyl alcohol
Helasol Yellow GOK
Helasol Pink R
Sulphur Black tfT Chloroform
Syntene Azure
Helanthrene Green BS
Natural Azure Salt BT Ethyl Octane:
Drimarene Green X-2BL n-propanol (1:1)
Helanthrene Olive BS
Helaktyn Red FSB Methanol:petroleum ether
Helaktyn Yellow DGR (2:1)
Synten Rubine P-3B Ethyl Octane:
Sulphur Khaki G n-propanol:
Natural Azure Salt BT n-butanol: (2:1:3)
Remazol Brilliant Blue ^ Chloroform:acetone:
Helasol Grey BL * isopropanol (3:4:2)
Helasol Orange RK
Indanthren Bordeaux RR Ethyl alcohol:n-butanol
Synten Navy Blue (2:1)
Drimarene Green X-2BL
*See pages 12 and 13 for Colour Index information on dyes in this table.
36
-------
Table 4-7. Column chromatography for dye mixtures in
water and wastewater solution
Dye mixture in water Eluting
and wastewater solution* solvent
Chromatographic column
filling
Indanthren Bordeaux RR
Helasol Yellow GOK
Helasol Pink R
Sulphur Black WT
Synten Azure
Helanthrene Green BS
Natural Azure Salt BT
Drimarene Green X-2BL
Helanthrene Olive BS
Helaktyn Black FSB
Helaktyn Yellow DGR
Synten Rubine P-3B
Sulphur Khaki G
Natural Azure Salt BT
Indanthren Bordeaux RR
Synten Navy Blue
Drimarene Green X-2BL
Petroleum
ether (1:1)
Ethyl
octane
Butanol:
chloroform
(1:1)
Methanol
petroleum
ether
Chloroform
Butanol:n-
propanol
(2:1)
Silica gel
Aluminum oxide
Calcium carbonate
Magnesium oxide
Siliceous gel
Calcium carbonate
Silica gel
Silica gel
Aluminum oxide
Silica gel
Silica gel
Silica gel
Magnesium oxide
Silica gel
Silica gel
Silica gel
Silica gel
*See pages 12 and 13 for Colour Index information on dyes in this table.
37
-------
Table 4-8. Column chromatography for dye mixtures in Table 4-4
Mixture with composition
given in table 4-4
Eluting solvent
I before ozonation
I after ozonation
II before ozonation
II after ozonation
III before ozonation
III after ozonation
IV before ozonation
IV after ozonation
V before ozonation
V after ozonation
Butanol:chloroform (1:1)
Ethyl octane
Butanol:n-propanol (2:1)
Ethyl octane
Methanol:petroleum ether (1:1)
Table 4-9. Column chromatography for dye mixtures from dyehouse
Mixture of dyes from
dyehouse*
Eluting solvent
Column filling
Helanthrene Green BS
Helanktyn Red FSB
Helasol Yellow GOK
Synten Rubine P-3B
Natural Azure Salt BT
Helasol Pink R
Synten Azure
Sulphur Khaki G
Helanthrene Olive BT
Helaktyn Yellow D5GN
Ethyl octane
Petroleum ether +
petrol (8:1)
Butanol:
Chloroform (1:1)
Chloroform
Methanol:
Silica gel
Aluminium
oxide
Calcium carbon-
ate
Silica gel
Magnesium
petroleum ether (1:1) oxide
*See pages 12 and 13 for Colour Index information on dyes in this table,
38
-------
Table 4-10. Percent dye recovery from wastewater
colored with various dye mixtures
% of dye
Dye mixture* Developing solvent recovery
Helanthrene Green BS Chloroform 15.3
Helaktyn Red FSB 18.0
Helasol Yellow GOK Ethyl Alcohol 25.5
Synten Rubine P-3B 30.0
Natural Azure Salt Ethyl octane:
BT n-propanol: 10.0
Helasol Pink R n-butanol: (2:1:3) 12.0
Synten Azure Ethyl alcohol: 5.0
Sulphur Khaki G n-butanol (2:1) 15.0
Helanthrene Olive BT Methanol 35.0
Helaktyn Yellow
D5-GN 45.0
*See pages 12 and 13 for Colour Index infcarnation on dyes in this table.
Table 4-11. Percent recovery from dyes isolated by extraction
Kind of dye* % dye recovery
Sulphur Khaki G 15.2
Drimarene Green X-2BL 10.0
Natural Azure Salt BT 7.5
Synten Rubine P-38 13.6
Helasol Yellow GOK 17.0
Helanthrene Green BS 12.4
*See pages 12 and 13 for Colour Index information on the dyes in this table,
39
-------
SECTION 5
CHARACTERISTICS OF TEXTILE PROCESSES
AND PILOT PLANT OPERATION
DESCRIPTION OF THE ANDRYCHOW COTTON PLANT AND ITS PRODUCTION
The Andrychow Cotton Plant (ACP) is engaged in the production of bed-
clothes, clothing, and tent fabrics from cottons and synthetics. The fab-
rics produced are mainly a mixture of cotton and synthetic fibers, b^t some
are pure cotton. The production of raw materials at ACP during the last few
years has been 30 percent synthetics and 70 percent cotton.
The size of ACP production in the period of research was about
55,000,000 m —about 9,000,000 kg—of fabric per year. ACP uses about 7,800
m3/d of water for technological and other purposes; of this, about 6,000
m3/d is discharged in the form of wastewater. Different kinds of chemical
agents and dyes are used in the production of fabrics. The average yearly
consumption of individual chemicals is set out in table 5-1.
The plant has five production departments: the spinning mill, the
weaving mill, the yarn-dyeing department, finishing plant A, and finishing
plant B.
Because process wastewater is not discharged from the spinning and
weaving mills, these departments will not be discussed in the present
report.
The fiber-dyeing department is a transitional department between the
spinning mill and the weaving mill. Yarn for ready-colored fabrics -is
bleached and dyed here before undergoing the weaving process. The fiber-
dyeing department produces about 12 percent of the total weight of fabrics
produced at ACP, but the technological wastewater from the fiber-dyeing
department is about 17 percent of the total amount of wastewater discharged
by ACP. Fiber treatment consists of dyeing and bleaching. Indigosol, vat,
sulfuric, and reactive dyes are used for the dyeing of pure cotton yarn;
cottestrense and dispersed-vat dyes are used for the dyeing of yarn that
blends synthetic and cotton fibers.
In finishing plants A and B the fabrics are subjected to final treat-
ment. The production processes in the two finishing plants are roughly
identical. Differences lie mainly in the different machines with which the
plants are equipped. Both the size of production and the amount of waste-
water discharged are approximately equal for the two finishing plants
40
-------
(2,500 m3/d each). The schematic plan of finishing plant A is given in
figure 5-1, and that for finishing plant B is given in figure 5-2.
Finishing plants A and B are equipped with modern machines for dyeing
bleaching, singeing, and mercerization. These processes take place with a'
continuous movement of fabrics through the particular machines. As a rule
the machines are multicompartmental. The fabric running through individual
compartments is subjected to successive processing operations. The operat-
ing scheme for each type of dye used in the PAD-STEAM continuous dyeing
machine is given in figures 5-3 and 5-4. Unlike plant A, plant B uses
larger quantities of dyes and employs a PAD-STEAM continuous dyeing machine
that is one washing compartment shorter than the machine used in Plant A.
The operating schemes of the washing, bleaching, and mercerization
processes for both finishing plants are given in'figures 5-5 and 5-6.
Finishing plant A is equipped with a modern Benninger bleaching and washing
machine and modern machines for mercerization and singeing. The machines of
the bleaching house in finishing plant B are older types. Movable reaction
tanks are also used in plant B. Some fabrics undergo treatment in these
before the bleaching or washing process.
Since the ACP is generally a modern factory, and its wastewater is
representative for this type of industry in Poland, the results of the
research conducted there apply to most modern textile plants.
SCOPE OR RESEARCH WORK CARRIED OUT AT THE EXPERIMENTAL
PILOT PLANT IN ANDRYCHOW
Municipal sewage from the town of about 13,000 inhabitants and textile
wastewater from the ACP flows to the combined municipal and industrial
wastewater treatment plant in Andrychow. Other minor industries discharging
pretreated wastewater to the treatment plant are a machinery factory and a
slaughterhouse. The total amount of waste according to the last assessment
in 976 is on the average 12,000 m3/d. The proportion of textile to munic-
ipal wastewater is approximately 1:1. At the municipal treatment plant the
wastewater undergoes mechanical treatment according to the plan presented in
figure 5-7. A part of the wastewater mixed after mechanical treatment was
collected for further treatment at the pilot plant.
The experimental pilot plant consisted of a biological treatment unit
with activated sludge aerated with compressed air, and a building in which
the tertiary treatment plant was installed. The pilot biological plant was
set into operation in 1973. In the period of early operation durinq the
second half of 1973, it operated with:
a 1:1 proportion of municipal and textile wastewater
a wastewater supply rate of 2.67 mVh,
a 6-h aeration time with activated sludge,
2,000 to 5,000 mg/1 of mixed-liquor suspended solids in the aera-
tion tank, and
a sludge volume index of 53.5 to 240.3 mg/1.
41
-------
These parameters were maintained until October 10, 1975, when the proportion
of textile to municipal wastewater was changed to 2:1 to increase the con-
centration of the mixed wastewater. The characteristics of the pilot acti-
vated sludge process operation during the first period are indicated in
table 5-2.
After the change in wastewater proportions, the pollutant concentra-
tions supplied-to the pilot biological treatment plant increased At the
same time, the treatment plant's effectiveness decreased (table 5-3) while
the same operating parameters were maintained for the activated sludge
process. Biologically treated wastewater was fed to the pilot tertiary
treatment plant in accordance with a set timetable. The model treatment
units were assembled from Plexiglas columns 0.12 to 0.15 m in diameter and
differing in height depending on the process requirements.
First of all, investigations of the filtration and adsorption processes
were carried out during the period from February 12, 1974, to August 30,
1975 The pilot plant for study of these processes was constructed accord-
inq to the scheme in figure 5-8. The adsorption process was carried out in
a one-, two-, or three-stage system, and also in a parallel system when
different operating conditions of the adsorption process were evaluated. _
Before reaching the adsorption plant, the wastewater always passed through a
filtration column, on which observations were made of the filtration effects
with different filter media. Separate investigations of the filtration
process were carried out on four additional filtration columns working in
parallel, but with different parameters. Investigations of both processes
were conducted in columns 0,15 m in diameter and 2 m high.
The coagulation process was carried out at the pilot plant in two diff-
erent systems: conventional coagulation in a suspended floe reactor, and
upflow contact coagulation. The conventional coagulation process was car-
ried out in a clarifier with vertical flow, with a layer of suspended floes,
working together with an anthracite-sand filter (figure 5-9.) The clarifier
was 0.3 m in diameter and 4 m high. Investigations were carried out in two
series- the first from June to November 1975, and the second from May to
June 1976. Introductory investigations of upflow contact coagulation on
different filter beds were conducted on two columns 0.15 m in diameter and
3 0 m high, from February to May 1975 (figure 5-10). From June to November
1975 the contact coagulation process was carried out on two columns with
identical beds, for one of which preliminary pH control and oxidation with
sodium hypochlorite was carried out. In August 1976, supplementary investi-
gations of contact coagulation with PH control and oxidation with sodium
hypochlorite were conducted. In this series a filtration column with an
anthracite-sand bed was also installed after the coagulation column.
Pilot investigations of the ion-exchange process were carried out from
September 1975 to February 1976. The scheme of the pilot plant for the
study of this process is given in figure 5-11. Plexiglas columns 0.12 m in
diameter and 2.1 m high were used to construct the plant. Investigations of
the ozone-oxidation process were conducted in reactors formed by columns
0.12 m in diameter and 2.1 m high (figure 5-12), filled with ceramic pieces
to increase the efficiency of the reaction of wastewater and ozone. The
42
-------
pilot investigation of the oxidation process was carried out from May to
August 1976.
After investigations of individual tertiary treatment processes had
been completed, the pilot plant was prepared in order to check the cooper-
ation of selected physicochemical processes. The scheme for this system is
given in figure 5-13.
Investigations covering the combined processes of contact coagulation,
filtration, adsorption, and oxidation were carried out in September and
October 1976. The supplementary series of investigations of the combined
processes consisting of upflow contact coagulation, downflow anthracite-sand
filtration, and two-stage adsorption took place in February and March 1977.
In 1976 the pilot plant was completed for investigations of the reverse
osmosis process (figure 5-14). From December 1976 to March 1977 test inves-
tigations of the process of introductory filtration before hyperfiltration
were carried out. They showed that conventional anthracite-sand filtration
is insufficient for spiral wound membranes and for filtration on a ceramic
micropore filter. As a result, additional tests were performed with an
anthracite-sand filter assisted by low doses of coagulant and polyelectro-
lyte. These also gave negative results, which caused the postponement of
investigations of the hyperfiltration process to May 1977.
Detailed operating parameters of individual process pilot models are
discussed later, together with a description of the performance and the
result of investigations of individual processes. The time-phase diagram
for all processes is given in figure 5-15.
43
-------
B
F ~ dye house
B ~ bleach house
1 ~ PAD-STEAM continuous dyeing machine
2 - THERMOSOL continuous dyeing machine
3 - bleaching unit type Formula Go (Benninger)
U - singeing unit (Benninger -Qsthoff)
5 - mercerization unit ( Benninger)
~~" — cloth run direction
Figure 5-1. Finishing Plant A. Schematic plan of the bleach and dye houses.
44
-------
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and pump
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1. Screen
2. Grit chamber
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4. Primary clarifiers for textile wastewater
5. Biological pilot plant
6. Pilot installation for tertiary
treatment processes
7. Overflow for control of industrial
to municipal wastewater ratio
j f
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Figure 5-7. Schematic plan of the primary treatment plant and the pilot plant in Andrychow.
51
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Table 5-1. Consumption of dyes, chemicals, and auxiliary agents
in the Andrychow cotton plant in 1976
No.
Name
Consumption
in kg/yr
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
Sizing agents (Polotex 80, Quicksolan, starch, etc.) 533,453
Wetting agents, detergents (Pretepon G, Sulfonated
castor oil, etc.) 145,301
Dispersing agents (Solidokoll K, Matexil FAMIV, etc.) 10,369
Apretting agents (Polopret K-3, Ohobotex FTC, etc.) 538,440
Auxiliary bleaching agents 88,346
Other auxiliary agents (antifoaming, fixing, etc.) 4,880
Sulfur dyes 32,188
Vat dyes 73,517
Indigosol dyes 14,417
Reactive dyes • 6,450
Dispersed dyes 45,150
Cottestrense mixed dyes 41,064
Optical whitening agents 10,864
Glacial dyes 1»028
Acid dyes 270
Sulfuric acid (H2S04) 98% 671,090
Acetic acid (CHgCOOH) 80% 196,090
Hydrochloric acid (HC1) 35% 6,430
Formic acid (HCOOH) 85% 8,392
Natrium hydroxide (NaOH) 50% 4,275,840
Liquid glass (Na2Si03) 136,600
57
-------
Table 5-1 (con.)
No.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
Name
Common salt (NaCl)
Sodium sulfate (Na^O-)
Ammonia soda (Na0COo)
£. J
Sodium nitrate (NaN03)
Sodium nitrite (NaN02)
Ammonia water (NH3 aq.)
Sodium bicarbonate {NaHCO,}
Sodium pyrosulfite (Na2S205)
Sodium hydrosulfite (Na^O^)
Sodium sulfide (Na?S)
Aluminum sulfate (A12(SO«)3)
Magnesium chloride (MgCl2)
Zinc nitrate (Zn(N03)2) 35%
Sodium ortophosphate (Na3PO«)
Sodium acetate (CH3COONa)
Hydrogen peroxide (H202) 30$
Sodium chlorite (NaC102)
Sodium hypochlorite (NaOCl)
Potassium dichromate (K2Cr2Oy)
Urea (NH2CONH2)
Consumption
in kg/yr
242,85p
"T
36,060
122,350
19,200
17,200
6,505
3,280
6,480
165,643
47,070
2,100
8,360
4,780
16,980
6,980
612,838
40,050
181,845
47,350
6,800
Total: 8,434,900
58
-------
Table 5-2. Activated sludge process, pilot plant, first period
Average concentration
Influent
Effluent
% Removal
BOD5, mg 02/1
Dichromate COO,
mg 02/1
Permanganate COD,
mg 02/1
123
255
64
16
93
19
87
63.5
71
59
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-------
SECTION 6
FILTRATION PROCESS
INTRODUCTION
Description of the Problem
The sedimentation process does not insure the entire removal of fine
particles of suspended matter. Even with properly working secondary sedi-
mentation tanks, approximately 20 mg/1 of suspended solids remain. More-
over, in the case of a high variability in the composition of wastewater,
which occurs in the treatment of municipal sewage mixed with a considerable
portion of industrial wastewater, disturbances resulting from the poor
settling properties of activated sludge should be taken into account. These
disturbances leave a residue of settlable suspended solids in biologically
treated effluent directed to the tertiary treatment or to the receiving
water. The increased amount of suspended solids in biologically treated
wastewater is particularly undesirable when wastewater is directed to some
further tertiary treatment by physicochemical processes such as adsorption,
oxidation, or reverse osmosis.
One of the most universal and easiest procedures for removal on nonset-
tlable suspended solids is rapid-sand or multimedia filtration. In this
case, the degree of removal of suspended solids and other pollutants depends
on many conditions. No mathematical formula has yet been found to determine
the performance parameters of filtration in relation to the composition of
wastewater and the required effectiveness. It is necessary to establish
criteria for determining the appropriateness of this process and for deter-
mining its parameters. The present investigations are a contribution to the
establishment of such criteria.
Description of the Process
The filtration process has been applied for a long time to the treat-
ment of water containing suspended solids. When filters are applied for the
removal of the suspended solids after chemical precipitation processes,
primarily mineral suspended solids are dealt with. However, the filtration
of biologically treated wastewater involves mainly organic suspended solids—
for example, activated sludge floes. These suspended solids are separated
on a filtration bed through which the wastewater passes. Quartz sand is
used most often as a filter medium. Sometimes other materials, such as
anthracite or garnet, are used in a multimedia filter. A high rate of
filtration of wastewater is most often applied at the rate of from 3 to 25
m3/m2h. The suspended solids retained on the bed are washed out with water
62
-------
or with both water and air. The washing process is carried out in a cycli-
cal way at the end of the filter run. The length of the filter run depends
on the porosity of the bed and the amount of suspended solids retained. The
cycle length is usually limited by the allowable head losses through the
filter.
OBJECTIVES
Since many problems have been encountered in the tertiary treatment of
municipal sewage combined with textile wastewater, investigations have been
undertaken with the following objectives:
To check possibilities of increasing the effectiveness of bio-
logical wastewater treatment by the application of filtration as a
final tertiary process,
to fix the optimum design parameters for the filters, and
to determine the usefulness of filtration of biologically treated
wastewater as a process preliminary to further tertiary physico-
chemical treatment processes such as adsorption, ion exchange,
ozonation, and reverse osmosis.
SCOPE OF INVESTIGATION
Investigations on the one-stage filtration process were carried out
using biologically treated municipal wastewater mixed with textile waste-
water. The following technological schemes were applied:
One filtration bed preceding the adsorption column, and
several filtration columns working in parallel, each having a dif-
ferent filter medium and different hydraulic parameters.
For most investigations, the columns were open.
All the investigations can be divided into two stages:
1. Laboratory scale investigations performed in columns 35 mm in
diameter and 1,500 mm high. Enough wastewater was supplied to
carry out one filtration cycle.
2. Pilot scale investigations performed in columns 150 mm in diam-
eter. After leaving the secondary sedimentation tank, the wast-
ewater was continuously fed to the columns.
The following parameters were determined:
Technological effects of the application of single medium and dual
media beds,
optimum filtration rate,
influence of the wastewater composition on the obtained effects,
effectiveness of particular filter media applied in the multimedia
filtration bed,
head losses,
63
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determination of optimum washing parameters, and
hydraulic characteristics of flow.
PROCEDURE OF INVESTIGATION
Description of General Experimental Conditions
First Stage: Laboratory Scale Investigations—
Experimental installation—Investigations were carried out on an ex-
perimental model apparatus (figure 6-1) including bottles containing bio-
logically treated wastewater to be fed, a blower, a dosing tank, filtration
columns with equipment, and glass bottles used as receivers of the filtrate.
Glass bottles, each of 50 1, were used to store all the biologically treated
wastewater necessary for one experimental cycle. A blower was used to raise
the wastewater to a 10-1 glass bottle used as the upper dosing tank.
Wastewater was fed to the filtration bed by gravity, and the flow was
controlled by means of a floating valve. The wastewater surface over the
bed was at a constant level. The filtration housing of the column consisted
of a glass tube with an inner diameter of 36 mm and a height of 1,500 mm.
In the tube, manometers and sampling ports were installed to measure the
hydraulic pressure at six levels and to determine the wastewater quality
changes at various depths of the bed.
Description of the filtration beds—Anthracite and river quartz sand
with natural shape and rounded edges were used as filter media. Two kinds
of filter bed arrangements, indicated as A and B, were applied. The sup-
porting layer was 13 cm high and always consisted of gravel with a constant
granulation. The filtering layer itself consisted either of sand of varied
granulation (variant A) or of sand and anthracite alternately (variant B).
A precise description of the filter media applied is given in table 6-1.
Procedure—The laboratory scale investigations involved six filter
runs designed to study the effectiveness of the filtration of biologically
treated wastewater.
The samples were collected from the secondary sedimentation tanks, each
in an amount sufficient to carry out one investigation cycle (assumed to
last 12 h). According to the applied rate of filtration, 120 to 350 1 of
wastewater were sampled. For both kind of beds, the applied filtration rate
amounted to 4, 8, and 12 m3/m2h. The parameters of the filtration process
and the results obtained are listed in table 6-2. Results for tests 3, 4,
and 5 are shown graphically in figure 6-2. The pressure versus depth
changes during the filtration cycle are shown in figures 6-3 and 6-4.
Sampling—Samples for the analysis of influent wastewater were col-
lected once for each filtration cycle from a portion of wastewater to be
fed, whereas samples for the analysis of wastewater after filtration were
collected several times from each cycle, the frequency depending on the
duration of the cycle (on the average, three samples per cycle).
Scope of physicochemical analysis—Determinations were made^of the
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following pollution indicators in the samples: Suspended solids, BOD5,
dissolved solids, color, dichromate COD, permanganate COD, and detergents.
The analyses were performed according to the procedures described in sec-
tion 4.
Second Stage: Pilot Scale Investigations--
Experimental installation—The pilot scale investigations were carried
out on an experimental model installation (figure 6-5) mounted at the pilot
plant in Andrychow. The wastewater biologically treated by means of acti-
vated sludge was collected from the secondary tank and pumped to the tank
situated above the filtration columns. The basic task of the 200-1 tank was
to compensate for the hydraulic impacts resulting from the periodic work of
the pump and to stabilize the pressure at the inlet to the filtration col-
umns. The tank did not equalize the wastewater quality, but it did act as a
retention chamber, ensuring a constant supply of wastewater to the filtra-
tion columns during periodic operation of the pump. The flow capacity of
the pump was 30 1/min.
In the filtration columns, the constant wastewater level was maintained
at 0.8 m above the filtration bed by means of a floating valve. Only in the
course of the third investigation series did the filtration bed work under
the higher pressure generated by the layer of wastewater contained in the
filtration column and in the tank. The total wastewater layer height above
the bed at that period was 2 m. The height of the bed was always 1 m. The
flow rate was controlled by means of a valve installed at the outlet of the
column. In the course of the fourth investigation series, a rotameter was
mounted at the outlet of the column to continuously indicate the flow inten-
sity.
The filtration columns were equipped with several side tubes with
T-connections. The vertical manometer tubes, connected to T-connections,
made it possible to continuously observe pressure losses during the filtra-
tion. The second outlet of the T-connector terminated with a valve that
served to collect samples of wastewater from various depths of the bed.
Description of the filtration beds—Anthracite and river quartz sand
with natural shape and rounded edges were used for filtration. The inves-
tigations were carried out using single medium sand beds and dual media beds
consisting of both sand and anthracite.
A description of the filtration beds applied in individual series and
columns is given in table 6-3. For beds B and C, applied for the fourth and
fifth investigation series, the sand and the anthracite curves have been
plotted. From that diagram, parameters d10, d60, and K (figure 6-6) char-
acterizing the bed have been determined. The values determined for the bed
of column B are listed in table 6-4. The determination procedure is given
later in this section.
The filtration columns were made of Plexiglas tubes with an inner
diameter of 150 mm. For the pilot investigations on the filtration process,
tubes from 150-mm to 200-mm diameter are most often used [13,14].
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As there was a possibility of wall effects exerting influence on the
obtained results, measurements of the flow rate distribution in the cross
section of the bed were carried out.
The course of Investigations—The process of filtration was carried out
in such a way as to ensure a continuous supply of filtered wastewater to the
adsorption columns. For that purpose it was necessary to adapt the. investi-
gation period for particular series of the filtration to the length of the
adsorption column operation cycle. The entire investigation cycle of the
pilot scale filtration process was performed in five series, the last two of
which, besides investigations into the rate of pollutant removal, included
measurements of the filtration rate distribution in the bed as well as of
the washing parameters of the beds.
The first series lasted from February 12, 1974, to March 23, 1974. The
filtration process was carried out on the bed described in table 6-3. The
rate of filtration was 5.3 m3/m2h, and the maximum head losses were 900 mm
of water depth. The length of one filtration cycle was on the average 12 h.
The process was carried out continuously for 24 h with a half hour break for
washing, performed at the moment when the losses reached their maximum
assumed value. The washing was done with municipal water. The results are
listed in table 6-5.
The second series was carried out simultaneously with the second ad-
sorption series from April 26, 1974, to May 25, 1974. The difference
between these series consisted in a longer cycle of filtration, amounting to
23 h on the average, caused by increasing the value of head losses from
900 mm up to 1,800 mm of water depth. The same procedure and the same
parameters of the filtration process that were used in the first series were
applied here. The results are listed in table 6-6.
The third series was carried out on one column in the period from
August 28, 1974, to June 30, 1975, with breaks for exchanging the adsorption
beds. This filtration series was concurrent with the third, fourth, and
fifth adsorption series. In this third series a dual media filtration was
applied. The filtration results are listed in table 6-7.
The fourth series was carried out simultaneously in four columns with
various beds and various filtration parameters (table 6-8). Each cycle of
filtration was investigated separately, and the sampling and measurements
were taken from the beginning to the end of the cycle. The cycles were
started in all the columns at the same time, usually about 10 o'clock. At
the beginning and in the middle of the cycle the effectiveness of the re-
moval of suspended solids from each bed layer was checked. Every hour the
head losses at all hydraulic gradient lines were recorded. Pressure versus
depth changes during the filtration cycle are shown in figure 6-13
The fifth series was carried out in one column. The characteristics of
the bed and the parameters of the filtration are given in table 6-3. These
investigations were carried out to check the results obtained in the fourth
series, and the observations were made in the same way as those in the
fourth series. Four filtration cycles took place. Contaminant removal data
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from the first two cycles are given in table 6-9. The investigations con-
cerning the flow rate distribution in the bed cross section that were made
in the course of the fourth series were repeated here. Measurements of the
washing parameters were also taken.
Samp! ing—The method of sampling depended on the procedure and objec-
tives assumed for particular series. For the first through third series the
samples were collected from the filtration column influent and effluent
every hour simultaneously. Then the daily average sample was composed.
If the washing of the filtration columns occurred at the time of sam-
pling, the effluent sample was collected after the filtration column had
been put to work again. In the fourth and fifth series samples were taken
at various periods during the filtration cycle. Samples were taken at the
following time intervals, counting from the beginning of the cycle: 30 min^
60 min, 90 min, 120 min, and afterwards every 120 min until the termination
of the cycle. The samples were taken from the influent and from the efflu-
ent at 5-min intervals. A part of each sample was used for the preparation
of one average sample from the entire cycle, and the remaining part was used
to determine the suspended solids separately for every individually col-
lected sample. Additionally, in several cycles of the fourth and fifth
series the samples were collected at various levels of the bed at the be-
ginning and the middle of the filtration cycle. The washing water samples
were collected from the final portion of washing water after all the water
used for washing the bed had been mixed.
Physicochemical analysis—For the daily average samples combined for
the entire 24 h, the following indicators were determined: pH, alkalinity,
oxygen, permanganate, BGD5, COD, suspended solids, and color. Twice a week
detergents were determined. For all samples taken at random, only suspended
solid determinations were made. The analysis was conducted according to the
procedure described in section 4.
Determination of physical properties of the anthracite and sand— Bui k
density was determined as follows. Using dry cylinders of 250-ml capacity,
the sand or anthracite was compacted to a constant level of 200 ml. Next,
the contents were weighed within 0.01-g accuracy. The bulk density (weight
by volume) was calculated from the formula:
where
G - the bulk of the anthracite contained in the cylinder, in g.
Porosity was determined as follows. Cylinders 250 ml each were filled
with 100 ml of water, and the sand or anthracite that had previously been
weighed was slowly poured in. Then the volume of the mixture was read. The
pore space in percentage was calculated according to the formula:
- x 100 -
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where
a = volume of sand and water mixture in ml,
a, = volume of sand in ml, and
a~ = volume of water in ml.
The specific gravity in g/cm3 was calculated from the formula:
,, - bulk density
S'G' = 100-p ^
Measurements of the flow rate distribution in the filtration bed—The
measurements were carried out using the tracer technique to determine the
flow time of colored wastewater. The coloration of the wastewater was
obtained using a 1 percent solution of vat dye, that is, of helantnrene
green. About 2.5 1 of the dye solution were fed in directly over the fil-
tration bed. The penetration time of the solution through the bed was
observed and measured.
During the fourth series an analysis was conducted to choose the right
kind and amount of dye, as well as to make observations of its penetration
through the bed and to measure the trace flow time through all the bed
layers. The observations were carried out for both clean and contaminated
beds in columns A, B, and D, with the assumed filtration parameters main-
tained (table 6-3). In the course of the fourth series, the coloration of
wastewaters and the observations were repeated twice exclusively for bed C.
Flow velocity of 5 m3/m2h was applied. The penetration of the colored
wastewater wave through particular bed layers was observed. The penetration
time was measured and samples were collected simultaneously every 20 sec
from the second and fourth measurement levels (figure 6-5), as well as from
the effluent from the column. For these samples the concentration of color
was determined.
Measurements of washing parameters—In the fifth series, investigations
were carried out into the method and parameters of washing in relation to
the length of the filtration cycle. These investigations were performed on
a dual media filtration bed with granulation, as in the curves shown in
figure 6-6.
The filter bed was washed either only with tap water [22,27] or with
tap water and air alternately [21,23]. The temperature of the washing water
was kept constant at 8° C. Washing water and air were supplied upwards from
the bottom of the filter, and washings were discharged through the outlet
0.9 m above the bed surface reservoir of a known volume.
The following parameters were measured during the washing period:
Time of washing—the time during which the washing medium is ap-
plied (the washing was terminated at the moment when the differ-
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ence in turbidity of the washing water between the inlet and
outlet was negligible);
intensity of washing—calculated from the formula:
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