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Pollutants of textile industry wastewater and assessment of its discharge limits by water quality standards

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Pollutants of textile industry wastewater and assessment of its discharge limits by water quality standards

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Textile industry is one of the most important and rapidly developing industrial sectors in Türkiye. It has a high importance in terms of its environmental impact, since it consumes considerably high amounts of processed water andproduces highly polluted discharge water in large amounts. Textile mills in Türkiye are required to control their discharge and therefore have started installing treatment plants in the name of environmental protection. The wastewater treatment plants of 11 textile mills in the woven fabric and knit fabric finishing industry were investigated in this study. Performances of the treatment plants were evaluated by in situ inspections and analyses of influent and effluent samples. The cost of the existing treatment plants is also evaluated. For the treatment of textile industry wastewater, biological treatment, chemical treatment and combinations of these are used. Plants utilizing biological treatment rather than chemical processes claim that their preference is due to less excess sludge production, lower operational costs and better COD removal in biological treatment. Waste water parameters in the effluent of biological treatment plants were in compliance with the ISKI (Istanbul Water and Sewerage Administration) discharge standards. However, if sodium sulphate in dyeing process and sulphuric acid in neutralization processes are used before a biological treatment, sulphate in the effluent exceeds 1700 mg/l. This problem can be avoided by using HCl or CO2 rather than H2SO4 in neutralization and NaCl instead of Na2SO4, if the use of Na2SO4 is not necessary.
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Turkish Journal of Fisheries and Aquatic Sciences 7: 97-103 (2007)
© Central Fisheries Research Institute (CFRI) Trabzon, Turkey and Japan International Cooperation Agency (JICA)
Pollutants of Textile Industry Wastewater and Assessment of its Discharge
Limits by Water Quality Standards
Introduction
The textile industry uses vegetable fibres such as
cotton, animal fibres such as wool and silk, and a
wide range of synthetic materials such as nylon,
polyester, and acrylics. The production of natural
fibres is approximately equal to the amount of
production of synthetic materials (of which polyester
accounts for about half) (Commission, 2002).
Because textile operations produce so much
wastewater, mills may be tempted to assume that they
cannot avoid large volumes of wastewater, and
therefore, they may become lax in pollution
prevention. In practice, mills vary considerably in the
amount of water and wastewater pollutants they
discharge. One essential and often difficult step in
water pollution prevention is to accurately and
realistically assess the current status of mill and its
potential for improvement. This assessment is
necessary to target specific waste streams that will
maximize pollution prevention. The first step in a
pollution prevention strategy for water is a thorough
audit and characterization of wastewater from textile
operations (Wood, 1992). Comparing the information
from this audit with benchmark data allows for
realistic goal-setting and economic projections for
water pollution reduction activities. Several options
exist for benchmarking an operation and, hence, for
identifying pollution prevention targets. Fibres used in
the textile industry can be divided into two main
categories: natural fibres (e.g. wool, hair, silk, cotton,
flax etc.) and synthetic fibres (e.g. rayon, nylon etc.)
(Sahin, 1996). Pollutants in wastewater from textile
factories vary greatly and depend on the chemicals
and treatment processes used. Pollutants that are
likely to be present include suspended solids,
biodegradable organic matter, toxic organic
compounds (e.g. phenols), and heavy metals (URL 1).
Many studies have been published on water
pollution from textile operations. Brown and Anliker
summarised the effects of textile effluent on the
environment and the toxicity with respect to fish and
other aquatic organisms, sewage bacteria and plants
(URL 2). For example, suspended solids can clog fish
gills, either killing them or reducing their growth rate.
Other important impact, they also reduce light
penetration. This reduces the ability of algae to
produce food and oxygen (URL 3).
The other parameter, sulphates (SO4=) can be
naturally occurring or as a result of municipal or
industrial discharges. Point sources include sewage
treatment plants and industrial discharges such as
tanneries, pulp mills and textile mills. Sulphates are
not considered toxic to plants or animals at normal
concentrations. In humans, small concentrations cause
a temporary laxative effect. However, doses of several
Abstract
Textile industry is one of the most important and rapidly developing industrial sectors in Türkiye. It has a high
importance in terms of its environmental impact, since it consumes considerably high amounts of processed water and
produces highly polluted discharge water in large amounts. Textile mills in Türkiye are required to control their discharge
and therefore have started installing treatment plants in the name of environmental protection.
The wastewater treatment plants of 11 textile mills in the woven fabric and knit fabric finishing industry were
investigated in this study. Performances of the treatment plants were evaluated by in situ inspections and analyses of influent
and effluent samples. The cost of the existing treatment plants is also evaluated.
For the treatment of textile industry wastewater, biological treatment, chemical treatment and combinations of these are
used. Plants utilizing biological treatment rather than chemical processes claim that their preference is due to less excess
sludge production, lower operational costs and better COD removal in biological treatment.
Waste water parameters in the effluent of biological treatment plants were in compliance with the ISKI (Istanbul Water
and Sewerage Administration) discharge standards.
However, if sodium sulphate in dyeing process and sulphuric acid in neutralization processes are used before a
biological treatment, sulphate in the effluent exceeds 1700 mg/l. This problem can be avoided by using HCl or CO2 rather
than H2SO4 in neutralization and NaCl instead of Na2SO4, if the use of Na2SO4 is not necessary.
Key words: Phytoplankton, estuarine, pollution, tide, floodwaters, creek.
Neşe Tüfekci1, Nüket Sivri1,*, İsmail Toroz2
1 Istanbul University, Faculty of Engineering, Department of Environmental Engineering, 34320, Avcılar, İstanbul, Türkiye.
2 Istanbul Technical University, Department of Environmental Engineering, 80626, Maslak, İstanbul, Türkiye.
* Corresponding Author: Tel.: +90 212 473 70 70 /17651; Fax: +90 212 473 71 80;
E-mail: sivrin@gmail.com
Received 03 July 2006
Accepted 18 June 2007
98 N. Tüfekçi et al. / Turk. J. Fish. Aquat. Sci. 7: 97-103 (2007)
thousand units cause all long-term illness effects.
Sulphates are toxic at very high concentrations.
Problems caused by sulphates are most frequently
related to their ability to form strong acids which
changes the pH. In this way, phosphates are not toxic
to humanbeings or animals unless they are present at
very high levels. Digestive problems could occur
from extremely high levels of phosphate (URL 1).
Textile industry in Türkiye is concentrated in
Istanbul where there exist 116 plants that are
specifically treating wastewaters of textile industry.
Seventeen of these treatment plants are biological, 83
are chemical, 14 are chemical and biological, and 2
are physical and chemical (Ucar, 1995).
The discharge standards for the textile industry
in Istanbul are set by Istanbul Water and Sewerage
Administration (ISKI), which also controls and
inspects the industrial wastewater discharges.
Industries are required to pretreat their wastewaters to
meet the standards set by ISKI, according to which
they are allowed to be discharge to the city sewer
system (ISKI, 1994).
In this study, 11 textile mills that have treatment
facility were chosen to investigate their material
production, use of processed water, wastewater
production, and treatment facility. The cost of
treatment from these plants is also investigated. The
products and processes of these 11 mills are
summarized in Table 1.
When these industries were selected, waste
water treatment plants that included different
treatment methods were considered. The chemical
and/or biological treatment methods used in the
treatment of textile industry wastewater were
characterized, problems in treatment plants were
explained and solutions were proposed.
Materials and Methods
The most important parameters in wastewater
from textile industry are COD (Chemical Oxygen
Demand), BOD5 (Biological Oxygen Demand), pH,
fats, oil, nitrogen, phosphorus, sulphate and SS
(suspended solids) (Tufekci et al., 1998). The influent
Table 1. Production and wastewater flow rates of the mills investigated
Mill Material Process Dyeing Wastewater Flow (m3/day)
A Cotton Cotton Knitting
Dyeing
Washing
Kasar
90% Reactive
10% Direct
Dyeing: 150
Washing: 90
Total: 240
B Cotton Cotton Knitting
Kasar
Dyeing
90% Reactive
10% Direct
300
C Cotton Weaving
Jeans Dyeing
Jeans Washing
Dyeing: 100
Washing: 240
Total: 340
D Cotton Kasar
Dyeing
Washing
Reactive 400
E Polyester
Socks Knitting
Dyeing
Washing
20
F Cotton Kasar
Dyeing
85% Reactive
10% Direct
5% Pigment
300
G Cotton Jeans Washing
Cloth Making
250
H Cotton
Polyester
Kasar
Dyeing
Cloth Printing
80% Reactive
10% Direct
10% Pigment
300
I Polyester
Cord Production
Cord Dyeing
Dispersive 60
K Polyester
Wool
Acrylic
Cord Production
Dyeing
40% Acrylic
20% Polyester
40% Wool
95
L Cotton
Polyester
Cord Production
Mercerized
Kasar
Dyeing
Reactive
Direct
Polyester Dyeing:20
Cotton Dyeing:150
Total: 170
99 N. Tüfekçi et al. / Turk. J. Fish. Aquat. Sci. 7: 97-103 (2007)
Table 2. Measured influent and effluent values and removal efficiencies
Mill A B C D
Parameter Inf Eff. Rem. Inf Eff. Rem. Inf Eff. Rem. Inf Eff. Rem.
BOD5 (mg/l) 293 42 86 370 26 93 600 152 75 420 30.3 93
COD (mg/l) 614 120 80 714 92 87 1200 518 57 980 200 80
SS (mg/l) 56 22 60 120 9 92 300 96 68 300 32 89
TKN (mg/l) 10 7.4 26 10 8 20 30 15.2 49 20 11.3 43
TP (mg/l) 1.3 0.7 46 2 0.8 60 2 0.34 83 4 3.6 10
Grease (mg/l) 34 4 88 40 4 90 50 13 74 40 6.7 83
Mill E F G H
Parameter Inf Eff. Rem. Inf Eff. Rem. Inf Eff. Rem. Inf Eff. Rem.
BOD5 (mg/l) 1140 181 84 715 363 49 520 162 69 410 48 88
COD (mg/l) 1960 877 55 1130 780 31 1030 599 42 900 129 86
SS (mg/l) 653 247 62 420 109 74 670 431 36 230 10 95
TKN (mg/l) 60 49 18 43 27 37 37 17.6 52 19 14.6 23
TP (mg/l) 11 3 73 9 4 55 2,8 0.7 75 2.4 0.2 92
Grease (mg/l) 133 62 53 97 31 68 71 19.4 73 48 6 87
Mill I K L
Parameter Inf Eff. Rem. Inf Eff. Rem. Inf Eff. Rem.
BOD5 (mg/l) 974 186 81 615 242 61 280 112 60
COD (mg/l) 1740 636 63 1605 800 50 720 298 59
SS (mg/l) 600 77 87 470 288 39 180 33 82
TKN (mg/l) 11 1,8 84 92.5 53 43 17 9 47
TP (mg/l) 3 0,33 89 4 0.3 92 3 1 66
Grease (mg/l) 120 65 46 127 32 75 52 9.2 82
Inf.: Influent
Eff.: Effluent
Rem.: Removal Efficiency (%)
and effluent characteristics and efficiencies of
treatment plants of the mills, most of which are
cotton-fabric refining mills and polyester, wool,
acrylic, were investigated in this study. The effluents
values are average of at least 6 samples taken at
arbitrary times (Table 2). The effluent concentrations
of BOD5, COD, SS, TKN (Total Kjeldahl Nitrogen),
TP (Total Phosphor) and Grease were analyzed
according to Standard Methods (APHA, 1998).
Results
These analyses along with the discharge
standards set by ISKI and indicated in the Water
Pollution Control Regulation (SKKY) (ITKIB, 1995)
are also presented in Figure 1 to 8.
It is seen in Table 2 that all the parameters from
mill A are under the discharge limits, except for
BOD5 and sulphate. The results of analysis however
imply that the treatment plant is operated only when it
is inspected by the authorities. When the effluent
characteristics of mill B are examined closely, the
treatment efficiency is close to 90%. The fact that
effluent suspended solids (SS) and BOD5 values are
quite low implies that the sample might have taken
from the supernatant of the final sedimentation tank.
Despite some violations of the limits for BOD5 COD,
total sulphur and pH, it is seen that the treatment
facility of mill C was operated efficiently enough.
The treatment facility at mill D treats 300
m3/day industrial wastewater on top of 100 m3/day
municipal wastewater. It works with high efficiency.
However, the raw water characteristics of this
treatment plant are not above the discharge limits.
When the influent and effluent values are compared, it
seems that a two-stage treatment may not be
necessary for this mill. The analysis carried out at the
treatment plant of mill E shows that TKN, COD and
SS were above the discharge limits of ISKI at 50% of
all times. It is seen in Table 2 that the treatment plant
of mill F was one of the low efficiency facilities.
However, this did not pose a significant problem for
the firm, except for BOD5 and COD. Apart from SS,
there was not a single parameter that caused a
problem for mill G, which is a jeans-washing facility.
When the values given in Table 2 are compared
to the discharge limits, it is seen that the additional
activated carbon unit to the prefabricated chemical
treatment facility is not really necessary for this mill.
The effluent values of mill H is one of the lowest.
When the effluent analysis from mill K is examined,
it is seen that they have a chronic nitrogen problem.
The treatment efficiency for the other parameters is
not very satisfactory either. For this mill, where wool
100 N. Tüfekçi et al. / Turk. J. Fish. Aquat. Sci. 7: 97-103 (2007)
0
50
100
150
200
250
300
350
400
ABCDE F GH I K L
Firms
Discharge Values (mg/l)
Average Effluent BOD5
ISKI Limit
SKKY Limit
Figure 1. Average effluent BOD5 from the mills.
0
100
200
300
400
500
600
700
800
900
1000
ABCDE F GH I KL
Firms
Discharge Values (mg/l)
Average Effluent COD ISKI Limit SKKY Limit
Figure 2. Average effluent COD from the mills.
0
50
100
150
200
250
300
350
400
450
500
ABCDE F GH I K L
Firms
Discharge Values (mg/l)
Average Effluent SS
ISKI Limit
SKKY Limit
Figure 3. Average effluent SS from the mills.
0
10
20
30
40
50
60
ABCD E FGH I KL
Firms
Discharge Values (mg/l)
Average Effluent TKN
ISKI Limit
Figure 4. Average effluent TKN from the mills.
N. Tüfekçi et al. / Turk. J. Fish. Aquat. Sci. 7: 97-103 (2007) 101
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
ABCDE F GH I KL
Firms
Discharge Values (mg/l)
Average Effluent Total Sulfur
ISKI Limit
Figure 5. Average effluent total sulphur from the mills.
0
2
4
6
8
10
12
ABCDE F GH I KL
Firms
Discharge Values (mg/l)
Average Effluent Phenol
ISKI Limit
SKKY Limit
Figure 6. Average effluent phenol from the mills.
0
200
400
600
800
1000
1200
1400
1600
1800
ABCDE F GH I KL
Firms
Discharge Values (mg/l)
Average Effluent Sulfate
ISKI Limit
Figure 7. Average effluent sulphate from the mills.
0
2
4
6
8
10
12
ABCDE F GH I KL
Firms
Discharge Values (mg/l)
Average Effluent Total Phosphor
ISKI Limit
Figure 8. Average effluent phosphorus from the mills.
102 N. Tüfekçi et al. / Turk. J. Fish. Aquat. Sci. 7: 97-103 (2007)
dying with acrylic is also carried out, a combination
of chemical and biological treatment should produce
better results. The influent values of mill L, which
also have a mercerizing unit, are relatively low.
However, the treatment efficiency of this plant is
satisfactory.
Cost of Treatment
The cost of the treatment facilities of the textile
industries investigated in this study is given in Figure
9. The cost of the chemicals included in calculations
in Figure 9 is based on the unit prices as of April
2005.
The cost of electricity is based on the present
motor power of the facility and the assumption that
the treatment facility is operated 24 hours. The mills
that do not have maintenance cost declared that they
carry their maintenance on their own.
The yearly equivalence of the capital cost is
calculated by assuming a 10-year operational life and
20% yearly interest. The total cost per unit wastewater
for each mill includes the capital and operational
costs.
Discussion
It is observed in this study that 11 textile mills
that carry refining of knit and woven fabric have
mostly chemical treatment facilities. In addition, some
mills prefer biological or biological/chemical
treatment. Polyethylene (PE), FeSO4, Alum, Lime,
FeCl3 and several modifications of these chemicals
are used in chemical treatment facilities (Sahin, 1996;
Ucar, 1995). Because of the mandatory use of SO4=
based chemical in several process of textile industry,
high sulphate concentration in effluent is observed. It
will be beneficial to modify some processes in a way
that it would be possible to use less salt for dyeing, to
prefer chlorine instead of sulphate and to use HCl or
CO2 for neutralization. When the effluent values and
discharge standards by national authority are
compared, the parameters other than BOD5, COD and
SS do not require high degree of treatment. If it was
desired to discharge the effluent to receiving
environments rather than to the sewer system,
additional treatment units would require SKKY would
in order to meet their standards. It is possible that
advanced treatment technologies might be used to
treat the wastewater from these industries to a quality
that could allow reuse of wastewater. By this way, the
reduction in the use of processed water along with the
less costly treatment through reuse might contribute to
the faster amortization. It is a priority to consider the
advanced treatment technologies along with the
source reduction of waste rather than limiting the
treatment to single-stage. Like in the European
countries, many firms in textile industry are
concentrated on the use of environmentally friendly
chemicals and processes that use less water (Barclay
and Buckley, 2000). It is imperative for us to carry out
similar studies and to keep up with the technological
developments.
In addition, it is necessary to have educated
operators to run the treatment facilities. ISKI and
similar authorities should provide more strict
mechanisms of control based on the scientific
methods. Moreover, the firms that need to pay the
maximum attention to prevent pollution should be
encouraged by the local and central authorities. As
explained above, if more economical local treatment
facilities are opened, firms which do not require high
degree of treatment can control the pollution more
easily. And these firms should pretreat pH, SS and
temperature before they discharge them into the local
treatment plants. This is a much better approach than
having unfunctional or unoperating treatment
facilities. Between 1986 and 1989, ISKI and mostly
textile industry firms, wastewater of which is
conventional, signed a contract that required these
firms to pay their share in capital and operational cost
of treatment. The purpose was to build a central
treatment facility with this money that would treat
both municipal and industrial wastewater. However,
later on this plan was cancelled and each firm was
required to have its own treatment facility. However,
0,0
0,5
1,0
1,5
2,0
2,5
3,0
LA I CKFDB
Firms
Cost of Treatment ($/m3)
Figure 9. The cost treatment for the ınvestigated facilities.
N. Tüfekçi et al. / Turk. J. Fish. Aquat. Sci. 7: 97-103 (2007) 103
it is becoming harder in Istanbul to inspect whether
these facilities are operated properly. The effluent
phosphor, sulphate, and phenol values are below the
limits set by ISKI and it makes it necessary not to use
such parameters for control. The cost of effluent
analysis at ISKI laboratories will be reduced by these
means.
Conclusion
Certain pollutants in textile wastewater are more
important to target for pollution prevention than
others. For example, most dyeing machines have lint
filters and other primary control measures to keep lint
out of heat exchangers and off of the cloth; therefore,
total suspended solids (TSS) levels are low in raw
textile dyeing wastewater compared to many other
industries. On the other hand, biological oxygen
demand (BOD) and chemical oxygen demand (COD)
are relatively high in slashing, fabric formation, and
wet processing and therefore, are more important
pollution prevention targets. The aquatic toxicity of
textile industry wastewater varies considerably among
production facilities. Data are available showing that
some facilities have fairly high aquatic toxicity, while
others show little or no toxicity. If the discharge of
these facilities is assessed according to EC criteria,
additional treatment units would be required to meet
the standards. Despite the fact that it is not a common
practice in our country, the advanced treatment
technologies might be used to treat the wastewater
from these industries to such an extent of a quality
that could allow reuse of wastewater. By these means,
the reduction in the use of processed water along with
less costly treatment through reuse might contribute to
fast amortization. In addition, it is necessary to have
educated operators to run the treatment facilities.
Local and other authorities should provide more strict
regulations and directives like the EC (EPA, 1996).
References
American Public Health Association (APHA-AWWA-
WPCH). 1998. Standard Methods for the Examination
of Water and Waste Water. 20th ed. APHA
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Barclay, S. and Buckley, C. 2000. Waste Minimisation
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Environmental Protection Agency (EPA). 1996. Best
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... Les colorants indigoïdes peuvent bloquer la pénétration de la lumière du soleil de la surface de l'eau empêchant ainsi la photosynthèse [32]. Ils peuvent également augmenter la demande biochimique en oxygène des eaux réceptrices et réduisent à leur tour le processus de réoxygénation et donc entravent la croissance des organismes photoautotrophes [33]. Les colorants de cuve sont utilisés à une concentration allant de 0.05 à 0.1 g/L [34][35][36][37][38][39][40][41] alors que les colorants indigo sont utilisés à des concentrations de 0.02 g/L [42]. ...
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L’objectif de la présente thèse est l’élaboration de nouveaux matériaux composite éco-compatibles à faible coût à partir de ces deux ressources naturelles marocaine le phosphate naturel et le chitosane. Ces matériaux associés à des entités minérales photo actives permettent l’éliminer des polluants organiques présentes dans certains effluents industriels textiles. Il s’agit de l’élimination de deux colorants textiles l’indigo carmine et l’orange de méthyle par deux procédés de traitement l’adsorption et la photocatalyse. Au terme de cette étude les résultats montrent que : • L’élaboration d’une série de composite phosphate naturel-TiO2 calcinés à différentes températures de 200-600°C ainsi que leur caractérisation par IR, DRX et MEB. • Parmi les composites photocatalyseurs phosphate naturel-TiO2 calcinées, le composite phosphate naturel-TiO2 calciné à 600°C présente le meilleur taux d’élimination du colorant indigo carmine à pH neutre, avec une dose du catalyseur qui ne dépasse pas que 0.5 g/L, un temps de photodégradation de 125 min par irradiation en utilisant des lampes UV de puissance 45W à faible coût énergétique. • La décoloration de l'indigo carmine en présence du phosphate-naturel-TiO2-600°C sous irradiation de lumière UV a été influencée de façon significative par des facteurs opérationnels clés : la concentration de H2O2, la concentration initiale de l’indigo carmine, le pH initial de la solution, les co-ions habituellement présents dans les eaux textiles notamment les ions chlorure, les nitrates, les carbonates les ortophosphates. Il a été noté que l’effet que les anions d'orthophosphates conduisent à la plus grande diminution de la dégradation de l'IC. • La vitesse de photodégradation observée Kap (min-1) est de premier ordre. • Dans le but de déterminer l’influence de la fluoroapatite constituant majeur du phosphate naturel (98%), nous avons élaboré la fluroapatite de synthèse par voie sèche suite à quoi nous avons préparé le composite fluroapaptite-TiO2 calciné à 600°C. Nous avons par la suite mené la photodégradation de l’indigo carmine dans les mêmes conditions de photodégradation sus mentionnées. Les résultats montrent que les eaux carbonatées présentent un milieu favorable pour la photodégradation de l’indigo carmine pour lesquelles nous avons constaté qu’en présence des anions carbonates une diminution appréciable du temps de photodégradation de 220 min jusqu'à 90 min. • L’élaboration du film phosphate naturel-Chitosan-TiO2 ainsi que sa caractérisation par spectroscopie infrarouge et diffraction des rayons X pour l’étude de l’adsorption de l’orange de méthyle. • La capacité d'adsorption maximale de l’orange de méthyle est de 333 mg/g. Les valeurs négatives des paramètres thermodynamiques ΔG° et ΔH°, indiquent le caractère spontané et exothermique de l'adsorption. • L’étudié la cinétique d'adsorption de l’orange de méthyle suit modèle cinétique de pseudo second ordre.
Thesis
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The purpose of this research was to determine the distribution of aluminum (Al) ions across mordanting procedures and characterize the effluent of wool challis fabric and wool yarn premordanted with potassium aluminum sulfate (PAS) at three concentrations (7%, 12%, 17%) by weight of fiber. ATSM D5673-16 Standard Test Method for Elements in Water by ICP-MS (American Society for Testing and Materials, 2016) measured the Al ions in the liquors and substrates. The effluent was characterized by measuring chemical oxygen demand (COD) and total organic carbon (TOC) by utilizing TNTplus®-Method 8000 and Shimadzu TOC-L Series. The Al percentage in the treated liquors for both substrates ranged from 26% to 68%. The findings met the Environmental Protection Agency Al in freshwater limits. The wool yarn absorbed a significantly lower percentage of Al than the wool challis. With the increase of the PAS mordant concentration, the percentage of Al ions detected in the substrates decreased significantly and the Al ions percentage significantly increased in the treated liquors. Thus, the 7% PAS concentration was significantly more efficient compared to the recommended 12% concentration. The TOC and COD values of the effluents met the Code of Federal Regulations for textile mill effluent discharge and Global Organic Textile Standard limits as output; however, dilution and neutralization are required before disposing of the effluents. This research confirmed the safe usage of PAS as a mordant for the selected wool substrates in terms of Al input, disposal with pH neutralization, and discharge standards. Further studies could investigate lower concentrations of PAS, the feasibility of reusing the treated liquors, and the impact of PAS amount to dye color parameters. iv
Chapter
Despite the economic importance of textile industries, the trash/waste generated by textile effluents has become a major problem since it endangers both the health of humans and the environment. The effluents of the textiles are responsible for pollution/contamination of soil, air, and water. The dyeing process is also connected with an environmental issue since washing coloured cloth and discharging the dye wastewater may release from 10 to 50% of chemicals related to dyestuff into our environment. The ineffective dyeing and other finishing processes might responsible for the discharge of wasted dyestuff (200,000 tonnes) into our environment globally. Such dye pollutants have serious health complications for living species. Moreover, colouring agents and microplastics along with their types and harmful effects are taken into consideration in the present study. We reviewed (1) introduction to textile and its importance; (2) processes in the textile sector responsible for environmental pollution especially dyeing processes; (3) environmental pollution, i.e., air, soil, and water and dye pollution; (4) colouring agents and types; and (5) microplastics, its types, and environmental pollution especially human health risks. Arsenic (As), cadmium (Cd), chromium (Cr), SO2, CO2, and NO2 are the air pollutants are also discussed and their health implications are given in this chapter. Similarly, zinc (Zn), mercury (Hg), sulphide, sulphates, phosphates, copper (Cu), and nickel (Ni) are major water pollutants due to textiles, which bear negative impacts on environment and human health.
Chapter
In recent times, the speedy growth of urbanized, industrialized, and populated areas in the world has accelerated the use of nonrenewable energies and has led to the discharge of effluence into air, water, and soil. Of late, dye contamination has received immense awareness due to its stability and latent toxic nature. The dyes represent significant organic contaminants and are distinguished for the harmful consequences on aquatic life and humans especially. Recent advances in technologies have given rise to techniques for removing dyes from industrial and household effluents. In this chapter, the latest methods pertaining to nitrogen-based dye removal from wastewater are discussed. Treatment practices such as sedimentation, flocculation, and coagulation-precipitation as primary treatment methods, along with oxidation, photocatalytic degradation, membrane separation, and adsorption (secondary treatment methods) are discussed. Special attention is given to biochar-based adsorption technologies, especially normal and activated biochar.
Thesis
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Industrial sector is the largest user of energy in India and many parts of the world. More than 50% of the total energy produced in the country is utilized by the industries to operate various equipment's. The increased use of energy has raised serious concern about the energy charges and demand. In textile industries most of the energy requirements are met through steam and electrical energy. Energy crises, increase in energy cost and product demand are the major factors, which make these textile sectors to move ahead towards the energy efficient technologies and to adopt the energy conservation techniques. In view of this, a detailed energy performance study has been conducted in one of the leading textile industries to identify the energy saving potential. In Indian textile industry, the number of factors affect on energy consumption. A detailed study was conducted for the small scale textile industry for the various processes involved, operating parameters, and energy requirements during processes including different losses etc. The optimization of variable parameters in dyeing process were conducted on experimental setup to study the effect of identified variables such as process time, process temperature and mass to liquor ratio (MLR) in order to achieve acceptable good quality of cotton coloured products. Energy efficiency is a significant part of a company’s ecological strategy. Decreasing energy losses and recovering the waste energy are of enormous importance. This waste energy in the form of heat can be extracted and reused in further useful applications for the energy saving purpose. Here, an effort has been taken to build up a heat recovery system, which can extract waste heat energy from hot slurry. This extracted heat energy is used for further dyeing process, which preheats the necessary water for dyeing process and ultimately saves energy. A shell and tube type heat exchanger construction is used for this setup. There are different parameters which can affect the heat transfer rate, directly or indirectly. The ‘Interpretive Structural Modeling (ISM)’ approach, which is used to develop a model, will logically identify the relation between these factors and estimate the level of significance of each one of them. From the critical review of literature and discussions with the experts from the Industry and academics, fifty five (55) factors have been identified which can either directly or indirectly enhance the heat transfer rate. The developed ISM model partitioned 29 identified factors that are categorized into four groups and five levels of hierarchical significance. From the MICMAC analysis it is observed that the following four factors have major effect on rate of heat transfer. i) Mass flow rate of working medium (water). ii) Mass flow rate of working fluid (slurry) iii) Temperature of working fluid (slurry) iv) Temperature of working medium (water). To scrutinize the effect of key parameters on the response, full factorial design of experiments technique, which is popularly known as Taguchi method is used. The present experimental work, the four parameters each at three levels viz. mass flow rate of water, mass flow rate of slurry, temperature of slurry and MLR are selected. From this analysis the optimum performance parameters combination for maximum rise in water temperature of 8.93⁰C is A1B2C3D2 . The design of experiment technique is used separately for MLR 1:6, 1:9 and 1:12 is concluded that for maximum heat transfer the optimum combinations of parameters are A1B1C3 , A1B2C3 and A1B3C2 respectively. The mass flow rate of water and temperature of slurry are the key design factors to achieve the higher heat transfer rate. The statistical tool such as Multiple Regression Analysis is widely used for development of conventional predictive modeling. This tool helps the problems having output parameters influenced by several input parameters. The objective is to optimize the output response. In this work, the first and second order mathematical model was developed using Multiple Regression Analysis. In order to investigate the influence of operating parameter on output response measured in terms of temperature difference/rise in water temperature (∆T), the mathematical model is generated for ∆T, which shows the ∆T increases with rise in mass flow rate of slurry and temperature of slurry. But, it decreases with increase in mass flow rate of water. Huge amount of fossil fuel and electricity power is required for different Textile Industrial processes. The new technique ‘Grey Relational Analysis’ is used. To estimate environmental pollution due to burning of fossil fuels in terms of CO2 emissions, In this analysis the optimal performance process parameters are designed to have maximum rate of heat transfer / rise in water temperature (∆T) and minimum CO2 emission. The process parameters studied are mass flow rate of water, mass flow rate of slurry, Temperature of slurry and Mass to Liquor Ratio. Using multi-criteria objective optimization technique i.e. GRA, the whole system is also optimized for maximization of ∆T and minimizing CO2 emission. In this analysis the optimum combinations are obtained in the form of Grey Relational Grade. The Grey Relational Grade is calculated from Grey Relational Coefficients of weight of fuels, cost of fuels and CO2 emission. For maximum ∆T and minimum CO2 emission the overall optimum combination is A1B2C3D2 and optimum values of process parameters are Mass flow rate of water 40 LPM, Mass flow rate of slurry 56 LPM, Temperature of slurry 65⁰C, and Mass to Liquor Ratio 1:9. Due to the production process limitations in Industry, it was not possible to use the MLR 1:9 (which was found optimum) then one can also use MLR1:6 with combination A1B1C3 or MLR1:12 with combination A1B3C2. From above analysis carried out, it is resulted as one can save approximately Rs 4,18,888/- per annum by using wood as a fuel, whereas coal or furnace oil as a fuel one can save Rs 80,811/- and Rs 1,89,069/- per annum respectively.
Article
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Textile effluents are highly colored for synthetic dyes, cause significant water pollution due to high pH, TDS, EC, BOD, and COD content, and are harmful to aquatic species. Among different treatment processes, biological treatment process is considered as a promising approach. In this investigation, a mixed aerobic bacterial consortium was used for the treatment of wastewater. In addition, the fenton process with a normal sand filter was used for treatment and compared with the biological method. The mean values of BOD, COD, TDS, EC, DO, and pH in the raw wastewater indicated that the effluent was highly contaminated according to Bangladesh standard (ECR, 1997). Both the biological treatment process and fenton process separately showed promising removal of pollution load. The aerobic mixed bacterial consortium reduced TDS (66.67%), EC (60%), BOD (91.67%), and COD (85.45%) and fenton process reduced TDS (74.71%), EC (55.11%), BOD (88.33%), and COD (83.63%) compared to the raw effluent bacterial consortium simultaneously degraded dyes and decolorized the wastewater from dark deep green to transparent. Color removal for the mixed aerobic bacterial process after 72 hours of aeration was 58.57% and for the fenton process with a normal sand filter was 80%. BOD and COD removal percentages for aerobic mixed bacterial consortium showed higher removal efficiency than the fenton process with a normal sand filter. Though 92 hours of aeration showed the maximum satisfactory result, aeration time could be reduced to 72 hours which also satisfied the Bangladeshi standard (ECR, 1997).
Article
Full-text available
Foreword This second volume of the Guide contains a series of worksheets designed to aid the industry in conducting an assessment of their performance and identifying areas where savings can be made by implementing a waste minimisation programme. These worksheets were developed as a result of a number of waste minimisation audits undertaken by the Pollution Research Group within the textile industry. It was felt that if there was a standard set of worksheets specific for textile processing, it would simplify the process of data collection and analysis, and aid in identifying areas for improvement. Consequently, a two year project, funded by the Water Research Commission, was initiated to develop these worksheets. An attempt has been made to present as complete a set of worksheets as possible to cover the majority of aspects relating to wet textile processing. In addition, they have been field tested by a number of students, peer reviewed by academics and industrialists, and modified accordingly. This does not imply that the worksheets are rigid in structure and they should be altered as required for individual needs. Any suggestions to improve the guide would be welcomed by the authors which in part, is the reason for the worksheets being presented in a ring-bound file to enable easy updating. Please use the form provided at the back of this volume for your comments. We trust that these worksheets will be a useful tool for the textile industry to undertake a self-assessment of their performance and set goals for improvements.
Article
Ever-tightening regulations on releases to the environment have become a major business factor for the chemical industry. The Organic Chemicals, Plastics, and Synthetic Fibers (OCPSF) effluent guidelines have required many manufacturing sites to expand or upgrade their wastewater treatment plants (WWTP) at considerable cost. Du Pont has recognized the need to shift the emphasis from “end-of-pipe” treatment to waste reduction and elimination at the process source. The Du Pont Belle, West Virginia plant is implementing a program to comply with the OCPSF effluent guidelines by reducing the organic waste load to the WWTP, with secondary emphasis on upgrading the facility for more efficient treatment. This program will reduce the WWTP load by 50%, control priority pollutants at their source and minimize future shock loads from nine processes. This approach will save over $7 million of the investment that would have been required if the effluent reductions were achieved only from WWTP modifications. BOD loads have been reduced to date by over 40% and forecast permit exceedances have dropped from 19 to 2 since 1987. Other anticipated benefits of the waste minimization program are reduced sludge production and volatile organic emissions, as well as greatly improved product yield in one process.
Article
The textile industry is one of the leading sectors in Turkey in terms of economic development. This industry has a variable structure concerning water consumption, raw materials and chemicals used during manufacturing and technologies applied. The dynamic profile of the sector affects the wastewater characterization leading to non-standardized wastewater treatment technologies. In this study, the influent and effluent streams of nine wastewater treatment plants of woven and knit fabric finishing industry were analyzed. The investigated parameters, including BOD5, COD, total nitrogen, phosphorus and others, were compared with the current legislative limiting values.
Treatment of woven and knit fabric finishing mills effluent and treatment cost
  • Y Sahin
Sahin, Y. 1996. Treatment of woven and knit fabric finishing mills effluent and treatment cost. MSc. thesis, Istanbul : Istanbul Technical University.
Discharge Standards for Sewere System Discharges for Industrial Wastewaters
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ISKI. 1994. Discharge Standards for Sewere System Discharges for Industrial Wastewaters, The Official State Bulletin, No: 18340. Istanbul.
Turkish Textile and Apparel Industry, General Secretariat of ITKIB
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ITKIB. 1995. Turkish Textile and Apparel Industry, General Secretariat of ITKIB, Research Development and Legislation Department, Istanbul, 16 pp.
Treatment of wowen and knit fabric finishing mills effluent
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Ucar, S. 1995. Treatment of wowen and knit fabric finishing mills effluent. MSc. thesis, Istanbul: Istanbul Technical University.