United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S2-85/010 Apr. 1985
Project  Summary
Textile  Dyes   and   Dyeing
Equipment:  Classification,
Properties,  and   Environmental
Aspects
S. V. Kulkarni,  C. D. Blackwell, A. L. Blackard, C. W. Stackhouse, and

M. W. Alexander
  New  dyes  are continuously being
developed  to meet  the demands  of
new technology,  new fabrics,  ad-
vances  in  dyeing equipment, and  to
overcome  the serious environmental
concerns  associated  with some ex-
isting dyes. The impact of these new
replacement dyes on the environment
and workers can be assessed by com-
paring  them  with  similar  existing
dyes. For this study, information was
collected  from  the  open literature,
product  technical  brochures, trade
association studies, and visits to two
textile  dyeing operations.  The col-
lected  information   was  used  to
characterize  the physical, chemical,
and  application  properties of  14
classes  of textile dyestuffs.  Informa-
tion collected on textile dyeing equip-
ment was  studied to describe dyeing
procedures, the operation of various
types of textile dyeing equipment, and
to estimate both the amount of textile
dyestuff released to  the environment
from a  typical dyeing operation and
the  extent  of worker exposure
associated with each operation. These
estimates were made on a weight-per-
weight  basis of dyestuffs  to fabric
dyed for typical operations. The plant
visit information was used to verify
data obtained from the literature and
to fill  data  gaps.  This  information
enabled  estimates  to be  made  of
dyestuff releases from actual dyeing
operations for each  type of dyeing
equipment described. All information
was collected on an as-available basis
and included data  generated by site
visits and  discussions with other in-
dividuals familiar with this industry.
  Information on air emissions to the
ambient environment from textile dye-
ing operations  was  collected  and
reported;  however,  little data  were
available on air emissions of dyestuffs
to the ambient air. For data on worker
exposure to airborne dyes,  four 1978
studies by the National Institute for
Occupational Safety and Health were
consulted. Unfortunately,  these
studies were of limited use since they
dealt only with benzidene-based dyes
which  have  been  curtailed  from
widespread use  by  the  industry.
Where  possible, worker  exposure
times were recorded during the plant
visits.
  A data  base from EPA's Effluent
Guidelines  Division  was  accessed:
results of a brief analysis of this base
are reported.  Information  extracted
from the  data  base included  the
number and size range of wastewater
treatment and  pretreatment plants of
various  textile dyeing operations. This
information, separated into direct and
indirect wastewater discharges, was
presented   for  small,  medium, and
large textile dyeing  operations.
  Since there were data gaps in the
area of  the emission/release of textile
dyestuffs to the environment, addi-

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tional  areas of  possible investigation
are  identified,  including  data   to
characterize  worker  exposure  time
and   dyestuff   concentration  levels,
quantities of dyestuffs  purchased  by
textile dyeing operations, and updated
plant  size  data  specific  to  dyeing
operations.  This  information would
create a  larger, more  comprehensive
data  base from  which to  obtain  a
more  realistic   profile  of  the textile
dyeing industry.

  This   Project   Summary  was
developed by EPA's Air  and Energy
Engineering  Research  Laboratory,
Research  Triangle  Park,  NC, to  an-
nounce key findings of the research
project that is fully  documented in
separate  report of the  same title (see
Project Report ordering information at
back).

Introduction
  In 1980, 111  million kg (245 million Ib)
of synthetic  organic  dyestuffs were  pro-
duced  in   the  U.S.  The U.S.  imported
another 13 million kg (29 million Ib), or 12
percent  of  the  domestically  produced
amount of synthetic organic dyestuffs.
About two-thirds of the dyestuffs  pro-
duced  in the U.S. were  used by the  tex-
tile industry for dyeing. Until  recently,
azo-type  acid  dyes,  direct  dyes,  and
pigments  based  on  benzidine and ben-
zidine  congeners were commercially  im-
portant  and  very  popular  dyestuffs.
However, recent  health and environmental
concerns   about  benzidine-based   dyes
have caused dyestuff manufacturers  and
dye  users  to  seek  less toxic  and   en-
vironmentally safer  replacements. In addi-
tion,  new technology,  new fabrics,  and
advances  in dyeing equipment provide in-
centive to develop  new dyes.
  Knowledge of the physical,  chemical,
and  application  properties  of new  data
can  provide valuable information  about
the  dye's  environmental   release  and
worker exposure effects.  One method
used  to  determine this  information  for
new and  replacement dyes  is by compar-
ing  the  properties  of  new  dyes  with
similar dyes within the same dye class for
which  such information is already known.
This report provides a basis upon  which
such a comparison can be made.
 Summary
   Three major areas of the study relate to
 dye class categorization, dye equipment
 categorization, and wastewater treatment
 plant size.
                                      2
Dye Class  Categorization
  Using  general  dye  chemistry as  the
basis for classification,  textile  dyestuffs
are grouped into 14 categories or classes:
(1)  acid  dyes,  (2)  direct  (substantive)
dyes, (3) azoic dyes,  (4) disperse dyes,  (5)
sulfur  dyes,  (6) fiber  reactive dyes,  (7)
basic dyes,  (8) oxidation dyes,  (9)  mor-
dant (chrome) dyes,  (10) developed dyes,
(11) vat dyes, (12)  pigments,  (13)  op-
tical/fluorescent brighteners, and (14) sol-
vent dyes.
  Six  of the above dye  classes  (1-6),
selected   by  EPA's  Office  of   Toxic
Substances, were  the  focus of  intensive
data collection efforts in an  attempt  to
describe  each  class, its chemistry, and
chemical and  physical  properties as fully
as possible. Information  collected for the
remaining eight classes (7-14) was similar,
but  not  as detailed. Selection  of  these
classes (1-6) was  based in part on a pro-
jection of new dye development activities
and concerns about the health and en-
vironmental effects  of  these dyes. The
following paragraphs briefly  identify these
six  classes of dyes and describe their use
by the textile dyeing industry.
  Acid  dyes are  typically  used to dye
acrylics,  wool, nylon,  and  nylon/cotton
blends. They are called acid  dyes because
they   are   normally  applied  to  the
nitrogenous fibers  of fabrics in organic or
inorganic acid  solutions. Chemical  reac-
tions between the dye and  fiber form  an
insoluble color molecule on the fiber.  In
1980, acid dyes accounted for 10 percent
of total  U.S.  dye  production. The three
most commercially  important acid  dyes
are  azo,   anthraquinone,   and   tri-
arylmethane. These dyes are generally ap-
plied as  a liquid at elevated temperatures
of  greater  than 39°C  (102°F). Although
acid dyes may be  used  for transfer print-
ing, this use  is  not  commercially  im-
portant.  In general, these dyes have poor
wet fastness.  Molecular weights  range
from  200  to  900,  and  the  higher the
molecular weight,  the poorer the leveling
(uniformity of dye  uptake) property.
  Direct  dyes are  applied in an aqueous
bath  containing  ionic   salts  and   elec-
trolytes.  These dyes  are normally used to
dye cotton and  other  cellulosic  fibers;
they bond to fibers by electrostatic forces.
In 1980,  13  percent of the dyes produced
in the  U.S.  were  direct dyes.  These dyes
are  highly soluble even in cold  water;
most have solubilities in water from 8 to
40  g/l. A few have solubilities  up to  80
g/f.
   Azoic dyes  are applied  by combining
 two soluble components impregnated in
the  fiber  to  form  an  insoluble  color
molecule. These dye components,  sold as
paste-like dispersions and powders, are
used chiefly for cellulosics, especially cot-
ton.  Dyebath temperatures  of  16-27°C
(60-80°F) are generally used to the shade.
  Disperse dyes  are colloidal  and  have
very low water solubilities. Most of these
dyes  are  used   for   polyester,  nylon,
acetate,  and triacetate  fibers.  They are
usually  applied from a  dye bath  as dis-
persions by  direct  colloidal absorption.
Dye  bath conditions (temperature, use of
carrier) are varied based on the degree of
difficulty  encountered  by  the  dyes  in
penetrating the fiber being dyed. They are
sometimes   applied    dry   at   high
temperatures by  means of a sublimation
process followed by colloidal absorption.
High temperature sublimes the  dye and,
once it is  inside  the fiber, the  dye con-
denses to a solid  colloidal state and is ab-
sorbed on  the fiber.
  Sulfur dyes are used primarily for cot-
ton and rayon. The application of sulfur
dyes  requires  carefully  planned  trans-
formations between the water-soluble  re-
duced  state of the dye  and the insoluble
oxidized form. Sulfur dyes can be  applied
in both batch and  continuous processes;
continuous applications   are   preferred
because of the lower volume of dye  re-
quired.  These dyes generally have a poor
resistance  to chlorine.  In  general, sulfur
blacks   are  the  most  commercially im-
portant colors and are  used where  good
color fastness  is  more  important  than
shade  brightness. Sulfur dyes are  not ap-
plicable to wool or silk  because the fibers
are chemically damaged   by the  dyeing
process.
  Fiber  reactive  dyes derive their name
from  the  fact that they  form covalent
bonds   with  the  fiber  molecules to  be
dyed. Molecules of fiber reactive dyes are
much smaller than the complex molecules
of direct dyes.   Fiber  reactive  dyes are
unique  in  that they become  an  integral
part of  the  textile fiber that  is dyed.
Although  more  expensive  than  direct
dyes, advantages of reactive dyes are ex-
cellent  shade  reproducibility  and  good
leveling properties.  These  dyes also have
outstanding wet fastness.  In 1980, about
2 percent of  the  total dyestuffs  produced
in the  U.S.  were  fiber  reactive  dyes.
These  dyes can be subdivided  into either
"hot"  or "cold" dyeing  groups,  based on
the temperature of application.  Although
silk and nylons can be  dyed  with fiber
reactive  dyes,  the chief  fibers  dyed are
cellulosics  and wool. These dyes are also
popular  for printing  textiles,  since  e
the brightest colors  are wet fast.

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  Fiber  reactive dye products  were first
introduced in 1956; by 1980 there were 66
on  the  market. Of  these,  59  represent
about equal numbers of yellow, orange,
red, and blue dyestuffs.  The remaining  in-
clude black,  brown, green,  and  violet
shades.  By 1982, the  number of  fiber
reactive dyestuffs  listed for sale had  in-
creased to  139,  more than  twice  the
number available in  1980.  This increase,
along with the fact  that the dye  shades
are very reproducible and wash fast,  in-
dicates  a continued  increase  in  impor-
tance of fiber  reactive dyes in the future.
Based on  a  linear regression projection of
the past 10 years' production volumes of
fiber reactive dyestuffs, this  class of dye
is expected to show a 56 percent increase
in  production volume by 1990 to a level of
approximately 19.7 million kg (49.3 million
Ib).  The  fiber reactive  dye  class is ex-
pected  to experience the largest percent-
age  increase in  production of any of the
14 dye  classes by 1990.

Dye Equipment Categorization
   Ten  major  types of dyeing  equipment
are now  in use by the textile  dyeing  in-
dustry.  Some of these machines required
minor operational modifications to accom-
modate the newer dyes and to take ad-
vantage of  recent  advances  in  dyeing
equipment  technology.  The  10  general
types of dyeing equipment are:  (1) beams,
(2) becks, (3) jigs,  (4) jets, (5) package
units,  (6) vats,  (7) semicontinuous  (pad-
batch dye machines), (8) continuous dye-
ing (TAK  dyeing, space dyeing, thermosol
dyeing,   and  pad-steam   dyeing),   (9)
transfer printers,  and  (10)  direct  textile
printers.
   Four  of the 10 classes (2, 7,  9, and  10)
were selected by EPA's Office of Toxic
Substances for detailed study. Selection
was based on the predicted   continued
and predominant use of the equipment in
the textile dyeing  industry.
   The four types of dyeing equipment  are
fully described with respect to operation
methods  and  procedures,   physical
features,  and  the dyeing processes  for
which  they are suitable. Machine  types
also are categorized by the  fabric which
can be dyed  and  then  related  to the dye
classes that typically would be  used with
the  various machine/fabric combinations.
Detailed time/temperature  dyeing  profiles
also  were   developed  for  numerous
fabric/machine/dyestuff combinations.
   The important advantages and features
of these  classes of  dyeing  equipment
were identified along with their limitations
and  disadvantages  in  dyeing  different
types of fabric. The equipment specifica-
tions  are  presented  for  the  currently
available dyeing equipment, and dyestuff
use requirements were estimated for each
machine,  based  on  typical   fabric/dye
combinations.   These  estimates  were
verified  with  information collected during
two plant visits.
  Two  textile   dyeing  operations  were
visited to verify information collected  in
the literature search and  to verify actual
dyeing procedures, attainable dye exhaus-
tion  rates, and  drug  room procedures,
and to determine the typical quantities  of
dye and fabric  used  in dyeing operations.
The  two  plants  visited   were selected
because: (1) small and  large dyeing opera-
tions were represented; (2) four types  of
dyeing equipment of interest were in use;
(3) a commission dyeing operation involv-
ing several dye products was represented;
and   (4)  the  distance  from   Research
Triangle Park, NC, was less than  a day's
drive.  Information  obtained  from these
two  plant  visits  was used to  develop a
mass   balance   for    typical  dye
equipment/fabric/dyestuff  combinations.
  The  mass balance  estimates  indicate
the amount and manner  in which a dye
substance is  released to the environment
from specific types of dye equipment. The
dyestuff release from the  fabric and rinse
water was found to vary  widely  for the
different types of dyeing equipment and
the fabric dyed.  The total amount  of
dyestuff can  be  accounted for  in  the
fabric, in the rinse water,  and in  the at-
mospheric  environmental   release.
Therefore,  rinse time,  rinse volume,  and
dye   exhaustion  rates  are  important
parameters for  estimating environmental
release.  The  following   descriptions   of
each  type of dyeing  equipment  and its
typical mass balance illustrate the variabili-
ty of  dyeing  equipment.
  Beck dyeing  takes place in a U-shaped
box  or trough  with a gradually  curved
bottom. The fabric to be  dyed is placed
on  a  driven  reel  above the box  and  is
allowed to slide down the back  of the
box, travel through the dye liquor in the
box, and then  continually return  to the
reel.  This  procedure  is  continued  until
dyeing is completed. Beck dyeing  is best
suited  to woolen  knit and woven goods
as well as heavyweight fabrics such as
carpets, twills,  and satins.
  Beck dyeing utilizes the exhaustion dye-
ing method which is aided by heating the
dye  liquor  with steam.   In  order   to
decrease  the  dyeing  time, beck  dyeing
machines are pressurized to accelerate the
exhaustion    process.   These   high
temperature  and high  pressure  becks
(jets) are best suited to elasticized fabrics
where  machine  tension  on  the  fabric
could  cause  damage.  Pressure  becks
typically use 3,3007 (858 gal.),  or 3,245 kg
(7,153 Ib),  of water per 454 kg (1,000 Ib)
of fabric dyed; an atmospheric beck uses
twice  this  volume of water  to  dye the
same quantity of fabric. The typical fabric
dyed  in an atmospheric beck is cotton;
polyesters generally are dyed in a pressure
beck.  Dye  exhaustion rates of 90 to 100
percent were achieved depending on the
dye  class  used  and  the  shade of  color
desired. For example, a  medium to light
color was  found to exhaust 100  percent;
whereas, a dark color would only achieve
90 percent exhaustion.
  A  typical atmospheric beck  using sulfur
dyes  on cotton  fabric releases about 0.5
kg (1.2 Ib)  of dye solids per 454 kg  (1,000
Ib) of fabric dyed in its  rinse water  ef-
fluent. This amount  depends  on the ex-
haustion and dye shade desired. An addi-
tional  4.8  kg  (11  Ib)  of dye  per 454 kg
(1,000 Ib)  of fabric dyed leaves  the dye
operation  with the fabric, depending  on
the  exhaustion  and  dye  shade  desired.
Pressure becks (or jet machines)  typically
apply  disperse  dyes  on  polyester. This
operation   releases 1.2  kg  (2.7  Ib)  of
disperse dyes per 454 kg (1,000  Ib) of
fabric  dyed in water  effluent, depending
on the exhaustion and shade desired. The
dyed   fabric  typically contains   11.2  kg
(24.5 Ib) of disperse dye solids per 454 kg
(1,000 Ib) of polyester fabric,  but this can
vary depending on exhaustion  and desired
shades.
  Pad-batch dyeing is accomplished with
a padding  machine that is equipped with
a set of wringers which force  the dyestuff
through the  fabric. Once  the fabric has
been saturated  with   dye, the  fabric  is
developed  in a batch  immersion operation
to exhaust the dye onto  the  fabric. This
process can be used for vat, sulfur, azoic,
solubilized  vat   and  diazotized,   and
developed  direct  dyes. Exhaustion  rates
for this type of  equipment range from 60
to 95 percent, and depend on  the amount
of process time and the fabric/dye class.
Rinse time for this process ranges from 1
hour  to 4 or 5 hours.  Because of the
numerous steps required, this  process is a
large user  of water compared with  other
wet  dyeing operations. Water use ranges
from  6,240 to 9,120f (1,648 to 2,409 gal.),
or 6,232 to 9,110 kg (13,739 to 20,084 Ib),
per 3,175 kg (7,000 Ib) of fabric dyed in a
batch.
  The third type of dyeing equipment in-
vestigated  in detail was a transfer printer.
The  method  most commonly  used  in the
transfer  printing   process  involves the

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direct transfer of a pattern or color from a
printed paper to the fabric. This is a dry
process  and  achieves  almost  complete
color exhaustion onto the fabric. A typical
transfer  printing  operation  purchases its
supply of  transfer paper  and  therefore
does  not generate  any dye waste at the
textile  printing  facility.  The  expended
transfer  paper minus  its dyestuff coating
is discarded with the  plant's refuse.
  Transfer  printing is accomplished by a
sublimation process  in  which  the  solid
(dye)  is vaporized  by  heat and condenses
into a solid  on the fabric when cooled.
Disperse dyestuffs are the dye class most
typically  used for transfer printing onto a
polyester fabric.  Transfer  printing  uses
about 0.5 kg (1.1  Ib)  of disperse dyestuff
per 45 kg  (100 Ib)  of fabric. Some other
methods of transfer printing use a wet or
semiliquid  process, but the dry process
described above is becoming predominant
because  it  is unique,  uncomplicated, and
and requires less  skill  to  operate than
other types of dyeing equipment. In addi-
tion,  the  dry  process  is  suitable  for
polyester fabric,  which has  traditionally
been  one  of the  most  difficult fibers to
dye.  This  process also can be  used on
acetate,  triacetate, and  nylon; its use with
disperse dyes  is limited  because of the
high temperature involved. Its use on cot-
ton, wool, or silk is limited  by the lack of
affinity   and/or  fastness  properties  for
disperse dyes and  because  of cylinder
head  temperatures  as high  as  230°C
(446°F)  that will  scorch  these delicate
fibers.
   The fourth type of textile dyeing equip-
 ment that was investigated  in detail was
 direct textile printing. This method uses a
 combination of mechanical and chemical
 means  to  dye the fabric  substrate. The
 two primary methods of direct printing are
 roller and  screen: in  both, the dyestuff is
 applied  as a print paste or printing ink.
 The paste or ink is  dispersed and  either
 rolled directly onto the fabric (roller print-
 ing) or  extended (screen printing) from  a
 circular  or flat perforated screen onto the
 fabric. Acid  dyes are typically used in this
 process and are  applied  to  nylon knit
 fabrics;  pigments  and reactive  dyes are
 used for cottons.  In actual printing opera-
 tions, 100  percent of the dye is applied to
 the fabric;  consequently,  the  only  en-
 vironmental  dyestuff release  is  via  the
 printed  fabric. However,  some of  the
 dyestuff on  the  printed  fabric  will  be
 released during rinsing. Since this printing
 method results in high quality designs,  it
 is  becoming the  most appealing method
 for coloring designer and fashion apparel.
Wastewater Treatment
Plant Size
  Data  from  EPA's  Effluent  Guidelines
Division were analyzed to characterize the
volume of wastewater effluents from tex-
tile dyeing  operations  and the  general
methods of  treatment. Although this  is
the most current  data  available,  it does
not reflect any changes since it was com-
piled in 1977. The data are based on infor-
mation provided by textile operations from
two   standard  industrial  classifications
(SIC): 223 and 226. These classifications,
covering wool weaving  and finishing mills
and  textile  finishing  (excluding   wool)
plants, were selected  for analysis because
most  dyeing operations fall into  one  or
the other.
  The  data provided by  494 plants per-
forming textile dyeing were analyzed. Of
these, about 30 percent (only  147 plants)
discharge their  wastewater effluent  after
on-site  wastewater treatment.  The rest
pretreat their wastewater  and  discharge it
to  publicly   owned   treatment   works
(POTW).
   Both the indirect and direct discharges
were   separated  into  three   plant size
categories   (small,  medium,   and  large)
based  on  their daily  fabric  production
rates. These categories were  determined
by selecting  the medium-sized plant pro-
duction  rate  range to be  between 0.75
and  1.25 times the overall average daily
production  rate. Plants with  higher pro-
duction rates were considered to be large;
those with  lower  production  rates  were
considered to be small. From this distribu-
tion,  typical  average  plant  production
rates and wastewater volumes were deter-
mined for each  plant size.
   A typical small  plant, directly discharg-
ing to  the surface waters after  on-site
waste   treatment,  produces   14,000  kg
(31,000 Ib) of fabric per day and generates
0.02   m3/s  (0.40   million   gpd)  of
wastewater.   The  typical  medium-sized
plant produces  44,000 kg  (97,000  Ib)  of
fabric per day with a  resultant wastewater
discharge of 0.04  m3/s (0.90 million gpd).
The typical large  direct discharging  plant
produces 107,000  kg  (236,000 Ib) of fabric
per day and discharges an average of 0.08
m3/s  (1.90 million  gpd) of wastewater.
   Typical daily  production rates  for the
small, medium,  and large plants discharg-
ing their wastewater to a  POTW  were
6,000 kg (14,000  Ib),  23,000  kg (50,000
Ib), and 86,000 kg (189,000 Ib), respective-
ly. Pretreatment facilities for these typical
plants were  found to have the following
design capacities:  small,  0.01  m3/s  (0.26
million  gpd); medium,  0.02   m3/s  (0.52
million gpd);  and  large,  0.05 m3/s (1.1
million gpd).  The  design  flow  of  the
respective   POTWs  that  received   the
typical dyeing  plant  effluent averaged:
small,  0.73  mVs   (16.70  million  gpd);
medium,  0.83  mVs  (18.90 million  gpd);
and large,  1.20 m3/s (28.40 million gpd).

Conclusions
  Based  on the information collected for
this study, new dyestuffs will continue to
replace older dyes.  In the textile industry,
the two  dye classes that will experience
the most  growth  are  fiber-reactive and
disperse  (sublimable) dyes.  A concurrent
increase  in the use of new  dyeing equip-
ment  (e.g., the  pressure beck (jet) and
transfer  and direct  printers)  is expected
because  of their  high dyeing  efficiency
and exhaustion  rates. For  these  reasons
and since this type of equipment  uses lit-
tle or no water compare with  other equip-
ment  (e.g., the beam, pad-batch opera-
tion, and atmospheric beck),  many dyers
will reduce the  quantity of  wastewater
and dye  solids discharged to  the environ-
ment.  However, because  the new  dry
printing  method (transfer printing)  uses
dyes  that  sublime,  use  of  this  method
may transfer dye emissions from  a water
medium  to the atmosphere  surrounding
the machine.  Use  of this  method  could
have a greater impact on worker exposure
than  wet  dyeing  methods.  In addition,
both plant visits conducted for this study
revealed  that dye  operations can,  with
proper machine operation, achieve a very
high degree of dye  exhaustion onto the
fabrics. Based on observations at  the two
plants visited, this  effort  is already being
made  to maximize the effective  use  of
dyestuffs and  minimize the  cost  of dye
purchases.

Recommendations
  Several areas were identified where in-
formation  was  incomplete  or unavailable
on  textile  dyeing operations.  In  most in-
stances,  the unavailable  information was
nonexistent; obtaining it would   require
detailed  research  efforts.  In  other in-
stances,   the  information was available,
but the database was incomplete or insuf-
ficient  to  establish   reliable   emis-
sion/release estimates and  trends. The
areas of  textile dyeing operations requiring
additional study are:
  • Developing Information on Properties
    of   Dyestuffs —Most   information
    available  on  physical/chemical
    dyestuff  properties  is   general and
    does  not  describe the  properties of
    specific large  volume dyestuffs now
                                       4

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in use. The use of chemical property
estimation techniques and/or actual
testing  of  specific  dye substances
could develop detailed information in
this  area. This effort could  also be
enhanced  by  preparation   of   en-
vironmental  fate  and   accumulation
estimates for the  dyestuffs, using
recently  published  estimation
methods.
Characterizing  the   Size,  Capacity,
and Dye Use of Textile Dyeing Opera-
tions—The most recent  data available
was from EPA's  Effluent Guidelines
Division and was  about  6 to 10 years
old.  Since that time, new dyes and
fabric  combinations  have  replaced
older   dyestuffs,  fabrics,   and
machines. This currently available in-
formation primarily focuses on textile
finishing operations,  rather than  dye-
ing operations. Additional data collec-
tion efforts  could  focus on textile
dyeing operations, rather than on tex-
tile finishing  operations  as past  data
collection efforts  did.
Developing Data on Worker Exposure
to Dyestuffs—Little  information  was
available in the  literature  on worker
exposure  to   dyestuffs, except  for
benzidene-based  dyes  which  have
been largely dropped from use by the
industry. Parameters to be considered
include: frequency, duration,  and ex-
posure  concentrations  for  workers.
No data were found to characterize
the  type  and   concentrations   of
volatilized dye or solvent  emissions
from dry transfer printing operations
to   the   atmosphere   or  dyestuff
releases  via  the expended  transfer
paper. This,  as  well as other batch
and   continuous   dyeing   methods,
could be investigated with respect to
worker exposure.
Studying  Advanced   Wastewater
Treatment  of Dyes—Much  informa-
tion  was  available  in  the  open
literature on wastewater treatment of
textile effluents. However, these  data
did  not  focus on removing  specific
dyestuffs by  these technologies,  nor
did they address the removal  efficien-
cy  of  advanced  technologies; e.g.,
reverse   osmosis  and   hyperfiltration
for specific dyestuffs.
Investigating  Multimedia Transfer of
Dyestuffs—Both  existing  and   ad-
vanced  candidate wastewater treat-
ment technologies  produce  waste-
water sludge  or other liquid  concen-
trates that must be  disposed of.  Vir-
tually no data were  available for the
 quantity of dyestuffs transferred to
 the residual wastes from treatment of
 textile dyeing wastewater.
 Compiling  Information on  Dyeing of
 Leather and Non-woven Textile Prod-
 ucts—Data on  these  topics  were
 available, but were not a major focus
 of this study.
 Additional  Plant Visits to Textile Dye-
 ing   Operations—Additional  plant
 visits to  collect similar information
 would  broaden  the  data  base for
 plant operations and  dyestuff release
 estimates.   This  study  investigated
 only  two  plants;  more such  visits
 would  be useful  in  obtaining  a
 realistic profile of the textile dyeing
 industry.
S. Kulkarni, C. Blackwell, A. Blackard, C. Stackhouse. andM. Alexander are with
  Radian Corporation, Research Triangle Park. NC 27709.
J. S. Ruppersberger is the EPA Project Officer (see below).
The complete report, entitled "Textile Dyes and Dyeing Equipment: Classification,
  Properties, and Environmental Aspects." (Order No. PB 85-173 771/AS; Cost:
  $31.00, subject to change) will be available only from:
        National Technical Information Service
        5285 Port Royal Road
        Springfield, VA 22161
         Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
        Air and Energy Engineering Research Laboratory
         U.S. Environmental Protection Agency
        Research Triangle Park, NC27711
                                ftU.S.Government Printing Office: 1985 — 559-111/10819

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