\it
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S2-83-027  June 1983
Project  Summary
Closed-Cycle Textile Dyeing:  Full-
Scale  Hyperfiltration
Demonstration
Craig A, Brandon
  Hyperfiltration (reverse osmosis) is a
membrane separation technique that
has been used effectively to desalinate
seawater. Successful desalination mem-
branes were not applicable in many
cases to the harsher industrial effluents.
Because expensive energy,  process
chemicals, and water are used in in-
dustrial processes and then  are dis-
charged to treatment facilities, the use
of various membranes to recover water,
energy, and  process  chemicals was
studied in a series of government-spon-
sored research projects. The results of
the research  led to the current project
of joining  a  full-scale dynamic-mem-
brane hyperfiltration (HF) system with
an operating dye range, a multi-pur-
pose machine with a variety of effluents,
presenting a good test situation for
demonstrating HF recovery equipment
on industrial process effluents.
  The  results of this demonstration
and  other related information show
that an HF recovery system will yield a
payout time of 1 to 5 years where there
are simultaneous benefits for water,
energy, and chemical recovery and/or
where  significant waste treatment
costs can be abated.
  The report  describes the design and
construction of the HF equipment; pre-
sents and  evaluates monitoring data
from 1  year of operation; gives costs
for equipment installation, and opera-
tion and credits for savings  due to
recycle; and describes the primary ob-
jectives of an 18-month project exten-
sion.
  This Project Summary was developed
by EPA's Industrial Environmental Re-
search Laboratory, Research  Triangle
Park. NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the
same title (see Project Report ordering
information at back).


Introduction
  LaFrance Industries, LaFrance, SC, in
cooperation with the U.S. Environmental
Protection Agency, the U.S. Department of
Energy, and the U.S. Department of Interior,
is involved in a project coupling a full-scale
hyperfiltration (HF) system with a pro-
duction dye range: the objective is demon-
strating the practicality of HF in recycling
both hot renovated water and reconstituted
dye formulations from dye wash water.
The technical studies leading to this de-
monstration project have been reviewed,
and the progress of the project through
the design phase has been reported. The
equipment has been in operation for over
12 months, and recycled water is now
used routinely. Laboratory tests of the dye
and auxiliary chemicals reused have been
completed, and an initial full-scale reuse of
chemicals has been tested. The reuse of
dyes and chemicals will be further studied
during the extension of this project (April
1982  through  September 1983).  The
project period covered by this report is
April 1979 through April 1982.

Range Process and Effluent
Characteristics
  The  subject range is used for dyeing,
bleaching, and scouring a variety of velour
fabrics. It consists of a dye applicator,
spiral atmospheric steamer, and a washing
section (Figure 1). The washing section
contains, in sequence, a jet washer, a dip

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                         Plant Water
                           Supply
             Permeate
    Dye Solution
        !
      To Drain


+
1 t


                                                                    \-'
                To Surge Tank
Figure 1.    Continuous dye range schematic.


box. and two Rotojet* washers. The range
operates 3 shifts per day, 5 to 7 days per
week,  controlled at speeds of 9  to 36
m/min, depending on the product Cotton,
acrylic, nylon, rayon, and polyester fabrics,
and their blends are processed.
  Although  several classes of dyes are
used  (direct, basic,  disperse, acid, and
reactive),  and the wash water effluent
components vary in dye type and concen-
tration, the types of auxiliary chemicals are
common to all wash water effluents from
the dyeing operations.  The dye formula-
tions contain dyes, a thickener, surfactants,
and in some cases dye solvents.  While
about 85 percent of the dyes are exhausted
on the fabric, the remaining dyes and most
of the auxiliary chemicals are removed by
the washing process. Analyses of com-
posite effluents from the dye pad applicator
and the plant tap water are presented in
Table 1.
  Table 1  also shows representative con-
centrations  and flow from the washing
section. An important part of the project
was the successful reduction of the flow
rate of wash water through the range by
converting to counterftow and using higher
temperatures. The resulting wash water
flow was reduced from about 400 m3/d
(75 gpm) to 190 m3/d (35 gpm) without
loss of washing effectiveness.


Recovery Process
  The recovery  system and its interaction
with the dye range is shown in Figure 2.
The wash  water is collected continuously
from the range. Despite the lapse of time
between production lots for cleaning the
equipment and filling the dye pad, the
water flow is continued to reduce the color
in the water in the washers (by about 30
percent). A production lot can be treated
in the HF  system as  a "batch" which
contains chemicals from a single dye for-
mulation, when knowledge of the compo-
sition is important to the reuse or disposal
of the chemicals.
  The washing section effluents (HF sup-
ply) are usually highly colored, and removal
of 97 percent of the dyes is considered
necessary to avoid possible staining of the
fabric subjected to recycle water.  The
auxiliary components must also be re-
moved sufficiently to provide wash water
with concentration differences suitable for
effectively washing the fabric.
  The concentrate produced by the HF
unit contains  dye concentrations  much
lower than those in  the dye pad solution,
but comparable concentrations of auxiliary
chemicals.  Based on pilot studies, reuse
of the HF concentrates in dye formulation
is feasible with about 75 percent savings
in auxiliary chemicals and about 10-20
percent savings in dyes, depending on the
dye class. Effective reuse of the residual
dyes  and auxiliary chemicals in the HF
concentrate depends on the ability to add
dyes to achieve the required shade, hue,
and  crocking  characteristics needed in
production.  Reuse of the HF concentrate
can be enhanced by judicious scheduling
of dyeing lots, as to shade and dye class as
well as  by employing the experimentally
determined  guideline of  using only 25
percent  of the auxiliary components in
each reuse dye formulation.  To this end,
Table 1.    Chemical Characteristics of the Dye Flange Effluent

                                        Average Concentration or Flow
Assay
Flow, l/min.
BOD, mg/l
COD. mg/l
Conductivity, \unS/cm
Alkalinity , mg/l
Color, ADMI
Hardness, mg/l
pH
Phenols, mg/l
TOG mg/l
Total Solids, mg/l
Suspended Solids, mg/l
Dissolved Solids, mg/l
Chromium, mg/l
Copper, mg/l
Iron, mg/l
Manganese, mg/l
Nickle, mg/l
Zinc, mg/l
Magnesium, mg/l
Calcium, mg/l
Dye Pad
12-35"
5,400
23,900
1580-28,000
4,150
98,800
C
3.6-10.9
0.84
6,250
20,900
1,730
19,200
5.3
19.2
2.8
0.2
0.1
2.7
10.4
7.4
Composite3
Effluent
138
200
1,200
200-2,000
180
1,750
30
5.0-10.5
_d
325
1,140
45
1,100
0.2
0.2
0.63
0.1
0.007
0.25
8.5
3.5
Tap Water
-
-
9
90
-

9
7.05
-

60
3
57
0.002
-
0.022
-
-

1.00
2.36
(*) Tradename, Binks Manufacturing Co., Franklin
Park, IL
 "Representative values based on measurements at various flow rates of wash water.
 bDye pad flow depends on cloth pickup. Pad drops are added directly to the HF concentrate without
 going through the HF unit
 Values were estimated without averaging.
 ''Sample color interferes with analytical procedure.

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                        Permeate
              Plant
              Water

                I
 \Dye Pad
o

Steamer
"
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additive to match the desired shade for
each lot   No auxiliary  chemicals were
added, and more dye was used than the
original formulation called for.  The final
shade  for  both  lots was  slightly dark,
indicating perhaps  too  much  dye was
added  The techniques and production
procedures for reuse of recovery system
concentrate will be developed during the
extension phase of the project
  Figure 4 shows HF unit  performance
characteristics from data obtained shortly
after the membranes were washed. With
the HF unit in this unfouled condition, all
the dye-range hot water requirements were
supplied  by the recovery system.  As
shown in Figure 4, the HF unit pressure
profile is closely predicted  by  a  mathe-
matical model using the feed fluid char-
acteristics and inlet and outlet flows to
predict the HF unit performance.  As the
unit becomes fouled, the inlet fluid pres-
sure increases until an upper limit is
reached and the inlet fluid bypass opens.
Extensive membrane  fouling has been
experienced.  In attempts to remove the
various foulants, washing has involved the
use of detergents and emulsifiers to re-
move silicones (antifoams), enzymes to
remove carbohydrates (undissolved guar
gum, the dye thickener), acetic acid and
citric acid at pH = 4 to remove hard water
scaling, and dye  solvents to remove de-
posited dye particles and precipitates of
the reaction  of  basic and  direct dyes.
Membrane cleaning frequencies and meth-
ods are continuing to be studied.
  The proper design capacity of the unit
would permit completely closed cycle op-
eration; in fact production of the HF unit
has equaled  1 50  percent of the range
water requirements immediately after each
cleaning of the membranes. Membrane
fouling, however, has limited the average
production of the  HF unit  to about 60
percent of the capacity required for a
complete  closed  cycle  operation.  The
problem of membrane fouling, which will
continue to be investigated during the
extension of the project may be solved by
one  or more of three approaches:  (1)
modification of frequency and duration of
cleaning,  (2) modifications of present
methods of removing membrane foulants,
using various cleaning agents not now
used, and (3) substitution for chemicals
and components currently used in dyeing
to avoid or reduce membrane fouling.

Economics
  The evaluation of the HF process included
an analysis of its  economics.   HF is a
technology that effects pollution control
by recycle and recovery. Capital (including
    1000
     900
     800
     700
     600
 S   500
i    400
     300
     200
      100
             41 gpm. Supply Flow
                                                   5 gpm
                                                   Concentrate
                                                    Flow
                         Measured
                	Model

                Temperature = 88C
                                                            Total System
                                                              Length \
                                                             I
1
                     250          500          750

                               Flow Path Length, meters
                                                           1000
Figure 4.    Single pass membrane unit pressure profile as a function of membrane length.
installation) and operating costs (including
membrane maintenance)  are shown in
Table 2.  Savings from recycle of energy,
chemicals, and water and the reduction of
waste treatment or disposal costs depend
on the  specific conditions at any site. In
Table 2, the potential savings at LaFrance,
when chemical recovery is implemented
and membrane washing procedures are
better developed to maintain 100 percent
unit capacity, result in a payout time of 3.3
years. Even shorter payout periods can be
expected  in industrial  situations where
expensive chemicals can be recovered and
high water and waste treatment costs can
be avoided

Conclusions
  For 12 months a production size HF unit
has been  integrated with a manufacturing
dye range resulting in the full scale recycle
of hot wash water from a dynamic mem-
brane HF system. The results have demon-
strated satisfactory  use of permeate re-
covered from all types  of effluents from
this multi-purpose range.  Although per-
meate  is  always  used when  available,
because of membrane fouling its availa-
                                        bility has been limited to about 60 percent
                                        of the production. Full-scale use of the HF
                                        concentrate to formulate solutions  for
                                        dyeing has been demonstrated in selected
                                        cases. The eventual extent of such reuse
                                        of HF concentrate will depend on experience
                                        and the economic incentive.  Throughout
                                        the 12  months of  demonstration, the
                                        membranes remained stable with respect
                                        to rejection.  It has been demonstrated that
                                        stainless steel tube bundles may be used
                                        in reforming membranes  after  several
                                        months of exposure to wash water. Mem-
                                        brane cleaning and foulant removal pro-
                                        cedures will be developed during the  ex-
                                        tended evaluation period.  No buildup of
                                        solute components was observed in the
                                        permeate during a continuous recycle run
                                        of 4  hours;  thus  the  expected normal
                                        continuous recycle period of 8 to 24 hours
                                        should not be limited by component build-
                                        up.
                                          The capital and operating costs of  HF
                                        were documented.  The payout time for
                                        the capital cost of this demonstration will
                                        be 3.3 years (after taxes) (Table 2) when
                                        the full potential for reuse is achieved.
                                        Where there are simultaneous benefits for
                                    4

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water, energy, and chemical recovery and/
or where significant waste treatment costs
can  be abated by reuse/or by  volume
reduction  of pollutants,  HF will yield an
even shorter payout time.

Recommendations
  The results of the demonstration project
can be enhanced by further study to in-
crease chemical  reuse  and to improve
performance of the hyperfiltration unit.
  Extending this  project will permit this
full-scale installation  to be used to: con-
tinue full-scale reuse testing of HF con-
centrates;  continue documentation of the
operation, including savings, for an addi-
tional 12  months: and study membrane
fouling and develop  better cleaning pro-
cedures.
  A goal of the fu rther study of the reuse of
HF  concentrate could be demonstration
through full-scale implementation with
selected production  lots, including:  pro-
duction scheduling, color matching tech-
niques, and reuse of HF concentrate con-
sisting of  mixtures from several produc-
tion dye lots.
  Reuse of 100 percent of HF concentrate
will probably never be practical. This full-
scale production  unit could be used to
further study the disposal of H F concentrate,
a new form of industrial effluent  The
disposal of HF concentrate, because of the
small volume and high concentration, may
be amenable to disposal by chemical pro-
cessing, not normally considered for waste
treatment
  The applicability of the results of this
demonstration of high temperature dy-
namically formed HF membranes on reus-
able porous stainless steel tubes can be
extended  to many industrial situations.
Sintered metal tubing can be widely applied
to hot, corrosive, and dirt-laden industrial
effluents. The dynamic technique of mem-
brane formation  is inherently versatile,
permitting in-situ membrane replacement
and the use of a wide variety of membrane
materials selected for specific separation
requirements.   Research in membrane
tailoring for selected  important industrial
categories would also be valuable.
Table 2.    Summary of Economics for Lafranee
                                                      Present
               Potential
Capital Costs, $
  HF unit
  Installation

    Total

Operating Costs, $/yr
  Membrane Maintenance
  Operator, Maintenance, Overhead

Total
$300,000
 184,000

$484,000
$ 20,000
  39,000

$ 59,000
$300,000
  184,000

$484,000
$ 20,000
  39,000

$ 59,000
Savings, $/yr
Overhead
Energy
Water and Treatment
Chemicals
Total
Return on Original Investment %
Internal Rate of Return, %
Payout Time, yr

$ 13,000
45,400
6,900
25,000
$ 90,300
-0-
-0-
12

$ 13,000
125.000
20,000
130,000
$288,000
20
24
3.3
  Craig A. Brandon is with Carre, Inc., Seneca, SC 29678.
  Robert V. Hendricks is the EPA Project Officer (see below).
  The complete report, entitled "Closed-Cycle Textile Dyeing: Full-Scale Hyper-
    filtration Demonstration," (Order No. PB 83-193219; Cost: $13.00, subject to
  change) will be available only from:
          National Technical Information Service
          5285 Port Royal Road
          Springfield, VA22161
          Telephone: 703-487-4650
  The EPA Project Officer can be contacted at:
          Industrial Environmental Research  Laboratory
          U.S. Environmental Protection Agency
          Research Triangle Park, NC 27711

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United States
Environmental Protection
Agency
                   Center for Environmental Research
                   Information
                   Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
Css
                                                 AGENCY
                CHICAGO  IL  60&04

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