\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.
-------
Permeate
Plant
Water
I
\Dye Pad
o
Steamer
"
-------
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 = 88°C
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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