U.S. Environmental Protection Agency Industrial Environmental Research CDA finD/7 7fi
Office of Research and Development Laboratory
Cincinnati. Ohio 45268 December 1976
ENVIRONMENTAL
CONSIDERATIONS OF
SELECTED ENERGY
CONSERVING MANUFACTURING
PROCESS OPTIONS:
Vol. IX. Textile
Industry Report
Interagency
Energy-Environment
Research and Development
Program Report
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S.
Environmental Protection Agency, have been grouped into seven series.
These seven broad categories were established to facilitate further
development and application of environmental technology. Elimination
of traditional grouping was consciously planned to foster technology
transfer and a maximum interface in related fields. The seven series
are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from
the effort funded under the 17-agency Federal Energy/Environment
Research and Development Program. These studies relate to EPA's
mission to protect the public health and welfare from adverse effects
of pollutants associated with energy systems. The goal of the Program
is to assure the rapid development of domestic energy supplies in an
environmentallycompatible manner by providing the necessary
environmental data and control technology. Investigations include
analyses of the transport of energy-related pollutants and their health
and ecological effects; assessments of, and development of, control
technologies for energy systems; and integrated assessments of a wide
range of energy-related environmental issues.
This document is available to the public through the National Technical
Information Service, Springfield, Virginia 22161.
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EPA-600/7-76-0341
December 1976
ENVIRONMENTAL CONSIDERATIONS OF SELECTED
ENERGY CONSERVING MANUFACTURING PROCESS OPTIONS
VOLUME IX
TEXTILE INDUSTRY REPORT
EPA Contract No. 68-03-2198
Project Officer
Herbert S. Skovronek
Industrial Pollution Control Division
Industrial Environmental Research Laboratory - Cincinnati
Edison, New Jersey 08817
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF'RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
For sale by the Superintendent of Documents, U.S. Government Printing Office. Washington. D.C. 20402
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DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publica-
tion. Approval does not signify that the contents necessarily reflect the
views and policies of the U.S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.
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FOREWORD
When energy and material resources are extracted, processed, converted,
and used, the related pollutional impacts on our environment and even on our
health often require that new and increasingly more efficient pollution con-
trol methods be used. The Industrial Environmental Research Laboratory -
Cincinnati (lERL-Ci) assists in developing and demonstrating new and im-
proved methodologies that will meet these needs both efficiently and
economically.
This study, consisting of 15 reports, identifies promising industrial
processes and practices in 13 energy-intensive industries which, if imple-
mented over the coming 10 to 15 years, could result in more effective uti-
lization of energy resources. The study was carried out to assess the po-
tential environmental/energy impacts of such changes and the adequacy of
existing control technology in order to identify potential conflicts with
environmental regulations and to alert the Agency to areas where its activi-
ties and policies could influence the future choice of alternatives. The
results will be used by the EPA's Office of Research and Development to de-
fine those areas where existing pollution control technology suffices, where
current and anticipated programs adequately address the areas identified by
the contractor, and where selected program reorientation seems necessary.
Specific data will also be of considerable value to individual researchers
as industry background and in decision-making concerning project selection
and direction. The Power Technology and Conservation Branch of the Energy
Systems-Environmental Control Division should be contacted for additional
information on the program.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
111
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EXECUTIVE SUMMARY
The textile industry is extremely diversified with many plants, differ-
ent types of raw materials, and many end products. Processing operations
also reflect the diversity.
In 1971, total energy use was about 0.54 quads (0.54 x 10 Btu) equiva-
lent, according to the Census of Manufactures, with 66% of the total con-
sumed by four SIC segments, namely: weaving mills-cotton (SIC 221), and
synthetic (SIC 222), knitting mills (SIC 225), and textile finishing (SIC
226). About 60% of the total energy used is consumed in wet operations, such
as fabric preparation, dyeing, and finishing. A major fraction is spent in
heating and evaporation of water, so water conservation (or elimination of
water use) represents a crucial part of the analysis. Natural gas is used
for many drying and heat-setting operations. Although natural gas use is
necessary with present equipment, significant economies can be achieved.
To cover the points just listed, we elected to study the following models
as energy conserving process options:
Integrated knit fabric mill using advanced processing,*
Integrated knit fabric mill using solvent processing, and
Integrated woven fabric mill using advanced processing.
Thus, the models cover weaving or knitting, combined with finishing
operations.
Advanced processing of knit fabrics results in a 50% reduction in energy
use from the base case and we conclude that advanced processing offers lower
energy costs and lower pollution control costs for a somewhat higher capital
investment. Therefore, adoption of advanced processing might be expected
for replacement capacity and for capacity expansion.
All-solvent processing of knit fabrics offers an energy saving of 70%
from the base case in our hypothetical example. Unfortunately, solvent pro-
cessing (for knit fabrics) has not yet been developed technically to the
*Advanced Processing is based on minimizing water use,
iv
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point where it could be applied widely, although specialized applications do
exist (e.g., solvent scouring). Potential solvent losses may present eco--
nomic and environmental problems and require further study.
Advanced processing of woven fabrics results in a 57% reduction in
energy consumption, lower energy costs, and lower pollution control costs.
One unit operation, recovery of polyvinyl alcohol (PVA) size looks quite
attractive economically, and accounts for much of the reduced effluent load.
Wider application of PVA recovery systems needs to be demonstrated.
The average plant in the textile industry can still achieve energy sav-
ings by efficient operation, water conservation and waste heat recovery with
a minimum captial investment. Beyond that point, further substantial reduc-
tions are possible, as indicated by the models developed in this study, with
appropriate capital investment. The benefits of advanced processing of knits
and woven fabrics are sufficient to suggest that it will be adopted in some
form for much of capacity replacement or expansion. The models developed
should be applicable (with some modification) to other important segments
of the textile industry; e.g., carpets and yarn dyeing.
Advanced processing for knit and woven fabrics reduces pollution problems
primarily from a reduction in water use (hence, reducing the hydraulic load
on the biological waste treatment plant). Thus, energy conservation and
effluent reduction are complementary.
All-solvent processing practically eliminates water pollution problems,
but the loss of solvent (typically chlorinated solvent) is a potential occu-
pational health and environmental problem. The energy savings from this route
may not be as attractive as the model suggests, if substantial additional
energy is required to adequately control air pollution.
This report was submitted in partial fulfillment of contract 68-03-2198
by Arthur D. Little, Inc. under sponsorship of the U.S. Environmental Protec-
tion Agency. This report covers a period from June 9, -1975 to January 30, 1976.
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TABLE OF CONTENTS
FOREWORD ill
EXECUTIVE SUMMARY iv
List of Figures ix
List of Tables x
Acknowledgments xii
Conversion Table
I. INTRODUCTION 1
A. BACKGROUND 1
B. CRITERIA FOR INDUSTRY SELECTION 1
C. CRITERIA FOR PROCESS SELECTION 2
D. METHOD OF ANALYSIS 5
II. FINDINGS, CONCLUSIONS AND RECOMMENDATIONS 8
A. INTEGRATED KNIT FABRIC MILL 8
B. INTEGRATED WOVEN FABRIC MILL 10
III. INDUSTRY OVERVIEW 13
A. INDUSTRY STRUCTURE 13
B. ECONOMIC OUTLOOK 17
1. Historical Trends and Projected Growth" 17
2. Total Fiber Demand and Shipments 19
3. Financial Profile 19
4. Energy Costs 24
IV. COMPARISON OF CURRENT AND ALTERNATIVE PROCESSES 25
A. BASIS FOR PROCESS SELECTION 25
1. Total Energy Use 25
2. Integrated Knit Fabric Mill 25
3. Integrated Woven Fabric Mill 27
4. Selection of Advanced Unit Operations 27
5. Advanced Processing 28
B. COMPARISON OF CURRENT AND ALTERNATIVE PROCESSES 33
1. Integrated Knit Fabric Mill 33
2. Integrated Woven Fabric Mill 44
vii
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TABLE OF CONTENTS (Cont.)
Page
V. IMPLICATIONS OF POTENTIAL PROCESS CHANGES 56
A. INTEGRATED KNIT FABRIC MILL 56
B. INTEGRATED WOVEN FABRIC MILL 57
APPENDIX A - CURRENT POLLUTION PROBLEMS AND EFFECTIVENESS OF
AVAILABLE POLLUTION CONTROL TECHNOLOGY 60
APPENDIX B - GLOSSARY 71
viii
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LIST OF FIGURES
Number Page
'III-1 U.S. Fiber Consumption - 1960-1974 with Projections to 1980 18
III-2 Fiber Consumption by Type and Product Category, 1974 and 1980 21
IV-1 Flow Diagram: Integrated Knit Fabric Mill - Base Case 34
IV-2 Flow Diagram: Integrated Knit Fabric Mill - Advanced Case 36
IV-3 Flow Diagram:'Integrated Knit Fabric Mill - Solvent Case 38
IV-4 Flow Diagram: Integrated Woven Fabric Mill - Base Case 46
IV-5 Flow Diagram: Integrated Woven Fabric Mill - Base Case 47
IV-6 Flow Diagram: Integrated Woven Fabric Mill -
Advanced Case 50
IV-7 Flow Diagram: Integrated Woven Fabric Mill -
Advanced Case 51
A-l Schematic Flow Diagram: Process Steps and Cost Centers
for Level 1 Treatment 66
A-2 Schematic Flow Diagram: Process Steps and Cost Centers
for Level II Treatment 67
ix
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LIST OF TABLES
Number Page
1-1 Summary of 1971 Energy Purchased in Selected Industry
Sectors 3
II-l Summary of Process Options in the Textile Industry 9
II-2 Integrated Knit Fabric Mill 9
II-3 Summary of Process Options in the Textile Industry 11
II-4 Integrated Woven Fabric Mill 11
III-l Number of Establishments and Number of Employees 14
III-2 Categorization Schemes for the Textile Industry 16
III-3 1974-1980 Fiber Consumption by Type, Mill Demand, and
Shipments 20
III-4 Textile Mill Products Trends, 1967-74 22
III-5 Broadwoven Fabrics, 1974 Profile 22
III-6 Knit Fabrics Mills, 1974 Profile 23
IV-1 Fuel and Electric Energy Use in the Textile Industry, 1971 26
IV-2 Energy Use in an Integrated Knit Fabric Mill 26
IV-3 Energy Use in an Integrated Woven Fabric Mill 28
IV-4 Summary of Energy Consumption: Knit Fabric Mill 40
IV-5 Capital and Operating Costs Integrated Knit Fabric Mill -
Base Case 42
IV-6 Capital and Operating Costs Integrated Knit Fabric Mill -
Advanced Case 43
IV-7 Water Pollution Control Costs for Integrated Knit Fabric Mill 44
IV-8 Capital and Operating Costs/Integrated Knit Fabric Mill -
Solvent Case 45
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LIST OF TABLES (Cont.)
Number Page
IV-9 Summary of Energy Consumption/Woven Fabric Mill 52
IV-10 Capital and Operating Costs/Integrated Woven Fabric Mill -
Base Case 53
IV-11 Capital and Operating Costs/Integrated Woven Fabric Mill -
Advanced Case 54
IV-12 Water Pollution Control Costs for Integrated Woven Fabric
Mill 55
A-l Effluent Limitations Requirements - Woven Fabric
Finishing 65
A-2 Effluent Limitations Requirements - Knit Fabric
Finishing 65
A-3 Pollution Control Costs - Woven Fabric Mill 68
A-4 Pollution Control Costs - Knit Fabric Mill 69
xi
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ACKNOWLEDGMENTS
This study could not have been accomplished without the support of a
great number of people in government agencies, industry, trade associations
and universities. Although it would be impossible to mention each individual
by name, we would like to take this opportunity to acknowledge the particular
support of a few such people.
Dr. Herbert S. Skovronek, Project Officer, was a valuable resource to us
throughout the study. He not only supplied us with information on work
presently being done in other branches of EPA and other government agencies,
but served as an indefatigable guide and critic as the study progressed. His
advisors within EPA, FEA, DOC, and NBS also provided us with insights and
perspectives valuable for the shaping of the study.
During the course of the study we also had occasion to contact many
individuals within industry and trade associations. Where appropriate we
have made reference to these contacts within the various reports. Frequently,
however, because of the study's emphasis on future developments with compara-
tive assessments of new technology, information given to us was of a confiden-
tial nature or was supplied to us with the understanding that it was not to be
credited. Therefore, we extend a general thanks to all those whose comments
were valuable to us for their interest in and contribution to this study.
Finally, because of the broad range of industries covered in this study,
we are indebted to many people within Arthur D. Little, Inc. for their parti-
cipation. Responsible for the guidance and completion of the overall study were
Mr. Henry E. Haley, Project Manager; Dr. Charles L. Kusik, Technical Director;
Mr. James I. Stevens, Environmental Coordinator; and Ms. Anne B. Littlefield,
Administrative Coordinator.
Members of the environmental team were Dr. Indrakumar L. Jashnani,
Mr. Edmund H. Dohnert and Dr. Richard Stephens (consultant).
Within the individual industry studies we would like to acknowledge the
contributions of the following people.
/
Iron and Steel: Dr. Michel R. Mounier, Principal Investigator
Dr. Krishna Parameswaran
Petroleum Refining: Mr. R. Peter Stickles, Principal Investigator
Mr. Edward Interess
Mr. Stephen A. Reber
Dr. James Kittrell (consultant)
Dr. Leigh Short (consultant)
xii
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Pulp and Paper;
Olefins:
Ammonia:
Aluminum:
Textiles:
Mr. Fred D. lannazzi, Principal Investigator
Mr. Donald B. Sparrow
Mr. Edward Myskowski (consultant)
Mr. Karl P. Fagans
Mr. G. E. Wong
Mr. Stanley E. Dale, Principal Investigator
Mr. R. Peter Stickles
Mr. J. Kevin O'Neill
Mr. George B. Hegeman
Mr. John L. Sherff, Principal Investigator
Ms. Nancy J. Cunningham
Mr. Harry W. Lambe
Mr. Richard W. Hyde, Principal Investigator
Ms. Anne B. Littlefield
Dr. Charles L. Kusik
Mr, Edward L. Pepper
Mr* Edwin L, Field
Mr, John W. Rafferty
Dr. Douglas Shooter, Principal Investigator
Mr, Robert M. Green (consultant)
Mr* Edward S, Shanley
Dr, John Willard (consultant)
Dr.. Richard F, Heitmiller
Cement:
Dr. Paul A. Huska, Principal Investigator
Ms. Anne B. Littlefield
Mr.. J.. Kevin O'Neill
Glass:
Chlor-Alkali:
Phosphorus/
Phosphoric Acid:
Primary Copper;
Fertilizers:
Dr, D, William Lee, Principal Investigator
Mr, Michael Rossetti
Mr,
Mr.
Dr, Ravindra M, Nadkarni
R. Peter Stickles
, Edward Interess
Mr, Roger E. Shamel, Principal Investigator
Mr, Harry W. Lambe
Mrs Richard P. Schneider
Mr. William V. Keary, Principal Investigator
Mr. Harry W. Lambe
Mr. George C, Sweeney
Dr, Krishna Parameswaran
Dr. Ravindra M. Nadkarni, Principal Investigator
Dr, Michel R. Mounier
Dr, Krishna Parameswaran
Mr. John L. Sherff, Principal Investigator
Mr. Roger Shamel
Dr. Indrakumar L. Jashnani
xiii
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ENGLISH-METRIC (SI) CONVERSION FACTORS
To Convert From
Acre
Atmosphere (normal)
Barrel (42 gal)
British Thermal Unit
Centipoise
Degree Fahrenheit
Degree Rankine
Foot
2
Foot /minute
Foot3
Foot2
Foot/sec
Foot2/hr
Gallon (U.S. liquid)
Horsepower (550 ft-lbf/sec)
Horsepower (electric)
Horsepower (metric)
Inch
Kilowatt-hour
Litre
Micron
Mil
Mile (U.S. statute)
Poise
Pound force (avdp)
Pound mass (avdp)
Ton (assay)
Ton (long)
Ton (metric)
Ton (short)
Tonne
To
Metre2
Pascal
Metre3
Joule
Pascal-second
Degree Celsius
Degree Kelvin
Metre
Metre /sec
Metre3
2
Metre
Metre/sec
2
Metre /sec
Metre3
Watt
Watt
Watt
Metre
Joule
Metre3
Metre
Metre
Metre
Pascal-second
Newton
Kilogram
Kilogram
Kilogram
Kilogram
Kilogram
Kilogram
Multiply By
4,046
101,325
0.1589
1,055
0.001
t' = (tj -32)/1.8
t° - t°/1.8
0.3048
0.0004719
0.02831
0.09290
0.3048
0.00002580
0.003785
745.7
746.0
735.5
0.02540
3.60 x 106
1.000 x 10~3
1.000 x 10"6
0.00002540
1,609
0.1000
4.448
0.4536
0.02916
1,016
1,000
907.1
1,000
Source: American National Standards Institute, "Standard Metric Practice
Guide," March 15, 1973. (ANS72101-1973) (ASTM Designation E380-72)
xiv
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I. INTRODUCTION
A. BACKGROUND
Industry in the United States purchases about 27 quads* annually, approxi-
mately 40% of total national energy usage.** This energy is used for chemical
processing, raising steam, drying, space cooling and heating, process stream
heating, and miscellaneous other purposes.
In many industrial sectors energy consumption can be reduced significantly
by better "housekeeping" (i.e., shutting off of standby furnaces, better thermo-
stat control, elimination of steam and heat leaks, etc.) and greater emphasis
on optimization of energy usage. Iri addition, however, industry can be expected
to introduce new industrial practices or processes either to conserve energy
or to take advantage of a more readily available or less costly fuel. Such
changes in industrial practices may result in changes in air, water of solid
waste discharges. The EPA is interested in identifying the pollution loads of
such new energy-conserving industrial practices or processes and in deter-
mining where additional research, development, or demonstration is needed to
characterize and control the effluent streams.
B. CRITERIA FOR INDUSTRY SELECTION
In the first phase of this study we identified industry sectors that have
a potential for change, emphasizing those changes which have an environmental/
energy impact.
Industries were eliminated from further consideration within this assign-
ment if the only changes that could be envisioned were:
energy conservation as a result of better policing or "housekeeping,"
better waste heat utilization,
fuel switching in steam raising, or
power generation.
*1 quad = 1015 Btu
**Purchased electricity valued at approximate fossil fuel equivalence of
10,500 Btu/kWh.
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After discussions with the EPA Project Officer and his advisors, indus-
try sectors were selected for further consideration and ranked using:
Quantitative criteria based on the gross amount of energy (fossil
fuel and electric) purchased by industry sector as found in U.S.
Census figures and from information provided from industry sources.
The textile industry purchased 0.54 quads out of the 12.14 quads
purchased in 1971 by the 13 industries selected for study, or 2% of
the 27 quads purchased by all industry (see Table 1-1).
Qualitative criteria relating to probability and potential for
process change, and the energy and effluent consequences of such
changes.
In order to allow for as broad a coverage of technologies as possible, we
then reviewed the ranking, eliminating some industries in which the process
changes to be studied were similar to those in another industry planned for
study. We believe the final ranking resulting from these considerations identi-
fies those industry sectors which show the greatest possibility of energy con-
servation via process change. Further details on this selection process can be
found in the Industry Priority Report prepared under this contract (Volume II).
On the basis of this ranking method, the textile industry appeared in ninth
place among the 13 industrial sectors listed. Of the 0.54 quads of energy
purchased by the textile industry in 1971, about 48% was for electrical energy
and the remaining 52% was supplied by distillate and residual fuel oil, natural
gas, propane, and coal. Dyeing and finishing operations consume about 60%
of all the energy used in producing textiles, relying heavily on steam for
water heating and on propane and natural gas for drying and heat setting.
The other processes, such as spinning, weaving, and knitting, consume the
remaining energy, primarily in the form of electricity for motor power.
Demand for energy in the textile industry is expected to increase in line
with population growth and consumer demands.
Much of the.energy required is used for heating water for dyeing fiber
or fabric and for subsequent washing and drying and heat setting operations.
Therefore, process changes which reduce or eliminate water use will have a
major positive impact on energy conservation. Major process changes either
under development or already in limited use commercially which satisfy
these goals are identified in the next section.
C. CRITERIA FOR PROCESS SELECTION
In this study we have focused on identifying changes in the primary
production processes which have clearly defined pollution consequences.
In selecting those to be included in this study, we have considered the
needs and limitations of the EPA as discussed more completely in the Indus-
try Priority Report mentioned above. Specifically, energy conservation has
been defined broadly to include, in addition to process changes, conserva-
tion of energy or energy form (gas, oil, coal) by a process or feedstock
change. Natural gas has been considered as having the highest energy form
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TABLE 1-1
SUMMARY OF 1971 ENERGY PURCHASED IN SELECTED INDUSTRY SECTORS
SIC Code
.. In Which
Industry Sector 10 Btu/Yr Industry Found
i. Blase furnaces and sceel mills 3.49(1) 3312
2. Petroleum refining 2.96<2) 2911
3 Paper and allied products 1.59 26
4. Oleflns 0.984<3) 2818
5 Ammonia 0.63<4) 287
6 Aluminum 0.59 3334
7 Textiles 0.54 22
8. Cement 0.52 3241
9 Glass 0.31 3211, 3221, 3229
10. Alkalies and chlorine 0.24 2812
11. Phosphorus and phosphoric ...
acid production 0.12°' 2819
12. Primary copper 0.081 3331
13. Fertilizers (excluding ammonia) 0.078 287
Estimate for 1967 rep
USCPO, November 1974.
Includes captive consumption of energy from process byproducts (FEA Project
Independence Blueprint)
Olefins only, Includes energy of feedstocks: ADL estimates
(4)
Ammonia feedstock energy Included: ADL estimates
<5)ADL estimates
Source: 1972 Census of Manufactures, FEA Project Independence Blueprint, USCPO,
November 1974, and ADL estimates.
value followed in descending order by oil, electric power, and coal. Thus, a
switch from gas to electric power would be considered energy conservation
because electric power could be generated from coal, existing in abundant
reserves in the United States in comparison to natural gas. Moreover, pollu-
tion control methods resulting in energy conservation have been included
within the scope of this study. Finally, emphasis has been placed on pro-
cess changes with near-term rather than long-term potential within the 15-year
span of time of this study.
In addition to excluding from consideration better waste heat utiliza-
tion, "housekeeping," power generation, and fuel switching, as mentioned
above, certain options have been excluded to avoid duplicating work being
funded under other contracts and to focus this study more strictly on "pro-
cess changes." Consequently, the following have also not been considered to
be within the scope of work:
Carbon monoxide boilers (however, unique process vent streams
yielding recoverable energy could be mentioned);
Fuel substitution in fired process heaters;
Mining and milling, agriculture, and animal husbandry;
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Substituion of scrap (such as reclaimed textile, iron, aluminum,
glass, and paper) for virgin materials;
Production of synthetic fuels from coal (low- and high-Btu gas,
synthetic crude, synthetic fuel oil, etc.); and
All aspects of industry-related transportation (such as transpor-
tation of raw material).
A major difficulty arises in identifying suitable process options in the
textile industry because of the complexity and diversity of textile processing.
Textile mills consist of a series of unit operations linked together in a
variety of ways and producing many different end products. It is difficult
to find two mills which use exactly the same processing sequence and in fact,
most mills vary their processing to meet market demands. Consequently, a
variety of natural and synthetic fibers are processed singly and in combina-
tion. The type and proportion vary from mill to mill and with season, to
meet product requirements.
There are many potential "energy conserving" unit operations being
introduced commercially or under development, some with EPA sponsorship.
Any given unit operation will not by itself make a substantial impact on
the textile industry but a series of such operations assembled in a textile
mill can make a substantial impact. However, the number of possible com-
binations is too large and must somehow be reduced to a manageable number.
After discussion with the EPA Project Officer, his advisors, and industry
representatives, we have chosen to overcome this problem by defining "model"
textile mills which would maximize the use of energy conserving "unit pro-
cess" options. In addition, water consumption is the most important con-
tributor to energy costs and indirectly to environmental problems. Therefore,
"advanced" processing techniques (including dry processing) which reduce
water use, or solvent processing techniques are expected to have the greatest
impact on energy conservation. ~
Using these guidelines the following models were defined.
1. Integrated knit fabric mill* using "advanced" processing of 100%
polyester fiber.
2. Integrated knit fabric mill using solvent processing of 100%
polyester fiber.
3. Integrated woven fabric mill using advanced processing of 50/50
polyester/cotton fiber mixture.
*A glossary of textile terms is included in Appendix B of this report.
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The environmental, energy and economic impacts of these "model" technolo-
gies can then be compared to "base line" technology which represents the
best of present textile industry practice. Knitting and weaving are the
two principal processes used in the textile industry. Polyester knit goods
and polyester/cotton woven goods represent the most important types of fiber
used in these operations. Thus, the models are applicable to major segments
of the textile industry but conversely, do not consider directly other impor-
tant segments of the industry (carpets, yarns), different synthetic and
natural fiber use (nylon, acrylics, wool), or the effects of the many dif-
ferent end products.
However, we believe that the principles evolved are applicable to other
sections of the textile industry, particularly with respect to "advanced"
processing. We have more reservations with respect to solvent processing,
which has only found real application to certain process operations for knit
goods and further technical development is required before wide-spread appli-
cation of solvent processing can occur. It was originally intended to study
solvent processing of woven fabric, but during the course of the study it
became apparent that data was not available to develop a model mill based on
solvent processing of polyester/cotton fiber.
D. METHOD OF ANALYSIS
Within each industry, the magnitude of energy use was an important cri-
terion in judging where the most significant energy savings might be realized,
since reduction in energy use reduces the amount of pollution generated in
the energy production step. Guided by this consideration, candidate options
for in-depth analysis were identified from the major energy consuming steps
with known or potential environmental problems.
After developing a list of candidate process options, we assessed
subj ectively
pollution or environmental consequences of the process change,
probability or potential for the change, and
energy conservation consequences of the change.
Even though all of the candidate process options were large energy
users, there was wide variation in energy use and estimated pollution loads
between options at the top and bottom of the list. A modest process change
in a major energy consuming process step could have more dramatic consequences
than a more technically significant process change in a process step whose
energy consumption is rather modest. For the lesser energy-using process
steps process options were selected for in-depth analysis only if a high
probability for process change and pollution consequences were perceived.
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Because of the time and scope limitations for this study, we have not
attempted to prepare a comprehensive list.of process options or to consider
all economic, technological, institutional, legal or other factors affecting
implementation of these changes. Instead we have relied on our own back-
ground experience, industry contacts, and the guidance of the Project Officer
and EPA advisors to select reasonably promising process options (with an
emphasis on near-term potential).
In this study, the textile industry description is based on 1972, the
latest representative year for the industry for which we had good statisti-
cal information. Recognizing that capital investments and energy costs have
escalated rapidly in the past few years and have greatly distorted the tra-
ditional basis for making cost comparisons, we developed costs representative
of the first half of 1975, using constant 1975 dollars for our comparative
analysis of new and current processes.
The procedure adopted for this project was to construct a base case
analysis for both a representatively sized integrated mill producing knit
fabric and one producing woven fabric in the following manner.
First, we devised an appropriate series of unit operations to produce
the textile fabric, and then proceeded to construct the mass and energy
balances around each unit operation in the process. This was then sum-
marized in tabular form to obtain an overall mass and energy balance for
the process. From the mass balances we also determined pollution loadings
for effluent streams to be discharged to air and water. (Solid waste is a
minor problem in this industry.)
Second, we constructed cost analyses showing both operating and capital
costs in a predetermined format, using appropriate factors to describe the
textile industry (e.g., labor rates, overhead factors, depreciation, raw
material use, and fuel and utilities consumption).
This model, base line mill so constructed, is not intended to relate to
any given textile operation. However, we believe it is probably more repre-
sentative of a combination of the best technology practiced in existing
mills, rather than the average technology presently achieved in the textile
industry.
Following this part of the analysis, we then applied a similar method-
ology to construct process option examples using energy conserving tech-
nology. Since a major part of the energy consumption occurs from heating
and vaporization_of_water, those process options which reduce water con-
sumption or eliminate water use (dry processing or solvent processing)
deserve first consideration. Separate models have been constructed for
"advanced" processing (i.e., combination of process options with reduced water
use) and solvent processing (no water use). Dry processing unit operations
fit into either category. A solvent processing example for woven fabric was
.not constructed because appropriate data was not available.
-------
These model process options use essentially the same sequence of unit
operations but we have substituted the latest textile equipment, introduced
recycle loops for resource recovery where applicable, and reduced water and
energy use in accordance with the expected performance represented by this
new technology. In some cases, the substitution of the new equipment allowed
elimination of certain energy consuming process operations.
The data for these models was based on information obtained from the
literature, from equipment manufacturers, from textile industry manufacturers,
and other industry contacts. It also relies on information obtained from
various EPA publications, such as the Effluent Guidelines Document and the
Economic Analysis of Effluent Guidelines, together with information obtained
from other published analyses of the textile industry. (These source are
identified at the appropriate places.)
-------
II. FINDINGS, CONCLUSIONS AND RECOMMENDATIONS
A. INTEGRATED KNIT FABRIC MILL
A summary of the conclusions for advanced processing and solvent process-
ing is provided in Table II-l. A comparison in terms of economic, energy and
environmental considerations with the base line is shown in Table II-2. Overall
energy use is decreased by 50% with advanced processing, although electricity
use is increased through substitution of air extraction for conventional dry-
ing. The same substitution, together with more efficient operation of the heat-
set tenterframes* reduces natural gas use considerably. Reduction in steam
use is achieved through maximum water economy and by recycling rinsewaters.
Solvent processing shows a 70% reduction in overall energy use, although
steam is still required for evaporation and recovery of the solvent and for
stripping the solvent after the finishing operation.
Advanced processing does not reduce the pollution loading (because the
same chemicals are used), but the lower hydraulic load should reduce pollution
control costs and reduce the total quantities of pollutants emitted. All-
solvent processing practically eliminates the water pollution potential, but
the chemicals removed from the solvent present a solid-waste disposal problem.
Solvent recovery must be very high for economic reasons, but solvent losses may
still represent an air pollution problem. Solvent recovery systems are designed
by the manufacturers to meet present air pollution control regulations and
environmental health regulations, but there is considerable concern on the part
of EPA and OSHA that chlorinated solvents are a particular hazard that may
require more severe regulation. This factor may be a potential deterrent to
the adoption 'of solvent processing, although at the present time the technical
limitations are probably more important. The capital investment required for
the advanced process options is not a great deal higher than for conventional
technology;** therefore, this would not be the determining factor in introducing
technology to a new plant or processing line. However, because of the small
leverage of energy costs compared to capital costs, there is no major advantage
in terms of reduced product costs that might encourage the adoption of such
*A1though waste heat recovery per se is outside the scope of this study, we
have included as a process modification a heat recovery unit attached directly
to the tenterframe which preheats the incoming air.
**Differences in the capital investment estimates, shown in Table II-2, are with-
in the accuracy of the analysis (±20%), but from a knowledge of equipment costs
we conclude that a small, real difference does exist.
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TABLE II-l
SUMMARY OF PROCESS OPTIONS IN THE TEXTILE INDUSTRY
(Base line process: Integrated Knit Fabric Mill)
Process Options
Advanced Processing Solvent Processing
ECONOMICS Slightly higher capital cost. Higher capital cost, lower
Marginally lower pollution con- operating cost, lower energy
trol costs as a result of costs, (pollution control is an
reduced process water consump- integral part of the solvent
tion. Lower energy costs. recovery system).
ENERGY Lower steam and natural gas Lower natural gas use, but
use. Higher electrical energy higher steam consumption for
use through substitution of solvent recovery. Overall
mechanical energy for heat decrease of 70% in energy use.
energy to remove water. Overall
energy saving of 50%.
ENVIRONMENTAL No change in feedstock or pro- No change in feedstock or pro-
ducts. Lower water use allows ducts. Eliminates water pollu-
more effective biological waste- tion problems but introduces
water treatment. Minimal air potential air pollution from
pollution, no solid waste. chlorinated hydrocarbons. Some
solid waste for disposal but
lower overall chemical use.
TABLE II-2
INTEGRATED KNIT FABRIC MILL
(Production: 22,000 Ib/day)
Base Line Advanced Solvent
Process Process Process
(thousand Ib) (thousand Ib) (thousand Ib)
ENERGY CONSUMPTION
Electricity (106 Btu equiv.) 1.9 2.6 1.3
Steam (106 Btu equiv.) 8.2 4.1 2.4
Natural Gas (106 Btu) 4.0 0-4 0.4
Total (106 Btu) 14.1 7.1 4.1
POLLUTION POTENTIAL
WATER
Hydraulic Load gal 6,190 2,050
Pollution Loading (BOD Ib) 25 25
(COD Ib) 80 80
(TSS Ib) 80 80
AIR Small Small . Small
SOLID WASTE Small (~100 Ib)
ECONOMICS
Capital Investment ($) 2,560 2,650 2,820
Variable Costs ($) 1,620 1,610 1,500
Fixed Costs (?) 420 430 450
Energy Costs ($) 26 13 21
Pollution Control Costs ($) 26 16 *
Total Annual Costs ($) 2,450 2,440 2,330
Notes: Electricity 1 kUh - 10,500 Btu equiv.
Variable costs include energy costs.
Total Annual Costs = (Fixed Costs + Variable Costs + Pollution Control
Costs) x 12.
Energy consumption from Table IV-5.
Economics from Table IV-6, IV-7, IV-9.
*Pollution control costs are Included in manufacturing costs.
-------
technology at a rapid rate throughout the industry. The incremental capital
costs for advanced processing over the base line are adequately repaid from
reductions in operating costs and pollution control costs. Therefore, whenever
new or replacement capacity is required, advanced processing does have an eco-
nomic (and environmental) advantage. It also has lower energy costs, thus pro-
viding the manufacturer with some protection against future fuel and energy
price increases. It is also feasible for the unit operations which make up the
advanced processing to be adopted piecemeal by existing plants, with a conse-
quent energy saving and lowering of pollution control costs.
Similar comments apply to the solvent processing system, but there are
other reservations. Equipment for solvent processing is commercially available
and being used in textile mills, generally in more specialized applications
where solvent processing is essential because of the nature of the chemicals
used or because an improved product is obtained. At present, the most widespread
application is in scouring of knit goods. An all-solvent processing line would
have the advantage of completely eliminating wastewater effluent, but as yet,
the technology is not sufficiently well demonstrated to show that an all-solvent
processing line is commercially feasible. The dyeing step is particularly trouble-
some; in spite of much work, there are still severe limitations in the type of
dyes and range of colors that can be applied from a solvent medium. In particu-
lar, the dyeing of polyester by solvent methods has not been adequately demonstra-
ted and this is one of the most important fibers being used in knit fabric today.
B. INTEGRATED WOVEN FABRIC MILL
A summary of conclusions concerning advanced processing for woven fabrics
is given in Table II-3. A comparison of energy consumption, pollution poten-
tial, and economics is given in Table II-4. Advanced processing offers a 57%
reduction in energy consumption from a reduction in electricity, steam, and
natural gas use. Reduced electricity and steam consumption is a result of
better water economy (in spite of the increased electrical requirements for
PVA recovery). Lower natural gas use comes from optimization of tenterframe
operations for drying and heat setting, which includes the addition of a heat
recovery unit on each tenterframe. This reduction is a result of optimization
of 23 different unit operations in a particular sequence for the processing of
a 50/50 polyester/cotton fabric. Many textile mills have much more diversified
processing, so the energy savings may be less, but we would still expect them
to be substantial.
It is assumed that the wastewater effluent from base line and advanced
processing are both treated by biological methods. As with the knit fabric
mill, the decreased hydraulic load will reduce treatment plant size and costs.
PVA size recovery reduces the hydraulic load and the pollution loading (BOD
and COD). Potential air and solid waste effluents are minor. Some organics
(degradation products of finishing chemicals) escapes with the flue gas, but
with good operation the levels of hydrocarbon are below the levels set by
regulation. Other minor amounts of finishing chemicals may end up as a tarry
residue in the tenterframe which is periodically removed for disposal.
Adoption of advanced processing does not greatly reduce product cost
because of the high capital investment required for a new woven mill. The
10
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TABLE II-3
SUMMARY OF PROCESS OPTIONS IN THE TEXTILE INDUSTRY
(Base line process: Integrated Woven Fabric Mill)
Advanced Processing
ECONOMICS Slightly higher capital cost. Slightly lower
operating cost. Lower pollution control costs
through water conservation and resource
recovery.
ENERGY Lower energy use (Natural gas, steam, and elec-
tricity) through reduction in process water
consumption and through, resource recovery.
Overall energy saving of 57%.
ENVIRONMENTAL No change in feedstock or product. Lower pol-
lution loading (from PVA recovery) and lower
water use allows more effective biological
wastewater treatment. Minimal air pollution,
no solid waste.
TABLE II-4
INTEGRATED WOVEN FABRIC MILL
(Production 66,000 Ib/day)
Basis: 1000 Ib of production
ENERGY CONSUMPTION
Electricity (106 Btu equiv.) 3.0 1.6
Steam (106 Btu equlv.) 32.2 14.4
Natural gas (106 Btu) 7.1 2.2.
Total (106 Btu) 42.3 18.2
POLLUTION POTENTIAL
WATER
Hydraulic Load gal 16,800 5,830
Pollution Loading (BOD Ib) 30 25
(COD Ib) 100 50
(TSS Ibj) 100 100
AIR Small Small
SOLID WASTE Small Small
ECONOMICS
Capital Investment ($) 5,610 5,690
Variable Costs ($) 1,480 1,400
Fixed Costs ($) 860 860
Energy Costs ($) 81 33
Pollution Control Costs ($) 20 18
Total Annual Cost ($) 2,810 2,720
Notes: Electricity 1 kWh = 10,500 Btu equiv.
Variable Costs include energy costs.
Total Annual Costs - (Fixed Costs + Variable Costs + Pollution Control
Costs) x 1.2.
Energy consumption from Table IV-10.
Economics from Tables 1V-11, IV-12.
11
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incremental costs of capital investment for advanced processing over conven-
tional processing in a new mill are relatively small and show a good payback
in terms of lower energy use and resource recovery. Lower pollution loading
from PVA recovery and reduced water use will also reduce the size and cost of
biological treatment plants for the wastewater effluent. Therefore, adoption
of advanced processing appears likely for capacity replacement and expansion.
PVA recovery is attractive economically and environmentally, and will be used
if it can be shown to be applicable to a wider range of fiber combinations.
C. RECOMMENDATIONS FOR FURTHER RESEARCH
PVA recovery has been shown to have economic and energy-conserving
advantages. So far, however, this has only been demonstrated on
polyester/cotton sheeting. Its applicability to other products and
fibers should be demonstrated.
Energy saving is possible if the amount of water used for washing
can be reduced substantially. This requires an evaluation of washing
efficiency for the various types of washers currently used in the
industry and for the new units now available. Concurrent with this,
there should be a program to demonstrate improved instrumentation
and techniques for monitoring washing in the various process steps
and to determine when adequate washing has been achieved.
Water reuse currently appears to be limited by the variety of chemi-
cals used in each process step. Development work could minimize the
amount of chemical used in each step and make the different chemicals
more compatible with each other, so that processing steps might be
combined and/or additional water recycled.
Recovery of chemicals other than PVA and caustic soda has not yet
achieved any major application, although work is in progress to eval-
uate water and chemicals reuse in dyeing operations. (EPA 800929 and
Brandon, 1975). Additional methods for recovery of dyes - high-cost
chemicals that cause color problems in waste treatment plants because
of their refractory nature-should be investigated.
A major obstacle to the demonstration of an all-solvent processing
system is thr lack of acceptable techniques for solvent dyeing, par-
ticularly of polyester and cotton/polyester blends. Pilot-scale
studies should be carried out to demonstrate the advantages and limi-
tations of the best processes described in the literature. Similar
work is also required to demonstrate the applicability of solvent
finishing systems.
It appears from the data available that solvent losses from an all-
solvent system are now only marginally acceptable and may be in excess
of future occupational health or environmental regulations. A study of
an all-solvent system is required to define where and how solvent
losses occur and to develop better control technology for solvent
emissions. Otherwise, we believe this problem may represent an obsta-
cle to further development of solvent processing.
12
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III. INDUSTRY OVERVIEW
A. INDUSTRY STRUCTURE
The textile industry is extremely diversified, processing a variety of
fabrics and fabric blends into a multitude of end products. Its primary
customer is the domestic apparel industry,* followed by the auto and furni-
ture industries. Knit apparel, yarns and carpets are also produced as final
products for the consumer. Textile plants range from highly integrated manu-
facturing complexes that process fibers (natural and synthetic) into finished
products, to small, non-integrated contract plants (commission finishers) that
process goods owned by dther producers.
According to the standard SIC Classification (Census of Manufactures,
1972), the textile industry contains 10 major SIC classifications and 30 sub-
classifications. A breakdown according to these classifications, in terms
of the number of establishments and number of employees, is listed in Table
III-l. The total number of plants listed (7,203), is distributed over 47
states, and has increased only about 2% since the 1967 census. However,
there have been changes within the groupings that reflect internal changes
within the textile industry, such as the decline in weaving mills for cotton (SIC
.221) and wool (223), together with increases for knitting mills (225) and
floor-covering mills (227). Knitting mills now constitute the largest single
SIC group, with 2,723 plants, followed by weaving mills of various types
totaling 1,293 plants. These two categories together provide 56% of the total
number of plants and an even higher proportion of total production.
The textile industry is labor intensive(Department of Commerce, 1974, 1975),
accounting for about 5% of the U.S. manufacturing workforce. Employment was
about 960,000 in 1972 and peaked at over one million in 1973. By mid-1975,
employment was down to 910,000 causing the unemployment rate in the industry
to remain above the average for all manufacturing throughout 1975. As shown
in Table III-l, weaving mills and knitting mills constitute 62% of the total
employment.
In recent decades, the industry has been concentrating in the Southeast -
notably in North and South Carolina, Georgia, and Alabama - and this trend is
*The apparel industry (SIC 23) consists of establishments that cut and sew
clothing (knits and wovens, outerwear and underwear) from purchased fabric.
13
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TABLE III-l
NUMBER OF ESTABLISHMENTS AND NUMBER OF EMPLOYEES
SIC
CODE
2211
2221
2231
2241
Total
2251
2252
2253
2254
2257
2258
2259
Total
2261
2262
2269
Total
2271
2272
2279
Total
2281
2282
2283
2284
Total
2291
2292
2293
2294
2295
2296
2297
2298
2299
Total
22
Source:
NAME
NUMBER OF
ESTABLISHMENTS
THOUSANDS OF
EMPLOYEES
Weaving Mills - Cotton
Weaving Mills - Manmade fiber
Weaving and Finishing Mills - Wool
Narrow Fabric Mills
Weaving Mills
Women's Hosiery
Hosiery NEC
Knit Outerwear Mills
Knit Underwear Mills
Circular Knit Fabric Mills
Warp Knit Fabric Mills
Knitting Mills NEC
Knitting Mills
Finishing Plants - Cotton
Finishing Plants - Manmade fiber
Finishing Plants NEC
Dyeing and Finishing Textiles
(except wool fabrics & knit goods)
Woven Carpets & Rugs
Tufted Carpets & Rugs
Carpets & Rugs NEC
Floor Covering Mills
Yarn Mills, except wool
Throwing and Winding Mills
Wool Yarn Mills
Thread Mills
Yarn & Thread Mills
Felt Goods
Lace Goods
Padding & Upholstery Filling
Processed Textile Waste
Coated Fabrics
Tire Cord & Fabric
Non-Woven Fabrics
Cordage & Twine
Textile Goods NEC
Miscellaneous Textile Goods
Total Textile Goods
1972 Census of Manufactures
196
259
201
64
381
83
47
105
132
106
202
18
82
156
34?
1,293
2,723
656
528
810
1,193
7,203
121,
149.
19,
27,
49.5
32.6
74.4
26.0
68.0
22.0
3.9
6.5
50.3
3.1
89.7
38.0
8.5
5.0
2.9
4.4
3.6
17.9
10.0
10.4
9.0
317.5
276.4
79.7
66.4
147.8
71.5
959.3
14
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continuing. Today, nearly 40% of the textile plants are in the Southeast
and over 90% are on the Eastern Seaboard. The rest are scattered thinly
throughout the United States.
The industry's basic raw materials are wool, cotton, and manmade fibers.
Wool now accounts for a very small proportion of the industry, and that pro-
portion is declining. Cotton is still a major raw material, but shows very
little growth; whereas the use of manmade fibers* is growing quite rapidly.
The natural fibers are supplied in staple form (short fibers). Manmade
fibers are supplied as either staple or continuous filament. In either case,
fiber is spun into yarn, which is simply a number of filaments twisted
together. The yarn is woven or knit into a fabric, and the fabric is then
dyed and treated to impart such characteristics as shrink resistance, crease
resistance, etc. The finished fabric is delivered directly or through
converters, jobbers, and wholesalers to the manufacturer of textile
products.
In transforming a fiber, both wet and dry processes are used. The SIC
code breakdown is not particularly useful for evaluating the waste problems
of the textile industry. The codes are grouped primarily by the process
used e.g., weaving or knitting, which are essentially dry processes
whereas waste problems stem from various wet processes that are used (sizing,
desizing, washing, dyeing, scouring, mercerizing, bleaching, and various
types of finishing processes). SIC Code 226 identifies textile finishing,
Code 221 identifies weaving mills, which may also be integrated mills that
have a finishing operation or may be greige** goods mills that have only dry
processing. Knitting mills fall into a similar category; many of the mills
identified as knitting mills, in fact, process dyed yarns and, therefore,
essentially carry out only dry operations.
To surmount this difficulty and assist in promulgation of effluent
guideline limitations, the EPA divided the textile industry into 7 categories,
as shown in Table III-2. All the dry plants are essentially lumped together
into Category 3, greige goods. Similar categorizations, but with more sub-
divisions, have been proposed by others (see Table III-2), but they do not
overcome the problem, which is that all the statistical data (energy, econom-
ics, etc.) is arranged by SIC code and cannot be directly correlated with
effluent data. This makes it very difficult to establish the effects on the
industry of a process change at the plant level. A further obstacle to
deriving industry data is the lack of a good estimate, on the number of "wet"
plants (plants using wet-process operations) or total water use by the indus-
try. The Census of Manufactures for 1968 listed a total of 684 wet plants
*Principal manmade fibers are: rayon, acetate, nylon, acrylic, polyester,
polypropylene, and glass fiber.
**See Appendix B "Glossary".
15
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TABLE III-2
CATEGORIZATION SCHEMES FOR THE TEXTILE INDUSTRY
Environmental Protection Agency
1. Wool Scouring
2. Wool Finishing
3. Greige Goods Mill
4. Woven Fabric Finishing
5. Knit Fabric Finishing
6. Carpet Mill
7. Stock & Yarn, Dyeing and
Finishing
American Textile Manufacturers
Institute *
1. Wool Scouring
2. Wool Finishing
3. Greige"Mill
4. Woven Fabric Finishing
5. Knit Fabric Finishing
6. Greige Mill & Woven Fabric
Finishing
7. Carpet Backing & Foam
8. Integrated Carpet Mill
9. Stock & Yarn Dyeing & Finishing
10. Greige Mill & Finishing of Yarns
& Knit Fabrics
11. Combined Materials
Finishing - Stock, Yarn
Wovens, Knits
12. Multiple Operation, Commission
House
National Commission on Water
Quality (Lockwood Greene)^
1. Wool and Animal Hair Scouring
2. Wool Raw Stock, Top & Yarn Dyeing
3. Wool and Animal Hair Fabric
Finishing
4. Woven Dry Processing Mill
5. Adhesive Related Dry Processing Mill
6. Woven Fabric Finishing, Cotton &
Blends
7. Woven Fabric Finishing, Others
8. Knit Fabric Finishing, Cotton and
Blends
9. Knit Fabric Finishing, 100% Synthetic
10. Piece Dyeing and Printing of Carpets,
Wool, Cotton and Synthetics
11. Stock & Yarn Dyeing of Cotton and
Synthetic Yarns
13. Specialized Finishing
1 Report by the Institute of Textile Technology and Hydcoscience Inc., Jan. 15, 1973
2 Draft Report-by Lockwood Greene No. 74391-01, March 10, 1975
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which consume 109 billion gallons of process water per year. 1970 estimates
by the American Textile Manufacturers Institute (Institute of Textile
Technology and Hydroscience, Inc., 1973) gave 346 plants using 104 billion
gallons per year (estimated to be 83% of total industry use).
Lockwood Greene (Lockwood Greene Engineers, Inc., 1975) conducted an
extensive survey of the textile industry in 1973, and identified 1,926 wet
operations and 1,852 dry operations out of 5,366 mills. From an employee
count, Greene estimated that less than 12% of the industry data was missing
from the wet operation category. From this array of data, we estimate' that
present water use by the textile industry is in the range of 100-125 billion
gallons/yr. About 2000 mills have wet operations of some kind, and 75-85%
of the water use is concentrated in 300-350 relatively large plants.
B. ECONOMIC OUTLOOK
1. Historical Trends and Projected Growth
The U.S. textile industry has experienced modest growth since 1960
(Department of Commerce 1974, 1975). Total fiber consumed by the industry
for manufacture into textile products increased by 85.5%, from 6.4 billion
pounds in 1960 to 11.5 billion pounds in 1973. During the 1974-75 recession,
fiber consumption fell to a 10 billion pounds annual rate, but is now recov-
ering. As another indicator of the effects of the recession, the Federal
Reserve Industrial Production Index for Textile Mill Products was 125.5
(1967 = 100) in the first half of 1974, compared with 126.8 for the first
half of 1973. By February 1975, the Index was 93.3, the lowest point in
almost 10 years, and 27% below the previous year. We project that by 1980
(Figure III-l), annual fiber consumption will reach 13.4 billion pounds,
(16.5% above the peak year of 1973).
Synthetic fibers (polyester, nylon, acrylic and olefin fibers) drama-
tically increased their market share from 10% of total fiber consumption in
1960 to about 60% of total fiber consumption in 1973. Demand for these
fibers will continue to grow and is expected to be approximately 70% (9.4
billion pounds) of total fiber consumption by 1980. U.S. capacity for pro-
duction of these synthetic fibers is scheduled to increase at a rate suffi-
cient to accommodate this growth, even with potential feedstock shortages.
The rapid demand growth fo'r polyester fiber after 1968 was accomplished
by continued penetration into traditional cotton markets, especially in home
furnishing (e.g., sheets) and woven apparel (e.g., shirting), but more par-
ticularly by the emergence of the textured, continuous-filament, knit-fabric
industry which utilizes predominantly polyester fiber. During this period,
the manmade cellulosic fibers (rayon and acetate) and natural fibers (cotton
and wool) have gradually lost ground to polyester, unable even to hold
historical market volumes.
17
-------
00-
13
12
10
LLJ
z
2
8
._!
DQ
I
O
t 6
uj 4
OQ
TOTAL FIBER
MAN-MADE CELLULOSICS
COTTON
YEAR
60 62 64 66 68 70 72 74 76 78
Figure III-l. U.S. Fiber Consumption - 1960-1974 with Projections to 1980
80
-------
In the late 1970's, we expect a continued slow decline in cotton and
wool consumption, while manmade cellulosics will probably hold their own in
total output. Cotton fiber will suffer increasingly in competition with
polyester, thus increasing the proportion of blended fabrics. The 1980 ship-
ments of manmade fibers are expected to increase over 1974 shipments by 80%
for polyester, 37% for nylon, 27% for acrylics and modacrylics, and 56% for
polypropylene.
2. Total Fiber Demand and Shipments
A breakdown of fiber consumption in U.S. markets is shown in Table III-3,
where mill consumption is adjusted with estimated imports and exports to pro-
vide total shipments by fiber type.
The U.S. textile industry had suffered from sharply rising imports for a
decade until the situation reversed in 1973. This reversal was independent
of import quotas imposed in the early 1970's and was due to sharply increased
fiber and manufacturing costs in Europe and much of the Far East and relative
changes in international monetary policy. Imports have undergone a sharp
decline (not even meeting the imposed quotas) and exports have increased very
substantially to more than offset imports. Exports exceeded imports, 663 to
461 million pounds, in 1974. We expect this trend to continue. A net
balance of 2% exports in total shipments should increase to 3% in 1980.
Cotton containing manufactured products will continue to be the largest single
factor in both imports and exports.
U.S. production for domestic markets is shown in Figure III-2 by fiber
type for apparel, home furnishings, and industrial and miscellaneous fabric
in 1974, together with estimates for 1980. Home-furnishing fabrics are
expected to show the greatest growth, increasing market share by 1980 from
30% to 35%. This growth will involve primarily increased usage of polyester
and nylon. Cotton fiber is expected to hold its own in apparel and home
furnishing markets (with growth going to synthetic fibers), but will suffer
losses in industrial fabrics, particularly to polyester. Wool is expected
to continue to lose ground in all three principal application areas.
3. Financial Profile
Trends for textile mill products are shown in Table III-4. Over the
period from 1967 to 1974, the value of shipments has increased from slightly
under $20 billion to over $33 billion. Broad woven fabrics suffered a 27%
drop in production in the first half of 1975, but still maintain a dominant
position in the industry. A profile of broad woven fabric production for
1974 is shown in Table III-5. Fabric shipments in 1974 were $8 billion out
of the industry's total of $33 billion, and employment represented about 30%
of the textile workforce. A profile of knit fabrics for 1974 is given in
Table III-6. Production was down in 1975 for most knit fabrics, but double-
knits and tricot did well. ' Knit-fabric mills produced 13% of textile
industry shipments and employ about 10% of the workforce.
19
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TABLE III-3
1974 - 1980 FIBER CONSUMPTION BY TYPE, MILL DEMAND, AND SHIPMENTS
(Millions of Pounds)
Mill Demand
Polyester
Filament
Staple
Nylon
Filament
Staple
Aery lie /Modacry lie
Polypropylene
Acetate/Triacetate
Rayon Staple
Cotton
Wool
1974
1320
1370
1401
495
614
150
315
562
3242
148
1980
2555
2680
1830
805
776
235
270
628
3100
100
Imports
1974
72
20
20
19
35
280
15
1980
20
20
20
20
30
350
30
Exports
1974
42
74
83
37
80
4
37
36
255
15
1980
50
55
100
45
90
5
40
30
400
20
Total
Demand And
Shipments
1974
1290
1444
1464
512
675
154
352
563
3217
148
1980
2585
2735
1910
830
846
240
310
628
3150
90
Total
9617 12,979
461 490 663 835
9819 13,324
Source: 1974 Data, Textile Organon Dec. 1975
1980 Projections, Arthur D. Little, Inc. estimates.
-------
5-
4-
o
a.
'Z
o
3-
2-
1-
KEY
INDUSTRIAL
HOME
FURNISHINGS
APPAREL
1974 1980
POLYESTER
1974 1980
NYLON
1974 1980
OLEFIN/ACRYLIC
1974 1980
MAN-MADE
CELLULOSICS
1974 1980
COTTON
1974 1980
WOOL
Source: Arthur D. Little, Inc. compiled data.
Figure III-2. Fiber Consumption by Type and Product Category, 1974 and 1980
-------
TABLE III-4
TEXTILE MILL PRODUCTS TRENDS, 1967-74
(In millions of dollars, except as noted)
Value of shipments
Thousands employed
Value added
Value of Imports
Value of Exports
Wholesale price index
1967
19,815
958.5
8,153
803
377
100.0
1971
24,030
957.0
9,995
1,248
465
103.7
1972
27,430
991.0
11,366
1,379
638
111.6
1973
31,073
980.2
13,017
1,421
1,001
128.6
19742
33,335
940.0
14,000
1,630
1,275
147.8
Value of all products and services sold by the textile products industry (SIC 22).
Estimated by Office of Textiles, Bureau of Labor Statistics.
Source: Bureau of the Census; Office of Textiles, Bureau of Labor Statistics.
TABLE III-5
BROADWOVEN FABRICS, 1974 PROFILE
SIC Codes 221, 222, 223
Value of industry shipments
($ million) 8,210
Number of establishments
(1972) 917
Total employment (000) 298
Exports as a percent of product
shipments 9.0
Imports as a percent of apparent
consumption 7.9
Compound average annual rate of
growth 1967-74 (percent)
Value of shipments
(current $) 2.9
Value of exports
(current $) 19.6
Value of imports
(current $) 10.3
Employment -2.4
Major producing areas Atlantic Coast
and South
Source: U.S. Industrial Outlook 1976. U.S. Department of Commerce.
22
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TABLE III-6
KNIT FABRICS MILLS, 1974 PROFILE
SIC Codes 2257, 2258
Value of industry shipments
($ million) 4,500
Number of establishments
(1972) 896
Total employment (000) 89
Exports as a percent of product
shipments 1.0
Imports as a percent of apparent
consumption 1.0
Compound average annual rate of
growth
1967-74 (percent):
Value of shipments
(current $) 11.1
Value of imports
(current $) 19.8
Employment 13.8
Major producing areas Middle and
South Atlantic
Source: U.S. Industrial Outlook 1976. U.S. Department of Commerce.
Historically, profit margins in the textile industry have been sub-
stantially lower than the all-industry average. In good years, after-tax
profits typically represent 3% or less of sales for all major textile pro-
ducers. There is no reason to believe that this profit level will improve
substantially in the future. In fact, higher labor costs, escalating energy
costs, and capital investment demands required to comply with recent environ-
mental and health legislation may cause further erosion.
Capital expenditures for new plants and equipment are estimated to be
$660 million in 1975, down from $840 million in 1974, and $770 million in
1973, representing the highest expenditure since $820 million in 1966. About
5% of this investment was spent in 1973 and 1974 to meet air and water
quality standards set by the Environmental Protection Agency and the Occupa-
tional Health and Safety Standards set by the Department of Labor. These
investment costs are expected to continue over the next five to ten years,
and will compete with the capital funds that can be assigned to new techno-
logical activity affecting product type and quality.
Total hourly wages for production workers in the labor-intensive textile
industry averaged $3.37 in mid-1975, up 6% from $3.15 in 1974. Employment
dropped sharply, from 1.03 million in 1973 to 910,000 in mid-1975 and only
started to recover in late 1975. Product sales amount to about $30,000 per
hourly employee, showing that the industry is highly labor intensive. Compe-
tition for hourly labor in the Southeast has increased sharply in recent
years, so wage rates may increase at a faster rate to approach the average
for all manufacturing in the region.
23
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4. Energy Costs
Traditionally, energy costs have not been a major factor in the produc-
tion of textile fabrics because much of the production has benefited from
low-cost natural gas and electricity. With deregulation, or the need to
obtain new gas supplies, the impact could be considerable. Natural gas is
an essential fuel for certain textile operations (e.g., heat setting) because
the combustion products come in contact with the fabric. Fuel oil, at a sub-
stantially higher cost, is being increasingly substituted for natural gas in
steam raising operations.
Actual energy costs vary widely with the type of fabric and the product
mix and, according to industry estimates, range from 2-8£/lb of fabric.
Knit goods such as hosiery tend to be at the low end, while heavy woven
fabrics tend to be at the high end. However, geographic location and product
mix can also cause large variations in energy cost.
24
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IV. COMPARISON OF CURRENT AND ALTERNATIVE PROCESSES
A. BASIS FOR PROCESS SELECTION
1. Total Energy Use
The 1971 Census of Manufactures provides data on energy use in the form
of purchased fuel and purchased electricity using the standard SIC classifi-
cations. This classification divides the textile industry into nine groups.
(See Table IV-1.) For the purposes of this study, the figures in the table
have been converted from kilowatt hour equivalents to Btu equivalents, using
the conversion factors indicated. (It was mentioned earlier that this SIC
classification suffers from a number of limitations in relating energy use
and pollution potential to the various unit operations which are carried out
by the textile industry; however it still represents the only data base.)
Four SIC categories comprise 66% of the total energy used in the textile
industry, as shown in Table IV-1. These categories are: 221, Weaving Mills
Cotton; 222, Weaving Mills Synthetic; 225, Knitting Mills; and 226, Textile
Finishing. We can therefore establish the potential for energy conservation
under these four categories by examining in detail two different types of
textile mills; i.e., an integrated knitting mill, (which knits greige yarn and
subsequently dyes and finishes* the fabric), and an integrated weaving mill
(which weaves greige fabric and then dyes and finishes the fabric). In addi-
tion, we would anticipate that some of the data on energy-conservingprocess
options examined in this manner can be extrapolated to estimate potential
energy savings in other sections of the textile industry, such as yarns and
carpet. Although similar unit operations are used, there are considerable
differences in the processes for weaving and finishing wool. However, wool
processing presently accounts for less than 3% of total textile energy use
and a separate treatment is not justified in this report. To focus the
effort on appropriate unit operations we used in-house data to obtain a first
estimate of energy use, by area of processing, for a knit fabric mill and a
woven fabric mill.
2. Integrated Knit Fabric Mill
Energy consumption for knit fabric manufacture can be broken down as
shown in Table IV-2. We estimate that about 27,000 Btu per pound of cloth
are expended, from yarn manufacture to finished fabric. Slightly less than
*Note that "finishing" is commonly used to indicate combined operations,
which include fabric preparation and dyeing in addition to specialized
"finishing" operations which consist of end treatments to provide durable
press characteristics, water repellency, etc.
25
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TABLE IV-1
FUEL AND ELECTRIC ENERGY USE IN THE TEXTILE INDUSTRY, 1971
Code
221
222
223
224
225
226
227
228
229
Purchased Fuel Purchased Electricity
Industry Croup Ittn Kqiilv. x 10 Btu K««lv. x 10
Weaving Mills Cotton
Wcavins Mills Synthetic
Weaving & Finishing Mills, Wool
Narrow Fabric Mills
Knitting Mills
Textile Finishing (except Wool)
Floor Covering Mills
Yarn & Thread Mills
Miscellaneous Textile Goods
30.02
31.39
10.58
3.75
48.79
80.86
29.68
20.13
23.54
57.01
58.52
5.35
3.54
32.77
16.69
9.68
57.89
20.23
Total
Btu Enulv. x 10
87.03
89.91
15.93
7.29
81.56
97.55
39.36
78.02
43.77
Z
16.12*
16.65*
2.95
1.35
15.11*
18.07*
7.29
14.45
8.11
22 Textile Mill Products 278.42 261.45 539.87 100
(1) Converted from Census table on the basis of 1 kkli - 3,412 Blu
(2) " " " " " " " " 1 kWh 10,500 Blu (energy required at the generating plant).
* Total energy use in these categories represents more than 66Z of textile Industry energy consumption.
Source! 1972 Census of Hnniif.iRturi-g
TABLE IV-2
ENERGY USE IN AN INTEGRATED KNIT FABRIC MILL
OPERATION
GKEICE FABRIC MANUFACTURE
Tarn Manufacture
Preparation
Weaving
Air Conditioning
Lighting
Miscellaneous
Subtotal
FABRIC FINISHING
Preparation
Dyeing
Finishing
Lighting
Miscellaneous
Subtotal
Total
103 Btu/lb
3.9"!
3.40
1.53
6.29
1.19
0.68
17.00
5.61
6.12
5.27
0.60
0.40
18.00
35.00
X
11.2
9.7
4.4
18.0
3.4
1.9
48.6
16.0
17.5
15.1
1.7
1.1
51.4
100.0
Note: In this Table, electrical energy la calculated as energy used in
che process.
Source: Arthur D. Little, Inc. Estimates
26
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half of the energy is consumed in greige fabric manufacture and the rest is
in fabric finishing. However, 27% of the total energy is used for lighting
and air conditioning which are essential, but are not directly related to
process operations. Thus, the potential for energy conservation lies with
fabric finishing operations, and is about equally divided between preparation,
dyeing, and finishing. About 80-90% of the energy is consumed as thermal
energy in the form of natural gas or steam (produced by oil or gas). The rest
is electricity consumed as mechanical energy. In practice, most of the steam
is used to heat the process and wash water, and the gas is used to dry and
heatset the finished fabric.
3. Integrated Woven Fabric Mill
Similar estimates were made for an integrated woven fabric mill, and the
result shown in Table IV-3. The 35,000 Btu expended per pound of woven fabric
is again about equally divided between greige fabric manufacturing and fabric
finishing.
In greige fabric manufacturing, of the 3,400 Btu/lb used for preparation,
about 2,900 Btu/lb are needed to provide the steam used in sizing (slashing).
The largest fraction is again electricity required for air conditioning. In
fabric finishing, energy use is again about equally divided between prepara-
tion, dyeing, and heating, with a very high proportion in the form of thermal
energy. Steam is used for heating water, fixing vat or reactive dyes, and
for heating "cans" that dry the fabric as it passes over them. Gas is used
for drying, heatsetting, in dyeing operations (thermal-setting processes),
and in curing of finishing chemicals.
4. Selection of Advanced Unit Operations
We began our search for potential energy-saving unit operations by eval-
uating the recent textile literature, examining EPA demonstration projects,
and talking with outside consultants and industry personnel. It soon became
obvious that there are a large number of potential energy-saving process
options for individual unit operations, particularly in fabric preparation
and in the dyeing and finishing operations. It became necessary to limit
the search, so the selection was limited to those process developments which
appeared to have a broad applicability and were sufficiently developed to be
available now (or at least read,y for pilot-scale operation).
Because the major fraction of energy use in the textile industry is
spent in heating and evaporating water, water conservation or elimination of
water use represents a crucial part of the analysis. Methods or equipment
that provide improved contacting, mixing, or elimination of water from the
farbic were evaluated as part of the overall process operations. Those
process options that survived to the final selection process are discussed
in the following sections under advanced processing for water-based systems,
and under solvent processing for all-solvent systems. Hybrid water/solvent
systems were eliminated, because we believe they would incur both energy and
pollution penalties.
27
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TABLE IV-3
ENERGY USE IN AN INTEGRATED WOVEN FABRIC MILL
OPERATION
GREIGE FABRIC MANUFACTURE
Yarn Manufacture 2.74 10.0
Knitting 1.00 3.6
Air Conditioning 6.29 23.0
Lighting 1.19 4.3
Miscellaneous 0.68 2.5
Subtotal 11.90 43.5
FABRIC FINISHING
Preparation 4.77 17.4
Dyeing 5.20 19.0
Finishing 4.48 16.4
Lighting 0.60 2.2
Miscellaneous 0.40 1.5
Subtotal 15.45 56.5
Total 27.35 100.0
Note: In this Table, electrical energy is calculated as energy used in the
process.
Source: Arthur D. Little, Inc. Estimates.
5. Advanced Processing
a. Aqueous Sizing
Most woven goods require the use of warp size during manufacture. The
sizing (traditionally starch) coats and protects the warp yarns and binds the
individual fibers together. This action is necessary to'preserve the warps
from excessive abrasion damage during weaving. The sizing is generally
removed as the first operation in the fabric finishing sequence. Warp size
constitutes, on the average, about 5% of the weight of the fabric, and it all
ends up in the effluent waters after desizing. Accordingly, it is a substan-
tial contributor to the total BOD and COD in textile mill effluents. Sizing
waste generally accounts foj about 50% of the total BOD and COD load from
textile woven-fabric operations.
Polyvinyl alcohol (PVA) represents the material of choice for warp siz-
ing of synthetics, such as polyester and polyester/cotton blends. Its use
in the textile industry roughly parallels the growth of synthetic fiber use
and now accounts for about 60% of all size used in the textile industry. PVA
adheres to polyester better than starch size and, in addition, leads to
faster fabric processing with less yarn breaking and shedding at the slasher
and at the loom. However, these sizing advantages imparted by the properties
of PVA tend to work against its removal in desizing.
28
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PVA is unaffected by enzymes systems used to degrade and solubilize
starch and is generally removed from the fabric by desizing with detergent
in hot water. For effective size removal, PVA-sized fabrics must be subjected
to water rinses at temperatures of 190°-200°F, because any PVA that remains
on the cloth after desizing affects subsequent operations such as alkaline
scouring and finishing. This leads to high energy losses in the hot waste-
water effluent from the washing operations. It has been demonstrated that
PVA can be recovered by ultrafiltration through temperature-resistant and
chemically coated, inert carbon tubes. The purified wash water is also
recycled to the process (Gaston County Dyeing Machine Co., 1974a, and Textile
Industries, 1974). This process has now been commercialized* and over 20
million yards of polyester/cotton fabric have been processed with reclaimed
size. There have been no serious operating problems with the filtration
system, after two years of operation.
Further development of the techniques of PVA reclamation, and the exten-
sion of its use to other fibers and weaves, will probably occur on the basis
of good return on investment. The modular construction of the recovery
units would appear to make the technique applicable even to small mills.
b. Water Conservation
Typically, washing or rinsing after wet processing steps such as scour-
ing and dyeing uses one to three times as much hot water as the process step
itself and in some operations (e.g., continuous dyeing) much higher ratios
are found. Hence, improved washing methods offer significant energy savings.
Techniques being developed include more effective continuous countercurrent
rinsing. One report (Textile Industries, December 1975b) proposes rinsing
at slightly elevated pressures in continuous equipment to provide more effi-
cient removal of chemicals, such as the sodium hydroxide used in mercerizing
operations. Experimental units using vibrating-reed jet washers and cam-
driven beater rollers** are on field trial in the textile industry. Development
work is also being conducted with the use of mechanical devices (Gaston
County Dyeing Machine Co., brochure a) to increase water turbulence and with
the use of sonics (Textile Industries, December 1975a) to increase the rate
of dirt and excess dye removal.
Reuse of hot wash waters from dyeing operations after treatment by
reverse osmosis (hyperfiltration)1 is the objective of an EPA demonstration
project (LaFrance Industries; and Brandon, Nasher, and Porter, 1975).
Successful pilot-scale tests at one plant have shown that 65-90% water recov-
ery can be obtained and the concentrate containing all the chemicals can, in
some instances, be reused in the dyeing step.
*A PVA System designed and constructed by Gaston County Dyeing Machine Co. is
in operation at the J.P. Stevens Mill in Clemson, S.C.
**Riggs & Lombard, High Efficiency Washer observed at Charlton Woolen,
Charlton, Mass.
29
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c. Processing at Low Liquor/Fabric Ratios
Current practice in the textile industry uses a variety of dyeing
machines, some of which have been in service for a long time. These include
open dyebecks, and pressurized dye machines. Considerable energy savings
can be achieved by enclosing the open becks to prevent evaporation and insul-
ating them to reduce heat loss. The use of pressurized machines results in
considerably less use of dye and water. We estimate that raising the aver-
age level of operations to the level of the best presently existing in the
industry might save 15-20% of the current energy use in dyeing operations,
or about 2-3% of the total'energy used in a typical mill.
The reduction of water use in a typical dyeing unit operation is compli-
cated by the fact that as the liquor-to-cloth* ratio decreases, there is
more difficulty in- applying dye uniformly to the fabric and, therefore, in
obtaining uniform color in the final product. This problem varies with the
particular dye/fabric combination being used. However, processes and equip-
ment have been developed for dyeing at very low liquor-to-cloth ratios which
still allow uniform dyeing to be consistently achieved (Textile Industries,
May 1975). The use of 5:1 liquor/fabric ratios have been demonstrated for
batch dyeing of knit fabric. This is a considerable reduction from the com-
monly used 15:1 to 10:1 ratios, with consequent savings in energy and water
use. Its applicability to a wide range of textile fabrics has been demon-
strated in pilot-plant work by the equipment manufacturers, (Gaston County
Dyeing Machine Co., brochure b) but adoption by the industry will require
capital investment in new equipment, and additional experimentation.
Dyeing of woven goods, particularly pad dyeing of polyester with disperse
dyes (thermosol process) and of cotton with reactive dyes, is commonly prac-
ticed. However, not all shades and fabrics can be processed in this manner.
Low liquor-to-fabric ratios have also been successfully employed in
other process operations such as scouring (10:1 from 20:1) and washing, (8:1
from 25:1).
The use of 8:1 in place of 25:1 water-to-fabric ratios for open-width
washing of woven goods has been demonstrated in practice (Carp, personal
communication), but its applicability to all fabric types needs further
demonstration.
d. Vacuum Impregnation and Extraction
Vacuum impregnation (Textile World; 1972) has been found useful in dye-
ing certain fabrics, because the removal of air from the fabric results in
more rapid and even dye penetration, with a consequent reduction in dyeing
time and lower liquor-to-cloth ratio. With this equipment, the fabric closely
contacts a perforated cylinder and air is extracted by the vacuum. Dye
solutions and fabric come into contact prior to the fabric's return to normal
atmospheric pressure, thus promoting penetration of dye into the fabric. This
*A solution containing dye and other chemicals.
30
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technique is particularly useful with heavy fabrics, such as corduroy, which
are difficult to dye uniformly by conventional means. Vacuum impregnation
is also potentially applicable to various finishing processes, such as durable-
press and flame-retardant finishing.
Evaporation of water represents the largest energy-consuming portion of
textile processing. Typically, fabric after wet operations followed by
squeezing between mechanical rollers still contains 50-100% of its weight
as water, depending on the particular fabric being treated. Vacuum extrac-
tion (International Textile Machinery, 1975) by the use of porous rollers
will reduce the water content more effectively and thus reduce the energy
required for drying.
One manufacturer (Zeiffer) markets an air/vacuum extractor device that
permits lowering the water pickup on polyester doubleknit fabric below 20%.
According to published data,-the mechanical water-removal methods show more
advantage with synthetic fibers (or blends with at least 65% synthetic fiber).
Natural fibers such as cotton are hydrophilic, and conventional squeeze rolls
appear to be nearly as effective as vacuum extraction in removing water from
this type of fabric.
e. Finishing
There are a number of improved finishing techniques under development
which include application of low-temperature curing resins, and radiation
curing of resins (Textile Industries, November 1975), which offer the promise
of lower energy consumption. However, these techniques have not yet been
commercially accepted. One technique which is now being used in commercial
practice (Gaston County Dyeing Machine Co., personal communication) is the
application of finish solutions that use considerably less water to dilute
the finish solution, emulsion, or suspension. The conventional method is to
dip dry fabric in a finish pad and then express the excess finish solution
by squeeze rolls. This gives a total water pickup of 60 wt % of the fabric.
The advanced technique uses a vacuum extractor (or a transfer roll) that
limits solution pickup to about 16 wt % of the fabric, thus reducing the
water content that must be evaporated in the heat set tenter. An additional
benefit claimed is that less finish is lost from the fabric during heat
setting.
6. Solvent Processing*
Solvent processing offers the prospect of substantial energy savings
over conventional aqueous processing, principally because about 8.6 times
more energy is required per pound to heat and vaporize water (1162 Btu/lb)
than to heat and vaporize typical organic solvents such as perchloroethylene
(135 Btu/lb). Further, because non-aqueous solvents have higher vapor pres-
sures, drying rates are appreciably faster. Solvent processing is poten-
tially applicable to most of the major textile operations now carried out by
wet processing, such as sizing and desizing, scouring, bleaching, dyeing,
and various finishing processes. However, solvent processing is not without
*(Textile Industries, 1970; Reinhart & Reid, 1973; and Willard, 1973)
31
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major potential economic and pollution disadvantages. Direct solvent losses
from the process can be in the range of 5-8%, and most of the solvent must
be recovered to make the economics of the process acceptable and to meet
air quality requirements. However, there are existing installations in the
textile industry with carbon adsorption systems for solvent recovery which
claim acceptable economics and compliance with air pollution regulations.
In the course of this work, it has become clear that chlorinated sol-
vents such as perchloroethylene and trichloreothylene are the most suitable
materials now available and, to date, there has been no appreciable commer-
cial use of solvent finishing for woven goods. However, solvent processing
has established a firm, if specialized, position for the finishing of syn-
thetic knit fabrics.
Solvent processing has also found commercial use only where superior
fabric properties have been achieved. For example, solvent applications of
stain-repellent finish to upholstery and drapery materials are widely prac-
ticed. In this case, aqueous treatment is not always possible, because the
fabric is sensitive to water. Similarly, solvent scouring and finishing of
synthetic knit fabrics is widely practiced, because improved quality is
obtained by avoiding contact with water. Some finishes, furthermore, are not
available in water-soluble or water-dispersible form and can be used only in
solvents. However, before introduction of all-solvent processing, consider-
able investment in new equipment would be required, together with development
of an expanded range of solvent-compatible reagents, dyes, and finishing
chemicals.
a. Sizing and Desizing
Desizing of starch-base sizes can be accomplished by treating the fabric
with an enzyme suspension in trichloroethylehe solvent followed by steaming
to remove trichloroethylene solvent. ("Textile Industry and the Environment,"
1973) The degraded starch is not reusable and goes to the waste treatment
plant. PVA, CMC, and acrylic sizes can also be removed by dissolution in
solvents. In this case, reuse of the size is possible and would reduce process
and waste treatment costs.
b. Scouring, Bleaching, Mercerizing
The widest application of solvent processing to date has been in the use
of solvent scouring (Willard, 1973) to prepare knit fabrics for dyeing. Batch-
type dry cleaning equipment is used commonly, both in Europe and the United
States. Continuous scouring and finishing equipment for circular knits has
recently been made available from a number of suppliers. These process units
are engineered to minimize air pollution problems. Under the processing con-
ditions, chlorinated solvents are not retained inside the fiber.
c. Dyeing
Continuous-dyeing and exhaust-dyeing systems have been examined in great
depth, but major problems still exist in both areas which must be solved
before extensive application of solvent dyeing can be achieved» Chlorinated
solvents may be retained by polyester fiber after dyeing to the extent of
32
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5-7% by weight of the fabric or yarn (Willard, 1973). This solvent must
be removed and recovered in subsequent operations. The widest application
of solvent dyeing to date has been in batch dyeing of synthetics, such as
nylon knit sportswear.
Experimental work has shown that superheated solvent vapor can be used
for dispersed dyes on polyester (Textile Industries, 1973). The same
principle is also applicable for dispersed and acid dyes on polyamide fibers
and reactive dyes on acrylonitrile fibers.
Solvent dyeing of cotton/polyester blends may be possible as a result
of recent developments, where the cotton component was dyed using dimethyl
formamide (DMF) and perchloroethylene. (Byland, Capponi, Gerber, and Somm,
1971)
d. Finishing
Durable-press finishes for cottons and cotton blends can be applied from
chlorinated solvents. (JAATCC, 1973) Chemicals used must either be emulsi-
fied in the solvent or must be chemically modified to make them soluble,
which requires that the treated fabric be exposed to steam to effect fiber
swelling and penetration.
At present, most finishes are designed to be applied from aqueous solu-
tion as emulsions or dispersions. This situation is partly a result of
integration with existing water-based processing, so new approaches could be
tried for a mill based completely on solvent processing.
B. COMPARISON OF CURRENT AND ALTERNATIVE PROCESSES
1. Integrated Knit Fabric Mill
a. Process Description
Our model base line plant in this category was based on good operation
with present practices and conventional equipment. It is assumed that reason-
able housekeeping measures have already been enforced to conserve energy by
reducing water use.
(1) Base Case
The mill was chosen to have a production of 22,uOO Ib/day of a 100%
polyester doubleknit using purchased texturized yarn.* It includes the
sequence of unit operations shown in Figure IV-1. Yarn is first knitted
into a fabric in the greige mill. This greige fabric then goes through a
scouring operation to remove knitting oil, followed by dyeing, washing, and
spin drying to remove as much water as possible before hot-air drying. A
finish (softener/lubricant) is then applied to the fabric, which is dried
and heat set. Process water is required for the scouring, dyeing, and
washing operations, and this is combined into one wastewater effluent.
*An integrated mill can also include yarn spinning operations.
33
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PRODUCTION: 22,000 LB/DAY - 100% POLYESTER DOUBLEKNIT
YARN
WATER
DAI LY EFFLUENT STREAMS
114.000 GAL NON-CONTACT COOLING WATER AT 140°F
(WJ 136,000 GAL PROCESS WATER AT 100°F
/A\ 586 MCF FLUE GAS AT 120°F
5780 MCF FLUE GAS AT 380°F
BOD = 550 LB
COD = 1760 LB
TSS 180 LB
SOME PARTICLES (LINT)
POSSIBLE
22 LB HYDROCARBON (FROM
FINISHING CHEMICALS)
SOME PARTICLES (LINT)
POSSIBLE
FINISHED FABRIC
Figure IV-1. Flow Diagram: Integrated Knit Fabric Mill - Base Case
34
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Live steam is used for the heat input to scouring, dyeing, and washing
operations; natural gas is used for the hot-air drying and heat-set
operations and results in flue gas effluents to the air. Varying amounts of
electricity are used to provide mechanical energy to transfer fabric from the
beginning to the end of the process line and for knitting the yarn into
fabric. The use of electricity for air conditioning in the knitting section
of the mill is substantial and air conditioning is essential to satisfactory
operation of the knitting machines. However, this does not bear directly on
the process energy use and is not changed by going to advanced processing.
Therefore, we have eliminated it from direct consideration.*
Process water effluent contains a variety of organic and inorganic
materials from the chemicals used in processing. These include dyes, dye
carriers, detergents, sequestering agents and dissolved salts. The effluent
undergoes biological treatment before discharge for pollution control
purposes, so the effluent is defined in terms of its biochemical oxygen demand
(6005), chemical oxygen demand (COD), and total suspended solids (TSS). The
combined untreated waste from knit-fabric finishing mills will generally con-
tain 100 to 500 mg/1 BOD 5, 40 to 485 mg/1 TSS, and 450 and 1500 mg/1 COD.
Flue-gas effluents from the hot-air dryer and the heat-set tenter con-
tain only minor amounts of pollutants. Some lint particles are possible
from both units and a small amount of organics from the finishing chemi-
cals will be present in the flue gas effluent from the heat-set tenter.
C2) Advanced Case
The sequence of process operations for the mill using advanced process-
ing is similar (see Figure IV-2)-, except that mechanical water removal has
been introduced in the form of an air/vacuum extractor as an alternative to
the hot-air dryer. A second air/vacuum extractor has been added to the
finishing operation to remove excess water before passing the fabric to the
heat-set tenter, which therefore reduces the energy requirements (natural
gas) for the heat-set operation. We have assumed that the vacuum extractor
will remove water down to about 25% of the fabric weight without effecting
the fabric quality.
Substituting modern, efficient equipment, process water use in the scour-
ing, dyeing, and washing operations has been reduced. For scouring, the
20:1 water-to-fabric ratio used for the base case has been reduced to 10:1,
and the process water for this operation is recycled cooling water from the
dyeing operation. Similarly, the ratio of dye liquor to fabric has been
reduced from 10:1 to 5:1 (although the dyes and chemicals used will be approx-
imately the same). The water-to-fabric ratio in the final wash has been
reduced from 35:1 to 7:1.
*The use of waste heat from air conditioning and/or space heating is out-
side the scope of this study.
35
-------
PRODUCTION: 22,000 LB/DAY - 100% POLYESTER DOUBLEKNIT
WATER STEAM YARN
EFFLUENT STREAMS
FINISHED FABRIC
26,000 GAL NON-CONTACT COOLING WATER AT 140°F RECYCLED
56,000 GAL NON-CONTACT COOLING WATER AT 100°F
45,000 PROCESS WATER AT 100°F
1860 MCF FLUE GAS AT 130°F
BOD = 550 LB
COD = 1760LB
TSS 180 LB
22 LB HYDROCARBON (FROM
FINISHING CHEMICALS)
SOME PARTICLES (LINT)
POSSIBLE
Figure IV-2. Flow Diagram: Integrated Knit Fabric Mill - Advanced Case
36
-------
Steam is no longer required in the washing operation, and the natural
gas requirements have been eliminated for the drying step and reduced for the
tenterframe. (See energy section.)
These advanced operations do not change the pollution load in the efflu-
ent water appreciably, but they do reduce the total volume of water for
treatment by over 65%, thereby effecting a considerable savings in biological
treatment costs.
(3)' Solvent Case
Solvent systems (Textile Industries, 1970; and Reinhart & Reid, 1973)
are being used for scouring synthetic knit fabric prior to dyeing and finish-
ing, and we can presume that solvent scouring is an accepted method of treat-
ment for polyester doubleknits.
Solvent dyeing, on the other hand, is not a developed, practicable method
even for synthetic fibers. The published literature describes many methods
for solvent dyeing, but we were unable to obtain verification that any sol-
vent dyeing is practiced commercially. Thus, for our evaluation of solvent
processing, we have assumed (by analogy with previous processing) that a
solvent dyeing machine and a solvent finishing machine will be roughly equiv-
alent to the scouring machines now in use.
The solvent machines are purchased as packaged units, complete with
solvent distillation equipment, vapor recovery, and tanks and pumps for segre-
gation of solvents in a system. Three machines have been linked in series,
as shown in Figure IV-3, to provide the process operations of scouring, dyeing,
and finishing.* Fabric is first scoured to remove knitting oil then trans-
ferred to the second machine where it is dyed. Polyester is wetted by perchlor-
oethylene, so we surmise that smaller amounts of auxiliary chemicals will
be required to obtain adequate dye penetration. Then the fabric is transferred
to a third machine to remove excess dye and, finally, steam stripped to remove
residual perchloroethylene and give an essentially dry fabric for the final
heat-set operation.
Periodically, contaminated solvent from each operation is transferred to
the common solvent still and clean solvent is recovered by distillation with
steam. The condensate from the finishing operation and the still represents
the only waste water effluent that may contain traces of solvent and- other
chemicals. Knitting oils removed in scouring and chemicals from dyeing and
finishing remain as residues in the solvent still and are removed as a solid
waste for disposal (probably by incineration).
The process units are surrounded by an enclosure maintained at a nega-
tive pressure by exhausting air continuously. Exhausted air containing sol-
vent vapors is passed through an activated carbon vapor recovery system
before discharge to the atmosphere. Periodically, the activated carbon is
stripped with steam and the solvent vapors are returned to the solvent
recovery still.
*Equipment specifically designed for all-solvent processing might consist of
a single machine equipped to carry out scouring, dyeing, and finishing in
sequence.
37
-------
PRODUCTION: 22,000 LB/DAY - 100% POLYESTER DOUBLEKNIT
STEAM
NATURAL
GAS '
SOLVENT
MAKEUP
YARN
II
II
KNIT
IP T = = != = =
II
SCOUR
DYE
WASH&
FINISH
^=rfTOl
SOLVENT
ST|LL
I
VAPOR
RECOVERY
HEAT
SET
, COOLING
WATER
STEAM
FINISHED FABRIC
EFFLUENT STREAMS
86,400 GAL NON-CONTACT COOLING WATER AT 104°F
3,000 GAL PROCESS WATER (STEAM CONDENSATE) AT 80°F
4 LB PERCHLORETHYLENE
5,600 MCF AIR AT 85°F, CONTAINING 216 LB (80 PPM)
PERCHLORETHYLENE
1,860 MCF FLUE GAS AT 130°F, CONTAINING 22 LB ORGANICS (FROM
FINISHING CHEMICALS, SOME PARTICULATE (LINT) POSSIBLE
1,200 LB/DAY SOLID WASTE (KNITTING OIL, DYES AND FINISHING
CHEMICALS)
Figure IV-3. Flow Diagram: Integrated Knit Fabric Mill - Solvent Case
38
-------
According to manufacturers' data, solvent losses are about 3% of the
fabric weight in present solvent-scouring systems. We believe that solvent
losses will need to be reduced to less than 1% to meet air quality regulations.
(American Periodic, Inc.)
b. Energy Requirements
Electrical energy is consumed in all the process operations in the form
of mechanical energy to move the fabric through the process operations and to
knit the yarn into fabric. Steam is used to heat the process operations that
use water, and natural gas is used to dry the fabric. The combustion gases
are applied directly to the fabric, so a clean fuel is required. Oil and coal
are not substitutable fuels in this section of the process.
A summary of the energy use (base and advanced case) is provided in
Table IV-4. Electrical energy consumption is about 4,000 kWh/day in the base
case and this is increased 37% in the advanced case due to the substitution
of the air/vacuum extractors which require significantly more mechanical
energy. Steam use is 90 million Btu/day in the base case, but this is reduced
by 50% with advanced processing. Natural gas is reduced by about 90% in the
advanced case by optimization of the air flow, addition of an integrated
heat-recovery unit on the heat-set tenterframe, and by elimination of natural
gas from the drying step. Energy consumed "at the source" is reduced by 50%
to 155 million Btu/day with advanced processing. To obtain this conversion
we assume that 1 kWh is equivalent to 10,500 Btu; i.e., the heat requirement
at the generating plant. Steam use has an overall efficiency of 50% and
natural gas is assumed to have an efficiency of 100%, because it is consumed
directly in the process unit. Electrical energy can be provided by coal-
based generating plants, so a change from natural gas to electricity is a form
of conservation.
Energy requirements for solvent processing are estimated to be 2740 kWh
for electricity, 26.4 million Btu steam (much of the steam is required for
solvent recovery), and 8,4 million Btu for natural gas. (These data were
calculated by extrapolation of manufacturers' data for solvent scouring
systems. Relnhart & Reid, 1973,) Calculated as energy consumed at the source
with the same conversion factors as before, the total energy consumed is 54.8
million Btu, which is an 82% reduction from the base case.
c. Economics
(1) Common Cost Factors
There are a number of common cost factors that apply to knit and woven
fabric operations.
Energy costs for natural gas ($1.85/MCF) have been based on the estimated
prices paid in March 1975 by electric utilities. We have found that such
prices are consistent with prices reported by SIC sector in the 1972 Census
wnich. were escalated by fuel cost indexes to 1975 prices. Cost of steam is
C$4,07/1000 Ib) based on use of a "package" unit fueled by oil. It should
be recognized that most of the gas and electric utility industry is regulated,
so the price prevalent in the first half of 1975 would not necessarily be
39
-------
TABLE IV-4
SUMMARY OF ENERGY CONSUMPTION: KNIT FABRIC MILL
(Production, 22,000 Ib/day)
BASE CASE
Elec-
trical Steam
Natural
Gas
Process Operation
Scour
Dye
Wash
Dry
Finish
kWh
80
803
117
197
2818
106 Btu
26.8
57.7
5.6
105 Btu
33.5
53.1
ADVANCED CASE
Elec- Natural
trical Steam Gas
kWh 10" Btu 10° Btu
80 6.5
803 38.5
117
1800
2709 8.4
4015
90.1
5509
45.0
8.4
ENERGY CONSUMED AT THE SOURCE
BASE CASE
Elec-
trical S:
n6
Natural
team Gas
10° Btu equiv.
ADVANCED CASE
Elec- Natural
trical Steam Gas
1Q6 Btu equiv.
42.1
180.2
Total (rounded)
1
308.9
86.6
I
56.5
I
90.0
8.4
154.9
(50% reduction)
Assumptions: Electrical Energy, IkWh = 2,646Kcal (10,500Btu). All electrical energy is consumed as mechanical
Steam: 70% boiler efficiency; 20% distribution losses. energy.
Natural Gas: direct combustion in the process 100% efficiency
Electrical energy consumed for knitting, air conditioning, and lighting, is excluded.
indicative of the costs that a new plant built upon a greenfield site would
incur. Estimates indicate that the cost of natural gas for such new facili-
ties may be similar to the price of oil. Similarly, the price of electric
power might be higher than electric power costs in early 1975.
The cost of water suitable for cooling purposes has been based on $0.03
per thousand gallons. The cost of treated process water is based on $0.20
per thousand gallons.
We have used the wage rate published by the Bureau of Labor Statistics
for March 1975 by industry sector to calculate labor costs. For the textile
industry, this cost is $3.30/hr. Cost of raw materials are based upon typical
costs in the first half of 1975. Texturized polyester for knit fabrics is
priced at $1.10/lb and polyester is priced at $0.51/lb and cotton at $0.55/lb
for woven fabrics.
The costs of maintenance, labor,-and materials have been taken as 2.5% of
initial investment cost. Labor overhead has been taken at 25% of labor wages.
This would account for fringe benefits, such as vacations, holidays, and sick
pay, in addition to overtime pay.
Under the category of fixed costs we have shown plant overhead at 100%
of production labor; it is textile industry practice to include production
supervisors and most other personnel in this area. Local taxes and insurance
are taken as 1.5% of the initial capital investment.
40
-------
To distribute the cost of the capital assets (less salvage value, if any),
over the estimated life of the facility, annual depreciation is calculated on
a straight-line basis over 12 years for the textile industry. In addition to
being used often in feasibility studies, this depreciation schedule is con-
sistent with previously published IRS guidelines (Davidson 1970; Perry, et
al., 1969).
We show an annual allowance for "return on investment" (pre-tax) amount-
ing to 20% of initial capital investment. We have segregated the pollution
costs, except where pollution control equipment is considered to be a part of
the plant, such as in solvent processing of knit fabric, where we included
those in the plant operating costs. In determining pollution control costs,
we followed the same methodology for the variable and fixed costs. We rec-
ognize that this interpretation may be subject to question, because of the
different methods of financing pollution control equipment.
(2) Integrated Knit Mill
A summary of production economics for an integrated knit mill is shown in
Table IV-5 for the base case and in Table IV-6 for the advanced case. It is
assumed that the annual production is based on 250 stream days (5.5 million
Ib/year), i.e., a 5-day week with 3-shift operation. Capital investment is
based on mid-1975 estimates and does not contain any inflation factor. The
fixed investment for a new grassroots plant, exclusive of pollution control
costs, is estimated at $14.1 million for the base case and $14.6 million for
advanced processing. The raw materials used are polyester fiber plus a
variety of chemicals for fabric, preparation, dyeing and finishing. Energy
use consists of natural gas, electric power, and steam. In the latter case,
we assumed that steam is provided from a central boiler facility which also
provides steam for space heating and other purposes. The fuel used for steam
raising has previously been natural gas in many mills, because that was the
cheapest and most convenient fuel available. However, in most mills it has
been supplemented, at least partially, by oil, and in constructing these
economic profiles we have assumed that all steam raising employs oil as a
fuel source. Because of the relatively small energy requirements of textile
mills, even large integrated mills, it seems unlikely that coal will be used
as a fuel for steam production instead of oil, even if significant further
price increases occur. Similarly, it is very unlikely that natural gas will
be completely supplemented as an energy source, because it is essential with
any of the equipment presently available for fabric drying and heat setting
operations. Even a substantial increase in natural gas prices is unlikely
to change this picture.
The costs of raw materials, labor, and chemicals are not affected by a
change to advanced processing. Fixed costs increase slightly because of
higher investment in the advanced mill. Energy costs are reduced by about
49%, from $144,000 per year to $74,000 per year, but since process energy
costs represent a small amount of the total annual cost (~ 1%), final costs
are hardly affected ($2.45/lb vs. $2.44/lb is certainly within the accuracy
of the estimates).
Pollution control costs (derived in Appendix A) must be added to manu-
facturing 'costs. Wastewater treatment is biological for both base and
advanced case, as specified by the Effluent Limitations Guidelines. (EPA,
41
-------
TABLE IV-5
CAPTIAL AND OPERATING COSTS
INTEGRATED KNIT FABRIC MILL - BASE CASE
Annual Production: 5.5 x 10 Ib/vr
Fixed Investment: $14.1 million
Location: Southeast
Stream Days/Yr: 250 days
VARIABLE COSTS
Raw Materials
Polyester Fiber
Energy
Natural Gas
Steam
Electric Power
Process Water
Cooling Water
Direct Operating Labor
Labor Overhead
Maintenance
Chemicals
TOTAL VARIABLE COSTS
FIXED COSTS
Plant Overhead
Depreciation
Taxes & Insurance
TOTAL FIXED COSTS
TOTAL PRODUCTION COSTS
Return on Investment 20%
TOTAL (ROUNDED)
Units Used in
Costing or
Annual Cost
Basis
Ib
KCF
103 Ib
kWh
103 gal
103 gal
hr
25% labor
2.5Z C.I.
Ib
100Z labor
8.33Z C.I.
1.5Z C.I.
$/Unit
1.10
1.85
4.07
0.019
0.20
0.03
3.30
0.48
Units Consumed
per Ib of
Product
1.03 .
0.0038
0.004
0.018
0.0062
0.0046
0.11
0.39
Annual
Costs
($000)
6231
38
87
19
6.8
0.9
935
235
352
1025
8931
935
1.175
211
2321
11250
2250
13500
$/lb of
Product
1.13
0.007
0.016
0.0003
0.001
0.0001
0.170
0.043
0.064
0.186
1.623
0.170
0.214
0.039
0.422
2.045
0.409
2.45
42
-------
TABLE IV-6
CAPITAL AND OPERATING COSTS
INTEGRATED KNIT FABRIC MILL - ADVANCED CASE
Annual Production: 5.5 x 10 Ib/yr
Fixed Investment: $14.6 million
Locat ion: Southeast
Stream Days/Yr: 250 days
VARIABLE COSTS
Raw Materials
Poylester Fiber
Energy
Natural Gas
Steam
Electric Power
Process Water
Cooling Water
Direct Operating Labor
Labor Overhead
Maintenance
Chemicals
TOTAL VARIABLE COSTS
FIXED COSTS
Plant Overhead
Depreciation
Taxes & Insurance
TOTAL FIXED COSTS
TOTAL PRODUCTION COSTS
Return on Investment 20%
TOTAL (ROUNDED)
Units Used in
Costing or
Annual Cost
Basis
Ib
MCF
H>3 Ib
kWh
103 gal
103 gal
hr
252 Labor
2.5% C.I.
Ib
100% Labor
8.33% C.I.
1.5% C.I.
$/Unit
1.10
1.85
4.07
0.019
0.20
0.03
3.30
0.48
Units Consumed
per Ib of
Product
1.03
0.00037
0.0019
0.25
0.0046
0.11
0.39
Annual
Costs
($000)
6231
4
43
26
5.1
935
235
365
1025
8869
935
1.217
219
2371
11240
2248
13490
$/lb of
Product
1.13
0.0007
0.0079
0.0048
0.0009
0.170
0.043
0.065
0.186
1.610
0.170
0.221
0.039
0.430
2.039
0.408
2.44
43
-------
1974a) These costs are summarized in Table IV-7 and show that pollution
control costs would add 2.5
-------
TABLE IV-8
CAPITAL AND OPERATING COSTS/
INTEGRATED KNIT FABRIC MILL - SOLVENT CASE
Annual Production: 5.5 x 10 Ib/yr
Fixed Investment: $15.5 million
Location: Southeast
Stream Days/Yr: 250 days
VARIABLE COSTS
Raw Materials
Polyester Fiber
Energy
Natural Gas
Steam
Electric Power
Process Water
Cooling Water
Director Operating Labor
Labor Overhead
Maintenance
Chemicals
TOTAL VARIABLE COSTS
FIXED COSTS
Plant Overhead
Depreciation
Taxes i Insurance
TOTAL FIXED COSTS
TOTAL PRODUCTION COSTS
Return on Investment 20%
TOTAL (ROUNDED)
Units Used in
Costing or
Annual Cost
Basis
Ib
MCF
103 Ib
kWh
103 gal
105 gal
hr.
25% labor
2.5% C.I.
Ib
100% labor
8.33% C.I.
1.5% C.I.
\
$/Unit
1.10
1.85
4.07
0.019
0.20
0.03
3.3
0.68
Units Consumed
per Ib of
Product
1.03
0.00037
0.0011
0.12
0.0026
0.11
0.1
Annual
Costs
($000)
6231
4
25
13
1
935
235
387
375
8280
935
1291
232
2458
10738
2148
12810
$/lb of
Product
1.13
0.0007
0.0045
0.0024
0.0001
0.170
0.043
0.071
0.068
1.505
0.170
0.235
0.042
0.447
1.951
0.391
2.33
45
-------
FABRIC PREPARATION
WATER STEAM
PRODUCTION 66.000 LB/DAY - 50:50 POLYESTER/COTTON
WARP YARN
FABRIC TO DYEING
& FINISHING
Figure IV-4. Flow Diagram: Integrated Woven Fabric Mill - Base Case
46
-------
(PRODUCTION - 66,000 #/day)
DYE&
WA
I
EFFLUENTS!
FINISH
TER STE
.
NATL
Gf
i
REAMS
IRAL
IS
AM FABRIC FROM PREPARATION
t
POLYESTER
DYE
DRY&
SET
COTTON
DYE
WASH
DRY
t
1
t
t
FINISH
PAD
HEAT
CURE
-(
\
,) & (Wo) 1,110.000 GAL PROCESS WATER AT 100°F BOD = 1,980 LB
s ^-^ COD = 6,600 LB
TSS = 6,600 LB
V\ 17,700 MCF OF FLUE GAS AT 390°F, POSSIBLY SOME PARTICULATE (LINT)
FINISHED FABRIC
A\ 18,700 MCF OF FLUE GAS AT 390°F, POSSIBLY SOME PARTICULATE (LINT)
17,500 MCF OF FLUE GAS AT 390°F, 66 LB ORGANICS (FROM FINISHING
CHEMICALS) POSSIBLY SOME PARTICULATE (LINT)
Figure IV-5. Flow Diagram: Integrated Woven Fabric Mill - Base Case
47
-------
processing between the two. The first operation is sizing (also called
slashing) of the warp yarn and then drying in preparation for weaving. We
have assumed the use of 100% PVA size, which has been demonstrated in industry,
although much of present-day commercial operation still uses starch size, or a
mixture of starch and synthetic sizes.
After weaving, the cloth is singed - by direct contact with a natural
gas flame, which removes extended fiber ends protruding from the fabric sur-
face - and is then heat set. The cloth is desized by washing with detergent
solution, followed by scouring with caustic, bleaching with hydrogen per-
oxide, and mercerizing w.ith a stronger caustic solution. Each of these steps
has an intermediate wash for the fabric to remove residual chemicals before
proceeding to the next operation. The first wash after the mercerizer con-
sists of diluted but relatively clean caustic solution, which is recycled to
the caustic scour operation. The fabric is then neutralized and dried to
complete the fabric preparation steps. Process water is used in all steps
(except the drying steps and weaving operations) and the effluents from the
washing steps are combined for treatment in a biological treatment system.
Steam is used in most of the processing steps, including the drying steps
which take place on dry cans. Natural gas is used in the singe and heat-set
operations, resulting in a relatively pollution-free flue gas.
After preparation, the sequence of operations (Figure IV-5) is to dye
the polyester using a thermosol pad, followed by drying and heat setting. A
reactive dye is next used to dye the cotton, followed by a washing step and
drying over dry cans. Finish is then applied by padding, followed by the
final heat-set operation in a tenter frame.
The dry and heat-set operations, and the final heat cure, require natural
gas and result in flue gas effluents to the atmosphere. The washing step
after the cotton dyeing produces a wastewater effluent, which is combined
with the wastewater effluents from fabric preparation and sent to the biolo-
gical treatment system. Wastewater from woven-fabric finishing mills contains
natural fiber impurities and processing chemicals from desizing, scouring,
mercerizing, bleaching, dyeing, and finishing.
The desizing process is a major source of BOD and COD. Desizing waste
is also high in dissolved and suspended solids.
Wastewater from scouring and rinsing will contain natural and processing
impurities removed by hot alkaline detergents or soap solution used in scour-
ing. The waste will contain significant levels of BOD, dissolved solids, oil
and grease, and color.
In mercerizing, the caustic soda absorbed by the cloth is recovered and
reused at some large mills. The mercerizing rinse waters are alkaline and
high in dissolved solids. Hydrogen peroxide is generally used for bleaching.
This process contributes little to the waste load; however, the dissolved
solids concentration may be high.
Waste concentrations from dyeing are dependent on the dye and the various
other chemicals used. In addition to color, the waste can contain high
concentrations of BOD and dissolved solids.
48
-------
Finishing chemicals are applied by padding, followed by drying and cur-
ing. The chemicals used are diverse, but only small amounts of them will
enter the wastewater, as the intent is to capture a very high fraction of
the active agent on the cloth.
The combined waste from woven fabric finishing mills will generally
contain 250 to 850 mg/1 BOD, 45 to 475 mg/1 TSS, 425 to 1440 mg/1 COD.
(2) Advanced Case
The advanced processing example shown in Figures IV-6 and IV-7 neces-
sarily uses a very similar sequence of process operations. The most important
process change is the inclusion of a PVA recovery loop, which takes the efflu-
ent stream from the desizing step and (after ultrafiltration) recycles the
concentrated PVA solution back to sizing and the hot water back to the
desizing operation. An additional recycle loop has been added to the wash-
ing steps, and overall water use has been reduced to levels consistant with
the highefficiency equipment. After examination of manufacturers' data, we
concluded that an air/vacuum extractor for drying operations does not offer
a significant advantage for a 50/50 polyester/cotton fabric. As the per-
centage of polyester increases, it becomes more effective and would provide
further energy conservation.
A heat-recovery unit has been integrated with all three tenterframes;
in heatset operations during preparation, after the polyester dyeing, and
for the final heat set of the finish.
h. Energy Consumption
A summary of energy consumption is provided in Table IV-9. The total
electrical energy consumption in the base case is about 19,000 kW and this
has been reduced in the advanced case by about 50%. Steam has been reduced
to 476 million Btu (a decrease of 55%) and natural gas to 146 million'Btu
(a decrease of 70%). In terms of energy consumed at the source, the total
reduction is 57%. The decrease in electrical energy has been achieved by a
reduction in the air-moving requirements to the various tenterframes, although
this is partially compensated by the need for additional electrical energy to
power the PVA recovery system. Steam requirements have been reduced by the
reduction in overall process water use and the recycling of the relatively
clean washwaters to recover their heat values. An advanced type of finish is
also assumed, which requires less water in its application and, therefore, a
reduced heat load on the final heat-cure step. Natural gas requirements for
the tenterframe operations have been considerably reduced by optimization of
the air throughput and the addition of a heat-recovery loop to the system, to
recover waste heat from the flue gases.
c. Economics
A summary of production costs for the base case and advanced processing
of woven fabrics is given in Tables IV-10 and IV-11. The raw materials used,
polyester fiber and cotton, are the same in both cases. Annual energy costs
have Been reduced by about 59%, from $1.33 million to $540,000, and the mix
49
-------
PRODUCTION: 66.000 LB/DAY
FA
WA"
8RICPREPARA7
"ER STE
NAT
G
URAL
AS
ION
AM
FILL YARN
F
WARP YARN
SIZE
i
DRY
' »»
WEAVE
SINGE
HEAT SET
1
DESIZE
WASH
'
CAUSTIC
SCOUR
WASH
PEROXIDE
BLEACH
I
WASH
i
MERCERIZE
1
FRAME
WASH
1
WASH
I
NEUTRALIZE
1
DRY
PVA
^
t
HBR 1C TO DYEING
& FINISHING
PVA
RECOVERY
i >
f(
Figure IV-6. Flow Diagram: Integrated Woven Fabric Mill
Advanced Case
50
-------
DYE AND FINISH
WATER
(PRODUCTION - 66,000 LB/DAY)
STEAM FABRIC FROM PREPARATION
1
1
©& (W^) 384,000 GAL PROCESS WATER AT 100°F BOD = 1,650 LB
^-^ COD = 3,300 LB FINISHED FABRIC
TSS = 6,600 LB
/A\ 6.000 MCF OF FLUE GAS AT 130°F, POSSIBLY SOME PARTICULATE (LINT)
A\ 7,000 MCF OF FLUE GAS AT 130°F. POSSIBLY SOME PARTICULATE (LINT)
A\ 6,000 MCF OF FLUE GAS AT 130°F, POSSIBLY SOME PARTICULATE (LINT)
\7 66 LB HYDROCARBON (FROM FINISHING CHEMICALS)
Figure IV-7. Flow Diagram: Integrated Woven Fabric Mill
Advanced Case
51
-------
TABLE IV-9
SUMMARY OF ENERGY CONSUMPTION - WOVEN FABRIC MILL
(Production, 66,000 Ib/day)
(M
Total
ENERGY CONSUMED IN THE PROCESS
BASE CASE
Preparation
Dyeing
Finishing
Elec-
trical
kWh
6539
6617
5778
Steam
106Btu
711
320
30
Natural
Gas
106Btu
139
210
119
ADVANCED CASE
Elec-
trical
kWh
5644
2268
1929
Steam
106Btu
366
110
Natural
Gas
106Btu
31
101
14
18934
1060
468.
9841
476
146
ENERGY CONSUMED AT SOURCE
Total (rounded)
Elec-
trical
.Steam Nat'l Gas
Elec-
trical
Steam Nat'l Gas
10 Btu equiv.
10PBtu equiv
199
I
2120
2790
468
i
103
I
952
1200
146
l
(57% reduction)
Assumptions:
Electrical Energy 1 kWh = 10,500 Btu. All electrical energy is consumed as mechanical energy.
Steam: 70% boiler efficiency, 20% distribution losses.
Natural Gas: Direct combustion, in the process 100% efficiency
^Electrical energy consumed for weaving, air conditioning, and lighting is excluded.
-------
TABLE IV-10
CAPITAL AND OPERATING COSTS
INTEGRATED WOVEN FABRIC MILL - BASE CASE
Annual Production: 16.5 million Ib/yr
Fixed Investment: $92.6 million
Location: Southeast
Stream Days/Yr: 250 days
VARIABLE COSTS
Raw Materials
Polyester Fiber
Cotton
Energy
Natural Gas
Steam
Electric Power
Process Water
Cooling Water
Direct Operatins Labor
Labor Overhead
Maintenance
PVA Size
Other Chemicals
TOTAL VARIABLE COSTS
FIXED COSTS
Plant Overhead
Depreciation
Taxes & Insurance
TOTAL FIXED COSTS
TOTAL PRODUCTION COSTS
Return on Investment 20%
TOTAL (ROWTSiilJ
Units Used in
Costing or
Annual Cost
Basis
Ib
Ib
MCF
103 Ib
kWh
103 gal
103 gal
hr
25Z labor
2.5Z C.I.
Ib
Ib
100Z labor
8.33% C.I.
1.5Z C.I.
$/Unit
0.51
0.55
1.85
4.07
0.019
0.20
0.03
3.3
0.60
0.36
Units Consumed
per Ib of
Product
0.54
0.54
0.0068
0.015
0.29
0.015
0.20
0.05
0.73
Annual
Costs
($000)
4582
4942
209.2
1035
89.9
52
5016
1254
2412
495
4402.5
24489
5016
7713
1389
14118
38607
7721
46330
$/lb of
Product
0.278
0.300
0.0127
0.063 ,
0.005
0.003
0.304
0.076
0.146
0.030
0.267
1.484
0.304
0.467
0.084
0.856
2.340
0.468
2.81
53
-------
TABLE IV-11
CAPITAL AND OPERATING COSTS
INTEGRATED WOVEN FABRIC MILL - ADVANCED CASE
Location: Southeast
Annual Production: 16.5 million Ib/yr
Fixed Investment: $93.9 million
Stream Days/Yr: 250 days
VARIABLE COSTS
Raw Materials
Polyester Fiber
Cotton
Energy
Natural Gas
Steam
Electric Power
Process Hater
Cooling Water
Direct Operating Labor
Labor Overhead
Maintenance
FVA Size
Other Chemicals
TOTAL VARIABLE COSTS
FIXED COSTS
Plant Overhead
Dpreciation
Taxes & Insurance
TOTAL FIXED COSTS
TOTAL PRODUCTION COSTS
Return on Investment 20%
TOTAL (ROUNDED)
Units Used in
Costing or
Annual Cost
Basis
Ib
Ib
MCF
103 Ib
kWh
103 gal
103 gal
hr
25% labor
1.5% C.I.
Ib
Ib
100% labor
8.33% C.I.
1.5% C.I.
$/Unic
0.51
0.55
1.85
4.07
0.019
0.20
0.03
3.3
0.60
0.41
Units Consumed
per Ib. of
Product
0.54
0.54
0.0023
0.0064
0.15
0.0056
0.20
0.005
0.73
Annual
Costs
($000)
4582
4942
69.1
429.2
46.5
18.4
5016
1254
2347
49.5
4402
23156
5016
7822
1408
14246
37402
7480
44880
$/lb of
Product
0.278
0.300
0.004
0.026
0.003
0.001
0.304
O.»7o
0.142
0.003
0.266
1.403
0.304
0.474
0.086
0.864
2.267
0.454
2.72
54
-------
has been changed away from natural gas. An additional $450,000 is saved by
the recovery of the PVA size, which eliminates 90% of annual PVA costs.
Because the capital investment for installation of the PVA recovery system
is somewhat less than $1 million, the investment for this section of the
plant alone is attractive.
The fixed investment for an annual production of 16.5 million Ib is
estimated to be $92.6 million in the base case and $93.9 million in the
advanced case. (The difference is within the accuracy of the estimates,
but we would anticipate a high investment, because the PVA recovery system
alone costs close to $1 million.)
We also do not anticipate any changes in labor requirements for advanced
processing, so the total fixed costs in both cases are practically the same.
As a result of the lower variable costs, the overall total cost of woven
fabric production is reduced from $2.81/lb to $2.72/lb from the use of
advanced processing.
Water pollution control costs (derived in Appendix A) are based on
biological treatment as specified in the Effluent Guidelines document. (EPA,
1974a) These costs are summarized in Table IV-12, and show that pollution
control would add 2.6c/lb to the base line costs and 1.8£/lb to advanced
processing costs.
TABLE IV-12
WATER POLLUTION CONTROL COSTS FOR INTEGRATED WOVEN FABRIC MILL
Base Line Process Advanced Process
(thousand $) (thousand $)
Capital Investment 714 543
Variable Costs 216 133
Fixed Costs 213 162
Total Annual Cost 429 295
-------
V. IMPLICATIONS OF POTENTIAL PROCESS CHANGES
A. INTEGRATED KNIT FABRIC MILL
Adoption of advanced processing for an integrated knit mill, in spite
of substantially lower energy costs, does not show a marked reduction in over-
all fabric production costs. Therefore, investment in a new plant cannot be
justified solely on economic grounds. However, if it is necessary to replace
processing equipment or install new capacity (or if natural gas is not avail-
able) , then the adoption of advanced processing looks attractive, because the
incrementally higher investment is recouped by lower operating costs and gives
protection against future increases in fuel and water costs. The reduced
water use also reduces pollution control costs and, therefore, stabilizes the
process economics in terms of future, more stringent, pollution control
requirements.
Because overall BOD loads are not reduced appreciably, the pollutant
concentration in the effluent to the biological waste treatment plant will be
higher, but not to the extent that they will adversely affect treatment plant
operation. The quantity of dissolved salts in the effluent will be decreased,
because salts tend to be added in proportion to the water used. Although some
toxic chemicals are used in textile mills - e.g., phenolic compounds, benzidine-
type dyes, chromium compounds - we do not consider their use essential for the
majority of textile mills. Thus, we have assumed that such chemicals are not
used in either base case or advanced processing.
Natural gas is universally used as the fuel for heat-set tenterframes,
because the flue gases come into contact with the fabric. Direct heating with
oil cannot be used in present equipment, because sulfur compounds and other
impurities would affect product quality. Indirect heating of tenterframes
by superheated steam or heat-transfer fluids appears feasible, but the equip-
ment is not commercially available. Direct heating with natural gas allows
continuous combustion of lint particles which are removed from the fabric.
In an indirectly heated system, these particulates would tend to build up in
the unit and reduce operating efficiency. Other penalties of an indirect
heating system would be decreased efficiency, higher capital cost, and higher
fuel cost (for fuel oil, because coal would be impractical for most textile
mills). In summary, we believe that the textile industry will continue to
need* natural gas for these operations even with gas at a premium price.
In terms of incremental investment, an increase of $500,000 to achieve
advanced processing is recouped to the extent of $100,000 annually from
reduced total cost, which provides an attractive payback period of less
than five years. All the technology is available and has been commercially
demonstrated at some point in the textile industry.
56
-------
The technology for all-solvent processing is not yet commercially
demonstrated, although equipment is available and certain operations (such
as solvent scouring) are well demonstrated and commercially used in certain
parts of the knit-fabric industry for a variety of synthetic fabrics. How-
ever, dyes for solvent dyeing have not been sufficiently well developed to be
widely acceptable, and though much laboratory data is available, solvent
dyeing is not practiced on a commercial scale. Assuming that all-solvent
dyeing can be established, then solvent washing would appear to be possible,
leading to an all-solvent system. This would virtually eliminate the process
water effluent which needs biological treatment, but would instead produce a
potential air pollution problem from the escape of solvent and require appro-
priate solvent recovery systems. However, such systems are within the state
of the art and are sold as packaged units with the solvent-scouring systems
presently in use. Because of the present concern over chlorinated solvents,
some additional recovery may be required to meet future, more stringent, air
pollution control regulations. An all-solvent system would also generate a
minor proportion of solid waste for disposal.
Overall costs for the solvent case are quite attractive ($2.33/lb versus
$2.45/lb for the base case). There also is a further savings in energy costs
over that achieved in advanced processing, but the incremental investment of
$1.1 million is only offset by a reduction of about $30,000 in utility costs.
However, we believe that there is a potential further reduction of up
to $650,000 in chemical costs, though the technology has yet to be demon-
strated. Air pollution control costs are carried as part of overall production
costs, because solvent distillation and recovery units are sold as a package
with the process equipment.
B. INTEGRATED WOVEN FABRIC MILL
The adoption of advanced processing for woven fabrics shows a signifi-
cant lowering of overall production costs compared to the base line case
(from $2.81 to $2.72). Adoption of advanced processing is likely to occur
where new or replacement capacity is required, because the incremental savings
over new capacity using base case technology are substantial. (An incre-
mental investment of $1.3 million produces annual savings of $800,000.) The
PVA recovery loop shows substantial economic savings from the reuse of the
PVA size, and this is being installed in existing mills. However, at present,
the technology is only applicable where PVA size is being used exclusively,
and it must still be demonstrated that PVA size can be applied to the wide
variety of fibers and products being processed in the textile industry.
The reduced water use for advanced processing will reduce treatment plant
size and costs. PVA recovery and reduced chemicals use will also reduce
pollution loads. Increased pollutant concentrations will not be sufficient to
cause problems in biological treatment.
57
-------
REFERENCES
American Permac Inc., "Finishing in Solvent," Manufacturers Data,
Garden City, N. Y.
C.A. Brandon, A. El Nasher. and J.P. Porter, "Hyperfiltration Pilot Plant
For Textile Wastewater Renovation," Am. Dyestuff Rep., p. 20, Oct. 1975.
Byland, H.R., Capponi, M., Gerber, H., and Somm, F., "Application of Dyeing
Principles from Organic Solvents in Continuous Dyeing," JAATCC. 3. 33, 1971.
Jesse G. Camp, Jr., Gaston County Dyeing Machine Co., personal communication.
U.S. Dept. of Commerce, U.S. Industrial Outlook 1975, U.S. Government
Printing Office, Washington, D.C., 1974.
U.S. Dept. of Commerce, U.S. Industrial Outlook 1976, U.S. Government
Printing Office, Washington, D.C., 1975.
U.S. Environmental Protection Agency, Textile Mills (Development Document
for Effluent Limitations Guidelines and New Source Performance Standards)
EPA 440/l-74-022a, June 1974a.
U.S. Environmental Protection Agency, "In-Plant Control of Pollution,"
EPA 625/3-74-004, October 1974b.
U.S. Environmental Protection Agency, "Treatment and Reuse of Textile
Dyehouse Wastewaters Using Reverse Osmosis," EPA Demonstration Project
800929 to LaFrance Industries, S.C.
Gaston County Dyeing Machine Co., "The Reuse of Polyvinyl Alcohol in
Textile Processing," presented at Clemson, S.C., July 30, 1974a.
Gaston County Dyeing Machine Co., The Gaston County Alternator Washer,
Manufacturers Brochure, Stanley, N.C., brochure a.
Gaston County Dyeing Machine Co., The Gaston County H-Series Jet Dyer,
Stanley, N.C., brochure b. i
i
Gaston County Dyeing Machine Co., personal communication.
Hofstetter, H.H., "Solvents in Textile Processing," Textile Industries,
p. 53, June 1970.
58
-------
Institute of Textile Technology and Hydroscience, Inc., report for the
American Textile Manufacturers Institute, Jan. 15, 1973.
Lockewood Green Engineers, Inc., Textile Industry, Technology and Costs of
Wastewater Control, prepared for National Commission on Water Quality, 1975.
Reinhart, R.M., and Reid, J.D., "Solvent Technology Update," AATCC
Symposium, Atlanta, January 1973.
Willard, J.J., "Solvent Processing in the Textile Industry," p. 43, AATCC
Symposium.
Zeiffer, D., Gaston County Dyeing Machine Co., "Extraction Capability and
Economics of Gaston County Vacuum Roll Extractor," paper.
1972 Census of Manufactures, Textile Products.
International Textile Machinery, "Continued Evolution in Dyeing and
Finishing," p. 125, 1975.
"Solvent Dyeing of Cellulosic Fibers," JAATCC 5, 60, March 1973.
Textile Industries, "Solvent and Hot Melt Slashing," p. 30, January 1973.
Textile Industries, "Stevens Reclaims PVA for Warp Sizing" Staff Report,
p. 47, October 1974.
Textile Industries, "Machinery Designed to Save Energy," 197, May 1975.
Textile Industries, "Progress in Radiation Processing," A Staff Report,
p. 83, November 1975.
Textile Industries, Jawtex unit descriptor, p. 91, Dec. 1975.
Textile Industries, Kleinewefers "100 plus" description, p. 88, Dec. 1975.
"Textile Industry and the Environment," Washington, D.C., May 1973.
Textile World, "Whitaker's Vacuum Impregnator Scores," p. 105, December 1972.
59
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APPENDIX A
CURRENT POLLUTION PROBLEMS AND EFFECTIVENESS
OF AVAILABLE POLLUTION CONTROL TECHNOLOGY
The textile industry is involved in many different kinds of processing.
This report has defined energy-conserving process options in terms of an
integrated knit fabric mill and an integrated woven fabric mill. An inte-
grated mill is a combination of a greige fabric mill and a finishing mill,
so in terms of pollution control technology this includes three categories
defined in the Effluent Guidelines Limitations:
Category 3 - Dry Processing
Category 4 - Woven Fabric Finishing
Category 5 - Knit Fabric Finishing
Pollution control problems in the textile industry are concentrated in
the wastewater effluent. Air pollution problems and solid waste disposal
problems are minimal. Therefore, major emphasis has been given to water-
related environmental problems.
I. WATER-RELATED ENVIRONMENTAL PROBLEMS
a. Wastewater Sources
Wastes at greige mills constitute residues in size boxes at the end of a
day or a week, and water used for cleanup. The volumes of textile wastes in
a greige mill are small. Significant amounts of cooling water used in a greige
mill may not require waste treatment. Wastes associated with finishing woven
goods result from removal of foreign material during the cleaning and bleaching
of cotton polyester blends and from the various chemicals used in finishing
the fabric.
(1) Desizing
Polyvinyl alcohol (the size agent chosen for the base line case), is
removable with a detergent/water solution. Desizing these materials will thus
contribute suspended solids, dissolved solids and oil and grease. Desizing
may contribute 50% or more of the total waste solids in a woven goods finishing
mill. Polyvinyl alcohol has been considered only slowly biodegradable, and,
60
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as such, is a major source of COD. Recent studies performed by producers of
polyvinyl alcohol, in cooperation with textile mills, indicate that biological
waste systems will develop organisms acclimated to polyvinyl alcohol, and
when this has occurred, biodegradation is relatively rapid and complete.,
(2) Scouring
The major chemical used in scouring cotton - caustic soda - appears in
the waste stream. A surfactant and a small amount of sodium phosphate are
frequently used, and these also appear in the waste stream. The wastes will
also contain cotton waxes (about 3-4% of the cotton used). Consequently,
scouring liquors are strongly alkaline (pH greater than 12), and dark colored
due to cotton impurities. They contain significant levels of dissolved solids
and oil and grease. A modest level of suspended solids results from the
presence of cotton impurities. The natural cotton impurities removed from
greige fabric by scouring contribute BOD and are biodegraded rapidly.
(3) Mercerization
Mercerization wastes are predominatly the caustic alkali used in the
process. The waste stream contains high dissolved solids, and again may have
a pH of 12 to 13. BOD level is low, and is due to penetrant used as an
auxiliary with the caustic. Small amounts of foreign material and wax may be
removed from the fiber and will appear as suspended solids; these materials
will contribute a small BOD load.
In large mills, caustic soda is recovered and concentrated for reuse
thus saving chemical and avoiding a sizeable waste load. Estimates have
indicated that recovery of mercerizing caustic is justified when the caustic
use is more than 5 million pounds per year (dry), and concentration of alkali
is not permitted to fall below 2%.
(4) Bleaching
Bleaching with hydrogen peroxide contributes very small waste loads,
most of which are dissolved solids. The dissolved solids are both inorganic
(sodium silicate, sodium hydroxide and sodium phosphate) and organic (a
surfactant and chelating agent). The waste stream contains some suspended
solids when goods containing cotton are bleached.
(5) Dyeing
Dyeing processes contribute substantially to textile wastes. Color is
a visible problem. A high level of dissolved solids is expected. Suspended
solids should be low. Carriers, which are essential for dyeing polyester, and
acetic acid, have high BOD. With thermosol dyeing of cotton/polyester blends,
carriers may be avoided, thus reducing BOD and COD loads.
61
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(6) Finishing
Wastes from resin treatment, water-proofing, flame-proofing, and soil
release are small, because the chemicals are applied by padding, followed by
drying and curing. The chemicals used are diverse and small amounts of them
will enter the wastes.
The main differences between knit and woven-fabric wet-processing opera-
tions are that knit yarns are treated with lubricants rather than with the PVA
sizes used for woven goods yarns, and that mercerizing operations are not
employed with knit goods. Otherwise, the character of the wastes generated
from comparable unit operations performed on different fibers - cottons,
synthetics, and blends - are similar to those found in woven-fabric finishing.
Lubricating finishes applied to knitting yarns generally are based on
mineral oils, vegetable oils, synthetic ester-type oils, or waxes, and may
also contain antistatic agents, antioxidants, bacteriostats, and corrosion
inhibitors. Specific formulations are proprietary with the yarn supplier or
throwster who applies the finish. The amount applied varies with the type of
yarn; general levels of add-on by weight-percent on yarn are: untexturized
synthetic yarns, l-2#; t'exturized synthetic yarns, 4-7%; and cotton yarns
3% or less. The knitting oils are readily emulsified or soluble in water,
and are removed to the wastewater by washing prior to the dyeing operation.
b. Wastewater Characterization, Woven Fabrics - Base Case
The combined wastewater streams contain a mixture of inorganic salts
(mainly sodium chloride, sodium sulfate, and some sodium acetate), polyvinyl
alcohol (PVA), caustic soda, biodegradable detergents, excess dyestuffs, and
suspended solids that are mostly short, non-reusable fibers and a small
amount of insoluble dye. The detergents constitute the principal BODc load,
while PVA is the major source of COD. Note, however, that PVA is substan-
tially biodegradable in an "acclimatized" treatment plant, although it does
not indicate an appreciable BOD5 in a standard test using unconditioned
microorganisms.
Figures IV-4 and IV-5 show the wastewater flow streams occurring from the
woven fabric mill, (greige manufacturing and finishing).
c. Wastewater Characterization, Woven Fabrics - Advanced Aqueous
The total hydraulic load is reduced to about one third the value used
for the base case example by conservation and reuse. With more efficient
washing, detergent decreases about 15-20% , thereby lowering the BOD5 load
on the treatment plant. In addition, the use of PVA recovery techniques
will reduce COD by about 50%. We have assumed a small bleed of the PVA
stream to the waste treatment plant to maintain it biologically acclimatized
to PVA. Other chemical use will be similar to the base line example.
Figures IV-6 and IV-7 show the expected wastewater flows from the woven-
goods advanced aqueous example.
62
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d. Wastewater Characterization, Knit Fabrics - Base Case
The combined wastewater streams contain a mixture of inorganic salts
(sodium chloride and sulfate, principally), knitting oil, biodegradable
detergent, suspended solids that are mostly excess disperse dye and dye
carriers.
The detergents and knitting oils are the primary contributors to the
BOD5 values, along with the dye carriers. The dye carriers tend to show high
COD in standard tests, but are often satisfactorily treated in a conditioned
secondary waste treatment plant. Knitting oils also require acclimatized
microorganisms for satisfactory biological treatment.
Figure IV-1 shows the wastewater effluents from the knit-fabric mill,
base case (greige manufacturing and finishing).
e. Wastewater Characteristics, Knit Fabrics - Advanced Aqueous
Figure IV-2 shows the expected wastewater flows from the knit goods
advanced aqueous example. The hydraulic load is reduced to one third of that
postulated for the base line example, with possible small reduction in BOD5,
COD, and suspended solids.
f. Wastewater Characteristics, Knit Fabrics - Solvent Processing
The wastewater effluent from all solvent processing of knit goods will
be essentially zero. A minor quantity of polluted water from the steam con-
densate may exist, which can be treated by solid waste disposal techniques
or possibly discharged to municipal treatment (see Figure IV-3).
g. Existing Regulatory Constraints
Water pollution regulatory constraints imposed on the manufacture of
textile fabrics are mainly the result of Sections 304 (b) and 306 of the
Federal Water Pollution Control Act, as amended. The Act provides for the
United States Environmental Protection Agency to issue effluent limitations
guidelines applicable to the point-source discharge of industrial wastewater.
The effluent limitations guidelines for Textile Mills is based on the "EPA
Development Document" pertinent to that industry (EPA-440/l-74-022a, 1974).
The Development Document is a technical study that characterizes the
industry, describes the sources of water pollution, and presents suggested
permissible effluent levels based on recommended technology and its associ-
ated cost. The effluent limitations guidelines, based on the Development
Document and supplemented by EPA and industry review and comment, forms the
basis from which actual discharge permits are negotiated.
63
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The effluent limitations guidelines set forth three effluent discharge
levels for the manufacture of textiles:
BPCTCA - Best Practicable Control Technology Currently Available
(to be implemented by 1977);
BATEA - Best Available Technology Economically Achievable (to be
implemented by 1983); and
Standards of Performance for New Sources (applicable to new plants
built between 1977 and 1983; after 1983 the BATEA level applies).
The pollutional parameters which have been deemed necessary to set
specific regulations for are:
5-day biochemical oxygen demand (BOD_),
Chemical oxygen demand (COD),
Total suspended solids (TSS),
Total chromium,
Phenol,
Sulfide,
Fecal coliform, and
Color.
The effluent limitations, as published in the Development Document, are
in terms of weight of the specific pollutant per unit weight of production
and are presented in Tables A-l and A-2.
h. Recommended Wastewater Treatment Technology
To achieve the effluent levels stipulated in the effluent guidelines, we
have accepted the treatment steps recommended in the Development Document and
in the Economic Analysis of Effluent Guidelines, Textile Industry, EPA-230/2-
75-028 dated June 1975. These treatment steps are shown in Figures A-l and
A-2. We have assumed the full Level II Treatment in costing our example
processes.
i. Wastewater Treatment Costs
The wastewater treatment plant costs were calculated based on the method-
ology used in EPA-230/2-75-028, Economic Analysis of Effluent Guidelines,
Textile Industry, dated June 1975, updated to mid-1975 using the ENR Cost
Index. The results are shown in Tables A-3 and A-4.
64
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TABLE A-l
EFFLUENT LIMITATIONS REQUIREMENTS - WOVEN FABRIC FINISHING
Effluent Average of Daily Values for 30 Consecutive Days
Characteristics ' shall not exceed
BOD5
COD
TSS
Total Chromium
Phenol
Sulfide
Fecal Coliform
Color --- 300
Except for fecal colifonn, the maximum limitations for any one day should not
exceed these 30-day limitations by more than 100%.
TABLE A-2
EFFLUENT LIMITATIONS REQUIREMENTS - KNIT FABRIC FINISHING
Effluent Average of Daily Values for 30 Consecutive
Characteristics Days, shall not exceed!
BPCTCA
3.3
30-60
8.9
0.5
0.5
0.10
(kg/103 k
BATEA
2.2
10-20.2
1.5
0.05
0.05
0.10
, MPN
g product)
NSPS
3.3
30-60
3.3
0.05
0.05
0.10
(kilograms
BPCTCA
2.5
30-50
10.9
0.05
0.05
0.10
per 1000 kg of
BATEA
1.7
10-16.7
1.7
0.05
0.05
0.10
MPN
400 100ml
product)
NSPS
2.5
30-50
2.5
0.05
0.05
0.10
BODg
COD
TSS
Total Chromium
Phenol
Sulfide
Fecal Coliform
Color 300
Except for fecal coliform, the maximum limitations for any one day should
not exceed these 30-day limitations by more than 100%.
65
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RAW WASTEWATE R
PRIMARY SCREENING
AERATION
STABILIZATION
BASIN
THREE-DAY
NON-AERATED
LAGOON
FINAL DISCHARGE
Figure A-l. Schematic Flow Diagram of Process Steps
and Cost Centers for Level I Treatment
66
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RAW WASTE WATER
PRIMARY SCREENING
AERATION
STABILIZATION
BASIN
[ CLARIFIER j
o
LLJ
CC
UJ
CD
Q
_l
w
LIME
TREATMENT
MULTI-MEDIA
FILTRATION
FINAL DISCHARGE
Figure A-2.
Schematic Flow Diagram of Process Steps
and Cost Centers for Level II Treatment
67
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TABLE A-3
POLLUTION CONTROL COSTS - WOVEN FABRIC MILL
Advanced
Base Case Aqueous Processing
Capital Investment $714,000 $573,000
Fixed Costs
Depreciation @8.3Z 59,300 45,100
ROI (§20% 142,800 108,600
Taxes & Insurance @1.5% 10,700 8.200
212,800 161,900
Variable Costs
Operating Labor (Incl.overhead) 43,300 52,000
Maintenance, Labor & Supplies 18,600 18,600
Chemicals 54,100 21,400
Energy 99,800 40,800
Total Annual Cost $428,600 $294,700
Basis: Production (kg/day) 30,000 30,000
Hydraulic Load (kg/day) 4210,000 1450,000
Pollution Load: BOD5(kg/day) 900 750
COD (kg/day) 3,000 1,500
TSS (kg/day) 3,000 3,000
68
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TABLE A-4
POLLUTION CONTROL COSTS - KNIT FABRIC MILL
BASE CASE
$ 288,800
FIXED COSTS
Depreciation @ 8.33%
Tax and Insurance @ 1.5%
ROI @ 20%
Total Fixed Costs
24,000
4,300
57.800
$ 86,100
ADVANCED AQUEOUS
PROCESSING
$ 170,500
14,200
2,600
37.100
$ 50,900
VARIABLE COSTS
Operating Labor
Maintenance, Labor and Supplies
Chemicals
Energy
Total Variable Costs
TOTAL ANNUAL COST
$
$
$
35,
11,
1,
48,
134,
400
500
900
000
800
900
$
$
$
24,300
8,500
300
1,000
34,100
85,000
Basis:
Production (kg/day)
Hydraulic Load (kg/day)
Pollution Load: BOD (kg/day)
COD (kg/day)
TSS (kg/day)
10,000
516,000
250
800
80
10,000
171,000
250
800
80
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2. AIR-RELATED ENVIRONMENTAL PROBLEMS
Air pollution from textile mills is relatively minor and consists of low
levels of particulates, such as lint, and a small amount of organic from
the finishing chemical used, which is exhausted with the flue gases from heat-
set tenterframes. We estimate that the amount emitted (66 Ib/day from the
model woven-fabric mill; 22 Ib/day from the model knit-fabric mill) is below
the level which would require air pollution controls.
Adoption of advanced aqueous processing will not materially affect air
emissions from woven-fabric mills or knit-fabric mills. Solvent processing
of knit fabrics is a different situation, because of the potential emissions
of chlorinated hydrocarbons, trichlorethylene, and perchlorethylene. The
commercially available equipment for solvent processing incorporates solvent
recovery as part of the equipment for economic reasons, and it is claimed
that the emissions of solvents are less than 3% of the weight of fabric
processed. This level may be satisfactory for a small amount of solvent
scouring, but for an all-solvent knit mill, processing 22,000 Ib/day, it
would result in emissions of 660 Ib/day of perchlorethylene solvent. We
have assumed in the model that emissions will be 1% of fabric weight (220 lb/
day). Further development work is clearly necessary to define an acceptable
level and to develop control technology to control solvent emissions.
3. SOLID WASTE-RELATED PROBLEMS
Solid, wastes are not a big problem in the textile industry. One source
consists of waste fiber in short lengths which accumulates on and around the
machinery or is filtered out in the waste-treatment system. This material is
usually stored and periodically disposed of to landfill.
A second, source is the tarry residues .that gradually accumulate in the
heat-set tenterframes. These residues consist of degradation products from
finishing chemicals and periodically the tenterframes are shut down so that
they can be removed manually.
Adoption of solvent processing will result in a solid waste from the
solvent recovery system containing hydrocarbons, such as knitting oils, with
smaller amounts of dyes and finishing chemicals. This will be removed daily
for incineration or landfill.
70
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APPENDIX B
GLOSSARY
acetate - A manufactured fiber made of cellulose acetate.
acrylic - A manufactured fiber in which the fiber-forming substance is any
long-chain synthetic polymer composed at least 85% by weight of acrylonitrile
units. Made in both filament and staple form, (e.g., Acrilan, Orion, Creslan.)
advanced processing - An assembly of unit operations in a knit or woven
fabric mill which are designed to minimize water and energy use.
beck - A chamber in which goods may be scoured and dyed. May be operated at
atmospheric pressure or at elevated temperature and pressure.
biphenyl (or diphenyl) - A carrier used in dyeing polyester.
biochemical oxygen demand (BOD) - A method of measuring rate of oxygen usage
due to biological oxidation. A BOD5 of 100 mg/liter means that a sample
(1 liter) used 100 mg of oxygen in 5 days.
biological treatment - The use of biological organisms in a waste treatment
system (similar to those used in a municipal sewage system) to achieve reduc-
tions in pollutants before discharge.
bleaching - Removal of colored components from a textile. Common bleaches
are hydrogen peroxide, sodium hypochlorite, and sodium chlorite.
blend - The combination of two or more types of fibers and/or colors in one
yarn.
butyl benzoate - A carrier used in dyeing polyester.
carrier - An organic material used in dyeing polyester. (See biphenyl, ortho-
phenyl, phenol, trichlorobenzene, butyl benzoate.)
caustic soda - A strong alkali used, for example, in mercerizing.
cellulose - Major component of cotton and rayon. Also used as the base for
acetate fiber.
chemical oxygen demand (COD) - The amount of oxygen required to oxidize
materials in a sample by means of a dichromate solution.
71
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chlorinated solvents - Organic hydrocarbons containing chlorine in the
molecule; e.g., perchloroethylene, which is used in drycleaning and in
some textile operations.
commission finishers - Mills that dye and finish textile fabrics owned by
others. (A "legal" definition of commission finishers is given in the
Development Document for Effluent Limitations Guidelines, EPA-440/l-74-022-a.)
crease-resistant - Fabrics that have been treated to make them resistant to
wrinkling. One of the most common methods is to incorporate a resin.
desize - Removal of size. Several methods may be used. (See enzyme.)
developed dye - An azo dye whose color is developed by reaction on cotton.
diphenyl - (See biphenyl.)
direct dyes - Class of dyestuffs that colors cellulosic fibers in full shades.
disperse dye - A type of dye used to color several synthetic fibers. Applied
as a fine dispersion using a carrier. On cloth, padded dye may be baked on
or "thermofixed."
dissolved solids - Total solids - suspended solids in a sample of wastewater.
double knit - Knitted fabric made on a special knitting machine that combines
a double set of needles to produce a fabric.
durable press - Goods that require no ironing during the normal use-life of a
garment. The term applies to apparel and other textile products such as
sheets, draperies, etc. As a rule, DP is achieved in two ways: 1. Pre-
curing fabrics with a special resin finish then pressing made-up garment.
2. Post-curing fabric with a resin finish then cooking made-up garments in
an oven. As a rule, polyester-cotton blends are used, but there are 100%
cottons, and other blends also.
enzyme - An agent used to remove starch size.
greige - Fabrics in unbleached, undyed state before finishing. In the United
States, called "gray goods" or "grey goods."
heat setting - Application of heat to the fabric in a tenterframe at tempera-
tures of 340°-400°F, with or without additional chemicals to impart to the
fabric desirable and permanent characteristics.
hydraulic load - The volume rate of polluted water in gallons per day (gpd)
which is sent to the biological (or other) treatment plant. Sometimes
expressed as gal per pound of fabric processed.
72
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kier - A piece of equipment in which cotton is boiled with dilute caustic soda
to remove impurities. Also used as a verb to describe the process.
knitting - Process of making fabric by interlocking series of loops of one or
more yarns. Types are: jersey (circular knits), tricots (wrap knits), double
knits.
mercerizing - Finish used on cotton yarns and fabrics to increase luster,
improve stretch and dyeability. Treatment consists of impregnating fabrics
with cold, concentrated sodium hydroxide solution.
modacrylic - Generic name established by the Federal Trade Commission for a
"manufactured fiber in which the fiber-forming substance is any long-chain
synthetic polymer composed of 35-85% by weight of acrylonitrile units."
naphthol dye - An azo dye whose color is formed by coupling with a naphthol.
Used chiefly on cotton.
nylon - Generic name for a manufactured fiber in which the fiber-forming
substance is any long-chain synthetic polyamide having recurring amide groups
as an integral part of the polymer chain.
ortho phenyl phenol - A carrier used in dyeing polyester.
perchloroethylene - A chlorinated solvent which has been widely used in dry-
cleaning establishments and in solvent scouring of knit goods.
permanent finish - Fabric treatments of various kinds to improve glaze, hand,
or performance of fabrics. These finishes are durable to laundering.
pH scale - A method used to describe acidity or alkalinity: pH 7 is neutral;
from 0-7 is acid; 7-14, alkaline. The scale extends from 0 to 14 and a change
of 1 unit represents a tenfold change in acidity or alkalinity.
polyamide - (See nylon.)
polyester - A manufactured fiber in which the fiber-forming substance is any
long-chain synthetic polymer composed of at least 85% by weight of an ester
of dihydfic alcohol and terephthalic acid.
polypropylene - Basic fiber-forming substance for an olefin fiber.
«i
precured fabric - Technique for imparting durable press by impregnating fabrics
with special resins then curing same. Does not require oven after-treatment
of apparel. (See durable press.)
post-cured - Technique for imparting durable press that requires baking apparel
in ovens to cure fabrics that have been impregnated with special resins. Most
common technique used with polyester and cotton blends. (See durable press.)
73
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rayon - A generic name for man-made fibers, monofilaments, and continuous
filaments, made for regenerated cellulose. Fibers produced by both viscose
and cuprammonium process are classified as rayon.
reactive dyes - Dyes that react chemically with the fiber.
resin - A chemical finish used to impart a property desired in a fabric, such
as water repellency or hand, etc. (See durable press.)
scouring - Removal of foreign components from textiles. Normal scouring
materials are alkalies (e.g., soda ash) or trisodium phosphate, frequently
used in the presence of a surfactant. Textile materials are sometimes
scoured by use of a solvent.
sequestrant - A chemical used to bind foreign metal ions. Frequently used in
dyeing. A common sequestrant is EDTA.
size - A material applied to warp yarns to minimize abrasion during weaving.
Common sizes are starch, polyvinyl alcohol (PVA), and carboxymethyl cellulose.
Sizes are applied continuously in a slasher.
softener - A chemical used to apply a soft, pleasant hand. Fat derivatives
and polyethylene are common softeners.
solution-flyed - Synthetic fibers sometimes are dyed by adding color to the
chemical polymer before fibers are formed. Also called dope dyed.
solvent processing - An assembly of unit operations in which a solvent such
as perchloroethylene is used instead of water to transfer chemicals to and
from the fabric.
standard raw waste load (SRWL) - A description of the properties of wastewater
before treatment.
starch - Organic polymer material used as a size; highly biodegradeable.
sulfur dye - A class of dyes that dissolve in aqueous sodium sulfide forming
products with a marked affinity for cotton; the dyes are regenerated by air
oxidation.
suspended, solids (TSS) - Amount of solids separated by filtration of a sample
of wastewater.
tenterframe - A driven-chain machine that maintains dimensional stability of
fabric being processed. (See heat setting.)
textured - Bulked yarns that have greater volume and surface interest than
conventional yarn of same fiber.
74
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total organic content (TOC) - The total organic materials present in a
sample of wastewater.
total oxygen demand (TOD) - The amount of oxygen necessary to completely
oxidize materials present in a sample of wastewater.
total solids - Amount of residue obtained on evaporation of a sample of
wastewater.
triacetate - Differs from regular .cellulose acetate, which is a diacetate.
The description implies the extent of acetylation and degree of solubility
in acetone.
tricot - Warp-knitted fabric. Tricots are flat knitted with fine ribs on the
face (lengthwise) and ribs on the back (widthwise).
tufted fabric - Fabric decorated with tufts of multiple ply yarns. Usually
hooked by needle into fabric structure. Used widely for carpets.
vat dye - A type of dye applied from a liquor containing alkali and a power-
ful reducing agent, generally hydrosulfite. The dye is subsequently oxidized
to the colored form. Widely used on cellulosic fibers.
warp - Set of lengthwise yarns in a loom through which the crosswise filling
yarns (weft) are interlaced. Sometimes called "ends."
weaving - The process of manufacturing fabric by interlacing a series of
warp yarns with filling yarns at right angles.
yarn - An assemblage of fibers or filaments, either manufactured or natural,
twisted or laid together so as to form a continuous strand which can be used
in weaving, knitting, or otherwise made into a textile material.
yarn-dyed - Fabrics in which the yarn is dyed before weaving or knitting.
75
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
i. REPORT NO.
EPA-600/7-76-0341
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
ENVIRONMENTAL CONSIDERATIONS OF SELECTED ENERGY CON-
SERVING MANUFACTURING PROCESS OPTIONS. Vol. IX.
Textile Industry Report
5. REPORT DATE
December 1976 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
3. PERFORMING ORGANIZATION NAME AND ADDRESS
Arthur D. Little, Inc.
Acorn Park
Cambridge, Massachusetts 02140
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-03-2198
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
FINAL
14. SPONSORING AGENCY CODE
EPA-ORD
is. SUPPLEMENTARY NOTES Vol. m-vill, EPA-600/7-76-034c through EPA-600/7-76-034h, and X-
XV, EPA-600/7-76-034J through EPA-600/7-76-034J through F,PA-600/7-76-034o, refer to
studies of other industries as noted below; Vol. I, EPA-600/7-76-034a is the Industrv
16. ABSTRACT
Summary Keport and Vol. II, EPA-600/7-76-034b is the Industrv Primary
J Report.
This study assesses the likelihood of new process technology and new practices being
introduced by energy intensive industries and explores the environmental impacts of
I such changes.
Specifically, Vol. IX deals with the textile industry and examines the environmental
energy and economic impacts of three "model" technologies: (1) integrated knit
fabric mill using "advanced" processing of 100% polyester fiber, (2) integrated knit
fabric mill using solvent processing of 100% polyester fiber, and (3) integrated
woven fabric mill using advanced processing of 50/50 polyester cotton fiber mixture,
all in comparison with a "base line" technology representing the best of present
textile industry practice. Vol. III-VIII and Vol. X-XV deal with the following
industries: iron and steel, petroleum refining, pulp and paper, olefins, amonia,
aluminum, cement, glass, chlor-alkali, phosphorus and phosphoric acid, copper, and
fertilizers. Vol. I presents the overall summation and identification of research
needs and areas of highest overall priority. Vol. II, prepared early in the study,
presents and describes the overview of the industries considered and presents the
methodology used to select industries.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Energy
Pollution
Industrial Wastes
Textiles
Manufacturing Processes;
Energy Conservation;
Blend Fabrics; Solvent
Finishing; Dyeing;
Finishing
13B
13. DISTRIBUTION STATEMENT
Release to public
19. SECURITY CLASS (ThisReport)'
unclassified
21. NO. OF PAGES
90
20. SECURITY CLASS (Thispage)
unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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