United States
                          Environmental Protection
                          Agency
            Risk Reduction
            Engineering Laboratory
            Cincinnati, OH 45268
                          Research and Development
            EPA/600/S-94/006   September 1994
                          ENVIRONMENTAL
                          RESEARCH   BRIEF
                 Waste Minimization Assessment for a Manufacturer
                                     of Prewashed Jeans

                              Richard J. Jendrucko*, Thomas N. Coleman*,
                                        and Gwen P. Looby**
Abstract
The U.S. Environmental Protection Agency (EPA) has funded
a pilot project to assist small and medium-size manufacturers
who want to minimize their generation of waste but who lack
the expertise to do so. In an effort to assist these manufactur-
ers Waste Minimization Assessment Centers (WMACs) were
established  at selected  universities, and procedures  were
adapted from the EPA Waste Minimization Opportunity As-
sessment Manual (EPA/625/7-88/003, July 1988). That docu-
ment has been superseded by the Facility Pollution Prevention
Guide (EPA/600/R-92/088, May 1992). The WMAC team at the
University of Tennessee performed an assessment at a plant
that prewashes denim jeans prior to retail sale. Predyed jeans
are  received from other facilities and washed. An abrasive
material is used in some of the wash loads. Some of the jeans
are processed in tumblers in order to give the jeans a faded
look. After processing, the jeans are dried, inspected, mended,
pressed,  packaged, and shipped. The assessment team's re-
port,  detailing findings and recommendations, indicated that
the waste generated in the greatest quantity is wastewater
from  the washers and  tumblers  and that the greatest cost
savings  could be realized by  installing an  onsite wastewater
treatment plant.

This Research Brief was developed by the  principal  investiga-
tors and EPA's Risk Reduction Engineering  Laboratory, Cincin-
nati, OH, to announce  key findings of an ongoing research
project that is fully documented in a separate report of the
same title available from University City Science Center.
* University of Tennessee, Department of Engineering Science and Mechanics.
"University City Science Center, Philadelphia, PA.
Introduction
The amount of waste generated by industrial plants has be-
come an increasingly costly problem for manufacturers and an
additional stress on the environment. One solution to the
problem of waste generation is to reduce or eliminate the
waste at its source.

University City Science Center (Philadelphia, PA) has begun a
pilot project to assist small and medium-size manufacturers
who want to minimize their generation of waste but who lack
the in-house expertise to do so. Under agreement with EPA's
Risk Reduction Engineering Laboratory, the Science Center
has established three WMACs. This assessment was done by
engineering  faculty  and  students at the University of
Tennessee's (Knoxville) WMAC. The assessment teams have
considerable direct experience with process operations in manu-
facturing plants and also have the knowledge and skills needed
to minimize waste generation.

The waste minimization assessments are done for small and
medium-size  manufacturers at no out-of-pocket cost to the
client. To qualify  for the assessment,  each client must fall
within Standard Industrial Classification Code 20-39,  have gross
annual sales not exceeding $75 million, employ no  more than
500 persons, and lack in-house expertise in waste minimiza-
tion.

The potential benefits of the pilot project include minimization
of the amount of waste generated by manufacturers and re-
duction of waste treatment and disposal costs for participating
plants. In addition, the project provides valuable experience for
graduate and undergraduate students who participate in the
program and  a cleaner environment without more regulations
and higher costs for manufacturers.

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Methodology of Assessments
The waste minimization assessments require several site visits
to each client served. In general, the WMACs follow the proce-
dures outlined  in the EPA  Waste Minimization Opportunity
Assessment Manual (EPA/625/7-88/003, July 1988). The WMAC
staff locate the  sources of waste in the plant and identify the
current disposal or treatment methods and their associated
costs. They then identify and  analyze  a  variety of ways to
reduce or eliminate the waste. Specific measures to achieve
that goal  are recommended, and the essential supporting tech-
nological  and economic information  is  developed.   Finally,  a
confidential report that details the WMAC's findings and recom-
mendations (including cost savings, implementation  costs, and
payback times)  is prepared for each client.


Plant Background
This plant prewashes predyed denim jeans for wear modifica-
tion  prior to  retail sale.  Over 7  million  pairs  of  jeans  are
processed annually by this plant.


Manufacturing Process
The following steps are involved in processing the jeans:

  •  Predyed jeans are received from other facilities and sorted
    into lots.

  •  Jeans are washed to strip dye and starches from the material.
    An abrasive is used in 10% of the washing loads. Some of the
    jeans go directly to tumblers.

  •  Some of the washed jeans and other jeans not previously
    washed are processed in tumblers where they are physically
    and chemically abraded with pumice and enzymes to give the
    jeans a faded and "worn" look. Other jeans go directly to
    drying after washing. Jeans are rewashed after tumbling.

  •  The garments are dried, inspected, and  mended as needed.

  •  Garments are graded as first, second, or third quality.

  •  Garments are steam  pressed, labels are applied, and the
    prewashed  jeans are  packaged and shipped to distribution
    centers.
An abbreviated process flow diagram for producing prewashed
jeans is shown in Figure 1.


Existing Waste Management Practices
This plant already has implemented the following techniques to
manage and minimize its wastes:

  •  Containers in which the jeans are received are disassembled
    and shipped back to the supplier for reuse.

  •  Pumice of an acceptable size  is reused.


Waste Minimization Opportunities
The type of waste currently generated by the plant, the source
of the waste,  the waste management method,  the quantity of
the waste, and the annual treatment and  disposal cost for each
waste stream identified are given  in Table 1.
      Jeans
Pumice,
enzymes
                                                 Pumice
                                                (for 10% of
                                                  loads)
                                          Finished jeans
                                          packaged and
                                            shipped
Figure 1. Abbreviated process flow diagram for producing prewashed
         jeans.
Table 2 shows the opportunities for waste minimization that the
WMAC team recommended  for the plant. The  minimization
opportunity, the type of waste, the possible waste reduction
and  associated  savings, and the  implementation cost along
with  the  simple  payback time are given in the table. The
quantities of waste currently  generated by the plant and pos-
sible waste reduction depend on the production level of the
plant. All values should  be considered in that context.

It should be noted that, in most cases, the economic savings of
the minimization opportunities result from the  need for less raw
material and from reduced present and future costs associated
with  hazardous waste treatment and disposal.  Other savings
not quantifiable by this study  include a wide variety of possible
future costs related to changing emissions standards, liability,
and employee health. It also  should be noted that the savings
given for each opportunity reflect the savings achievable when
implementing each waste  minimization opportunity indepen-
dently and do not reflect duplication of savings that may result
when the opportunities are implemented in  a  package.

This  research brief summarizes a part of the  work done under
Cooperative Agreement No. CR-814903 by the  University City
Science Center under the sponsorship of the U.S.  Environmen-
tal Protection Agency.  The  EPA Project Officer was  Emma
Lou  George.

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Table 1. Summary of Current Waste Generation
Waste Stream
Generated Source of Waste
Wastewater Washers
Wastewater Tumblers
Evaporated water Dryers and other sources
Pumice and lint Removed from wastewater
using hydrosieve and shaker
screen
Pumice grit Settles out of wastewater in
holding pit
General plant waste Various processes
1 Includes waste treatment, disposal, and handling costs a
Table 2. Summary of Recommended Waste Minimization i
Waste Stream
Minimization Opportunity Reduced
Install an onsite wastewater Wastewater
treatment plant to treat spent from washers
water from the washing and Wastewater
tumbling operations. Reuse from tumblers
treated water. A nonhazardous
sludge will be generated if this
opportunity is implemented.
Reuse rinse waters used in the Wastewater
washing operations during the from washers
Waste Management Method
Filtered; sewered
Filtered; sewered
Evaporates to plant air
Shipped to municipal landfill
Shipped to special landfill
Compacted; shipped to
municipal landfill
nd applicable raw material costs.
Opportunities
Annual Waste Reduction
Quantity (Ib) Percent
513,250,000 95
50,760 95
284,856,000 53
Annual Quantity Annual Waste
Generated (Ib) Management Cost1
533,869,230 $210,170
53,387,090 20,980
39,425,000 13,110
1,137,500 105,440
349,500 37,580
1,650,000 73,760
Net Annual Implementation Simple
Savings Cost Payback (yr)
$350,0001 $1,570,000 4.5
95,480 23,260 0.2
 next washing cycle.

Install a screen over the dump-      Pumice and lint           140,000          40
 ster that is used to collect pumice
 from the hydrosieve and the
 shaker screen in order to recover
 additional pumice stones for reuse.

Install plastic shrouds to reduce      Pumice and lint           140,000          40
 pumice lost in the space between
 the housings and drums in the
 tumblers.
23,690
18.6901
3,300
3,000
                                  0.1
              0.2
Meter the wastewater leaving the    Wastewater
 plant in order to reduce sewer
 charges.  Currently, the plant's
 sewer charges are based on the
 amount of water purchased not on
 the amount of water sewered.
 A significant amount of water is
 absorbed by the jeans in the
 washing process and subsequently
 removed by drying. In addition other
 water losses from spills and steam
 pressing occur.
  7,125
5,140
                                                                                                                           0.7
1  Total annual savings have been reduced by the annual operating cost required for implementation.

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United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
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