United States
                         Environmental Protection
                                      Risk Reduction
                                      Engineering Laboratory
                                      Cincinnati OH 45268
                         Research and Development
                                      EPA/600/S-92/017 June 1992
                         Waste Minimization Assessment for a
                           Manufacturer of Military Furniture

                               F. William Kirsch and Gwen P. Looby*
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. Waste Minimization Assessment Cen-
ters (WMACs) were established at selected universities, and
procedures were adapted from the EPA Waste Minimization
Opportunity Assessment Manual (EPA/625/7-88/003, July 1988).
The WMAC team at the University of Tennessee performed an
assessment at a plant manufacturing military  furniture—ap-
proximately 12,000 units/yr. Wood and formica  are laminated
together via glue curing and then undergo woodworking opera-
tions including cutting, drilling, and routing. Finished boards are
either packaged and shipped or transported to assembly. Metal
stock is cleaned with solvent and then undergoes  various
metalworking operations. Metal pieces are partially assembled,
painted, then either packaged and shipped or  transferred to
assembly before being packaged and shipped. The team's
report, detailing findings and recommendations, indicated that
the majority of waste was generated during the painting opera-
tions and that the greatest savings could  be obtained by
installing an electrostatic powder coating system to completely
eliminate paint solvent evaporation, paint solids waste, and
paint-laden air filters.

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 document of the
same title available from the authors.
                         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 prob-
                         lem of waste 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 formation 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 $50 million, employ no more than
                         500 persons, and lack in-house expertise in  waste minimiza-

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

                                                  GyD Printed on Recycled Paper
• University City Science Center, Philadelphia, PA 19104

 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 Afanoa/(EPA/625/7-88/003, July 1988). The WMAC
 staff locates the sources of waste in the plant and identifies 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. Figure 1 shows a
 simplified process flow diagram of the operation of the plant.

 Plant Background
 The plant manufactures military-specification furniture for use
 in military barracks. Ninety employees operate the plant 2,080
 hr/yrto produce approximately 12,000 units of furniture annu-
Manufacturing Process         •
The plant produces wooden, wood with steel frame, and steel
furniture. Raw materials include heavy-density particle board,
steel frame, rolls and strips of sheet steel, formica, and as-
sorted hardware.                     !

Unit  operations  performed  in  processing  wood  include the
  • Raw wood and formica are glued together to form a
    laminate. Several laminations are then positioned in a
    press for glue curing. Next, the boards undergo vari-
    ous woodworking operations including cutting, drilling,
    and routing. Boards are either transferred to assembly
    or directly packaged and shipped.  ;

Metal processing involves the following unit operations:

  • Metal stock is cleaned by immersion in a toluene dip
    tank.  Waste from this process  includes evaporated ,
    toluene  and  sludge  containing toluene, grease,  and
    dirt, which is pumped from the bottom of the tank.
    After  cleaning, the metal undergoes various metal-
    working  operations including cutting, punching, fold-
Metal Stock
Dipped in



and Sludge

Paint Waste

                                                       Package and Ship
Flgun 1.    Simplified process flow diagram.

    ing, and welding. Pieces are partially assembled, then
    transferred to one of two spray-paint lines or a dip-
    paint line.
  • In the spray-paint line,  parts undergo a five-stage
    cleaning  in  preparation for spray-painting. The first
    stage is  an alkaline-wash  tank held at 110°F. That
    wash stage is followed by a rinse tank. Next, parts are
    sprayed with an iron phosphate solution. The fourth
    stage is  a rinse tank, fn the final stage, parts are
    sprayed  with  a rust preventive. After cleaning, the
    parts are conveyed first  through a dry-off oven and
    then through the spray-painting process.
  • In spray-painting, paint is  applied to the parts  with
    hand-held spray guns. The paint booths are equipped
    with continuously recirculating water curtains to en-
    trap paint overspray. Entrapped paint solids and waste-
    water are dumped to a holding tank periodically. Air
    filters which  are used  in two of the  four booths to
    collect overspray  are also disposed  of periodically.
    After painting, the parts are conveyed through a dry-
    off oven and undergo further assembly.
  • Small metal parts are dip-painted,  allowed to air dry,
    and then transferred  to the assembly area.
  • Assembly and packaging.

Existing Waste Management Practices
  • A steam-cleaning operation to eliminate the five-stage
    cleaning  of some metal parts is being investigated.
  • The use of dip-painting has been minimized.
Waste Minimization Opportunities
The type of waste currently generated by the plant, the source
of the waste, the quantity of  the waste, and the annual  man-
agement costs are given  in  Table 1.

Table 2 shows the opportunities for waste minimization that the
WMAC team  recommended for the plant.  The type of waste,
the minimization opportunity, the possible waste reduction and
associated savings, and the implementation cost along with the
payback time  are given in the  table. The  quantities of waste
                                     currently generated by the plant and possible 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 waste treatment and disposal. Other savings not quantifi-
                                     able  by this study include  a wide  variety of  possible future
                                     costs .related to changing  emissions standards, liability, and
                                     employee health. It should also be noted that the savings given
                                     for each opportunity reflect the savings achievable when imple-
                                     menting each  waste minimization  opportunity independently
                                     and do not reflect duplication of savings that would result when
                                     the opportunities are implemented in a package.

                                     Additional Recommendations
                                     In addition to the opportunities recommended and analyzed by
                                     the WMAC team, two additional measures were considered.
                                     These  measures were not analyzed completely because  of
                                     insufficient data or minimal savings as indicated below. They
                                     were brought to the plant's attention for future reference, how-
                                     ever, since these approaches to waste reduction may increase
                                     in attractiveness with changing plant conditions.

                                       • If the spray paint process is not replaced as recom-
                                         mended in the WMOs, there are two  other possible
                                         improvements to be considered. A state-of-the-art dip
                                         paint line with safeguards to minimize paint dripping
                                        on floors could be installed to replace the  paint lines.
                                         Another alternative is to switch  from solvent-based to
                                        water-based paints.
                                       • Use air-tight spray gun cleaning tanks to reduce evapo-
                                         rative losses of toluene.

                                     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
Table 1. Summary of Current Waste Generation
                                                                                           Annual        Annual
                                                                                          Quantity     Waste Manage-
Waste Generated
Toluene sludge
Evaporated toluene
Evaporated paint solvent
Paint-laden air filters
Source of Waste
Toluene-dip tank for cleaning of metal stock. The sludge, which contains
toluene, grease, and dirt, is hauled offsite as a hazardous waste.
Toluene-dip tank for cleaning of metal stock.
Spray-paint booths.
Spray-paint booths.
715 gal
172 gal
915 gal
832 filters
3,390 gal paint
ment Cost
Toluene sludge

Evaporated toluene

Paint solids
Cleaning of paint guns. The sludge, which contains toluene and paint,          55 gal          630
is hauled offsite as a hazardous waste.

Cleaning of paint guns.                                                44 gal            0'

Holding tanks which receive wastewater from the five-stage cleaner           7,515 gal        3,750
and the painting operation.
' According to plant personnel, there are no waste management costs associated with evaporation of solvents.
                                                                                  •U.S. Government Printing Office: 1992— 648-080/60013

Summary of Recommended Waste Minimization Opportunities
paint solvent
Paint laden air
Paint solids
Toluene sludge
Minimization Opportunity
Install an electrostatic powder coating
system to replace the paint-spray and dip-
paint lines. The proposed system will
provide more even coating of parts and
easy collection and reuse of overspray
Protect the clean metal stock from
environmental dirt to eliminate the need
for subsequent cleaning In the toluene-dip
Annual Waste
915 gal
832 filters
3,390 gal paint2
44 gal
7,515 gal
715 gal
172 gal
Net Imple-
Annual ! mentation
Savings Cost
Evaporated       Repair the lid of the toluene-dip tank to
  toluene         reduce evaporative losses. Institute a
                 program to keep lid closed whenever
                                                   86 gal
100     0.5
Paint solids
Re-install the existing electrostatic 2,210 gal 29 39.SSO'-3
spray paint system in building 4 and
Install an electrostatic spray paint
system in building 3. The electrostatic
spray paint systems will be considerably
more efficient than the current spray-
paint systems.
66,900 1.7
* Paint associated with the spent air filters.
3 Total savings have been reduced by the operating cost of the proposed system.
United States
Environmental Protection
                                     Center for Environmental
                                     Research Information
                                     Cincinnati, OH 45268
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