&EPA
                          United States
                          Environmental Protection
                          Agency
                                  Risk Reduction
                                  Engineering Laboratory
                                  Cincinnati, OH 45268
                           Research and Development
                                  EPA/600/M-91/016 Jul. 1991
ENVIRONMENTAL
RESEARCH   BRIEF
                       Waste Minimization Assessment for a
                    Manufacturer of Outdoor Illuminated Signs

                              F. William Kirsch 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 hazardous waste but
lack the expertise to do so. Waste Minimization Assessment
Centers (WMACs) were established at selected universities
and procedures were adapted from the EPA Waste Minimiza-
tion Opportunity Assessment Manual (EPA/625/7-88/003, July
1988). The WMAC team at the University of Tennessee in-
spected a plant making large and small outdoor signs with the
use of steel channels and sheeting, plastic sheeting, paint,
adhesives, electrical wiring, and hardware. The team's report,
detailing their findings and recommendations, identified the
greatest opportunities to minimize waste in the painting, clean-
ing, and letter gluing operations. The greatest savings would
result from  the reactivation of an unused electrostatic paint
spray system.

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 the authors.

Introduction
The amount of hazardous waste generated by industrial plants
has become an increasingly costly problem for manufacturers
                     and an additional stress on the environment. One solution to the
                     problem of hazardous 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 hazardous waste but
                     lack the inhouse 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
                     manufacturing plants and also have the knowledge and skills
                     needed to minimize hazardous 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 inhouse expertise in waste minimization.

                     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
"University City Science Center, Philadelphia, PA 19104.
                                                                     '.X/l. Printed on Recycled Paper

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without more regulations and higher costs for manufacturers.

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 locates the sources of hazardous 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 support-
ing technological and economic information is  developed. Fi-
nally, a confidential report that details the WMAC's findings and
recommendations (including cost savings, implementation costs,
and payback times) is prepared for each client.

Plant  Background
A waste minimization assessment was done for  a plant making
various sizes and styles of illuminated outdoor signs. The plant
annually produces approximately 10,400 signs  ranging in size
from 18 x 18 in. to 13 x 13ft.

The materials used by the plant to produce the signs include
steel channels and sheeting, plastic sheeting, paint, adhesives,
electrical wiring, and hardware.

To  reduce  its emission of hazardous waste,  the plant had
already installed a distillation unit for solvent recovery and a
down-draft paint booth system with electrostatic painting capa-
bilities.
Process Operations
    The following processes are involved in producing the
    signs.

        Steel stock is cut to desired measurements for
        components to make sign frames.

        Electrical wiring, sockets, and ballasts are fastened
        to the interior frame surfaces.

        Frames are manually spray primed and painted.

        Plastic  sheeting is cut to desired shape for sign
        faces.

        Some sign faces are vacuum-formed to create
        raised lettering or protrusions on sign faces.

        Sign faces that have been vacuum-formed are
         lettered. The faces are initially sprayed with a
         masking medium. When dry, the masking medium
         is cut from the areas requiring paint and sign faces
         are painted with a hand-held spray gun.

         The remaining sign faces are lettered by fastening
         preformed plastic letters to the faces with
         an adhesive or by silk screen painting the desired
         pattern onto the face.

         Silk screen surfaces are cleaned with Hi-Sol 10 or
         methylethyl ketone (MEK) to remove paint. The
         solvent used depends on the ease of removal of
         the paint.

         Paint spray guns are cleaned using xylene or
         KH5000*, depending upon the type of paint used.

         Paint/solvent mixtures from the screen cleaning
         and spray gun cleaning are distilled to recover
         usable solvents. Paint sludge and unreclaimed
         xylene, Hi-Sol 10, and KH5000 are shipped off-
         site as hazardous waste.

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 manage-
ment (treatment and disposal) costs are given in Table 1.

The WMAC team investigated various options for minimizing the
plant's generation of hazardous waste. Waste minimization
opportunities related to the sign frame paint booths, the silk
screen cleaning operation, and the letter gluing operation are
described in Tables 2,3, and 4, respectively. For each opportu-
nity, the type of waste, the possible waste reduction and asso-
ciated savings, and the implementation cost along with the
payback time are given in the tables. The quantities of hazard-
ous waste currently generated by the plant and possible waste
reduction depend on the production level of the plant. All values
stated 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.

Additional Recommendations
In addition to the recommended waste minimization opportuni-
ties, the WMAC team indicated that the plant personnel should

  Mention of trade names or commercial products does not consti-
  tute endorsement or recommendation for use.

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 Table 1. Summary of Current Watte Generation


 Waste Generated                Source of Waste
                                            Annual Quantity Generated      Annual Waste
                                                     (gal)              Management Cost
 Paint and primer residue
 Evaporation of paint thinner
 (KH5000)
 Evaporation of methylene
 chloride
 Evaporation of Hi-Sol 10
 and Hi-Sol 10 not recovered
 from distillation process

 Evaporation of MEK

 Evaporation of xylene
 and xylene not recovered
 from distillation process

 Evaporation of KH5000
 and KH5000 not recovered
 from distillation process

 Spent, contaminated paint
 sludge
 Paint booth for large sign frames. Dried paint/primer         385
 dust is removed from the walls of the booth. Paint
 pverspray is also collected by a down-draft air system
 into a flowing water stream; the paint/primer residue
 is recovered from the water stream with the use of a
 centrifuge.

 Paint booth for small sign frames. Dried paint/primer         275
 dust is removed from the tables, walls, ceiling, and
 floor.

 Paint booth for spray painting of sign faces. Dried           550
 paint/primer dust is removed from the walls and floors
 of the booth.

 Paint booth for large sign frames.                          43
Paint booth for small sign frames.                          30

Letter gluing operation. A substantial amount of             330
methylene chloride evaporates into the plant air as
methylene chloride is used to facilitate bonding the
letters to the sign faces.

Cleaning silk screens.                                 4,125
Cleaning silk screens.                                   330

Cleaning paint spray guns.                               154



Cleaning pain spray guns                                185



Distillation process for recovery of cleaning solvents.         165
                                                                                                           $14,080
                                                                                                             4,440
                                                                                                             9,080
     O1

     O2




 4.7103



     O4

 9.7403



 4.7103



14.450s
 1 Currently there are no waste management costs associated with the evaporation of the paint thinner.
 2 Currently there are no waste management costs associated with the evaporation of the methylene chloride.
 3 Cost of off-site removal of unreclaimable solvent and cost of operating distillation process.
 4 Currently there are no waste management costs associated with the evaporation of methylethyl ketone.
 5 Cost of off-site removal of paint sludge and cost of operating distillation process.
make  an ongoing effort to identify  superior  alternatives to
presently used solvents to minimize hazardous wastes.

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 Brian A.
Wesfall.
                                The EPA contact, Emma L. George, can be reached at:
                                    Pollution Prevention Research Branch
                                    Risk Reduction Engineering Laboratory
                                    U.S. Environmental Protection Agency
                                    Cincinnati, OH 45268

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 Table 2.  Opt/on* for Minimizing Waste Generated In the Paint Booths lor Large and Small Sign Frames
Waste Generated
Paint/primer residue
Paint thinner
(KH5000)

Annual Waste Reduction
Minimization Opportunity
Reactivate the currently
unused electrostatic
paint spray system
Use paint atomization
spray equipment having
adjustable cross-sectional
Quantity
495 gal2
55 gal3
165 gal2
18 gal3
Percent
75
75
25
25
Net Annual
Savings '
$25,410
180
8,470
60
Implementation Payback
Cost Years
$4,400 0.2

6,000 0.7
                       areas for maximum paint
                       application efficiency for
                       the particular frame being
                       sprayed.
Retrain paint 66 gal2
application personnel to
use techniques employing 7 gaP
minimal distance from spray
gun to target area and minimum
overspray at piece edges.
10
10
3,390
20
3,000 0.9
 1 Includes savings on disposal costs and raw materials.
 2 Primer
 3 Thinner
 Table 3. Options for Minimizing Waste Generated by the Silk Screen Cleaning Process
Annual Waste Reduction
Waste Generated
Hi-Sol 102

MEK

Spent, contaminated
paint sludge



Minimization Opportunity
Minimize the amount of
residual paint left on the
screens before cleaning with
solvents. Use smal sharp-
edged scraping tools and
hand-held compressed air
spray nozzles to remove
residual paint before solvent
cleaning.
Quantity
2,063 gal

165 gal

55 gal




Percent
50

50

33




Gross Annual
Savings 1
$8,540

580

4,820




Implementation Costs
Operating Capital Payback
Cost Cost Years
$9,3003 $700 0.15








Hi-Sol 10 evaporation Construct an enclosure to
                    serve as a screen spray
MEK                cleaning booth. Evaporative
                    loss of solvents will be
                    minimized as a result of using
                    an automatic cleaning system
                    in an essentially air-tight
                    space.
3,300 gal

 264 gal
80

80
9,900

  920
$22,880
2.1
1  Includes savings on raw materials.
2  Evaporation of Hi-Sol 10 and Hi-Sol 10 not recovered from distillation process.
3  Additional costs include increased labor costs associated with more thorough mechanical removal and off-site removal costs of
  dried paint waste.

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Table 4.  Options for Minimizing the Evaporative Lo»» ofMethylene Chloride used for Letter Gluing

                                                    Annual Waste Reduction
Waste Generated    Minimization Opportunity
                                Quantity
Methylene chloride
Use a template to maintain
position of letters during over-
night curing in place of me thy I-
ene chloride.

Use a removable adhesive tape
to hold the letters in place while
the glue is cured overnight.

Fix the letters to the signs
using mechanical means such
as fasteners.
Eliminate the use of adhesives.
330 gal
                                                     330 gal
                                                     330 gal
               Percent
           Net Annual
            Savings'
                Implementation
                     Cost
Payback
 Years
100
                 100
                 100
$1,980
                               1,980
              5,260 2
                                 $200
                                  100
                                                 1,500
                                                                                                                        0.1
                                                  0.05
                                     0.3
1  Includes savings on raw materials.
2  Includes savings associated with the elimination of the cost of adhesives.
                                                                      •&LI.S. GOVERNMENT PRINTING OFFICE: 1991 - S4S-02H/40033

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EPA/600/M-91/016
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