&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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United States Center for Environmental Research BULK RATE
Environmental Protection Information POSTAGE & FEES PAID
Agency Cincinnati OH 45268 EPA PERMIT NO. G-35
Official Business
Penalty for Private Use $300
EPA/600/M-91/016
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