&EPA
United States
Environmental Protection
Agency
Research and Development
National Risk Management
Research Laboratory
Cincinnati, OH 45268
EPA/600/S-95/024 September 1995
ENVIRONMENTAL
RESEARCH BRIEF
Pollution Prevention Assessment for a Manufacturer of
Wooden Cabinets
Harry W. Edwards*, Michael F. Kostrzewa*,
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ment has been superseded by the Facility Pollution Prevention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
Colorado State University performed an assessment at a plant
that manufactures wooden kitchen and bathroom cabinets.
Components purchased from vendors are prepared for produc-
tion through cutting, sanding, and routing operations. Stain,
sealer, and top-coat are applied in separate spray booths. After
the final coating, the components are dried and assembled.
The assessment team's report, detailing findings and recom-
mendations, indicated that paint sludge from the spray booth
water curtains is generated in a large amount and that signifi-
cant cost savings could be achieved by dewatering the sludge
before it is shipped offsite for disposal and reusing the water.
This Research Brief was developed by the principal investiga-
tors and EPA's National Risk Management Research Labora-
tory, Cincinnati, 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.
* Colorado State University, Department of Mechanical Engineering
** 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
National Risk Management Research Laboratory, the Science
Center has established three WMACs. This assessment was
done by engineering faculty and students at Colorado State
University's (Fort Collins) 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 pollution prevention opportunity 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 pollution
prevention.
The potential benefits of the pilot project include minimization
of the amount of waste generated by manufacturers, and
reduction of waste treatment and disposal costs for participat-
ing plants. In addition, the project provides valuable experi-
ence for graduate and undergraduate students who participate
in the program, and a cleaner environment without more regu-
lations and higher costs for manufacturers.
Printed on Recycled Paper
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Methodology of Assessments
The pollution prevention opportunity assessments require sev-
eral site visits to each client served. In general, the WMACs
follow the procedures 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 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
This plant manufactures wooden kitchen and bathroom cabi-
nets. It operates 2,200 hr/yr to produce about 150,000 cabinets
annually.
Manufacturing Process
Most of the cabinet doors and components used in producing
the cabinets are received pre-cut from outside vendors. Other
components are sent to a preparation area where they are cut,
sanded, and edged. Components are then stored until needed
on the painting line.
Employees use a printout of the day's scheduled production to
send the correct components to the painting area in the proper
order and quantity. First, the parts are sent by conveyor to a
staining booth that uses air-assisted airless spray guns that
rotate and coat the components on one side as they are
passed through the booth. After exiting the booth the parts are
flipped over and sent through a second staining booth where
they are stained on the other side. Overspray is captured by a
water curtain, and solvents are allowed to evaporate.
Next the components travel to another spray booth for sealer
application. The sealer booth uses air-assisted airless guns to
spray one side of the components. Again, overspray is cap-
tured by a water curtain. The parts then travel to a final
painting booth for top-coat application. Overspray is collected
in the same manner as in the other booths.
After the final coating, the components are dried in a large kiln
and then sent to the assembly line. The parts are glued and
stapled into finished cabinets, and drawers are assembled in a
similar manner. The face boards are added as the cabinets
move down the line. The cabinet doors are pre-hinged and
then fastened to the cabinets. Assembled cabinets are in-
spected and shipped.
An abbreviated process flow diagram is shown in Figure 1.
Existing Waste Management Practices
This plant already has implemented the following techniques to
manage and minimize its wastes.
• Soap is used instead of lacquer thinner for cleaning the steel
conveyor bands on the painting lines. Prior to the change to
soap cleaning, approximately one drum of lacquer thinner
was used each day for cleaning the bands.
• Used wooden pallets are recycled offsite when possible.
Pollution Prevention 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 waste management cost for each
waste stream identified are given in Table 1.
Table 2 shows the opportunities for pollution prevention that
the WMAC team recommended for the plant. The 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 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 reductions in raw
material and 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 chang-
ing emissions standards, liability, and employee health. It also
should be noted that the savings given for each opportunity
reflect that pollution prevention opportunity alone and do not
reflect duplication of savings that would result when the oppor-
tunities are implemented in a package.
Additional Recommendations
In addition to the opportunities recommended and analyzed by
the WMAC team, two other measures were considered. These
measures were not analyzed completely because of insuffi-
cient data, implementation difficulty, or a projected lengthy
payback. Since one or more of these approaches to pollution
prevention may, however, increase in attractiveness with chang-
ing conditions in the plant, they were brought to the plant's
attention for future consideration.
• Replace the water curtains in the paint booths with a dry filter
bed for collection of overspray.
• Install air-assisted airless fine finish paint guns and paint line
heaters to reduce the amount of paint overspray generated.
This research brief summarizes a part of the work done under
Cooperative Agreement No. CR-819557 by the University City
Science Center under the sponsorship of the U. S. Environ-
mental Protection Agency. The EPA Project Officer was Emma
Lou George.
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Pre-Cut Cabinet Doors
and Other Components
Preparation
- Cutting
•»
- Sanding
- Routing
1
Stain
Application
'
1
Sealer
Application
\
t
1 Top Coat
Application
\
r
Drying
1
r
Assembly
\
Inspection
^—
Completed Cabinets
to Customers
Figure 1. Abbreviated process flow diagram for wooden cabinet manufacturers.
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. Summary of Current Waste Generation
Waste Generated
Paint sludge
Evaporated lacquer thinner
Evaporated paint solvents
Wasta lacquer thinner
Miscellaneous soKd waste
Source of Waste
Water curtain in sealer and top-coat
spray lines
Stain, sealer, and topcoat lines
Spray booths
Cleaning of equipment
Various operations
Waste Management Memoa
Shipped off site for disposal as
hazardous waste
Evaporates to plant air
Evaporate to plant air
Shipped offsite for disposal as
hazardous waste
Shipped offsite to municipal landfill
ueneraieo cu/y/
130,000
19,030
236,000
38,900
364,000
$101,000
10.0101
0
33,200r
23,600
11ncludes lost raw material value.
Summary of Recommended Pollution Prevention Opportunities
Annual Waste Reduction
Pollution Prevention Opportunity
Waste Reduced Quantity (Ib/yr)
Percent
Net Annual Implementation Simple
Savings Cost Payback (yr)
Install a purification system to reduce the
water content of the paint sludge gener-
ated through treatment of the wastewater
from the water curtains in the sealer and
topcoat spray booths. Implementation
of this opportunity will lead to a reduced
vokme of hazardous waste shipped
otfsite,
Capture the lacquer thinner used for line
cleaning In the paint spray booths and
reuse H. Current practice is to use the
thinner once and spray it into the water
curtain from which it evaporates.
Segregate waste cardboard from other
solid waste, bale it, and sell it to a card-
board recyeter. The resulting reduction
in volume of solid waste will lead to
lower landfill costs. No waste reduction
will result from this opportunity.
Paint sludge
47,000
36
$45,070
$9,600
Evaporated lacquer
thinner
Miscellaneous
solid waste
9,520
50
3,880
5,670
500
4,600
0.1
0.8
United States
Environmental Protection Agency
National Risk Management Research Laboratory (G-72)
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
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POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPAJBOO/S-95/024
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