&EPA
United States
Environmental Protection
Agency
National Risk Management
Research Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-95/025 September 1995
ENVIRONMENTAL
RESEARCH BRIEF
Pollution Prevention Assessment for a Manufacturer
of Power Supplies
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ment has been superseded by the Facility Pollution Prevention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 power supplies from printed circuit boards
and electronic components. Through-hole components are
attached to the boards using a wave soldering machine. Sur-
face-mounted components are mounted onto the boards which
are then combined with cases, frames, and other prefabricated
parts to form power supplies. The product is then tested and
shipped. The assessment team's report, detailing findings and
recommendations, indicated that waste cooling water is gener-
ated in large quantities in the testing and burn-in area, and that
significant cost savings could be achieved through the installa-
tion of a closed-loop cooling system.
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
manufacturing 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.
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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 Manua/(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 power supplies from printed circuit
boards and electronic components. Approximately 50,000 units
are produced annually during 2250 hr/yr of production time.
Manufacturing Process
The raw materials used by the plant—printed circuit boards
and electronic components—are brought to the automated
assembly area. Through-hole components are placed onto the
boards manually, and the boards are passed through a wave
soldering machine to secure the parts in place.
An ethanol-based flux is used by the wave solder machine to
prepare the circuit board surface for soldering. Flux residue
that remains on the boards after soldering is removed in a
semi-automated board washer.
Surface-mounted components are added to the boards in an-
other area of the plant. A flux that leaves no residue and
solder paste are applied to the boards before the parts are put
into place; the parts are then passed through an oven to
secure the components to the board. Washing of the boards is
not required after this operation.
The boards are combined with cases, frames, and other pre-
fabricated parts and assembled into power supplies. Each unit
is then load-tested in a test-area for about two hours. A longer
burn-in test is also performed on each unit. After testing, the
power supplies are packaged and stored to await shipment to
customers.
An abbreviated process flow diagram for power supply manu-
facture is shown in Figure 1.
Existing Waste Management Practices
This plant already has implemented the following techniques to
manage and minimize its wastes.
• A CFC reduction plan/policy has been implemented. All
possible substitutions for CFCs in all plant operations are
being explored; many substitutions already have been imple-
mented.
• A flux that leaves no residue is used for surface-mounted
parts. As a result the boards do not require cleaning after
hand-soldering.
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 opportunity 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 the economic savings of the opportunity
result from the need for less raw material and from reduced
present and future costs associated with waste treatment and
disposal. Other savings not quantifiable by this study include a
wide variety of possible future costs related to changing emis-
sions standards, liability, and employee health.
Additional Recommendations
In addition to the opportunity recommended and analyzed by
the WMAC team, several other measures were considered.
These measures were not analyzed completely because of
insufficient 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.
• Investigate the use of a no-clean wave solder machine in
order to eliminate the need for cleaning following wave
soldering. This technology is currently in the development
stage.
• Install flow reducers on water lines in the test area to restrict
the maximum flow rate available. This opportunity would not
be viable should the plant implement the WMAC team's
recommended waste minimization opportunity.
• Pipe the waste cooling water from the test area to the board
washer in order to provide heated waste water as make-up
to the washer. This opportunity would not be viable should
the plant implement the WMAC team's recommended pollu-
tion prevention opportunity.
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. Environmen-
tal Protection Agency. UThe EPA Project Officer was Emma
Lou George.
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Printed Circuit Boards
Electronic Components
Electronic Components-
waste Flux Shipped
Offsite as
Hazardous Waste ^
Wastewater
Sewered
Power Supplies
Figure 1. Abbreviated process flow diagram for power supply manufacture.
Table 1. Summary of Current Waste Generation
Waste Generated
Source of Waste
Waste Management Method
Annual Quantity Annual Waste
Generated (Ib/yr) Management Cost^
Waste flux
Wastewater
Cooling water
Cooling water
Periodic draining from wave soldering
Printed circuit board washer
Testing
Burn-in
Shipped offsite as hazardous waste; incinerated
Discharged to sewer as industrial Wastewater
Discharged to sewer as industrial Wastewater
Discharged to sewer as industrial Wastewater
2,690
1,999,200
15,523,290
12,571,640
$2,370
670
5,190
4,210
Includes waste treatment, disposal, and handling costs and applicable lost raw material value.
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Table 2. Summary of Recommended Pollution Prevention Opportunity
Annual Waste Reduction
Net Annual Implementation Simple
Pollution Prevention Opportunity Waste Reduced Quantity (Ib/yr) Percent Savings Cost Payback (yr)
Install a closed-loop cooling system Cooling water from testing 15,523,290 100 $9,550 $25,000 2.6
for water used in the testing and Cooling water from burn-in 12,571,640 100
burn-in areas in order to reduce
water usage.
United States
Environmental Protection Agency
National Risk Management Research Laboratory (G-72)
Cincinnati, OH 45268
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