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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 manufacturers Waste Minimization Assessment Centers (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). That document has been superseded by the Facility Pollution Prevention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. Surface-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 generated in large quantities in the testing and burn-in area, and that

significant cost savings could be achieved through the installation of a closed-loop cooling system.

This Research Brief was developed by the principal investigators and EPA’s National Risk Management Research Laboratory, 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.

Introduction

The amount of 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 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 participating plants. In addition, the project provides valuable experience for graduate and undergraduate students who participate

in the program, and a cleaner environment without more regulations and higher costs for manufacturers.

Pollution Prevention Assessment for a Manufacturer

of Power Supplies

ENVIRONMENTAL

RESEARCH BRIEF

Harry W. Edwards*, Michael F. Kostrzewa*,

and Gwen P. Looby**

 *Colorado State University, Department of Mechanical Engineering.

 **University City Science Center, Philadelphia, PA.

United States

Environmental Protection

Agency

National Risk Management

Research Laboratory

Cincinnati, OH 45268

Research and Development EPA/600/S-95/025 September 1995
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Methodology of Assessments

The pollution prevention opportunity assessments require several 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 supporting technological and economic information is developed. Finally, 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 another 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 prefabricated 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 manufacture 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 implemented.

• 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 emissions 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 changing 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 pollution 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. Environmental Protection Agency. ßThe EPA Project Officer was Emma

Lou George.
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Printed Circuit Boards

Electronic Components

Automated

Assembly

Wave

Solder

Washer

Hand

Assembly

Hand

Soldering

Testing

Burn-in

Shipping

Waste Flux Shipped

Offsite as

Wastewater

Sewered

Cooling Water

Sewered

Electronic Components

Hazardous Waste

Power Supplies

Figure 1. Abbreviated process flow diagram for power supply manufacture.

Table 1. Summary of Current Waste Generation

Annual Quantity Annual Waste

Waste Generated Source of Waste Waste Management Method Generated (lb/yr) Management Cost1

Waste flux Periodic draining from wave soldering Shipped offsite as hazardous waste; incinerated 2,690 $2,370

Wastewater Printed circuit board washer Discharged to sewer as industrial wastewater 1,999,200 670

Cooling water Testing Discharged to sewer as industrial wastewater 15,523,290 5,190

Cooling water Burn-in Discharged to sewer as industrial wastewater 12,571,640 4,210

1 Includes waste treatment, disposal, and handling costs and applicable lost raw material value.
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BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35

United States

Environmental Protection Agency

National Risk Management Research Laboratory (G-72)

Cincinnati, OH 45268

Official Business

Penalty for Private Use

$300

EPA/600/S-95/025

Table 2. Summary of Recommended Pollution Prevention Opportunity

Annual Waste Reduction

Net Annual Implementation Simple

Pollution Prevention Opportunity Waste Reduced Quantity (lb/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.