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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 That document has been superseded by the Facility Pollution Prevention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 the

University of Tennessee performed an assessment at a plant

that manufactures turbochargers, fan drives, and vibration dampers for truck engines. Metal castings are machined and cleaned;

degreased, coated and/or painted, if required; and assembled,

inspected, packaged, and shipped. The team’s report, detailing

findings and recommendations, indicated that the plant could

achieve significant cost savings by replacing its solvent-based

painting system with an electrostatic powder coating system,

thereby reducing paint overspray.

This Research Brief was developed by the principal investigators and EPA’s Risk Reduction Engineering 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

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 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 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 $75 million, employ no more than

500 persons, and lack in-house expertise in waste minimization.

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.

Methodology of Assessments

The waste minimization assessments require several site visits

to each client served. In general, the WMACs follow the proceWaste Minimization Assessment for a Manufacturer

of Parts for Truck Engines

United States

Environmental Protection

Agency

Risk Reduction

Engineering Laboratory

Cincinnati, OH 45268

ENVIRONMENTAL

RESEARCH BRIEF

Research and Development EPA/600/S-94/019 September 1994

Richard J. Jendrucko*, Kelly Binkley*, Todd Thomas*, Stephanie Wilson*,

Eric W. Daley**, and Gwen P. Looby**

* University of Tennessee, Department of Engineering Science and Mechanics.

* University City Science Center, Philadelphia, PA.

E AP
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dures 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

The plant manufactures turbochargers, fan drives, and vibration dampers for truck engines. It operates approximately 6,000

hr/yr to produce more than 600,000 units annually.

Manufacturing Process

The major raw materials used by the plant are iron, aluminum,

magnesium, and steel castings. Manufactured parts purchased

by the plant include bearings, finger sleeves, bands, studs, and

rubber strips.

For the production of turbochargers, steel castings undergo a

vapor degreasing operation and friction welding. In parallel

operations, the steel, aluminum, and iron castings are turned,

drilled, tapped, and sent through an alkaline cleaner. The

finished parts are assembled into complete turbocharger units,

packaged, and shipped.

In the fan drive production line, aluminum, magnesium, iron,

and steel castings are turned, drilled, and tapped, resulting in

rotors, shafts, and bearing housings. Rotors are sandblasted,

vapor degreased, spray-coated with a wear-resistant formulation, and heated in a curing oven. The shafts and bearing

housings, after an alkaline cleaning, are assembled with the

finished rotors. The finished product is packaged and shipped.

To produce dampers, iron castings are first turned, drilled, and

tapped. The parts are cleaned and conveyed through a secondary phosphate etchant. After heating, the parts are primed,

coated with rubber, heated again, cleaned, painted, and cleaned

again. Finished parts are assembled, packaged, and shipped.

An abbreviated process flow diagram for this plant is shown in

Figure 1.

Existing Waste Management Practices

This plant already has implemented the following techniques to

manage and minimize its wastes:

• Onsite solvent recovery units are used to distill spent

degreasing solvent for reuse.

• Several waste streams, including an anti-rust treatment and

cleaning chemicals, have been eliminated from the production process.

• A heat pump evaporator has been purchased for drying of

wastewater sludge.

• Waste cardboard is baled and sold to a recycler.

• Waste metals are compacted into blocks and sold as scrap.

Waste Minimization 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 waste minimization that the

WMAC team recommended for the plant. The minimization

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 financial savings of the minimization

opportunities result from the need for less raw material and

from reduced present and future costs associated with waste

management. Other savings not quantifiable by this study include a wide variety of possible future costs related to changing emissions standards, liability, and employee health. It also

should be noted that the savings given for each opportunity

reflect the savings achievable when implementing each waste

minimization opportunity independently and do not reflect duplication of savings that would result when the opportunities

are implemented in a package.

Additional Recommendations

In addition to the opportunities recommended and analyzed by

the WMAC team, two additional 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 waste

reduction may, however, increase in attractiveness with changing conditions in the plant, they were brought to the plant’s

attention for future consideration.

• Reduce the frequency of leaks and spills of hydraulic oil.

• Dispose of spent coolant through a method other than the

onsite wastewater treatment plant.

This research brief summarizes a part of the work done under

Cooperative Agreement No. CR-914903 by the University City

Science Center under the sponsorship of the U.S. Environmental Protection Agency. The EPA Project Officer was Emma

Lou George.
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Metal castings Metal castings Metal castings

Vapor degreasing Machining Machining

Welding

Cleaning Sand blasting Cleaning Etching

Cleaning

Cleaning

Machining

Assembly Assembly

Assembly

Vapor degreasing

Coating

Curing

Coating Priming

Trimming Painting

Turbochargers shipped to customers Fan drives shipped to customers Dampers shipped to customers

Figure 1. Abbreviated process flow diagram for truck engine parts manufacture.
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Table 1. Summary of Current Waste Generation

Annual Quantity Annual Waste

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

Rejected metal castings Inspection of raw materials Returned to supplier 102,800 $0

Metal chips Machining operations Compacted into blocks; sold to recycler 398,772 -15,450

Wastewater (contains coolant, Machining operations, Treated in onsite wastewater 3,046,080 118,820

 alkaline cleaner, iron phos- cleaning operations, treatment plant; sewered

 phate cleaner) etching

Evaporated perchloroethylene Vapor degreasing Evaporates to plant air 12,580 4,780

Perchloroethylene still bottoms Onsite recovery unit Shipped offsite as hazardous waste 740 1,380

Spent hydraulic oil Machining operations Shipped offsite as hazardous waste 23,080 1,660

Metal grindings and spent Grinding of parts Shipped to landfill 12,000 1,610

 grinding wheels

Steam-washer sludge Cleaning of production equipment Shipped offsite as hazardous waste 6,000 16,450

Spent powder abrasive Sandblasting Shipped to landfill 8,000 810

Evaporated “Genesolv” Vapor degreasing Evaporates to plant air 13,400 22,520

“Genesolv” still bottoms Onsite recovery Shipped offsite as hazardous waste 590 2,170

Unusable TeflonTM dust Overspray from coating operation Shipped to landfill 880 2,180

Evaporated mineral spirits Parts cleaning Evaporates to plant air 1,470 560

Spent mineral spirits Parts cleaning Shipped offsite as hazardous waste 4,400 5,130

Residual primer mixture Painting Shipped offsite as hazardous waste 6,600 16,450

Residual adhesive Overspray from adhesive application Shipped offsite as hazardous waste 550 1,660

Evaporated toluene Primer application Evaporates to plant air 13,725 0

Evaporated methyl ethyl ketone Adhesive application Evaporates to plant air 1,100 0

Paint overspray Painting Shipped offsite as hazardous waste 1,000 7,530

Paint containers Painting Sold to reclaimer 1,440 1,310

Paint filters Paint spray booths Shipped offsite as hazardous waste 30 2,980

Evaporated thinner Painting Evaporates to plant air 7,130 0

Cardboard Disassembly of returned parts Baled; sold to recycler 24,000 1,390

Filters Wastewater treatment plant Shipped to landfill 180 6,080

Waste oil Wastewater treatment plant Shipped offsite as hazardous waste 27,950 2,020

1Includes waste treatment, disposal, and handling costs and applicable raw material costs.
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Table 2. Summary of Recommended Waste Minimization Opportunities

Annual Waste Reduction

Net Annual Implementation Simple

Minimization Opportunity Waste Reduced Quantity (lb) Percent Savings Cost Payback (yr)

Reuse treated water from the onsite Wastewater 431,600 14 $2,340 $10,900 4.7

 wastewater treatment facility for

 mopping and equipment washdown.

 Discharged water should be monitored

 for zinc and if the permitted threshold for

 that constituent is exceeded, the water

 should be treated accordingly.

Install an electrostatic powder paint Residual primer mixture 6,600 100 59,030 46,260 0.8

 coating system to replace the solvent- Paint overspray 1,000 100

 based spray paint booths used Paint containers 1,440 100

 currently. Paint filters 30 100

Install a small distillation unit for the Spent mineral spirits 4,400 100 4,430 13,320 3.0

 onsite recovery and reuse of spent

 mineral spirits. A small quantity of

 still bottoms will be generated and

 shipped offsite if this opportunity is

 implemented.

Fabricate and utilize conveniently re- Evaporated Genesolv 6,664 50 13,650 440 0.1

 movable, lightweight corrosion- Evaporated perchloroethylene 6,290 50

 resistant plastic covers for the

 vapor degreasers to reduce evapor-

 ative losses.
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United States

Environmental Protection Agency

Center for Environmental Research Information

Cincinnati, OH 45268

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35

Official Business

Penalty for Private Use

$300

EPA/600/S-94/019