&EPA
United States
Environmental Protection
Agency
National Risk Management
Research Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-95/016 August 1995
ENVIRONMENTAL
RESEARCH BRIEF
Pollution Prevention Assessment for a Manufacturer of
Metal Fasteners
Richard J. Jendrucko*, Thomas N. Coleman*, 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ment has been superseded by the Facility Pollution Prevention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
the University of Tennessee performed an assessment at a
plant that manufactures various types of metal fasteners for
automobiles, furniture, and appliances. Products are manufac-
tured from steel, brass, copper, and aluminum wire and rod
stock in two production lines—large part production and small
part production. In large part production, header machines
press wire stock into specific product shapes which are washed,
machined, and in some cases heat-treated and polished. Small
parts are manufactured from wire and rod stock in a series of
machining operations, then washed, heat treated and polished,
before shipment to an outside firm for surface finishing. The
team's report, detailing findings and recommendations indi-
cated that a large amount of plant oil waste is shipped off-site
for fuels blending and a significant quantity of oily sludge waste
is shipped offsite for disposal as non-hazardous waste. Large
cost savings can be achieved by the plant through the use of
alternative methods of removing metal chips from parts, thereby
reducing intermediate washings.
This Research Brief was developed by the principal investiga-
tors and EPA's National Risk Management Research Labora-
University of Tennessee, Department of Engineering Science and Mechanics.
University City Science Center, Philadelphia, PA.
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.
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 the University of
Tennessee's WMAC. The assessment teams have consider-
able direct experience with process operations in manufactur-
ing 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-
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ence for graduate and undergraduate students who participate
in the program, and a cleaner environment without more regu-
lations and higher costs for manufacturers.
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
The plant produces various types of metal fasteners for auto-
mobiles, furniture, and appliances. It operates 6,000 hr/yr to
produce over 100 million parts annually.
Manufacturing Process
The plant's products are manufactured from steel, brass, cop-
per, and aluminum wire and rod stock in two production lines—
large part production and small part production.
In the large part production line, wire stock is fed automatically
into header machines in which it is pressed into specific prod-
uct shapes. The formed parts are transported to a four-stage
aqueous parts washer where residual machining oils and metal
chips are removed. Then the cleaned parts undergo a series
of secondary machining operations including drilling, roll thread-
ing, and turning. Parts are rewashed during secondary ma-
chining in order to remove metal chips that could interfere with
subsequent machining steps. After machining is complete, the
parts are sent to auditing for inspection or to the heat treatment
area which includes a single-stage wash, a high temperature
heat-treat oven, an oil quench, and a draw furnace for stress
relief. Heat treated parts are polished in a vibratory finisher.
Finally, finished parts are inspected for defects, packaged, and
shipped to customers.
Small parts are manufactured from wire and rod stock in a
series of machining operations. The stock is drawn and sized
and fed into header machines where specific parts are formed.
The formed parts are cleaned in a two-stage drum washer
where residual lubricant and metal chips are removed. A series
of secondary operations, including drilling, tapping, and trim-
ming specific to the product being manufactured, completes
the required machining.
fere in subsequent machining steps. Then, parts are heat-
treated onsite, sent to an outside company for surface finish-
ing, or sent to auditing. Heat-treated parts are polished to
remove scale and sent to an outside company for surface
finishing. Finally, completed parts are inspected, packaged,
and shipped to customers.
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.
• An ultrafiltration unit is used to treat oil wastewater onsite.
Treated water is reused.
• Water is separated from waste oil in order to make the oil
usable for fuels blending offsite.
• A water evaporator is being installed to evaporate excess
wastewater that currently is shipped offsite for treatment.
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,
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 opportunity,
in most cases, results 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 chang-
ing emissions standards, liability, and employee health. It also
should be noted that the savings given for each pollution
prevention opportunity reflect the savings achievable when
implementing each opportunity independently and do not re-
flect duplication of savings that would result when the opportu-
nities are implemented in a package.
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 Emma
Lou George.
After most secondary operations, parts are rewashed in the
two-stage drum washer to remove metal chips that could inter-
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LARGE PARTS
Wire Stock
4-Stage Washing
Secondary Machining
4-Stage Washing
Heat Treating
Vibratory
Finishing
A uditing
Parts Packaged and
Shipped to Customers
SMALL PARTS
Wire and Rod Stock
Drawing and Sizing
\j
Headers
2-Stage Washing
Secondary Machining
2-Stage Washing
Heat Treating
Polishing
Shipped Offsite for
Surface Finishing
and Returned
Auditing
Figure 1. Abbreviated process flow diagram for metal fasteners manufacture.
Parts Packaged and
Shipped to Customers
Table 1. Summary of Current Waste Generation
Waste Generated
Source of Waste
Waste Management Method
Annual Quantity
Generated (Ib/yr)
Annual Waste
Management Cost
Petroleum naphtha
Oily sludge
Miscellaneous solid waste
Waste Oil
Scrap metal
Waste water
Machine part cleaning
Header clean-out
General plant operation
Machine clean-out and
wastewater treatment
Scraps and rejected parts
from all operations
Various processes
Shipped offsite for recycling 9,930
Shipped offsite as
nonhazardous waste 50,000
Shipped offsite to landfill 500,000
Shipped offsite for fuels blending 82,000
Shipped offsite for recycling Not available
Shipped offsite for treatment 448,200
$17,663
27,473
10,100
17,250
6,500
42,600
Includes waste treatment, disposal, and handling cost, and applicable raw material costs.
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Table 2. Summary of Recommended Pollution Prevention Opportunities
Annual Waste Reduction
Pollution Prevention Opportunity
Waste Reduced Quantity (Ib/yr) Percent
Net Annual
Savings
Implementation
Cost
Simple
Payback (yr)
Discontinue intermediate washing
between machining operations. As
an alternative, install lubricant baths
for dipping of parts for metal chip
removal.
Discontinue intermediate washing
between machining operations.
As an alternative, use compressed
air to blow off metal chips.
Eliminate the use of petroleum
naphtha for machine part cleaning.
Instead, use the 4-stage washer
for machine part cleaning. No
additional expense/waste is ex-
pected because of the low volume
of machine parts that require
washing.
Replace disposable paper towels
with cloth rags that can be
laundered onsite and reused.
Construct collection troughs around
leaky machines to reduce use of ab-
sorbent "socks" for containment of
leaks.
Utilize a cartridge filtration unit to
remove dirt and metal fines from
waste oil so that it can be reused
onsite as lubricating oil in the headers.
Wastewater
Wastewater
Miscellaneous solid
waste
Waste oil
224,100
224,100
Petroleum naphtha 9,930
Miscellaneous solid 25,000
waste
32,000
26,782
50
50
100
33
$19,173
19,173
15,663
11,579
8,424
6,693
$5,820
2,020
0.3
0.1
Immediate
5,400
2,000
1,500
0.5
0.2
0.2
1
Total annual savings have been reduced by an annual operating cost required for implementation.
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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EPA
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EPA/600/S-95/016
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