United States
Environmental Protection
Agency
National Risk Management
Research Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-95/013 August 1995
ENVIRONMENTAL
RESEARCH BRIEF
Pollution Prevention Assessment for a Manufacturer
of Locking Devices
Richard J. Jendrucko*, Brian T. Hurst*,
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ment has been superseded by the Facility Pollution Prevention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). The WMAC team at the University
of Tennessee performed an assessment at a plant that fabri-
cates and finishes metal components that are assembled into
several types of locking devices. Raw materials are machined
and then shipped offsite for heat-treating, stored until needed,
or buffed and cleaned. Then, all parts other than those made
of stainless steel are electroplated, electrostatically powder
coated, or lacquer coated. The various component parts are
then assembled into the locking devices. The assessment
team's report, detailing findings and recommendations, indi-
cated that the vapor degreasers generate a significant amount
of waste and that vapor degreasing could be replaced with an
aqueous cleaning system for intermediate cleaning.
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.
University of Tennessee, Department of Engineering Science and Mechanics
" 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 the University of
Tennessee 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 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 preven-
tion.
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 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 fabricates and finishes metal components which are
assembled into several types of locking devices. Approxi-
mately one million units are produced annually by this plant
during 5,880 hr/yr of operation.
Manufacturing Process
The operations used by this plant are described below.
Component Parts Manufacturing
The major raw materials used by the plant include zinc die
castings and carbon and stainless steel, brass, and bronze in
bars, coils, and rods. Raw materials are moved by forklift to
the metal fabrication area where cutting, bending and shaping,
drilling, milling, screwing, and tapping operations are performed.
Prior to subsequent finishing operations, residual machining
lubricant is removed from the parts in one of two vapor
degreasers utilizing trichloroethylene. Contaminated trichloro-
ethylene is distilled onsite and reused.
After cleaning, the parts are processed in one of three ways.
Some of the steel parts are shipped offsite for heat treatment
and then returned to the plant for further processing. A portion
of the parts is placed into storage until needed for production at
a later time. The majority of parts which become external
locking device parts are buffed to improve their appearance,
either by hand or in an automatic system. Parts that have
been buffed are cleaned in a third vapor degreaser.
All parts except those made of stainless steel require a surface
coating. Most of the parts require one or more layers of
electroplating. The second major type of coating used is
electrostatic coating, and the third type is lacquer application to
prevent tarnishing.
After the necessary coating process is complete, the compo-
nent parts are transported to the assembly area where the
different locking devices are assembled and packaged.
Electroplating Operations
Because the electroplating operations generate a significant
amount of waste they are described in more detail in this
section.
Parts that are to be plated that have not been buffed are first
placed into vibratory devices for removal of any surface irregu-
larities. Those parts are then conveyed through a small vapor
degreaser, washed in a series of two wash tanks, and rinsed.
Three different plating lines are used by the plant. A small
quantity of special parts is plated in a small-scale hand-plating
line. Typical plating runs include chrome-or black chrome-,
bronze-, or brass-plating and hot water rinsing between each
plating stage and at conclusion.
Smaller parts that are used on the majority of the locking
devices are placed into barrels for plating in the barrel-plating
line. For corrosion protection, typical plating includes copper
striking and plating, dull and bright nickel plating, and chrome
plating with hot water rinsing between each stage and at a final
rinsing station.
Larger parts are placed onto racks and mechanically carried
through the rack-plating line. These parts are plated with zinc,
copper strike and plating, bronze, brass, nickel, and chrome for
decoration.
After parts have been processed through the appropriate plat-
ing line, they are removed from the conveying devices, allowed
to air dry, and carried to the assembly area.
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.
A filter press and a drying oven are used to reduce the volume
of hazardous wastewater treatment sludge shipped offsite.
Each vapor degreaser is served by a distillation unit for the
recycle and reuse of spent trichloroethylene.
Counterflow rinsing is used in the plating operations.
Flow restrictors have been installed on the water removal
lines of the electroplating rinse tanks to reduce the volume of
wastewater generated.
A compactor is used to reduce the volume of nonhazardous
solid waste shipped to the municipal landfill.
Water-based coolant and cutting oil is removed from metal
shavings using a centrifuge and returned to the metal fabri-
cation units.
Scrap metal shavings are recycled offsite.
Canvas coverings have been installed over the openings of
the vapor degreaser units to reduce evaporative losses of
solvent.
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 treatment and disposal 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
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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 opportu-
nity, in most cases, results from the reduction in raw material
and 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. It also should be noted that the
savings given for each opportunity reflect that pollution preven-
tion opportunity alone and do not reflect duplication of savings
that may result when the opportunities 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 a lack of
sufficient information for analysis or an anticipated lengthy
payback period. Since these approaches to pollution preven-
tion may, however, increase in attractiveness with changing
conditions in the plant, they were brought to the plant's atten-
tion for future consideration.
Install rinse devices above each plating and wash tank to
spray water onto each part as it is removed from the tank in
order to return plating and wash solutions to their tanks
before drag-out occurs. In order to compensate for the
increased amount of water being added to the tanks, it is
proposed that fan units be used to blow air across the surface
of each tank to promote evaporation of excess water. Drag-
out boards should be installed on each tank.
Implement electrostatic application of lacquer coating to
component surfaces to reduce the current level of overspray
and raw material purchases.
This research brief summarizes a part of the work done under
Cooperation 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.
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Metal
stock
Storage
^
Metal
fabrication
^
Vapor
degreasing
^
^
Finished locking
devices stored
until shipped
Electroplating
Electroplating
powder coating
Spray laquer
application
Figure 1. Abbreviated process flow diagram for locking device fabrication.
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Pollution Prevention Opportunity
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Discontinue the use of the primary vapor
degreasing unit for intermediate cleaning
during machining operations. Install an
aqueous cleaning solution system to re-
move lubricant residues and then dry the
parts with forced-air blowers. Secondary
degreasing units should be used for the
final removal of surface contaminants
prior to electroplating operations. A non-
hazardous water/detergent waste stream
will be generated if this opportunity is im-
plemented.
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United States
Environmental Protection Agency
National Risk Management Research Laboratory (G-72)
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/600/S-95/013
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