vvEPA
United States
Environmental Protection
Agency
Research and Development
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
EPA/600/S-92/057 October 1992
ENVIRONMENTAL
RESEARCH BRIEF
Waste Reduction Activities and Options for a
Manufacturer of Hardened Steel Gears
Alan Ulbrecht and Daniel J. Watts*
Abstract
The U.S. Environmental Protection Agency (EPA) funded a
project with the New Jersey Department of Environmental
Protection and Energy (NJDEPE) to assist in conducting waste
minimization assessments at 30 small- to medium-sized busi-
nesses in the state of New Jersey. One of the sites selected
was a facility that manufactures hardened steel gears of various
sizes and application. The manufacturing steps include grinding,
cutting, degreasing, and surface finishing. A site visit was
made in 1990 during which several opportunities for waste
minimization were identified. Options for pollution prevention
include changes in use of metal working coolants, degreasing
operations, and the rinsing procedures used in the plating
operations. Implementation of the identified waste minimization
opportunities was not part of the program. Percent waste
reduction, net annual savings, implementation costs and pay-
back periods were estimated.
This Research Brief was developed by the Principal Investiga-
tors and EPA's Risk Reduction Engineering Laboratory in Cin-
cinnati, OH, to announce key findings of this completed as-
sessment.
Introduction
The environmental issues facing industry today have expanded
considerably beyond traditional concerns. Wastewater, air
emissions, potential soil and groundwater contamination, solid
waste disposal, and employee health and safety have become
increasingly important concerns. The management and dis-
posal of hazardous substances, including both process-related
wastes and residues from waste treatment, receive significant
attention because of regulation and economics.
* New Jersey Institute of Technology, Newark, NJ 07102
As environmental issues have become more complex, the
strategies for waste management and control have become
more systematic and integrated. The positive role of waste
minimization and pollution prevention within industrial operations
at each stage of product life is recognized throughout the
world. An ideal goal is to manufacture products while generat-
ing the least amount of waste possible.
The Hazardous Waste Advisement Program (HWAP) of the
Division of Hazardous Waste Management, NJDEPE, is pursu-
ing the goals of waste minimization awareness and program
implementation in the state. HWAP, with the help of an EPA
grant from the Risk Reduction Engineering Laboratory, con-
ducted an Assessment of Reduction and Recycling Opportuni-
ties for Hazardous Waste (ARROW) project. ARROW was
designed to assess waste minimization potential across a
broad range of New Jersey industries. The project targeted 30
sites to perform waste minimization assessments following the
approach outlined in EPA's Waste Minimization Opportunity
Assessment Manual (EPA/625/7-88/003). Under contract to
NJDEPE, the Hazardous Substance Management Research
Center at the New Jersey Institute of Technology (NJIT) assisted
in conducting the assessments. This research brief presents
an assessment of the manufacturing of hardened steel gears
(1 of the 30 assessments performed) and provides recom-
mendations for waste minimization options resulting from the
assessment.
Methodology of Assessments
The assessment process was coordinated by a team of techni-
cal staff from NJIT with experience in process operations,
basic chemistry, and environmental concerns and needs. Be-
cause the EPA waste minimization manual is designed to be
primarily applied by the inhouse staff of the facility, the degree
of involvement of the NJIT team varied according to the ease
Printed on Recycled Paper
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with which the facility staff could apply the manual. In some
cases, NJITs role was to provide advice. In others, NJIT
conducted essentially the entire evaluation.
The goal of the project was to encourage participation in the
assessment process by management and staff at the facility.
To do this, the participants were encouraged to proceed through
the organizational steps outlined in the manual. These steps
can be summarized as follows:
• Obtaining corporate commitment to a waste minimization
initiative
• Organizing a task force or similar group to carry out the
assessment
• Developing a policy statement regarding waste minimiza-
tion for issuance by corporate management
• Establishing tentative waste reduction goals to be achieved
by the program
• Identifying waste-generating sites and processes
• Conducting a detailed site inspection
• Developing a list of options which may lead to the waste
reduction goal
• Formally analyzing the feasibility of the various options
• Measuring the effectiveness of the options and continuing
the assessment.
Not every facility was able to follow these steps as presented.
In each case, however, the identification of waste-generating
sites and processes, detailed site inspections, and development
of options was carried out. Frequently, it was necessary for a
high degree of involvement by NJIT to accomplish these steps.
Two common reasons for needing outside participation were a
shortage of technical staff within the company and a need to
develop an agenda for technical action before corporate com-
mitment and policy statements could be obtained.
It was not a goal of the ARROW project to participate in the
feasibility analysis or implementation steps. However, NJIT
offered to provide advice for feasibility analysis if requested.
In each case, the NJIT team made several site visits to the
facility. Initially, visits were made to explain the EPA manual
and to encourage the facility through the organizational stages.
If delays and complications developed, the team offered assis-
tance in the technical review, inspections, and option develop-
ment.
No sampling or laboratory analysis was undertaken as part of
these assessments.
Facility Background
The facility is a manufacturer of hardened steel gears of various
sizes for different types of applications. The facility purchases
steel and through grinding, cutting, and metal working forms
the parts into the desired shape. Subsequently, the surface is
treated to provide the expected level of hardening and wear
resistance.
The facility is located in an urban area and employs about 50
people.
Manufacturing Processes
The production of the hardened steel gears is a multi-step
process which involves a combination of mechanical metal
working processes and a series of surface modifications in
which chemical usage is required.
The first step in the production process requires the shaping of
the raw steel into gears of the desired size and configuration.
The shaping is accomplished by appropriate combinations of
cutting, grinding, and metal working. These steps typically
require the use of metal working coolants to facilitate process-
ing.
The next step is degreasing, required in order to remove any
material on the surface of the gear that might interfere with the
metal finishing. Degreasing is accomplished by first dipping the
gear into a vapor degreasing tank containing 1,1,1-
trichloroethane, drip draining the part over this tank, then dipping
the part into a hot alkaline cleaner using periodic reverse
electrical current for final grease removal. An additional afca-
line descaler with periodic reverse current is then used to
complete the cleaning process and any excess of the solution
is rinsed from the part using a hose over the tank.
The next step involves plating of the degreased gears with
copper using a copper cyanide bath at 150°F. The purpose of
the plating is to protect the surface from unwanted effects in
the final steps of the manufacturing process.
When necessary, the parts are dipped into black oxide for rust
resistance. This is followed by heat treatment which includes
carburizing, hardening, and nrtriding.
Following the heat treatment, the excess copper is deplated in
a sodium cyanide solution.
Existing Waste Management Activities
The manufacturing process generates three major waste
streams—the metal working coolants, the degreasing system
residues, and the rinses from the plating operations.
The metal working coolants are critical to successful metal
working by providing both lubrication and cooling of the metal
being worked and the tools being used. Individual metal work-
ing processes have been established using particular cooling
fluids, therefore there are several different types of coolants in
use at the facility. The coolant is typically an oil-water mixture.
The facility generates about 800 gal of waste coolants each
week that are sent for disposal offsite. The total waste volume
for lubricants and coolants is 40,000 gal.
The residues from degreasing consist of both chlorinated sol-
vents and aqueous residues. The aqueous residues come from
alkaline degreasing steps and are pH adjusted prior to disposal.
The organic and aqueous phases are separated before being
sent offsite for disposal. There remain traces of halogenated
solvent in the aqueous waste. About 7000 Ib of 1,1,1-
trtchtoroethane are sent offsite for disposal each year. It is
estimated that approximately another 3000 Ib are lost by
evaporation. Approximately 700 gal of aqueous waste are
generated each year.
The rinses from the plating operation include both copper and
cyanide constituents. The annual flow of this waste stream is
about 5.5 million gal and is sent to the POTW for disposal. The
waste from the deplating step is sent offsite for disposal. The
annual volume of this waste stream is about 2000 gal.
Waste Minimization Opportunities
The type of waste currently generated by the facility, the
source of the waste, the quantity of the waste and the annual
treatment and disposal costs are given in Table 1.
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Table 2 shows the opportunities for waste minimization recom-
mended for the facility. The type of waste, the minimization
opportunity, the possible waste reduction and associated sav-
ings, and the implementation cost along with the payback time
are given in the table. The quantities of waste currently gener-
ated at the facility and possible waste reduction depend on the
level of activity of the facility. All values should be considered
in that context.
It should be noted that the economic savings of the minimization
opportunity, in most cases, results from the need for less raw
material and from reduced present and future costs associated
with waste treatment and disposal, ft should also be noted that
the savings given for each opportunity reflect the savings
achievable when implementing each waste minimization op-
portunity independently and do not reflect duplication of savings
that would result when the opportunities are implemented in a
package. Also, no equipment depreciation is factored into the
calculations.
Regulatory Implications
There do not seem to be significant regulatory implications
which would hamper pollution prevention initiatives at this facil-
ity. However, international agreements addressing ozone
depletion and global warming may further inhibit the use of
1,1,1-trichloroethane. Also, 1,1,1-trichtoroethane is 1 of 17
chemicals which EPA has targeted under a voluntary program
with industry (the 33/50 Industrial Toxics Program) to reduce
releases to the environment. This program may lead to reduced
use of solvent. If additional regulations concerning use and
disposal of halogenated degreasers and metal plating residues
become effective, pollution prevention changes at this type of
facility will become even more important.
This Research Brief summarizes a part of the work done under
cooperative Agreement No. CR-815165 by the New Jersey
Institute of Technology under the sponsorship of the New
Jersey Department of Environmental Protection and Energy
and the U.S. Environmental Protection Agency. The EPA Project
Officer was Mary Ann Curran. She can be reached at:
Pollution Prevention Research Branch
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
* Mention of trade names or commercial products does not constitute endorsement
or recommendation for use.
Table 1. Summary of Current Waste Generation
Waste Generated
Source of Waste
Annual Quantity
Generated
Annual Waste
Management Costs
Metal Working Fluid
1,1,1-Trichloroethane
Aqueous Waste
1,1,1-Trichloroetharte
(air emissions)
Aqueous Waste
Aqueous Waste
Lubricant and coolant from
gear shaping operations
Degreasing operations
Degreasing operations
Degreasing operations
Rinses from plating operations
Copper deflating operation
40,000 gal
7,000 Ib
700 gal
3,000 Ib
5,500,000 gal
2000 gal
$40,000
3,200
1,200
(no direct costs)
1,700
7,000
•&U.S. GOVERNMENT PRINTING OFFICE: 1994 - 550-067/80179
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Table 2. Summary of Recommended Waste Minimization Opportunities
Waste Stream
Reduced
Minimization Opportunity
Annual Waste Reduction
Quantity Percent
Net Implementation Payback
Annual Savings Cost Years *
Metal Working Fluid
24,000 gal
60
$4000 $0 immed.
(The savings come from the difference
in treatment costs from a mobile fluid
recovery unit and from savings in
the purchase of new fluid.)
1,1,1-Trichloroethane
7,0001 b
100
17,000
Change practices to use a
single type of metal working
fluid throughout the facility.
This will permit the use of a
fluid reconditioning procedure to
facilitate the reuse of the material.
Such reuse will save on disposal
costs and material replacement costs,
but will incur some processing costs.
Explore possibility ofdegreasing
using only the alkaline decreasing
baths. If solvent degreasing is
still required, evaluate use of
non-halogenated alternatives such as
a terpene based material. If alternative
solvent is required, then savings will
be reduced.
If the vapor degreasing can be eliminated
there will be additional savings from
solvent losses to the atmosphere that will
no longer occur. Alternative technologies,
such as ultrasonics, should be explored.
Aqueous Rinse Waters Install new rinsing procedures, includ-
ing counter-flow rinses, and reuse of
highest concentration rinse water as
make-up water for the plating bath.
* Savings result from reduced raw material and treatment and disposal costs when implementing each minimization opportunity independently.
immed.
3,000 Ib
100
5,390,000 gal 98
2,000
1,650
3,000
immed.
1.8
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
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