f,EPA
United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-92/064 October 1992
ENVIRONMENTAL
RESEARCH BRIEF
Waste Reduction Activities and Options for a
Manufacturer of Orthopedic Implants
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 orthopedic implants for use by
the health care industry. The parts are produced in a molding
operation using stainless steel or cobalt chromium alloy. Com-
puter-controlled cutting is used to produce the bearings for the
implants according to precise specifications. A site visit was
made in 1990 during which several opportunities for waste
minimization were identified. Options identified include onsite
distillation and reuse of solvent, alternative degreasing tech-
niques, and reuse of metal cutting fluids. Implementation of the
identified waste minimization opportunities was not part of the
program. Percent waste reduction, net annual savings, imple-
mentation costs and payback 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 regulatbn 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 orthopedic implants for
use by the health care industry (1 of the 30 assessments
performed) and provides recommendations for waste minimi-
zation 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, NJIPs 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 orthopedic implants for the
health care industry. Specific products include hip, shoulder,
and knee replacements made from stainless steel or cobalt
chromium alloys. The products are made through a molding
operation with machining of precision bearings.
The facility, located in a suburban area, employs about 50
people and has been in its present location approximately 20
years.
Manufacturing Processes
The production of the orthopedic implants is in essence a 3-
step process. Initially, a wax prototype with the desired size
and shape of the finished implant is prepared and all imperfec-
tions are repaired with an alcohol treatment. The wax is then
coated and gradually a shell is built up with a slurry of colloidal
silica. The finished shell is dried in an oven to produce a
ceramic mold.
The ceramic is then seal-coated with more silica and then
placed in an oven to melt and drain the inner wax and to
complete hardening of the outer shell. A hole is cut in the
ceramic shell to allow draining of the wax and covered with a
plastic plug to prevent dirt and other contamination from entering.
An ingot of either cobalt chromium or stainless steel is melted
in an electric inductive furnace. The plastic cap is removed
from the ceramic mold and the molten metal is poured into the
ceramic cavity. When the metal hardens, the ceramic shell is
chipped away and the solid metal implant remains.
The bearings for the implants are cut to precise and specific
tolerances using a computer numerical control production ma-
chine. Excess water soluble lubricants used in this process are
removed in a 1,1,1-trichloroethane vapor degreasing tank, the
implant is stencilled for identification, and packaged in plastic
in a clean room for shipment to the customer.
Existing Waste Management Activities
The company has already begun consideration of pollution
prevention options to be used in its processes. One example of
this consideration is an examination of the possibility of using
terpene-based degreasers in place of the chlorinated solvent
currently used.
Denatured alcohol is currently used for working the wax molds.
Annually about 165 gal of this solvent are sent offsite for
recycling or for recovery of fuel value.
From the numerically controlled metal machining process 1,155
gal of water soluble oils and 770 gal of petroleum-based oils
are generated annually. They are sent offsite for recycling or
fuel value recovery.
From the vapor degreaser, 770 gal of 1,1,1-trichloroethane is
sent offsite for disposal each year. Approximately 400 gal is
lost annually as fugitive emissions.
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. This particular
facility is kept scrupulously clean and illustrates that production
of critical medical products can generate hazardous waste and
benefit from pollution prevention initiatives.
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.
It should be noted that the economic savings of the minimiza-
tion opportunity, in most cases, results from the need for less
raw material and from reduced present and future costs asso-
ciated with waste treatment and disposal. It should also be
noted that the savings given for each opportunity reflect the
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savings achievable when implementing each waste minimiza-
tion opportunity independently and do not reflect duplication of
savings that would result when the opportunities are imple-
mented in a package. Also, no equipment depreciation is
factored into the calculations.
Regulatory Implications
There are no significant regulatory issues which would impede
the introduction of further pollution prevention concepts at this
facility. Increased regulatory concern about releases of chlori-
nated hydrocarbons may accelerate the investigation of pos-
sible use of terpenic or alkaline aqueous degreasing systems.
Use of terpenic material for this purpose may eventually raise
* Mention of trade names or commercial products does not constitute endorsement
or recommendation for use.
questions about the advisability of discharging such materials
to a POTW, even though they are usually naturally occurring
materials.
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
Table 1. Summary of Current Waste Generation
Waste Generated
Source of Waste
Annual Quantity
Generated
Annual Waste
Management Costs
Chlorinated Solvent
Effluent from vapor degreaser
770 gal
$2,450
Chlorinated Solvent
Denatured Alcohol
Water Soluble Oils
Petroleum Oils
Evaporative losses from
solvent degreaser
Wax mold working
Metal machining
Lubrication
400 gal
165 gal
1155 gal
770 gal
2,600
(raw material loss)
525
3,675
2,450
•U.S. Government Printing Office: 1992 — 648-080/60125
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Table 2. Summary of Recommended Waste Minimization Opportunities
Waste Stream
Reduced
Chlorinated Solvent
Denatured Alcohol
Water Soluble Oils
Minimization Opportunity
Acquisition of onsite distilla-
tion equipment to recycle
and reuse degreasing solvents.
Continue investigation of change
to alkaline aqueous based or
terpene based degreasers. Ultra-
sonic bath in combination with
the alkaline aqueous based degreaser
may be most effective.
Recycle and reuse this solvent by
onsite distillation.
Segregate and use onsite recovery
and recycling service.
Annual Waste Reduction
Quantity Percent
616 gal
1170 gal
132 gal
925 gal
80
100
80
80
Net Implementation Payback
Annual Savings Cost Years'
$5,960
9,957
820
2,940
$4,000
3,500
0.6
0.3
4,000
5.0
immed
* Savings result from reduced raw material and treatment and disposal costs when implementing each minimization opportunity independently.
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
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EPA
PERMIT No. G-35
EPA/600/S-92/064
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