svEPA
United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-92/051 October 1992
ENVIRONMENTAL
RESEARCH BRIEF
Waste Reduction Activities and Options for a
Remanufacturer of Automobile Radiators
Kevin Gashlin 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 remanufactures automobile radiators. The
process involves cleaning the radiator, locating and repairing
any leaks, painting, and reinstallation. A site visit was made in
1990 during which several opportunities for waste minimization
were identified. Options identified include changes in the
cleaning procedure, more efficient rinsing operations, and
change of paint from solvent-based to water-based. Implemen-
tation of the identified waste minimization opportunities was not
part of the program. Percent waste reduction, net annual sav-
ings, implementation costs and payback periods were estimated.
This Research Brief was developed by the Principal Investigators
and EPA's Risk Reduction Engineering Laboratory in Cincinnati,
OH, to announce key findings of this completed assessment.
Introduction
The environmental issues facing industry today have expanded
considerably beyond traditional concerns. Wastewater, air emis-
sions, potential soil and groundwater contamination, solid waste
disposal, and employee health and safety have become increasingly
important concerns. The management and disposal of hazardous
substances, including both process-related wastes and residues
from waste treatment, receive significant attention because of regu-
lation and economics.
As environmental issues have become more complex, the strategies
for waste management and control have become more systematic
* New Jersey Institute of Technology, Newark, NJ 07102
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 generating the least amount of waste possible.
The Hazardous Waste Advisement Program (HWAP) of the Divi-
sion of Hazardous Waste Management, NJDEPE, is pursuing 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, conducted an Assessment of
Reduction and Recycling Opportunities for Hazardous Waste (AR-
ROW) 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
folbwing the approach outlined in EPA's Waste Minimization Op-
portunity 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 as-
sessment of the remanufacturing of automobile radiators (1 of the
30 assessments performed) and provides recommendations for
waste minimization options resulting from the assessment.
Methodology of Assessments
The assessment process was coordinated by a team of technical
staff from NJIT with experience in process operations, basic chem-
istry, and environmental concerns and needs. Because 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 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.
Printed on Recycled Paper
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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 techni-
cal staff within the company and a need to develop an agenda for
technical action before corporate commitment 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 compli
cations developed, the team offered assistance in the technical
review, inspections, and option development.
No sampling or laboratory analysis was undertaken as part of these
assessments.
Facility Background
The facility refurbishes motor vehicle radiators, both from automo-
biles and from heavier commercial vehicles. In a real sense, this
type of facility is in the pollution preventbn business by extending
the useful life and allowing reuse of equipment which otherwise
would find its way into the waste stream. The process used involves
removal of the radiator from the vehicle, cleaning the radiator, finding
and repairing any leaks, painting, and reinstallation into the vehicle
This facility is located in an urban area and employs about 20
people.
Remanufacturing Process
The remanufacturing process is conceptually simple—the radiator is
removed from the vehicle, cleaned, leaks detected and repaired,
painted, and reinstalled in the vehicle. These individual steps however
have potential for waste generation and each requires separate
consideration from a pollution preventbn perspective.
The removal process has potential for generation of waste streams
by capturing freon from air conditioning equipment in the vehicles
and from collecting ethylene glycol antifreeze contained in the
radiators.
The cleaning process is rigorous. The radiator is immersed in a tank
of caustic solution (typically 40% to 50 % sodium hydroxide) which is
heated to 140-200 °F. The radiator remains in this tank, frequently
called a boil-out tank, for 15 to 60 min. The objective of this cleaning
step is to soften or remove deposits, scale, corrosion, or other
foreign materials from the radiator. After the cleaning, the radiator is
removed from the boil-out tank and the caustic solutbn is allowed to
drain. The radiator is then rinsed using approximately 5-10 gal of
water in a rinse tank. This rinsing is most frequently accomplished
using a flow through system with fresh tap water. The primary
objective of this step is to remove adhering caustb solution and any
bosened scale from the inside and outside of the radiator.
The rinsed radiator is leak tested in a test tank. Leak testing involves
hooking a compressed air line to one end of the radiator, plugging
the other end, and submerging the radiator in the test tank. Leaks
are located by the stream of bubbles which appear in the water and
are repaired by soldering. The soldering involves application of a flux
or muriatb acid to prepare the surface, followed by spot heating and
application of the solder. The soldering usually takes place while the
radiator is supported on a rack over the test tank.
After leak repairs are completed, the radiator is painted using a
solvent-based black enamel paint and reinstalled in the vehicle. The
painting is done in a spray booth.
Existing Waste Management Activities
At the time of the assessment, the facility had questbns about its
waste management practbes and an interest in exploring pollutbn
prevention options. At the time of the assessment, the freon from the
air conditioning system was vented to the atmosphere when the
radiator was removed from the vehicle. Similarly, the engine coolant
was discharged to the POTW. No information was available about
the quantity of this material whbh was generated. Following the
assessment, the freon is captured, purified and reused onsite.
Similarly, the antifreeze solutbn is collected and recycled. Although
these streams are peripheral to the radiator remanufacturing, the
changes represent advances in pollutbn prevention at the facility.
Data to measure the impact of these changes is not yet available.
The boil-out tank generates waste whbh can be described as a
highly alkaline sludge containing heavy metals. The usual practice is
to dump the boil-out tank when the build up of sludge on the bottom
is sufficient to interfere with the insertion of the radiator. In addition,
the supernatant liquid from the boil-out tank is periodically partially
discharged to the POTW. Both the sludge and the aqueous discharge
are highly alkaline and the metal content frequently exceeds the
limits acceptable for discharge. The sludge accumulates at the rate
of about 3 drums per year and is sent for land disposal. It was not
possible to determine the volume of the discharge to the POTW.
The flow through the rinse tank is estimated to be about 300 gal of
water per day. This flow is discharged to the POTW and any sludge
which is collected in the tank is combined with the sludge from the
boil-out tank for disposal. The test tank, about 30 gal, is dumped to
the POTW whenever it becomes so cbudy as to prevent easy
detectbn of leaks. The frequency of dumping depends upon the use
of the tank, and to a very large extent the turbidity of the test tank
depends upon the effectiveness of the preceding rinsing step. The
test tank is dumped about once each month. Any sludge in this tank
is also collected and combined with the boil-out tank sludge.
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The radiators are spray painted with solvent-based paint. Approxi-
mately 600 gal of paint at 63% solvent levels is used annually. This
means that 378 gal of solvent is released to the atmosphere. The
fitters from the spray booth which captured overspray were dried
and sent for disposal as non-hazardous waste.
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.
Table 2 shows the opportunities for waste minimization recom-
mended for the facility. The type of waste, the minimization opportu-
nity, the possible waste reduction and associated savings, and the
implementation cost along with the payback time are given in the
table. The quantities of waste currently generated at the facility and
possible waste reduction depend on the level of activity of the facility.
ft 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. It should also be noted that the
savings given for each opportunity reflect the savings achievable
when implementing each waste minimization opportunity indepen-
dently and do not reflect duplication of savings that would result
when the opportunities are implemented in a package.
The cost savings are calculated both in terms of avoided costs of
waste disposal and recovery of any value of raw material used
again. Also, no equipment depreciation is factored into the calcula-
tions.
This facility affords two areas of opportunity for pollution preven-
tion—the painting area and the water quality and quantity manage-
ment area.
At the time of the assessment two types of options were developed
for the painting process—improve the spray procedure to reduce the
volume of overspray and use a water-based paint to paint the
remanufactured radiators. There was no water-based paint available
for this purpose. Since the assessment, however, the facility has
discovered, evaluated, and adopted for use a water-based latex
paint. The change was not without difficulty, however, because
some of the customers of the business complained that they had
received an inferior paint job because the appearance was not the
same as that of previous jobs. This was overcome through discus-
sion and education with the customers.
The water management problem is somewhat more complex. Two
types of concern are the pH of the system and the metal content of
the system. In addition there is an interest in reducing the volume of
sludge which the remanufacturing process generates. To a large
degree reduction of the quantity of sludge is independent of the
process used because it results from the cleaning of foreign materi-
als from the used radiators which are processed through the facility.
One approach to reducing the boil-out tank problem is to eliminate
that process entirely. An alternative process called "rodding" is
essentially a manual reaming. This coupled with mechanical and
spot cleaning has been used in some similar facilities in place of the
boil-out tank. This alternative eliminates the boil-out and rinse tank
difficulties.
If it is decided to continue with the caustic boil-out tank approach,
then the goal should be to reduce the total water usage. One way to
accomplish this is to develop a counter-flow rinsing technique which
would require the addition of at least one more tank The objective
would be to keep as much active chemical in the boil-out tank as
possible. The modification to the present procedure would involve
increased attention to remove as much caustic solution as possible
when the radiator is removed from the bath. This would mean
increased drip time to albw as much liquid as possible to drip back
into the boil-out tank. In addition, it would be desirable to use
compressed air to force out as much of the liquid as possible which
may be inside the radiator.
This nearly drip-free unit should be placed in the rinse tank and
rinsed in the usual way. The dripping and air-forcing procedure
should be repeated here. The rinsed radiator should then be immersed
in a newly added tank, which can be termed a drag-out tank for
further removal of contaminants. Following this step, again with
appropriate drip time and conditions, the radiator can be placed in
the leak detection tank.
To make this system most effective, the water from lightly contami-
nated tanks would be used as make-up water for more heavily
contaminated tanks. For example, because the boil-out tank is
heated, water is tost through evaporation. Water from the rinse tank
can be used to replace that tost water in the boil-out tank. The drag
out tank water can be used to refill the rinse tank, and the leak tank
can be used to refill the drag out tank. Tap water should be used
only in the leak tank. If sludge or solids appears in any of the tanks
except the boil out tank, it can be removed by a simple f iltratton prior
to transferring the water to the next tank.
This approach concentrates the metals and caustic in the boil out
tank and maintains relatively constant levels in the other tanks. This
process eliminates much of the discharge to the POTW. In order to
make this practicable, it is necessary to avoid contamination of these
tanks with other materials. For example, the practice of soldering the
radiators while they rest over the leak tank should be stopped. This
approach allows flux and solder to drop into the tank, contaminating
the water. The soldering should be done elsewhere where the
residues can be captured and handled more appropriately. Ideally, a
non-lead solder with the necessary performance characteristics
should be identified and used.
Table 1. Summary of Current Waste Generation
Waste Generated Source of Waste
Alkaline Metal-Contain-
ing Sludge
Solids from boil-out tank and
from rinse and leak tanks
Volatile Solvents
Drying of solvent-based paint
Annual Quantity
Generated
3 drums
Aqueous Waste to POTW Flowthrough from rinse tank and 100,000 gal
occasional discharge from other tanks (estimate)
378 gal
Annual Waste
Management Costs
$1,650
30
(no direct
treatment costs)
6U.S. GOVERNMENT PRINTING OFFICE: 1994 - 550467/80189
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Table 2. Summary of Recommended Waste Minimization Opportunities
Waste Stream
Reduced
Minimization Opportunity
Annual Waste Reduction Net Implementation Payback
Quantity Percent Annual Savings Cost Years *
Alkaline Metal-
Containing Sludge
POTW Discharge
Convert to rodding and mechan-
ical cleaning. This approach
also eliminates much discharge to
POTW.
Implement counterflow rinsing
and tank refill procedures
leading to zero discharge.
3 drums
100
$1,650 $200 0.1
(It should be recognized that this
technique does produce solid waste
which must be managed and the approach
is highly labor intensive.)
100,000 gal 100
30
25,000
(estimate)
833
Volatile Solvents
Change to water-based paints
378 gal
100
(This option must be considered not in light of
current management costs, rather it should be
compared with pretreatment costs for the entire
POTW discharge which likely would soon be
required for facilities of this type to remain
in operation. This cost would be expected to
be substantially higher than the option addressed
here.)
0 0 none
(This option represents essentially no net savings
and no net cost, but is a positive pollution
prevention initiative.)
* Savings result from reduced raw materials and treatment and disposal costs when implementing each minimization opportunity independently.
Where the loss of water by evaporation from the boil-out tank is not
rapid enough to allow the levels of contaminants in the other tanks to
remain in a workable range, it may be necessary to treat the rinse
water. This may be as simple as addition of a storage/settling tank
for the rinse water or may get more complex depending upon
conditions at the individual facility. Monitoring of pH and acid addition
to maintain neutrality may be necessary.
When it is necessary to remove sludge from the boil-out tank, it is
suggested that the tank contents be filtered, the solids dried or
compressed and the liquid returned to the tank for reuse. The solids
should be disposed of as hazardous waste, or more preferably, sent
to a secondary recovery facility to reclaim the metal values.
Regulatory Implications
There are no significant regulatory issues which would impede
the implementation of pollution prevention initiatives at this facility. In
fact, in view of the occasional exceedance of acceptable limits to the
POTW, it is likely that the facility would have to install some type of
pretreatment capability. Acceleration of identification and implemen-
tation of pollution prevention practices may albw the facility to avoid
the need for pretreatment by eliminating discharges to the POTW. It
is expected that the process alterations to accomplish the pollution
prevention approach would be substantially less costly than installation
of a pretreatment capability.
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.
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
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