vvEPA
United States
Environmental Protection
Agency
Research and Development
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
EPA/600/S-92/046 October
ENVIRONMENTAL
RESEARCH BRIEF
Waste Reduction Activities and Options for a Manufacturer of
Wire Stock Used for Production of Metal Items
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 as-
sessments at 30 small- to medium-sized businesses in the state of
New Jersey. One of the sites selected was a facility that manufac-
tures wire stock used for production of metal items. The facility
processes carbon steel and stainless steel coiled rods by cold
drawing them into smaller diameter wire which is sold as stock for
production of metal items such as ball bearings and springs. The
process involves several surface cleaning and preparation steps in
addition to simple cold drawing. A site visit was made in 1990 during
which several opportunities for waste minimization were identified.
Options identified included improvement of quality of acid wastes
leading to beneficial secondary use, and modification of rinsing
procedures to reduce fbw of wastewater. Implementation of the
identified waste minimization opportunities was not part of the pro-
gram. Percent waste reduction, net annual savings, implementation
costs and payback periods were estimated.
This Research Brief was devebped by the Principal Investigators
and EPA's Risk Reductbn 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
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
* New Jersey Institute of Technology, Newark, NJ 07102
wastes and residues from waste treatment, receive significant
attention because of regulation and economics.
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 preventbn 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) as-
sisted in conducting the assessments. This research brief
presents an assessment of manufacturing of wire stock used
for production of metal items (1 of the 30 assessments per-
formed) and provides recommendations 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-
Prmted on Recvc/ed Paper
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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
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 wire stock used for production
of metal items. The facility processes carbon steel and stain-
less steel coiled rods by cold drawing into smaller diameter
wire which is sold as stock for production of metal items such
as fasteners, ball bearings, hand tools, springs, welding rods,
and wire mesh. The entire process includes straightening and
cutting, descaling, shot blasting, degreasing, cleaning,
phosphating, and soap coating prior to the drawing and an-
nealing steps.
The facility is located in a suburban area and employs about
50 people. This facility uses well water as a source for the
water used in its processing and rinsing. The facility has on a
few occasions surpassed the limits for some metals set by the
POTW which receives its aqueous effluent. This concern con-
tributed to the decision to participate in a waste reduction
opportunity assessment.
Manufacturing Processes
The production of the drawn wire is fundamentally a three step
operation—cleaning the original steel rod, preparing the surface
for the cold drawing step, and carrying out the cold drawing.
The details are different for the two types of raw materials—
carbon steel and stainless steel. The first step—descaling— is
the same for both types of steel. The steel is placed in a tank
of 20% sulfuric acid heated to 160-185 °F and held there for
10-12 min.
For carbon steel rods, the next step is rinsing in a 1000-gal
tank where well water flows at a rate of about 50 gpm. The
rinsing is followed by a dip into a permanganate bath for
cleaning of organic contaminants, followed by submersion in a
hot water tank for preheating prior to precoating. The carbon
steel rods are precoated either by dipping in a 180°F zinc
phosphate bath or a sodium borate bath, depending upon the
ultimate use of the cold drawn product. After the pre-coating,
the rod coils are heated in a 212° F gas-fired oven for about 5
min. The coils are then dipped into a reactive soap bath to
neutralize the metal surface and treat it sufficiently to allow it to
hold stearate soap which is the lubricant for the cold drawing
process.
After the descaling step the stainless steel is dipped in a nitric
acid bath to passivate the metal surface. The pretreatment
step uses a borax-based soap solution rather than zinc phos-
phate or sodium borate used in the carbon steel process.
The facility also has an alkaline bath which is used to degrease
rejected wire prior to reprocessing.
It should be understood that these treatments are carried out
by dipping large, heavy coils of steel from one bath or container
to another. This is accomplished by a mechanical hoist system
which allows movement between the 15 tanks at the facility.
Existing Waste Management Activities
In spite of the number of different chemicals used in the
surface processing of the steel at this facility, there are only
two regularly produced waste streams: the spent sulfuric acid
from the descaling operations and the rinse-water which is sent
to the POTW. The other chemical baths are changed or cleaned
irregularly and cannot be quantified on an annual basis. Typically
they are used as dips and it is expected that the chemicals
contained will be incorporated onto the surface of the product.
The spent sulfuric acid from the descaling operation is pres-
ently sent offsite for disposal. The annual volume of this stream
is about 12,000 gal and disposal costs are $8300/yr. The spent
descaler has an acid concentration of 8% to 10% and an 8% to
10% iron concentration. There is also some zinc contained in
the solution. In the past this spent acid solution had been
accepted by a nearby chemical company for use in their
manufacturing operations. The company stopped accepting it
because of the presence of zinc.
The outflow of the rinse-water is adjusted to pH 6-9 with
anhydrous ammonia prior to sending to the POTW.
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As indicated above, rejected wire is reprocessed to the maxi-
mum extent which reduces the amount of waste generated by
the facility.
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 presents an interesting challenge in determining waste
minimization opportunities since at one time the major waste
stream, the spent sulfuric acid from the descaling operations,
was provided to another company for beneficial secondary
use. It is no longer acceptable to the second company due to
the presence of zinc in the solution. The waste minimization
challenge then was to determine the source of the zinc and to
suggest corrective action to keep it from the sulfuric acid bath.
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
opportunities, 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 op-
portunity independently and do not reflect duplication of savings
that would result when the opportunities are implemented in a
package.
The cost savings included waste disposal costs which are
avoided and the value of raw materials recovered. Equipment
depreciation is not factored into the calculations.
In attempting to determine the source of the zinc which had
begun to appear in the spent descaling baths, two likely sources
were postulated. Zinc could be contained in the steel rod which
was acquired as raw material for the wire-making process. For
example the steel might have been galvanized. This was con-
sidered to be unlikely because there had been no change in
suppliers between the time the zinc was found in the acid and
the previous times when there was no zinc in the solution. The
other possible source seemed to be the zinc phosphate bath
which was used for pre-coating some of the carbon steel
metal. With the information available, it was not obvious how
zinc from this bath would be transferred into the acid tank
because the zinc treatment step occurred after the descaling
process.
However, careful observation of the entire process suggested
that insufficient time was being allowed by the operators for
draining of solution from the coils before transferring them to
the next step in the process. This allowed the draining to
continue as the coils passed over other tanks including the
sulfuric acid descaling tanks. It is suggested, therefore, that
guidance be given to the operators to allow the appropriate
amount of drain time before moving the coil over top of any
other process tank. This should decrease any zinc content of
the sulfuric acid but also prevent the loss of materials from the
tanks unnecessarily.
Regulatory Implications
There do not seem to be significant regulatory implications of
pollution prevention initiatives at this facility. K is likely that
additional restrictions will be applied to the metal-containing
effluents going to the POTW in the future. In such a case, the
facility will have to enhance its testing of effluent in order to
assure that all emissions meet the additional requirements.
Testing may be utilized to maintain the quality of their spent
acid stream. This waste stream may be considered as a prod-
uct with QA/QC standards. Such standards and assurances to
the buyers of this material will encourage beneficial secondary
uses.
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
Sulfuric Acid Stream Spent acid from descaling step
Aqueous Effluent to POTW Rinse water after pH adjustment
with anhydrous ammonia
Annual Quantity
Generated
Annual Waste
Management Costs
12,000 gal
6,000,000 gal
$8300
2500
GOVERNMENT PRINTING OFFICE: 1994 - 550-067/80160
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Table 2. Summary of Recommended Waste Minimization Opportunities
Waste Stream
Reduced
Minimization Opportunity
Spent Acid Stream
Aqueous Effluent
Identify source of zinc in
the spent acid. If as expected
it results from too short drain
time, then operator training may
be effective. Zinc level reduction
should permit this stream to be used
again by another company as part of
one of their processes. A regular
analysis and quality control program
for this stream should build confidence
on the part of the buyer.
Determine whether the present flow
rate for the rinse is necessary
or can be reduced and still
maintain product quality. An
alternative may be to feed in a portion
of the pH adjusted effluent into the
rinse tanks. Any option such as this
will require some evaluation as to its
effect on the product.
Annual Waste Reduction
Quantity Percent
Net Implementation Payback
Annual Savings Cost Years *
12,000 gal
100
$8300
immed.
600,000 gal
10
(estimate)
250
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
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EPA/600/S-92/046
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