vvEPA
United States
Environmental Protection
Agency
Research and Development
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
EPA/600/S-95/006 April 1995
ENVIRONMENTAL
RESEARCH BRIEF
Waste Minimization Assessment for a Steel Fabricator
Marvin Fleischman*, Clay Hansen*,
Eric Daley**, 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. Waste Minimization Assessment Cen-
ters (WMACs) were established at selected universities and
procedures were adapted from the EPA Waste Minimization
Opportunity Assessment Manual (EPA/625/7-88/003, July 1988).
That document has been superseded by the Facility Pollution
Prevention Guide (EPA/600/R-92/088, May 1992). The WMAC
team at the University of Louisville performed an assessment
at a plant that manufactures carbon and stainless steel prod-
ucts, primarily conveying and transportation equipment. Raw
steel is cut, machined, welded into subassemblies, and sand-
blasted. Expanded metal is coated. All parts are painted, as-
sembled, inspected, packaged, and shipped. The team's report,
detailing findings and recommendations, indicated that the plant
could achieve significant cost savings and waste reduction by
replacing its current airless paint spraying system with a low
pressure, airmix system.
This Research Brief was developed by the principal investiga-
tors and EPA's Risk Reduction Engineering Laboratory, Cincin-
nati, 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.
Introduction
The amount of waste generated by industrial plants has be-
come an increasingly costly problem for manufacturers and an
* University of Louisville, Department of Chemical Engineering.
** University City Science Center, Philadelphia, PA.
^59 Printed on Recycled Paper
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
Risk Reduction Engineering Laboratory, the Science Center
has established three WMACs. This assessment was done by
engineering faculty and students at the University of Louisville's
WMAC. The assessment teams have considerable direct ex-
perience with process operations in manufacturing plants
and also have the knowledge and skills needed to minimize
waste generation.
The waste minimization 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 waste minimiza-
tion.
The potential benefits of the pilot project include minimization
of the amount of waste generated by manufacturers and re-
duction of waste treatment and disposal costs for participating
plants. In addition, the project provides valuable experience for
graduate and undergraduate students who participate in the
program, and a cleaner environment without more regulations
and higher costs for manufacturers.
Methodology of Assessments
The waste minimization assessments require several site visits
to each client served. In general, the WMACs follow the proce-
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dures outlined in the EPA Waste Minimization Opportunity
Assessment Manua/(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 supporting tech-
nological and economic information is developed. Finally, a
confidential report that details the WMAC's findings and recom-
mendations (including cost savings, implementation costs, and
payback times) is prepared for each client.
Plant Background
The plant manufactures carbon and stainless steel products,
primarily conveying and transportation equipment. It operates
approximately 2,040 hr/yr to process 1,500,000 Ib of raw steel
annually.
Manufacturing Process
The major raw materials used by the plant are stainless and
carbon steel. Additional components used include pumps, wheel
assemblies, controls and instrumentation, labels, and light as-
semblies.
Raw steel is cut by oxyacetylene gas torches, an automatic
plasma system, or a water cutting system. Bending, drilling,
turning, shaping, milling, punching, and sanding operations are
performed as required. Machined parts are welded and sand-
blasted.
Expanded metal is coated with Penetrol (rust preventative)
prior to joining raw steel parts in the paint area. Parts are
wiped down, primed, and painted with an airless spray system.
Painted parts undergo final assembly where additional compo-
nents are attached. These include pumps, assemblies, and
instrumentation.
The finished product is inspected and shipped. An abbreviated
process flow diagram is shown in Figure 1.
Existing Waste Management Practices
This plant already has taken the following steps to manage and
minimize its wastes:
Steel scrap is segregated by type and sold to a scrap dealer
for recycling.
A nonhazardous, biodegradable cutting fluid has replaced
the previously used 1,1,1-trichloroethane-containing cutting
fluid.
The plant is working directly with a paint manufacturer to
lower the barium concentration of the primer used.
The plant has set a goal to become a limited or zero quantity
generator by the first quarter of 1992.
Waste Minimization 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 waste management cost for each
waste stream identified are given in Table 1.
Table 2 shows the opportunities for waste minimization that the
WMAC team recommended for the plant. The minimization
opportunity, the type of waste, 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 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 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. 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 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.
Additional Recommendations
In addition to the opportunities recommended and analyzed by
the WMAC team, several additional measures were consid-
ered. These measures were not completely analyzed because
of insufficient data, minimal savings, implementation difficulty,
or a projected lengthy payback. Since one or more of these
approaches to waste reduction may, however, increase in
attractiveness with changing conditions in the plant, they were
brought ,to the plant's attention for future consideration.
Employ galvanic or cathodic corrosion protection to eliminate
the need for barium-based paint. Paint waste is currently
considered hazardous because the barium level exceeds the
allowableToxicity Characteristic Leaching Procedure (TCLP)
level.
Purchase a chip wringerto remove tramp oil from small metal
chips to prevent any future scrap metal recycling problems.
Attach a drip board to the Penetrol dip tank to reduce lost
dragout.
Build an enclosure for steel storage or set up sediment traps
with a weir system to eliminate storm water from washing oil
off the steel and into the ground.
Apply a polyurethane coat to the cement slab under the
maintenance vehicle gas pump to prevent spillage from
seeping through the cement and into the ground.
Use a paint dipping system for expanded metal and rails to
decrease the amount of paint overspray.
Use a solvent recirculating paint gun washer.
Give overpurchased paint to the community.
Use a variable aperture paint gun to apply paint to the rails.
Convince paint supplier to accept empty paint cans.
Improve plant layout to facilitate efficient collection and
segregation of wastes for recycle or pollution control.
Use a centralized coolant sump for individual machining
equipment.
Skim and filter coolant, regularly clean the sump, and main-
tain the proper coolant-to-water ratio.
Use acid treatment, ultrafiltration, centrifugation, coales-
cence, or evaporation for onsite treatment of coolant.
Replace disposable paint booth filters with dissolvable
styrofoam filters.
Compact short metal scrap to reduce the cost of transporting
to a recycler.
Use sand waste as a raw material in manufacture of rock
wool, as construction sand, or as an encapsulant for hazard-
ous waste disposal.
Sandblast in an enclosed or draped area to reduce disper-
sion of dust.
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Recycle empty sand bags. This research brief summarizes a part of the work done under
Investigate recycling of tires, pallets, batteries, and office Cooperative Agreement No. CR-814903 by the University City
Iff"; , . . , , . ., Science Center under the sponsorship of the U.S. Environmen-
Clean rags onsite instead of using an outside laundry service. tal Protection Agency. The EPA Project Officer was Emma
Lou George.
Raw steel
Expanded
metal
Cutting,
machining
Spent coolant
recycled
offsite
Coating
Arc
welding
Spent welding
rods and slag
Sandblasting
Parts
Spent
petroleum
naphtha
recycled
offsite
Painting
Final
assembly
Paint
overspray,
plastic, and
filters
Speny xylene
from paint gun
cleaning
recycled
offsite
Conveying and
transportation equipment
Figure 1. Abbreviated process flow diagram for conveying and transportation equipment manufacture.
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Modify the paint spray sys-
tem by using a low pressure, airmix system.
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Replace the naphtha-based parts washer
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gent. The proposed unit should include an
oil skimmer for oil removal; following skimm-
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Use di-basic esters instead of naphtha in
the parts washer. Di-basic esters have a
lower volatility than naphtha and are non-
toxic, thereby lowering costs associated
with evaporative losses and disposal. A di-
basic ester waste stream will be generated
if this WMO is implemented.
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Use cheese cloth pre-filters to cover
currently used paint booth filters. Because
cheese cloth is thinner than the filters.
the volume of waste to be disposed of
would decrease.
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Recover spent paint gun cleaning
solvent onsite using a batch distillation
unit. A small quantity of still bottoms
will be generated and shipped offsite
for disposal if this opportunity is
implemented.
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Use an electrostatic precipitator and a
filtering system to reclaim contaminated
hydraulic oil onsite for reuse. A small
quantity of residual dirt will be disposed
of offsite if this WMO is implemented.
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Replace the coolant with a biodegradable
and nonhazardous coolant. Purchase a
ultrafiltration unit to remove oils so that' the
spent coolant can be discharged to the
septic system. Oily residue will be shipped
offsite if this WMO is implemented.
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