EPA
United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/M-91/017 Jul. 1991
ENVIRONMENTAL
RESEARCH BRIEF
Waste Minimization Assessment for a
Manufacturer of Rebuilt Railway Cars and Components
F. William Kirsch 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 hazardous waste but
lack the expertise to do so. Waste Minimization Assessment
Centers (WMACs) were established at selected universities
and procedures were adapted from the EPA Waste Minimiza-
tion Opportunity Assessment Manual (EPA/625/7-88/003, July
1988). The WMAC team at the University of Tennessee in-
spected a plant that rebuilds approximately 2,000 railway cars
(open, flat, and freight) each year and that refurbishes wheel
assemblies and air brake systems. The team's report, detailing
their findings and recommendations, indicated that the greatest
opportunities to minimize waste came from the railcar painting
operation where paint and primer solids and sludge are gener-
ated. The team recommended installing an electrostatic spray
paint system for priming and painting to reduce the overspray
losses.
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 the authors.
'University City Science Center, Philadelphia, PA 19104
Introduction
The amount of hazardous waste generated by industrial plants
has become an increasingly costly problem for manufacturers
and an additional stress on the environment. One solution to the
problem of hazardous waste 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 formation of hazardous waste but
lack the inhouse 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
Tennessee's (Knoxville) WMAC. The assessment teams have
considerable direct experience with process operations in
manufacturing plants and also have the knowledge and skills
needed to minimize hazardous 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 $50 million, employ no more than
500 persons, and lack inhouse expertise in waste minimization.
The potential benefits of the pilot project include minimization
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of the amount of waste generated by manufacturers, reduced
waste treatment and disposal costs for participating plants,
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-
dures outlined in the EPA Waste Minimization Opportunity
Assessment Manual (EPA/625/7- 88/003, July 1988). The WMAC
staff locates the sources of hazardous waste in the plant and
identifies 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 support-
ing technological and economic information is developed. Fi-
nally, a confidential report that details the WMAC's findings and
recommendations (including cost savings, implementation costs,
and payback times) is prepared for each client.
Plant Background
A waste minimization assessment was completed for a plant
that refurbishes railway cars, wheel sets, and air brake equip-
ment. The plant rebuilds approximately 2,000 railcars each
year.
Manufacturing Process
Several types of open, flat, and freight cars are received and
refurbished. The plant also rebuilds air brake systems and wheel
assemblies that are used on the railcars being refurbished or
that are shipped off-site to other facilities of this company.
The following steps are involved in the refurbishing
of railcars:
Mechanical cleaning of cars. Mechanical shakers
are used to loosen dirt and other residue from
the internal and external surfaces of the cars. The
debris falls through a grating in the floor and is
periodically collected and disposed of as
nonhazardous waste.
Secondary cleaning of cars. Cars are then
subjected to high-pressure water cleaning. The
spent water and residue resulting from the washing
is collected in a floor drain that leads to an outdoor
on-srte clarifier and pH adjustment facility. The
solids obtained by clarification are considered
non hazardous. Water is directed to the municipal
sewer.
Removing damaged parts and systems to be
replaced.
Removing paint coatings. A steel grit blast system,
which consists of an overhead motor-driven
impeller that slings the steel grit against the cars'
metal surfaces, removes paint chips. The paint
chips and grit are collected through a grating in the
floor and are conveyed to an outdoor cyclone
where reusable grit is recycled and paint dust and
spent grit are separated in a baghouse and
collected in barrels for off-site shipment as
hazardous waste.
Applying primer. After the stripping, primer is
applied with the use of hand-held spray guns.
Overspray, which collects on the walls and floor of
the primer area, is occasionally scraped off,
collected in barrels, and disposed of as hazardous
waste.
Reassembling cars. Repairs are made to the cars'
exteriors, and then the cars are reassembled.
Applying paint. Paint is applied with the use of
hand-held spray guns. Paint overspray on
the floor and walls is periodically scraped up and
disposed of as hazardous waste.
The wheel set rebuilding involves the following:
Resurfacing wheels. Wheel sets having no major
flaws are resurfaced on a lathe before being
reused.
Washing axles. Wheels having major flaws are
removed from their axles, collected, and sold as
scrap metal. Axles that can be recycled are washed
with a water-based caustic solution containing a
rust-preventative to remove grease and idrt.
Contaminated water is screened and sent to an
oil separator and then to the outdoor clarifier and
pH adjustment system. Sludge from the axle wash
system is collected in barrels and disposed of as
hazardous waste. Oil separated from water is
collected in barrels and sold to an outside
contractor.
Assembling wheel sets. New wheels are joined to
the recycled axles.
Air brake rebuilding involves the following:
• Removing external debris. A plastic bead blast
system removes external debris from the air
brake assemblies. Spent beads and debris are
collected in barrels and shipped off-site as
hazardous waste.
Solvent cleaning. The air brakes are disassembled
and cleaned with solvents. A vendor supplies the
cleaning solvents and is responsible for periodically
renewing the solvents and for removing spent
solvents.
Reassembling air brake systems.
Existing Waste Management Practices
This plant has discontinued using methylene chloride in the axle
wash process, installed a wastewater treatment facility, and
contracted with an outside supplierto reclaim solvent used in air
brake component cleaning in order to minimize and manage its
hazardous wastes.
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Waste Minimization Opportunities
The type of waste currently generated by the plant, 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 that the
WMACteam recommended for the plant. The type of waste, the
minimization opportunity, the possible waste reduction and
associated savings, and the implementation cost along with the
payback time are given in the table. The quantities of hazardous
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, in most cases, the economic savings of
the minimization opportunities result from the need for less raw
material and from reduced present and future costs associated
with hazardous 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 should also be noted that the savings given
for each minimization opportunity reflect the savings achievable
when implementing each opportunity independently and do not
reflect duplication of savings that would result when the waste
minimizations opportunities are implemented in a package.
Additional Recommendations
In addition to the opportunities recommended and analyzed by
the WMACteam, several additional measures were considered.
These measures were not analyzed completely because of
insufficient data, implementation difficulty, or a projected lengthy
payback as indicated below. Since one or more of these ap-
proaches to waste reduction may, however, increase in attrac-
tiveness with changing conditions in the plant, they were brought
to the plant's attention for future consideration.
Those additional recommendations include:
Install a custom-designed system in the grit blast
area to effect a separation of spent steel grit and
paint residue. To the extent the two materials can
be separated, the volume of hazardous waste
(paint and spent contaminated steel grit) can be
reduced by the amount of the spent steel grit, that
is not hazardous. Concepts for the paint and steel
separation include the use of an electromagnet or
flotation system. Since such systems would be
capital intensive in relation tothe savings, payback
is not attractive at this time.
Use a mechanical axle precleaning before the
caustic wash. By using mechanical brushing, some
relatively dry residue can be removed from the
axles in a concentrated form for disposal rather
than as part of the sludge obtained from the
present wash system. Technical difficulties may
be associated with oil or grease contamination of
a rotating brush, and savings would likely be small
and payback lengthy at this time.
Install an ultrasonic axle wash system to eliminate
the caustic wash waste water stream. This measure
would be relatively capital intensive and would
have a lengthy payback.
Eliminate air drafts in railcar painting sheds to
minimize primer and paint mist being blown away
from the surfaces to which the spray is directed.
On windy days, aircurrentsthrough the paint shed
areas are apparently responsible for a significant
amount of the overspray waste. Because of the
limited time to observe these effects, it was not
possible to quantify potential waste reduction.
This Research Brief summarizes a part of the work done under
Cooperative Agreement No. CR-814903 by the University City
Science Center under the sponsorship of the U.S. Environmen-
tal Protection Agency. The EPA Project Officer was Brian A.
Wesfall.
The EPA contact, Emma L. George, 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
Paint chips and spent steel grit
Paint and primer solids and sludge
Evaportaed solvents
Axle wash sludge
Paint chips and spent plastic beads
Steel grit blast system.
Railcar painting operation.
Railcar painting operation.
Axle cleaning operation.
Brake component cleaning operation.
Annual Quantity
Generated
225 ton1
214 ton2
56,042 Ib
6,000 gal
2,400 Ib
900 Ib
Annual Waste Mangement
Cost
$95,560
36,860
O3
5,350
5,200
1 Steel grit
2 Paint chips
3 Currently, the plant reports no waste management costs associated with the evaporation of the solvents.
•&U.S. GOVERNMENT PRINTING OFFICE: 1991 - 548-02H/40037
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Table 2. Summary of Recommended Wa»te Minimization Opportunities
Waste Generated Minimization Opportunity
Annual Waste Reduction Net Annual
Quantity Percent Savings
Implementation Payback
Cost Years
Paint and primer
solids and sludge
and evaporated
solvents
Dirt contaminated
with paint and primer
Paint chips and
spent steel grit
Install an electrostatic spray 580 gal1
paint system for priming arid 85 gal2
painting to reduce overs pray
losses.
Retrain paint personnel to 197 gal1
improve spray technique and 300 gal2
thus reduce overspray losses.
Cover dirt floors of the paint 2,802 Ib
and primer areas with plastic
sheets to collect paint and
primer residue. Currently 10%
of the paint and primer waste
removed is dirt.
Modify the blast operation to 37 ton3
remove 75% of coating rather 36 ton4
than the current 90%. Plant
personnel have indicated that
it is possible to remove less of
the coatings without a detri-
mental effect on product quality.
15
1
$11,080s*
4,820s
1.540s
$58,320
3,500
O7
5.3
0.7
17
17
24.980s
13,500
0.5
Paint and primer
Solvent
Steel grit
Paint chips
Includes savings on raw materials
Total savings reducted by annual operating cost
Implementation requires annual operating cost but no capital cost
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA PERMIT NO. G-35
Official Business
Penalty for Private Use $300
EPA/600/M-91/017
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