&EPA
United States
Environmental Protection
Agency
National Risk Management
Research Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-95/031 August 1995
ENVIRONMENTAL
RESEARCH BRIEF
Pollution Prevention Assessment for a
Manufacturer of Components for Outboard Motors
Richard J. Jendrucko*, Thomas N. Coleman*,
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. In an effort to assist these manufactur-
ers Waste Minimization Assessment Centers (WMACs) were
established at selected universities and procedures were
adapted from the EPA Waste Minimization Opportunity As-
sessment Manual (EPA/625/7-88/003, July 1988). That docu-
ment has been superseded by the Facility Pollution Prevention
Guide (EPA/600/R-92/088, May 1992). The WMAC team at
the University of Tennessee performed an assessment at a
plant that manufactures power heads and midsections for use
in marine outboard motors. Aluminum castings undergo metal
working, chromate conversion, spray painting, and assembly
operations. The team's report, detailing findings and recom-
mendations, indicated that a large amount of wastewater from
the chromate conversion of raw aluminum castings is gener-
ated and that significant cost savings and waste reduction
could be achieved by recycling the wastewater using a reverse
osmosis system.
This Research Brief was developed by the principal investiga-
tors and EPA's National Risk Management Research Labora-
tory, Cincinnati, 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
additional stress on the environment. One solution to the
* University of Tennessee, Department of Engineering Science and Mechanics
* University City Science Center, Philadelphia, PA
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
National Risk Management Research Laboratory, the Science
Center has established three WMACs. This assessment was
done by engineering faculty and students at the University of
Tennessee's WMAC. The assessment teams have consider-
able direct experience with process operations in manufactur-
ing plants and also have the knowledge and skills needed to
minimize waste generation.
The pollution prevention opportunity 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 pollution
prevention.
The potential benefits of the pilot project include minimization
of the amount of waste generated by manufacturers, and
reduction of waste treatment and disposal costs for participat-
ing plants. In addition, the project provides valuable experi-
ence for graduate and undergraduate students who participate
in the program, and a cleaner environment without more regu-
lations and higher costs for manufacturers.
Methodology of Assessments
The pollution prevention opportunity assessments require sev-
eral site visits to each client served. In general, the WMACs
follow the procedures outlined in the EPA Waste Minimization
Printed on Recycled Paper
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Opportunity Assessment Manual (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 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
The plant manufactures power heads and midsections for use
in marine outboard motors from aluminum castings. It oper-
ates 6,000 hr/yr to produce approximately 200,000 units annu-
ally.
Manufacturing Process
Power heads and midsections are produced by this plant and
shipped to another plant owned by the same company to be
assembled into the final consumer product, outboard motors.
Raw materials used by the plant include aluminum castings
such as motor blocks and heads, steel flywheels, and connect-
ing rods. The operations of this plant include metal working,
chromate conversion of raw aluminum castings, spray painting,
and final assembly.
Raw aluminum castings and chrome-converted aluminum cast-
ings are received and stored temporarily prior to being used in
production operations. The castings are transferred to a chrome
conversion or spray painting operation, or to a series of ma-
chining operations. Each part will undergo chrome conversion,
painting, and metal working, but the sequence of the opera-
tions is determined by the production line.
Residues from machining are cleaned from parts (such as
heads, blocks, and manifolds) in aqueous washers dedicated
to each production line. After cleaning, the parts are bolted
together in a series of assembly operations. The finished
power heads and midsections are tested, and accepted prod-
ucts are shipped to the assembly plant.
The chrome conversion and spray painting operations are
described below.
Chrome Conversion
The chrome conversion process provides a protective surface
finish to raw aluminum castings. Initially, parts are washed and
rinsed and their surfaces are chemically etched in an acid bath.
Then the parts are rinsed twice and submersed in a chromic
acid bath in which the surface metal is oxidized to form a
corrosion-resistant protective finish. Chromic acid residue re-
maining on the surfaces of the parts is removed in three final
rinses.
Spray Painting
Parts receive a protective coating of black paint in the spray
painting operation. The parts to be painted are placed on
hangers attached to an overhead conveyor. Masking is ap-
plied manually to surfaces that do not require painting. Paint is
applied to the parts using a hand-held electrostatic spray gun
as they travel through the spray painting booth. Following
paint application, the coating is cured in an oven and then the
masking is removed.
A simplified process flow diagram for this plant is shown in
Figure 1.
Chrome-finished
Aluminum Castings
Raw Aluminum
Castings
Chrome-Finished
Aluminum Castings,
Fasteners,
Iron Sleeves
Figure 1.
Outboard Motor Components Shipped
Simplified process flow diagram for manufacture of outboard
motor components.
Existing Waste Management Practices
This plant already has implemented the following techniques to
manage and minimize its wastes:
• Wet/dry vacuums have replaced the use of absorbent socks
for oil clean-up, thereby eliminating a significant solid waste
stream.
• A state agency recently performed a waste assessment for
this plant.
• Corporate environmental audits are performed for this plant
periodically.
Pollution Prevention 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 pollution prevention that
the WMAC team recommended for the plant. The opportunity,
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the type of waste, the possible waste reduction and associated
savings, and the implementation cost along with the simple
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 financial savings of the opportunities
result from the need for less raw material and from reduced
present and future costs associated with waste management.
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 pollution preven-
tion opportunity independently and do not reflect duplication of
savings that would result when the opportunities are imple-
mented in a package.
This research brief summarizes a part of the work done under
Cooperative Agreement Mo. CR819557 by the University City
Science Center under the sponsorship of the U.S. Environmen-
tal Protection Agency. The EPA Project Officer was Emma
Lou George.
Table 1. Summary of Current Waste Generation
Waste Generated
Miscellaneous solid waste
Spent hydraulic oil
Spent honing oil and other
honing-related waste
Wastewater
Aluminum chips
Scrap aluminum parts
Mixed aluminum and iron chips
Scrap iron
Wastewater
Wastewater
Spent paint filters and floor coverings
Spent solvent
Evaporated solvent
Evaporated paint carrier solvent
Spent coolant
Wastewater
Filter cake
Dirty rags
Domestic water
Pallets and other waste wood
Cardboard
Source of Waste
Various plant operations
Machining operations
Machining operations
Washers (machining operations)
Machining operations
Rejected following leak testing
Machining operations
Machining operations
Chrome conversion
Washers (spray painting)
Spray paint booth
Cleaning of paint lines
Storage of cleaning solvent
Spray painting
Machining operations
Cleaning during final assembly
Onsite wastewater treatment facility
Various plant operations
Plant operations
Plant operations
Plant operations
Waste Management Method
Shipped off site to municipal landfill
Shipped offsite to be blended into fuel
Shipped off site to be blended into fuel
Treated in onsite wastewater treatment
facility; sewered
Sold to recycler
Sold to recycler
Shipped offsite for recycling (no revenue
received)
Shipped offsite for recycling (no revenue
received)
Treated in onsite wastewater treatment
facility; sewered
Treated in onsite wastewater treatment
facility; sewered
Compacted; shipped offsite for use in
fuel program
Shipped offsite to be blended into fuel
Evaporates to plant air
Evaporates to plant air
Shipped off site to be blended into fuel
Treated in onsite wastewater treatment
facility; sewered
Shipped offsite as hazardous waste
Shipped offsite to be cleaned; returned
for reuse
Sewered
Shipped offsite
Sold to recycler
Annual Quantity
Generated (Ib/yr)
2,300,000
6,860
24,400
879,220
540,370
103,580
352,780
32,350
14, 188,230
13,337,020
69,900
3,320
4,440
61,020
2,797,460
501,980
114,000
83,4 10 units
7,852,920
28,000
320,000
Annual Waste
Management Cost'
$7,950
1,070
24,080
1,820
-327,080
(net revenue received)
-62,690
(net revenue received)
2,550
1,350
97,680
28,340
83,080
4,710
450
1,500
63,460
270
19,540
n/a
4,300
1,350
-2,250
(net revenue received)
'Includes waste treatment, disposal, and handling costs, and applicable raw material costs.
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Ttblt 2, Summary ot Recommended Pollution Prevention Opportunities
Pollution Prevention Opportunity
Waste Reduced
Annual Waste Reduction
Quantity (Ib/yr) Per Cent
Net Annual Implementation Simple
Savings Cost Payback (yr)
Magnetically separate cast iron chips from
the mixed chip waste. Sell tha relatively
putt aluminum chips remaining to a metal
ncycler,
Intutt » closed-loop system tor recycling
of chrome-conversion rinse water and pro-
cess chemicals utiizing reverse osmosis.
Process chemicals lost in tha rinse water
will be removed tor reuse in tha process
tanks, The purified rinse water can be
reused,
Dust dmn holes in tho bottom ot the
metal chip coXoction bins in order to
a'fciv coolant to drain into collect-
ion pans Rocpndilion tha coolant
for rouse onsite,
Install an atmospheric evaporator to re-
move excess water from spent coolant
Reinstall missing or damaged shrouding
on tX metal'Wcrking machines to pre-
vent losses ot oooiant during metal
operations
Segregate aqueous washer Wastewater
Irom other plant Wastewater, treat
in an ultralOtration unit and reuse it ensile,
A smaS quantity ot oily waste will be gener-
ated as tlia system's membranes are back-
flushed and cleared. In addition, a small
quantity otwastewater will be generated
should the system water need to be purged.
Imtatta distillation unit to recover spent
cleaning solvent tor reuse onsite. In add-
ition, reduce evaporative losses of clean-
ing solvent through worker training and
equipment modirication. A smalt quantity
otstil bottoms will be generated it this
measure is implemented,
Mixed chip waste
Wastewater from chrome
conversion Filter
cake
Spent coolant
Spent coolant
Spent coolant
Wastewater from machining
Wastewater from spray-painting
Spent solvent
Evaporated solvent
11,205,000
91,200
805,440
2,774,150
402,750
879,220
13,337,020
3,320
2,220
79
80
29
99
14
100
100
100
50
$14B,6801 $105,640 0.7
$101,5901 84,440
52,750
50.2801
33,880
19,110
6.2601
0.9
2,260
29,800
9380
67,260
0.1
0.6
0.3
3.5
12,150
1.9
' Total annual savings have been reduced by the annual operating cost required for implementation of this measure.
United States
Environmental Protection Agency
National Risk Management Research Laboratory (G-72)
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/600/S-95/031
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