vvEPA
United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-94/011 September 1994
ENVIRONMENTAL
RESEARCH BRIEF
Waste Minimization Assessment for a Manufacturer of Aerial Lifts
Harry W. Edwards*, Michael F. Kostrzewa*,
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ment has been superseded by the Facility Pollution Prevention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
Colorado State University performed an assessment at a plant
that manufactures aerial manlifts, ventilating driers, and air
driers. The production of aerial manlifts requires sawing,
cutting, and machining of metal, zinc plating or painting, and
assembly. For the most part, only assembly operations are
required for production of the ventilating and air driers. The
team's report, detailing findings and recommendations, indi-
cated that the waste streams generated in the greatest quantity
are spent rinse waters from plating and paint preparation, and
the greatest cost savings could be achieved by replacing the
currently used parts washer with a system that uses a less
hazardous solvent.
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.
' Colorado State University, Department of Mechanical Engineering
" University City Science Center. Philadelphia, PA
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
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 Colorado State University's
(Fort Collins) 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 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
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.
iŁ3) Printed on Recycled Paper
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Methodology of Assessments
The waste minimization assessments require several site visits
to each client served. In general, the WMACs follow the
procedures outlined in the EPA Waste Minimization Opportu-
nity 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
This plant manufactures aerial manlifts (for use by electric and
telephone utilities), ventilating driers, and air driers. Approxi-
mately 1,500 aerial lifts and several thousand miscellaneous
items are manufactured annually during approximately 4,000
hr/yr of operation.
Manufacturing Process
The production of ventilating driers and air driers requires
mostly assembly operations, but aerial manlift production re-
quires a significant number of manufacturing processes.
Steel, in pipe, flat, and round stock form, is the raw material
used in the greatest quantity in producing the lifts. Smaller
quantities of aluminum, brass, copper, and bronze are also
used. The steel stock is cut to length to form blanks using a
power saw or a plasma cutting machine. Then the blanks are
punched to the proper length and shape using presses. Addi-
tional machining, including bending, welding, grinding, milling,
drilling, and lathe working, follows.
After machining, parts are either painted or zinc-plated. Parts
that are to be zinc-plated are processed through a series of
tanks containing solutions and rinses to clean, prepare, and
plate the parts. Plated parts are sent to the assembly area.
Many of the parts to be painted are processed in a five-stage
preparation and painting system. In the prep and paint line,
parts are mounted onto a conveyor system which carries them
through various operations including washing, phosphating,
rinsing, drying, spray painting, and baking. Other parts are
painted in a standard paint-booth type system or a stand-alone
paint/bake oven. In those systems, parts are placed inside the
booth or oven and are painted in batches. All parts that are
painted are baked in the bake oven.
A significant amount of welding is required in the production of
many of the products. Stock sheet metal is bent, punched, and
form welded to produce the main structural members of the
lifts. Sheet metal is welded to the structural components of the
lifts. The lift parts are painted in the stand-alone paint booth.
In the assembly area, painted, plated, and miscellaneous parts
are assembled into finished products. Hydraulic fluid is pumped
into reservoirs. The completed lifts are inspected, hydraulically
tested, stored, and then shipped to customers.
An abbreviated process flow diagram for the manufacture of
aerial lifts is shown in figure 1.
Existing Waste Management Practices
This plant already has implemented the following techniques to
manage and minimize its wastes.
Spray-mist lubricant is used on the saw in order to avoid
generating a hazardous waste stream.
Scrap metal from the machining processes is recycled.
Spent solvent generated in the painting area is recovered
through distillation and reused.
High-volume, low-pressure paint spray guns are used in the
painting area thereby reducing overspray, paint usage, and
solvent air emissions.
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 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 simple payback time are given in the table. The
quantities of waste currently generated by the plant and pos-
sible waste reduction depend on the production level of the
plant. All values should be considered in that context.
ft 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 may result
when the opportunities are implemented in a package.
Additional Recommendations
In addition to the opportunities recommended and analyzed by
the WMAC team, one additional measure was considered.
This measure was not analyzed completely because of a
projected lengthy payback. Since this. approach to waste
reduction may, however, increase in attractiveness with chang-
ing conditions in the plant, it was brought to the plant's atten-
tion for future consideration.
Reduce rinse water consumption and drag-out from the zinc-
plating bath by installing counterflow rinsing and an atmo-
spheric evaporator to evaporate excess water from the
rinses.
This research brief summarizes a part of the work done under
Cooperative Agreement No. CR-819557 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.
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Steel
Waste cooling
water shipped
oflsite
Spent cutting
KuM shipped
offslte
Waste liquids
pro-treated
onslte and
sewered
Paint
preparation
Wastes shipped
off site for
Incineration
Waste oil shipped
off site for
blending as fuel
Completed lifts shipped
to customers
Figure 1. Abbreviated Process Flow Diagram for Lift Manufacturing.
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Table 1. Summary of Currant Waste Generation
Waste Stream Generated
Cooling fluid
Cutting fluid
Wastewater treatment sludge
Rinse water
Waste alkaline solutions
Waste acidic solutions
Alkaline cleaner
Overflow rinse water
Phosphating solution
Rinse water
Body wash
Paint solvent still bottoms
Evaporated paint solvent
Expired paint
Paint cleaning solvent
Waste oil
Absorbent clay
Cardboard
Nonrsusabls pallets
Pefroleum naphtha
Source of Waste
Plasma cutting of metal
Machining operations
Treatment of waste liquids from
plating and paint preparation
Metal plating
Metal plating
Metal plating
Preparation of metal for painting
Preparation of metal tor painting
Preparation of metal for painting
Preparation of metal tor painting
Cleaning of product bodies
Onsite recovery of spent paint
solvent used for paint gun cleaning
Cleaning of paint guns
Panting operations
Cleaning of paint guns
Assembly of product
Cleanup of spills during assembly
Various sources
Various sources
Parts washers
Waste Management Method
Shipped offsito; solidified and buried
Shipped offsite; solidified and buried
Shipped offsite; buried
Treated onsite; sewered
Treated onsite; sewered
Treated onsite; sewered
Treated onstta; sewered
Treated onsrte, sewered
Treated onsite; sewered
Treated onsite; sewered
Treated onsite; sewered
Shipped offsite; incinerated
Evaporates to plant air
Shipped offsite; incinerated
Shipped offsite: recycled or incinerated
Shipped oft site, blended into boiler fuel
Shipped to municipal landfill
Shipped to municipal landfill
Shipped to municipal landfill
Shipped offsite; recycled or incinerated
Annual Quantity
Generated (Ib)
21,870
36,440
41,690
6,122,550
29,990
59,980
8,330
26,660
8,330
992,840
612,260
2,020
2,270
10,120
410
3,670
5,640
91,160
72,000
6,730
Annual Waste
Management Cost'
$5,680
6,530
6,890
1,980
10
20
0
0
0
320
200
8,910
1,570
19,650
1,310
20
570
6,990
3,880
8,450
Includes waste treatment, disposal, and handling coses, and applicable raw material costs.
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Table 2. Summary of Recommended Waste Minimization Opportunities
Annual Waste Reduction
Minimization Opportunity
Replace the currently used rental parts
washer with a cleaning system that uses
a less hazardous solvent.
Institute a formal cutting fluid manage-
ment program.
Engage a recycling firm to collect the
pallets that currently are shipped to a landfill.
Install an enclosed spray gun washer system
to reduce evaporation of cleaning solvent.
Replace clay absorbent used for cleanup
with absorbent pads and a wringer.
Filter and reuse the plasma cutter cooling fluid.
Waste Stream Reduced
Petroleum naphtha
Cutting fluid
Wooden pallets
Evaporated paint solvent
Absorbent clay
Cooling fluid
Quantity (Ib)
6,730'
31,700
0
1,700
5,640 3
11,000
Per cent
100
87
0
75
100
50
Net Annual
Savings
$6,250 2
4,800*
3,580
1,180
540
460 2
Implementation
Cost
$8,840
8,000
0
2,000
700
1,050
Simple
Payback (yr)
1.4
1.7
0
1.7
1.3
2.3
' A total of 1,000 Ib/yr of combined solvent and filter waste will be generated.
2 Total possible savings have been reduced by a required annual operating cost.
3 740 Ib/yr of waste oil and used pads will be generated.
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United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
EPA/600/S-94/011
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
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