United States
Environmental Protection
Agency
National Risk Management
Research Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S-95/022 August 1995
ENVIRONMENTAL
RESEARCH BRIEF
Pollution Prevention Assessment for a Manufacturer
of Rebuilt Industrial Crankshafts
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ment has been superseded by the Facility Pollution Prevention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 refurbishes large industrial crankshafts. Worn crankshafts
received by the plant are cleaned and stripped of chromium.
The crankshafts are inspected for defects, repaired as re-
quired, annealed, and straightened. Bearing surfaces are rough
ground, crankshaft journal surfaces are shot-peened, and the
crankshafts are cleaned. Then the crankshaft surfaces and
selected bearing surfaces are electrochemically plated with
chromium. Next, the crankshafts are baked, shot-peened again,
and fine ground to final specifications. The team's report,
detailing findings and recommendations, indicated that the waste
stream generated in the greatest quantity is spent cutting fluid
from the grinding of crankshafts and that significant cost sav-
ings could be achieved by implementing a formal cutting fluid
management program.
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.
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
National Risk Management Research 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
considerable direct experience with process operations in manu-
facturing 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.
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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
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
This plant rebuilds large industrial crankshafts that are distrib-
uted regionally. Over 4,000 jobs are completed each year by
the plant during 2,210 hr/yr of operation.
Manufacturing Process
Worn crankshafts received by the plant are cleaned and
degreased in a heated caustic solution. Chromium plating is
then electrolytically stripped from the crankshafts in a caustic
solution. The chromium may also be removed mechanically
using large grinders.
Next, the crankshafts are inspected for cracks and flaws using
two different methods. One method entails applying a penetrat-
ing fluorescent dye solution and a visual inspection using a
UV-light. The second method involves the use of a solvent
containing fine, magnetic particles and application of a mag-
netic field which is distorted by any defects present.
Defects are repaired and worn metal is built up using arc
welding. Stresses are relieved in an annealing oven and a
hydraulic press is used to straighten the crankshafts as needed.
The bearing surfaces are then rough ground to desired factory
specifications.
Following grinding, the crankshafts are prepared for chromium
plating. The crankshaft journal surfaces are shot-peened to
relieve surface stresses, and the crankshafts are cleaned with
air-blown abrasive particles. Keyways are plugged with lead to
prevent plating of their surfaces and masking is applied as
needed to prevent plating of other surfaces. The crankshaft
surfaces and selected bearing surfaces are electrochemically
plated with chromium using heated chromic acid plating baths.
After plating, the crankshafts are baked to remove hydrogen
absorbed during plating, shot-peened again, and fine ground to
final specifications. A final magnetic particle inspection follows
grinding. The shafts are then dynamically balanced, polished,
and packaged and shipped to customers or added to inventory.
An abbreviated process flow diagram for the rebuilding of
crankshafts is shown in Figure 1.
Existing Waste Management Practices
This plant already has implemented the following techniques to
manage and minimize its wastes.
• All rinsing of crankshafts is done over process solution tanks
to reduce effluent to the sewer.
• Electrodialysis is used to maintain the chromium plating
baths, thereby extending bath life and reducing the need for
replacing the plating solutions.
• Lead anodes are melted and repoured to reduce the genera-
tion of waste lead.
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 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,
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 economic savings of the opportuni-
ties, in most cases, result from the reduction in raw material
and from reduced present and future costs associated 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 em-
ployee health. It also should be noted that the savings given for
each opportunity reflect that pollution prevention opportunity
only 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, several other measures were considered.
These measures were not analyzed completely because of
insufficient data, implementation difficulty, or a projected lengthy
payback. Since these approaches to pollution prevention may,
however, increase in attractiveness with changing conditions in
the plant, they were brought to the plant's attention for future
consideration.
• Replace the rented parts washers that use petroleum naph-
tha with alternative cleaning systems using a less hazardous
solvent.
• Develop a formal management plan for the maintenance of
the chromium plating solutions to increase bath life and
reduce waste generation. Special emphasis should be placed
on the maintenance and performance of the electrodialysis
equipment. Several measures are in place to maintain the
solutions, but procedures should be formalized.
• Investigate possible alternatives to the landfilling of chro-
mium-contaminated soil and evaporatorsludge stored onsite
pending identification of a suitable disposal method. Further
analysis requires sampling and quantitative analysis of the
chromium bearing wastes to determine the suitability of
recycling. Such procedures are beyond the scope of the
WMAC program.
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. Environ-
mental Protection Agency. The EPA Project Officer was Emma
Lou George.
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Worn Crankshafts
Cleaning
Chemical
Stripping
Inspection
Refurbished
Crankshafts
Welding
Abrasive
Cleaning
Chromium
Plating
Shot-Peening
Shot-Peening
Pre-Grinding
Final
Grinding
Annealing
Packaging
Polishing
Balancing
Figure 1. Process flow diagram for industrial crankshaft refurbishing.
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Table 1. Summary of Current Waste Generation
Waste Stream Generated
Source of Waste
Waste Management Method
Annual Quantity Annual Waste
Generated (Ib/yr) Management Cost
Waste caustic cleaning solution
Waste stripping solution
Evaporated penetrant/dye
Spent parts cleaning solvent
Initial cleaning of crankshafts
Chromium stripping of crankshafts
Inspection of crankshafts
Parts washer
Stored onsite pending determination of an
appropriate waste management method1
Stored onsite pending determination of a
appropriate waste management method1
Evaporated to plant air
Removed by supplier; distilled offsite for
41,800
$2,1302
30,000 0
1,110 2802
Spent cutting fluid
Grinding sludge
Waste hydraulic oil
Evaporator sludge
Waste stripping solution
Lead slag
Waste caustic cleaning solution
Grinding of crankshafts
Grinding of crankshafts
Routine maintenance of grinders
Previous waste management
method for caustic wastes
Rework of plated crankshafts
Preparation of anodes for plating
Cleaning of anodes
reuse or incinerated
Filtered from grinding sludge; drained
through sand trap; sewered as industrial
wastewater
Shipped offsite for stabilization and burial
at a hazardous waste disposal facility
Removed by oil recycler; blended to produce
industrial boiler fuel
Stored onsite pending determination of an
appropriate waste management method
Stored onsite pending determination of an
appropriate waste management method1
Accumulated onsite
Stored onsite pending determination of an
appropriate waste management method1
1,810
178,700
25,400
2,350
13,600
10,000
9,160
1,500
1,250
6,560?
8,300
60
0
0
0
2,500?
Prior to the assessment, the caustic wasfes were combined and placed in an evaporator. The evaporator was used to reduce the volume and weight of waste prior to disposal.
At the time of the assessment these wastes were being stored onsite. Filtration and the use of a sludge dryer were being considered as alternative waste management methods.
Includes applicable lost raw material value.
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Table 2. Summary of Recommended Pollution Prevention Opportunities
Annual Waste Reduction
Pollution Prevention Opportunity
Waste Stream Reduced Quantity (Ib/yr)
Per Cent
Net Annual
Savings
Implementation
Cost
Simple
Payback (yr)
Install a high pressure washer and filtration
system for the caustic solution used to
provide the initial crankshaft cleaning.
It is proposed that a small spray washer
be used to clean the crankshafts over the
caustic tank and a filtration system be
used to remove particulate matter from the
solution, thereby extending the life of the
solution.
Implement a formal cutting fluid manage-
ment program for the grinders that use
aqueous cutting fluids. The program
should involve daily and regular main-
tenance, periodic cleaning, data gath-
ering and tracking, and filtering of
particulate matter. A reduced volume
of waste grinding fluid will be generated
as a result of the program.
Filter the solvent used for magnetic in-
spection of the crankshafts in order to
increase its life. The solvent would be
pumped from the existing tank, filtered,
and returned.
Waste caustic cleaning
solution
26,500
63
$4,450
$910
0.2
Spent cutting fluid
119,000
67
3,680
4,360
1.2
Evaporated penetrant/dye
550
50
270
110
0.4
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United States
Environmental Protection Agency
National Risk Management Research Laoratory (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-95/022
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