xvEPA
                         United States
                         Environmental Protection
                         Agency
                                    National Risk Management
                                    Research Laboratory
                                    Cincinnati, OH 45268
                         Research and Development
                                    EPA/600/S-95/015   August 1995
ENVIRONMENTAL
RESEARCH    BRIEF
               Pollution Prevention Assessment for a Manufacturer of
                             Combustion Engine Piston Rings

                              Richard J. Jendrucko*, Todd M. Thomas*, 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ment has been superseded by the Facility Pollution Prevention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 piston rings.  Steel and iron rings are
machined, chrome-plated or coated, machined again, cleaned,
and shipped to customers. The assessment team's report,
detailing findings  and recommendations, indicated that waste-
water and wastewater treatment sludge are the waste streams
generated in greatest quantity and that the greatest cost sav-
ings could be achieved by modifying the method of masking
the rings prior to chrome plating.

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 (Knoxville) 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.


                         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

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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
This  plant produces  piston  rings that are  used  in diesel  en-
gines.  Almost  four million  piston rings  are produced by  the
plant each year during 6,000 hr of production.


Manufacturing Process
Each of the major processes used  by this plant—piston ring
machining and  hard chrome electroplating—is described here
in  detail.


Piston Ring Machining
The necessary  raw materials, steel and ductile iron rings,  are
received  and stored until needed in  production.   To begin
production,  approximately 100 rings  are placed on a steel  rod
for ease  of processing.  Next, the rings  enter a sequential
machining line where they are blank-turned, bored, slot-milled,
and finish-turned.  After these initial machining operations,  the
rings are separated  according to their final use as  bottom-
rings, top-rings,  or intermediate-rings, and further processed as
required.

Following these machining operations, approximately 95% of
the rings are prepared for chrome plating.  First, those rings
are degreased  to remove protective oils and machining resi-
due.  Then the  inside ring surfaces are masked using  lacquer-
based paint  film to prevent chrome plating  on those surfaces.
After paint masking, the outer ring surfaces are grit blasted to
enhance  chrome  adhesion during plating.  The final  step is
removal of grit blast residue using a high-pressure spray-wash.
The rings are then transported to the chrome-plating process.

The other 5% of the rings are prepared to receive a  magne-
sium phosphate coating in  a  hot water wash for removal of
remaining machining debris and protective  oils.  The rings  are
then  dipped into the magnesium  phosphate tank.  After  the
coating has  dried the rings are dipped in  rinse tanks for re-
moval of residual coating solution.  Depending  on their final
use, the coated rings undergo additional  machining and grind-
ing.   The  rings are then cleaned  in  solvent,  marked with
identification numbers, cleaned again, dipped in a rust preven-
tative, and shipped to customers.


Chrome Electroplating
The plant's plating line operation is semi-automated.  Use of a
computer reduces human error and standardizes plating  op-
erations.

A  heated sulfuric  acid etch is the  first tank in the plating line.
The etch is used to enhance the ring's surface to  facilitate
chrome adhesion.  Following etching, the rings are rinsed and
placed in one of four heated chromic acid plating tanks.  Resi-
dence  time  varies  according to the type  and thickness  of
chrome deposit required.

Next, the rings are rinsed in a cold water rinse tank and then
with a  high-pressure water spray. Masking  paint on the  inside
ring surfaces is removed  by dipping the rings into a series of
tanks  containing paint stripping agents and water rinses. The
rings are then dipped in a tank containing  rust inhibitor solu-
tion.   Inspection of the rings for proper chrome application is
done  next.  Unacceptable rings are  stripped of  chrome and
replated.

After chrome plating the  rings are machined and ground as
needed.  The rings are then cleaned in solvent,  marked with
identification numbers, cleaned again, dipped in a rust preven-
tative, and shipped to customers.

An abbreviated  process flow diagram for piston ring manufac-
ture is  shown in Figure!


Existing Waste Management Practices
This plant already has implemented the following techniques to
manage and minimize its wastes.

  •  Personnel from the plant's  parent corporation  conduct a
    waste assessment each year to specify waste reduction
    measures for the facility.

  •  A  local  university performed a waste  audit for the plant
    several years ago.

  •  Waste cardboard is baled  and sold.

  •  Sludge from the plant's general wastewater treatment sys-
    tem is shipped to a facility for fuels blending.

  •  Sludge from the plant's chrome wastewater treatment sys-
    tem is shipped to an outside firm for metals extraction.

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 treatment and disposal 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, 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 waste treatment and  disposal.  Other savings not quantifi-
able  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

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implementing each opportunity independently and do not re-
flect duplication of savings that may result when the pollution
prevention 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 one or more of these approaches to waste
reduction may, however, increase in attractiveness with chang-
ing  conditions  in the plant, they were brought to the plant's
attention for future consideration.
  •  Install covers on all heated tanks to minimize evaporative
    water losses and to conserve energy.

  •  Use aqueous cleaners instead of solvents forwashing piston
    rings.

  •  Separate nonhazardous from hazardous wastewaterstreams
    to reduce the volume of sludge from treatment that must be
    considered hazardous and its associated costs.
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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                            Precast Steel and
                               Iron Rings
                                  I
                          Machining Operations
                       Blank Turning, Boring, Slot
                          Milling, Finish Turning
                                                                                 Heat Shape
                                                                                    Oven
                                                                                  Cam and
                                                                                Finish Turning
                                                                           Vapor
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              Plating
Etching
Grit Blast
Cleaning
  Paint
Masking
                                                           Machining
                                                            Magnesium
                                                            Phosphate
                                                              Dipping
                                                            Cleaning
                                                           Packaging
                                                      Piston Rings Shipped
                                                          to Customer
Figure 1. Abbreviated process flow diagram for piston ring manufacture.

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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-95/015

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