©EPA
                               United States
                               Environmental Protection
                               Agency	
                                 Risk Reduction
                                 Engineering Laboratory
                                 Cincinnati, OH 45268
                               Research and Development
                                 EPA/600/M-91/044 Oct. 1991
ENVIRONMENTAL
RESEARCH   BRIEF
            Waste Minimization Assessment for a Manufacturer of
                    Refurbished Railcar Bearing Assemblies

                            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 waste but who lack
 the expertise to do so. Waste Minimization Assessment Cen-
 ters (WMACs) were established at selected universities and
 procedures were adapted from the EPA Waste Minimization
 Opportunity Assessment Manual (EPA/625/7-88/003 July
 1988).  The WMAC team at the University of Tennessee
 performed an assessment at  a plant that rebuilds railcar
 bearing assemblies — approximately 163,200 bearing com-
 ponents per year. Bearings are disassembled, washed, then
 inspected. "Premium" bearings, those still within specifica-
 tions, are reassembled with new grease and bearing seals,
 packaged, and shipped. Nonpremium bearings are buffed,'
 rinsed in hot water, and then chrome plated to build up the
 bearing surfaces. After chroming, the parts are rinsed, baked,
 and allowed to air cool. Cooled bearings are reassembled with
 new grease and seals, then packaged and shipped. The
 team's report, detailing findings and recommendations, indi-
 cated that the majority of waste was generated during the
 railcar bearing cleaning operation and that the greatest sav-
 ings could be obtained by instigating onsfte wastewater treat-
 ment and recirculating recovered water to reduce (90%) water
consumption in the railcar bearing cleaning operation.
•University City Science Center, Philadelphia, PA 19104.
               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.

               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 is to reduce or eliminate the waste af 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 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 atthe 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 waste generation.

              The waste minimization assessments are done for small- and
              medium-size manufacturers at no  out-of-pocket cost to the
              client. Toqualifyforthe assessment, each client must fall within
              Standard Industrial Classification Code 20-39, have gross

                                   ^£9 Printed on Recycled Paper

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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 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
/lss0ssmenfManua/(EPA/625/7-88/003.July1988).TheWMAC
staff locates the sources of waste in the plant and identifies the
current disposal or treatment methods and their associated
cosis.Theythen identify and analyze a variety of ways to reduce
or eliminate the waste. Specific measures to achieve that goal
are recommended and the essential supporting technological
and economic information is developed. Finally, 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  refurbishes railcar bearing assemblies for outside
customers. Its 120 employees produce approximately 163,000
bearing assemblies annually.

Manufacturing Processes
This plant  rebuilds railcar bearing  assemblies. Raw materials
Include bearing lubricant (grease), new bearing seals, chrome
plating constituents (chromic acid and sulfuric acid), alkaline
detergent,  and rust preventative.

The following steps are involved in  refurbishing the railcar
bearings:

   •  Bearings, which are shipped to the plant from outside
     customers, are disassembled and parts are separated.
     Lubricant is removed by manually wiping off the bearing
     parts, placing the parts in  a centrifugation device, and
     wiping off any residual lubricant.  Discarded grease is dis-
     posed of offslte as npnhazardous waste. Spent seals are
     disposed of in municipal waste.

   •  Bearing parts are then  washed  in an alkaline-detergent
     solution and rinsed. Contaminated water is shipped offsite
     for disposal as a nonhazardous waste. Next, the bearings
     are inspected to ensure proper surface thickness along the
     cone surface. Those bearings that meet specifications and
     are characterized as "premium" are reassembled with new
     grease and  bearing seals while the bearings that are
     identified as "nonpremium" are transferred to the chrome
     shop for electroplating buildup of the inside surfaces of the
     bearings. In the chrome shop, the bearing surfaces are
     buffed then rinsed in hot water. The parts are then racked
     and dipped in the chromic acid plating tanks. After chrom-
     ing, the parts are rinsed in hot and then cold water. Chromic
     acid sludge that results from chrome shop operations is
     shipped offs'rte as hazardous waste. Parts are then baked
    in a dry-off oven, cooled, and reassembled with new grease
    and seals.

Existing Waste Management Practices
  • Trivalent chrome that is produced during chroming opera-
    tions is regenerated into hexavalent chrome for reuse,
    thereby greatly reducing the amount of waste generated
    and the cost of raw materials and waste removal.

  • The plant has sealed all but the sanitary sewer drains and
    ships offsite all nonhazardous waste water generated from
    bearing cleaning operations to avoid  interaction with the
    liquid municipal waste treatment agency (POTW).

  • Plant personnel reduce residual drag-out from the chrom-
    ing operations  by individually rinsing  each part and rack
    above the chrome and  rinse tanks, thus reducing the
    concentrations of plating metals in the chromic acid sludge
    that is shipped offsite as a hazardous waste. This additional
    rinsing operation also supplies make-up water to the chrome
    plating baths to compensate for evaporative losses.

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 forthe 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 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 minimization
opportunity, in most cases, results 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 should also be noted that the savings given for each
opportunity reflect the savings achievable when implementing
each waste minimization opportunity independently and do not
reflect duplication of savings that would result when the oppor-
tunities are implemented in a package.

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 Emma Lou
George.

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 Table 1. Summary of Current Waste Generation
 Waste Generated
    Source of Waste
                      Annual Quantity
                        Generated
                                  Annual Waste
                                 Management Cost
 Spent grease
Spent bearing seals
Contaminated wash and
rinse water
Chromic acid sludge
    Cleaning of railcar bearings. Grease that is             2,750 gal
    removed from the bearing parts is disposed of
    offsite.

    Disassembly of railcar bearings. Spent bearing        326,400 units
    ' seals are disposed of in municipal trash.

    Cleaning of railcar bearings. The wash and            249,975 gal
    rinse water used in cleaning the bearings is
    shipped offsite as nonhazardous waste.

    Chroming processes. Chrome sludge that               660 gal
    results from the rinsing and plating operations in
    chrome shop is shipped offsite as hazardous
    waste.
                                                    $13,200



                                                       3,150


                                                     50,050



                                                     33,530
Table 2. Summary of Recommended Waste Minimization Opportunities


...           _  _,   J                               Annual Waste Reduction         Net         Implementation    Payback
Waste Stream Reduced    Minimization Opportunity       Quantity        Percent    Annual Savings        Cost          Years
Contaminated wash
and rinse water
Chromic acid sludge
Install a closed wastewater    244,480 gal
treatment system and
redrculate tine water for
bearing cleaning
Install a chromic acid
recovery system. It is
estimated that 90% of the
chromic acid can be purified
and reused in the chroming
165 gal
               98
25
           $32,170
                                                                                 15,120
                                          $41,880
                            42.700
-1.3
2.8
                                                                              •trV.S. GOVERNMENT PRINTING OFFICE: 1991 - S48-028/4007«

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United States                           Center for Environmental Research          BULK RATE
Environmental Protection                 Information                              POSTAGE & FEES PAID
Agency                                Cincinnati OH 45268                      EPA PERMIT NO. G-35


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EPA/600/M-91/044

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