United States
 Environmental Protection
 Agency
 Risk Reduction
 Engineering Laboratory
 Cincinnati, OH 45268
 Research and Development
 EPA/600/SR-92/188
October 1992
 Project  Summary

 An  Automated  Aqueous  Rotary
 Washer  for  the Metal  Finishing
 Industry
Arun R. Gavaskar, Robert F. Olfenbuttel, Jody A. Jones, and Tad C. Fox
  Product quality, waste reduction, and
economic issues involved in the use of an
automated aqueous rotary washer in the
metal finishing industry were evaluated in
this study. The automated washer can be
used for most metal parts that would or-
dinarily be cleaned by vapor degreasing,
hand-aqueous washing, or alkaline tum-
bling. The automated  washer had  good
potential to reduce waste, was economi-
cally viable, produced good product qual-
ity, and also avoided the vapor degreaser's
use of perch loroethylene. When compared
with hand-aqueous washing  and alkaline
tumbling, the automated washer used less
chemicals. The payback period was about
7 years.
  This Project Summary was developed
by  EPA's Risk  Reduction  Engineering
Laboratory, Cincinnati, OH, to announce
key findings of the research project that is
fully documented in a separate report of
the same title (see Project Report ordering
information at back).

Introduction
  The Pollution Prevention Act of 1990 es-
tablishes  pollution prevention as a "national
objective." The Act notes that there are sig-
nificant opportunities for industry to reduce or
prevent pollution at the source through cost-
effective changes in  production,  operation,
and raw materials use. Source reduction is
fundamentally different from and more  desir-
able than waste management  and pollution
control. Source reduction is defined in the law
to mean any practice that reduces the amount
of a hazardous substance, pollutant, or con-
taminant  entering  a wastestream or other-
wise released into the environment before
recycling, treatment, or disposal.
  The objective of the U.S. Environmental
Protection Agency's (EPA) Waste Reduction
Innovative Technology Evaluation (WRITE)
Program is to evaluate, in a typical workplace
environment, examples of prototype or com-
mercial technologies that have potential for
pollution prevention. This particular evaluation
was a cooperative effort among EPA's Risk
Reduction Engineering Laboratory, Connecti-
cut Hazardous Waste Management Service,
and Quality  Rolling and Deburring (QRD)
Company. The study evaluated an automated
aqueous washer for cleaning small metal parts
in the metal finishing industry. The goal of the
study was to provide information to  potential
users of this technology. The objectives were
to evaluate (1) the product  quality  resulting
from new automated washer versus each of
three older processes, (2) the pollution pre-
vention potential of the new technology, and
(3) the economic attributes of the new tech-
nology.
  One of the major steps in metal finishing is
cleaning metal parts to remove oil and grease,
dirt, and metal chips.  Cleaning may involve
washing with a detergent or  degreasing with
a solvent. Before installing  the automated
aqueous washer, QRD (the site for this study)
routed metal cleaning jobs  through one of
three cleaning processes: vapor degreasing,
alkaline tumbling, or hand-aqueous washing.
The cleaning process chosen is based on the
type of metal part and the suitability of the
cleaning process.

Product Quality Evaluation
  The product quality evaluation was based
on (a) an examination of the cleaned  metal
                                                     Printed on Recycled Paper

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 parts from some of QRD's normally sched-
 uled cleaning  jobs, (b) an  examination  of
 cleaned test panels inserted along with the
 metal parts in the cleaning jobs,  and (c) a
 water break test conducted on  the cleaned
 test panels from  the  alkaline tumbler and
 automated washer.
   Three cleaning jobs (each containing sev-
 eral thousand small metal parts) were selected
 from the several that QRD  receives  every
 day. Job A consisted of steel  caplets that
 were suitable for cleaning  on the  vapor de-
 greaser. Job B consisted of aluminum  rivets
 that were suitable for cleaning on  the hand-
 aqueous  washer.  Job C consisted of steel
 cylinders  that were suitable for  cleaning on
 the alkaline tumbler. Job C involved cleaning
 as well as electroplating (nickel plating).
   Each job was split  into  halves. Half was
 cleaned by the  automated washer, and the
 other half was cleaned by one  of the  older
 processes. This experimental design provided
 a one-to-one comparison between the  auto-
 mated  washer and each of the three  older
 processes.
   After each cleaning  run, a predetermined
 number (150) of randomly selected, cleaned
 parts were examined for product quality. Visual
 examination revealed no noticeable contami-
 nation on any of the parts  for all three jobs
 nor on  the cleaned test panels. The water-
 break test indicated that the parts destined for
 electroplating  had  been cleaned  well. The
 results of these examinations, therefore, show
 that the three old processes and  the auto-
 mated  process resulted in  good product
 quality,  although certain delicate  parts still
 need vapor degreasing and some  parts that
 are  diffucult to  clean  need  hand-aqueous
 washing.

 Pollution Prevention Potential
   Pollution prevention was measured in terms
 of waste  volume  reduction (Table 1) and
 pollutant reduction (Table 2). The total waste
 volume generated by the automated washer
 is much bwer than either the alkaline tumbler
 or hand-aqueous washer. This indicates that
 the automated washer needs fewer resources
 to process wastes downstream.
   Note  that the processing energy require-
 ment of the automated washer is  higher than
 the energy requirement of any of the three
 older processes. The moderately higher pro-
 cessing energy requirement of the automated
 washer should, however, be weighed against
 the potentially higher energy requirements of
 the older processes in  such other  areas as
 waste treatment. Secondary pollution resulting
 from energy consumption was not  a part of
 this evaluation.
  Although the waste volume generated by
the vapor degreaser is bwer than that of the
 automated washer, it is much more hazardous.
  Table 1.  Comparison of Annual Waste Volume from the Cleaning Processes
  Wastestrearn

  Vapor Degreasing a
   Wastewater in separator
   Still bottom sludge
   Air emissions

 Alkaline Tumbling fr
   Wastewater
 Hand-Aqueous Washingc
   Wastewater
                          Volume Generated
                              Per Year
                      Wastestream
                   Volume Generated
                       Per Year
                         (gal)
       200
      1,440
see Table 2
                             1,010,880
                               296,400
Automated Washing'
 Wastewater             143,000
 Oily Liquid                 962
                     Automated Washing"
                       Wastewater             85,800
                       Oily Liquid                 577

                     Automated Washingc
                       Wastewater             57,200
                       Oily Liquid                 385
 3 Based on 5,200 bbl/yr run on automated washer instead of vapor degreaser.
 " Based on 3.120 bbl/yr run on automated washer instead of alkaline tumbler.
 c Based on 2 080 bbl/yr run on automated washer instead of hand-aqueous washer.
 Perchloroethylene, used in vapor degreasing,
 is a  hazardous chlorinated solvent  on the
 EPA's Toxics Release Inventory.  Perchloro-
 ethylene is also one of the 17 prbrity pollutants
 targeted in the EPA Administrator's 33/50
 Program for 50% reduction in releases  by
 1995. It is used in degreasing because it has
 a high boiling point and is therefore suitable
 for removing high melt waxes and for clean-
 ing light-gauge metal parts.
   Perchloroethylene can be a  health prob-
 lem,  with inhalation  and skin  as the main
 entry routes. Occupational Safety and Health
 Administration exposure limits  are  100 ppm
 (8-hr  time weighted analysis), 200 ppm (ac-
 ceptable ceiling concentration),  and 300 ppm
 (acceptable maximum peak). Vapor inhalation
 can cause eye irritation (at 400 ppm), respi-
 ratory irritation  (at  600 ppm), or anesthesia
 (200  ppm for  8 hr) according to the  Metals
                  Finishing Guidebook and  Directory (1988).
                  Prolonged or repeated skin exposure  can
                  cause dermatitis.
                    Spent  perchloroethylene is  listed  under
                  Resource  Conservation and Recovery  Act
                  (RCRA) as a hazardous waste (EPA hazard-
                  ous waste number F001).  Other commonly
                  used  degreasing solvents are  methylene
                  chloride, 1,1,1-trichloroethane, and trichforo-
                  ethylene, all of which are hazardous. The use
                  of the automated washer reduces the use of
                  these solvents.
                    The automated  washer generates  a
                  wastewater containing surfactants, which are
                  a much lower hazard both  in terms of occu-
                  pational safety and the environment. Surfac-
                  tants are not RCRA hazardous wastes. They
                  can, however, cause environmental problems.
                  Phosphate detergents are the main cause of
                  increased  algal growth (eutrophication) in
 Table 2.  Pollutants Generated by Cleaning Processes
Pollutant

Vapor Degreasing 3
 Perchloroethylene
 Perchloroethylene
 Perchloroe thylene

Alkaline Tumbling"
 Anionic surfactant
Hand-Aqueous Washing
 Non-ionic surfactant
Medium
Sludge
Water
Air
Amount
Generated
Per Year
(Ib)
45
negligible
6,145
Pollutant
Automated Washing *
Anionic surfactant
Non-ionic surfactant
Amount
Generated
Per Year
Medium (Ib)
Water 2
Water 22
                       Water
                       Water
                                   43
                                  105
                  Automated Washing"
                   Anionic surfactant       Water       1
                   Non-ionic surfactant     Water      13

                  Automated Washingc
                   Anionic surfactant       Water       1
                   Non-ionic surfactant     Water       9
3 Based on 5,200 bbl/yr run on automated washer instead of vapor degreaser.
" Based on 3,120 bbl/yr run on automated washer instead of alkaline tumbler.
c Based on 2,080 bbl/yr run on automated washer instead of hand-aqueous washer.

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 face waters where they are discharged, cause
 waters to have an obnoxious odor and taste,
 have a detrimental effect on fish because of
 the high biochemical oxygen demand (BOD)
 they create, and become a nuisance for rec-
 reational activities. Hence, nonphosphate de-
 tergents are increasingly being used.
   Different surfactants vary widely in terms of
 aquatic toxicity and ease of biodegradation.
 Surfactants accumulate within aquatic organ-
 isms and impair their functions. When com-
 pared with alkaline tumbling or hand-aqueous
 washing,  the  automated washer generates
 bwer amounts of these surfactant wastes.
   The results of the study indicate that mea-
 surable pollution prevention accrues from us-
 ing the automated washer  instead  of any of
 the three older cleaning processes.

 Economic Evaluation
   The economic evaluation of automated
 washing was  based on (a) major  operating
 costs  of the  automated  washer compared
 with each of  the three older  cleaning pro-
 cesses and (b) an estimation of the return on
 investment (ROI) and payback period for the
 automated washer. The number of  barrels of
 metal  parts that were used in this estimate
 was based on the annual number of barrels
 processed through  the automated washer.
 This total was divided into three parts based
 on the percentages of the  parts run on the
 automated washer that could have gone to
 each of  the three older  processes. Of the
 10,400 barrels run on the automated washer
 per  year, 5,200 would have gone  to vapor
 degreasing, 3,120 to alkaline tumbling, and
 2,080 to hand-aqueous washing.
   Tables 3, 4, and 5 compare the operating
 costs of the  older cleaning processes and
 those of the automated washer. The results
 of the economic calculations  showed  that,
 based on a capital requirement of $207,260,
 the payback period for QRD (where the ROI
 exceeds 15%) was about  7 yr.  Reducing the
 amount of solvent used can also reduce pos-
 sible liability resulting from  health claims or
 pollution  fines,  but these savings were  not
 quantified by this study and were not in the
 economic calculations.

 Discussion and Conclusions
   The automated aqueous washer evaluated
 in this study  is an  example of  a  pollution
 prevention technology for the metal finishing
 industry.  Source  reduction  is  achieved by
 substituting an aqueous cleaning process for
 a solvent cleaning process  (vapor degreasing).
 Source reduction is also achieved by reducing
the amount of raw  materials  (cleaners or
detergents) and process water used (alkaline
tumbling and hand-aqueous washing). Auto-
 mated washing  reduces  the volume of
wastewater that has to be treated (either on-
srte or at the publicly owned treatment works)
 Table 3. Operating Costs of Vapor Degreasing and Automated Washing
 Cost Element
                            Vapor Degreasing Cost •
                                   ($/Yr)
                               Automated Washing Cost'
                                        ($/Yr)
Labor(base rate)
Energy
Chemicals
Water
Onsite Waste Treatment
Offsite Waste Disposal
Total
13,866
2,943
1,795
0
Negligible
1,440
20,044
17,300
10,712
2,711
665
1,032
2,624
35,044
 * Based on 2,080 bbl/yr.
 and discharged downstream. This is done
 without compromising the cleaned  product
 quality, and no additional skill  (above that
 required to operate the old processes) is re-
 quired to operate the automated washer. Parts
 cleaned in the  automated  washer  can be
 either  electroplated or sent out as finished
 products.
    One current limitation is that the automated
 washer cannot yet totally substitute for the
 three older processes. Certain delicate parts
 have to be sent through the vapor degreaser
 and some difficutt-to-clean parts have to be
 processed through the hand-aqueous washer.
 Most jobs that can be run on the older pro-
                      cesses can, however, be routed through the
                      automated  washer.  Thus  the  automated
                      washer is a good technology for metal finish-
                      ers  who  are  considering an  expansion in
                      capacity.
                        In summary, use of the automated washer
                      results  in good  product quality,  increased
                      pollution prevention,  and economic savings.
                      An added incentive for using the automated
                      aqueous process is its potential  to  reduce
                      liability as a result of  reducing solvent  use.
                        The full report  was submitted in fulfillment
                      of Contract  No. 68-CO-0003 by Battelle un-
                      der the sponsorship of the U.S. Environmen-
                      tal Protection Agency.
 Table 4.  Operating Costs of Alkaline Tumbling and Automated Washing
 Cost Element
                    Alkaline Tumbling Costa
                            ($/Yr)
Labor                       18,720
Energy                       2,847
Chemicals                    2,434
Water                        4,700
Onsite Waste Treatment        7,299
Offsite Waste Disposal         	0_
  Total                       36,000

3  Based on 3,120 bbl/yr.
                         Automated Washing Cost3
                                  ($/Yr)

                                 10,380
                                  6,427
                                  1,626
                                   399
                                   619
                                 1+57A
                                 21,025
Table 5. Operating Costs of Hand-Aqueous Washing and Automated Washing
Cost Element
Labor
Energy
Chemicals
Water
Onsite Waste Treatment
Offsite Waste Disposal
 Total
Hand-Aqueous Washing Cost'
           ($/Yr)

          16,640
           3,256
          33,134
           1,213
           2,140
          	Q
          56,383
Automated Washing Cost'
         ($/Yr)

        6,920
        4,285
        1,084
          266
          413
        LQ50_
       14,018
' Based on 2,080 bbl/yr.
                                                                                          'U.S. Government Printing Office: 1992— 64B-080/60134

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A.R. Gavaskar, R.F. Olfenbuttel, J.A. Jones, and T.C. Fox are with Batelle,
    Columbus, OH 43201
Lisa Brown is the EPA Project Officer (see below).
The complete report, entitled "An Automated Aqueous Rotary Washer for the
    Metal Finishing Industry," (Order No. PB92-228469/AS; Cost: $19.00,
    subject to change) will be available only from:
        National Technical Information Service
        5285 Port Royal Road
        Springfield, VA 22161
        Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
        Risk Reduction Engineering  Laboratory
        U.S. Environmental Protection Agency
        Cincinnati, OH 45268, NC 27711
  United States
  Environmental Protection Agency
  Center for Environmental Research Information
  Cincinnati, OH 45268

  Official Business
  Penalty for Private Use
  $300
     BULK RATE
POSTAGE & FEES PAID
         EPA
   PERMIT No. G-35
  EPA/600/SR-92/188

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