United States
                Environmental Protection
                Agency	
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
                Research and Development
EPA/600/SR-92/024   April  1992
EPA        Project Summary
                Automotive  and Heavy-Duty
                Engine  Coolant  Recycling  by
                Distillation

                Arun R. Gavaskar, Robert F. Olfenbuttel, and Jody A. Jones
                  Product quality, waste reduction, and
                economic issues were evaluated for a
                distillation technology designed to re-
                cycle automotive and heavy-duty en-
                gine coolants.  Coolant recycling was
                found to have good potential  as a
                means of waste reduction and to be
                economically viable. The product qual-
                ity achieved by this unit was promis-
                ing.  Product quality was evaluated by
                conducting selected performance tests
                recommended in ASTM D 3306  and
                ASTM D 4985 standards and by chemi-
                cally characterizing the spent, recycled,
                and virgin coolants.
                  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 objective of the U.S. Environmental
                Protection Agency (EPA)  and  the New
                Jersey Department  of  Environmental
                Protection's (NJDEP) Prototype Evalua-
                tion Program is to evaluate, in a typical
                workplace environment, examples of pro-
                totype technologies that have potential for
                reducing wastes. The goal of the engine
                coolant recycling study was to evaluate
                (a) the quality of the recycled coolant, (b)
                the waste reduction potential of the tech-
                nology, and (c) the economic feasibility of
                the technology.
                  The coolant recycling unit in this study
                was manufactured by Finish Thompson,
                Inc. (FTI)', Erie, Pennsylvania.  The unit
               ' Mention of trade names or commercial products does
                not constitute endorsement or recommendation for
                use. This document is intended for informational
                purposes only for the automotive repair industry.
(shown in Figure 1) operates on up to 15
gal of spent coolant  per batch.  Spent
coolant is poured into the distillation still
along with an additive to control boiling.
The  unit is switched  on and allowed to
operate until water and ethylene glycol
are distilled off into two  separate  clean
drums outside the unit.   This may take
.between 12 and 15 hours for a full 15-gal
load of spent coolant, depending upon the
amount of water present.  Water distills
out first at atmospheric pressure. As the
temperature rises,,the vacuum pump
switches on automatically and starts draw-
ing out the glycol.  The vapors are con-
densed by using tap  water as the heat
exchanger fluid.  A chiller is available as
an option, but was not  used in this testing.
The  condensate  enters the primer tank,
where it mixes with the primer (ethylene
glycol) and overflows into the "processed
glycol drum". Three gallons of distillation
residue collects at the bottom of the still
and  is  emptied  out,  typically after five
batches.
  The study was conducted in coopera-
tion with the New Jersey Department of
Transportation (NJDOT)  vehicle  mainte-
nance and  repair facility in Ewing, NJ.
Currently  all the  spent coolant at the
NJDOT garage (approximately 8, 812 gal/
yr) is shipped offsite for disposal.

Product Quality Evaluation
  Engine coolants are  intended to provide
protection against boiling, freezing, and
corrosion.  Through use, the coolants lose
some measure of these functions because
of the accumulation of contaminants and
the depletion of additives such as corro-
sion inhibitors and anti-foam agents. The
recycling process attempts to restore the
functions of the coolant to standards speci-
fied in ASTM D 3306-89  and SAE J1034
(for automotive coolant) and ASTM D 4985
and SAE J1941 (for heavy-duty coolants).
                                                                  Printed on Recycled Paper

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                                                                                          Pump
                                                   Optional
                                                   Water Chiller
Figure 1. Coolant cSstillation process.
  In addition to running batches of spent
coolant (primary batches), test batches in
which one or more characteristics  of the
coolant were intentionally altered (spiked
batches), were run to test the limits of the
recycling process.  All batches,  except
Batch 5, consisted of spent  coolant ob-
tained from  NJDOT. Batch 5 was spent
coolant obtained from a local radiator shop.
A blank, consisting of  equal portions of
virgin coolant and tap water, was also run
through the  unit.   Samples of the  virgin,
spent, and recycled coolant were collected
for analysis.
  Batches 3 and 4 were run at less-than-
full capacity to conserve time  and materi-
als.  Because both units shut off while 3
gal of residue remained, as they are pro-
grammed to do,  there was not enough
recycled coolant for sampling from each
individual  batch.   Hence,  residue from
Batches 3 and  4 was combined and re-
run.  This combined batch is henceforth
referred to as Batch 3/4.
  Results of the analyses were compared
against ASTM and/or SAE standards. Af-
ter recycling, the freezing point was mea-
sured by a hand-held refractometer, and
the ratio of processed water to processed
glycol was adjusted accordingly to meet
freezing point specifications.  As shown in
Tables 1 and 2, the pH and corrosiveness
of the  recycled coolant were also  within
specified limits.
  The spent and  recycled coolants were
characterized chemically and contaminant
levels were measured to determine if these
constituents affected performance. Table
3 shows the ilevels .of metallic contami-
nants.  The levels of calcium, magnesium,
iron, and zinc:were  reduced considerably
in the recycled coolant. Reduction in lev-
els  of  lead  and aluminum  could not be
estimated because of  |ow levels of these
metals in the, spent coolant and due  to
matrix  interference in the analysis.
  One limitation  of this  product  quality
evaluation was that the performance  of
the  recycled : coolant  from successive
batches processed on  the same recycling
unit  could not be assessed because the
five  batches were run on  five separate
units.  Evaluation of the recycled coolant
obtained after,running  several batches on
the same unit would be a good adjunct to
this study, especially because the primer
(ethylene glycbl) in the primer tank has a
diluting effect on the initial batches.  Later
batches may have slightly higher levels of
contaminants.

Waste Reduction  Potential
  Waste reduction potential was measured
in terms  of (a) volume reduction and (b)
pollutant  reduction.  Volume reduction ad-
dresses  the  gross  waste  streams  (i.e.,
spent coolant and spent filters); pollutant
reduction involves  individual  pollutants
(such as ethylene glycol and heavy  met-
als) contained in the waste stream.
  To estimate the amount of coolant that
NJDOT disposes of  annually, the amount
of  new coolant  that NJDOT purchases
annually  was i decreased by 10% to ac-
count for the environmental loss of cool-
ant through leaks in the vehicles' cooling
systems. Because the coolant is recycled
rather than  disposed of, the volume of
waste reduction for  NJDOT was calcu-
lated to be 8,812 gal.  The side streams
of the recycling process (residue) were
also accounted for in this evaluation.
  Since contaminants  (e.g.,  lead) con-
tained in the  spent coolant will reach  the
environment whether or not the coolant is
recycled (either through spent coolant  dis-
posal or residue disposal).  The measur-
able hazard reduction of recycling comes
from the amount of  ethylene glycol that
does not reach the environment or find its
way to disposal.  Ethylene glycol  is con-
sidered a hazardous waste in some states
(such as California).   Recycling coolant
offers considerable potential for reducing
the amount of ethylene glycol released to
the environment.

Economic Evaluation
  The economic evaluation took into  ac-
count the  capital and operating costs
(shown in Table 4) of the recycling equip-
ment, as well as the  savings provided by
decreasing the needed amount of  raw
materials (virgin  coolant and water) and
by reducing disposal costs. The purchase
price of the recycling unit at the time of
this evaluation was $5,115.  Because of
the relatively high price of virgin coolant
and the high volume of  virgin coolant pur-
chased by NJDOT, the payback period for
the recycling process was much  less than

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Table 1. pH (ASTM D 1287-85) and Corrosivify (ASTM D 1384-87) As M
Batch No. Description Sample' pH"
1,2 Primary
1 Primary
2 Primary
3/4 Spiked
5 Primary
Spent
Recycled
Recycled
Spiked
Recycled
Recycled
8.3
10.9
11.0
8.7
10.7
10.8
easured in Laboratory
Weight Loss per Specimen (ma)*"
Copper
0
0
0
0
0
0
Solder
2
4
6
4
6
7
Brass
1
3
1
2
2
1
>- Steel
0
1
0
0
0
o
C. Iron
4
2
0
72
1
1
C.AI
1
5
1
1
0
0
a A recycled sample indicates 50:50 processed glycol and processed water, plus additives. No spent sample analyzed for Batch 5.
" SAE Standardfor pH 7.5 to 11.0
c Average of triplicate results.
° ASTM D 3306 Standard for Corrosion:
  (allowable weight loss per specimen)
  Copper = 10 mg max                        Steel = 10 mg max
  Solder = 30 mg max                         Cast Iron = 10 mg max
  Brass = 10 mg max                          Cast Aluminum = 30 mg max
Table 2.  Corrosion of Cast Aluminum Test (ASTM 4340-89) Results
Batch No.
1,2
1
2
Description
Primary
Primary
Primary
Blank
Sample '
Spent
Recycled
Recycled
Virgin
Corrosion Rate
mg/crrf/wk"
16.8
0.8
0.9
0.9 .
* A recycled sample indicates 50:50 processed glycol and processed water, plus additives. " •'-• ''
" SAE Standard: Corrosion rate not greater than LOmg/crrf/wk
Tables. Concentrations of Metallic Contaminants in Coolant
ppm in Coolant* , ,
Batch No.
1,2,3/4
1

2
3/4
5
Description
Primary
Primary

Primary
Spiked
Primary
Sample '
Spent
Recycled
Processed
water
Recycled
Recycled
Processed
glycol
Aluminum
<0.19
0.63
<0.19
0.88
1.01
1.20
Calcium
0,46
<0.20
<0.20
<0.20
<0.20
<0.20
Copper
2.34
0.081
<0.036
0.32
0.21
0.15
Iron
0.28
<0.04
0.04
0.04
0.63
0.098
Lead
0.34
2.88
<0.2
1.0
1.59
2.9
Magnesium
0.78
<0.20
<0.20
<0.20
<0.20

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1 yr.  Therefore, coolant recycling would
make economic sense.

Conclusions
  This evaluation shows that automotive
coolant recycling has much potential as a
waste reduction option. The NJDOT facil-
ity where this evaluation was conducted
could  potentially reduce spent  coolant
waste volume from over  8,000 gal to ap-
proximately 400 gal/yr. The recycled prod-
uct in this evaluation also fared very well
in the  selected ASTM performance tests
and the chemical characterization analy-
ses. Boiling point, freezing point, pH, and
           corrosion resistance  functions of the cool-
           ant were restored to specifications. Met-
           als, salts, and organic contaminants were
           considerably reduced in the recycled cool-
           ant.  Recycling was found to be economi-
           cally viable for the NJDOT facility, with a
           return on investment (ROI) of over 300%
           in the first year.
             Figure 2 describes how the ROI varies
           depending on the amount of spent cool-
           ant generated annually by the user.  If a
           user generates 100  gal of coolant annu-
           ally, the initial investment may not be re-
           coverable. A slightly larger generator, with
           500 gal/yr of spent coolant, would have a
                                 payback period of approximately 7 yr (ROI
                                 greater than 15%).  The ROI improves as
                                 the amount of spent coolant generated
                                 becomes larger. The manufacturer plans
                                 to improve  economics  by reducing the
                                 heating requirement and also by eliminat-
                                 ing the No Foam™ additive in the 1992
                                 model of this unit.  Also, as  regulations
                                 become  more  stringent,  the economical
                                 attractiveness of the  technology can be
                                 expected to grow.
                                   The full report was submitted in fulfill-
                                 ment of Contract No. 68-CO-0003, Work
                                 Assignment 0.06, by Battelle Memorial In-
                                 stitute under  the sponsorship of the U.S.
                                 Environmental Protection Agency.
Table 4. Major Operating Costs
        Item
Quantify/yr
Unit Cost, $
Total Cost, $fyr
Current Practice

Disposal:

 • Coolant                      8,812 gal


 • Drums                          160

 • Labor (no overheads)             160 hr


Recycling

No-Foam™ (additive)              700 bottles

FTI Treatment™ (additive)          700 bottles

Water (for condenser, flush)       252,140 gal

Electricity                      35,990 /cwfr

Labor (no overheads)              257 hr

Residue Disposal                  420 gal


Drums                             8
                      $140/
                   55 galdrum

                       30

                       15
                      1.86

                      8.60

                     .0011

                      .12
                    22,431


                     4,800

                     2,400
                     $4SO/
                   55 gat drum

                       30
                 Total 29,631'



                     1,302

                     6,020

                     277

                     4,319

                     3,855

                     3,436


                     240

                  Total 19,449=
' This total does not include maintenance costs or overhead.

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  I

  1
  I
     500
     400
     300
     200-
     -700
                                                                                                            Coolant = 7000 gal
                                                                                                                   A
                                                                                                            Coolant = 500 gal
      100-
                                                                     Year
                                                                                                                                 10
Figure 2. Summary of ROI for various sizes of shops generating spent coolant.
                                                                                    •frll.S. GOVERNMENT PRINTING OFFICE: 1992 - 648-080/40Z36

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   A.R. Gavaskar, R.F. Olfenbuttel, andJ.A. Jonesare with Battelle Memorial Institute,
     Columbus, Ohio 43201-2693.
   Paul Randall is the EPA Project Officer (see below).
   The complete report, entitled "Automotive and Heavy-Duty Engine Coolant Recy-
     cling by Distillation," (Order No. PB92-153 444/AS; post: $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
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati, OH 45268
     BULK RATE
POSTAGE & FEES PAID
         EPA
   PERMIT NO. G-35
Official Business
Penalty for Private Use $300
EPA/600/SR-92/024

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