United States
                          Environmental Protection
                          Agency
                          Research and Development
            Risk Reduction
            Engineering Laboratory
            Cincinnati, OH 45268
            EPA/600/S-92/047   October 1992
                          ENVIRONMENTAL
                          RESEARCH   BRIEF
                     Waste Reduction Activities and Options for a
                    Manufacturer of Commercial Refrigeration  Units
                                   Kevin Gashlin and Daniel J. Watts*
Abstract
The U.S. Environmental Protection Agency (EPA) funded a project
with the New Jersey Department of Environmental Protection and
Energy (NJDEPE) to assist in conducting waste minimization as-
sessments at 30 small- to medium-sized businesses in the state of
New Jersey. One of the sites  selected was a facility that manufac-
tures commercial refrigeration  units. The manufacturing operations
include design, metal working, metal finishing, and bbwing of poly-
urethane foam into panel jacketing for insulation purposes. A site
visit was made in 1990 during  which several opportunities for waste
minimization were identified. Options identified included new tech-
niques to reduce CFC emissions from foam manufacture, new foam
production cleaning techniques to reduce methylene chloride usage,
improved painting techniques to reduce VOC emissbns, and reduc-
tion of solvent wastes from general cleaning  procedures. Imple-
mentation of the identified  waste  minimization opportunities
was not part of  the program. Percent waste  reduction, net
annual savings,  implementation costs  and  payback periods
were estimated.

This Research Brief was developed by the Principal Investiga-
tors and EPA's Risk Reduction Engineering Laboratory in Cin-
cinnati, OH, to announce key findings  of this  completed as-
sessment.


Introduction
The environmental issues facing industry today have expanded
considerably beyond traditional concerns. Wastewater, air
emissions,  potential soil and groundwater contamination, solid
waste disposal, and employee health and safety have become
increasingly important concerns. The management and dis-
posal of hazardous substances, including both process-related
* New Jersey Institute of Technology, Newark, NJ 07102
wastes and residues from waste treatment, receive significant
attention because of regulation and economics.

As environmental  issues have become more  complex, the
strategies for waste management and  control  have become
more systematic and integrated. The positive  role of waste
minimization and pollution preventbn within industrial operations
at each stage of  product life is recognized throughout the
world. An ideal goal is to manufacture products while generat-
ing the least amount of waste possible.

The Hazardous Waste Advisement Program (HWAP) of the
Division of Hazardous Waste Management, NJDEPE, is pursu-
ing the goals of waste minimization awareness and program
implementation in the state. HWAP, with the help of an EPA
grant from the Risk Reduction Engineering Laboratory, con-
ducted an Assessment of Reduction and Recycling Opportuni-
ties  for Hazardous Waste (ARROW) project.  ARROW was
designed  to assess waste minimization  potential across  a
broad range of New Jersey industries. The project targeted 30
sites to perform waste minimization assessments following the
approach outlined  in EPA's Waste Minimization Opportunity
Assessment Manual (EPA/625/7-88/003). Under contract to
NJDEPE, the Hazardous Substance Management Research
Center at the New Jersey Institute of Technology (NJIT) as-
sisted  in  conducting the assessments. This research brief
presents an assessment of the manufacturing of commercial
refrigeration units (1 of the 30 assessments performed) and
provides recommendations for waste minimization options re-
sulting from the assessment.


Methodology of Assessments
The assessment process was coordinated by a team of techni-
cal staff from  NJIT with experience in process operations,
basic chemistry, and environmental concerns and needs. Be-
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cause the EPA waste minimization manual is designed to be
primarily applied by the in-house staff of the facility, the degree
of involvement of the NJIT team varied according to the ease
with  which  the  facility staff could  apply the manual.  In some
cases, NJIT's  role  was  to  provide  advice. In others,  NJIT
conducted essentially the entire evaluation.

The  goal of the project was to encourage participation in the
assessment process by management and staff at the facility.
To do this, the participants were encouraged to proceed through
the organizational steps outlined in  the manual. These steps
can be summarized as follows:

   • Obtaining corporate commitment to a waste minimization
    initiative
   • Organizing a task force or similar group to carry out the
    assessment
   • Developing a policy statement regarding waste minimiza-
    tion for issuance by corporate management
   • Establishing tentative waste reduction  goals to be achieved
    by the  program
   •  Identifying waste-generating sites and processes
   • Conducting a detailed site inspection
   • Developing a list  of options which may lead to the waste
    reduction goal
   •  Formally analyzing the feasibility of the various options
   •  Measuring the effectiveness of the options and continuing
    the assessment.

Not every facility was  able to follow these steps as presented.
In each case, however, the identification of  waste-generating
sites and processes, detailed site inspections, and development
of options was carried out. Frequently, it  was necessary for a
high degree of involvement by NJIT to accomplish these steps.
Two common reasons for needing outside participation were a
shortage of technical  staff within the company and a need to
develop an  agenda for technical action before  corporate com-
mitment and policy statements could  be obtained.

It  was not  a goal of the  ARROW project to participate in  the
feasibility  analysis or implementation  steps. However, NJIT
offered to provide advice for feasibility analysis if requested.

In each case, the NJIT team made several site visits to  the
facility. Initially, visits  were made to  explain the EPA manual
and to encourage the facility through the organizational stages.
If  delays and complications developed, the team offered assis-
tance in the technical review, inspections, and option develop-
ment.

No sampling or laboratory analysis was undertaken  as part of
these assessments.


Facility Background
The facility is a manufacturer of commercial  refrigeration units
typically  used for food storage and  sale. The  manufacturing
process involves creation of  the metal framework and surfaces
of the final unit, priming and painting of the unit, installation of
the refrigeration components, and blowing  in polyurethane foam
which hardens  into rigid insulation. The facility  is located in an
urban area and employs  200-300  people.


Manufacturing Processes
The  production process for the refrigeration units can be divided
into  three general  sections—sheet metal  cutting and forming,
metal coating and curing, and blowing of foam insulation. Each
of the steps results in the creation of different types of waste.

The  sheet metal cutting and forming  step involves cutting,
punching, and molding  to form the desired shape for the unit.
While this portion of the  manufacturing process does  not directly
result in  significant  quantities of  waste (particularly because
care is taken in laying out metal pieces to minimize any waste
from that source) the machinery used to accomplish the metal
cutting and forming does require maintenance. This machinery
care results  in the  generation of about 1,400 gal of  waste
lubricating oil each year. This oil  comes from the engine  and
gear box oil changes.

The  cut  and formed metal is finished  in three stages, all of
which are  required  to  provide the type and quality of finish
desired by the manufacturer. The first step is degreasing of the
metal surface using a  hot caustic cleaner.  The degreasing  is
necessary to remove the anti-oxidant protective oils which are
applied to the sheet metal to prevent  corrosion between the
sheet metal manufacture and the time  it is  used. The second
step is  priming  the metal  using  zinc phosphate. The  zinc
facilitates the retention  of the finish coat to  the  metal surface.
The  finishing coat is a high solid, solvent-based  paint.  The
color of  the  paint applied  varies depending upon customer
request.  This variability results in frequent  color changes on
the  manufacturing  line. The  paint is  sprayed on using an
electrostatic  system  reported to  be  approximately 81%  effi-
cient. When necessary the paint is thinned using isobutylcarbitol.
Equipment is cleaned as required by the color changes. Xylol
is used to clean pumps and other auxiliary equipment,  and
toluol is  used to clean  the hoses  leading to the spray system
from the  paint reservoir.

The  insulating polyurethane foam  is produced at the facility by
combining  a polyol,  diphenylmethane diisocyanate,  and
trichlorofluoromethane  (R-11). While the exact formulation  is
proprietary, it is known  that the R-11  represents about 10%  of
the mix.  In addition, another chlorofluorocarbon, R-12,  is used
to blow  the  mixture into the steel panel  jacketing. R-11  is
encased  in the cured solid structure of the mixture and, because
of its heat transfer characteristics, helps provide the insulating
characteristics of the mixture. According to  the  supplier of the
chemicals used for generation of the polyurethane foam, about
40% of the R-11 and  R-12  used  in the process escapes into
the air during the manufacture and curing phases  and  cannot
be reduced significantly without development of new foaming
technology.

The foam mixture cures very rapidly. The residual mix adhering
to the foam  blowing equipment would also cure and harden
within a few minutes thereby ruining the equipment. To prevent
this  from occurring, the equipment is cleaned with 0.5 to 1.0
gal of methylene chloride after each  unit is insulated. About
13,000 Ib of the washing mixture  is generated annually. Emis-
sions of  methylene chloride to the air  from evaporation have
not been quantified.


Existing Waste Management Activities
The company  has  already  invested  in  equipment which  is
designed to improve efficiency and help prevent pollution. The
acquisition of the electrostatic painting equipment demonstrates
the interest by the company  in improving the efficiency of the
paint transfer process  and  in reducing the proportion  of the
material which is wasted.

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The waste lubricating oil from  maintenance and  repai; of the
machinery used  in metal cutting and shaping is collected and
sent offsite for disposal.  The  annual volume  of oil  is about
1,400 gal. The oil changes generally occur at regularly sched-
uled intervals.

The waste stream from the degreasing operation has an an-
nual volume  of  about  2900  Ib  and  is  also  sent offsile for
treatment.

The waste streams from the coating operations are  somewhat more
complex.  Excess primer  and solids from  surface smoothing are
captured in water and then filtered out before the bulk of the water is
sent to the sewerage authority for treatment. Information about the
volume of water from this  use could not be obtained The quantity of
the filtered solids  represents about 500 Ib/yr. This  appeared to be
too small an amount to  lead to consideration of metal >eoovery
activities. The  finish coat process uses a paint which ha?  a high
solids content and is solvent-based. The high solids means that the
solvent content is relatively low (2.1-2.8 Ib/gal). Performance require-
ments will not allow the substitute use of a water-based paint at this
time. There is not a substitute product available which will albw the
manufacturer to maintain the quality of the finish coat of the p-oduct.
As indicated previously, the paint is sprayed on using an electro-
static system. When the painting equipment is cleaned, xyloi B used
to clean the pumps and other auxiliary equipment and toluo  is used
to clean the hoses leading to  the  spray system from  the  paint
reservoir. The two solvent  wastes  are combined, accumulated  in
drums and disposed of as  hazardous waste. About 18,000 gai  of
this waste is generated annually.

The insulating foam production operation generates a waste stream
from the cleaning of the generation and blowing equipment. About
13,000 Ib of the methylene  chloride washings are  generate annu-
ally and are sent offsite for disposal as hazardous waste.


Waste Minimization  Opportunities
The type of waste currently generated by the facility, the sojrce of
the waste, the  quantity of the waste and the annual treatment and
disposal costs are given in Table 1. This particular facility presents a
challenge in terms of  describing and presenting  opportunities for
waste minimization. For example, the production of  the polyurethane
insulating foam results  in  a  measurable waste stream only in terms
of clean  up solvents. On  the other hand, there is a process related
air emission of a CFC  which is thought to be of significant environ-
mental  concern.  The  available technological alternatives  present
some difficulties. Similarly, some improvements in  the painting pro-
cess will require significant capital investment in  equipment which

 Table 1.  Summary of Current Waste Generation
 Waste Generated

 Waste Oil


 Water/Hydrocarbon Mixture


 Zinc Containing Solids
 Hydrocarbon Mixture
 (Toluol and Xytol)

 Methylene Chloride
 Solution
Source of Waste
Repair and maintenance of meta'
cutting and forming equipment

Hot caustic degreasing
operation

Residues and smoothing solids
from priming operation

Equipment cleaning from spray
painting

Cleaning of polyurethane foam
generation system
                                      cannot be easily quantified presently  based upon the information
                                      currently available.

                                      Table 2  shows the opportunities for waste  minimization recom-
                                      mended for the facility. The type of waste, the minimization opportu-
                                      nity, 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 at the facility and
                                      possible waste reduction depend on the level of activity of the facility.
                                      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. It should  also be  noted that the
                                      savings given for each opportunity  reflect the savings achievable
                                      when implementing  each waste minimization opportunity indepen-
                                      dently  and do not  reflect  duplication of savings that would  result
                                      when the opportunities are implemented  in a package.

                                      The cost  savings are calculated both  in terms of avoided costs of
                                      waste  disposal  and recovery of any  value of raw  material used
                                      again. Also, no equipment depreciation is factored into the calculations.

                                      There  are some commercially available  alternatives to the present
                                      insulating foam  process. The insulating process requires  a gas for
                                      two purposes, one to generate foaming during the polymerization
                                      process and  another to force the foam, prior to hardening, into the
                                      area where  insulation is  required. The CFC's that are  presently
                                      being used do this job well. The relatively low boiling point leads to
                                      the  foaming   as  a  result  of  vaporization  caused by  the heat of
                                      reaction of the polymerization. Some of the CFC is entrained in the
                                      foam and contributes to the insulation performance of the product.

                                      The use of other materials may result  in loss of this added boost to
                                      the  insulating characteristics  of the foam.  One of  the  available
                                      alternative technologies uses a hydrochlorofluorocarbon (HCFC) as
                                      the blowing agent. This class of materials has reduced impact on the
                                       upper atmosphere as compared to CFC's. The propulsion gas used
                                       in this system is nitrogen. Another alternative uses a proprietary
                                      composition and mixing approach which appears to use nitrogen as
                                       both blowing  and propulsion  agent. The cost of raw materials and
                                       equipment for this application is approximately  the  same  as the
                                      currently  used CFC technology. However, the insulation effective-
                                       ness of  the  resulting foam is only about 95% that of the existing
                                      foam material. This means that either the refrigeration units need to
                                       be redesigned to allow incorporation of an increased thickness of
                                       insulation or that the units will be in operation for longer periods.
                                       Either way more energy will be used because additional units may
Annual Quantity
  Generated

   1,400 gal


   2,900lb


     500 Ib


  18,000 gal


   13.000 Ib
  Annual Waste
Management Costs
       $600
       3200
        250
     22,000
                        16,000

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 Table 2.  Summary of Recommended Waste Minimization Opportunities

                       Minimization Opportunity              Annual Waste Reduction
Waste Stream
Reduced
                                                          Quantity
                                                                       Percent
                                Net       Implementation    Payback
                          Annual Savings       Cost         Years
 Waste Oil
 Hydrocarbon Mixture
 Methylene Chloride
 Solution
                      Change to synthetic formula
                      to lengthen time between
                      oil changes

                      Keep separate the xylol and
                      toluol streams.  Acquire onsite
                      distillation capability.  Reuse

                      Change to less hazardous solvent
                      cleaning system available from
                      the vendor of the polyurethane
                      components. The newer solvent
                      can be filtered and reused, reducing
                      the need to purchase and dispose of
                      cleaning solvent.
                                                            700 gal
14,400 gal
 13,000 Ib
                 50
 80
100
              $850
             31,000
                                             $2,800
                                                                                                      20,000
3.3
0.6
             19,400          5,000          0.25
            (This option is somewhat more complex in
            the determination of savings and payback
            period.  While all of the methylene chloride
            waste stream will be eliminated, another waste
            stream will be established.  However, without
            some site experience, it is difficult to estimate
            the volume. If we assume an 80% reduction in the
            volume because of recycling and assume that
            disposal costs and chemical costs are the same as
            with methylene chloride, then the annual savings
            are $ 15,800 and the pay back period will be
            0.3 yr. There will also be another waste stream
            resulting from the filtration of solids from the
            recycled solvent. Management costs for that
            stream will also reduce the net savings.)
 ' Savings result from reduced raw material and treatment and disposal costs when implementing each minimization opportunity independently.
 be required  to  refrigerate the same  volume of material  or the
 refrigeration equipment will run bnger.  It is difficult to determine, at
 this level of analysis, which choice is more  environmentally favor-
 able. However, the rapid escalation of CFG taxes and the impending
 ban on production and use of the materials will require a change at
 this facility.

 It  appeared  that the electrostatic paint system which had been
 installed needed some additional adjustments in order to operate at
 its maximum high transfer efficiency. For some painting operations,
 portions of the spray were directed at  areas where there was not
 metal to be painted  resulting in a bss of  the paint  and increased
 VOC burdens. It is suggested that the number of spray nozzles be
 increased resulting in more precise control of the area being covered
 by paint. In addition, use of an optical recognition and control system
 could result in more  savings. Discussions with the manufacturer of
 the painting system and with suppliers of optical control systems will
 be necessary to determine  if this  is feasible and to  obtain  a cost
 estimate.

 Other coating alternatives should  continue to be investigated. It is
 likely that none of them would be acceptable  at present because of
 performance requirements. On the other hand, progress in broaden-
 ing the technology of coating materials should be monitored. The
 goal of such changes is to reduce the level of VOC and associated
 hazardous waste streams. Powder coating virtually eliminates sol-
 vent, and any overspray is simply swept up and reused. The  capital
 costs are comparable to those of the electrostatic spray system just
 acquired by  the company.  Another emerging technology  utilizes
 supercritical carbon dioxide as the carrier for  the solids in coatings.
 The coating system requires  special equipment for production of the
 supercritical carbon dioxide. Generally, up to 70%  of the volatile
 solvents can  be replaced resulting in VOC reductions of the same
 amount. Additionally, it is reported that superior atomization  occurs
 using this technology relative to solvent systems, resulting in fewer
spraying defects.
                                                                 Regulatory Implications
                                                                 Changes in regulatory emphasis can be expected to have an impact
                                                                 on the manufacturing process at this facility. Particularly, the  im-
                                                                 pending ban on production  and use of most CFC's will cause a
                                                                 change in the production of the insulating foam. The technical and
                                                                 chemical details of this change are largely out of the hands of  the
                                                                 company. They will acquire the equipment and supplies from some-
                                                                 one else. In terms of the volume of waste generated at the facility, it
                                                                 is not clear whether this impending change will have a net positive or
                                                                 negative effect. It may take larger quantities of some solvent to clean
                                                                 the required equipment for example. The point is that regulatory
                                                                 changes do not always albw uniform movement to waste reduction.
                                                                 This is particularly true when cross media transfers of waste genera-
                                                                 tion are considered. A change in a process such as this which has
                                                                 air emissions and may require a change in  an  air permit may be
                                                                 delayed while the air permitting process  considers and approves (or
                                                                 disapproves) the application  for a change. This  facility will also be
                                                                 impacted by the increased regulatory scrutiny on methylene chbride.
                                                                 There are some alternatives available for this solvent which is used
                                                                 for cleaning purposes at this  facility. It is not clear however, without
                                                                 some field trials whether the  net effect on waste generatbn will be
                                                                 positive or negative.  Methylene chloride is a particularly good solvent
                                                                 for the cleaning application here.

                                                                 This  Research Brief summarizes a part of the work done under
                                                                 cooperative Agreement  No.  CR-815165  by  the New Jersey
                                                                 Institute  of  Technology  under  the  sponsorship of the  New
                                                                 Jersey  Department of Environmental Protection and Energy
                                                                 and the U.S. Environmental  Protection Agency. The EPA Project
                                                                 Officer was  Mary Ann Curran. She can be reached at:

                                                                         Pollution Prevention Research Branch
                                                                         Risk Reduction Engineering  Laboratory
                                                                         U.S.  Environmental Protection Agency
                                                                         Cincinnati, OH 45268
                                                                  ' Mention of trade names or commercial products does not constitute endorsement
                                                                   or recommendation for use.
     •&U.S. GOVERNMENT PRINTING OFFICE: 1994 - 5SO-067/ttOI93

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