oEPA
                        United States
                        Environmental Protection
                        Agency
                        Research and Development
                                   Risk Reduction
                                   Engineering Laboratory
                                   Cincinnati, OH 45268
                                   EPA/600/S-92/039  Oct. 1992
ENVIRONMENTAL
RESEARCH   BRIEF
                     Waste Reduction Activities and Options for a
                            Manufacturer of Finished Leather

                                 Patrick Eyraud 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 assessments at 30 small- to medium-sized busi-
nesses in the state of New Jersey. One of the sites selected
was a manufacturer of finished leather. A site visit was made in
1990 during which several opportunities for waste minimization
were identified. Recommendations included 1) changeover to
water-based coatings; 2) installation of a solvent recovery/
reuse capability; 3) use of a hand pump to reduce spillage
during transfer and physical layout considerations to reduce
the distances materials must be moved; 4) reducing the volume
of the container for test mixes; 5) improvements to the computer-
controlled spray-coating operation to reduce overspray; and 6)
the use of covers over formulated coating mixtures to reduce
air emissions. Implementation of the identified waste minimiza-
tion opportunities was not part of the program. Percent waste
reduction, net annual savings, implementation costs and pay-
back 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-
* New Jersey Institute of Technology, Newark, NJ 07102
                        posal of hazardous substances, including both process-related
                        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 prevention 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 NJIT assisted in conducting the assessments.  This
                        research brief presents an assessment  of a manufacturer of
                        finished leather (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,
                                                                             Printed on Recycled Paper

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 basic chemistry, and environmental concerns and needs. Be-
 cause the EPA waste minimization manual is designed to be
 primarily applied by the inhouse 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, NJITs 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.


 Facility Background
 The plant produces finished leathers which are  sold to manu-
 facturers of leather goods such as handbags, belts, shoes, and
 other items.  The operation of the  plant varies according  to
 customer demand. Many different colors, textures, and designs
 must be incorporated  into the product to meet varying cus-
 tomer requirements, forcing the operation of several special
 production  steps  on an irregular basis.  The facility  formerly
 tanned raw hides, but that process has been phased  out as a
 result of changing supply and market conditions.

 Manufacturing Process
This facility receives tanned leather from various sources and
transforms  it into  a product  of higher  commercial  value by
 applying  various coatings and other surface  modifications to
 make it more usable and appropriate for finished consumer
 products. The raw materials include, in addition to the leather
 itself, various  water- and solvent-based coatings as well as
 some specialized  colorants and other surface modification
 products. The solvents in the  coatings typically  are aromatic
 and aliphatic hydrocarbons, esters, and alcohols.

 The following processes  are carried out in the facility but not
 every hide necessarily receives each finishing process.

     Back Coating
     Base Coating
     Plating Top
     Tipping (hand made)
     Color Top
     Clear top

 A typical  hide  in  the manufacturing process might receive the
 following  finishing steps.

 Newly received hides are prepared for finishing by washing,
 retanning if necessary, and drying. The aqueous wastes from
 these steps are sent to the POTW with regular monitoring to
 assure compliance.

 Some hides undergo surface modification by mechanical buff-
 ing. The resulting dust is  classified as a hazardous waste and
 is disposed of offsite.

 The back coating step applies essentially the final finish to the
 back of the leather while  the base coating of the smooth side
 serves as the primer for additional finishes to  be applied. The
 coatings are applied using an  automated spray  system. The
 facility has  shifted largely to water-based coating for  these
 steps resulting in a significant decrease in solvent use. Any
 over-spray is  captured by a water-screen  or by filters and
 disposed  of offsite.

 The next  coating steps are accomplished using solvent-based
 materials. No satisfactory  non-solvent based coatings have yet
 been identified for these finishing steps. The  applied finishes
 are thermally dried with venting of solvent vapors to the  atmo-
 sphere.

 The final steps in the manufacturing process are ironing, grad-
 ing,  measuring, and shipping—operations which  are not sig-
 nificant waste-generating activities.


 Existing Waste Management Activities
 The facility has  shifted to the use of water-based coatings where
 possible. Moreover, the technical staff continues  to evaluate new
 commercial reduced-solvent products in order to  make further re-
 ductions. An optical/computer interfaced system has been used to
 determine the shape and position of each hide presented for coating
 which is used  to  control the automated spray  coating system,
 resulting in significant reduction of overspray.


 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 (where known and available) are given  in Table 1.

Table  2 presents the opportunities for  pollution prevention
which  were  identified  during the assessment.  The type of
waste, the minimization opportunity, and the  possible  waste

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 reductions, are presented in the table. When available or esti-
 mable, the associated saving, and implementation costs along
 with payback times  are  also  given,  However,  because the
 feasibility analysis  was to be  carried out by the staff of the
 facility, that information is not always readily available.


 Additional Options Identified
 In addition to the options previously discussed two other options
 were suggested.  It  was observed that the wooden pallets and
 cardboard used for shipping hides  to the facility might have
 increased value if recycled. Second, the future use of a spray
 coating system based upon supercritical carbon dioxide as a
 solvent/carrier was identified. However, such a system depends
 not only on the availability of  the hardware, but also on the
 manufacture of coatings compatible with the spray system and
 capable of providing the required quality for the finished leather.
 Such coatings are not presently available.


 Regulatory Implications
 The significant regulatory issue at a facility such  as this is the
 impending requirement for more efficient air emission control
                                    practices. This concern is driving the interest in pollution pre-
                                    vention. Unfortunately, the apparent best solution—changing to
                                    water based coatings—is  not technically feasible. It is unknown
                                    if the perhaps next best solution—solvent capture and recovery
                                    from the process air emissions—would  be acceptable to the
                                    regulatory authorities in light of better known thermal oxidation
                                    systems which have less  source reduction potential.  If a facility
                                    has capital  resources to install only one system, it is uncertain
                                    what position and role a regulatory authority will take.

                                    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
Table 1.  Summary of Current Waste Generation
Waste Generated
Washing Waters
Buffing Dust
Evaporated Coating
Source of Waste
Cleaning of
incoming hides
Mechanical abrasion
of hide surface
Application of back
Annual Quantity
Generated
130,000 gal
<100lb
130 tons
Annual
Costs
$30
$325
These are either
Solvent
Solvents and Coatings
coating, base coating,
plating top, color top,
and clear top to hides.
Most solvent evaporation
occurs during oven assisted
drying. Some loss also
occurs as a result of
spills and leaks during
material mixing and trans-
fer.

Excess coatings and solvent
from equipment cleaning
12,300 gal
                                                                                   fugitive emissions
                                                                                   or regulated emissions
                                                                                   to the atmosphere, and
                                                                                   therefore have no management
                                                                                   costs except the loss of
                                                                                   potential recovery value.
$61,000
                                                                           ft U.S. GOVERNMENT PRINTING OFFICE: 1*94 - 5S0-4M7/MK8

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Table 2.  Summary of Waste Minimization Opportunities

Waste Generated       Minimization Opportunity
                                   Annual Waste Reduction         Net       Implementation      Payback
                                   Quantity        Percent   Annual Savings       Cost           Years*
Buffing Dust
Evaporated Solvent
Solvents and
Coatings

Evaporated Solvent
Sale for beneficial reuse
in resin-based composite
product.

Continue changeover to water
based coatings subject to
development of satisfactory
materials by coating manu-
facturers.

Prepare test formulations in
smaller quantities.

Reprogram automated spray
coating equipment to compensate
for required angle spraying.
100 Ib
1.3 tons
300 Ib
100%
10%
               2%
$325
                                                            immed
  The savings will come from avoided treatment
  from an air emissions control system not yet
  installed. The facility is clearly dependent
  upon the coating production industry and can-
  not make progress in this area alone.
              $900
                                                            immed
up to 65% when
angle spraying is
required.
12.7 tons       9.7%
             $25,000        $5,000          0.2
          More savings will result from avoided treatment costs
          from the new control system not yet installed.
                      Install covers on coating
                      reservoir containers during
                      spray coating operations.
                                   variable depending
                                   upon solvent
                                   volatility
                                   500 Ib          0.2 %
                             $500
                            $1,000
                              2.0
                      Install solvent capture
                      system allowing capture
                      and reuse. Possibilities
                      include a carbon system
                      with steam distillation
                      regeneration capability
                      permitting recovery of
                      the captured solvent.
                      Distillation and reuse
                      of the solvent is possible
                      if the solvent mixture is
                      not too complex.  Difficult
                      mixtures may have to be distilled
                      offsite where more efficient
                      columns are available.
                                   up to 90%
                                   depending upon
                                   type of solvent.

                                   117 tons
                                                  90%
                            $200,000
                                                                              $300,000
                                            1.5
                                                               (A system of this type could serve as the emission
                                                               control device assuming that the regulatory
                                                               authority would approve it instead of more usual
                                                               equipment.)
 Savings result from reduced raw material, and treatment and disposal costs when implementing each minimization opportunity independently.
  United States
  Environmental Protection Agency
  Center for Environmental Research Information
  Cincinnati, OH 45268

  Official Business
  Penalty for Private Use
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  EPA/600/S-92/039

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