United States
             Environmental Protection
               Office of Solid Waste
               and Emergency Response
               Washington, D.C. 20460
August 1989
             Solid Waste
Waste Minimization
in Metals Parts Cleaning


Waste Minimization
Metal Parts Cleaning
United States
Environmental Protection

Office of Solid Waste
August 1989

                                This booklet provides information on ways to reduce wastes associated with
                                metal parts cleaning operations.  It was published by EPA's Office of Solid
                                Waste and Emergency Response and is part of EPA's waste minimization
                                program under the 1984 RCRA amendments.

                                Other EPA Waste Minimization Publications

                                Waste Minimization Benefits Manual
                                Manual for Waste Minimization Opportunity Assessments
                                Guide to Waste Minimization for the Paint Manufacturing Industry
                                Guide to Waste Minimization for the Pesticide Formulating Industry
                                Guide to Waste Minimization for the Commercial Printing Industry
                                (The latter three publications were developed jointly by EPA's Risk Reduction
                                Engineering Laboratory and the California Department of Health Services.)

                                This guide is advisory only. It is intended to be used by industrial personnel
                                responsible for metal parts cleaning operations in order to help them develop
                                approaches for minimizing wastes. Compliance with environmental and oc-
                                cupational safety and health laws is  the responsibility of each individual
                                business and is not the focus of this  document.  Mention of any product,
                                service, or process in this document is for  educational purposes only and
                                should not be considered an endorsement by the U.S. Environmental Protec-
                                tion Agency.

                                This document was prepared under contract 68-01 -7053 by Jacobs Engineering
                                Group Inc. The project team included Michael Callahan, Deborah  Hanlon,
                                Sally Lawrence, and Michael Meltzer under the direction of Carl Fromm. The
                                design and layout was done by Vincent P. Medina of Jacobs Engineering
                                Group Inc.

                                The following people provided valuable reviews of this document. EPA ap-
                                preciates their assistance in this important effort:  Stephen Evanoff, General
                                Dynamics Corporation; Brad Gruss, Vice President, Fremont Industries; Jerry
                                Kohl, North Carolina State University;  Richard Randolph, Dow Chemical
                                Corporation; Ed Rodzewicz, Parker-Anchem Corporation; Marvin Weast,
                                Retired Director of R & D, Turco Purex, Pennwalt Corporation; and Kathleen
                                Wolf, Rand Corporation/Source Reduction Research Partnership.

                                In addition, we would like to thank E.I. du Pont de Nemours and Company for
                                granting permission to reprint an illustration which appears as Figure 7 of this

 Waste  Minimization  in  Metal  Parts  Cleaning  Operations
                               Acknowledgments	ii

                               1.      Introduction	1
                                      1.1 What is Waste Minimization?	2
                                      1.2  Incentives for Minimizing Waste	3
                                      1.3  Waste Minimization Assessments	4

                               2.      Waste Minimization in Parts Cleaning Operations	6
                                      2.1 Overview of Parts Cleaning	6
                                      2.2 Waste Minimization Strategy for Parts Cleaning	8
                                         Can Cleaning Be Avoided?	8
                                         Select the Least Hazardous Medium	9
                                         Maximize Cleaning Efficiency	11
                                         Recycle and Reuse Waste	11

                               3.      Waste Minimization Approaches
                                      for Specific Classes of Cleaning Media	12
                                      Solvents	12
                                      3.1 Eliminate Need for Solvents	12
                                      3.2 Substitution Alternatives for Solvents	13
                                         Use Less Toxic Solvents	13
                                         Aqueous Cleaners	14
                                         Emulsion Cleaners	15
                                         Mechanical/Thermal Methods	16
                                      3.3 Minimize Solvent Losses	17
                                         General Options	17
                                         Cold Cleaning	20
                                         Vapor Degreasing	23
                                      3.4 Solvent Segregation and Recycle/Reuse	26
                                         Keep Solvents Segregated	26
                                         Recycling	27

 Waste   Minimization  i n  M e t a I  Parts  Cleaning  Operations
                                    Aqueous	31
                                    3.5 Substitution Alternatives for Aqueous Cleaners	31
                                    3.6 Use of Less Hazardous Compounds	31
                                    3.7 Maintain Solution Quality	31
                                        Precleaning Inspection	31
                                        Avoid Unnecessary Loading	32
                                        Provide Continuous Heating	32
                                        Proper Solution Make-Up	32
                                        Remove Sludge and Soils Promptly	33
                                        Monitor Cleaning Solution Strength	33
                                        Equipment Maintenance	33
                                        Reduce Drag-Out	34
                                        Increase Rinsing Efficiency	34
                                        Employ Closed Loop Systems	36
                                        Proper Parts Drying	36
                                    Abrasives	38
                                        Use of Greaseless or Water-Based Binders	38
                                        Use of Liquid Spray Compositions	38
                                        Control Water Level in Mass Finishing Equipment	38

                              4.     Implementation	39

                              5.     Conclusions	39

                              6.     Selected Bibliography	41

                              7.      Sources of Information on Waste Minimization	48

  Waste   Minimization  in  Metal Parts  Cleaning  Operation

          "The Congress hereby declares it to be the national policy of the United States that, whenever feasible,
       the generation of hazardous waste is to be reduced or eliminated as expeditiously as possible." HSWA 1984.
 The Hazardous and Solid Waste Amendments of 1984 to the Resource Conser-
 vation and Recovery Act (RCRA) establish as a national policy that hazardous
 wastes are to be reduced or eliminated as expeditiously as possible.  To help
 accomplish this goal, the U.S. Environmental Protection Agency (EPA) will
 provide technical materials and guidance  to companies through its waste
 minimization technology transfer program.  As part of EPA's program, this
 booklet was prepared to provide waste minimization options to companies
 with parts cleaning operations.

 Parts cleaning is an important process  for a large variety of organizations
 involved in the manufacture, repair, and maintenance of parts and equipment.
 From large metal fabrication plants to captive maintenance shops of industrial
 facilities, parts cleaning operations are essential to doing business.

 The reason for focusing  attention on minimizing waste in parts cleaning
 operations is because the solvents and other chemicals used in parts cleaning
 often result in significant air emissions, wastewater discharges, and the gen-
 eration of hazardous wastes. Waste minimization offers a significant and often
 cost effective opportunity to reduce the emissions and discharges of toxic pol-
 lutants into the environment.

 This booklet is organized as follows. This introduction covers basic definitions
 and concepts of waste minimization, and it outlines incentives for minimizing
 waste. A general strategy for minimizing waste is presented. An approach for
 applying this waste minimization strategy to parts cleaning operations is
 provided in Section Two, which begins with an overview of parts cleaning
 operations. Section Three presents waste minimization options in solvent
 cleaning, agueous-based  cleaning, and  abrasive cleaning applications.  A
 discussion of  options implementation follows; then conclusions, waste mini-
 mization information sources, and a bibliography close the document.

 This booklet is intended to provide the reader with key concepts and establish
 a good point of departure in the search for viable waste  minimization tech-
 niques. Examples are provided throughout the text to help the reader obtain
 more detail or specifics for an option being discussed. However, this booklet
 is not intended to replace in-depth references or provide detailed information
 that may be needed to fully evaluate the feasibility of a specific option.

 Where this information is available, the examples provided in this  booklet
 include the economics of implementing a waste minimization option. How-
 ever, the economics of making changes in an operation are often facility-
 specific; the scale of an operation may have a great deal to do with whether new
 capital outlays can be justified, for example. Because of differences between
facilities, generalizations are difficult and the reader is advised to consider site

  Waste   Minimization  in Metal  Parts  Cleaning  Operations
                                 specifics in determining whether a waste minimization option is economically
                                 feasible. In addition to the conventional capital and operating costs that are
                                 part of profitability analysis, waste minimization projects should; be consid-
                                 ered for their less tangible but beneficial consequences, such as avoided
                                 regulatory compliance costs, liability avoidance, improved health and envi-
                                 ronment and resulting improved public image. The reader is referred to EPA's
                                 Waste  Minimization  Benefits Manual for additional information (USEPA,
1.1 What is  Waste Minimization?
                                 Waste minimization can be accomplished either through source reduction or
                                 recycling of hazardous wastes that are generated or subsequently treated, dis-
                                 posed of, or stored (Figure 1). Although much of the current focus of waste
                                 minimization is on hazardous waste, EPA encourages and promotes the mini-
                                 mization of all wastes released into air, water, and land.

                                 Source reduction is the in-plant reduction of waste, usually and preferably
                                 within the process that generates it. Recycling is the use, reuse, or reclamation
                                 of waste material. Treatment of hazardous waste is not considered by EPA to
                                 be waste minimization, unless it is performed as a necessary step to render the
                                 waste recyclable.  The reduction of waste toxicity by dilution, or of waste
                                 volume by dewatering (or more generally, by the removal of an inert innocu-
                                 ous component) are not considered alone and by themselves to be viable waste
                                 minimization options.

                                 One approach to waste minimization is source reduction. The in-plant source
                                 reduction approach relies on changes to input materials, to the physical plant
                                 (or technology), or to the operating practices component of the manufacturing
                                 process. Of all three methods of source reduction, the improvement of oper-
                                 ating practices is often the easiest, least costly, and most effective waste mini-
                                 mization approach, especially in the initial stages of a waste minimization

                                 Source reduction is generally preferable to recycling because waste generation
                                 is directly  curtailed  or avoided in the first place.  Recycling  should be
                                 conducted wherever possible, for wastes that cannot be eliminated or reduced
                                 by making changes in the process.

 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
                Figure 1.   WASTE MINIMIZATION DEFINITIONS

   The elimination or reduction, to the extent feasible, of hazardous waste that is generated and would
   otherwise be subsequently treated, stored or disposed of.  It includes any source reduction or recycling
   activity undertaken by a generator that results in either (1) the reduction of total volume or quantity of
   hazardous waste or (2) the reduction of toxicity of the hazardous waste, or both, so long as such reduction
   is consistent with the goal of minimizing present and future threats to human health and the environment
   (USEPA 1986).


          Any activity that reduces or eliminates the generation of hazardous waste at the source, usually
          within a process (USEPA 1986).


          A material is "recycled" if it is used, reused, or reclaimed (40 CFR 261.1(c)(7). A material is "used
          or reused" if it is either (1) employed as an ingredient (including its use as an intermediate) to make
          a product; however a material will not satisfy this condition if distinct components of the material
          are  recovered as separate end products (as when metals  are recovered from metal containing
          secondary materials)  or (2) employed in a particular function as an effective substitute for a
          commercial product (40 CFR 261.1(c)(5).  A material is "reclaimed" if it is processed to recover a
          useful product or if it is regenerated.  Examples include the recovery of lead values from spent
          batteries and the regeneration of spent solvents (40 CFR 261.1(C)(4).
1.2 Incentives For Minimizing Waste
                               There are numerous economic, regulatory, legal, and other incentives for mini-
                               mizing waste. A summary of these incentives is provided in Table 1.

                               It is worth noting that, unlike traditional end-of-pipe treatment approaches,
                               waste minimization offers real potential for reducing manufacturing cost and
                               thus can successfully compete with other plant improvement projects for

 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
1.3 Waste Minimization Assessments
                               Specific waste minimization options can be identified and developed by
                               conducting a waste minimization assessment. The assessment process (Figure
                               2) is a set of procedures for investigating waste streams, generating waste mini-
                               mization options, evaluating their feasibility and implementing those that are
                               found to be feasible. The reader is referred to the EPA's Waste Minimization
                               Opportunity Assessment Manual (USEPA 1988B) for details on how to execute
                               the assessments and other components of the overall waste minimization
                               program. The most successful programs in industry include a strong manage-
                               ment and employee commitment to reduce waste and save money.
                     Table 1.  Incentives for Waste Minimization
          Increased land disposal costs.
          Savings in raw material and manufacturing costs.
          Avoidance of costly alternative treatment technologies.
          Certification of a waste minimization program on the hazardous waste manifest.
          Biennial waste minimization program reporting.
          Land disposal restrictions and bans.
          Increasing permitting requirements for waste handling and treatment.
          Potential reduction in generator liability for environmental problems at both onsite and offsite
          treatment, storage, and disposal facilities.
          Potential reduction in liability for worker safety.
   Public Image and Environmental Concern
          Improved image in the community and among employees.
          Reduced impact on the environment.
   Source:  USEPA, 1988B.

Waste     Minimization    in    Metal   Parts    Cleaning    Operations
Figure 2. The Waste Minimization Assessment Procedure

The Recognized Need to Minimize Waste
• Get management commitment
• Set overall assessment program goals
• Organize assessment team
Assessment Organization &
Commitment to Proceed
• Collect process and facility data
• Set priorities for assessment targets
• Review data and inspect site
• Develop options
• Screen & select options for detailed analysis
Assessment Report of
Selected^ Options
• Technical evaluation
• Economic evaluation
• Select options for implementation
Final Report, including
Recommenced Options
• Justify projects and obtain funding
• Installation (equipment)
• Implementation (procedure)
• Evaluate performance
Successfully Implemented
Waste Minimization Projects

Select New Assessment
Targets and Reevaluate
<- 	 Previous Options
	 ^ Repeat the Process

Waste  Minimization  in  Metal  Parts  Cleaning  Operations

2.1 Overview of Parts Cleaning.
Parts cleaning is an integral process operation for industries that repair,
maintain, or manufacture parts and equipment. Examples of such industries
are automobile repair, equipment repair, and transportation maintenance
industries (trucks, trains, ships, and aircraft). Manufacturing groups include
furniture manufacturers, metal fabricators, machinery manufacturers, elec-
tric and electronic equipment manufacturers, and instrument manufacturers,
among many others.

While the science of parts cleaning is very complex, the aim of cleaning is
relatively simple — to avoid the generation of rejects during subsequent use
or processing steps by removing contamination (i.e. soil) from the surface of
the parts being cleaned.  Removal of soils  can be achieved by way  of
detergency, solvency, chemical reaction, or mechanical action. Each of these
actions, or a combination of actions, can be employed in a cleaning operation.

Organic solvents, the most widely used class of cleaners, are used primarily
for removing organic  or oil-based contaminants.  The types of solvents
commonly used for commercial cleaning applications are shown in Table 2
along with other cleaning  media, listed by their cleaning action.  Table 3
provides a summary of cleaning methods or means of applying a particular
cleaning medium.

Aqueous cleaners  can contain acids,  alkalies or  chelating  agents.  Acid
cleaners such as sulfuric, nitric, and hydrochloric acids are used  to remove
oxidation scale and rust from metal surfaces. Alkaline cleaners are solutions
of inorganic salts often used in heated soak tanks to remove heavy oily soils
and some solid soils. Caustic solution is often employed as a paint stripping
agent.  For both acid and alkaline aqueous cleaners, rinse water plays an
important part in the cleaning operation.

Abrasives are designed to remove rust, oxides, and burrs to create a smooth
surface.  Common abrasives are sand, aluminum oxide, or silicon carbide
mixed with an oil- or water-based binder.

Detailed review and discussion of parts cleaning can be found in several
references  in the bibliography, including Spring, 1963 and 1974; Durney,
1984, and the American Society for Metals' Metals Handbook, 1988.

Waste   Minimization  in  Metal  Parts   Cleaning  Operations
                     Table 2.   Cleaning Media, Listed by Action

     (1) Alkaline salts and caustics
     (2) Surfactants (soaps and synthetic soaps)
     (3) Alkaline cleaners (1 and 2 combined)
     (4) Emulsion cleaners (solvents and surfactants)


     (1) Aliphatic hydrocarbons: naphtha, kerosene, diesel fuel
     (2) Aromatic hydrocarbons: benzene, toluene, xylene
     (3) Non-flammable solvents (halogenated hydrocarbons: TCA, TCE,
         PCE, methylene chloride, chlorofluorocarbons)
     (4) Polar solvents (ketones, alcohols, esters, ethers, terpenes, amines)
     (5) Emulsifiable solvents (flushed away with water)
     (6) Diphase cleaners (solvent and aqueous layered media)

  Chemical Reaction

     (1) Acidic baths (pickling) yield soluble salts by reaction with oxides,
         sulfides, etc.
         (a) Mineral acids: sulfuric, hydrochloric, phosphoric acids
         (b) Passivating acids:  nitric, chromic
         (c) Organic acids
         (d) Specialty acids containing surfactants for wetting-out action or a foam blanket or pickling
            inhibitors to prevent excessive attack on the metal
     (2) Alkaline baths
         (a) Alkaline de-rusters containing  organic sequestrants which solubilize metal oxides and also
            remove soils
         (b) Molten alkali with or without hydride (reductant) or nitrate (oxidant) or electric current; also
            removes soils
     (3) Chelating agents react with soils to  form soluble complexes
     (4) Electropolishing (reverse current cleaning), electrodissolution of
         metal substrate at the anode
     (5) Oxidizing or reducing agents to chemically render the soil soluble

 Mechanical Action

     (1) Turbulence/agitation
     (2) Abrasives
     (3) Deformation
     (4) Ultrasonic cleaning
     (5)  Heat
     (6)  Electrocleaning (direct current hydrogen scrubbing at the cathode)

 Source: Adapted from Spring,  1963.

 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
                                Table 3.   Cleaning Methods
  Wire brushing
  Grinding or machining
  Sandblasting or abrasive
  Shot blasting
  Liquid blasting
  Hydroblast with abrasives
  Blasting with softer
    material, e.g. plastic
    bead blasting
  Cryogenic paint stripping
  Physical distortion

  Molten salt bath

  Wipe on, wipe off

  Circulation of cleaner

  Air sparging (aqueous
    cleaners only)
Spray cleaning
Tumbling in barrels

Ultrasonic cleaning
Steam cleaning or stripping

Vapor degreasing
  (solvents only)

Electrocleaning (aqueous
  cleaners only)
Flame or hot air

Centrifugal wheel
2.2 Waste Minimization Strategy for Parts Cleaning
      Can cleaning be avoided?
The recommended strategy for developing effective waste minimization
options for parts cleaning operations relies on systematic exploration of the
following sequence of steps:

       1.      Avoid the need to clean.
       2.      Select the least hazardous medium for cleaning.
       3.      Maximize cleaning efficiency.
       4.      Segregate cleaning wastes.
       5.      Maximize recycling and reuse.

This strategy is consistent with the  multi-media approach and general
emphasis of reducing the waste at the source. Each step is discussed in the
following sections.

In many instances, by controlling  the factors  that contribute to surface
contamination of the parts, the need for cleaning can be reduced or eliminated
altogether. Control of part contamination starts with a study of contamina-
tion sources. Sources can be incoming soils applied by metal vendors or soils
applied in house (i.e., coolants, stamping fluids, drawing compounds, rust
inhibitor, etc.). Some frequently encountered sources and types of contami-
nation are shown in Table 4.

Waste   Minimization  in  Metal  Parts   Cleaning  Operations
                               Upon identifying the type and origin of the contamination, it is worthwhile
                               to examine whether cleaning can be avoided or its extent reduced.  For
                               example, protective coatings of grease or paint (which require solvents for
                               removal) can be replaced with peel coatings or shrink-wrapping of items with
                               polymeric sheeting. Moisture which can lead to rust can often be reduced or
                               eliminated by allowing the parts to dry more thoroughly between operations
                               or by storing them indoors to avoid condensation and/or rain.

                               Also of importance is the location of cleaning operations in manufacturing
                               sequence. Articles to be cleaned prior to finishing should only be cleaned at
                               the point in time when they are ready for coating. Parts should not be cleaned
                               and conversion-coated and then warehoused or staged for subsequent batch
                               coating. During storage, the parts can become contaminated by air-borne oils
                               or by handling. These contaminants will interfere with ultimate finish quality
                               and increase the rate of rejects.

                               Examination and subsequent control of contamination sources may lead to
                               reduction or  elimination of cleaning requirements, as  illustrated  above.
                               However, it is also important to note that an unwarranted relaxation of
                               cleaning requirements may  have an opposite effect of increasing waste
                               generation associated with rework of the rejects, e.g. due  to poor coating
                               quality.   Any proposed changes to the  cleaning process require careful
                               evaluation of potential waste generation in downstream operations.

              Select the least   The choice  of cleaning medium  for a given parts  cleaning  operation is
          hazardous medium   determined by a number of factors:

                                   •   physical and chemical properties of contaminants, substrate surface,
                                      and cleaning media.
                                      the amount of contaminant to be removed
                                      the required degree of cleanliness and product quality
                                      size, shape, and complexity of part to be cleaned
                                      volume or number of parts to be cleaned  per unit time
                                      costs of raw materials, equipment, and labor
                                      worker protection
                                      environmental protection
 Oil is often used to coat metal parts before shipment in order to prevent rust, which forms on exposure to air
 and moisture. Similar protection can be achieved by a removable plastic coating, such as polyethylene shrink-
 wrapping. At the receiving facility, the use of vapor degreasing to remove the oil is no longer necessary.

 Removal of oil contaminants prior to welding
 The welding  of metal parts which have residual oils present on or near the weld leads to the formation of
 carbonaceous deposits due to pyrolysis of organics at high temperatures. Such deposits are extremely difficult
 to remove. Cleaning the parts prior to welding greatly reduces the subsequent cleaning requirements.

 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
              Table 4.  Types and Sources of Surface Contamination

   Pigmented metal
   drawing compounds
   metal drawing
   Polishing and
   buffing compounds
   Cutting and
   Oxidation and
   Quenching oils

   Rust protection oils

   Lube oils and hydraulic

   Paint and inks





Oil with friction
reducing pigments
(talc, chalk,
lithopone, sulfur,
graphite or lime)

Mineral oils and
highly chlorinated
synthetic oils,
mineral oils and
greases, vegetable or
animal oil and/or
fats, aliphatic esters,
and emulsifiable
synthetic oils

Greases, metallic
soaps, abrasives
and waxes

Plain and sulfonated
mineral and fatty oils,
chlorinated mineral
oil soaps, salts and
saturated fatty alcohols

Rust (metal oxides),
heavy metal salts,
water scale'
Pigment with binder
Body oils,

Metal chips, dust,
carbonaceous deposits

Rosin, terpenic

Press and punch
Press forming,
bending (tubes)
Polishing and

Heat treatment

Surface protection,

Exposure to water,

Manual handling
Dusty environment,


Waste   Minimization  in  Metal  Parts   Cleaning  Operations
                                The relative importance of these factors can change considerably over time.
                                For example, both benzene and carbon tetrachloride (former standards in
                                industry) have been found to be carcinogenic and were regulated out of use
                                as metal cleaners because of heightened concern over worker exposure. This
                                same concern, and increased disposal costs, have caused some major automo-
                                tive manufacturers to phase out solvent cleaners in favor of aqueous cleaners.

                                In looking for a new cleaning medium or procedure, a company should
                                consider the least toxic or most environmentally acceptable medium, then, if
                                this is not satisfactory, progress to more toxic or less environmentally desir-
                                able alternatives. This pattern dictates that cleaning media be evaluated in
                                the following order:

                                       water or air
                                       abrasive media with water or air as carrier
                                       aqueous detergent solutions
                                       alkaline solutions

                                Ideally, the cleaning method of choice would involve the shortest cleaning
                                sequences, employing the least toxic cleaning medium, generating the least
                                amount of wastes, and still providing the necessary  minimum level  of
                                cleaning to the part at minimum cost. For facilities attempting to change from
                                one cleaning medium to another, the impact on subsequent operations must
                                be  considered.   Any proposed changes to  the cleaning process  requires
                                careful evaluation of potential effects of the cleaner on the substrate that
                                might affect the integrity of downstream processes (anodizing, plating, paint-
                                ing, etc.).  The impact of cleaner drag-out on  the lifespan of downstream
                                process solutions should also be addressed.

 Maximize cleaning efficiency   If a cleaning step cannot be eliminated, and the least hazardous cleaning
                                material that is effective is already being employed, then it should be used as
                                efficiently as possible. From a waste reduction point of view, this means using
                                the least amount of cleaning medium to achieve an acceptable level of
                                cleanliness. Examples of ways to improve cleaning efficiency are cited in later
                                sections of this booklet for solvent  cleaners, aqueous-based cleaners, and
                                abrasives, respectively.

      Recycle and reuse waste  The cleaning waste that cannot be eliminated through substitution or more
                               efficient use should be considered for recycling or reuse. The segregation of
                               different types of cleaning waste may be required for such recycling or reuse.
                               Specific examples of recycling and reuse are discussed for specific cleaning
                               media in later sections of this pamphlet.

 Waste  Minimization  in  Metal  Parts   Cleaning  Operations
                               In the following sections, waste minimization strategies that are effective for
                               specific cleaning media are presented. The order of presentation — solvents,
                               aqueous-based, and abrasive cleaners — reflects the need to replace or reduce
                               the use of the most hazardous materials first.  Also, a greater amount of
                               information is presented regarding ways to minimize solvent use than is
                               provided for aqueous or abrasive cleaners, since solvents are a greater concern
                               both environmentally and from a health standpoint.
Although organic solvents have excellent cleaning properties, many of them
are considered hazardous to human health and the environment. The negative
environmental and health-related attributes of solvents, particularly haloge-
nated ones include:

           ability to dissolve or penetrate polymeric landfill liners
           high diffusivity through porous strata
           ability to dissolve and serve as a carrier to other toxic organics
           high volatility
           photochemical reactivity
           long half-life
           toxic degradation products
           resistance to biodegradation
           depletion of stratospheric ozone

Solvent wastes were among the first to be banned from land disposal by EPA.
The 1984 RCRA amendments specify five categories of solvent waste (F-001 to
F-005) which are banned from land disposal effective November 1986 (RCRA
3004 (e)(l)). Due to the diverse problems associated with solvent use, solvents
should be used only when no other cleaner is suitable for the job. The major
ways to avoid or reduce the generation of solvent waste include eliminating the
need to use solvent; finding adequate  substitutes for solvents; minimizing
losses associated with solvent use; and segregation, recycle, and reuse of waste
3.1 Eliminate the Need for Solvents
                               The first priority in efforts to reduce solvent waste is to examine the cleaning
                               steps that require solvent. Such examination should aim to avoid solvent use
                               by eliminating or modifying the cleaning step. Special attention must be given
                               to the origin of soil and its composition.
 Eliminate cleaning step
 AT&TTechnologies, Inc. of Union, N. J., report that simple changes made in a testing operation enabled the com-
 pany to eliminate a cable-end cleaning step that had employed 1,1,1-trichloroethane (Waste Reduction-The
 Untold Story, 1985).

 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
3.2  Substitution Alternatives for Solvents
          Use less toxic solvents
Many firms have been successful in substituting less toxic cleaning media for
solvents. The alternatives include:

      •  substitution of toxic solvents with less toxic solvents
      •  substitution of solvents with aqueous cleaners
      •  substitution of solvents with emulsion cleaners
      •  substitution of solvents with mechanical and/or thermal methods

Discussion of each substitution approach is provided below. Most emphasis
is given to  aqueous cleaners, since this is the major and often most effective

In the case of halogenated solvents, media substitution will often require a
switch from vapor degreasing to cold tank cleaning with possible addition of
mechanical or ultrasonic agitation, A preliminary analysis of possible substi-
tutes for chlorinated solvents is available (US EPA 1983).

Substituting one solvent for another in cleaning applications has an extensive
history. Trichloroethylene (TCE) is being replaced by 1,1,1-trichloroethane
(TCA). Benzene and other toxic aromatic solvents were replaced by less toxic
aliphatic solvents such as Stoddard solvent and naphthas. Possible solvent
alternatives to halogenated compounds include:

      •  aliphatic hydrocarbons  (e.g. naphthas)
      •  terpenes
      •  N-methyl-2-pyrrolidone
      •  dibasic acid esters

Although photochemically reactive, terpenes (derived from citrus plants and
pine trees) are  "generally recognized as safe" substances  (Hayes, 1988).
However, carcinogenicity of terpenes and other cycloalkenes has not been well
explored. The terpene cleaners are available commercially in neat form or as
water solutions with surfactants, emulsifiers, rust inhibitors, and other addi-
tives. Terpenes tested very favorably as substitutes for halogenated solvents
for removal of heavy greases, oily deposits, and carbonized oils. Terpenes are
being actively tested as alternatives to chlorofluorocarbons in electronic parts

Reported disadvantages of terpenes include inability to separate long chain
aliphatic oils  for recycle of the cleaning solution both in neat form and in
aqueous emulsions. Ultrafiltration to remove oil is not viable for recycle and
is only useful for treating dilute  emulsions prior to wastewater treatment.
Recovery by distillation is impractical since terpenes boil around 340°F, which
means that many light oils would be carried over with the solvent.  Energy cost
for distillation recovery, even with vacuum assist, would be high. Difficulties
in rinsing residues from parts surfaces have been cited.  Also, terpenes cost
three to five times more than traditional chlorinated and hydrocarbon sol-
vents.  (Evanoff, 1988).

 Waste   Minimization   in  Metal  Parts  Cleaning  Operations
Other substitutes for halogenated solvents include N-methyl-2-pyrrolidone
(Taylor 1988), and dibasic acid esters (Lucas 1988).  These substitutes are
considered to be safer and environmentally preferable to halogenated solvents
due to their low volatility and biodegradability.  For additional information,
the reader should contact manufacturers of these products directly.  It is
recommended that sol vent/cleaner recyclability be thoroughly investigated
along with cleaning properties, volatility, toxicity, cost, and other attributes.
              Aqueous cleaners  Historically, aqueous cleaners have been used extensively throughout the
                                industry. In recent years, their use has increased as environmental concerns
                                and regulatory restrictions placed solvent cleaners under more scrutiny.

                                The simplest aqueous cleaner is water, which can be used in conjunction with
                                mechanical or ultrasonic agitation. Hot water high pressure spray systems are
                                quite effective  at removing caked-on dirt and grime.  Where hard water
                                deposits may result in staining, use of demineralized or deionized water is
                                recommended. Use of demineralized water in a reuse bath preceding a plating
                                or process bath can  help avoid the build-up of calcium and magnesium
                                contaminants in the bath. For example, hot deionized water has been success-
                                fully tested as a replacement for CFC-113 in certain critical cleaning applica-
                                tions hi the manufacture of disk drives in the electronic industry.

                                The cleaning action of aqueous cleaners relies mainly on displacement of soils
                                rather than dissolving them as is the case with organic solvent. Two classes of
                                aqueous cleaners, alkaline and acidic cleaners, are usually distinguished based
                                on pH.  Application methods  include soak  cleaning, spraying, ultrasonic
                                cleaning, electrocleaning, and steam cleaning.

                                Alkaline cleaning solutions contain builders (sodium salts of phosphates,
                                carbonates, silicates, and hydroxides) and surfactants (detergents and soaps).
                                Other additives may include anti-oxidants and stabilizers as well as small
                                amounts of solvents. Acidic cleaning solutions may contain mineral acids
                                (nitric, sulfuric, phosphoric, or hydrochloric), organic acids (sulfamic, acetic,
                                oxalic, or citric), detergents, chelating agents, and occasionally small amounts
                                of solvents.
 Use ivater in place of solvents
 Certain electronic filter circuits are housed in aluminum casings. The casings are manufactured by an outside
 sheet metal contractor who cleans the parts prior to shipment. Since delivered parts had occasional visible stains,
 methyl alcohol was used to remove them. A simple investigation showed that hot deionized water was equally
 effective (SFE, 1985).

 Replace solvent with aqueous cleaning medium
 An electronic manufacturing facility of a large corporation originally cleaned printed circuit boards with
 solvents.  The company found that by switching from a solvent-based cleaning system to an aqueous-based
 system the same operating conditions and workloads could be maintained. The aqueous-based system cleaned
 6 times more effectively. This resulted in a lower product reject rate, and eliminated a hazardous waste (USEPA,

 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
             Emulsion cleaners
It is important to evaluate the wastewater quality issues and recyclability
aspects when selecting an aqueous cleaner.   Generally, selection of non-
emulsifying cleaners which promote oil separation will enhance recyclability.
Process equipment involves a heated tank equipped with oil skimmer and
mechanical agitation, spraying, or ultrasonic devices. The cleaning step is
usually followed by water rinsing and air drying.

Quite often, solvent is employed for cleaning because an attempt to utilize an
aqueous cleaner was unsuccessful. Before committing to solvent, one should
investigate the compounds requiring removal. High melting temperature
compounds are often  used in forming compounds, lubricants and preserva-
tives, making removal with aqueous cleaners  difficult.  Suppliers of metal
processing chemicals  can recommend substitutes that can be cleaned with
aqueous cleaners thus eliminating solvent and emulsion cleaners. General
studies are available (Briggs, 1976; Wagner, 1984; USEPA, 1983; Evanoff, 1988);
however, each application is highly specific and generalizations are difficult.
Testing of a number of potential substitutes is recommended (see Table 5). The
reader is advised to contact aqueous cleaner manufacturers for specific recom-
mendations.  A comprehensive list of manufacturers and trade names can be
found in recent issues of Metal Finishing's "Guidebook & Directory" or other
standard buying guides.

Emulsion cleaners combine solvent cleaning with aqueous cleaning so that
water-immiscible solvent is dispersed in the aqueous phase with the aid of
emulsifiers, surfactants, and coupling agents.  The large surface area of the
dispersed solvent phase often allows the attainment of results achievable with
direct solvent cleaner. Solvent vapor pressure and evaporation losses  are

Emulsion cleaners are used for immersion or spray cleaning  in cold  baths
predominantly in metal fabrication facilities. Disadvantages include residual
oil film on the parts (which necessitates an additional cleaning step in applica-
tions where a high degree of cleanliness is required), relatively low saturation
capacity, and difficulties in recycling by separation of oil and reconstituting the
cleaner. Emulsion cleaning is no longer a widespread technology and is being
quickly replaced by aqueous cleaners.  For more information on emulsion
cleaners, the reader is referred to USEPA, 1983.
Replace solvent with alkaline cleaning media
 The Torrington Company in Walhalla, S.C, was using vapor degreasers containing 1,1,1-TCE to clean metal
bearings for the automotive industry. Because of concern about worker health and increasing solvent prices, the
company installed an alkaline degreaser that employed a two-stage washer and hot air drier. The waste water
from this system can be discharged directly to the sewer system because the alkaline cleaner is considered non-
hazardous (Kohl,  1984).

Reduction of solvent use
 A company that reduced TCE use is the Hamilton Beach Division of Scovill, Inc. in Clinton, N.C., which
manufactures small electric appliances. Scovill found that a water-soluble synthetic cleaner manufactured by
Cincinnati Milacron Co. could  be used in place of the TCE organic solvent degreaser  for some applications,
reducing TCE use overall by 30 percent. This saved $12,000 per year. (Huising, et al. 1985).

Waste  Minimization  in  Metal  Parts   Cleaning  Operations

  Mechanical/thermal methods In addition to aqueous cleaners, mechanical and/or thermal methods are quite
                               effective at eliminating the need for solvents. Solvents are often used to dry
                               parts following a water rinse operation. As an alternative, air blast systems
                               utilize a high velocity air jet that blows water droplets and other contaminants
                               from glass, metal, or wood parts. Abrasive blast cleaning methods use a plastic
                               blast media  to clean and strip parts. Dry stripping and cleaning can reduce
                               disposal costs and water usage and have been shown to reduce labor costs
                               significantly. The plastic media are recycled.
                      Table 5.  Selection of an Aqueous Cleaner1
          1.      Review cleaner composition. Hazardous or undesirable components are identified on
                 material safety data sheets. Many candidate cleaners can be eliminated on this basis.

          2.      Identify contaminants to be cleaned from parts, and obtain samples of each.

          3.      Apply each contaminant to representative metal panels and immerse in each candidate
                 cleaner in laboratory scale cleaning tanks. Use manufacturer's recommendations for
                 concentration and temperature, and provide mechanical agitation. After periods of 5,10,
                 and 15 minutes, remove panels from bath, rinse, and evaluate cleanliness.  Cleanliness
                 can be ascertained by (a) water break, (b) fluorescence under UV light (applicable for
                 soils that fluoresce), and (c) by immersing in a cupric chloride solution and observing
                 uniformity of copper deposited.

          4.      If a contaminant was cleaned (from Step 3), lower the temperature and re-test until the
                 minimum effective temperature is identified. Also determine the minimum effective
                 cleaner concentration in a similar manner.  If the contaminant from Step 3  was not
                 cleaned, increase temperatures and concentrations to identify minimum effective para-
                 meters.  These data will permit selecting the optimum operating conditions for any
                 contaminant or mixtures thereof of any of the cleaners evaluated.

          5.      Using a series of standard tests, determine etch rates, staining characteristics, effects on
                 coatings' adhesion, and corrosion characteristics.

          6.      Evaluate cleaner performance including tank maintenance, recyclability, and disposal re-
                 quirements in a pilot plant-scale tank prior to full scale implementation.

   ; Selection process developed by General Dynamics/Fort Worth Division (Evanoff et al 1987).
 Abrasive substitutes for solvents in paint stripping
 Conventional paint stripping of aircraft may use 8,000 gallons per aircraft of such solvents as methylene chloride
 or hot caustic.  Hill Air Force Base in Ogden, Utah, has successfully employed plastic beads propelled by high
 pressure air j'ets (bead blasting) to remove paint from aircraft exteriors. Besides not generating hazardous waste,
 the use of bead blasting improved personnel working conditions, was easier to perform than solvent paint
 stripping, and cost less and used less raw material.

 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
To replace the use of chlorinated solvents in paint stripping operations, heat or
flame cleaning ovens are becoming more common. Heat cleaning ovens burn
off paint and other organic compounds from metal parts. Specifically, these
techniques have been successful in cleaning paint hangers and hooks. A dis-
advantage of heat cleaning ovens is the production of combustion emissions.
3.3  Minimize Solvent Losses •
                                Once it has been determined that the use of solvent cannot be avoided, all
                                efforts to reduce solvent use in a facility should be made. The following options
                                are grouped according to their application (general, cold cleaning, and vapor

               General options  Waste minimization options that apply to solvent use in general are discussed
                                below. These options include standardizing solvent use, consolidating solvent
                                cleaning operations, maintaining solvent quality, increasing cleaning effi-
                                ciency, and reducing solvent evaporation.

                                Standardize solvent use

                                Standardization means using the least number of different solvents in the
                                facility. A reduced inventory helps track solvent consumption, reduces the
                                risk of cross contamination, and eases waste handling. In addition to simpli-
                                fying cleaning operations, standardization also helps promote the potential for
                                downgrading or recycling waste solvents. Using fresh solvent for the most
                                critical cleaning applications  and reusing solvent sequentially for less de-
                                manding cleaning operations can reduce  overall solvent consumption and
                                waste production.

                                Consolidate cleaning operations into one centralized degreasing operation

                                Centralization helps in the effort to standardize solvent use.  It also eases the
                                effort it would take to supply many  solvent users dispersed throughout a
                                facility.  A centrally-located solvent issue and waste collection station was
                                found to be useful in solvent control and in proper waste handling in the multi-
                                user facility (SFE Technologies, 1985).

                                Maintain solvent quality

                                By maintaining solvent quality, the need for solvent replacement and disposal
                                is reduced.  Ways to  achieve this goal include contamination avoidance,
                                equipment maintenance, solvent monitoring, proper solvent addition, and
                                prompt sludge removal.  These approaches are discussed below.
Staged solvent use and standardization of solvent
A Massachusetts electronics firm switched from using three different solvents — mineral spirits for degreasing
machine parts, perchloroethylene for computer housings, and a fluorocarbon-methanol blend for printed circuit
boards — to a single solvent mixture. The mixture of 1,1,1-trichloroethane and alcohol is used for all three
applications in a staged system. Fresh solvent is used for the printed circuit boards, then is reused to degrease
the computer  housings and, last, the machine parts. Besides reducing solvent consumption and waste, this
practice has eliminated potential cross contamination of solvents, generated a single waste stream that can be
recycled, simplified safety and operating procedures, and increased purchasing leverage (Traverse, 1984).


 Waste   Minimization  in  Metal  Parts  Cleaning  Operations

Contamination avoidance
Parts should be checked for undue contamination, including moisture, before
being cleaned. Often, parts stored outside will pick up a large amount of con-
densation.  The introduction of water from condensation into a bath of
chlorinated solvent can acidify the solvent. When this occurs, the solvent must
be replaced and all equipment in contact with the solvent thoroughly flushed
and rinsed. Another problem is that water contamination can lead to increased
air emissions because of azeotrope formation. To avoid this problem, the parts
should be stored indoors. Precleaning inspections can help point out potential
problems that are due to upstream operations.

Another purpose of precleaning inspections is to promote workload segrega-
tion. In some situations, a given bath of solvent is more than adequate for
cleaning the normal  production workload but it fails to thoroughly  clean
heavily  soiled pieces. As these pieces pass  through production and  yield
rejects, the solvent bath is blamed for inadequate cleaning. Rather than having
to replace the bath due to an occasional heavily soiled object, it is better to
segregate these objects and to preclean or spot-clean them before the bath.

Material and/or process substitution can be another effective way of avoiding
undue bath contamination. Use of newer, water emulsifiable metal forming
lubricants that require less material, and spray/mist application devices will
minimize the amount of material applied (Evanoff, 1988).

Equipment maintenance
Racks and barrels should be maintained so as not  to introduce corrosion
products (such as rust) into the solvent. Corroded racks can also remove liquid
from the bath by way of capillary action.

Solvent monitoring
The  military is currently developing solvent test kits (Joshi et al, 1988) for
cleaning operations using Stoddard solvent (PD-680) and chlorinated solvents
(1,1,1 trichloroethane, methylene  chloride, trichloroethylene, and  perchlo-
roethylene). The purpose of these kits is to provide operators with simple,
reliable  and repeatable testing means for determining when solvent is spent.
Due to the often arbitrary nature in which the need for solvent replacement is
now determined, much solvent may be disposed of prematurely. The most
reliable  tests developed to date include light transmittance @ SOOnm, electrical
conductivity, and specific gravity for PD-680 and acid acceptance value, light
transmittance, and electrical conductivity for the chlorinated solvents.

Waste   Minimization  in  Metal  Parts  Cleaning  Operations
After establishing a proper monitoring program, work should be undertaken
to correct identified  problems.  Chlorinated solvents contain stabilizers to
prevent acid forming reactions with water, metal, heat, and oil. When an acid
acceptance test indicates that the solvent is near the point of "going acid," the
solvent is either disposed of or fresh solvent is added in an attempt to boost
stabilizer levels. Addition of fresh solvent is a poor solution since it results in
the degradation of the fresh solvent. A better solution is to analyze the solvent
and add only the specific components required (see example below). Since
each type of solvent may employ a different mix of stabilizers, the solvent
manufacturer should be contacted before any additions are made.

Careful solvent addition
Care should be taken whenever solvent is added to the tank to ensure that
proper solvent is being added. For example, as little as 0.1% TCA mistakenly
added to a tank of TCE can cause an acid condition requiring disposal of the
entire contents.

Sludge removal
Metal fines can catalyze reactions that lead to decomposition of the solvent.
Paint chips can absorb solvent and swell, forming a viscous sludge. Routine
maintenance should be performed to remove sludge. Continuous filtering is
often helpful.

Increased cleaning efficiency

As the level of contamination increases, the rate of solvency  slows  down.
While cold cleaning operations can be successfully performed at up to 10%
contamination, solvent baths are often replaced due to slow cleaning action,
when the contamination level reaches 2 to 3%.  A simple way to increase
cleaning  efficiency is to employ manual brushing.  Manual brushing is  ex-
tremely effective at removing caked-on soils and is a very common precleaning
technique. Disadvantages include exposure of workers to solvents, high labor
costs, and  the need  for high ventilation rates to protect workers.  High
ventilation rates can, in turn, lead to excessive solvent evaporation.
Maintaining solvent quality
The Ogden Air Logistic Center generates about 6500 gallons of waste 1,1,1 trichloroethane (TCA) from 21 va-
por degreasing operations. In an effort to reduce this waste, the chemical laboratory personnel determined that
the TCA was being disposed of because it did not meet an acid acceptance value of 0.10 weight percent NaOH.
Oil contamination levels were less than 10 percent at the time of disposal, far less than the expected 30 percent
level. To restore acid acceptance levels, 1,2 butylene oxide was added to the solvent. No adverse reactions or
detectable problems were observed when the butylene oxide was added to the vapor degreasers. Ogden Air
Logistics Center expects to reduce disposal volumes by 4000 gallons (60 percent) and save $30,000 per year
(Christensen, 1988).

 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
                              Cleaning efficiency can also be increased by increasing the degree of agitation
                              in the bath. Methods include use of mechanical agitators, ultrasonic devices,
                              liquid sprays, and liquid jet pump-around arrangements. Great care should be
                              taken with these methods to ensure that undue splashing does not occur.
                              Systems are available that provide a raising and lowering (or pumping) action
                              of the parts trays inside the bath while the unit is closed. Increased temperature
                              maybe employed to increase cleaning efficiency but this method leads to larger
                              evaporative losses.

                              Cleaning speed can be maintained effectively at high contamination levels
                              using ultrasonic agitation.   High frequency sound waves are transmitted
                              through the solvent, causing formation and collapse of small vapor bubbles at
                              solid surface (micro-cavitation).  The agitation assists in the removal of
                              insoluble soils. This supplementary cleaning action is not expensive, and it can
                              prevent the need for hand cleaning and reduce the number of rejects. Ultra-
                              sonic transducers may be added to existing equipment, and they can be used
                              in both vapor degreaser and cold cleaning applications.

                              Control of evaporative losses

                              The first step in controlling evaporative losses is the selection of the proper
                              location for cleaning operations. The area should be free from drafts and away
                              from any heat source, which can cause large evaporative losses. These large
                              losses can result in problems elsewhere in a facility.

                              The second step in controlling evaporative losses is through the proper use of
                              lids. Tank lids, even on cold tanks, are very effective in reducing solvent loss.
                              For vapor degreasers, roll-type covers are recommended over hinged covers
                              because they are less disturbing to the vapor zone.

                              Other methods that are effective in controlling evaporative emissions from all
                              solvent cleaning operations are the proper monitoring of temperature (if the
                              solvent is heated) and avoiding the use of porous items such as ropes or bags
                              for handling parts. Additional air emission control methods are discussed in
                              the subsequent sections.

                Cold cleaning Of the total number of cold cleaner soak tanks in use, it has been estimated that
                              70 percent are used for maintenance operations. Typically, most tanks hold 30
                              or more gallons of solvent and have about four square feet of open area. Cold
                              tanks used in manufacturing operations range from desktop sized units used
                              for cleaning small parts to units designed to clean large sections of aircraft.
                              Maintenance cleaning usually employs mineral spirits (petroleum distillates
                              such as Stoddard solvent) while manufacturing operations employ a wider
                              variety of solvents.

Locate solvent tank properly
One manufacturer placed a tank of chlorinated solvent near his paint cure oven. Heat from the oven caused
excessive emissions which were picked up by the oven's combustion fan. The emissions were burned, forming
hydrochloric acid, which ruined the finish on the painted parts in the oven. The manufacturer had to strip, clean,
and repaint all of the parts. All of the waste (not to mention the cost) associated with this event could have been
avoided if the tank was properly located (Durney, 1984).

Waste   Minimization  in  Metal  Parts  Cleaning  Op.erations
Some waste minimization options specific to cold cleaning soak tank opera-
tions include reducing the degree of drag-out and using a counter-current
cleaning arrangement. In addition to these methods, the reader should review
all of the general options discussed in the preceding section.

Reduce drag-out

Drag-out is the term applied to the liquid that comes along on the part as it is
removed from the tank. Excessive drag-out can result in increased solvent
replenishment costs, increased air emissions, and upset of downstream proc-
esses.  Methods for  reducing drag-out include proper racking, increased
drainage, and installation of drain boards.

Proper racking
Careful attention should be given to the design of work baskets and to methods
of racking so as to ensure that a minimum amount of solvent will be trapped
either in the work or in the baskets (Figure 3).
                     Figure 3.  Racking For Maximum Drainage

 Waste  Minimization  in  Metal  Parts  Cleaning  Operations
                              Increase drainage
                              Parts should always be allowed to drain inside the tank before being removed.
                              The installation of a rest shelf inside the tank allows the operator to better drain
                              the parts, especially heavy ones.  Depending on the size, shape, and function
                              of the part, some fabricators design the part to include inconspicuous drainage

                              Install drain boards
                              Drain boards are often helpful in recovering solvent that drips from a part.
                              Drain boards which extend from one tank to the next help to keep the area
                              between tanks  clean (Figure 4).

                              Use counter-current cleaning

                              Parts should be passed through a series of cleaning tanks or compartments.
                              The first tank consists of used solvent, the last rinse consists of very clean
                              solvent. When the first tank of solvent is spent, it can be pumped out for
                              disposal and each subsequent tank pumped into the previous tank. For
                              facilities with limited space,  existing tanks can be segmented.  Staging will
                              reduce the amount of solvent use by maintaining solvent quality for a longer
  Figure 4.  Installing Drain Boards Conserves Solvent, Keeps Floor Clean.
              Without Drain Board
With Drain Board
                                              •: w/ss/s/s/z/ww/w//////?//?/^^^

Waste   Minimization  in  Metal  Parts  Cleaning  Operations
Vapor degreasing  In industries that perform a large amount of cleaning, vapor degreasing
                  systems are common. Available sizes for open-top units range from 1x2 feet,
                  up to 6 x 100 feet. The typical unit size is approximately 3x6 feet. Open-top
                  units are commonly employed in the electroplating and electronics industries
                  where easily handled parts are cleaned. Conveyorized (or fully automated)
                  units are more common in the aerospace and large appliance product coating

                  Vapor degreasing systems usually consist of a tank of halogenated solvent that
                  is heated to the solvent's boiling point. Parts to be cleaned are placed in a basket
                  or on a rack and lowered into the vapor zone. As the solvent condenses, the
                  contamination is dissolved and the parts are rinsed and cleaned. To increase
                  cleaning efficiency, the parts may be immersed into the solvent bath or a
                  solvent spray unit may be employed. When the temperature of the parts finally
                  reaches  the temperature of the solvent vapor, condensation of the vapor onto
                  the part ceases. The parts can then be removed from the unit clean and dry.

                  Solvent use in vapor degreasing can be minimized by many of the general
                  options  discussed previously and by the options listed below:

                  Limit entrance/exit speeds

                  Solution and vapors are removed from the tank when a part is inserted or
                  withdrawn too quickly. Avoid speeds greater than 11 feet per minute to limit
                  excessive dragout.

                  Limit workload size

                  The use of baskets having an area of less than 50% of the degreaser opening
                  will limit vapor dragout due to piston effect (Figure 5).

                  Avoid work shock
                  Work shock occurs when a heavy load is introduced  into the degreaser,
                  resulting in collapse of the vapor blanket and infiltration of air into the cleaning
                  unit (Figure 6). The solvent-saturated air will be expelled from the unit when
                  the vapor layer is reestablished.

                  Maintain temperature of solvent

                  The temperature of the solvent in the degreaser should be maintained at a level
                  adequate for vapor production, to ensure that the degreaser functions effi-

                  Allow sufficient time in the degreaser

                  Ensure that parts have reached the temperature of the vapor so that conden-
                  sation has ceased.

  Waste   Minimization  in  Metal  Parts  Cleaning  Operations

                                    Figure 5. Piston Effect
                              Wide Workload
Wide Workload
                                Spray only below the vapor zone

                                The spray pattern should be a solid stream, not a fine mist.

                                Maintain proper solvent level in sump

                                In addition to excessive water contamination, a major cause of chlorinated
                                solvents going acidic is exposure of the heating coils to the solvent vapor.
                                Exposure causes localized overheating which results in decomposition of the
                                solvent. These items can be kept in check by inspecting the parts for excessive
                                water and by regularly checking the operation of the water separator and
                                solvent level controls.

                                Minimize vapor diffusion

                                Vapor  diffusion, which results in air emissions, can be reduced through
                                the following means:

                                    •  Check parts for excessive water contamination.

                                    •  Cover water separator to prevent vapor loss.

                                    •  Check water jacket for proper water flow and temperature on outside
                                       of degreaser.

Waste   Minimization  in  Metal  Parts  Cleaning  Operations
                                  Figure 6.  Work Shock
            A 1.  Work introduced
               2.  Rapid condensation on work
               3.  Vapor blanket collapses
               4.  Air pulled in
                      B 5.  Condensation on work stops
                         6.  Vapor blanket re-established
                         7.  Vapor-laden air expelled
    •  Extend freeboard. Increasing the freeboard/width ratio of a vapor
       degreaser can reduce solvent air emissions (see Figure 7).

    •  Use cold traps above freeboard chillers.

    •  Locate the degreaser away from drafts or use baffles to prevent upset
       of the vapors. Proper location can reduce solvent loss by 30 percent.

For additional information on ways to reduce emissions associated with vapor
degreasing, the reader should contact the solvent supplier.  Most if not all of
the major chlorinated solvent manufacturers have information available on the
proper way to utilize, maintain, and eventually dispose of their products.

 Waste   Minimization  in Metal  Parts  Cleaning  Operations
      Figure 7.  Effect of Changes in Freeboard/Width Ratio  (Figur
                                 EFFECT OF FREEBOARD/WIDTH RATIO AND
                                  FROM IDLING DEGREASER CONTAINING
                     o   o OT

                     i   1
                     3 a: a „,

                     o B g
                     in g z wo
                     O Q ui
                     _J (^j Q
                     O < 2
                     i- O O w
                     UJ CQ CJ
                     — tlj ^
                     t; o* <
                     3!tQ "°
                     [jj -L, 2

                     W ^ "^ .™
                     S   3-

                     *   |«

                         d. n
                                           Ratio = 0.46
                                                     Ratio = 0.75
                                                             Ratio = 1.0
                                        30    40    50    60    70    80
                                     AVERAGE CONDENSER TEMPERATURE °F
3.4  Solvent Segregation and Recycling/Reuse
                         In addition to the savings in solvent that result from minimizing losses during
                         use, overall solvent consumption can be reduced by segregating solvent
                         wastes and recycling or reusing them.  EPA estimates that up to 50% of all
                         solvent wastes are currently being segregated and managed for energy recov-
                         ery, reclamation or recycling.

                         To simplify waste solvent handling and to make recycling feasible, the follow-
                         ing procedures should be followed (Kohl, 1984 and California DHS, 1986):

Keep solvents segregated  In the recycling process, it is much easier to separate a solvent from its
                         impurities than to separate two solvents. Specific recommendations are
                         always to segregate:

                             •   Chlorinated from non-chlorinated solvent wastes.
                             •   Aliphatic from aromatic solvent wastes.
                             •   Freon from methylene chloride.
                             •   Water waste from flammable waste.

W a s  t e   M inimization  in  M e  t a I  Parts  Cleaning  Operations

           Keep waste solvents as free from water, solids, and garbage as possible

           Label the container clearly, keep the container closed and, if possible, sheltered
           from rain.  Drums should be covered to prevent contamination with water.

           Label the chemical content on each waste container

           Record the exact composition and method by which the solvent waste was

Recycling  Where recycling of solvent waste is viable, the choice between on-site versus
           off-site recycling must be made. Major factors that may influence a decision are
           shown in Table 6.
               Table 6.   Factors Influencing the Decision to Recycle
                                  Solvent Wastes on Site

  Less waste leaving the facility.

  Owner's control of reclaimed solvent's purity.

  Reduced liability and cost of transporting waste

  Reduced reporting (manifesting).

  Possible lower unit cost of reclaimed solvent.

  Perceived  Benefits

  Favorable economics for recovery
  (e.g. reduced solvent requirements).

  Reduction in disposal costs.

  Reduction in reporting (manifesting)

  Lower liability.

  Source:  California DHS, 1986.

                              Capital outlay for recycling equipment.

                              Liabilities for worker health, fires, explosions, leaks,
                              spills, and other risks as a result of improper equip-
                              ment operation.

                              Possible need for operator training.

                              Additional operating and maintenance costs.

                              Reported  Difficulties

                              Loss of solvent during distillation process.

                              Low solvent recovery efficiency.

                              Installation problems.

                              Maintenance problems.

Waste   Minimization  in  Metal  Parts  Cleaning  Operations
On-Site Recycling

On-site recycling is economical when approximately 8 gallons of solvent waste
is generated per day (Schwartz, 1986). The simplest form of solvent reuse is
termed "downgrading," which is the use of a solvent that has become contami-
nated through initial use for a second cleaning process. For example, precision
bearings need very high purity solvents for cleaning. The solvent acquires very
little contamination in usage and can be downgraded or used for less demand-
ing cleaning operations.

More effort is required to recycle solvent that has become heavily contami-
nated, and the possibilities for both on-site and off-site recycling or reclamation
need to be explored. In vapor degreasing and cold cleaning, the soil removed
accumulates in the equipment.  Eventually the solvent becomes too contami-
nated for further use and it must be reclaimed or disposed of via incineration.
For on-site recycling, many different separation technologies are available.
Commonly used separation technologies for contaminated solvents include
gravity separation, filtration, bath distillation, fractional distillation, evapora-
tion, and fuel use.

Gravity separation
The use of settling to separate solids and water from solvent often permits the
reuse of solvent. For example, paint thinners may be reused many times if
solids are allowed to settle out.

Filters  can be used to remove  solids from many solvents thus extending
solvent life.

Batch distillation
A batch still vaporizes the used solvent and condenses the overhead vapors in
a separate vessel. Solids or  high boiling residues (>400° F) remain in the still
as a residue. Solvent stills range in size from 5 gallon to 500 gallon capacity. A
vapor degreaser can be used as a batch still for recycling solvent. This is often
done by employing proper boil-down  procedures. Detailed discussion of
these procedures is available from major solvent suppliers.

In many applications, it is necessary to keep the water content of the recovered
solvent to less than 100 ppm. This can often be accomplished by distilling off
the solvent-water azeotrope, decanting the water, and then drying the remain-
ing solvent with a molecular sieve, or other desiccant. The water removed in
this operation must then be either treated or drummed for disposal.
 On-site recycling
 A company that used trichloroethylene in degreasing was able to cut its solvent waste from 20 drums a month
 to five drums a month—a 75 percent reduction. Virgin solvent consumption was reduced by 15 drums a month.
 Formerly, the company removed solvent waste from degreasers into a storage tank every other day. The stored
 waste was transferred to drums for disposal. Now, the solvent waste is pumped into a holding tank; every two
 weeks this collected waste is redistilled to recover as much solvent as possible, leaving only 5 drums per month
 requiring off-site disposal (USEPA1988 A).

Waste   Minimization  in  Metal  Parts  Cleaning  Operations
(For a survey of small still manufacturers and other technical information, the
reader is referred to "Guide to Solvent Waste Reduction Alternatives" avail-
able from the State of California Department of Health Services (Calif. DHS,

Fractional distillation
Fractional distillation is carried out in a refluxed column equipped with either
trays or packing.  Heat is supplied by a reboiler located at the bottom of the
column while heat is removed at the top of the column by a condenser.
Fractional distillation allows for separation of multi-component mixtures or
mixtures of solvent and oils with very similar boiling points.

Evaporation  can  be  employed for solvent recovery from viscous liquids,
sludges, or still bottoms resulting from distillation.  Scraped or wiped-film
evaporators utilize revolving blades which spread the liquid against a heated
metal surface. The vapors are recovered by means of a condenser. Another
type of system, a drum dryer, employs two heated  counter-rotating drums
through which the liquid feed must pass.  While both systems can handle
viscous  wastes,  the drum  dryer  is  more  tolerant of polymerizable

Off-Site Recycling

If recycling of waste solvent on site is impractical, several off-site recycling
schemes are available. One should consider or investigate all of the items listed
in Table 7 when selecting an off-site recycling scheme. Some  viable off-site
Recycling solvents efficiently
Segregating solvent wastes is usually an essential step prior to recycling. IBM Corporation reported that
segregation may also increase recycling efficiency; segregating non-chlorinated from chlorinated solvents
resulted in 15 to 20 percent greater yields (Waste Reduction - The Untold Story, 1985).

Mobile solvent degreasing units
Automobile repair shops in California can lease fully-contained degreasing systems from Safety Kleen Inc.
Safety Kleen provides a batch-tolling service for degreasing solvents; it leases its mobile units, including
solvents, as one system. Safety Kleen periodically replaces the spent solvent with fresh solvent, and recycles the
spent solvent at a separate facility.

Waste exchanges
Waste exchanges  generally exchange some 20 to 30 percent of the wastes they list (Banning, 1983,1984).  At
present, the most common wastes listed are solvents and metal wastes. Other wastes listed include acids, alkalis,
other inorganic chemicals, organics and solvents, and metals and metal sludges.

 Waste  Minimization  in  Metal  Parts  Cleaning  Operation
                                recycling arrangements include toll recyclers, and waste exchange/brokerage.
                                Toll recyclers
                                Toll recyclers offer services to generators by supplying solvent wash equip-
                                ment and solvent and waste recycling services. The solvent wash equipment
                                is maintained by these companies and the solvent is replaced periodically. The
                                used solvent is recycled at an off-site facility.  Costs for these services range
                                from 50-90% of new solvent cost.

                                Waste exchange and brokerage
                                This is not a technology but an information service. A waste exchange can
                                match a generator of waste with a facility  that can use the waste as a raw
                                material. Commercial waste brokerage services are also available. A waste
                                generator is matched with a potential waste  user who can utilize the waste as
                                a feedstock. Matching generators and users is based on the knowledge of raw
                                material inputs and wastes and product outputs of individual industries and
                          Table 7.  Facility Characteristics to Be
                     Considered in Choosing an Off-Site Recycler
   Permits held by the facility.
   Types of solvent wastes managed.
   Ability to meet solvent purity specifications if solvent is to be returned to the generator.
   Availability of registered trucks to transport the solvent wastes.
   Distance to the recycling facility and associated transportation costs.
   Available laboratory facilities and analytical procedures.
   Record keeping practices.
   Availability of custom recycling services (e.g., vendor-owned recycling units that can be operated on the
   generators property).
   Expertise on in-plant waste management strategies and process controls.
   Insurance for recycling/treatment/disposal operations.
   Disposal procedures for still bottoms and solvents that cannot be recycled.
   State regulatory agency's compliance records on the facility.
   Current customers' comments on the facility.
   Facility's financial stability.

   Source: Radimsky, 1984.

   Waste   Minimization  in Metal  Parts  C I
                                                                             n g  Operations

Aqueous cleaning comprises a wide range of water-based cleaning methods
that use water, detergents, acids, and alkaline compounds to displace soil
rather than dissolving it in organic solvent. Aqueous cleaning has been found
to be a viable substitute for many parts cleaning operations currently using
solvents. Its principal disadvantage is that the parts are wet after cleaning and
ferrous parts easily rust in this environment. (However, the use of warm (140-
150°F) air for drying is less costly than the cost associated with solvent usage
and disposal and there are additives available to prevent short term rusting).
Also, aqueous cleaning may not be suitable for electronic components since it
may leave conductive residue.

Waste minimization techniques for reducing wastes from aqueous cleaning
include  substitution  alternatives, use of less hazardous compounds,  and
maintaining solution quality.
3.5  Substitution Alternatives for Aqueous Cleaners
                                  Abrasives, water, or steam are less hazardous than acid or alkaline cleaners,
                                  and may be equally or more effective.  An example in which an abrasive
                                  cleaning system was successfully substituted for an alkaline cleaner is pro-
                                  vided below.
3.6  Use of Less Hazardous Acid or Alkaline Compounds •
                                  The aluminum processing industry widely uses deoxidizers and desmutters
                                  based on chromic acid which is highly toxic and a possible carcinogen. By
                                  substituting a nonchromated deoxidizer, use of a hazardous product can be
                                  eliminated. The latter products are based on ferric sulfate which is easily
                                  treated for disposal (Weast 1988).
3.7 Maintain Solution Quality.
                                  As was discussed under general waste minimization options for solvent use,
                                  maintaining solution quality reduces the need for replacement and disposal.
                                  Ways to achieve this goal include precleaning inspection, avoiding unneces-
                                  sary loading, providing continuous heating, proper solution make up, remov-
                                  ing sludge promptly, and monitoring cleaning solution strength.

           Precleaning inspection  All parts entering the tanks should be free of solvents and other cleaners. For
                                  parts that are first mechanically cleaned, water-based abrasives and cutting
                                  oils should be used to reduce the cleaning load.  Precleaning of the parts in a
                                  hot water bath is often effective in reducing the load on the cleaner. This initial
                                  precleaning stage can often be made up from the last rinse stage of the cleaning
                                  operation and should employ demineralized water.
   Substituting an abrasive cleaning system for an alkaline bath
   A manufacturer of fabricated metal products cleaned nickel and titanium wire in an alkaline chemical bath prior
   to using the wire in its product. In 1986, the company began to experiment with a mechanical abrasive system.
   The system worked, but required passing the wire through the unit twice for complete cleaning.  In 1987 the
   company bought a second abrasive unit and installed it in series with the first unit.  This system allowed the
   company to completely eliminate the chemical cleaning bath (USEPA, 1988B).

 Waste  Minimization  in  Metal  Parts   Cleaning  Operations

Precleaning inspections of the parts may also help in establishing the proper
temperature and concentration at which to operate the bath. Quite often, bath
temperatures and/or concentrations are increased in an attempt to improve
efficiency. While this works in many cases, some soils can become set at higher
temperatures and concentrations.  When bath oils and solids are present on a
part, the rapid removal of the oil due to higher bath temperature creates a
difficult-to-remove solid. Proper cleaning may require a lower temperature,
longer soak time, and some form of agitation.
     Avoid unnecessary loading  When using an alkaline cleaner, alkalinity may be reduced by the acidity of the
                                soils removed, reaction of the alkali with carbon dioxide in the air used for
                                agitation, and reaction of the cleaner components with hard water salts
                                (Spring, 1963). In some applications, the detrimental effects of carbon dioxide
                                and hard water can be as significant as the effect of soil loading. Quite often,
                                10 to 25 percent of the cleaner can be consumed due to water softening.

                                In addition to consuming expensive cleaner, large amounts of solids form in
                                the bath which may then interfere with cleaning. These solids can also form
                                scale on the heating tubes and reduce heat transfer efficiency. Cleaner con-
                                sumption can be very high when heated cleaning baths are used and large
                                amounts of hard water are added as evaporation make-up. Solutions to these
                                problems include use of mechanical agitation instead of air and use of softened,
                                demineralized, or deionized water.

     Provide continuous heating  For tanks containing alkaline cleaner that are well insulated, properly covered,
                                and located where ambient temperatures are not too low, there are benefits to
                                be gained if the tank is not allowed to cool overnight. Derived benefits include
                                reduced absorption of carbon dioxide (i.e. less reduction of alkalinity) and
                                fewer rejects during production start-up due to inadequate temperature.
                                Occasional cooling of the tank should be performed to allow for the split out
                                and removal of oil. Proper heating and cooling cycles will depend on the types
                                of air encountered, the types of cleaning agents used, and the workload on the

       Proper solution make-up  Great care should be exercised when making up cleaning solutions.  If the
                                water is too hot, boil over can occur due to the heat of solution. If the water
                                temperature is too low, the liquid or solid cleaner will sink to the bottom and
                                not mix properly. With cleaners that  contain inhibitors, failure to allow for
                                complete mixing can lead to attack of metal parts or the tank itself. A helpful
                                procedure is to formulate baths at the end of a shift so that the components have
                                time to dissolve and mix before the start of production.  For systems without
                                good mixing controls, the use of liquids should be favored over solids or

Waste   Minimization  in  Metal  Parts  Cleaning  Operations
Good mixing is achieved by adding a mixing system to the tank. By installing
a three way valve on the main header of the pump exit, solution can be re-
diverted to the chemical entry area instead of through the spray nozzles. This
provides for easier dissolution of chemicals through a greater number of
turnovers (less pressure drop means higher pumping rates), and elimination
of potential plugging of the nozzles when dissolving solids.
      Remove sludge and soils
Removing sludge and soils from aqueous cleaning soak tanks will reduce
chemical use by increasing the permissible time interval between dumping
and total cleanout of the tank.

Alkaline cleaners are available which allow the separation of excess oily soil
from the cleaner.  These formulations involve the use of surfactants that are
good detergents but poor emulsifiers. Agitation of the bath during the work
shift causes a temporary emulsification which keeps the soil in suspension.
After a prolonged period of inactivity (usually overnight), the oily soils float
to the surface where they are skimmed off.  This method is quite effective with
mineral oil-type soils but is less so with fatty oils.
     Monitor cleaning solution
Analytical checks of solution strengths should be made on a routine basis. The
correction of solution strength by making small and frequent additions is
much more effective than making a few large additions. Analytical checks can
be performed by the operator utilizing simple titration techniques (does the
addition of a given amount  of reagent to a known volume of cleaner and
indicator result in a color change?). Full scale titration tests may be performed
by the lab on a less frequent basis. An accurate log of all tests and cleaner
additions should be kept at all times. Occasional testing of the reagents should
also be performed.
       Equipment maintenance  As discussed under solvent cleaning, rack systems should be maintained in
                               good condition, free from cracks, rust, and corrosion. Metal tanks should be
                               properly coated with protective finishes both inside and out.  Plastic linings
                               should be used in deionized water rinse tanks since these tanks tend to rust
                               rapidly. Use of plastic tanks can eliminate this problem. Spray nozzles should
                               be inspected regularly to avoid clogging.
Reducing chemical use and waste in a bath cleaning system
Liquid-Life makes a 100-gallon per minute separator unit that operates in conjunction with a cleaning bath
(solvent, alkaline or acid). The separator unit continuously removes sludge and particulate matter from the bath.
A pump, hydrocyclone, and sludge retention tank make up the unit. Waterloo Industries Inc., of Waterloo, Iowa,
installed the Liquid-Life unit for its alkaline cleaning system, used to clean the steel cabinets it manufactures prior
to phosphate-coating the cabinets. The Liquid-Life unit has enabled Waterloo to reduce its chemical costs by 20
percent, clean out its alkaline bath system every 13 weeks instead of every four weeks, and do less maintenance
on the cleaning operation since the pump is the only moving part in the system (Anonymous, March 1982).

 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
Another important item to maintain regularly is the float valve that supplies
make-up water to tanks of heated cleaning solution. Float valves are used to
maintain the level in the tank so that the heating coils / elements do not become
exposed. While maintaining an adequate level is extremely important, it is also
important that the valve does not leak and result in dilution of the cleaner.  In
addition to maintenance, making frequent analytical checks is a good way to
detect slow leaks.
               Reduce drag-out  If possible parts should be racked so that surfaces are nearly vertical and the
                                longer dimensions are horizontal. (For example, a rectangular part should be
                                racked so that while its planes are vertical, its long axis is horizontal.)  If the
                                lower edge is tilted, the run-off will occur at a corner rather than the entire edge.
                                As shown in Table 8, proper racking can reduce solution drag-out. Racking
                                parts so that their planes  are  vertical is preferable to racking the planes
                                horizontally (i.e., oriented like the top of a table). Drag-out can also be reduced
                                by draining parts thoroughly, installing drain boards, reducing the concentra-
                                tion of cleaner, and by increasing solution temperature.

          Increase the degree of  Rinse tanks should be agitated for maximum rinsing efficiency. Heating the
        rinsing efficiency while  water may also be effective but care should be taken that the soils present do
             reducing water use  not become set. Ways to further increase efficiency while reducing water usage

                                Use of demineralized water

                                Following a final rinse, the contaminants contained in the rinse will remain on
                                the workpiece. As the parts dry, spotting or rusting may occur.  For items on
                                which minor residues cannot be tolerated, the use of demineralized water is
                                standard.  Using demineralized water will also reduce the amount of sludge
                                generated during wastewater treatment and may allow the direct reuse of rinse
                                water as make-up to the cleaning bath.
 Reducing drag-out
 Parts that have recesses or cavities may carry significant amounts of cleaning solution with them when they are
 removed from a bath. Improved rack design, including proper tilting of long horizontal bars, reduced the
 amount of drag-out from a cleaning bath associated with an electroplating operation, according to a report by
 Pioneer Metal Finishing Inc., of Franklinville, New Jersey. Other drag-out reducing measures include tilting a
 part during withdrawal, or drilling small holes in the part to provide for drainage during removal.

 Using deionized water rinse
 It has been reported (Spring 1963; Brown, Spring, and Hennessy 1955) that many in the steel fabricating industry
 were troubled with the pinpoint rusting of steel "blackplate." Experiments showed that a residual amount of
 alkaline cleaner residue plus hard water produced this type of rusting during storage at slightly  humid
 conditions. Lab tests showed that this type of rusting only occurred when hard water and alkaline salts were
 present. Rinsing in hard water only resulted in heavy streak rust while use of deionized water produced trace
 or no rust.  A final rinse in distilled water was utilized to prevent rusting.

Waste   Minimization  in  Metal Parts  Cleaning Operations
              Table 8.  Drag-Out for Various Rack Configurations

  Vertical parts, well drained

  Vertical parts, poorly drained

  Vertical parts, very poorly drained

  Horizontal parts, well drained

  Horizontal parts, very poorly drained

  Cup-shaped parts, very poorly drained

  Source:  Durney, 1984.
Drag-out, gal/100 ft2






8.0 to > 24.0
                  Table 9.  Flow Rates for Five Rinsing Systems

 Single rinse

 Two rinses in series, equal flow of fresh rinse
 water to each tank

 Three rinses in series, equal flow of fresh rinse water
 to each tank

 Two counterflow rinses, fresh water feed to second tank only

 Three counterflow rinses, fresh water feed to third tank only

 Source: Durney, 1984.
   Flow (gpm)






 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
Counterflow rinsing

Counterflow rinse systems should always be used to reduce overall water
consumption and subsequent treatment requirements.  A comparison of 5
rinse systems is illustrated in Table 9.

Spray rinsing

Rinsing efficiency can be increased by installing spray systems. Spraying parts
with fresh water as they are raised above the rinse equals the equivalent of
1/2 of a counterflow bath.

Installation of fog nozzles

Fog nozzles use much less water than conventional spray systems. Fog nozzles
also benefit aqueous cleaned parts by covering the parts, thus preventing
solution from drying on parts. Solution drag-out is reduced.
    Employ closed loop systems  For pickling applications, consider a closed loop acid pickle system as shown
                                in Figure 8. This system consists of four essential items (Krofchak and Stone

                                       A synthetic fiber fume filter to recover acid vapors

                                       Unlike wet scrubbers/ these filters do not produce large volumes of
                                       waste water and the recovered acid  can be returned directly to the

                                    •   Use of indirect heating (instead of live steam inj ection) and agitation
                                       to  maintain cleaning efficiency and  acid concentration.

                                    •   Employment of a multistage counter-current rinsing sequence

                                       Rinse water from the first stage can be used as make-up to the acid
                                       tank.  This avoids the need for treating a stream that contains 70 to 80
                                       percent of the dragged-out acid. Rinse water from subsequent stages
                                       can be used as make-up for preceding stages.

                                    •   Use of a cooling or evaporative crystallizer to recover ferrous sulfate
                                       from spent sulfuric acid baths
            Proper parts drying
        For facilities employing hydrochloric acid, proven commercial proc-
        esses can be employed to recover iron and hydrochloric acid.

 After a water rinse, it is quite common to dry the parts using compressed air.
 Unless great care is taken to ensure the removal of oil, water, and dirt from the
 air stream, resoiling of the parts will almost certainly occur. Automated drying
 ovens might be a more viable alternative.

Waste   Minimization  in  Metal  Parts  Cleaning  Operations
                    Figure 8.  Acid Pickle Closed-Loop System
Water & Acid Mist
                   '   -~-•.:..•  ~
               »^^:^»;^^4^-^fc.ji;^ -'* ir/s
               lipiclcie'Bath '"
                       Rinse 1
                         ^Iron Sulfate
                          Iron Hydroxide
Rinse 2
                                                                                    _ Fresh

 Waste   Minimization  in  Metal  Parts   Cleaning  Operations

Abrasives can be used in tumbling barrels or applied to a buffing wheel or
machine. Other mechanical abrasive cleaning methods include air-assisted or
water-assisted blasting, brushing, vibratory processes, centrifugal barrel fin-
ishing (CBF), centrifugal disc finishing, spindle finishing, and use of natural
mass finishing abrasives.

Waste from buffing operations consists of worn out cloth wheels saturated
with abrasives, metal particles, binder, and various oxides. Waste from liquid-
based mass finishing operations consists of abrasives,  metal particles, and
water and oxides dispersed in a slurry.  Alkaline  and acid  cleaners are
sometimes added to abrasive slurries in order  to improve cleaning action.
These slurries are discharged  when the abrasive has undergone a given
amount of attrition.

Options for reducing wastes associated with abrasive cleaning include:
Use of greaseless
or water-based binders
for buffing or polishing
When oil-based binders are used, the frictional heat generated during buffing
can cause the binders to burn. This in turn leads to the requirement for
additional cleaning with alkaline soaks.  When properly used, greaseless
compounds produce parts that leave the wheel clean and dry. Greaseless
compositions also tend to adhere to the surface of the wheel so that wheel life
is extended.
Use of liquid spray compositions Liquid spray abrasive systems are usually water-based abrasives that are
                                applied directly to the buffing wheel. Wheel wear due to compound defi-
                                ciency, compound waste due to over-application, and post-cleaning require-
                                ments are all significantly reduced or eliminated when a spray gun with liquid
                                abrasive spray is used.
Control water level in mass
finishing equipment
Mass finishing operations are carried out in aqueous solutions using abrasives
or non-abrasive compounds.  Water level control is extremely important in
order to achieve maximum efficiency in mass cleaning operations.  If not
enough water is used, parts leaving the equipment will be dirty. Too little
water will increase the attrition rate of the abrasive and increase replacement

 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
                               After promising waste minimization measures for a parts cleaning operation
                               have been identified, they should be evaluated for technical and economic
                               feasibility and, if found satisfactory, they should be implemented. For those
                               methods that are found to be economically infeasible, additional analysis
                               including consideration of "hidden " cost, liability, public image and other
                               components (USEPA, 1988C) should be performed before dropping an option.

                               Adopting specific waste minimization measures may not be easy or straight-
                               forward. A number of factors (Table 10) may affect the readiness  of an
                               organization to implement measures that require changes in procedures,
                               equipment, or employee responsibilities. Developing a strategy to overcome
                               these barriers should be an integral part of waste minimization planning. This
                               strategy should include establishment of a working group of personnel repre-
                               senting the affected departments:  Health and Safety, Production, Mainte-
                               nance, Process Control,  Purchasing, and Facilities, for example. (USEPA,

                               As increased regulation raises the cost of waste treatment and disposal, efforts
                               to decrease waste volumes and toxicity become more economically justifiable.
                               Implementing waste minimization techniques to reduce cleaning waste can
                               produce treatment and disposal cost savings which more than offset the expen-
                               diture. In additionfmaterial costs, regulatory compliance, and other costs can
                               be cut since the life of the cleaning solutions will be lengthened.

                               Most of the measures discussed in this pamphlet would involve minimal
                               capital outlays. For example, proper equipment operation requires only that
                               management thoroughly train the employees using the equipment and that the
                               equipment be correctly maintained. These low-cost measures generally have
                               a fast  payback and are among the first a firm should implement.  Making
                               employees aware of the cost of waste generation due to cleaning operations
                               and involving them  in identifying solutions may encourage the design of
                               more efficient production processes.

                               With the adoption of efficient production processes and the waste-minimizing
                               measures presented here, companies with parts cleaning operations should be
                               able to reduce their  waste  disposal  costs and liabilities, and reduce  their
                               contribution to the environmental problems associated with waste disposal.

 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
                  Table 10.  Some Barriers to Waste Minimization
          A new operating procedure will reduce waste but may also be a bottleneck that decreases the
          overall production rate.

          Production will be stopped while the new process equipment is installed.

          A new piece of equipment has not been demonstrated in a similar service. It may not work here.

          Adequate space is not available for the installation of new equipment.

          Adequate utilities are not available for the new equipment.

          Engineering or construction manpower will not be available in time to meet the project schedule.

          Extensive maintenance may be required.

   Quality Control
          More intensive QC may be needed.

          More rework may be required.

   Client Relations/Marketing
          Changes in product characteristics may affect customer acceptance.

          A program to reduce inventory (to avoid material deterioration and reprocessing) may lead to
          stockouts during high product demand.

          Inadequate cost evaluations or coordination with financial department.

          Existing stocks (or binding contracts) will delay the replacement of a hazardous material with a
          nonhazardous substitute.

          Accepting another plant's waste  as a feedstock may require a lengthy resolution of regulatory

   Waste Treatment
          Use of a new nonhazardous raw material will adversely impact the existing wastewater treat-
          ment facility.
   Source: USEPA, 1988B.

 Waste   Minimization  i n M e t a I  Parts  Cleaning  Operations
                             Aerolyte Systems Company. "Dry paint stripping."  Aerolyte Division of
                                 Clemco Industries.  Burlingame, Calif., 1985.

                             American Society for Metals Committee on Selection of Cleaning Processes.
                                 "Selection of cleaning processes." Metals Handbook.  The American
                                 Society for Metals, Cleveland, Ohio, 1948.

                             American Society for Testing and Materials. Handbook of Vapor Degreasing.
                                 Special Technical Publication 310A. Philadelphia, April 1976.

                             Anonymous. "Solvent vapor recovery and VOC emission control." Pollution
                                 Engineering, June 1986.

                             Anonymous.  "Activated carbon fiber aids in solvent recovery." Chemical
                                 Engineering. Aug. 24,1984, pp. 63-64.

                             Anonymous. "Vacuum rotary dryer recovers solvent." Chemical Processing,
                                 Nov. 1982, p. 36.

                             Anonymous.  "Cryogenic paint stripping."  Products Finishing. December
                                 1982, pp. 54-57.

                             Anonymous. "Cyclonic separator saves pretreatment chemicals." Products
                                 Finishing, March 1982, pp. 88-90.

                             Anonymous.  "Solid bed absorption system regenerated with vacuum."
                                 Chemical Processing, November 1982, p. 128.

                             Anonymous. "Solvent recycling system saves costs and cleans air." Chemical
                                 Engineering, March 10,1980, pp. 91-92.

                             Applegate, L.E.  "Membrane separation processes." Chemical Engineering,
                                 June 11,1984.

                             Banning, W.  "An Assessment of the Effectiveness of the Northeast Industrial
                                 Waste  Exchange in 1984."  Northwest Industrial Waste Exchange,
                                 Syracuse, N.Y., November 1984.

                             Banning, W., and S. Hoefer. "An Assessment of the Effectiveness of the
                                 Northeast Industrial Waste Exchange in 1983."   Northeast Industrial
                                 Waste Exchange, Syracuse, N.Y., November, 1983.

                             Baumer, R.A.  "Making environmental  audits."   Chemical  Engineering,
                                 November 1,1982, p. 101.

 IV a S t e   Minimization  in  Metal  Parts  Cleaning  Operations
                                Briggs, J.L., and H.A. Goad.  "A comparative study of aqueous and solvent
                                   methods for cleaning metals." Report by Rockwell International Corp., El
                                   Segundo, Calif, to U.S. Energy Research and Development Administra-
                                   tion, Albuquerque Operations Office, Albuquerque, N.M.  NTIS No. PC
                                   A02/MF A01,19 April 1976,16 pp.

                                Brown, Spring and Hennessy. Iron Age, December 1,1955.

                                California Department of Health Services.  "Solvent waste reduction alterna-
                                   tives symposia."  Conference  Proceedings.   Prepared  for California
                                   Department of Health Services by ICF Consulting Associates, Inc., 1986.

                                California Department of Health Services.  "Guide to solvent waste reduction
                                   alternatives." Prepared for California DHS by ICF Consulting Associates,
                                   Inc., October 10,1986, Final Report.

                                California  Department of Health Services.  "California Waste Exchange."
                                   Newsletter, Vol. 1, No. 1,1986.

                                Christensen, C. "Waste Minimization - Degreasing Solvents." Symposium
                                   Proceedings, Process Technology '88 The Key to Hazardous  Waste
                                   Minimization.  August 15-18,1988. Sacramento, Calif. Sponsored by Air
                                   Force Logistics Command.

                                Conservation Foundation. America's Waste: Managing for Risk Reduction.
                                   The Conservation Foundation, Washington, D.C., 1987.

                                DeSoi, H.J. "Cyanide destruction and waste reduction in the electroplating
                                   industry."  Proceedings, New Jersey Source Reduction of Hazardous
                                   Waste  Seminar, New Jersey Dept. of Environmental Protection, Division
                                   of Waste Management, 1984.

                                Dow Chemical USA. "Economical and efficient vapor degreasing with chlo-
                                   rinated solvents from Dow." FORM No. 100-6096-485.  Dow Chemical
                                   Corporation, Midland, Mich., 1985. 49 pp.

                                DuPont de Nemours & Co., Inc. Freon Cleaning Agents, FS-30 A-E (five part
                                   series,  product literature). Wilmington, Del. 1987.

                                Durney, L.J.  "How to improve your paint stripping." Products Finishing,
                                   December, 1982, pp. 52-53.

                                Durney, L.J., ed. Electroplating Engineering Handbook. 4th Edition.  Van
                                   Nostrand Reinhold, New York, 1984.

                                Erickson, P.R. and W.M. Thropp. "Improved washing of machined parts."
                                   Production Engineering, March 1977.

Waste   Minimization  in Metal  Parts  Cleaning  Operations
                               Evanoff, S.P. Personal communication with Jacobs Engineering Group, No-
                                  vember 1988.

                               Evanoff, S.P., et al. Alternatives to Chlorinated Solvent Degreasing - Testing,
                                  Evaluation and Process Design. Proceedings of 3rd Annual Hazardous
                                  Materials Management Conference West, Long Beach, Calif. December

                               Forth, K. (assoc. ed.) "Stripped clean and dry." Aviation Equipment Main-
                                  tenance, October 1985.

                               Handbook of Industrial Blasting.  "Section 1 - Automotive parts cleaning."
                                  Inland Manufacturing Company, Omaha, Nebraska, 1972.

                               Hayes, M.F. "Chlorinated CFC Solvent Replacement in the Electronics Indus-
                                  try: The Terpene Hydrocarbon Alternative."  Proceedings of 3rd Annual
                                  Hazardous Materials Management Conference West, Long Beach, Califor-
                                  nia. December 1987.

                               Hayes, M.E. "Naturally Derived Biodegradable Cleaning Agents: Terpene -
                                  Based Substitutes for Halogenated Solvents."

                               Higgins, T.E.   "Industrial process modifications to  reduce generation of
                                  hazardous waste at DOD facilities: Phase I Report." Prepared for the DOD
                                  Environmental Leadership Project Office and U.S. Army Corps of Engi-
                                  neers by CH2M Hill, Washington, D.C., February 1985.

                               Hodel, A.E., and KM. Bonady. "Guide to filtration." Chemical Processing,
                                  Jan. 1986, pp. 52-74.

                               Hughes, T.H., K.E. Brooks, B.W. Norris, B.M. Wilson, and B.N. Roche. A
                                  Descriptive Survey of Related Organic Solvents. University of Alabama,
                                  Tuscaloosa, Ala., August 1985.

                               Huisingh, D., L. Martin, H. Hilger, and N. Seldman. Profits from Pollution
                                  Prevention. Institute for Local Self-Reliance, Washington, D.C., 1986.

                               Industrial Material Exchange. "Assessment Report." Illinois Environmental
                                  Protection Agency, Springfield, 111., 1985.

                               Isooka, Y.,  Y. Imamura,  and Y. Sakamoto.  "Recovery and reuse of organic
                                  solvent solutions." Metal Finishing, June 1984, pp. 113-118.

                              Joshi, S.B.  "Use of Solvent Test Kits to Monitor Solvent Condition and
                                  Maximize Solvent Utilization."  Symposium Proceedings, Process Tech-
                                  nology '88:  The Key to Hazardous Waste Minimization August 15-18,
                                  1988. Sacramento, CA. Sponsored by Air Force Logistics Command.

Waste   Minimization   in  Metal  Parts  Cleaning  Operations
                                Katzel, J. "Putting personal computers to work in the plant." Plant Engineer-
                                   ing, April 24,1986, p. 40.

                                Kenson, R.E.  "Recovery and reuse of solvents from VOC air emissions."
                                   Environmental Progress, August 1985, pp. 161-165.

                                Kohl, J., J. Pearson, M. Rose and P. Wright. Managing and Recycling Solvents
                                   in the Furniture Industry. Industrial Extension Service, School of Engi-
                                   neering, 116 pp. North Carolina State University, Raleigh, N.C., May 1986.

                                Kohl, J., P. Moses, and B. Triplett. Managing and Recycling Solvents: North
                                   Carolina Practices, Facilities, and Regulations.  North Carolina State
                                   University, Raleigh, N.C., 1984.

                                Krofchak, D., and J. Neil Stone. Science and Engineering for Pollution - Free
                                   Systems.  Ann Arbor Science Publishers, Ann Arbor, Mich., 1975.

                                Huisingh, D., H. Hilger, S. Thesen, and L. Martin. Proven Profit From Pollution
                                   Prevention. Institute for Local Self-Reliance, Washington D. C. 1985.

                                Leitert, F.C., and A.E. Model.  "Vacuum, agitated, thin-film evaporator strips
                                   high-boiling solvents from heat-sensitive products." Chemical Process-
                                   ing, mid-Nov., 1985, pp. 122-123.

                                Lucas, D.F. "A New Solvent for Industrial Cleaning." Proceedings, 4th Annual
                                   Hazardous Materials Management Conference West, Long Beach, Califor-
                                   nia. November 1988.

                                Lyman,T.(ed.) "Blast cleaning of metals." Metals Handbook. The American
                                   Society for Metals, Cleveland, 1948.

                                Master Chemical Corporation.  Company brochure.  Metalworking Fluids
                                   Division, Perryburg, Ohio, 1985.

                                Mehra, D.K.  "Selecting evaporators." Chemical Engineering, February 3,
                                   1986, pp. 56-72.

                                North Carolina Pollution Prevention Pays Program.  "Environmental audit-
                                   ing." State of North Carolina, 1985.

                                Pace Company Consultants  and Engineers, Inc.  Solvent Recovery in the
                                   United States, 1980-1990, Houston, Texas, 1983.

                                Pauli & Griffin Company.  "The PRAM series plastic reclaimable abrasive
                                   machines." (product literature). Aeronautical Products Division, Vacav-
                                   ille, Calif., 1984.

Waste   Minimization  in  Metal  Parts  Cleaning  Operations
                               Piedmont Waste Exchange. Annual Report. Charlotte, North Carolina.

                               Rimberg, D. "Minimizing maintenance makes money." Pollution Engineer-
                                   ing. Vol. 12, No. 3,1980, p. 46.

                               Roberts, R.A.  "Plastic material blasting - PMB; interim report on stripping
                                   paint from the second F-4E prototype at Hill AFB, Utah." Unpublished
                                   report.  Hill Air Force Base, Ogden, Utah, 20 May 1985.

                               Roembke, R.,  J.  Mode, and A.E. Hodel.  "Thin-film evaporator recovers
                                   solvents continuously." Chemical Processing, Nov. 1985, pp. 28-29.

                               Sarokin, D.J., W.R. Muir, C.G. Miller, and S.R. Sperber.  Cutting Chemical
                                   Wastes. INFORM, Inc., New York, 1985.

                               Schwartz, S.I., D.R. Donegan, N.S. Ostrom, T. Emmert, and D. Sivas. "Manag-
                                   ing the Electronics Industry's Hazardous Wastes: Technology and Eco-
                                   nomics of Alternatives to  Land  Disposal."   Report to the California
                                   Legislature, Calif. Dept. of Health Services, and Golden Empire Planning
                                   Center. July  1985.

                               Schwartz, S.I. "Recycling of Hazardous Waste Solvents: Economic and Policy
                                   Aspects."  Solvent Waste Reduction Alternatives Symposia Conference
                                   Proceedings. Los Angeles, CA. Sponsored by California Department of
                                   Health Services.

                               SFE Technologies, private communication with Jacobs Engineering, February

                               Shields, E.J.  "Prevention and control of chemical spill incidents." Pollution
                                   Engineering. Vol. 12, No. 4,1980, p. 52.

                               Singh, J.B., and R.M. Allen. "Establishing a preventive maintenance program."
                                   Plant Engineering, February 27,1986, p. 46.

                               Smith, C.  "Troubleshooting vapor degreasers." Products Finishing, Novem-
                                  ber 1981.

                               Spencer, L.F. "The cleaning of metals: Part 3 - Emulsion and diphase cleaning."
                                  Metal Finishing, June 1963.

                               Spencer, L.F.  "The cleaning of metals:  Part 1 - Alkaline cleaning.  Metal
                                  Finishing, April 1962, pp. 59-60.

                               Spring, S. "Cleaning and detergency." Metal Finishing, November 1974.

 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
                               Spring, S.  Metal Cleaning. Reinhold Publishing Corp., New York, 1963.

                               Taylor, P. "M-Pyrol Solvent - A Practical Replacement for Hazardous Sol-

                               3M Corporation. Ideas - A Compendium of 3M Success Stories. St. Paul,

                               Traverse, L.J. "Source reduction by substitution and'reuse." Proceedings,
                                   Massachusetts Hazardous Waste Source Reduction Conference, Massa-
                                   chusetts Dept. of Environmental Management, Bureau of Solid Waste
                                   Disposal, Mass., 1984.

                               U.S. Congress, Office of Technology Assessment. From Pollution to Preven-
                                   tion. OTA-ITE-317. Washington, D.C., September 1986.

                               USEPA.  Solvent Waste Reduction Alternatives Seminar,  Speakers Papers.
                                   CERI-88-06.  U.S. Environmental Protection Agency, Center for Environ-
                                   mental Research Information. Office of Solid Waste and Emergency
                                   Response, 1988.  (1988A).

                               USEPA.  Waste  Minimization Opportunity Assessments Manual. EPA/
                                   625/7-88-003. U.S. Environmental Protection Agency, Hazardous Waste
                                   Engineering  Research Laboratory, Cincinnati, April 1988.  (1988B).

                               USEPA. "Waste Minimization Benefits Manual, Phase I". U.S. Environmental
                                   Protection Agency Office of Solid Waste, Office of Policy, Planning and
                                   Evaluation.  December 1988 (1988C).

                               USEPA. Analysis of Treatment and Recycling Technologies for Solvents and
                                   Determination of Best Available  Demonstrated Technologies  (BOAT),

                               USEPA. Report  to Congress, Waste Minimization, Volumes 1-5. EPA/530-
                                   SW-86-041. U.S. Environmental Protection Agency, Office of Solid Waste.
                                   U.S. Government Printing Office, Washington, D.C., 1986.

                               USEPA. 1983. "Preliminary analysis of possible substitutes for 1,1,1-trichlo-
                                   roethane, tetrachloroethene, dichloromethane, tetrachloromethane,
                                   trichloroethene, and trichlorotrifluoroethane." Final report by GCA Cor-
                                   poration, Chapel Hill, NC  to U.S. Environmental Protection  Agency,
                                   Chemical Unit, Office of Policy and Resource Management, Washington,
                                   D.C. GCA-TR-CH-83-06.  May 1983.
                               USEPA.  "Organic solvent cleaners - background information for proposed

Waste   Minimization  in  Metal  Parts  Cleaning  Operations

                                   standards." EPA-450-2-78-045a. U.S. Environmental Protection Agency,
                                   Office of Air Quality Planning and Standards, Research Triangle Park,
                                   N.C., 1979.

                               USEPA.  "Cleaning alternative to organic solvent degreasing."  Technical
                                   report prepared for the U.S. Environmental Protection Agency, Effluents
                                   Guideline Division, by S.V. Bauks and K.J. Dresser.  Washington, D.C.,
                                   December 1979.

                               USEPA. "Control of volatile organic emissions from solvent metal cleaning."
                                   EPA- 450/2-77-022. U.S. Environmental Protection Agency, Office of Air
                                   /Quality Planning and Standards, Research Triangle Park, N.C., Novem-
                                   ber 1977.

                               Vatavuk, W., and R. Neveril.  "Estimating costs for air pollution systems."
                                   Chemical Engineering.  October 30,1980.

                               Wagner, L.K., Organic Surface Contamination - Its Identification, Characteri-
                                  zation, Removal, Effects on Insulation Resistance and Conformal Coatings
                                  Adhesion. Institute for Interconnecting and Packaging Electronic Circuits,
                                  Evanston, IL, September 1981.

                               Waste reduction: The untold story. Conference  proceedings; June 19-21,
                                  1985. Sponsored by League of Women Voters, Massachusetts; Environ-
                                  mental Management Center, Tufts University; and U.S. Environmental
                                  Protection Agency.

                               Weast, M.C. personal communication with Jacobs  Engineering Group, No-
                                  vember 1988.

                               West, J.  "Disc-bowl centrifuges."  Chemical Engineering. January 7, 1985,
                                  pp. 69-73.

 Waste  Minimization  in  Metal  Parts  Cleaning Operation

Associations That Can Provide Information and Direction
Relating to Waste Minimization in Parts Cleaning

                              Abrasive Engineering Society (AES)
                              1700 Painters Run Rd.
                              Pittsburg,PA 15243
                              (412) 221-0900

                              Aerospace Industries Association
                              of America (AIA)
                              1725 DeSales St., NW
                              Washington, DC 20036
                              (202) 347-2315

                              Air Pollution Control Association
                              P.O. Box 2861
                              Pittsburgh, PA  15230
                              (412) 621-1090

                              American Chemical Society
                              1155 16th St., NW
                              Washington, DC 20036
                              (202) 872-4600

                              American Electronics Association
                              2600 El Camino Real
                              Palo Alto, CA 94306
                              (415) 327-9300

                              American Electroplaters Society
                              1201 Louisiana Ave.
                              Winter Park, FL 32789
                              (305) 647-1197

                              American Society for Metals (ASM)
                              Metal Parks, OH 44073
                              (216) 338-5151

                              American Society for Testing
                              and Materials (ASTM)
                              1916 Race St.
                              Philadelphia, PA 19103
                              (215) 299-5400
Association for Finishing Processes
P.O. Box 930
One SME Dr.
Dearborn, MI  48128
(313) 271-1500

Chemical Coaters Association
Box 241
Wheaton,IL 60187
(312) 668-0949

Chemical Manufacturers
Association (CMA)
1825 Connecticut Ave., NW
Washington, DC 20009
(202) 328-4200

Chemical Specialties
Manufacturers Association
1001 Connecticut Ave., NW
Washington, DC 20036
(202) 872-8110

Electrochemical Society (ECS)
P.O. Box 2071
Princeton, NJ  08540
(609) 924-1902

Electronic Industries Association
2001 Eye St., NW
Washington, DC 20006
(202) 457-4900

Fabricating Manufacturers
Association (FMA)
7811 N. Alpine
Rockford,IL  61111
(818) 654-1902

Waste   Minimization  in  Metal  Parts  Cleaning  Operations
                               Federation of Societies for
                               Coatings Technology (FSCT)
                               1315 Walnut
                               Philadelphia, PA  19107
                               (215) 545-1506

                               Halogenated Cleaning Solvents
                               Association (HCSA)
                               Affiliate of Synthetic Organic
                               Chemical Manufacturers
                                 Association Inc.
                               1075 Central Park Ave.
                               Scarsdale,NY 10583

                               Institute for Interconnecting and
                                Electronic Circuits (IPC)
                               3451 Church St.
                               Evanston, IL  60203
                               (312) 677-2850

                               Metal Fabricating Institute (MFI)
                               710 S. Main St.
                               Rockford, IL 61105
                               (815) 965-4031

                               Metal Finishing Suppliers
                               Association (MFSA)
                               1025 E. Maple Rd.
                               Birmingham, MI 48011
                               (313) 646-2728

                               National Association of
                               Corrosion Engineers (NACE)
                               1440 S. Creek Dr.
                               Houston, TX  77084
                               (713) 492-0535

                               National Association of
                               Manufacturers (NAM)
                               1776 F St., NW
                               Washington, DC 20006
                               (202) 331-3700

                               National Association of  Metal
                               Finishers  (NAMF)
                               HIE. WackerDr.
                               Chicago, IL 60601
National Solid Wastes
Management Association
1120 Connecticut Ave., NW
Washington, DC 20036
(202) 659-4613

Semiconductor Equipment
and Materials Institute (SEMI)
625 Ellis St., Suite 212
Mountain View, CA  94043
(415) 964-5111

Semiconductor Industry
Association (SIA)
20380 Town Center Lane, Suite 155
Cupertino, CA  95014
(408) 255-3522

Society of Automotive Engineers
400 Commonwealth Dr.
Warrendale, PA 15096
(412) 776-4841

Water Pollution Control
Federation (WPCF)
2626 Pennsylvania  Ave.
Washington, DC 20037
(202) 337-2500

 Waste   Minimization  in  Metal  Parts  Cleaning  Operations
List of Periodicals That May Contain Information
Relating to Waste Minimization in Parts Cleaning

                               American Paint and
                               Coatings Journal
                               American Paint Journal Co.,
                               2911 Washington Ave.,
                               St. Louis/MO 63103.

                               Assembly Engineering
                               Hitchcock Publishing Co.,
                               Geneva Rd.,
                               Wheaton,IL 60187

                               Cleaning - Finishing - Coating
                               American Society for Metals,
                               Metals Park, OH 44073

                               Electronic Packaging
                               and Production
                               Milton S. Kiver Publications, Inc.,
                               222 W. Adams St.,
                               Chicago, IL 60606

                               Industrial Finishing
                               Hitchcock Publishing Co.,
                               Hitchcock Building,
                               Wheaton,IL 60187

                               Iron Age
                               Chilton Co., Inc.,
                               Radnor, PA 19089

                               Journal of Coatings Technology
                               Federation of Societies for Coating
                               1315 S. Walnut St., Suite 830,
                               Philadelphia, PA 19107

List of Abstract Publications
                               American Society for Metals
                               Annual Review of Metals Literature
                               Cleaning and Finishing, Section L.

                               American Society for Testing
                               and Materials
                               Special Technical Publication 90
                               Metal Cleaning Abstracts
Metal Finishing
Metals and Plastics
Publications, Inc.,
One University Plaza,
Hackensack, NJ 07601

Metal Finishing Guidebook
and Directory
Metals and Plastics
Publications, Inc.
One University Plaza,
Hackensack, NJ 07601

Metal Finishing Journal
Fuel and Metallurgical
Journals Ltd.,
John Adam House,
John Adam St.,
London WC 2N 6JH, England

Metal Finishing Plants
and Processes
Finishing Publications Ltd.,
28 High St.,
Teddington, Middlesex, England

Metal Progress
American Society for Metals,
Metals Park, OH 44073

Plating and Surface Finishing
American Electroplaters Society,
1201 Louisiana Ave.,
Winter Park, FL 32789
Metal Finishing Abstracts
Finishing Publications Ltd.,
28 High St.,
Teddington, Middlesex, England