>EPA
United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/625/R-92/011
October 1992
Technology Transfer
Guides to Pollution
Prevention
The Metal Finishing
Industry
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EPA/625/R-92/011
October 1992
GUIDES TO POLLUTION PREVENTION
The Metal Finishing Industry
RISK REDUCTION ENGINEERING LABORATORY
AND
CENTER FOR ENVIRONMENTAL RESEARCH INFORMATION
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
Printed on Recycled Paper
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NOTICE
This guide has been subjected to U.S. Environmental Protection Agency
peer and administrative review and approved for publication. Approval does
not signify that the contents necessarily reflect the views and policies of the
U.S. Environmental Protection Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
This document is intended as advisory guidance only to the metal finish-
ing industry in developing approaches for pollution prevention. Compliance
with environmental and occupational safety and health laws is the responsibil-
ity of each individual business and is not the focus of this document.
Worksheets are provided for conducting waste minimization assessments
of metal finishing facilities. Users are encouraged to duplicate portions of this
publication as needed to implement a waste minimization program.
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FOREWORD
This guide provides an overview of the major metal finishing processes
and operations that generate waste and presents options for minimizing waste
generation through source reduction and recycling. A wide variety of
processes are used in the metal finishing industry, including physical,
chemical, and electrochemical processes. Metal finishing processes generate
various waste streams, including contaminated plating baths, spent process
baths, cleaners, rinse water, miscellaneous solid waste, solvents, and air
emissions.
Reducing the generation of this waste at the source or recycling the
wastes on or off site will benefit the metal finishing industry by reducing raw
material use, reducing disposal costs, and lowering the liabilities associated
with waste disposal.
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ACKNOWLEDGMENTS
This guide is based in part on waste minimization assessments conducted
by PRC Environmental Management, Inc., San Francisco, California, for the
California Department of Health Services (DHS) and the U.S. Environmental
Protection Agency. Contributors to these assessments include David Leu,
Robert Ludwig, and Kim Wilhelm of the Alternative Technology Section of
DHS; the owners and staff of ;the metal finishing companies that participated
in this study; representatives of equipment manufacturers, chemical suppliers,
the Northern California Association of Metal Finishers, and the Metal Finish-
ers Association of Southern California; and various hazardous waste recycle/
disposal facilities. Much of the information in this guide was provided origin-
ally to the California DHS by PRC Environmental Management, Inc. in Waste
Audit Study: Metal Finishing Industry (May 1988). Battelle Memorial Insti-
tute edited and expanded this version of the waste minimization assessment
guide under subcontract to EPA (USEPA Contract 68-CO-0003). Battelle per-
sonnel contributing to this guide include Bob Olfenbuttel, work assignment
manager; Tom Bigelow and Leslie Hughes, task leaders; Dale Folsom, techni-
cal engineer; and Bea Weaver, production editor.
Teresa Harten of the U.S. Environmental Protection Agency, Office of
Research and Development, Risk Reduction Engineering Laboratory, was the
project officer responsible for the preparation and review of this guide. Other
contributors and reviewers include Frank Altmayer, American Electroplaters
and Surface Finishers Society; K. N. Wood, E. I. duPont de Nemours & Com-
pany; Clarence Roy, Rainbow Research, Inc.; William Sonntag, National
Association of Metal Finishers; Tom Adkisson, PRC Environmental Manage-
ment, Inc.; Philip A. Kodak,. Lockheed Missiles and Space Company, Inc.;
and Benjamin Fries, California Department of Toxic Substances Control.
IV
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CONTENTS
Section Page
Notice ii
Foreword . . . iii
Acknowledgments iv
1. Introduction 1
Overview of Waste Minimization 1
Waste Minimization Opportunity Assessment 1
References 4
2. Metal Finishing Industry Profile 5
Industry Description 5
Process Description 5
Waste Description . 6
3. Waste Minimization Options for Metal Finishing Facilities 8
Introduction 8
Source Reduction 8
Recycling and Resource Recovery . 20
References 27
4. Guidelines for Using the Waste Minimization
Assessment Worksheets 29
APPENDIX A:
Metal Finishing Facility Assessments:
Case Studies of Plants 45
APPENDIX B:
Where to Get Help:
Further Information on Pollution Prevention 59
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SECTION 1
INTRODUCTION
The purpose of this guide is to help the metal fin-
ishing industry identify, assess, and implement waste
minimization options. It is envisioned that the guide
will be used by metal finishing companies, particularly
plant operators and environmental engineers, as well
as regulatory agency representatives, industry suppli-
ers, and consultants. To provide the industry with the
information and guidance necessary to implement an
effective waste minimization program, this manual
contains
• A profile of the metal finishing industry and the
processes used in it (Section 2)
• Well-established and practical waste minimiza-
tion options for the industry (Section 3)
. • Waste minimization assessment guidelines and
worksheets (Section 4)
• Appendices containing case studies of waste
generation/waste minimization practices in the
industry and sources of information and help.
The worksheets and the list of waste minimization
options were developed from assessments of San
Francisco Bay Area firms in California commissioned
by the California Department of Health Services (DHS
1988). Operations, manufacturing processes, and
waste generation and management practices were sur-
veyed, and existing and potential waste minimization
options were characterized.
Overview of Waste Minimization
Waste minimization is a policy specifically man-
dated by the U.S. Congress in the 1984 Hazardous
and Solid Waste Amendments to the Resource Con-
servation and Recovery Act (RCRA). As the federal
agency responsible for writing regulations under
RCRA, the U.S. Environmental Protection Agency
(EPA) has an interest in ensuring that new methods
and approaches are developed for minimizing hazard-
ous waste, and that such information is made available
to the industries concerned. This guide is one of the
approaches EPA is using to provide industry-specific
information about waste minimization. The options
and procedures outlined can also be used in efforts to
minimize other wastes generated in a business.
In the working definition used by EPA, waste min-
imization consists of source reduction and recycling.
Of the two approaches, .source reduction is usually
considered to be the preferable method from an envi-
ronmental perspective. A few states consider waste
treatment to be a third approach to waste minimiza-
tion, but EPA does not, and therefore waste treatment
is not addressed in this guide.
Waste Minimization
Opportunity Assessment
A Waste Minimization Opportunity Assessment
(WMOA), sometimes called a waste minimization
audit, is a systematic procedure for identifying ways
to reduce or eliminate waste. Briefly, the assessment
consists of a careful review of a plant's operations and
waste streams and the selection of specific areas to
assess. After a particular waste stream or area is
established as the WMOA focus, a number of options
with the potential to minimize waste are developed
and screened. The technical and economic feasibility
of the selected options are then evaluated. Finally, the
most promising options are selected for
implementation.
In 1992, EPA published the Facility Pollution
Prevention Guide (USEPA 1992) as a successor to the
Waste Minimization. Opportunity Assessment Manual.
While the Waste Minimization Opportunity Assessment
Manual concentrated primarily on the waste types
covered in the Resource Conservation and Recovery
Act (RCRA), the Facility Pollution Prevention Guide
deals with /'multimedia" pollution prevention. It is
intended to help small- to medium-sized production
facilities develop broad-based, multimedia pollution
prevention programs. Methods of evaluating, adjust-
ing, and maintaining the program are described. Later
chapters deal with cost analysis for pollution preven-
tion projects and with the roles of product design and
energy conservation in pollution prevention. Appendi-
ces consist of materials that will support the pollution
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prevention effort: assessment worksheets, sources of
additional information, examples of evaluative meth-
ods, and a glossary.
Detailed information on conducting a WMOA is
provided in a waste minimization manual developed
by EPA. Entitled the Waste Minimization Opportunity
Assessment Manual (USEPA 1988), the document
provides instructions for conducting waste minimiza-
tion assessments and developing options for reducing
hazardous wastes. It describes the management strate-
gies needed to incorporate waste minimization into
company policies and structure and methods for estab-
lishing an ongoing company-wide waste minimization
program, conducting assessments, and implementing
options.
The four phases of a WMOA are planning and
organization, assessment, feasibility analysis, and
implementation. The steps involved in conducting a
waste minimization assessment are outlined in Fig-
ure 1 and presented in more detail in this section of
the guide. The subsequent sections of this guide pro-
vide waste minimization approaches beneficial to the
metal finishing industry and information for- then-
evaluation and implementation.
PLANNING AND ORGANIZATION PHASE
Essential elements of planning and organization for
a waste minimization program are getting management
commitment for the program, setting waste minimiza-
tion goals, and organizing an assessment program task
force.
ASSESSMENT PHASE
The assessment phase involves a number of steps:
• Collect process and facility data
• Prioritize and select assessment targets
• Select assessment team
• Review data and inspect site
• Generate options
• Screen and select options for feasibility study.
Collect Process and Facility Data
The waste streams at a facility should be identified
and characterized. Information about waste streams
may be available on hazardous waste manifests,
National Pollutant Discharge Elimination System
(NPDES) reports, toxic release inventory reports, rou-
tine sampling programs, and other sources.
Developing a basic understanding of the processes
that generate waste at a facility is essential to the
WMOA process. Flow diagrams should be prepared
to identify the quantity, types, and rates of waste gen-
erating processes. Also, preparing material balances
for the different processes can be useful in tracking
various process components and identifying losses or
emissions that may have been unaccounted for
previously.
Prioritize and Select Assessment Targets
Ideally, all waste streams in a facility should be
evaluated for potential waste minimization opportuni-
ties. With limited resources, however, a plant man-
ager may need to concentrate waste minimization
efforts in a specific area. Such considerations as
quantity of waste, hazardous properties of the waste,
regulations, safety of employees, economics, and other
characteristics need to be evaluated in selecting target
streams or operations.
Select Assessment Team
The team should include people with direct respon-
sibility for and knowledge of the particular waste
stream or area of the facility being assessed. Equip-
ment operators and people involved in routine waste
management should not be ignored.
Review Data and Inspect Site
The assessment team evaluates process data in
advance of the inspection. The inspection should fol-
low the target process from the point where raw mate-
rials enter to the point where products and wastes
leave. The team should identify the suspected sources
of waste. This may include the production process;
maintenance operations; and storage areas for raw
materials, finished products, and work in progress.
The inspection may result in the formation of prelimi-
nary conclusions about waste minimization
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The Recognized Need to Minimize Waste
i
PLANNING AND ORGANIZATION
1 Get management commitment
Set overall assessment program goals
1 Organize assessment program task force
Assessment Organization &
Commitment to Proceed
ASSESSMENT
Collect process and facility data
Prioritize and select assessment targets
Select people for assessment teams
Review data and inspect site
Generate options
Screen and select options for further study
Select New Assessment
Targets and Reevaluate
Previous Options
Assessment Report of
Selected Options
FEASIBILITY ANALYSIS
1 Technical evaluation
1 Economic evaluation
1 Select options for implementation
Final Report, Including
Recommended Options
t
IMPLEMENTATION
Justify projects and obtain funding
1 Installation (equipment)
' Implementation (procedure)
• Evaluate performance
f
Repeat the
Process
Successfully Implemented
Waste Minimization Projects
Figure 1. The Waste Minimization Assessment Procedure
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opportunities. Full confirmation of these conclusions
may require additional data collection, analysis, and/or
site visits. !
Generate Options
The objective of this step is to generate a compre-
hensive set of waste minimization options for further
consideration. Since technical and economic concerns
will be considered in the later feasibility step, no
options are ruled out at this time. Information from
the site inspection, as well as trade associations, gov-
ernment agencies, technical and trade reports, equip-
ment vendors, consultants, and plant engineers and
operators may serve as sources of ideas for waste
minimization options.
Both source reduction and recycling options should
be considered. Source reduction may be accom-
plished through good operating practices, technology
changes, input material changes, and product changes.
Recycling includes use and reuse of water, solvents,
and other recyclable materials, where appropriate,
Screen and Select Options for Further Study
This screening process is intended to select the
most promising options for a full technical and eco-
nomic feasibility study. Through either an informal
review or a quantitative decision-making process,
options that appear marginal, impractical, or inferior
are eliminated from consideration.
FEASIBILITY ANALYSIS PHASE
An option must be shown to be technically and
economically feasible in order to merit serious consid-
eration for adoption at a facility. A technical evalua-
tion determines whether a proposed option will work
in a specific application. Both process and equipment
changes need to be assessed for their overall effects
on waste quantity and product quality. ;
An economic evaluation is carried out using stan-
dard measures of profitability, such as payback period,
return on investment, and net present value. As in
any project, the cost elements of a waste minimization
project can be broken down into capital costs and
operating costs. Savings and changes in revenue and
waste disposal costs also need to be considered, as do
present and future cost avoidances. In cases of
increasingly stringent government requirements,
actions that increase the cost of production may be
necessary.
IMPLEMENTATION PHASE
An option that passes both technical and economic
feasibility reviews should be implemented. The proj-
ect can be turned over to the appropriate group for
execution while the WMOA team, with management
support, continues the process of tracking wastes and
identifying other opportunities for waste minimization.
Periodic reassessments may be conducted to see if the
anticipated waste reductions were achieved. Data can
be tracked and reported for each implemented idea in
terms such as pounds of waste per production unit.
Either initial investigations of waste minimization
opportunities or the reassessments can be conducted
using the worksheets in this manual.
References
DHS. 1988. Waste Audit Study: Metal Finishing
Industry. Prepared by PRC Environmental Man-
agement, Inc. for Alternative Technology Section,
Toxic Substances Control Division, California
Department of Health Services.
USEPA. 1992. Facility Pollution Prevention Guide.
U.S. Environmental Protection Agency, Office of
Research and Development, Washington, D.C.,
EPA/600/R-92/088.
USEPA. 1988. Waste Minimization Opportunity
Assessment Manual. U.S. Environmental Protec-
tion Agency, Hazardous Waste Engineering Re-
search Laboratory, Cincinnati, EPA/625/7-88/003.
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SECTION 2
METAL FINISHING INDUSTRY PROFILE
Industry Description
The metal finishing industry uses a wide variety of
materials and processes to clean, etch, and plate
metallic and nonmetallic surfaces to provide desired
surface properties. The materials include solvents and
surfactants for cleaning, acids and bases for etching,
and solutions of metal salts and other compounds to
plate a finish onto a substrate. Physical, chemical,
and electrochemical processes are all used to finish
metal workpieces. The processes may simply polish
the surface to provide a bright appearance or apply
another metal to change the surface properties or
appearance.
Process Description
Physical processes used in the metal finishing
industry—such as buffing, abrasive blasting, grinding,
tumbling, and polishing—do not generate as much
waste as chemical and electrochemical processes.
Physical processes involve the use of a solid material
(or abrasive) to change the surface characteristics of a
workpiece, and the waste generated contains the
abrasive and the material removed from the surface.
The use of sand for paint stripping operations is an
example of a physical finishing process. :
The industry also uses chemical processes (degreas-
ing, cleaning, pickling, etching, coating, and electro-
less plating) and electrochemical processes (plating,
electrocleaning, electropolishing, and anodizing).
These operations are typically performed in baths
(tanks) and are then followed by a rinsing cycle. Fig-
ure 2 illustrates a typical chemical or electrochemical
process step in which the workpiece enters the process
bath containing process chemicals that are carried to
the rinse water (drag-out). When the workpiece is
transferred from the bath to the rinse, process solution
will fall to the floor unless it is captured and returned
to the process bath. In such cases, waste can be mini-
mized by containing the process solution and returning
it to the bath, which reduces the rinse flow and
extends the life of the bath.
Workpiece
Vapors/Mist
(To Exhaust Scrubbers)
> i
Process
Chemicals
Process
Bath
Workpiece
Chemical Drag-Out
(To Floor and
Rinse System)
Workpiece
To Next Step
Rinse
System
Waste
Water
Fresh Water
Spent Bath
(Waste)
Figure 2. Typical Metal Finishing Process Step
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Waste Description
Wastewater, solid waste, and air emissions are
generated by the metal finishing process. Wastewater
includes:
• Industrial wastewater—rinse water, cooling
water, steam condensate, boiler blowdown,
wash water, and exhaust scrubber solution
• Spent plating baths—contaminated or spent
electroplating or electroless plating baths
• Spent process baths—etchants and cleaners that
are contaminated or spent
• Strip and pickle baths—nitric, sulfuric, hydro-
chloric, and hydrofluoric acids used to , strip
metals from workpiece racks or parts
• Exhaust/scrubber solutions—solutions collected
in exhaust and air emission control devices.
Solid waste includes:
• Industrial wastewater treatment sludge—sludge
containing metals such as cadmium, copper,
chromium, nickel, tin, and zinc
• Miscellaneous solid wastes—absorbants, filters,
empty containers, aisle grates, and abrasive
blasting residues
• Solvents—contaminated solvents used for
decreasing.
Air emissions include vapors from degreasing; and
solvent cleaning and mists from chromium plating
operations.
The primary source of waste in the metal finishing
industry occurs in the rinsing operation. Generally,
rinse water waste contains low concentrations of pro-
cess chemicals carried with the workpiece into the
rinse (drag-out). Typical rinse water treatment pro-
duces a metal hydroxide sludge that can be a hazard-
ous waste. Characterizing the drag-out carried into
the rinse water from the process bath requires the
chemical concentration and volume to be determined.
The chemical concentration of the drag-out is the
same as the chemical concentration of the process
bath; drag-out volume can be determined by measur-
ing the chemical concentration of a static rinse tank
before and after a loaded workpiece rack is rinsed.
The equation for calculating drag-out is as follows:
V '- (Cr) (Vr)
d g-
where Vd = volume of drag-out loss
Vr = volume of water in the rinse tank
Cp = concentration of chemicals in the pro-
cess bath
Cr = concentration of chemicals in the rinse
water.
After use, spent baths may be containerized for
treatment and disposal or recycled. To determine the
potential for modifying the bath's operating parame-
ters or recycling or reusing the bath, its chemical and
physical characteristics must first be quantified. The
characteristics establish the potential for the baths
reuse or value to a recycler.
Additional potential waste hazards in the metal fin-
ishing industry include vapors and mists emitted from
process baths, spills, and samples. Vapors and mists
are usually controlled by exhaust systems that must be
equipped with mist collection and scrubbing systems
to meet air emission regulations. Spills, if they are
common, can contribute significantly to the volume of
waste. Documenting their occurrence will provide
valuable historical information for identifying mainte-
nance or operational changes necessary to reduce then-
frequency. Samples of plating solutions provided by
vendors that are not intended for use also contribute to
the waste generated by the metal finishing industry.
These samples often accumulate without concern for
violating any waste storage time requirements. How-
ever, these samples must eventually be returned or
disposed of. Outdated chemicals are additional exam-
ples of waste not typically attributed directly to the
production process. Additional processing waste
includes the filter elements from filtration units, empty
process solution containers, abrasive blasting residues,
and waste from housekeeping activities. Table 1 is a
summary of the waste generated by the metal finish-
ing industry.
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Table 1. Summary Table pf Metal Finishing Industry Waste
Waste
Alkali (hydroxide)
Acid (nitric, sulfuric,
Potential
Hazards
Corrosivity
Corrosivity
Waste Stream
Wastewater
Wastewater
Process
Cleaning, etching
Cleaning, pickling,
hydrochloric,
hydrofluoric)
Surfactants
Oil and Grease
Cadmium, Zinc, Nickel,
Copper, Other Metals
Perchloroethylene,
Trichloroethylene,
Other Solvents
Cyanide
Chromates
Water
Aquatic toxicity
Aquatic toxicity
Toxicity
Inhalation, dermal
Toxicity
Toxicity
Wastewater
Wastewater, spent solvent
Plating bath, drag-out,
rinse water, spent filters,
sludge
Spent solvent (liquid or
sludge), air emissions
Plating bath, drag-out,
rinse water, other
wastewater
Plating bath, drag-out,
rinse water, sludge, other
wastewater, mist
Rinse water, drag-out, pro-
cess bath, air emission
(evaporation), cooling
water, boiler blowdown
etching, bright dipping
Cleaning
Cleaning
Plating
Cleaning
Plating, tumbling, strip-
ping, heat treating,
desmutting
Plating, chromating,
etching
Various
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SECTIONS
WASTE MINIMIZATION OPTIONS FOR
METAL FINISHING FACILITIES
Introduction
The three key elements in any waste reduction
program arc management initiative, commitment, and
involvement These prerequisites include activities
such as:
• Employee awareness and participation
• Improved operating procedures
• Employee training
• Improved scheduling of processes.
Employee training, awareness, and participation
are critically important and potentially problematic
aspects of metal finishing waste minimization pro-
grams. Employees are often resistant to broadening
their roles beyond the traditional concepts of quantity
and quality of products produced. Total commitment
and support of both management and employees are
needed for any waste minimization program to suc-
ceed. This includes the evaluation, development,
implementation, and maintenance of a system to mini-
mize waste.
Companies should continually educate themselves
to keep abreast of improved, waste-reducing, pollu-
tion-preventing technology. Information sources to
help inform companies about such technology include
trade associations and journals, chemical and equip-
ment suppliers, equipment expositions, conferences,
and industry newsletters. By implementing better
technology, companies can often take advantage of the
dual benefils of reduced waste generation and a more
cost efficient operation.
The specific approaches recommended for waste
minimization for metal finishing facilities include
source reduction and recycling/resource recovery.
Source reduction technologies are designed to reduce
the volume of waste initially generated. In recycling
and resource recovery, waste is used as a raw material
for the same or another process or valuable materials
are recovered from a waste stream before the waste is
disposed of. This section provides detailed informa-
tion on the two approaches for waste minimization in
the metal finishing industry.
Source Reduction
Source reduction approaches decrease the amount
of generated waste, and they are usually the least
expensive method of minimizing waste. Many source
reduction options require only simple housekeeping
changes or minor in-plant process modifications.
Source reduction opportunities for process baths and
rinse systems are described below. In addition,
improved housekeeping methods for achieving source
reduction are discussed.
PROCESS BATHS
Source reduction for the metal finishing industry
at the process bath level can be achieved by material
substitution, extending bath life, and drag-out
reduction.
Material Substitution ,
Pollution control regulations have provided the
incentive for using less toxic process chemicals, and
chemical manufacturers are gradually introducing such
substitutes. Eliminating process materials, such as
hexavalent chromium and cyanide-bearing cleaners
and deoxidizers, eliminates the need to detoxify these
wastes. It is particularly desirable to eliminate pro-
cesses employing hexavalent chromium and cyanide,
since special equipment is needed to detoxify both.
Because there can be disadvantages in substituting
one process chemical for another, the following ques-
tions should be asked:
• Are substitutes available and practical?
• Will substitution solve one problem but create
another?
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• Will tighter chemical controls be required of
the bath?
• Will product quality or production rate be
affected?
• Will the change involve any cost increases or
decreases?
Most opportunities to reduce waste by substituting
materials require modifying the chemistry of process
baths or replacing the chemicals used for a particular
process. Since process bath chemistries vary widely
from plant to plant, these options can only .be
described in general terms.
Purified Water. Deionized, distilled, or reverse
osmosis water can be used instead of tap water for
process bath makeup and rinsing. Natural contami-
nants, such as calcium, iron, magnesium, manganese,
chlorine, carbonates, and phosphates (found in tap
water) reduce rinse water efficiency, interfere with
drag-out recovery, and increase the frequency of pro-
cess bath dumping (USEPA 1982b). These contami-
nants also contribute to sludge volume when they are
removed from wastewater during treatment.
Hexavalent Chromium Alternatives. Trivalent
chromium plating solutions can be used for decorative
chromium plating to replace hexavalent chromium. In
so doing, drag-out is decreased because trivalent
chromium plating baths operate with a lower viscosity
and lower concentration than do hexavalent baths.
The use of trivalent chromium also eliminates an extra
treatment step necessary to reduce the chromium from
the hexavalent to trivalent state before precipitation.
In addition, using trivalent chromium eliminates the
problems associated with hexavalent chromium bath
misting as well as hexavalent chromium fugitive emis-
sions in air scrubbers. However, trivalent chromium
is not presently available for hard chromium plating
(AESF 1991). Other chromium alternatives include
sulfuric acid and hydrogen peroxide (for chromic acid
pickles, deoxidizers, and bright dips) and benzotria-
zole (0.1 to 1.0 percent solution in methanol) or
water-based proprietaries (for chromium based anti-
tarnish). The latter two alternatives are extremely
reactive and require ventilation.
Nonchelated Process Chemicals. Chelators are
used in chemical process baths to control the concen-
tration of free metal ions in the solution. They are
usually found in baths used for metal etching, clean-
ing, and electroless plating. When chelating com-
pounds enter the waste stream, they inhibit the precip-
itation of metals so that additional treatment chemicals
must be used, and these treatment chemicals may end
up in the sludge and contribute to the volume of haz-
ardous waste. For example, when ferrous sulfate, a
popular precipitant, is used to precipitate metals from
chelated complexes, the precipitant adds significantly
to sludge volume. For some applications, the ferrous
sulfate is added in large amounts, at an 8-to-l ratio to
the contaminant metals (Couture 1984). If spent pro-
cess baths containing chelators cannot be treated on
site, they must be containerized for off-site treatment
or disposal, which increases waste disposal costs.
Several chelators are used in metal finishing
industry processes. In general, mild chelators such as
phosphates and silicates are used for cleaning and
etching processes, whereas electroless plating baths
are typically chelated with stronger chelating com-
pounds (citric acid, maleic acid, and oxalic acid).
Ethylenediaminetetraacetic acid (EDTA) is also used
but with less frequency than the others (Kraus 1988).
It should be noted, however, that while chelators help
extend bath life, chelated process chemicals in waste-
water must be removed to required discharge levels.
Often, the pH of waste streams must be adjusted to
break down the metal complexes that chelators form.
EDTA, for example, requires lowering the pH below
3.0 to break the complex and allow subsequent metal
precipitation at high pH (Foggia 1987).
Nonchelated process chemistries can be used for
some processes (e.g., alkaline cleaning and etching) in
which it may not be necessary to keep the metals
removed from workpiece surfaces in solution. In
these cases, the metals can be allowed to precipitate,
and the process bath can be filtered to remove the
solids. Note, however, that for electroless plating, it
is less feasible to use nonchelated chemistries because
the chelators play a significant role in the chemical
processes that allow the plating bath to function
(Kraus 1988).
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Nonchelated process cleaning baths usually
require continuous filtration to remove the solids that
form. These systems generally have a 1- to 5-micron
filter with a pump that can filter the tank's contents
once or twice each hour (Foggia 1987). The cost'of a
filter system ranges from approximately $400 to
$1,000 for each tank, and in addition to purchase: and
setup costs, costs will be incurred for filter element
replacement, disposal, and maintenance.
Savings, however, will be realized in reduced
waste treatment and sludge handling costs and reduced
disposal costs for spent baths. Another important
advantage of nonchelated process chemicals is that the
metal-removal procedure during wastewater treatment
is usually improved. Therefore, the treated effluent is
more likely to meet discharge requirements. \
Noncyanide Process Chemicals. An alkaline
chlorination process requiring sodium hypochlorite or
chlorine is typically used to treat waste streams bon-
taining free cyanide. If complex cyanides are tp be
treated, ferrous sulfate precipitation is commonly used.
These chemicals contribute to sludge volume. There-
fore, using noncyanide process chemistries niay
reduce hazardous waste sludge by eliminating a treat-
ment step. However, many noncyanide processes are
difficult to treat and produce more sludge than cya-
nide baths. The following paragraphs provide exam-
ples and include advantages and disadvantages of
each. The user should weigh the advantages and: dis-
advantages for specific applications.
The waste water treatment savings will depend on
the cyanide treatment method and the volume of
waste. Cyanide is typically oxidized with sodium or
calcium hypochlorite. These chemicals cost approxi-
mately $1.50 per gallon of solution for sodium hypo-
chlorite and approximately $1.85 per pound for cal-
cium hypochlorite powder. Assuming that a facility
treats 500 gallons of dilute cyanide waste (100 mg/1)
each day, treatment costs could be approximately; $15
to $20 per day or $300 to $400 per month (not includ-
ing subsequent metal precipitation and sludge dispos-
al).
The use of noncyanide plating baths could elimi-
nate or reduce this cost. For a 2 gal/min rinse water
flow, using noncyanide baths means a savings of
about $12,000 in equipment costs and $3.00/lb in cya-
nide treatment chemical costs. (In this case, treatment
chemicals cost about four times as much as raw
sodium cyanide cleaner.)
Alternatives to cyanide cleaners include trisodium-
phosphate or ammonia; both provide good degreasing
when used hot in an ultrasonic bath. However, they
are highly basic and may complex with soluble metals
if used as an intermediate rinse between plating baths
where metal ions may be dragged into the cleaner.
Alternatives to cyanide plating bath chemistries
are also available. Acid tin chloride, for example,
works faster and better than tin cyanide. In contrast
to a heavy copper cyanide plating bath, copper sulfate
baths are highly conductive and have a simple chemis-
try. Sulfate baths are economical to prepare, operate,
and treat. Previous sulfate bath problems have been
overcome with new formulations and additives (Metal
Finishing, 1989). The copper cyanide strike may still
be needed for steel, zinc, or tin-lead base metals. One
disadvantage of alternatives to cyanide plating bath
chemistries is that noncyanide chemistries often cost
more than conventional cyanide baths.
Alkaline Cleaners. A variety of chlorinated and
nonchlorinated solvents are used to degrease work-
pieces before they are processed. These solvents can
be either recycled on site or transported off site for
recycling or disposal. On-site recycling generates a
solvent sludge that is disposed of off site. However,
using hot alkaline cleaning baths instead of solvents
permits the baths to be treated on site and discharged
to certain publicly owned treatment works (AESF
1991), and less sludge is generated than by solvent
degreasing. The effectiveness of alkaline cleaners can
be enhanced by applying an elecirocurrent, a periodic
reverse current, or ultrasonics. The benefits of avoid-
ing solvent vapors and sludges often outweigh any ad-
ditional operating costs.
A 150-gallon tank to hold the alkaline cleaning
solution will cost approximately $400; tank installa-
tion, a heating system, ventilation, and an oil separa-
tion system would increase the cost to an estimated
$6,000. The cost of chemicals depends on the type of
cleaners used and the frequency of replacement Typ-
ically, alkaline cleaners cost less than degreasing sol-
vents. A standard degreasing solvent costs between
$6 and $13 per gallon, or $300 to $700 to fill a
10
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50-gallon degreasing tank, whereas, a ISO-gallon-
alkaline cleaning bath (using sodium hydroxide) costs
$150 to $200. However, the life of an alkaline clean-
ing bath typically is shorter than that of a solvent
degreasing solution: a 50-gallon tank of solvent
degreaser can last up to 6 months, whereas a
ISO-gallon replacement of alkaline cleaner usually
lasts 3 months under similar operating conditions or
longer than 3 months with bath maintenance and
filtration.
Disposing of a 55-gallon drum of spent solvent
can cost from $300 to $1,200, depending on the type
of solvent and number of drums. Therefore, if a facil-
ity can treat 300 gallons of spent alkaline solution on
site using pH adjustment and metal removal
(ISO-gallon bath replaced every 3 months) and dispose
of the resultant sludge for less than the cost of solvent
disposal, it would be economically feasible to replace
a degreasing solvent with an alkaline cleaner.
Alternative Cleaners. Biodegradable cleaners may
be acceptable for discharge to public sewers. How-
ever, the oxygen demand created by the cleaners dur-
ing treatment and disposal of the bath may slightly
increase sewer fees. Nonphosphate cleaners may help
reduce waste by eliminating the generation of phos-
phate sludges during wastewater treatment. These and
other alternative cleaners should be tested to deter-
mine their effectiveness.
Bath Life Extension
When baths become spent, they are either taken
off line and treated on site or are placed in containers
for off-site disposal. Waste volume and bath replace-
ment costs can be decreased through filtration, replen-
ishment, electrolytic dummying (i.e., using a low
current to plate out contaminants), precipitation, moni-
toring, housekeeping, drag-in reduction, purer anodes
and bags, and ventilation/exhaust systems. These
methods of extending bath life are described below.
Filtration. Filtration systems remove accumulated
solids that reduce the effectiveness of the process bath
operations. Continuous filtration of the bath removes
these contaminants, thereby extending the life of the
bath. Many acidic electroplating baths (e.g., acid cop-
per sulfate, acid zinc, nickel sulfonate, nickel chloride)
are already filtered for reasons of quality. . For other
electroplating baths, filtration may not extend bath life
significantly. Note that replacing the filter media
generates a solid waste that adds to the operating
costs; these costs need to be considered before install-
ing a filter. However, some filters use a cleanable
and reusable filter media, which may help alleviate
expense and waste from disposal of the filter element.
Replenishment. The effectiveness of a cleaning
bath decreases with use. Instead of disposing of the
entire bath, part can be retained and replenished with
fresh chemicals and water. Over time, the concen-
tration of contaminants in the bath increases, and
eventually it becomes more expensive to add chemi-
cals than to replace the entire bath with a new solu-
tion. At this point the bath should be disposed of.
Replenishing reduces drag-out in the early life of
the bath, but ultimately increases the concentrations of
chemicals in spent solutions when the bath must be
replaced. Although this approach does not ultimately
reduce drag-out, it is still justifiable on the basis of
quality control and waste reduction.
There are various automated bath monitoring and
replenishing systems now available to help extend
bath life. Operators can use data generated by bath
monitoring systems to manually adjust and maintain
process bath characteristics, such as pH, chemical con-
centration, and metal content, within specifications, to
improve product quality and to extend bath life. Both
replenishing and adjusting can also be done using
automated systems.
Electrolytic Dummying. Metal contaminants (such
as copper) introduced into plating baths with work-
pieces degrade the effectiveness of the plating process.
In zinc and nickel baths, copper can be removed by a
process called "dummying." The process is based on
the electrolytic principle that copper can be plated at a
low electrical current. When the copper content
becomes too high, an electrolytic panel is placed in
the process bath. A "trickle current" is run through
the system, usually at a density of 1 to 2 amperes per
square foot. At this current, the copper in the bath
solution plates out on the panel, but the plating bath
additives (such as brighteners) are unaffected. While
some of the plating metals (zinc, nickel) are inadver-
tently removed, the savings realized by extending bath
life justifies the slight metal loss. ,
11
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Precipitation. Metals such as lead and cadmium
enter the bath as impurities in anodes and can be
removed from certain plating baths by precipitation.
For a zinc cyanide bath, zinc sulfide can be added to
precipitate lead and cadmium, and the precipitant can
then be removed by filtration. As with all cheihical
reactions, care must be taken to ensure that precipita-
ting reagents are compatible with bath constituents. In
addition, iron and chromium contamination is common
in acidic nickel baths. In most solution formulations,
these metals can be removed with peroxide combined
with pH elevation and batch filtration.
Monitoring, The key to determining the need for
added chemicals or removal of contaminants, and
hence extending the life of process bath, is the contin-
uous analysis of bath parameters, e.g., pH and metal
content. In addition, a thorough understanding of the
effect of contaminants on the production process is a
critical part of reducing waste as well as the number
of rejected parts that must be stripped and replated.
Monitoring must be treated as an ongoing process, not
an event.
Housekeeping. Preventing foreign material from
entering or remaining in a bath prolongs its :life.
When a part falls off the rack into a bath, it should be
removed to reduce contamination of the bath. The
racks should also be kept clean and free of contami-
nating material. Other waste minimization measures
include protecting anode bars from corrosion, using
corrosion-resistant tanks and equipment, and filtering
incoming air to reduce airborne contaminants.
Drag-In Reduction. Liquids clinging to work-
pieces from preceding baths can shorten useful life
and reduce effectiveness of subsequent baths. Rinsing
helps prevent cross-contamination between baths by
rinsing the drag-out from one process bath before the
item is processed in another.
Purer Anodes and Bags. Impurities contained in
anodes will contaminate a process bath. Pure anodes
do not contribute to bath contamination, but may cost
more than other, less-pure anodes. Cloth bags around
anodes prevent insoluble impurities from entering a
bath. However, the bags need to be maintained and
must be compatible with the process solution.
Ventilation/Exhaust Systems. Scrubbers, demist-
ers, and condensate traps remove entrained droplets
and vapors from the air passing through ventilation
and exhaust systems. If segregated, some wastes from
scrubbers can be returned to process baths after filter-
ing. Updraft ventilation allows mist to be collected in
the ductwork and flow back to the process tank. For
example, hard chromium plating baths would benefit
from an updraft ventilation system.
Process baths that generate mist (e.g., hexavalent
chromium plating baths, air-agitated nickel/copper
baths, etc.) should be in tanks with more freeboard to
reduce the amount of mist reaching the ventilation
system. That is, the added space at the top of the
tank allows the mist to return to the bath before it is
entrained with the air entering the exhaust system.
Foam blankets or floating polypropylene balls can also
be used in hard or decorative chromium baths to keep
mists from reaching the exhaust system.
Drag-out Reduction
Several factors contribute to drag-out, including
workpiece size and shape, viscosity and chemical con-
centration, surface tension, and temperature of the
process solution (USEPA 1982a). By reducing the
volume of drag-out that enters the rinse water system,
valuable process chemicals can be prevented from rea-
ching the rinse water, thereby reducing sludge gen-
eration. The techniques available to reduce process
chemical drag-out include:
• Minimizing bath chemical concentrations by
maintaining chemistry at the lower end of
operating range
• Maximizing bath operating temperature to
lower the solution viscosity
• Using wetting agents in the process bath to
reduce the surface tension of the solution
• Maintaining racking orientations to achieve the
best draining
• Withdrawing workpieces at slower rates and al-
lowing sufficient solution draining before
rinsing
12
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• Using air knives above process tanks
• Using a spray or fog rinse above process tanks
• Avoiding plating bath contamination
• Using drain boards between process and rinse
tanks to route drippage back to process tanks
• Using drag-out tanks to recover chemicals for
reuse in process baths.
A few of these drag-out reduction techniques
require little if any capital investment; however, they
do require training. For example, removing workpiece
racks at a slower rate or allowing the rack to drain
over the process tank for a longer time requires a con-
scientious operator. These procedures should not sig-
nificantly affect production and should result in reduc-
ing process chemical purchases, water and sewer use
fees, treatment chemical purchases, and sludge hand-
ling costs.
Other drag-out reduction techniques require some
capital expenditure. Drip bars can be installed above
hand-operated process tanks to allow drag-out from
workpiece racks to drain back into the process tank.
If PVC piping is used and installation is performed by
plant personnel, this option should cost no more than
a few hundred dollars for five to eight tanks.
Process Bath Operating Concentration. Drag-out
can be reduced by keeping the chemical concentration,
of the process bath at the lowest acceptable operating
level. Generally, the greater the concentration of
chemicals in a solution, the greater the viscosity
(USEPA 1982a). As a result, the film that adheres to
the workpiece as it is removed from the process bath
is thicker and will not drain back into the process bath
as quickly. This phenomenon increases the volume as
well as the chemical concentration of the drag-out
solution.
Chemical product manufacturers may recommend
an operating concentration that is higher than neces-
sary. Metal finishers should therefore determine the
lowest process bath concentration that will provide
adequate product quality. This can be accomplished
by mixing a new process bath at a slightly lower
concentration than is normally used. As the process
bath is replenished, the chemical concentration can
continue to be reduced until product quality begins to
be affected. At this point, the process bath that pro-
vides adequate product quality at the lowest possible
chemical concentration is identified. Alternatively, the
new bath can be mixed at a low concentration and the
concentration can be gradually increased until the bath
adequately cleans, etches, or plates the test work-
pieces. Fresh process baths can often be operated at
lower concentrations than used baths. Makeup chemi-
cals can be added to the used bath to gradually
increase the concentration to maintain effective
operation.
Process Bath Operating Temperature. Higher
temperature baths reduce the viscosity of the process
solution, which enables the chemical solution to drain
from the workpiece faster, thereby reducing drag-out
loss. However, very high temperatures should be
avoided because brighteners break down in most plat-
ing solutions, and, in cyanide solutions, carbonate
buildup increases. High temperatures'may also cause
the process solution to dry onto the workpiece as it is
removed, increasing drag-out. Operating process
baths at higher temperatures will also increase the
evaporation rate from the process tank. To retain
some of the advantages of higher temperature baths,
water or process solution from a rinse tank can be
added to replenish the process bath and to maintain
the proper chemical equilibrium. Deionized water
should be used to minimize natural contaminant
buildup (such as calcium, iron, magnesium, carbonates
and phosphates) in the process bath.
Wetting Agents. Adding wetting agents to a pro-
cess bath reduces the surface tension of a solution
and, as a result, can reduce drag-out loss by as much
as 50 percent (USEPA 1982a). However, wetting
agents can create foaming problems in process baths
and may not be compatible with waste treatment sys-
tems. For these reasons, impacts at both the process
bath and the treatment system should be evaluated be-
fore using wetting agents.
Workpiece Positioning. Drag-out loss can be
reduced by properly positioning the workpiece on the
rack. Workpieces should be oriented so that chemical
solutions can drain freely and not get trapped in
13
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grooves or cavities. Following are suggestions for
orienting and positioning workpieces.
• Parts should be tilted so that drainage is con-
solidated. The part should be twisted or turned
so that fluid will flow together and off the part
by the quickest route.
i
• Avoid, where possible, positioning parts
directly over one another.
• Tip parts to avoid table-like surfaces and pock-
ets where solution will be trapped.
• Position parts so that only a small surface area
comes in contact with the solution surface jas it
is removed from the process bath (USEPA
1982a). :
Withdrawal and Drain Time. The faster an item
is removed from the process bath, the thicker the;film
on the workpiece surface and the greater the drag-out
volume. The effect is so significant that it is believed
that most of the time allowed for draining a jrack
Should instead be used for withdrawal only (USEPA
1982a). At plants that operate automatic hoist lines,
personnel should adjust the hoist to remove the Work-
piece racks at the slowest possible rate. However,
when workpieces are removed from a process 'bath
manually, it is difficult to control the speed at which
they are withdrawn. Nevertheless, supervisors and
managers should emphasize to process line operators
that workpieces should be withdrawn slowly.
The time allowed for draining can be inadequate
if the operator is rushed to remove the workpiece jrack
from the process bath and place it in the rinse tank.
However, a bar or rail above the process tank Imay
help ensure adequate drain time prior to rinsing! If
drip bars are used, employees can work on more [than
one process line or handle more than one rack during
operation. The practice, termed "rotation plating,':" al-
lows an operator to remove a rack from a plating bath
and let it drain above the process tank while Other
racks are handled. Although increased drain time can
have some negative effects due to drying, some baths
(such as cleaners) are not affected. The operator can
return after draining is completed to begin the rinsing
stage.
Air Knives. Air knives can be used above process
tanks to improve draining. As the workpiece rack is
raised from the process tank, air is blown onto the
surface of the workpieces to improve drag-out solution
draining into the process bath. High humidity air can
counteract workpiece drying.
Spray or Fog Rinses. Spray or fog rinse systems
can be used above heated baths to recover drag-out
solutions. If the spray rinse flow rate can be adjusted
to equal the evaporation loss rate, the spray rinse solu-
tion can be used to replenish the process bath. Puri-
fied water should be used for the spray systems when
possible to reduce the possibility of contamination
entering the bath with the spray rinse water.
Plating Baths. Contaminated plating baths (for
example, a cyanide plating bath contaminated with
carbonate) increase drag-out by as much as 50 percent
because of the increase in solution viscosity. Excess
impurities also make application of recovery tech-
niques difficult, if not impractical. Therefore, efforts
should be made to reduce the level of impurities in
the bath (e.g., by carbonate removal in cyanide baths).
Drain Boards. Drain boards capture process
chemicals that drip from the workpiece rack as it .is
moved from the process bath to the rinse system. The
board is mounted at an angle that allows the chemical
solution to drain back into the process bath. Drain
boards should cover the space between the process
bath tank and the rinse tank. This prevents chemical
solutions from dripping onto the floor. Removable
drain boards are desirable because they permit access
to plumbing and pumps between tanks.
Drag-out Tanks (dead or static rinse tanks).. Pro-
cess chemicals that adhere to the workpiece can be
captured in drag-out tanks and returned to the process
bath.' Drag-out tanks are essentially rinse tanks that
operate without a continuous flow of feed water. The
workpiece is placed in the drag-out tank before the
standard rinsing operation. Chemical concentrations
in the drag-out tanks increase as workpieces are
passed through. Since there is no feed water flow to
agitate the rinse water, air agitation is often used to
enhance rinsing. Eventually, the chemical concentra-
tion of the drag-out tank solution will increase to the
point where it can be used to replenish the process
14
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bath. Drag-out tanks are primarily used with proeess
baths that operate at an elevated temperature. Add-
ing the drag-out tank solution back to the process bath
compensates for evaporative losses that occur due to
high temperature.
Deionized water should be used for drag-out tanks
so that natural contaminants in tap water do not build
up in the process baths when drag-out solutions are
used to replenish them. Contamination as a result of
using the tank to rinse a workpiece from another pro-
cess line must also be avoided. Further, adding drag-
out solution to some process bath chemistries (for
example, electroless copper baths) can adversely affect
the bath (Stone 1987). Often, a pretreatment step is
required to remove contaminants prior to adding the
recovered drag-out solution back to the process bath.
Generally, a drag-out tank can reduce both rinse
water use and chemical loss by 50 percent or more
(USEPA 1982a). Assuming that a chemical bath loses
approximately 2 gallons of drag-out each day, the total
volume of drag-out loss each month would be 40 gal-
lons, based on 20 work days per month. If the rinse
system following the proeess bath operates at a flow
rate of 5 gallons per minute, for a total of 4 hours
each day, water usage would be 24,000 gallons per
month based on 20 work days per month. The sav-
ings in operation expenses are for (1) raw materials/
chemicals, (2) water and sewer fees, and (3) treatment
chemicals and sludge disposal. Reducing drag-out and
rinse water use by 50 percent would reduce chemical
losses by 20 gallons per'month and water usage by
12,000 gallons if rinse water reduction is proportional
to drag-out reduction. If water and sewer fees are
each $0.50 per 100 cubic feet, 16 dollars per month
could be saved. Sludge reduction and raw material/
chemical reduction would increase savings signifi-
cantly. The solution collected in the drag-out. tank
must be returned to the process bath when the concen-
tration of the solution reaches the correct level. If it
is returned at too low a concentration, it can dilute the
operating bath. If the concentration of chemicals in
the drag-out tank gets too high (approaching bath con-
centration), however, the drag-out rinse becomes inef-
fective.
Savings for chemicals depends on the type of pro-
cess chemical and the amount of drag-out returned to
the process tank. The cost for process bath chemicals
could range from less than $1 to over $20. At the
low end, the savings for process chemicals would be
$20 per month, whereas,-at the high end, the savings
would be $400 per month or higher.
A savings in the cost for treatment chemicals
would also be realized by reducing rinse water efflu-
ent. If a company spends approximately $1,500 each
month on chemicals to treat 200,000 gallons of water,
reducing wastewater by 12,000 gallons could reduce
the use of treatment chemicals by $90 each month.
This assumes the company generates approximately
10,000 gallons of wastewater per day and uses stan-
dard pH adjustment, metal precipitation, and floccula-
tion treatment reagents. Reducing the amount of
sludge requiring disposal will add to the savings.
The cost of a drag-out tank depends on the size of
the tank. Since these tanks are not used as flow-
through tanks, they can be set up without any plumb-
ing. Typically drag-out solutions are added back to
the process bath manually, but automation, because it
maintains the best concentration in the drag-out tank,
is more efficient. Technologies available to recycle
process chemicals from drag-out tanks and rinse water
effluent are discussed under Recycling and Resource
Recovery.
RINSE SYSTEMS
Most hazardous waste from a metal finishing plant
comes from wastewater generated by the rinsing oper-
ations that follow cleaning, plating, and stripping
operations. The savings associated with reducing
rinse water use are primarily from reduced water,
sewer, and sludge disposal fees. By increasing rinse
efficiency, a process line can reduce wastewater flow
by as much as 90 percent (Watson 1973, Gavaskar
et al. 1992). Improved rinse efficiency should also
reduce treatment chemical use and sludge generation.
These are dependent on rinse water hardness and the
sludge precipitation chemicals used in the wastewater
treatment system.
If a company spends approximately $400 each
month for water and sewer fees, a modest reduction in
rinse water usage of 10 percent can, :theoretically, save
the company $40 each month. If a 2-year payback on
investment is acceptable, the company could justify
spending approximately $1,000 to reduce its rinse
water usage. This could be spent on rinse tank agita-
tors and flow restrictors. If greater reductions are
15
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achievable (perhaps 50 percent), a company could jus-
tify more advanced technologies such as mete^ con.-
trolling rinse water flow or counter-current rinse sys-
tems. Reducing the volume of wastewater requiring
treatment can also reduce sludge disposal costs and
treatment chemical use, which will contribute to the
payback on investment.
Drag-out is the most significant source of prbcess
chemical loss. Treating rinse water containing :these
process chemicals generates hazardous waste because
of the resulting sludge. The volume of sludge gener-
ated is proportional to the level of contamination in
the spent rinse water.
Figure 3 illustrates the relationship between metal
concentration in rinse water and sludge volume. The
graph shows the percentage of sludge generated per
volume of water treated at various levels of heavy
metal concentration. As shown in the graph,
1,000 gallons of wastewater with a heavy metal1 con-
centration of 100 mg/1 will produce approximately
90 gallons of sludge. If the same volume of waste-
water had a 'metal concentration of 500 mg/L (five
times the first example), approximately 280 gallons of
sludge would be generated, not even three times the
first example. This information indicates that treating
a more concentrated waste stream results in less
sludge volume.
Reducing the volume of rinse water containing
process chemicals will reduce the resultant sludge
even if the total weight of the process chemicals
remains constant. Two techniques available for reduc-
ing rinse water volume are improved rinse efficiency
and rinse water flow control.
Improved Rinse Efficiency
The following three strategies can be used to
enhance rinsing between various process bath opera-
tions: (1) turbulence between the workpiece and the
30
20
10
I
I
I
100 200 300
Heavy Metal Concentration (mg/l)
400
500
Figure 3. Sludge Volume Generation
•Volume of sludge per volume of wastewater treated after 1 hour of settling. Treatment consists of lime neutralization.
Source: USEPA, Environmental Pollution Control Alternatives: Sludge Handling, Dewatering, and Disposal Alternatives for the
Metal Finishing Industry, October 1982.
16
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rinse water, (2) increased contact time between the
workpiece and the rinse water, and (3) increased vol-
ume of water during contact time to reduce the con-
centration of chemicals rinsed from the workpiece sur-
face (USEPA 1982a). The third strategy, however, re-
quires finishers to use significantly more rinse water
than is actually necessary. Spray rinsing, agitation,
increased contact time, rinse elimination, and counter-
flow multiple tank rinsing, on the other hand, can be
used to improve the efficiency of a rinsing system and
reduce the volume of rinse water.
Spray Rinses and Rinse Water Agitation. Turbu-
lence, which involves spray rinsing and rinse water
agitation, improves rinse efficiency. Although spray
rinsing uses between one-eighth and one-fourth the
volume of water that a dip rinse uses (USEPA 1982a),
it is not always applicable in metal finishing because
the spray rinse may not reach many parts of the work-
piece. However, spray rinsing can be combined with
immersion rinsing. This technique uses a spray rinse
as the first rinse step after the workpieces are
removed from the process tank. A spray rinse
removes much of the drag-out and returns it to the
process bath before the workpiece is submerged into
the dip rinse tank, permitting lower water flows in the
rinse tank.
Spray or fog rinses can be installed above heated
process tanks if the volume of rinse water from the
spray system is less than or equal to the volume of
water lost to heat evaporation. This practice allows
the drag-out and the rinse solution to drain directly
back into the process bath; in this way, the rinse solu-
tion replenishes the process bath. Deionized or
reverse osmosis water should be used in this type of
spray rinse system.
Workpieces can be agitated in the rinse water by
moving the workpiece rack or creating turbulence in
the water. Since most metal finishing plants operate
hand rack lines, operators could easily move workpie-
ces manually by agitating the hand rack. Rinsing is
more effective if the pieces are raised and lowered
into and out of the rinse tank rather than agitating the
pieces while they are submerged.
The rinse water can also be agitated with forced
air or water by pumping either air or water into the
immersion rinse tank. Air bubbles create the best tur-
bulence for removing the chemical process solution
from the workpiece surface (USEPA 1982a), but mist-
ing, as the air bubbles break the surface, may cause
air pollution. Filtered air can be pumped into the
bottom of the tank through a pipe distributor (air
sparger) to agitate the rinse water. An in-tank pump
can also recirculate the rinse water in the tank (a pro-
cess known as forced water agitation). An agitator
(mixer) can be used in a rinse tank, but this requires
extra room in the tank to prevent parts from touching
the agitator blades.
Air spargers, water pumps, or agitators can .be
installed in existing rinse tanks at a modest cost. The
cost of installing air spargers with a blower to provide
the air would be $200 to $325 for a 50-gallon tank.
Air blowers eliminate the air cleaners and filters
needed in compressed air systems to remove oils. An
in-tank pump for forced water agitation can be pur-
chased for $200 to $1,000, depending on the flow rate
desired.
Increased Contact Time. If multiple tanks are set
up in series as a counter-current rinse system, water
usage can be reduced and contact time between the
workpiece and the rinse solution can be increased.
Rotation plating also increases contact time by allow-
ing operators to leave workpiece racks in the rinse
tanks while they handle other racks. .
Rinse Elimination. The rinse between a soak
cleaner and an electrocleaner may be eliminated if the
two baths are compatible.
Counter-Current Rinse Systems. Multiple rinse
tanks can be used to significantly reduce the volume
of rinse water used. A multistage counter-current
rinse system uses up to 90 percent less rinse water
than a conventional single-stage rinse system (Couture
1984). In a multistage counter-current rinse system,
workpiece flow moves in a direction opposite to the
rinse water flow. Water exiting the first tank (the last
tank in which the workpiece is immersed) becomes
the feed water to the second tank. This water then
feeds the third tank, and so on for the number of
tanks in the line. Figure 4 illustrates the use of a
three-stage counter-current rinse system.
The effectiveness of this multistage system in
reducing rinse water use is illustrated in the following
17
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)
Workpiece
Movement
f
Process
Tank
Work
^ ^^ ^ Product
r. r. r.
Rinse Rinse Rinse
I i I
1 1 1
v ' ! i
V l-<- L<— ] Rinse
Effluent to Water
Recycle, Resource Influent
Recovery or Treatment '
Figure 4. Three-Stage Counter-Current Rinse System
example. A plant operates a process line where the
drag-out rate is approximately 1.0 gallon per hour.
This process bath is followed by a single-stage rinse
tank requiring a dilution rate of 1,000 to 1 to maintain
acceptable rinsing. Therefore, the flow rate through
the rinse tank is 1,000 gaVhr. If a two-stage counter-
current rinse system were used, a rinse water flowjrate
of only 30 to 35 gal/hr would be needed. If a three-
stage counter-current rinse system were used, only 8
to 12 gal/hr would be required (Watson 1973).
A multistage counter-current rinse system allows
greater contact time between the workpiece and the
rinse water, greater diffusion of process chemicals Into
the rinse solution, and more rinse water to come jinto
contact with the workpiece. The disadvantage of mul-
tistage counter-current rinsing is that additional tanks
and work space are needed. Since many metal finish-
ers lack room to install additional rinse tanks, mfolti-
stage rinse systems are not always feasible. One
option available to a metal finishing plant that lacks
floor space is to reduce the size of the rinse tanks or
to segregate existing tanks into multiple compart-
ments. This option is limited, however, by the size of
the workpieces.
Installing a counter-current three-rinse system into
an existing single-stage rinse system requires two
additional rinse tanks and the associated piping. The
cost would depend on the size of tanks. Assuming the
tanks have a capacity of 450 gallons, installation could
run approximately $1,200.
Flow Controls
Rinse water use is excessive if water pipes are
oversized or the water is left running when the rinse
tanks are not being used. Rinse water control devices
can increase the efficiency of a rinse water system.
The cost of reducing rinse water use varies
depending on the method. The cost may be limited to
that associated with purchasing and installing flow
restrictors or timers, Savings ;from reduced rinse
water flow rates include direct reduction of water use,
sewer fees, treatment chemical use, and sludge genera-
tion.
The following equation will assist in determining
the most efficient rinse water flow rate for a single-
stage rinse system:
18
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Q . D (Cp/Cn)
where
Q = rinse tank flow rate
D = drag-out rate
Cp = chemical concentration in process solution
Cn = allowable chemical concentration in rinse
solution (USEPA 1982a).
The value of Cn is based on experience or on quality
control standards.
The effect on rinse water flow rate for multiple
stage rinse tanks can be evaluated using another
equation: :
Q = [(Cp/Cn)1/n+ l/n]D
where :
n = number of rinse tanks in series (USEPA
1982a).
Flow Restrictors. Flow restrictors limit the vol-
ume of rinse water flowing through a rinse system by
maintaining a constant flow of fresh water once the
optimal flow rate has been determined. Since most
small- and medium-sized metal finishers operate batch
process lines in which rinse systems are manually
turned on and off at the start and finish of operations,
pressure-activated flow control devices, such as foot
pedal activated valves or timers, can be helpful to en-
sure that water is not left on after the rinse operation
is completed.
Installing a flow restrictor upstream of all, the
rinse water influent lines reduces water use. Setting
the flow restrictor at a rate less than the flow rate
required to operate all rinse tanks simultaneously
requires operators to turn off the water in the unused
rinse systems so the rinse systems in use will have
adequate flow. For example, if a metal finisher oper-
ates between 20 and 24 separate rinse systems, each
requiring an average flow rate of 2 gallons per minute
(gpm), a flow restrictor, installed upstream of all the
rinse water, influent lines, could limit total water flow
to 15 gpm. Therefore, operators: must turn off unused
rinse systems to ensure that the rinse systems requir-
ing immediate use will operate properly. It is impor-
tant to-note that operator training and complete coop-
eration are required for this type of system to work.
Otherwise parts will not be rinsed effectively and
product quality will decrease.
Conductivity-Actuated Flow Controller. A
conductivity-actuated flow controller controls fresh
water flow through a rinse system by means of a con-
ductivity sensor that measures the level of ions in the
rinse water. When the ion level reaches a preset min-
imum, the sensor activates a valve that shuts off the
flow of fresh water into the rinse system. When the
concentration builds to the preset maximum level, the
sensor again activates a valve that opens to resume the
flow of fresh water.
Automated controls, such as a conductivity-
actuated flow controller to control rinse water flow,
can effectively reduce rinse water waste generation.
A conductivity meter equipped with the necessary
solenoid control valve could cost approximately $700
per rinse system.
IMPROVED HOUSEKEEPING
Although the contribution of improved housekeep-
ing to overall waste minimization is difficult to quan-
tify, often simple housekeeping improvements can
provide low to no cost opportunities for reducing
waste. A plant can reduce waste by developing
inspection and maintenance schedules, controlling the
purchasing and handling of raw materials, removing
dropped parts quickly from baths, keeping filters and
other process equipment in good working condition,
and authorizing a limited number of employees to
accept and test samples from chemical suppliers.
Inspection and Maintenance
Production, storage, and waste treatment facilities
should be inspected regularly to identify leaks,
improperly functioning equipment, and other items
that may lead to waste. Frequent inspections can
identify problems before they become significant.
Items that should be inspected include piping systems,
filters, storage tanks, defective racks, air sparging
systems, automated flow controls, and even operators'
production procedures (such as drain time and rinse
methods).
Dropped, parts and tools should be removed from
process baths quickly to reduce contamination of the
bath. This can be aided by having rakes handy to
recover dropped items. Maintenance schedules should
19
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be coordinated with inspection schedules to ensure
that equipment is operating at optimal efficiency.
Chemical Purchasing and Handling
Controlling the purchasing and handling of materi-
als can reduce waste generation. Inventorying, raw
materials and ensuring that containers are completely
empty before new containers are opened reduces
stockpiling of raw materials. This practice will reduce
the potential for spills and the likelihood of mixing
poor process baths.
In addition, strict procedures should be developed
for mixing chemicals. Mixing procedures should be
designed to minimize spills; to, provide correctly
mixed booths, and to ensure that the baths are oper-
ated at the lowest possible concentration to reduce
drag-out loss. Designating a limited number of per-
sonnel to handle and mix chemicals will improve the
consistency of the solution formulations and will
decrease waste.
Sample Testing
Many suppliers provide metal finishers with a
variety of process chemicals for testing. However, if
the material is not used, it becomes waste, and unused
chemicals should not be allowed to stockpile at the
site. If possible, metal finishers should stipulate 'that
test samples will be accepted only if the supplier
agrees to take back leftover samples. The unused por-
tion of analytical samples taken from process baths
should be returned to the process bath.
Recycling and Resource Recovery
Recycling and resource recovery technologies
either directly use waste from one process as raw
material for another process or recover valuable mate-
rials from a waste stream before they are disposed.
Some spent chemical process baths and much rinse
water can be reused for other plant processes. Also,
process chemicals can be recovered from rinse wjater
and sold or returned to process baths.
Segregating waste streams is essential for most
recycling and resource recovery technologies. To
reuse a waste material for another process, recover
valuable chemicals from a waste stream, or recycle
rinse water, the waste stream must be separated from
other wastes that would prohibit recycling or reuse
opportunities. Therefore, recycling and resource
recovery technologies typically will require process
piping modifications and additional holding tanks to
provide appropriate material segregation. •
REUSING WASTE MATERIAL
The chemical properties of a waste stream must
be understood to assess the potential for reusing the
waste as a raw material. Although the chemical prop-
erties of a process bath or rinse water solution may
make it unacceptable for its original use, the waste
materials may still be valuable for other applications.
Metal finishers should therefore evaluate waste
streams for the properties that make them useful rather
than the properties that render them waste.
Rinse Water
One waste material reuse option common among
metal finishers is multiple-use rinse waters, in which
the rinse water from one process is used for the rinse
water of another. The primary cost associated with
rinse water reuse is in replumbing the rinse system.
Depending on the design of the rinse water reuse sys-
tem, storage tanks and pumps may also be needed.
After rinse solutions become too contaminated for
their original purpose, they may be useful for other
rinse processes. For example, effluent from a rinse
system following an acid cleaning bath can sometimes
be reused as influent to a rinse system following an
alkaline cleaning bath. If both rinse systems require.
the same flow rate, 50 percent less rinse water would
be used to operate them. In addition, reusing water in
this way can improve rinse efficiency by accelerating
the chemical diffusion process and reducing the vis-
cosity of the alkaline drag-out film (USEPA 1982a).
Care must be exercised to make sure that tank materi-
als and pipes as well as bath chemistries are compati-
ble with the rinse solutions.
Acid cleaning rinse water effluent can be used as
rinse water for workpieces that have gone through a
mild acid etch process. Effluent from a critical or
final rinse operation, which is usually less contami-
nated than other rinse waters, can be used as influent
for rinse operations .that do not require high rinse
20
-------
efficiencies. Another option is using the same rinse
tank to rinse parts after both acid and alkaline baths.
Metal finishers should evaluate the various rinse water
requirements for their process lines and configure
rinse systems to take advantage of rinse water reuse
opportunities that do not affect product quality.
Figure 5 illustrates rinse water reuse for an alka-
line cleaning, mild acid etch, and acid cleaning line.
If each of the three rinse tanks is operated at the same
flow rate, total water use is 67 percent less when
reused compared with no reuse.
Implementing a system to reuse rinse water efflu-
ent from one rinse system as feed water in another
rinse system costs approximately $1,000. This
includes $500 for contractor labor for 1 day and $500
for materials (including piping and a three-quarter
horsepower pump, which would be adequate for a typ-
ical rinse system). If the rinse systems are in the
same process line and operate at the same flow rate,
no storage tank capacity would be necessary.
The savings associated with reusing rinse water
are related to water and sewer fees, treatment chemi-
cals, and sludge handling. If each rinse system used
24,000 gallons of water each month, reusing rinse
water from one .rinse system could reduce water use
by 24,000 gallons each month, saving $32 per month
assuming water and sewer fees are each $0.50 per
100 cubic feet. Savings for treatment chemicals
would be approximately $120 per month if the com-
pany spends $1,000 each month to treat 200,000 gal-
lons of wastewater.
Spent Process Baths
Typically, spent acid or alkaline solutions are
dumped when contaminants exceed an acceptable
level. However, these solutions may remain suffi-
ciently acidic or alkaline to act as pH adjusters. For
example, alkaline solutions can be used to adjust the
pH in a precipitation tank. Acid solutions can be used
for pH adjustment in chromium reduction treatment.
Since spent cleaners often contain high concentrations
of metals, they should not be used for final pH adjust-
ments, however. It is important to make sure the pro-
cess solutions are compatible before they are used in
this manner. Chemical suppliers may have reclama-
tion services, some of which permit certain spent plat-
ing baths to be returned.
Workplace
Movement
i
Alkaline
Cleaning
Rinse
Mild
Acid
Etch
Rinse
Acid
Clean
Work
Product
Rinse
I
I
L_-_
Contaminated
Rinse Water to
Treatment
I I
I I
1 U
Figure 5. Multiple Reuse of Rinse Water
I
I
Fresh
Water
I Feed
21
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RECYCLING RINSE WATER
AND PROCESS BATHS
These technologies are used separately or in combina-
tion to recover chemicals from rinse water effluent.
Rinse water can be recycled in a closed loop or
open loop system. In a closed loop system, the
treated effluent is returned to the rinse system. This
system can significantly reduce water use and the
volume of water discharged to the wastewater treat-
ment plant A small amount of waste is still dis-
charged from a closed loop system. An open loop
system allows the treated effluent to be reused in the
rinse system, but the final rinse is fed by fresh water
to ensure high quality rinsing. Therefore, some
treated effluent will continue to be discharged to the
sanitary sewer. Figure 6 shows the configurations for
both a closed loop and open loop rinse water recyc-
ling system.
To improve the economic feasibility of these sys-
tems, rinse water efficiency techniques should first be
implemented. Multistage counter-current rinse sys-
tems, flow controls, and drag-out reduction techniques
should be pursued to reduce the volume of water
requiring treatment for recovery, thus reducing the
equipment capital costs.
In the past, material recovery from metal finishing
was not considered economical. However, effluent
pretreatment regulations and treatment and disposal
costs are now a significant economic factor. As a
result, metal finishers may find it economical to reuse
rinse water and to recover metals and metal salts from
spent process baths and rinse water.
Recovered metal can be reused in three ways:
(1) recovered metals (and process solutions) can be
returned to baths as makeup, (2) metals can be sold or
returned to suppliers, or (3) elemental metal can be
sold to a reclaimer or reused on site as plating nietal
anode materials. Some successful technologies to
recover metals and metal salts include:
• Evaporation \
• Reverse osmosis ;
• Ion exchange
• Electrolytic recovery (electrowinning)
• Electrodialysis. <
The savings actually achieved through metal
recovery will be site-specific. Factors that determine
whether metal recovery is economically justifiable
include the volume of waste that contains metals, the
concentration of the metals, the potential to reuse
some of the metal salts, and (he treatment and dispo-
sal costs. Many systems may not be economically
feasible for small metal finishers because the savings
may not be great enough to achieve an acceptable
payback on their investment.
Evaporation
!
Evaporation has been successfully used to recover
a variety of plating bath chemicals. This simple tech-
nology is based on the physical separation of water
from dissolved solids such as heavy metals. Water is
evaporated from the collected rinse water to allow the
chemical concentrate to be returned to the process
bath. The drag-out recovered is often returned to the
process tank in higher concentrations than in the origi-
nal process solution. Water vapor is condensed and
can be reused in the rinse system. The process is per-
formed at low temperatures under a vacuum to pre-
vent degradation of plating additives. Atmospheric
pressure evaporators are used most commonly because
of their lower capital cost. Evaporation is more eco-
nomical when used with multistage counter-current
rinse systems because the quantity of rinse water to be
processed is small. The process is energy-intensive
and becomes expensive for large volumes of water;
heat pumps and multistage counter-current rinse sys-
tems have lower operation costs. Evaporation is most
economical when the amount of water to be evapo-
rated is small or when natural atmospheric evaporation
can be used.
A variation on standard evaporation technology is
the cold vaporization process, which works by a simi-
lar evaporation separation principle except that an
increased vacuum evaporates water at temperatures of
50°F to 70°F. This type of evaporation system is less
energy intensive than electrically heated systems
because it gets the needed heat from the air around
the unit. Some equipment uses the heat generated
from the vacuum system to provide the heat needed
for evaporation.
22
-------
CLOSED LOOP SYSTEM
Workplace
Movement
r
i
i
i
I Drag-out
Process
Tank
Rinse
Rinse
I
I
I
I
I
L
Solution
Recycle
Rinse
Water
Effluent
Work
Product
Rinse
I
I
-I
Recovery
Unit
Rinse Water Recycle
I
I
I-
I
I
J
Make-up
Water
OPEN LOOP SYSTEM
Workpiece
Movement
Process
Tank
Rinse
Rinse
Work
Product
Rinse
Drag-out
Solution
Recycle
Rinse
Water
Effluent
_! A
Recovery
Unit
Make-up
water
i
Rinse
Water
Influent
Rinse Water
Recycle
Rinse Water
Effluent (to
treatment)
Figure 6. Chemical Rinse Water Recycling System
23
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Reverse Osmosis \
Reverse osmosis (RO) is a pressure-driven process
in which a semipermeable membrane permits the pass-
ago of purified water under pressure greater than the
normal osmotic pressure, but does not .allow larger
molecular weight components to pass through. These
concentrated components can be recovered and
returned to the process bath, and the treated rinse
water is then returned to the rinse system for reuse.
The most common application of-RO technologies in
metal finishing operations is in the recovery of drag-
out from acid nickel process bath rinses.. Although
the technology is designed to recover a concentrated
drag-out solution, some materials (such as boric acid)
cannot be fully recovered. Also, RO is a delicate pro-
cess that is limited by the ability of the membranes to
withstand pH extremes and long-term pressure. RO
membranes are not generally suitable for solutions
having high oxidation potential (such as chromic ac-
id). Also, the membranes will not completely reject
.many nonionized organic compounds. Therefore,
activated carbon treatment is typically required before
the rinse water solution can be returned to the rinse
system. Activated carbon can be costly, but for ;cer-
tain cases it may be the only practical approach.
Ion Exchange
Ion exchange (IX) can be used to recover drag-out
from a dilute rinse solution. The chemical solution is
passed through a series of resin beds that selectively
remove cations and anions. As the rinse water is
passed through a resin bed, the resin exchanges ions
with the inorganic compounds in the rinse water. The
metals are recovered by cleaning the resin with an
acid or alkaline solution. The metals then cari be
electrowon from the resin regeneration solution while
the IX treated water can be returned to the rinse sys-
tem for reuse. IX units can be used effectively on
dilute waste streams and are less delicate than RO
systems, but the water must be filtered to remove oil,
grease, and dirt to protect the resin. Certain qther
metals may eventually foul the resin, requiring a spe-
cial procedure to remove the foulant.
Ion exchange is commonly used to treat rinse
water from chromic acid process baths. Figure 7
shows how an IX unit can be used to recover chromic
acid and reuse rinse water. The rinse water waste
stream is filtered prior to passing through a cation
column and two anion columns. The primary cation
resin column removes heavy metals from the solution,
while the anion resin column removes the chromate
ions. The chromates are removed from the anion
resin, with sodium hydroxide, forming sodium chrom-
ate which is then regenerated as chromic acid by pass-
ing through, a secondary cation bed. The secondary
bed replaces the sodium ions with hydrogen ions. The
cation beds themselves are regenerated with hydro-
chloric acid and the spent regenerant solution is usu-
ally treated in the wastewater treatment system. It is
important to note that chloride contaminates the chro-
mium plating bath, and that treatment with silver
nitrate to precipitate the chloride is expensive.
IX equipment requires careful operation and main-
tenance. In addition, recovery of chemicals from the
resin columns generates significant volumes of regene-
rant and wash solutions, which may add to the waste-
water treatment load.
Electrolytic RecoverylElectrowinning
Electrowinning is a process used to recover the
metallic content of rinse water. It operates using a
cathode and an anode, which are placed in the' rinse
solution. As current passes between them, metallic
ions deposit on the cathode, generating a solid metal-
lic slab that can be reclaimed or used as an anode in
an electroplating tank. The electrowinning process is
capable of recovering 90 to 95 percent of the available
metals and has been successfully used to recover gold,
silver, tin, copper, zinc, solder alloy, and cadmium
(Campbell and Glenn 1982).
Several basic design features well known to the
electroplating industry are employed in electrolytic
recovery: (1) expanded cathode surface area,
(2) close spacing between cathode and anode, and
(3) recirculation of the rinse solution (USEPA 1985).
Electroplaters can design their own units: by closely
spacing parallel rows of anodes and cathodes in a
plating tank and circulating rinse solutions through the
tank. This process can also be used to recover metals
from spent process baths prior to bath treatment in the
wastewater treatment system, j
High surface area electrowinning/electrorefining is
another method of electrolytic recovery. The metal-
containing solution is pumped through a carbon fiber
cathode or conductive foam polymer, which is used as
24
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Workplace
Legend:
Primary Ion Exchange Circuit
Secondary Ion Exchange Circuit
Regeneration Circuit
Hydrochloric
To Waste
Treatment
Source: USEPA. 1985. Environmental Pollution Control Alternatives: Reducing Water Pollution Control
Costs to the Electroplating Industry.
Figure 7. Ion Exchange System for Chromic Acid Recovery
the plating surface (Mitchel 1984). To recover the
metals, the carbon fiber cathode assembly is removed
and placed in the electrorefiner, this reverses the cur-
rent and allows the metal to plate onto a stainless steel
starter sheet. These systems recover a wide variety of
metals and regenerate many types of solutions. High
surface area metal recovery is used mainly with dilute
solutions such as rinse water effluent.
Electrodialysis
Electrodialysis is used to concentrate and separate
ionic components contained in rinse water solutions,
as shown in Figure 8. A water solution is passed
through a series of alternately placed cation- and
anion-permeable membranes. These membranes are
placed parallel to the flow of water, and an anode and
cathode are placed on opposite sides of the membrane
stack. The anode and cathode create an electropoten-
tial across the-stack of membranes, causing the ions in
the rinse solution to migrate across the membranes.
The selectivity of the alternating membranes causes
both anions and cations to migrate into alternating
channels, and ion-depleted water remains in the other
channels. The concentrated solution can be returned
to the plating baths, while the treated water is recycled
through the rinse system.
EPA has sponsored demonstration projects to test
the application of electrodialysis to nickel recovery
from rinse water. One unit was tested for 9 months
without significant operating problems. This unit suc-
25
-------
Purified Stream
(to rinse tanks)
>
I >
_t_
t: >
_t_
(
t *
O
Cathode
X-
V^
& %
%^k
^J
I
I
<^
1
M+
Legend:
M+ = Cations
X--Antons
Cation—selective membrane
Anton—selective membrane
Concentrated Stream
(to plating tanks)
k >
I >
k >
k t
' f
rO
Anode
Contaminated
Rinse Water
Figure 8. Electrodialysis Flow Schematic
cessfully recovered nickel salts for reuse in plating
baths, allowing the treated rinse water to be recircu-
lated into the rinse system (USEPA 1985).
RECYCLING SOLVENTS
Many companies have converted their solvent-
based precleaning or degreasing processes to alkaline
cleaning solutions'that can be batch treated on site in
a facility's existing treatment system. Nevertheless,
solvent degreasing is still used for some cleaning
operations in the metal finishing industry.
Solvents can be recycled off site as part of a
package solvent service. Companies will rent
degreasing equipment, supply all solvents, and accept
the waste solvents for off-site recycling. These
services may be cost effective for low volume users
of solvents. High volume users of solvent cleaners
can recycle solvent waste on site using distillation
technologies. The solvent is separated from the con-
taminants by heating the solution above the solvent's
boiling point The solvent vapors are then condensed
in a condensation chamber. The contaminants remain-
ing in the heating vessel are handled as a hazardous
sludge. The- economic benefits of off-site versus dn-
site recycling have to be judged based on virgin sol-
vent purchase cost, off-site service fees, amount of
waste solvent generation, disposal cost of waste sol-
vent, disposal cost of distillation still bottom sludge,
and cost of on-site equipment. A general rule of
thumb is that on-site recovery be considered if one
drum (55 gal) or more of waste solvent are generated
per month.
26
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A recent study by Gavaskar et al. (1992) looked
at a company that generates 900 gallons of waste
methylethylketone (MEK) solvent per year. This
waste solvent could be disposed of directly at a cost
of $400 per 55-gallon drum. A 55-gallon capacity on-
site batch distillation still was used to recover the
MEK for use in a painting operation. Every 55-gallon
batch gave 35 gallons of recycled solvent and 15 to
20 gallons of still bottom sludge, on average. This
sludge was hauled away for incineration for $500
(minimum) per 55-gallon drum. Purchasing new
MEK solvent would have cost the company $10 per
gallon. Under these conditions, the batch recovery
unit, which costs approximately $30,000, has a pay-
back of around 3 years. Smaller stills of 5-gallon
capacity are also available in the $5,000 to $8,000
range. Intermediate 15-gallon stills cost between
$8,000 and $12,000.
Summary
Table 2 provides a summary of the two main
approaches to waste minimization in the metal finish-
ing industry.
References
AESF (American Electroplaters and Surface Finish-
ers). 1991. Workshop II: RCRA/SARA Regu-
latory Update. Waste Minimization Handouts,
AESF Week '91.
Campbell, Monica, and William Glenn. 1982. Profit
from Pollution Prevention—A Guide to Industrial
Waste Reduction and Recycling. Pollution Probe
Foundation, Toronto, Ontario.
Center for Hazardous Materials Research. 1987.
Hazardous Waste Minimization Manual for Small
Quantity Generators. Pittsburgh, Pennsylvania.
Couture, Stephen D. 1984. Source Reduction in the
Printed Circuit Industry. Proceedings—The
Second Annual Hazardous Materials Management
Conference, Philadelphia, Pennsylvania, June 5-7,
1984.
Cramer, Robert. 1988. Fisher Air Supply, personal
communication with Thomas P. Adkisson, PRC
Environmental Management, Inc. (April 8, 1988).
Crowe, Dave. 1988. A-l Plating, personal communi-
cation with Thomas P. Adkisson, PRC Environ-
mental Management, Inc. (April 1, 1988).
Foggia, Mike. 1987. Shipley Company, Inc., per-
sonal communication with Thomas P. Adkisson,
PRC Environmental Management, Inc.
(January 21, 1987).
Gavaskar, A. R., R. F. Olfenbuttel, J. A. Jones, and
T.C. Fox. 1992. Automated Aqueous Rotary
Washer for the Metal Finishing Industry. USEPA
(in press).
Higgins, Thomas E. 1989. Hazardous Waste Minimi-
zation Handbook. Lewis Publishers, Inc.,
Chelsea, Michigan.
Kraus, Rolf. 1988. Shipley Company, Inc., personal
communication with Thomas P. Adkisson, PRC
Environmental Management, Inc. (April 4, 1988).
Metal Finishing. 1989. Guidebook and Directory,
Vol. 87, No. 1A.
Mitchel, George D. 1984. "A Unique Method for the
Removal and Recovery of Heavy Metals from the
Rinse waters in the Metal Plating and Electronic
Interconnection Industries." Proceedings—
Massachusetts Hazardous Waste Source Reduc-
tion, Clinton, Massachusetts.
Stone, Phil. 1987. Shipley Co., Inc., personal com-
munication with Thomas P. Adkisson, PRC Envi-
ronmental Management, Inc. (Feb. 24, 1987).
USEPA. 1982a. Control and Treatment Technology
for the Metal Finishing Industry-In-Plant
Changes. EPAX 8606-0089.
USEPA. 1982b. Environmental Pollution Control
Alternatives: Sludge Handling, Dewatering, and
Disposal Alternatives for the Metal Finishing
Industry, EPA 625/5-82/018.
USEPA. 1985. Environmental Pollution Control
Alternatives: Reducing Water Pollution Control
Costs in the Electroplating Industry. September
1987. EPA 625/5-85/016.
Watson, Michael R. 1973. Pollution Control in
Metal Finishing. Noyes Data Corporation, Park
Ridge, New Jersey.
27
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Table 2. Waste Minimization Options
Source Reduction
Recycling and Resource Recovery
• Using nonchelated process chemistries
• Reducing the volume of rinse water by: ;
— Using spray rinse systems
— Creating agitation in the rinse tank
— Employing multiple use rinses for compatible
processes
— Using multiple stage counter-current rinse
systems !
— Using conductivity controls and flow timers
• Extending the life of the process baths through:
— Good housekeeping •
— Initiating electrolytic recovery or chemical treat-
ment and filtration
— Reducing drag-in . ,
— Using distilled, deionized, or reverse osmosis
water
— Properly maintaining racks
— Using purer anodes and bags
• Reducing drag-out loss by:
— Operating process baths at the lowest accept-
able chemical concentrations
— Operating process baths at higher temperatures
— Withdrawing workpiece racks at a slower rate
— Draining workpiece racks for longer periods
— Capturing drag-out on a drainage board that
drains back into the process tank \
— Adding wetting agents to process baths
— Improving workpiece positioning
— Recovering process chemicals in a drag-out tank
and replenishing the process bath with the
recovered solution
— Spraying directly over the process tank
Reusing rinse water effluent
implementing material reuse techniques
Regenerating spent process bath solutions
Recycling process bath chemicals and rinse water
solutions through use of chemical recovery technol-
ogies, including:
— Evaporation
— Reverse osmosis
— Ion exchange
— Electrolysis
— Electrowinning
— Electrodialysis
Recycling spent solvents by distillation
Separating various waste streams for recycling,
selective treatment, and batch treatment
Implementing alternative treatment systems such
as ion exchange, reverse osmosis, evaporation,
and electrolysis
28
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SECTION 4
GUIDELINES FOR USING THE WASTE
MINIMIZATION ASSESSMENT WORKSHEETS
The worksheets provided in this section are
intended to assist metal finishing facilities in systema-
tically evaluating waste generating processes and in
identifying waste minimization opportunities. These
worksheets should be used to perform the assessment
phase of the waste minimization opportunity assess-
ment procedure. The entire procedure consists of four
phases, the second of which is the assessment phase.
The full procedure is described in the EPA Waste
Minimization Opportunity Assessment Manual and
also in the EPA Facility Pollution Prevention Guide.
A comprehensive waste minimization assessment
includes planning and organization, gathering
background data and information, a feasibility study
on specific waste minimization options, and an imple-
mentation phase. For a full description of waste mini-
mization assessment procedures, refer to the EPA
manual.
Table 3 lists the worksheets that are provided in
this section. Users may wish to duplicate the work-
sheets and perform complete assessments for each
process operation. After completing the worksheets,
the assessment team should evaluate the applicable
waste minimization options and develop an implemen-
tation phase.
Table 3. List of Waste Minimization Assessment Worksheets
Number
Title
Description
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Waste Sources
Waste Minimization: Material Handling
Option Generation:
Waste Minimization:
Option Generation:
Waste Minimization:
Option Generation:
Waste Minimization:
Option Generation:
Waste Minimization:
Option Generation:
Waste Minimization:
Option Generation:
Material Handling
Material Substitution
Material Substitution
Operational Practices
Operational Practices
Drag-Out
Drag-Out
Management Practices
Management Practices
Reuse and Recovery
Reuse and Recovery
Form for listing material handling and process
operations waste
Questionnaire on handling techniques and
inspections
Options for minimizing material handling waste
Questionnaire on process operations
Options for substituting process materials
Questionnaire on operating practices
Options for modifying operating practices
Questionnaire on drag-out processes
Options for minimizing drag-out
Questionnaire on management practices
Options for implementing management practices
Questionnaire on reuse and recovery
Options for reusing and recovering process
materials
29
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Firm Waste Minimization Assossmont Prepared bv
Site , Checked by
Date Proj. No. Sheet of Page of
WORKSHEET WASTE SOURCES
1L
.
Waste Source: Material Handling
Off-spec materials
Obsolete raw materials
Spent process baths
Spills & leaks (liquids)
Spills (powders)
Empty container cleaning
Container disposal (metal)
Container disposal (paper)
Pipeline/tank drainage
Laboratory wastes
Unused samples
Trash
Used filters and media
Other
Waste Source: Process Operations
Cleaning baths
Plating baths
Etching baths
Wastewater from rinsing
Strippers
Degreasing solvents
Cleaning rags
Lube oils
Other
Significance at Plant
Low
Medium
.High
!
30
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Firm . Waste Minimization Assessment
Site
Date Proj. No.
WORKSHEET WASTE MINIMIZATION:
2A Material Handling
A. GENERAL HANDLING TECHNIQUES
Prepared by
Checked by
Sheet of Page
of
Are off -specification material wastes generated because the material has exceeded its shelf life? D Yes
How often is an inventory performed to identify an accumulation of materials
Does the company use a first-in first-out material use policy to prevent mate
ting in storage? /•
?
•ials from deteriora-
D Yes
Does the company minimize inventory to prevent material degradation due to prolonged storage? D Yes
Does the plant accept samples from chemical suppliers?
Do unused samples become waste?
Are samples tested on a bench-scale basis to minimize waste generation?
Has a person been designated for approving the acceptance of samples?
Are suppliers required to take back unused samples they provide?
Are process bath solutions mixed by designated and trained personnel?
D Yes
D Yes
DYes
DYes
DYes
D Yes
Are inventory controls used to assure that chemicals in a container are completely used prior to
opening a new container? D Yes
Are empty containers returned to the supplier?
DYes
Are empty containers empty according to 40 CFR 261.7 so they can be handled as a nonhazard- D Yes
ous solid waste?
Are container rinse solutions used for process bath mixing?
DYes
Does the plant generate waste due to spills during material handling or storage? D Yes
If yes, describe the frequency of these spills.
Are personnel trained to ensure proper handling and storage of materials?
DYes
Is spill containment provided to minimize the amount of cleanup materials used to contain and Q Yes
clean up spills?
Describe spill containment used in material storage areas.
DNo
DNo
DNo
DNo
DNo
QNo
DNo
DNo
DNo
DNo
DNo
DNo
DNo
DNo
DNo
DNo
31
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Firm.
Site
Date
Waste Minimization Assessment
Proj. No.
Prepared by
Checked by
Sheet of Page _
of
WORKSHEET
2B
WASTE! MINIMIZATION:
Material Handling
B. DRUMS, CONTAINERS, AND PACKAGES
Are drums, packages, and containers inspected for damage before being accepted?
Are employees trained in ways to safely handle the types of drums & packages received?
Are stored items protected from damage, contamination, or exposure to rain, snow, sun & heat?
Does the layout of the facility result in heavy traffic through the raw material storage area?
(Heavy traffic Increases the potential for contaminating raw materials with dirt or dust and for
causing spilled materials to become dispersed throughout the facility.)
Can traffic through the storage area be reduced to prevent accidents?
Are employees properly trained in handling of spilled raw materials?
Describe handling procedures for damaged items: '
D Yes D No
D Yes D No
D Yes D No
D Yes D No
D Yes D No
D Yes D No
What measures are employed to prevent the spillage of liquids being dispensed?
When a spill of liquid occurs in the facility, what cleanup methods are employed (e.g., wet or dry)? Also discuss
the way in which the resulting wastes are handled:
Would different cleaning methods allow for direct reuse or recycling of the waste? (explain):
Do you try to order smaller containers of infrequently used materials to avoid disposing of large. D Yes Q No
quantities of unused obsolete materials?
I
Have you tried to order larger containers of frequently used materials to reduce the number of [] Yes D No
small containers that must be cleaned and disposed of?
Are all empty bags, packages, and containers that contained hazardous materials segregated Q Yes D No
from those that contain non-hazardous wastes?
Describe the method currently used to dispose of this waste:
32
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Firm.
Site
Date
Waste Minimization Assessment
Proj. No.
Prepared by
Checked by
Sheet of Page.
of
WORKSHEET
2C
WASTE MINIMIZATION:
Material Handling
C. INSPECTIONS
Does the company have a formal inspection program? QYes Q No
How often are inspections of the chemical storage area, process areas, and waste treatment
.areas conducted?
Are malfunctions in equipment or leaks in storage vessels and piping corrected immediately? Q Yes Q No
Are identified malfunctions followed up to ensure that they are corrected? Q Yes D No
Are inspections logged and are logs maintained in permanent records? Q Yes Q No
33
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Firm Waste Minimi7atinn As?
Site
Date Proj. No.
essment F
C
S
'repared bv
Jhecked by
>heet of Page of
WORKSHEET OPTION GENERATION:
3 Material Handling
Meeting Format (e.q.. brainstorming, nominal group technique)
Meeting Coordinator
i
Meettnq Participants !
Suggested Waste Minimization Options
A. General Handling Techniques
Quality Control Check
Test Age-Dated Material (if expired) for Effectiveness
Return Obsolete Material to Supplier
Minimize Inventory
Computerize Inventory
Formal Training
B. Drums, Containers, and Packages |
Raw Material Inspection i
Proper Storage/Handling
Reduced Traffic !
Spilled Material Reuse !
Cleanup Methods to Promote Recycling :
Appropriate Purchase Sizes ;
Waste Segregation
C. Inspections ;
Formal Inspections
Maintenance Inspections \
Inspection Logs/Follow-Up '
'
Currently
Done Y/N?
Rationale/Remarks on Option
34
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Firm
Site
Date
Waste Minimization Assessment
Proj. No.
Prepare'd by
Checked by
Sheet of Page
of
WORKSHEET
WASTE MINIMIZATION:
Material Substitution
Do any of the process solutions used contain hazardous materials (i.e., cyanide, chromium VI, Q Yes B No
chlorinated solvents, etc.)?
If yes, has material substitution been tried? QYes QNo
Discuss the results: _ -
Is deionized or reverse osmosis water available?
Is it used for bath makeup water?
Is it used for rinse water?
If used, where, and explanation:
D Yes D No
D Yes D No
D Yes D No
Do any of the process solutions contain chelating compounds?
If yes, has material substitution been tried?
Discuss the results:
D Yes D No
D Yes D No
Does the company generate spent process bath wastes that are not treated on site because of Q Yes D No
concerns about upsetting the treatment process?
Has the company attempted to replace all process bath chemicals, which are handled as n Yes D No
hazardous waste when spent, with chemicals that can either be recycled or treated on site?
35
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Firm Waste Minimization Assessment Prepared by
Site
Date Proi. No. ;
Checked by
Sheet of Paqe of •
WORKSHEET OPTION GENERATION:
5 Material Substitution
Meetinq Format (e.a, brainstormina, nominal aroup technique)
Meetinq Coordinator
Meelinq Participants
Suggested Waste Minimization Options
Substitution/Reformulation Options
Cyanide Substitution '
Solvent Substitution
Chromium VI Substitution
Other Raw Material Substitution !
Deionized or Reverse Osmosis Water
Chelating Compound Replacement
Cadmium Substitution i
' (
i
i
i
• i
i
i
Currently
Done Y/N?
Rationale/Remarks on Option
36
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Firm
Site
Date
Waste Minimization Assessment
Proj. No.
Prepared by .
Checked by
Sheet of; Page.
of
WORKSHEET
WASTE MINIMIZATION:
Operational Practices
Are process baths mixed by designated and trained personnel? P Yes D No
Are process baths filtered to extend usefulness? Q Yes D No
Are process baths treated to extend usefulness (i.e., precipitation, dummying)? p Yes D No
Are anodes bagged to reduce contamination? p Yes P No
Are pure anodes used? P Yes D No
Are process bath chemistries monitored and maintained? p Yes D No
Are operators trained/aware of proper operating procedures? Q Yes D No
Are rinse systems only in operation when needed? p Yes D No
Are rinse water flows kept at minimum flow rates? p Yes D No
Are rinsing enhancements used (i.e., agitation, spray rinse, counter-current rinse, dead rinse, P Yes D No
flow controllers)?
37
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Firm Waste Minimization As?
Site
Date Proi. No. ;
jessment F
C
S
'repared by
Checked bv
Sheet of Paae of
WORKSHEET OPTION GENERATION:
7 Operational Practices
Meeting Format (e.g., brainstorming, nominal group tephnique)
Meeting Coordinator ;
Meelina Participants
Suggested Waste Minimization Options
Designated and Trained Personnel Mix Baths .
Process Bath Filtration
Process Bath Treatment
Dummying
Precipitation
Bag Anodes
Use Pure Anodes
Regular Bath Analysis/Maintenance
Regular Operator Training
Rinse Water Flow Restrictions
Rinse Water Automatic Controllers
Multiple Rinse Tanks
Counter-Current Rinse Tanks j
Reduced Rinse Water Flow Rates i
Workpiece Rack Agitation
Turbulence Agitation '•
t
i
f
Currently
Done Y/N?
Rationale/Remarks on Option
38
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Firm.
Site
Date
Waste Minimization Assessment
Proj. No..
Prepared by '
Checked by
Sheet of Page
of
WORKSHEET
8
WASTE MINIMIZATION:
Drag-Out
Has an optimal removal rate and drain time for workpiece racks been determined for each Q Yes O No
process bath?
Are personnel trained to consistently follow proper workpiece rack removal rates and drain Q Yes Q No
times?
Are personnel retrained periodically to assure that these procedures are followed? , Q Yes Q No
Can any of the chemical process baths be operated at a higher temperature without adversely Q Yes Q No
affecting production quality?
Are process baths operated at the lower end of the manufacturers' suggested range of operating Q Yes' Q No
concentrations? ...
Are fresh process bath solutions operated at a lower concentration than replenished process Q Yes D No
bath solutions? , , .
Are spray rinses used above heated baths to rinse drag-out solutions back into the process Q Yes D No
tank?
Is there space between process bath tanks and their associated rinse tanks that allows process Q Yes Q No
chemicals to drip onto the floor?
Do process baths that operate at elevated temperatures use drag-out tanks as the initial rinse Q Yes Q No
following the bath?
If yes, is the drag-out tank solution added back to the process tank? [] Yes Q No
Has the company studied the possibility of using the drag-out solution for process bath QYes QNo
replenishing?
39
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Firm Waste Minimization As=
Site !
Dale Proj. No. :
sessment F
C
£
'repared by
Checked by
>heet of Page of
WORKSHEET OPTION GENERATION:
9 Drag-Out
,
!
Meetinq Format (e.q.. brainslorminq, nominal qroup technique)
Meetinq Coordinator i
Meetinq Participants :
I
Suggested Waste Minimization Options
Slower Workpiece Removal Rates j
Longer Workpiece Drain Times ;
Elevated Process Bath Temperatures I
Reduced Process Bath Concentrations \
Spray Rinse Above Process Tank
Air Knife Above Process Tank ;
Drain Boards :
Drag-Out Tanks
Drag-Out Solution Reuse :
Rack Design, Workpiece Positioning
1
1
\
•
\
[
i
!
1
! .
i
i
i
i
Currently
Done Y/N?
Rationale/Remarks on Option
40
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Firm ; Waste Minimization Assessment
Site ;
Date Proi. No.
WORKSHEET WASTE MINIMIZATION:
"| 0 Management Practices
Are plant and/or process material balances routinely performed?
Are they performed for each material of concern (e.g., solvent) separately?
Are records kept of individual wastes with their sources of origin and eventua
(This can aid in pinpointing large waste streams and focus reuse efforts.)
Are the operators provided with detailed operating manuals or instruction sets
Are all operator job functions well defined?
Are regularly scheduled training programs offered to operators?
Are there employee incentive programs related to waste minimization?
Does the facility have an established waste minimization program in place?
If yes, is a specific person assigned to oversee the success of the program?
Discuss qoals of the proqram and results:
Has a waste minimization assessment been performed at the facility in the pa
If ves, discuss: ......
Prepared by
Checked bv
Sheet of Page of
D Yes Q No
DYes DNo
disposal? D Yes D No
? DYes DNo
D Yes D No
DYes DNo
DYes DNo
D Yes Q No
DYes DNo
st? D Yes D No
41
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Firm Waste Minimization As?
Site
Date Proj. No.
>essment f
C
£
'repared bv
Checked by
Jheet of Page of
WORKSHEET OPTION GENERATION:
"| "j Management Practices
I
Meeting Format (e.g., brainstorming, nominal group technique)
Meetinq Coordinator !
Meeting Participants i
Suggested Waste Minimization Options
Perform Material Balances
Keep Records of Waste Sources & Disposition
Waste/Materials Documentation
Provide Operating Manuals/Instructions
Employee Training ;
Increased Supervision j
Provide Employee Incentives :
Increase Plant Sanitation
Establish Waste Minimization Policy
Set Goals for Source Reduction
Set Goals for Recycling
Conduct Waste Minimization Assessments at Least Annually
Currently
Done Y/N?
Rationale/Remarks on Option
1
,
42
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Firm Waste Minimization Assessment
Site
Date Proi. No.
WORKSHEET WASTE MINIMIZATION:
"| 2 Reuse and Recovery
A. SEGREGATION
Prepared by
Checked bv
Sheet of Page of •
Segregation of wastes reduces the amount of unknown material in waste and improves
prospects for reuse & recovery.
Are spent processing baths segregated from wastewater streams?
.. Are different solvent wastes from equipment cleanup segregated?
°Yes °No
°Yes °No
Are aqueous wastes from equiprnent cleanup segregated from solvent wastes? ^ Yes ^ No
Are waste streams not needing treatment sent to treatment?
Are cyanide waste streams segregated?
Are chromium waste streams segregated?
B. CONSOLIDATION/REUSE/RECOVERY
Do you return waste solutions to the manufacturer for recycling?
Do you recycle the materials on site?
Are rinse water streams recycled?
Are the metals in spent process baths reclaimed?
Are spent process baths used for other beneficial purposes?
^ Yes ^ No
^ Yes ^ No
°Yes DNo
L-l Yes ^ No
D Yes D No
a Yes a No
D Yes ° No
Byes DNo
Have you contacted any other platers in your area to see if they want your solutions for ^ Yes ^ No
recycling?
Have you contacted waste exchange services or commercial brokerage firms regarding wastes? ^ Yes ^ No
Are many different solvents used for cleaning?
°Yes °No
If too many small-volume solvent waste streams are generated to justify on-site distillation, can ^ Yes ^ No
the solvent used for parts and equipment cleaning be standardized?
Is spent cleaning solvent reused as thinner or initial wash?
D Yes Q No
Has on-site distillation of the spent solvent ever been attempted? (On-site recovery of solvents ^ Yes ^ No
by distillation is economically feasible for as little as 50 gallons of solvent waste per month.)
If yes, is distillation still being performed?
If no, explain:
D Yes G No
Discuss other wastes that you are currently recycling and by which means:
i
.;
43
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Firm.
Site
Date
Waste Minimization Assessment
Proj. No..
Prepared by _
Checked by _
Sheet of
.Page.
of
WORKSHEET
13
OPTION GENERATION:
Reuse and Recovery
Meeting Format (e.g., brainstorming, nominal group technique).
i
Meeting Coordinator
Meeting Participants i
Suggested Waste Minimization Options'
Currently
, Done Y/N?
Rationale/Remarks on Option
Material Recycling
Reverse Osmosis
Ion Exchange
Electrowinning
Evaporation
Combinations
Solvent Recovery On-Site
Solvent Recovery Off-Site
Waste Exchanges
Others
Rinse Water Recycling
Reverse Osmosis
Ion Exchange
Electrolytic Recovery/Electrowinning
Electrodialysis
Evaporation
Combinations
Others
44
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Appendix A
METAL FINISHING FACILITY ASSESSMENTS:
CASE STUDIES OF PLANTS
In 1988, with funding from USEPA, the California
Department of Health Services commissioned a waste
minimization study, Waste Assessment Study: Metal
Finishing Industry, that included assessments of three
metal finishing facilities. The objectives of the study
were to:
• obtain information on waste management prac-
tices in the metal finishing industry
• identify waste reduction options
• present information on the cost associated with
implementing these options.
For a waste reduction assessment to be successful,
it must be comprehensive. Although addressing vari-
ous waste generation problems one at a time or in a
piecemeal manner may provide some degree of waste
reduction, this method overlooks the main focus of a
successful assessment. The main focus is to view the
metal finishing plant as a single system and to identify
the relationships between material usage, production
processes, and waste generation. This comprehensive
approach can lead to greater reductions in waste and
increases in the economic efficiency of the plant.
A comprehensive study of a company's waste
problem requires more than a characterization of the
various waste streams. The solution for reducing a
particular waste stream often involves modifying
material input or production procedures. Therefore,
an assessment must examine raw material usage, pro-
duction processes and schedules, and waste handling
methods together as one system.
Results of waste reduction assessments provide
valuable information about the potential for incorpo-
rating waste reduction technologies into metal finish-
ing operations. This Appendix presents summaries of
the results of the assessments performed by California
DHS at three metal finishers. The summaries pre-
sented are largely unedited and should not be taken as
recommendations of the USEPA; they are provided as
examples only. In addition, the California focus
included more than waste reduction alternatives; it
also addressed treatment alternatives that would lead
to sludge and waste water volume reduction. These
recommendations are also included in the assessment
summaries.
The original assessments may be obtained from:
Mr. Benjamin Fries
California Department of Toxic Substances Control
714/744 P Street
Sacramento, CA 94234-7320
(916) 322-8701.
45
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PLANT A WASTE MINIMIZATION ASSESSMENT
Plant A operates as a job shop metal finishing
plant. The plant operates manual and automated pro-
cess lines 8 hours a day, 5 days a week, with a pro-
duction staff of 10. Manufacturing operations include
plating, anodizing, stripping, etching, cleaning, topi-
ing, and other finishing processes. ,
i
Process Description :
Production processes that generate hazardous waste
include plating, anodizing, etching, stripping, and
rinsing. Wastes result from process bath and cleaning
bath dumps, degreasing operations, rinsing operations,
industrial wastewater treatment, and occasional spill
cleanup.
PROCESS BATHS
Plant A offers a full line of metal finishing services
and, therefore, operates a wide variety of process
baths. Fresh baths are mixed within the chemical
manufacturer's suggested concentration range using
tap water. Baths are heated when specified. Process
bath operating concentrations are checked when fresh
baths are mixed using in-house testing methods such
as the Hull cell or Kocour sets. Bath quality is evalu-
ated through visual inspection of the workpieces.
When it becomes too contaminated, the bath is taken
off line and a fresh bath is made up. Continuous fil-
tration is necessary for process baths that tend [to
accumulate solids.
The process area for the manual line is bermed'to
separate the area into three segregated sections for
nickel, chromium, and other chemicals. Therefore,
drag-out that falls onto the floor from the process
baths flows into one of three sumps used to segregate
these wastes. Wastes are then pumped to the appro-
priate holding tank for wastewater treatment. Plant A
does not use drag-out tanks, drip bars, or draina'ge
boards to control drag-out loss. ;
In the past, Plant A containerized spent baths for
off-site disposal. However, the plant recently pur-
chased a vacuum evaporation treatment unit to treat
all spent baths with the exception of nitric acid, which
is containerized for off-site disposal.
RINSE SYSTEMS
Plant A operates 18 rinse systems. Most of these
are single-stage systems associated with the automated
line. Four double-stage counter-current rinse systems
are associated with the manually operated process
lines. Plant A also operates two heated static rinses
that are used as a final rinse for the workpieces before
drying. Another static rinse tank segregates the cya-
nide waste stream.
Each tank of the four double-stage counter-current
rinse systems is used for numerous rinsing operations,
and contaminants from a variety of process baths enter
each rinse system. Because the rinse tanks are in the
center of the manual process line area, workpiece
racks are carried across the aisles from the process
baths to the rinse tanks. This allows drag-out to drip
to the floor underneath the aisle grates.
The hoist used for the automated line is equipped
with a spray rinse for rinsing workpieces above the
process tanks. Air spargers are used in the four
double-stage counter-current tanks to create turbulence
and .improve rinse efficiency.
WASTEWATER TREATMENT
Plant A's industrial wastewater treatment facility
treats all wastewater before it is discharged to the
publicly owned treatment works (POTW). The treat-
ment facility removes metal contaminants to meet the
discharge requirements set by the POTW. Effluent is
tested daily for zinc, copper, nickel, chromium, and
cadmium. Historically, the plant has exceeded its
discharge requirements two to three times per year.
The primary source of wastewater treated at the
plant is for rinsing. These wastes are segregated
based on their chemical composition and pumped into
one of three holding tanks. One tank receives chrom-
ium waste; another receives electroless nickel waste;
and the third receives general waste from all other
processes. Some spent process baths and runoff from
the process area floor are also discharged into one of
the three holding tanks for treatment.
46
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Waste Reduction Recommendations
The California audit team identified several oppor-
tunities for waste reduction at Plant A. These
included process baths, rinse systems, material recy-
cling, and wastewater treatment. The following is a
summary of the recommendations of the audit team.
PROCESS BATHS
The waste reduction opportunities for process baths
at Plant A include material substitution, bath operation
and maintenance improvements, drag-out reduction,
and drag-out recovery.
Process Bath Material Substitution
The audit team recommended that Plant A replace
its cyanide process bath chemistries with chemistries
that do not contain cyanide. (Editor note: Replace-
ments for cyanide bath chemistries should be investi-
gated for their ability to fit the needs of the company.)
Plant A could eliminate the need for treating rinse
waters with sodium hypochlorite if it used chemistries
that do not contain cyanide. This could reduce waste
treatment costs,
Process Bath Operation and Maintenance
According to the audit team, Plant A may be able
to extend the life of some of its baths through
improved maintenance. Several techniques are avail-
able, including the use of deionized water for bath
makeup, treatment of plating baths, and increased
monitoring of process baths.
The audit team recommended that Plant A mix
fresh baths and replenish process baths with deionized
water instead of tap water. The condensate water
from the vacuum-evaporation treatment unit could be
used for this purpose. However, Plant A should test
the water to ensure that it is deionized quality water.
This may require the purchase of a holding tank that
costs between $400 and $600.
The life of process baths can be extended by regen-
erating them with fresh chemicals. Instead of dump-
ing the entire bath once its effectiveness declines, the
bath can be partially dumped and fresh chemicals and
water added. As the life of the bath increases, the
concentration of chemicals in the bath-replenishing
solution is increased. When the cost of adding chemi-
cals becomes greater than that of dumping the entire
bath and mixing a new solution, the bath should be
dumped.
The plant can also extend the life of its plating
baths by periodically treating them to remove metal
contaminants. "Dummying" can be used to remove
copper from zinc and nickel plating baths, using a
"trickle current" with a density of 1 to 2 amperes per
square foot to plate the copper contaminants out of the
bath. The process can be performed over a weekend
when the plant is not operating. Other metal contam-
inants, such as lead and cadmium, can be removed
through chemical treatment using zinc sulfide. The
lead or cadmium will precipitate out and can be
removed by filtration.
Extending process bath life requires strict bath
analysis schedules. Frequently used baths should be
analyzed weekly or biweekly to monitor bath concen-
tration and contamination. These analyses can be
accomplished in-house by using basic chemical titra-
tion tests or with outside laboratory analysis services.
Drag-out Loss Reduction
Numerous opportunities exist for reducing drag-out
loss at Plant A. Plant A should develop operation
procedures for the manually operated tanks to desig^
nate optimal removal rates and drainage time—the
slower the withdrawal of workpiece racks, the thinner
the film on the workpiece surface. Also, drip bars for
workpiece racks above process baths would allow
increased drainage before rinsing begins. The auto-
mated hoist line should be set at an optimal workpiece
rack removal rate, and timers should be used to ensure
that workpiece racks are drained long enough.
Drag-out loss can also be reduced by operating the
baths at lower chemical concentrations. Plant A
should rearrange its process tanks and rinse systems
so that plant personnel do not have to carry work-
pieces across aisles, allowing chemicals to drip to the
floor. A 150-gallon rinse tank costs approximately
$400, but the company itself could build these tanks
for significantly less.
47
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Drag-out Recovery \
Plant A should replenish heated process tanks with
drag-out solutions recovered in static drag-out tanks.
Deionized water should be used for the static drag-but
tank to minimize the addition of contaminants into the
process bath. The plant should identify heated baths
that can be replenished with a drag-out solution and
determine how to rearrange process tanks to provide
room for new drag-out tanks (which cost approxi-
mately $400 for a 150-gallon tank.) Savings from
using a drag-out tank include decreases in process and
treatment chemical costs, water purchase costs, and
sludge handling costs.
RINSE SYSTEMS
Rinse water reduction can improve the plant's rins-
ing efficiency and reduce the volume of wastewater
requiring treatment. Rinse system options include
waste stream segregation, multistage rinse systems,
rinse water flow reduction using flow restrictors, tim-
ers, or pH/conductivity meters combined with auto-
matic flow adjusters, and closed loop ion exchange
rinse water recycling. i
Rinse Water Efficiency
Plant A may be able to reduce water usage by add-
ing rinse tanks to its manual process line. Plant A
may be able to control the flow of water through j its
rinse systems by using automated flow controls. The
rinse system could be equipped with pH/conductivjity
meters (which cost approximately $700) that will
automatically turn the rinse water flow on and off as
needed. This can eliminate the problem of having the
water running even when the rinse process is not in
use. :
Air spargers could be installed on all the lajge
rinse tanks for approximately $50 per tank. However,
this assumes the company has an existing source!of
compressed air.
i
The savings associated with improved rinse effi-
ciency are difficult to quantify. A 50 percent reduc-
tion in water usage at Plant A would save the com-
pany approximately $150 each month in water and
sewer fees (assuming water and sewer fees are $1.15
for each 748 gallons of water purchased as indicated
on past water bills for the company). In addition,
reducing water use will also reduce treatment chemi-
cal and waste.handling costs.
Rinse Water Reuse
Plant A should also consider reusing the rinse
water following an acid cleaning bath as rinse water
following an alkaline bath. (Editor note: Provided
the streams'are otherwise compatible.)
For the large static rinse tanks, the schedules for
dumping acidic and alkaline rinse solutions could be
coordinated so that an acid rinse solution is dumped
into the alkaline process bath rinse system. This prac-
tice could cut wastewater usage by 50 percent for
these tanks.
Flow-through rinse systems following acidic pro-
cess lines can be plumbed in series with rinse systems
following acidic process baths to feed the effluent
from the acidic rinse system into the alkaline rinse
system. The rinse systems chosen for plumbing in
series would need to operate at a similar flow rate and
at the same time.
If the rinse systems in the automated process lines
are used as static rinses, Plant A would only have to
pump the spent rinse water from one tank to another
where it can be reused, using existing portable pumps.
For flow-through systems, however, additional plumb-
ing and holding tanks would be required. Such a
system, including a water pump, could cost approxi-
mately $500.
Material Recycling
To recover treatment chemicals from rinse water,
Plant A should completely segregate the rinse water
effluent from other rinse water or process chemicals.
An ion exchange system could be used to recover
chromic acid to replenish the plating bath. The cation
column could then be regenerated with hydrochloric
acid. The treated rinse water could be recycled back
to the rinse system. Plant A could reduce chemical
purchase costs, water usage costs, and waste treatment
and disposal costs by recovering chromium solutions
and recycling water.
An ion exchange unit designed to treat up to
3,000 gallons designed to treat up to 3,000 gallons of
water each day would cost approximately $80,000.
48
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Holding tanks, piping, and pumps for regenerating the
resin -and recovering chormate solutions would cost
several thousand dollars more.
Plant A should consider chemical recovery technol-
ogies for other process lines. Treatment technologies
such as ion exchange can also be used to recover rinse
water. Plant A should also consider using the treated
effluent from the vacuum-evaporation unit, which is
considered deionized quality water, for reuse in the
rinse systems or for process bath mixing and
replenishing.
WASTEWATER TREATMENT
Sludge volume reduction can be achieved by using
alternative treatment processes or by modifying the
existing wastewater treatment system.
Wastewater Segregation
Plant A generates several rinse water wastes that
should not require metal removal. Therefore, these
rinse solutions should be segregated from the other
rinse water wastes so that they do not go through the
metal precipitation treatment process. .These wastes
could be blended into the treated effluent prior to final
pH adjustment and discharge to the POTW. However,
the rinse water should be analyzed, for metals and
checked for organics that are listed in the water pollu-
tion control regulations if the chemical suppliers will
not confirm that regulated compounds do not exist in
their process baths.
Segregation of these rinse solutions will require
additional rinse systems, however. Currently, the
rinse systems following dye processes are also used
for other processes that typically require full treat-
ment. Segregation of these waste streams could
reduce treatment chemical purchase costs and sludge
handling costs.
Plant A should also segregate all chromium wastes
including the rinse water. The chromium processes
used in the manual process lines appear to use the
same rinse tanks as other processes such as the nickel
acetate, anodize, and dye baths. This increases the
volume of rinse water treated for chromium reduction.
Therefore, reducing the volume of wastewater requir-
ing treatment will reduce sludge volume by reducing
treatment chemicals.
Metal Recovery
Plant A should consider electrolytic metal recovery
from spent process baths and concentrated rinse solu-
tions prior to treatment. By removing metals from
these waste streams, the plant can minimize the gener-
ation of metal hydroxide during wastewater treatment
and, therefore, reduce sludge volume. Metals could
also be recovered from spent baths prior to evapo-
ration treatment. ,
The type of electrolytic recovery equipment neces-
sary to recover metals depends, on the concentration of
these metals in the waste stream. Dilute rinse solu-
tions require a-high surface area electrolytic metal
recovery unit. Concentrated waste streams, however,
can be batch treated in an existing plating tank. The
cost of implementing batch treatment and electrolytic
metal recovery processes would include construction
of metal plate cathodes and inert anodes.
Plant A could batch treat spent process baths for
metal recovery prior to chemical treatment. This
would reduce the contaminant metal load on the treat-
ment system and reduce the,volume of sludge gene-
rated. Savings would include reduced treatment
chemical purchase and sludge disposal costs. In addi-
tion, the plant could generate revenues by reselling the
recovered metals.
Sludge Dewatering
Plant A can reduce sludge volume by further dewa-
tering its sludge. Currently, the company uses a filter
press to increase sludge solids to 35 percent. A
sludge dryer could increase solids content up to 90 to
95 percent, representing a 60 to 65 percent reduction
in sludge volume. Since the company generates
approximately 50 55-gallon drums of sludge annually,
(according to 1987 data) the use of a dryer could
reduce that amount to approximately 17 drums. Sev-
eral types of sludge drying units are available. A unit
designed to handle approximately 20 gallons of sludge
per day Jhat uses an electrical heating unit costs
approximately $10,000. These types of units are
energy intensive and can cost approximately $6.00 per
day to operate. Therefore, annual operating costs
would be $1,500. Other units are available that use
steam as the heat source. A dryer of this type,
designed to handle approximately 15 gallons of sludge
per day, costs $9,000. However, a steam source
49
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would also be required. A steam generator would
cost approximately $4,000. These units are less
energy intensive than units using electrical heating.
Electrical costs to operate a steam dryer are approxi-
mately $0.50 per day, not including the cost of gene-
rating the steam.
i
Savings associated with using a sludge dryer
include reduced sludge disposal costs. If Plant A pays
$16,000 per year to dispose of industrial waste treat-
ment sludge, and reduces the volume by 60 percent, it
could save $9,600 annually. Annual operating costs
would be $1,500 if a unit that operated on electricity
was used. Because such a unit costs $10,000, pay-
back would be 15 months. Actual payback will take
longer if labor and maintenance costs are included. 1
Alternative Treatment Processes
i
Plant A currently treats chromium waste with
sodium metabisulfite to reduce chromium. Tjhis
requires the pH of the waste stream to be between fe.O
and 2.5. The company should consider reductions
with ferrous sulfate, which does not require pH adjust-
ments down to 2.0. Although the resultant ferric ipns
will precipitate out and contribute to sludge volume.
often the contribution is not as great as the pH adjust-
ment chemicals used for bisulfite reduction. Testing
the ferrous sulfate treatment process will, however,
require investments in time and treatment chemicals.
The savings associated with alternative chromium
waste treatment will include reduced treatment chemi-
cal purchases.
Plant A should evaluate its existing chromium
treatment process to determine if alternative treatment
chemicals could be used to reduce sludge volume.
The plant should also consider electrolytic cyanide
treatment to supplement its current sodium hypochlo-
rite destruction. The advantage of this treatment over
alkaline/chlorination treatment is that no sludge is
generated, but this process is energy intensive and is
only possible for very small batch treatment (i.e., bath
dumps).
Electrolytic treatment of concentrated cyanide
solutions can be performed in existing electroplating
tanks. The cost of implementing electrolytic cyanide
treatment would include construction of metal plate
cathodes and inert anodes. Savings would include
reduced treatment chemical purchases because the
sodium hypochlorite treatment step is eliminated.
50
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PLANT B WASTE MINIMIZATION ASSESSMENT
Plant B operates a job shop metal finishing plant.
The company's process lines are all manually oper-
ated. The plant operates 24 hours a day, 5 days a
week, with a staff of 19 platers, four assemblers, five
QA/QC personnel, six compliance personnel, and one
lab operator. Manufacturing operations include plat-
ing, anodizing, stripping, etching, cleaning, and other
finishing processes. In the following discussion, the
recommendations of the California audit team are
summarized.
Process Description
Production processes that generate hazardous waste
include plating, anodizing, etching, stripping, and rin-
sing activities. Waste includes spent baths and clean-
ing baths, contaminated rinse water, industrial waste-
water treatment sludge, empty containers, and filter
material.
PROCESS BATHS
Plant B offers a full line of metal finishing services
and, therefore, operates a wide variety of process
baths. Since all process baths are manually operated,
workpiece racks and process baths are relatively
small. Fresh baths are based on the chemical manu-
facturers' suggested operating parameters and on the
plant's operating experience, using deionized - water.
Process baths are heated when specified by the
manufacturer.
Bath concentrations are tested weekly in an in-
house laboratory. Process baths are replenished with
deionized water to prevent the buildup of natural con-
taminants, which are removed through continuous
filtration.
If a chemical process bath no longer provides the
necessary plating quality, it is replaced. Cleaning
baths are usually dumped every 1 to 6 months. Plat-
ing baths will last for several years. Chromate con-
version baths, however, are often replaced on a job-
by-job basis.
Spent process baths are batch treated at Plant B.
The spent baths are analyzed in house to identify the
necessary treatment procedures. Specific guidelines
are used to treat each spent bath following analysis.
At. times the treatment process (such as pH adjust-
ment) begins during the analysis stage, which enables
the plant to operate more efficiently. The treatment
process is recorded, treated effluent is added to the
wastewater treatment system influent, and the sludge
is pumped into the sludge dewatering unit.
None of the spent baths generated at Plant B are
containerized for off-site disposal. Highly chelated
cleaners, which were containerized for off-site dispo-
sal, have been replaced with nonchelated products. In
addition, the cyanide-containing process baths, with
the exception of the copper strike bath, are being
replaced with noncyanide baths.
RINSE SYSTEMS
Plant B operates 22 rinse systems, most of which
are multistage, counter-current, rinse systems. There
are 17 three-stage rinse systems and one two-stage
rinse system. The flow rate varies with the work load
and usually ranges from 1 to 3 gallons per minute
Four static rinse tanks are used at Plant B. Two
are heated and used for processes requiring a fast
drying time. The static rinse water is normally
replaced weekly or biweekly and batch treated.
Spray rinse equipment is used on the zinc and cad-
mium chromate rinse tanks to remove residual con-
taminants from the seams on sheet metal parts. This
rinse system is positioned above the counter-current
tank and is used after initially rinsing metal parts by
immersion.
Flow restrictors have been installed on the rinse
water influent lines in each rinse tank. Also, the main
water line for all rinse system lines is equipped with a
flow restrictor to limit total flow to 15 gpm. Because
the plant has 18 flow-through rinse systems, each
operating at 1 to 3 gpm, operators must tarn off
unused rinse systems so that those in use will operate
properly.
51
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The plant also uses rinse systems for multiple pur-
poses that enhance rinse efficiency. A closed loop ion
exchange system is used with four of the multistage
counter-current rinse systems to recover rinse water.
Plant B plans to convert the copper strike rinse systpm
to a closed loop ion exchange recovery system. :
These water conservation techniques have signifi-
cantly reduced water usage at the plant. Rinse water
use has been reduced from approximately 20,000 gal-
lons per day (gpd) to less than 10,000 gpd.
WASTEWATER TREATMENT '
Plant B's industrial waste treatment facility treats
all wastewater before it is discharged to the local pub-
licly owned treatment works (POTW). The treatment
system includes chromium reduction, cyanide destruc-
tion, metals precipitation, and pH adjustment. j
i
i
Wastewater influent from the rinse systems and
batch treatment process is collected in two holding
tanks used to segregate waste streams. One tank
holds acidic and chromium-bearing wastes and the
other caustic and cyanide-bearing wastes. These two
tanks are used for waste equalization. Wastewater
from each of the holding tanks is then pumped to one
of two 1,100-gallon treatment tanks. One tank is for
chromium reduction using sulfur dioxide gas; the
other is for cyanide destruction using calcium hypo-
chlorite at a pH above 10. Following treatment for
chromium reduction and cyanide destruction, the
wastes flow to a tank where pH adjustment and metal
precipitation occurs. Following separation and thick-
ening, the sludge is dewatered in a filter press I to
increase the solids concentration. The sludge is stored
in metal bins prior to off-site disposal. The treated
effluent is discharged to the POTW. ,
drip bars for extending workpiece drain time. Plant B
has'developed a batch treatment program to eliminate
the need for containerizing spent baths for off-site
disposal. Nevertheless, several additional opportuni-
ties for waste reduction may be available to Plant B
that could further reduce hazardous waste generation.
DRAG-OUT LOSS REDUCTION
The chemical load on wastewater due to drag-out
loss can be reduced by operating baths at lower con-
centrations. The plant should test the effectiveness of
the process baths at lower concentrations to find the
lowest possible operating concentration that gives
acceptable results.
Drag-out loss can also be reduced by improving
operator awareness of proper workpiece rack handling
procedures. Plant personnel should be required to use
the drip bars above the process baths so that drag-out
loss can be minimized. In addition, slow workpiece
rack removal techniques should be stressed.. Plant B
should also consider extending the drain boards to
cover the space between tanks and installing drain
boards on the remaining tanks.
Spray rinse systems should be used above the pro-
cess bath as workpiece racks are removed. As the
racks are removed, they are sprayed by nozzles posi-
tioned to maximize drag-out recovery. These systems
are generally used with heated process baths since the
addition of water from the rinse system would other-
wise increase the process bath volume. Spray rinses
can also be used as a separate rinse step before dip
rinsing. If installed by plant personnel, a spray sys-
tem could cost $100 to $200. If additional tanks are
used for collecting spray solutions, the cost could
increase to $500.
Waste Reduction Recommendations DRAG-OUT RECOVERY
Plant B has effectively implemented several tech-
nologies to reduce the amount of hazardous waste that
it generates. Water conservation techniques, such'as
using multistage rinse systems and installing flow
resuictors, have allowed the plant to significantly
reduce water usage. In addition, several process lines
have closed loop rinse systems. The company
instructs personnel on the proper procedures for han-
dling workpiece racks to reduce drag-out and provides
Plant B should replenish heated process tanks with
drag-out solutions recovered in static drag-out tanks.
Most heated baths will require replenishing because of
evaporative water loss and chemical drag-out. A
drag-out tank, used as an initial rinse before the stan-
dard flow-through rinse operation, can be used to
recover lost process chemicals. Deionized water
should be used for the static rinse tank to minimize
the addition of contaminants into the process bath.
The use of a drag-out tank will also allow the flow-
52
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through rinse system to operate at a lower flow rate.
The company should identify heated baths that can be
replenished with a drag-out .solution and determine
how to rearrange process tanks to provide room for
new drag-out tanks.
A 150-gallon drag-out tank costs approximately
$400. However, Plant B could construct its own for
much less. Since Plant B already has a water pre-
treatment system, the cost for deionized water would
only include the cost of treatment per gallon. Other
costs include personnel time for the process line rear-
rangements necessary to make room for an additional
tank.
PROCESS CHEMICAL AND RINSE
WATER RECOVERY
Plant B may be able to reduce waste generation by
recovering process chemicals from several rinse water
waste streams and recycling rinse water. The plant
now operates closed loop rinse systems for four dif-
ferent chrome plating lines, but the process chemicals
captured in the ion exchange columns are not recov-
ered for reuse. Plant B should identify appropriate
ion exchange resins and regenerants that can allow the
plant to recover chromate solutions for replenishing
process baths. Plant B can reduce chemical purchase
costs, as well as waste treatment and disposal costs,
by recovering chromium solutions instead of handling
the chromium regenerant solutions as a waste.
Costs include the purchase of resins, regenerant
solutions, and holding tanks for regenerant solutions
and for recovered chromate solutions. This would not
include the cost for testing various regenerants and for
experimenting with reuse of the chromate solution.
Plant B should use process chemical and rinse
water recovery technologies on other process lines.
Approximately 2.8 percent of Plant B's sludge was
nickel. Technologies that can recover nickel salts
include reverse osmosis, ion exchange, and electro-
dialysis. Plant B should identify the sources of nickel
entering the waste stream and determine the feasibility
of recovering nickel process chemicals for reuse. By
implementing a recovery technology, Plant B may
also be able to recycle the rinse water used for the
nickel process lines.
Costs for implementing nickel salt recovery depend
on the treatment capacity requirements of the recovery
unit and the concentration of nickel salts in the waste
stream. Plant B should identify and characterize the
waste streams that carry nickel into the wastewater.
This information could then be used to choose and
size a recovery system and to estimate operating costs.
Applicable technologies for nickel salt recovery
include reverse osmosis, ion exchange, and electro-
dialysis. These technologies can cost approximately
$15,000 to $40,000, depending on the operating
requirements.
If nickel salts recovery is not feasible, Plant B
should consider electrolytic recovery of nickel.
Assuming that the sludge generated at the plant is
consistently 2.8 percent nickel by weight, approxi-
mately 5,000 pounds of nickel is disposed of annually
(based on 93.5 tons of sludge generated each year).
Depending on the concentration of nickel waste
streams, Plant B could recover metals for resale by
either installing a flow-through, high surface area
electrolytic metal recovery unit or converting a plating
bath tank to a batch treatment metal recovery tank.
Sludge analysis data indicate that tin was also pres-
ent in relatively high concentrations. The sludge was
approximately 1.5 percent tin. Although process
chemical recovery technologies such as ion exchange
and reverse osmosis are not typically applied to tin
recovery, electrolytic recovery is still applicable.
Therefore, Plant B should consider metal recovery
technologies for tin.
The type of electrolytic recovery equipment neces-
sary to recover nickel and tin depends on the concen-
tration of these metals in the waste stream. Dilute
rinse solutions require a high surface area electrolytic
metal recovery unit. Concentrated waste streams,
however, can be batch treated in an existing plating
tank when the plant can take a plating tank out of
service. The cost of batch treatment and electrolytic
metal recovery processes would, therefore, only
include construction of metal plate cathodes. Purchase
cost of a high surface area electrolytic metal recovery
unit would depend on flow rates and concentrations of
the metal-bearing waste.
53
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WASTE STREAM SEGREGATION
i
i
The plant may be able to reduce its sludge volume
by further segregating its waste streams. At the pres-
ent time, all acid and chromium-bearing wastes are
commingled. Similarly, all alkaline and cyanide
wastes are mixed. Chromium reduction and cyanide
destruction are, therefore, performed on a more diljite
and larger volume of wastewater than if chromium
wastes and cyanide wastes were treated separately
from all other waste streams. This commingling \ of
wastes before chromium and cyanide treatment niay
increase the volume of treatment sludge. ;
i
Plant B can segregate its waste streams by purchas-
ing additional holding tanks. The cost of purchasing
and installing these tanks depends on their size and
additional plumbing requirements. Plant 6 will need
to identify the flow rates for the various categories1 of
segregated wastes to determine holding capacities ifor
the tanks. !
Savings associated with segregating these wastes
for selective treatment include reduced treatment
chemical purchases and sludge handling costs.
Plant B may be able to estimate these savings by
experimenting with batch treatment of commingled
wastes and segregated wastes to determine differences
in chemical usage and sludge volume.
SLUDGE DEWATERING
Plant B can reduce sludge volume by further dewa-
tering its sludge. Wastewater treatment sludge is cur-
rently dewatered by a mechanical filter press. This
increases the solids content to approximately 35 per-
cent. The solids content of the sludge could be
increased to approximately 90 to 95 percent by using
a sludge dryer. Increasing the percent solids content
from 35 percent to 95 percent will reduce sludge vol-
ume by 60 to 65 percent. Plant B generated 93.5
cubic yards of sludge in 1987. Use of a sludge dryer
could reduce the annual sludge generation volume by
approximately 60 cubic yards.
Plant B would need to purchase a small dryer to
handle the 50 cubic feet of sludge it generates each
week. Therefore, the sludge dryer would need to pro-
cess 10 cubic feet, or 75 gallons, of sludge each day.
54
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PLANT C WASTE MINIMIZATION ASSESSMENT
Plant C specializes in zinc plating and anodizing.
The company has been in business since 1977 and
employs 30 people, 4 of whom have some responsibi-
lity for environmental compliance. Plant C operates
two and sometimes three 8-hour shifts per day. The
following discussion summarizes the findings of the
California audit team.
Process Description
Plant C operates large process baths and rinse tanks
and is, therefore, able to process large workpieces.
PROCESS BATHS
Plant C's process tanks range in size from 800 gal-
lons to 4,500 gallons. Approximately 80 percent of
the production output involves zinc plating. All pro-
cess lines are operated by automatic hoists.
Plant C uses several process bath maintenance
techniques for its zinc baths. A wetting agent is
added to the zinc baths to decrease surface tension. A
swimming pool filter removes oil and particulates
from the zinc process baths. Each bath is filtered as
needed for approximately 24 hours. Copper contami-
nants are removed from the zinc baths by dummying,
a technique based on low-current electrolytic removal.
Zinc anode balls are added to maintain the operating
concentration.
The plant replenishes its alkaline cleaning baths by
removing a portion of the bath.and restoring its vol-
ume with fresh chemicals and water. The pH of the
alkaline electrocleaner is monitored to determine the
need for replenishing. The entire bath is dumped
when replenishing becomes too frequent. The alkaline
cleaning baths are also filtered to remove particulates
and oil.
Workpiece rack handling is performed automati-
cally at Plant C using hoists. The removal rate is
preset for all operations and is maintained at approxi-
mately 1 foot per second. The drainage time for
workpiece racks is controlled by an operator, however,
and workpiece racks are allowed to drain until the
drag-out stops streaming and begins to drip.
Most of the process tanks used at Plant C are set
side by side with no space between where drag-out
solution would drain. Drain boards are used on two
of the tanks that do have space between them.
Chemical process baths are replaced when they no
longer provide the necessary process quality. The fre-
quency of bath disposal at the plant varies with the
type of bath and the amount of plating required. The
zinc process baths have not.been replaced in over
13 years. The acid stripper baths generally last from
3 months to 6 months, the alkaline cleaner baths from
6 months to 12 months, and the remaining baths one
or more years. All spent process baths are batch
treated on site.
RINSE SYSTEMS
Plant C uses both static rinse tanks and flow-
through rinse water tanks. All rinse tanks in the zinc
plating line are static tanks and are batch treated on
site. Flow-through tanks and static tanks are used on
the anodizing line and discharge directly to the sani-
tary sewer.
The plant uses several water conservation tech-
niques in its zinc plating rinse systems. One tank is
used for a rinse bath after both alkaline and acid
cleaning operations. Three other tanks are used
together as a triple rinse system. Once a week, the
rinse water in the initial rinse tank is removed and
replaced with the rinse water from the intermediate
rinse tank. Rinse water from the final rinse tank is
pumped into the intermediate tank, and then is filled
with clean rinse water.
Plant C operates both static and flow-through rinse
tanks for the anodizing line. The rinse water effluent
from the anodizing line is discharged directly to the
publicly owned treatment works (POTW) since this
rinse water does not contain metals that are regulated
under the plant's discharge permit.
Air spargers are used on several of the rinse tanks
in both the zinc plating and anodizing lines. Several
rinse tanks are not equipped with air spargers,
55
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however, because of concerns for agitating settled
contaminants and affecting product quality. i
WASTEWATER TREATMENT j
i
Plant C batch treats for its waste rinse water.
Rinse water is collected in a number of holding tanks
and tested prior to treatment. The holding tanks seg-
regate cyanide waste, chromium waste, and acidic and
alkaline waste. Wastewater containing cyanide is
treated with sodium hypochlorite to oxidize the cya-
nide. Wastewater containing chromium is treated with
sodium bisulfite to reduce the chromium. Following
these processes, caustic is added to the waste 'for
metal precipitation and pH adjustment. Polymer is
then added to aid flocculation of the precipitahts.
Effluent leaving the clarifier is filtered and discharged
to the POTW. Sludge is settled in a holding tank jand
then dewatered in a filter press to increase soiids
content to approximately 35 percent. Once the sludge
is dewatered, it is placed in a storage tank and
allowed to accumulate. Plant C generates approxi-
mately 16 cubic yards of sludge quarterly and ithe
sludge is transported off site. |
Plant C also batch treats its spent baths in a sepa-
rate treatment tank before adding the waste to the
treatment system. These wastes are treated to remove
high concentrations of metals prior to the standard
treatment process. The sludge generated from ithe
batch treatment is added to the sludge from the waste-
water treatment plant, and the supernatant is added to
the rinse water influent to the treatment plant.
Waste Reduction Recommendations
Plant C has effectively implemented a number of
waste reduction technologies. The company continu-
ally monitors its process bath life. Several rinse water
reduction techniques are used including multiple tank
rinsing, static rinsing, and air spargers. The company
also batch treats all spent process baths and segregates
waste streams for selective treatment. Nevertheless,
several additional opportunities for waste reduction
may be available to Plant C to further reduce its haz-
ardous waste generation. :
DRAG-OUT LOSS REDUCTION
Drag-out lost between several of the process tanks
should be recovered by using drain boards. Plant C
has installed drain boards between some of its process
tanks to catch drag-out and return it to the process
baths. However, the remaining tanks do not have
drain boards because plant personnel require access to
the space between these tanks to make repairs.
Removable or hinged drain boards should, therefore,
be installed.
Drag-out loss can be minimized by improving
workpiece removal and drainage procedures. Plant C
uses an automatic hoist to remove parts from the pro-
cess baths. The removal speed should be slower.
Drain time should also be controlled by a timer.
Optimal removal and drain times can be determined
by measuring drag-out that has been allowed to drain
into a pan after trying different removal speeds and
drain times. The automatic hoist can be set at the
optimal removal speed, and a timer can be used to
help operators use adequate drain time.
Capital costs would include the purchase of timers,
possible modifications to the hoist motor to allow for
a slower removal rate, and material for constructing
drain boards. The company will also need to commit
time for personnel to experiment with modified work-
piece rack removal and drain procedures.
MATERIAL SUBSTITUTION
Plant C should replace its chelated electrocleaner
with a nonchelated or mild chelated cleaner. A non-
chelated bath would produce less sludge during
treatment.
Plant C should also replace its zinc cyanide baths
with a noncyanide zinc plating chemistry. The cya-
nide baths and cyanide-contaminated rinse water
require .additional treatment to destroy the cyanide.
The company now uses sodium hypochlorite to treat
the cyanide wastes. Caustic is used to raise the pH
prior to treatment. According to other metal finishers,
replacement chemistries are available for zinc baths.
By using these chemistries, the plant would not need
56
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to use cyanide treatment and could reduce its waste
treatment costs by avoiding the cyanide oxidation
treatment step.
The use of nonchelated cleaners may require the
process bath to be continually filtered. Filter systems
cost between $400 and $1,000. Such a system would
include a water pump, filters, and associated piping.
However, depending on the actual requirements of the
cleaning bath, Plant C may be able to operate with
only periodic filtering using an existing filter system.
Savings from using nonchelated and noncyanide
chemistries include reduced waste treatment and
sludge handling costs. Plant C can test alternative
process chemistries and batch treat the resultant waste
to determine the effect these alternative process chem-
icals have on reducing sludge volume.
WASTE REUSE
Plant C should reuse spent acid and alkaline baths
for waste treatment. The company now batch treats
its spent acid and alkaline baths with virgin chemicals.
These spent process baths could be used for pH
adjustment prior to cyanide destruction and chromium
reduction. The company could also use spent acids to
neutralize the spent alkaline baths, if the baths are
compatible. Plant C should determine which of the
acidic and alkaline process baths would be best for pH
adjustment prior to chromium reduction or cyanide
destruction. The remaining spent acidic and alkaline
baths should be used to neutralize each other, if the
baths are compatible. The plant may have to synchro-
nize its dump schedules for these baths to ensure
availability and to minimize the length of time spent
baths would have to be stored prior to reuse.
Costs associated with using process bath wastes for
wastewater treatment include the purchase of holding
tanks and the time required to test various treatment
options. Holding tanks for the spent baths could cost
between $400 and $600 for 150- to 400-gallon tanks.
The effectiveness of the spent process baths for waste-
water treatment can be tested on a batch treatment
basis in the treatment system. Significant savings can
be expected from reusing spent baths for wastewater
treatment and will include reduced treatment chemical
purchases and sludge generation.
WASTEWATER TREATMENT
Several potential wastewater treatment modifica-
tions are available to Plant C that provide opportuni-
ties for sludge volume reduction. The company gen-
erates over 60 cubic yards of sludge annually.
Although no sludge characterization data were avail-
able to assess the efficiency of the existing treatment
system, it appears that modifications to the system
could reduce sludge volume.
The plant treats chromium wastes with sodium
bisulfite to reduce chromium. This requires the pH of
the waste stream to be between 2.0 and 2.5. The
acids used to drop the pH and the caustic used to raise
it for metal precipitation contribute to sludge volume.
The company should consider reductions with ferrous
sulfate, which does not require pH adjustments down
to 2.0. Although the resulting ferric ions will precipi-
tate out and contribute to sludge volume, often the
contribution is not as great as the pH adjustment
chemicals used for bisulfite reduction. Plant C should
evaluate its existing chromium treatment process to
determine if alternative treatment chemicals could be
used to reduce sludge volume.
Plant C should also consider electrolytic recovery
of zinc from its spent process bath and rinse solutions.
The plant now batch treats its spent zinc solutions to
precipitate metals. Some spent solutions contain zinc
in concentrations as high as 80,000 parts per million.
These solutions could be electrolytically treated to
recover the zinc. The company could use an existing
plating tank. By inserting numerous metal boards into
the spent solution and running a current through it,
plant personnel can recover the zinc in the spent
solution.
SLUDGE DEWATERING
Plant C can significantly reduce its sludge disposal
costs by dewatering its industrial waste treatment
sludge. The plant generates approximately 35 cubic
feet of sludge per week (7 cubic feet per day). There-
fore, a sludge dryer with a treatment capacity of 1.0 to
1.5 cubic feet per hour is appropriate. A continuous
feed dryer appears necessary to minimize labor costs.
A dryer of this type, which uses either natural gas or
propane as a fuel source, would cost approximately
57
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$27,000, not including the cost for a propane tank. If
the unit operated 5 hours a day, 5 days a week,
operating costs for a unit fueled by propane would be
approximately $1,500 per year. The operating costs
do not include labor.
Plant C currently pays approximately $16,000 per
year to dispose of its industrial waste sludge. How-
ever, this figure does not include state and federal
costs by $67 per cubic yard (a $4,200 increase in
Plant C's annual disposal costs). If a dryer achieved a
2.5-to-l reduction in sludge volume, annual disposal
costs would be reduced by approximately $10,000
($12,100 if taxes are considered). After subtracting
the annual operating costs, annual savings would be
approximately $8,500. This represents approximately
a 3-year payback on investment. The payback time
would be 2.5 years if waste taxes are included in the
hazardous waste taxes, which could increase disposal cost of sludge disposal.
58
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Appendix B
WHERE TO GET HELP:
FURTHER INFORMATION ON POLLUTION PREVENTION
Additional information on source reduction, reuse
and recycling approaches to pollution prevention is
available in EPA reports listed in this section, and
through state programs and regional EPA offices
(listed below) that offer technical and/or financial
assistance in the areas of pollution prevention and
treatment.
Waste exchanges have been established in some
areas of the U.S. to put waste generators in contact
with potential users of the waste. Twenty-four
exchanges operating in the U.S. and Canada are listed.
Finally, relevant industry associations are listed.
U.S. EPA Reports on
Waste Minimization
Facility Pollution Prevention Guide.
92/088.*
EPA/600/R-
Waste Minimization Opportunity Assessment Manual.
EPA/625/7-88/003.*
Waste Minimization Audit Report: Case Studies of
Corrosive and Heavy Metal Waste Minimization Audit
at a Specialty Steel Manufacturing Complex. Execu-
tive Summary. EPA No. PB88-107180.**
Waste Minimization Audit Report: Case Studies of
Minimization of Solvent Waste for Parts Cleaning and
from Electronic Capacitor Manufacturing Operation.
Executive Summary. EPA NO. PB87-227013.**
* Available from EPA CERI Publications Unit (513) 569-7562,
26 West Martin Luther King Drive, Cincinnati, OH, 45268.
** Executive Summary available from EPA, CERI Publications
Unit, (513) 569-7562, 26 West Martin Luther King Drive, Cin-
cinnati, OH, 45268; full report available from the National
Technical Information Service (NTIS), U.S. Department of
Commerce, Springfield, VA, 22161.
Waste Minimization Audit Report: Case Studies of
Minimization of Cyanide Wastes from Electroplating
Operations. Executive Summary. EPA No. PB87-
229662.** ,, .,
Report to Congress: Waste Minimization, Vols. I and
II. EPA/53Q-SW-86-033 and -034 (Washington, D.C.:
U.S. EPA, 1986).***
Waste Minimization—Issues and Options, Vols. I-III.
EPA/530-SW-86-041 through -043. (Washington,
D.C.: U.S. EPA, 1986.)***
The Guides to Pollution Prevention manuals*
describe waste minimization options for specific
industries. This is a continuing series which currently
includes the following titles:
Guides to Pollution Prevention: Paint Manufacturing
Industry. EPA/625/7-90/005.
Guides to Pollution Prevention: The Pesticide For-
mulating Industry. EPA/625/7-90/004.,
Guides to Pollution Prevention: The Commercial
Printing Industry. EPA/625/7-90/008.
Guides to Pollution Prevention: The Fabricated
Metal Industry. EPA/625/7-90/006.
Guides to Pollution Prevention for Selected Hospital
Waste Streams. EPA/625/7-90/009.
Guides to Pollution Prevention: Research and Educa-
tional Institutions. EPA/625/7-90/010.
Guides to Pollution Prevention: The Printed Circuit
Board Manufacturing Industry. EPA/625/7-90/007.
*** Available from the National Technical Information Service as
a five-volume set, NTIS No. PB-87-114-328.
59
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Guides to Pollution Prevention:
Industry. EPA/625/7-91/017.
Guides to Pollution Prevention:
Industry. EPA/625/7-91/012.
The Pharmaceutical For more information contact:
The Photoprocessing
Guides to Pollution Prevention: The Fiberglass Rein-
forced and Composite Plastic Industry. \
EPA/625/7-91/014. ;
Guides to Pollution Prevention: The Automotive
Repair Industry. EPA/625/7-91/013. |
|
Guides to Pollution Prevention: The Automotive
Refmlshing Industry. EPA/625/7-91/016. |
Guides to Pollution Prevention: The Marine Mainte-
nance and Repair Industry. EPA/625/7-91/015. !
Guides to Pollution Prevention: The Metal Casting
and Heat Treating Industry. \
•• [
Guides to Pollution Prevention: Mechanical Equip-
ment Repair Shops. \
Guides to Pollution Prevention:
Industry.
The Metal Finishing
U.S. EPA Pollution Prevention Information Clearing
House (PPIC): Electronic Information Exchange Sys-
tem (EIES}—User Guide, Version 1.1. EPA/600/9-
89/086. ;
Waste Reduction Technical/
Financial Assistance Programs j
The EPA Pollution Prevention Information Clear-
inghouse (PPIC) was established to encourage waste
reduction through technology transfer, education, and
public awareness. PPIC collects and disseminates
technical and other information about pollution pre-
vention through a telephone hotline and an electronic
information exchange network. Indexed bibliographi-
es and abstracts of reports, publications, and case
studies about pollution prevention are available. PPIC
also lists a calendar of pertinent conferences and semi-
nars, information about activities abroad, and a direc-
tory of waste exchanges. Its Pollution Prevention
Information Exchange System (PIES) can be accessed
electronically 24 hours a day without fees. j
PIES Technical Assistance
Science Applications International Corp.
8400 Westpark Drive
McLean, VA 22102
(703)821-4800
or
U.S. Environmental Protection Agency
401 M Street S.W.
Washington, D.C. 20460
Myles E. Morse
Office of Environmental Engineering and
Technology Demonstration
(202)475-7161
Priscilla Flattery
Pollution Prevention Office
(202)245-3557
The EPA's Office of Solid Waste and Emergency
Response has a telephone call-in service to answer
questions regarding RCRA and Superfund (CERCLA).
The telephone numbers are:
(800) 242-9346 (outside the District of Columbia)
(202) 382-3000 (in the District of Columbia)
The following programs offer technical and/or
financial assistance for waste minimization and
treatment.
Alabama
Hazardous Material Management and Resource
Recovery Program
University of Alabama
P.O. Box 6373
Tuscaloosa, AL 35487-6373
(205) 348-8401
Department of Environmental Management
1751 Federal Drive
Montgomery, AL 36130
(205)271-7914
60
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Alaska
Alaska Health Project
Waste Reduction Assistance Program
431 West Seventh Avenue, Suite 101
Anchorage, AK 99501
(907) 276-2864
Arizona
Arizona Department of Economic Planning and
Development
1645 West Jefferson Street
Phoenix, AZ 85007
(602)255-5705
Arkansas
Arkansas Industrial Development Commission
One State Capitol Mall
Little Rock, AR 72201
(501) 371-1370
California
Alternative Technology Section
Toxic Substances Control Division
California State Department of Health Services
714/744 P Street
Sacramento, CA 94234-7320
(916) 324-1807
Pollution Prevention Program
San Diego County Department of Health Services
Hazardous Materials Management Division
P.O. Box 85261
San Diego, CA 92186-5261
(619) 338-2215
Colorado
Division of Commerce and Development Commission
500 State Centennial Building
Denver, CO 80203
(303) 866-2205
Connecticut
Connecticut Hazardous Waste Management Service
Suite 360
900 Asylum Avenue
Hartford, CT 06105
(203) 244-2007
Connecticut Department of Economic Development
210 Washington Street
Hartford, CT 06106
(203) 566-7196
Delaware
Delaware Department of Community Affairs &
Economic Development
630 State College Road
Dover, DE 19901
(302) 736-4201
District of Columbia
U.S. Department of Energy
Conservation and Renewable Energy
Office of Industrial Technologies
Office of Waste Reduction, Waste Material
Management Division
Bruce Cranford CE-222
Washington, DC 20585
(202) 586-9496
Pollution Control Financing Staff
Small Business Administration
1441 "L" Street, N.W., Room 808
Washington, DC 20416
(202) 653-2548
Florida
Waste Reduction Assistance Program
Florida Department of Environmental Regulation
2600 Blair Stone Road
Tallahassee, FL 32399-2400
(904) 488-0300
Georgia
Hazardous Waste Technical Assistance Program
Georgia Institute of Technology
Georgia Technical Research Institute
Environmental Health and Safety Division.
O'Keefe Building, Room 027
Atlanta, GA 30332
(404) 894-3806
Environmental Protection Division
Georgia Department of Natural Resources
205 Butler Street, S.E., Suite 1154
Atlanta, GA 30334
(404)656-2833 . • - .
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Guam
Solid and Hazardous Waste Management Program i
Guam Environmental Protection Agency
IT&E Harmon Plaza, Complex Unit D-107 :
130 Rojas Street i
Harmon, Guam 96911 i
(671) 646-8863-5 :
Hawaii
Department of Planning & Economic Development
Financial Management and Assistance Branch i
P.O. Box 2359 !
Honolulu, HI 96813 ;
(808) 548-4617
Idaho
IDHW-DEQ l
Hazardous Materials Bureau j
450 West State Street, 3rd Floor !
Boise, ID 83720 i
(208) 334-5879 j
i
Illinois
Illinois EPA !
Office of Pollution Prevention
2200 Churchill Road
P.O. Box 19276 |
Springfield, Illinois 62794-9276
(217) 782-8700 I
Hazardous Waste Research and Information Center;
Illinois Department of Energy and Natural Resources
One East Hazelwood Drive ;
Champaign, IL 61820 I
(217) 333-8940
i
• i
Illinois Waste Elimination Research Center
Pritzker Department of Environmental Engineering;
Alumni Memorial Hall, Room 103 j
Illinois Institute of Technology
3201 South Dearborn j
Chicago, IL 60616 j
(312)567-3535 ',
Indiana
Environmental Management and Education Program
School of Civil Engineering
Purdue University
2129 Civil Engineering Building
West Lafayette, IN 47907
(317) 494-5036
Indiana Department of Environmental Management
Office of Technical Assistance
P.O. Box 6015
105 South Meridian Street
Indianapolis, IN 46206-6015
(317) 232-8172
Iowa
Center for Industrial Research and Service
Iowa State University
Suite 500, Building 1
2501 North Loop Drive
Ames, IA 50010-8286
(515) 294-3420 :
Iowa Department of Natural Resources
Air Quality and Solid Waste Protection Bureau
Wallace State Office Building
900 East Grand Avenue
Des Moines, IA 50319-0034
(515) 281-8690
Waste Management Authority
Iowa Department of Natural Resources
Henry A. Wallace Building
900 East Grand
Des Moines, IA 50319
(515) 281-8489
Iowa Waste Reduction Center
University of Northern Iowa
75 Biology Research Complex
Cedar Falls, IA 50614
(319) 273-2079
Kansas
Bureau of Waste Management
Department of Health and Environment
Forbes Field, Building 730
Topeka, KS 66620
(913)269-1607
Kentucky
Division of Waste Management
Natural Resources and Environmental Protection
Cabinet
18 Reilly Road
Frankfort, KY 40601
(502) 564-6716
62
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Kentucky Partners
Room 312 Ernst Hall
University of Louisville
Speed Scientific School
Louisville, KY 40292
(502)588-7260
Louisiana
Department of Environmental Quality
Office of Solid and Hazardous Waste
P.O. Box 44307
Baton Rouge, LA 70804
(504) 342-1354
Maine
State Planning Office
184 State Street
Augusta, ME 04333
(207) 289-3261
Maryland
Maryland Hazardous Waste Facilities Siting Board
60 West Street, Suite 200 A
Annapolis, MD 21401
(301) 974-3432
Massachusetts
Office of Technical Assistance
Executive Office of Environmental Affairs
100 Cambridge Street, Room 1904
Boston, MA 02202
(617) 727-3260
Source Reduction Program
Massachusetts Department of Environmental
Quality Engineering
1 Winter Street
Boston, MA 02108
(617) 292-5982
Michigan
Resource Recovery Section
Department of Natural Resources
P.O. Box 30028
Lansing, MI 48909
(517)373-0540
Minnesota
Minnesota Pollution Control Agency
Solid and Hazardous Waste Division
520 Lafayette Road
St. Paul, MN 55155
(612) 296-6300
Minnesota Technical Assistance Program
1313 5th Street, S.E., Suite 207
Minneapolis, MN 55414
(612) 627-4646
(800) 247-0015 (in Minnesota)
Mississippi
Waste Reduction & Minimization Program
Bureau of Pollution Control
Department of Environmental Quality
P.O. Box 10385
Jackson, MS 39289-0385
(601) 961-5190
Missouri
State Environmental Improvement and Energy
Resources Agency
P.O. Box 744
Jefferson City, MO 65102
(314)751-4919
Waste Management Program
Missouri Department of Natural Resources
Jefferson Building, 13th Floor
P.O. Box 176
Jefferson City, MO 65102
(314)751-3176
Nebraska
Land Quality Division
Nebraska Department of Environmental Control
Box 98922
State House Station
Lincoln, ME 68509-8922
(402) 471-2186
Hazardous Waste Section
Nebraska Department of Environmental Control
P.O. Box 98922
Lincoln, ME 68509-8922
(402) 471-2186
63
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New Jersey
New Jersey Hazardous Waste Facilities Siting
Commission
Room 514
28 West State Street
Trenton, NJ 08625
(609) 292-1459
(609) 292-1026
Hazardous Waste Advisement Program
Bureau of Regulation and Classification
New Jersey Department of Environmental Protection
401 East State Street '
Trenton, NJ 08625
(609) 292-8341
Risk Reduction Unit
Office of Science and Research :
New Jersey Department of Environmental Protection
401 East State Street i
Trenton, NJ 08625 '
(609) 292-8341 ;
[
New Mexico
Economic Development Department i
Bataan Memorial Building
State Capitol Complex
Santa Fe, NM 87503
(505) 827-6207 I
New York I
New York Environmental Facilities Corporation i
50 Wolf Road !
Albany, NY 12205
(518) 457-4222 !
North Carolina
Pollution Prevention Pays Program j
Department of Natural Resources and Community ;
Development ;
P.O. Box 27687
512 North Salisbury Street
Raleigh, NC 27611-7687
(919) 733-7015
Governor's Waste Management Board
P.O. Box 27687 i
325 North Salisbury Street
Raleigh, NC 27611-7687
(919) 733-9020
Technical Assistance Unit
Solid and Hazardous Waste Management Branch
North Carolina Department of Human Resources
P.O. Box 2091
306 North Wilmington Street
Raleigh, NC 27602
(919) 733-2178
North Dakota
North Dakota Economic Development Commission
Liberty Memorial Building
State Capitol Grounds
Bismarck, ND 58505
(701) 224-2810
Ohio
Division of Hazardous Waste Management
Division of Solid and Infectious Waste Management
Ohio Environmental Protection Agency
P.O. Box 0149
1800 Watermark Drive
Columbus, OH 43266-0149
(614) 644-2917
Oklahoma
Industrial Waste Elimination Program
Oklahoma State Department of Health
P.O. Box 53551
Oklahoma City, OK 73152
(405) 271-7353
Oregon
Oregon Hazardous Waste Reduction Program
Department of Environmental Quality
811 Southwest Sixth Avenue
Portland, OR 97204
(503)229-5913
(800) 452-4011 (in Oregon)
Pennsylvania
Pennsylvania Technical Assistance Program
501 F. Orvis Keller Building
University Park, PA 16802
(814) 865-0427
Center of Hazardous Material Research
Subsidiary of the University of Pittsburgh Trust
320 William Pitt Way
Pittsburgh, PA 15238
(412) 826-5320
(800) 334-2467
64
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Puerto Rico
Government of Puerto Rico "
Economic Development Administration
Box 2350
San Juan, PR 00936
(809) 758-4747
Rhode Island
Hazardous Waste Reduction Section
Office of Environmental Management
83 Park Street
Providence, RI 02903
(401) 277-3434
(800) 253-2674 (in Rhode Island)
South Carolina
Center for Waste Minimization
Department of Health and Environmental Control
2600 Bull Street
Columbia, SC 29201
(803) 734-4715
South Dakota
Department of State Development
P.O. Box 6000
Pierre, SD 57501
(800)843-8000
Tennessee
Center for Industrial Services
University of Tennessee
Building #401
226 Capitol Boulevard
Nashville, TN 37219-1804
(615) 242-2456
Bureau of Environment
Tennessee Department of Health and Environment
150 9th Avenue North
Nashville, TN 37219-5404
(615) 741-3657
Tennessee Hazardous Waste Minimization Program
Tennessee Department of Economic and Community
Development
Division of Existing Industry Services
7th Floor, 320 6th Avenue, North
Nashville, TN 37219
(615) 741-1888
Texas
Texas Economic Development Authority
410 East Fifth Street
Austin, TX 78701
(512) 472-5059
Utah
Utah Division of Economic Development
6150 State Office Building
Salt Lake City, UT 84114
(801) 533-5325
Vermont
Economic Development Department
Pavilion Office Building
Montpelier, VT 05602
(802) 828-3221
Virginia
Office of Policy and Planning
Virginia Department of Waste Management
11th Floor, Monroe Building
101 North 14th Street
Richmond, VA 23219
(804) 225-2667
Washington
Hazardous Waste Section
Mail Stop PV-11
Washington Department of Ecology
Olympia, WA 98504-8711
(206) 459-6322
West Virginia
Governor's Office of Economics and Community
Development
Building G, Room B-517
Capitol Complex
Charleston, WV 25305
(304) 348-2234
Wisconsin
Bureau of Solid Waste Management
Wisconsin Department of Natural Resources
P.O. Box 7921
101 South Webster Street
Madison, WI 53707
(608) 267-3763
65
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Wyoming
Solid Waste Management Program
Wyoming Department of Environmental Quality
Herschler Building, 4th Floor, West Wing
122 West 25th Street
Cheyenne, WY 82002
(307) 777-7752
Waste Exchanges
Alberta Waste Materials Exchange
Mr. William C. Kay
Alberta Research Council
P.O. Box 8330
Postal Station F
Edmonton, Alberta
CANADA T6H5X2
(403) 450-5408
British Columbia Waste Exchange
Ms. Judy Toth
2150 Maple Street
Vancouver, B.C.
CANADA V6J3T3
(604) 731-7222
California Waste Exchange
Mr. Robert McCormick
Department of Health Services
Toxic Substances Control Program
Alternative Technology Division
P.O. Box 942732
Sacramento, CA 94234-7320
(916) 324-1807
Canadian Chemical Exchange*
Mr. Philippe LaRoche
P.O. Box 1135
Ste-Adele, Quebec
CANADA JOR 1LO
(514)229-6511
Canadian Waste Materials Exchange
ORTECH International
Dr. Robert Laughlin
2395 Speakman Drive
Mississauga, Ontario
CANADA L5K 1B3
(416)822-4111 (Ext. 265)
FAX: (416)823-1446
Enstar Corporation*
Mr. J. T. Engster
P.O. Box 189
Latham, NY 12110
(518) 785-0470
Great Lakes Regional Waste Exchange
400 Ann Street, N.W., Suite 204
Grand Rapids, MI 49504
(616) 363-3262
Indiana Waste Exchange
Dr. Lynn A. Corson
Purdue University
School of Civil Engineering
Civil Engineering Building
West Lafayette, IN 47907
(317) 494-5036
Industrial Materials Exchange
Mr. Jerry Henderson
172 20th Avenue
Seattle, WA 98122
(206) 296-4633
FAX: (206) 296-0188
Industrial Materials Exchange Service
Ms. Diane Shockey
P.O. Box 19276
Springfield, IL 62794-9276
(217) 782-0450
FAX: (217)524-4193
Industrial Waste Information Exchange
Mr. William E. Payne
New Jersey Chamber of Commerce
5 Commerce Street
Newark, NJ 07102
(201) 623-7070
Manitoba Waste Exchange
Mr. James Ferguson
c/o Biomass Energy Institute, Inc.
1329 Niakwa Road
Winnipeg, Manitoba
CANADA R2J3T4
(204)257-3891
*For-Profit Waste Information Exchange
66
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Montana Industrial Waste Exchange
Mr. Don Ingles
Montana Chamber of Commerce
P.O. Box 1730
Helena, MT 59624
(406) 442-2405
New Hampshire Waste Exchange
Mr. Gary J. Olson
c/o NHRRA
P.O. Box 721
Concord, NH 03301
(603) 224-6996
Northeast Industrial Waste Exchange, Inc.
Mr. Lewis Cutler
90 Presidential Plaza, Suite 122
Syracuse, NY 13202
(315) 422-6572
FAX: (315)422-9051
Ontario Waste Exchange
ORTECH International
Ms. Linda Varangu
2395 Speakman Drive
Mississauga, Ontario
CANADA L5K 1B3
(416) 822-4111 (Ext. 512)
FAX: (416) 823-1446
Pacific Materials Exchange
Mr. Bob Smee
South 3707 Godfrey Boulevard
Spokane, WA 99204
(509) 623-4244
Peel Regional Waste Exchange
Mr. Glen Milbury
Regional Municipality of Peel
10 Peel Center Drive
Brampton, Ontario
CANADA L6T4B9
(416) 791-9400
RENEW
Ms. Hope Castillo
Texas Water Commission
P.O. Box 13087
Austin, TX 78711-3087
(512) 463-7773
FAX: (512)463-8317
San Francisco Waste Exchange
Ms. Portia Sinnott
2524 Benvenue #35
Berkeley, CA 94704
(415) 548-6659
Southeast Waste Exchange
Ms. Maxie L. May
Urban Institute
UNCC Station
Charlotte, NC 28223
(704) 547-2307
Southern Waste Information Exchange
Mr. Eugene B. Jones
P.O. Box 960
Tallahassee, FL 32302
(800) 441-SWIX (7949)
(904) 644-5516
FAX: (904)574-6704
Tennessee Waste Exchange
Ms. Patti Christian
226 Capital Boulevard, Suite 800
Nashville, TN 37202
(615) 256-5141
FAX: (615) 256-6726
Wastelink, Division of Tencon, Inc.
Ms. Mary E. Malotke
140 Wooster Pike
Milford, OH 45150
(513) 248-0012
FAX: (513)-248-1094
U.S. EPA Regional Offices
Region 1 (VT, NH, ME, MA, CT, RI)
John F. Kennedy Federal Building
Boston, MA 02203
(617) 565-3715
Region 2 (NY, NJ, PR, VI)
26 Federal Plaza
New York, NY 10278
(212) 264-2525
67
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Region 3 (PA, DE, MD, WV, VA, DC)
841 Chestnut Street
Philadelphia, PA 19107
(215) 597-9800
Region 4 (KY, TN, NC, SC, GA, FL, AL, MS)
345 Courtland Street, N.E.
Atlanta, GA 30365
(404) 347-4727
Region 5 (WI, MN, MI, IL, IN, OH)
230 South Dearborn Street
Chicago, IL 60604
(312) 353-2000
Region 6 (NM, OK, AR, LA, TX)
1445 Ross Avenue
Dallas, TX 75202
(214) 655-6444
Region 7 (NE, KS, MO, IA)
756 Minnesota Avenue
Kansas City, KS 66101
(913) 236-2800
Region 8 (MT, ND, SD, WY, UT, CO)
999 18th Street
Denver, CO 80202-2405
(303) 293-1603
Region 9 (CA, NV, AZ, ffl, GU)
75 Hawthorne Street
San Francisco, CA 94105
(415) 744-1305
Region 10 (AK, WA, OR, ID)
1200 Sixth Avenue
Seattle, WA 98101
(206) 442-5810
Industry & Trade Associations
National Association of Metal Finishers (NAMF)
111 East Wacker Drive, Suite 600
Chicago, EL 60601
(312) 644-6610
American Electroplaters and Surface Finishers Society
(AESF)
12644 Research Parkway
Orlando, FL 32826-3298
(407) 281-6441
Metal Finishing Suppliers' Association (MFSA)
801 North Cass Avenue
Westmont, IL 60559
(708) 887-0797
Videos
Management Training in Pollution Prevention and
Control in the Metal Finishing Industry
Environment Canada, 1991
Canadian Water and Wastewater Association
24 Clarence Street, 3rd Floor
Ottawa, Ontario, Canada KIN 5P3
(613) 238-5692
Rinsing Process Modifications for Metal Finishers
U.S. EPA Region DC, Terrence Foecke and Peer
Consultants
Release date to be announced
Attention: Ben Machol
Library
U.S. EPA Region DC
75 Hawthorne Street, 13th Floor
San Francisco, California 94105
(415) 744-1941
Available through the PPIC after release date
Cost: Free
68
•&U.S. GOVERNMENT PRINTING OFFICE: 1993 - 550-001/80309
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United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
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