&EPA
United States Risk Reduction Engineering Laboratory EPA/625/7-90'005
Environmental Protection Center for Environmental Research Information June 1990
Agency Cincinnati, Ohio 45268
Technology Transfer
Guides to Pollution
Prevention
The Paint Manufacturing
Industry
Printed on Recycled Paper
-------
-------
EPA/625/7-90/005
June 1990
GUIDES TO POLLUTION PREVENTION:
The Paint Manufacturing Industry
RISK REDUCTION ENGINEERING LABORATORY
AND
CENTER FOR ENVIRONMENTAL RESEARCH INFORMATION
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
-------
NOTICE
TO* guide has been subjected to U.S. Environmental **"*"
pSadministnalveTeview
.men,^
commercial products constitute endorsement or lecommendation for u^
SSS^towW^^
^developing approaches for pollution prevention. Compliance w«h
e^vS^talaiSoccupational safety and health laws is theresponsibJity
of each individual business and is hot the focus of this document
Worksheets areprovided for conducting waste minimization assessments of
paintmanufacturingfacffities. Users areencouraged to duplicate portions of
tfc publication as needed to implement a waste ininimizaoon program.
-------
FOREWORD
Paint manufacturing facilities generate largequantities of both hazardous anil
nonhazardous wastes. These wastes are eqtupmentcleaningwastewaterand
wastesolvent, filter cartridges, off-specpaintspills, leftovercontainers, and
pigment dusts from airpollution control equipment Reducing the generation
of these wastes atthesourceorrecycling the wastes on-or off-site will benefit
paintmanufacturers by leducingraw material needs.reducing disposal costs,
and lowering the liabilities associated with hazardous waste disposal
This guide provides an overview of the paint manufacturing processes and
operations that generate waste and presents options for minimizing waste
genration through source reduction and recycling.
-------
ACKNOWLEDGMENTS
This guide is based in part on waste minimization assessments conducted by
XSwtaedagG^^
ofHealthServices(DHS). Contributorstotheseassessmentsinclude: DavidLeu,
Ben^Fries,KmiWilhe^^
Section of DHS. Much of the information in this guide that provides a national
perspective on the issues of waste generation and minimization for parnt
manrfacturers was provided originally to the U.S. Environmental Protection
Agencyby Versar.Inc.andJacobsEngineeringCiroupInc. in"WasteMinrauzation-
IsSmd Options, Volume H, • Report No. PB87-114369 (1986). Jacobs
EnrineeringGroupInc.editedanddeveloped thisversionof thewasteminimization
assessment Tguide under subcontract to Radian Corporation (USEPA Contract
68-02-4286).
LisaNLBrownofmeU.S.EnviroiimentalPnjtectionAgency,OfficeofR.esBarch
and Development, Risk Reduction Engineering Laboratory, was the project
officer responsible for the preparation and review of this document . Harry
Reeman,RiskReductionEngineeringLaboratory, EPA; Benjamin Fnes, DHS;
JenyKohl,DepartmentofNiKlearEngrneerrng,Nor^
RobertNelson, National Paintand Coatings Association, Washington, D.C.; Joe
Seaton, LUly Industrial Coatings. Montebello, California; and Arnold Hoffman,
MajorPamtCo.,Tonance,C^liforiuacontributedandservedasrevieweirsofthis
guide.
rv
-------
CONTENTS
SECTION PAGE
Notice ii
Foreword l..~ iii
Acknowledgments „ -iv
1. Introduction 1
2. Paint Manufacturing Industry Profile 5
3. Waste Minimization Options for Paint Manufacturers 9
4. Guidelines for using the Worksheets 14
APPENDIX A:
Case Studies of Paint Manufacturing Plants 30
APPENDIX B:
Where to Get Help; Further Information on
Waste Minimization 63
-------
-------
SECTION!
INTRODUCTION
This guide is designed to provide paint manufacturers
with waste minimization options appropriate for this in-
dustry. It also provides worksheets designed to be used for
a waste minimization assessment of a paint manufacturing
facility, to develop an understanding of the facility's waste
generating processes and to suggest ways that the waste
may be reduced. Besides paint manufacturing plant opera-
tors and environmental engineers, this document may be
useful to our regulatory agency representatives and con-
sultants.
The worksheets and the list of waste minimization
options were developed through assessments of two Los
Angeles area paint manufacturing firms commissioned by
the California Department of Health Services (Calif. DHS
1987). The two firms' operations, manufacturing proc-
esses, and waste generation and management practices
were surveyed, and their existing and potential waste
minimization options were characterized. Economic
analyses were performed on selected options.
Reducing waste is a high priority for the paint manu-
facturing industry. In 1981, U.S. paint, coating, and ink
manufacturers represented 44 percent of the market for
solvents (Pace 1983). Solvents are used in the industry as
carriers for resins and pigments and to clean the various
process equipment used for production. Although clean-
ing solvents are often distilled and reused, a residual paint
sludge remains, which contains solvents and in some cases,
toxic metals such as mercury, lead and chromium. De-
pending on the constituents, the wastes could be consid-
ered RCRA wastes F002 (halogenated solvents), F003
(non-halogenated solvents such as acetone and xylene),
F004 (non-halogenated solvents such as cresols, cresylic
acid, nitrobenzene, and solvent blends), or F005 (non-
halogenated solvents such as toluene, methyl ethyl ketone,
and benzene). These wastes are currently banned from
land disposal.
The amount of wastes disposed of by paint manufac-
turers is high. For example, in 1984 the paint manufactur-
ing industry in California disposed of 21,000 tons of
solvent bearing waste off-site, making this industry the
highest-volume generator of manifested solvent wastes in
that year (ICF1986).
Waste minimization is a policy specifically mandated
by the U.S. Congress in the 1984 Hazardous and Solid
Wastes Amendments to the Resource Conservation and
Recovery Act (RCRA). As the federal agency responsible
for writing regulations under RCRA, the U.S. Environ-
mental Protection Agency (EPA) has an interest in ensur-
ing that new methods and approaches are developed for
minimizing hazardous 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 hazardous waste minimization.
The options and procedures outlined can also be used
in efforts to minimize other wastes generated in a facility.
EPA has also developed a general manual for waste
minimization in industry. The Waste Minimization Op-
portunity Assessment Manual (USEPA1988) tells how to
conduct a waste minimization opportunity assessment and
develop options for reducing hazardous waste generation
at a facility. It explains the management strategies needed
to incorporate waste minimization into company policies
and structure, how to establish a company-wide waste
minimization program, conduct assessments, implement
options, and make the program an on-going one. The
elements of waste minimization assessment are explained
in the Overview, next section.
In the following sections of this manual you will find:
• An overview of thepaintmanufacturing industry
and the processes used by the industry (Section
Two);
• Waste minimization options for paint
manufacturers (Section three);
• Waste Minimization Assessment Guidelines
and Worksheets (Section Four)
• An Appendix, containing:
- Case studies of waste generation and waste
minimization practices of two paint
manufacturers;
- Where to get help: additional sources of
information.
-------
Overview of Waste Minimization
Assessment
In theworkingdefinitionusedbyEPA, waste minimi-
zation consists of source reduction and recycling. Of the
two approaches, source reduction is usually considered
preferabletorecyclingfromanenvironmentalperspective.
Treatment of hazardous waste is considered an approach
towastejninimizationbysomestatesbutnotbyothers,and
thus is not addressed in this guide.
A Waste Minimization Opportunity Assessment
(WMOA),sometimes<^edawasteminimizationaudit,is
a systematic procedure for identifying ways to reduce or
eliminatewaste. The steps involved in conducting a waste
minimization assessment are outlined in Figure 1 and
presentedinmoredetailinthenextparagraphs.Brieny.the
assessment consists of a careful review of a plant's opera-
tions and waste streams and the selection of specific areas
to assess. After a particular waste stream or area is
established as the WMO A focus, a number of options with
therratemialtomtaimizewastearedevelopedandscreened.
The technical and economic feasibility of the selected
options are then evaluated. Finally, the most promising
options are selected for implementation.
To determine whether a WMOA would be useful in
your circumstances, you should first read this section
describing the aims and essentials of the WMOA process.
For more detailed information on conducting a WMOA,
consult the Waste Minimization Opportunity Assessment
Manual.
The four phases of a waste minimization assessment
are:
• Planning and organization
• Assessment phase
• Feasibility analysis phase
• Implementation
PLANNING AND ORGANIZATION
Essential elements of planning and organization for a
waste minimization program are: getting management
commitment for the program; setting waste minimization
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. Informa-
tion about waste streams may be available on hazardous
waste manifests. National Pollutant Discharge Elimina-
tion System (NPDES) reports, routine sampling programs
and other sources.
Developing a basic understanding of the processes that
generate waste at a facility is essential to the WMOA
process How diagrams should be prepared to identify the
quantity, types and rates of waste generating processes.
Also, preparing material balances for various processes
can be useful in tracking various process components and
identifying losses or emissions that may have been unac-
counted for previously.
Prioritize and select assessment targets. Ideally, all waste
streams in afacility shouldbeevaluated forpotential waste
minimization opportunities. With limited resources,
however, a plant manager may need to concentrate waste
minimization efforts in a specific area. Such considera-
tions as quantity of waste, hazardous properties of the
waste, regulations, safety of employees, economics, and
other characteristics need to be evaluated hi selecting a
target stream.
Select assessment team. The team should include people
with direct responsibility and knowledge of the particular
waste stream or area of the plant
Review data and inspect site. The assessment team
evaluates process data in advance of the inspection. The
inspection should follow the target process from the point
where raw materials enter the facility to the points where
products and wastes leave. The team should identify the
suspected sources of waste. This may include the produc-
tion process; maintenance operations; and storage areas for
raw materials, finished product, and work in progress. The
inspection may result in the formation of preliminary
conclusions about waste minimization 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 comprehensive 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, government
agencies, technical and trade reports, equipment 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 accomplished
through:
-------
Figure 1. The Waste Minimization Assessment Procedure
The Recognized Need to Minimize Waste
PLANNING AND ORGANIZATION
1 Get management commitment
• Set overall assessment program goals
> Organize assessment program task force
Assessment Organization &
Commitment to Proceed
ASSESSMENT PHASE
> Collect process and facility data
> Prioritize and select assessment targets
> Select people for assessment teams
> Review data and inspect site
> Generate options
1 Screen and select options for further study
Assessment Report of
Selected Options
FEASIBILITY ANALYSIS PHASE
> Technical evaluation
> Economic evaluation
• Select options for Implementation
Final Report, Including
Recommended Options
IMPLEMENTATION
• Justify projects and obtain funding
• Installation (equipment)
• Implementation (procedure)
Evaluate performance
Select New Assessment
Targets and Reevaluate
Previous Options
Repeat the Process
Successfully Implemented
Waste Minimization Projects
-------
• Good operating practices
• Technology changes
• Input material changes
• Product changes
Recycling includes:
• Use and reuse of waste
• Reclamation
Screenandselectoptionsforfurtherstudy.'nasscKeamg
process isintended to select the mostpromising options for
full technical and economic feasibility study. Through
either an infonnalrevieworaquantitativedecision-making
process,optionsthatappearmarginal,impracticaloririferior
are eliminated from consideration.
FEASIBILITY ANALYSIS
An option must be shown to be technically and eco-
nomically feasible in order to merit serious consideration
for adoption at a facility. A technical evaluation deter-
mines 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
productquality.Also.anynewproductsdevelopedthrough
process and/or raw material changes need to be tested for
market acceptance.
An economic evaluation is carried out using standard
measures of profitability, such aspaybackperiod.retum 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 economic costs. Sav-
ings and changes in revenue also need to be considered.
IMPLEMENTATION
An option that passes both technical and economic
feasibility reviews should then be implemented at a facil-
ity It is then up to the WMOA team, with management
support, to continue the process of tracking wastes and
identifying opportunities for wasteminimization, through-
outa facility and by way of periodic reassessments. Either
such ongoing reassessments or an initial investigation of
waste minimization opportunities can be conducted using
this manual.
References
Calif. DHS. 1987. Waste Audit Study: Paint
Manufacturing Industry. Report prepared by Jacobs
Engineering Group Inc., Pasadena, Calif., for the
CalifomiaDepartmentof HealthServices, Alternative
Technology Section, Toxic Substances Control
Division, April 1987.
ICF Consulting Associates, Jacobs Engineering Group,
and Versar. 1986. Guide to Solvent Waste Reduction
Alternatives. Prepared for California Department of
Health Services, Alternative Technology and Policy
Development Section, October 10,1986.
Pace Company Consultants and Engineers, Inc. 1983.
Solvent Recovery in the United States 1980-1990.
Houston, Texas.
USEPA. 1988. Waste Minimization Opportunity
Assessment Manual. Hazardous Waste Engineering
Research Laboratory, Cincinnati, Ohio, EPA/625/7-
88//003.
-------
SECTION 2
PAINT MANUFACTURING INDUSTRY PROFILE
Industry Description
As defined by Standardlndustrial Classification (SIC)
2851, the paints and allied products industry "comprises
establishments primarily engaged in the manufacture of
paints (in paste and ready mixed form), varnishes, lac-
quers, enamels and shellacs, putties, wood fillers and
sealers, paint and varnish removers, paint brush cleaners,
and allied paint products." Establishments engaged in
the manufacture of pigments (organic orinorganic), resins,
printing inks, adhesivesand sealants, or artist materials are
not included.
The industry is comprised of roughly 1375 establish-
ments nationwide. Approximately 44 percent of all paint
manufacturing plant sites are located in five states (Califor-
nia, New Jersey, New York, Illinois, and Ohio), with 67
percent being located in ten states. Most of the plants are
located near major population centers.
Products and Their Uses
Most small plants produce paint in 10 to 500 gallon
batches. Plants with more than 20 employees produce
paint in 200 to 3,000 gallon batches. Overall, the paint
industry sold 8.6 billion dollars worth of product in 1983
(S3.9 billion for architectural coatings, S3.0 billion for
product coatings, and S1.7 billion for special purpose
coatings) (Webber 1984). The amounts and distribution of
products manufactured by the paint industry in 1983 are
shown in Table 1.
For an average paint plant located in the U.S., 60
percent of its total annual production would be solvent-
based paint, 35 percent would be water-based paint, and 5
percent would be allied products. While a large percentage
of paint used for architectural coating is water-based
(more than 70 percent), solvent-based paint is still pre-
dominantly used for product and special purpose coatings.
Table 1.1983 Paint Products and Use
Distribution
Architectural Coatings
Product Coatings
Metal containers
Automotive
Machinery
Sheet, strip and coil
Metal furniture
Other
Special Purpose Coatings
High performance maintenance
Automotive and machinery
refinishing
Traffic paint
Other
463 million gallons
331 million gallons
19%
16%
6%
6%
5%
48%
130 million gallons
31%
29%
14%
26%
Source: Chemical and Engineering News (Webber 1984).
Raw Materials
Annual consumption rates: of raw materials used by
the paint manufacturing industry are shown for 1982 in
Table 2.
The majorraw materials used to manufacture paint are
resins, solvents, drying oils, pigments, and extenders.
Based on the wide variety of pziints produced, no one type
of material dominates the market.
Process Description
Detailed process flow diagrams of paint manufactur-
ing have been presented in the open literature (Haines
1954, Payne 1961). The following description briefly
highlights the production of the; industry's two main prod-
ucts: solvent-based paint and water-based paint At a
typical plant, both types of paint are produced. A block
flow diagram of the steps involved in manufacturing paint
is presented in Figure 2.
-------
Table 2. Raw Materials Used by the Paint Manufacturing Industry in 1982
Usage
Materials 1 844 minion |bs/yr.
Resins . 33<>/0
Alkyd J 19%
Acrylic igo/<(
Vinyl 29e/c
°*her 3774 million Ibs/yr.
Solvents 30o/0
Aromatic 27%
-Aliphatic 17%
Ketonss 12%
Alcohols u% ^ -
O*'101' 1062 million Ibs/yr.
Pigments 65%
Titanium dioxide 33%
Inorganic(a) 2%
°r9anic 11 62 million Ibs/yr.
Extenders 31o/0
Calcium carbonate 2g%
Talc 23%
Clay 21%
other 220 million Ibs/yr.
Miscellaneous 41%
Drying oils 18%
Plasticizers 41%
Other
SOUK*.: Chemical Economics Handbook(SRI1981)da«to,1977ad|Us«d.or1982prodU«™^ _
°
compounds.
ing sorn. of these-, resins.
-------
Figure 2. Block Flow Diagram for Paint Manufacture
Solvent Based
Resins
Pigments
Extenders
Solvents
Plasticizers
Tints
Thinner
Grinding
& Mixing
1-2-5-6
I
Grinding
2-5-6
1
J
Mixing
1-5-6
i
Filtering
4-5-6
I
Packaging
3-5-6
T
Final Product
Air Emissions of Volatile Organic Compounds
Process Waste Categories
1 Discarded Raw Material Containers
2 Baghouse Pigment Dusts
3 Off-Specification Paint
4 Filter Cartridges
5 Equipment Cleaning Wastes
Water Based
Water
Ammonia
*
^ Dispersant
Pigment
Extenders
. V
Resin
r^» Preservative
"* "* Antifoam
PVA Emulsion
Water
-------
Table3. Paint Manufacturing Process Wastes
Waste Description Process Origin
No
1.
Leftover raw materials
containers
2. Pigment dusts from air
3. Volatile organic compounds
4. Off-specification
5. Spills
6. Waste rinsewater
7. Waste solvent
8. Paint sludge
9. Filter cartridges
Unloading of materials
into mixing tanks
Unloading of pigment
Air emissions from storage
tanks and open processing
equipment.
Color matching(small
scale) production
Accidental discharge
Equipment cleaning using
water and/or caustic
solutions
Equipment cleaning using
solvent
Equipment cleaning sludges
removed from deaing
solution
Undispersed pigment
Composttlon RCRA Codas
Paper bags with a —
few ounces of left
over pigments
Pigments ~
Resins, soh/ant —
Paint
Paint
Paint
Paint, water,
caustic
Paint, solvent
Paint, water,
caustic, solvent
Paint
F002
F003
andequipmentcleaningwastes. Equipmentcleaningwastes
are a dominant waste stream.
The primary specific wastes associated with paint
manufacturing are listed in Table 3. Wastes generated by
the industry are usually managed in one of four ways: on-
site reuse, on-site recycling, off-site recycling, and off-site
treatment/disposal. On-site reuse involves the reuse of
waste (without treatment) as a feed or wash material for
producing other batches of paint Also included is the sale
or in-house use of off-specification paint as utility paint.
On-site recycling involves the reclaiming of solvent by
distillation or recovery of heating values by incineration.
Usually.on-siterecyclingisperformedbylargecompanies
(those that produce more than -35,000 gallons of solvent
waste each year) while small companies (those that pro-
duce 20,000 gallons or less per year) send the waste to an
off-site recycler. The fourth option, off-site treatment/
disposal involves incineration or land disposal.
References
Haines, H.W. (ed.) 1954. Resin and Paint Production -
1954 Style. Ind.Eng.Chem. 46(10):2010-22.
Payne, H.F. 1961. Organic Coating Technology.
2 volumes. John Wiley & Sons, New York, N.Y.
SRI. 1981. Chemical Economics Handbook, 1982.
Stanford Research Institute, Menlo Park, Calif.
Webber, D. 1984. Coating industry heading for record
year. Chem.Eng.News 61(40):51.
-------
SECTIONS
WASTE MINIMIZATION OPTIONS FOR PA1OT
MANUFACTURERS
Description of Techniques
This section discusses recommended waste minimi-
zation methods for paint manufacturers. These methods
come from accounts published in the open literature and
through industry contacts. The primary waste streams
associated with paint manufacturing are listed in Table 4
along with recommended control methods. In order of
occurrence at a facility, the waste streams are: equipment
cleaning wastes; spills and off spec paint; leftover inor-
ganic pigment in bags.and packages; pigment dust from
baghouses; filter cartridges; arid obsolete products/cus-
tomer returns.
The waste minimization methods listed in Table 4 can
be classified generally as source reduction, which can be
achieved through material substitution, process or equip-
ment modification, or better operating practices; or as
recycling. Anexampleofasourcereductionmethodinthe
table is the use of countercunent rinsing to reduce the
volume of cleaning waste, while an example of recycling
is the working of spilled product back into the process.
Table 4. Waste Minimization Methods for the Paint Manufacturing Industry
Waste Stream Waste Minimization Methods
Equipment cleaning wastes
(rinsewater, solvent and sludge)
Spills and off spec paint
Leftover inorganic pigment
in bags and packages
Air emissions, including pigment
dust
Filter cartridges
Obsolete products/customer returns
Use mechanical wipers on mix tanks.
Use high pressure wash systems.
Install Teflon liners on mix tanks.
Use foam/plastic pigs; to clean lines.
Reuse equipment claming wastes.
Schedule production to minimize need
for cleaning.
Clean equipment immediately.
Use countercurrent rinse methods.
Use alternative cleaning agents.
Increase spent rinse settling time.*
Use de-emulsifiers on spent rinses.111
Increase use of automation.
Use appropriate clean up methods.
Recycle back into process. Implement
better operating practices.
Use water soluble bags and liners.
Use recyclable/lined/dedicated
containers.
Modify bulk storage iianks.
Use paste pigments.
Install dedicated baghouse systems.
Improve pigment disj>ersion.
Use bag or metal mesh filters.
Blend into new products.
•"These methods can only be viewed as waste minimization if they allow the continued use of spent cleaning solutions.
-------
Better operating practices are procedural or institu-
tional policies that result in a reduction of waste. They
include:
• Waste stream segregation
• Personnel practices
- Management initiatives
- Employee training
- Employee-incentives
• Procedural measures
— Documentation
- Material handling and storage
— Material tracking and inventory control
- Scheduling
• Loss prevention practices
- SpUl prevention
- preventive maintenance
- Emergency preparedness
• Accounting practices
- Apportion waste management costs to
departments that generate the waste
Better operating practices apply to all waste streams.
Inaddition,specificbetteroperatingpracticesthatapplyto
certain waste streams are identified in the appropriate
sections that follow.
EQUIPMENT CLEANING WASTES
Equipment cleaning generates mostof the waste asso-
ciated with paintmanufacturing. Following production of
eithersolventorwater-basedpaints.considerable waste or
"clingage" remains affixed to the sides of the preparation
tanks. Thethreemeihodsof tankcleaningusedinthepaint
industry are solvent washing for solvent-based paint,
caustic washing for either solvent or water-based paint,
and water washing for water-based paint
Equipment usedforpreparation of solvent-basedpaint
isrinsed with solvent, which is then generally reused in the
following ways:
• Collectedandusedinthenextcompatiblebatch
of paint as part of the formulation.
• Collected and re-distilled either on or off-site.
• Collected and used with or without settling for
equipment cleaning, until spent. When the
solvent is finally spent, it is then drummed for
disposal.
In 1985, a survey conducted by the National Paint &
Coatings Association's Manufacturing Management
Committee showed that over 82% of the respondents
recycled all of their solvent waste either on-site or off-site.
With current costs of disposal, onsite distillation of solvent
can be economically justified for as little as eight gallons
of solvent waste generated per day. Of all the solvent that
is recycled, 75 percent is recovered with the-remaining
portion disposed of as sludge.
Caustic rinse is used for equipment cleaning of both
solvent and water-based paints, but more often with wa-
ter-based paints. Water rinsing is usually insufficient in
removing paint that has dried in the mix tanks. Since
solvent rinsing can usually remove solvent-based paint
that has dried, the need for caustic is less.
There are two major types of caustic systems com-
monly used by the paint industry. In one type of system,
caustic is maintained in a holding tank (usually heated) and
is pumped into the tank to be cleaned. The caustic drains
to a floor drain or sump from which it is returned to the
holding tank. In the second type of. system, a caustic
solution is prepared in the tank to be cleaned, and the tank
is soaked until it is clean. Most plants reuse the caustic
solution until it loses most of its cleaning ability. At that
time, the caustic is disposed of either as a solid waste or
wastewater with or without neutralization.
Water wash of equipment used in the production of
water-based paint is the source of considerable wastewater
volume, which is usually handled as follows:
• Collectedandusedinthenextcompatiblebatch
of paint as part of the formulation.
• Collected and used with or without treatment
for cleaning until spent
• Disposed with or without treatment as
wastewater or as a solid waste in drums.
Sludges from settling tanks are drummed and dis-
posed of as solid waste. Spent recycle rinsewater is
drummed and disposed of as solid waste after the soluble
content prohibits further use.
The percentageofsolvent-baseand water-base paints
produced is the most important factor that affects the
volume of process wastewater generated and discharged at
paint plants. Due to their greater use of water-wash, plants
producing 90 percent or more water-base paint discharge
more wastewater than plants producing 90 percent or more
solvent-base paint. Additional factors influencing the
amount of wastewater produced include the pressure of the
rinse water, spray head design, and the existence or ab-
sence of floor drains. Where no troughs or floor drains
exist, equipment is often cleaned externally by hand with
rags; when wastewater drains are present, there is a greater
tendency to use hoses. Several plants have closed their
floor drains to force the use of dry clean-up methods and
discourage excessive water use.
10
-------
Waste associated with equipment cleaning represents
the largest source of waste in a paint facility. Methods that
reduce the need or frequency of tank cleaning or allow fen-
reuse of the cleaning solutions are the, most effective.
Waste minimization methods considered include:
Use of mechanical devices suchas rubber wipers. In
order to reduce theamountofpaintleft clinging to the walls
of a mix tank, rubber wipers are used to scrape the sides of
the tank. This operation requires manual labor and hence
the percentage of waste reduction is a function of the
operator. Since the benefits will be offset by increased
labor, mechanization/automation should be considered.
Many new mixers are available that are designed with
automatic wall scrapers (Weismantel and Guggilam 1985).
These mixers can be used with any cylindrical mix tank
(flat or conical bottom).
Use of high pressure spray heads and limitihgwashl
rinse time. After scraping the tank walls, high pressure
spray hoses can be used in place of regular hoses to clean
water-based paint tanks. Based on studies (USEPA1979),
high pressure wash systems can reduce water use by 80 to
90 percent In addition, high pressure sprays can remove
partially dried-on paint so that the need for caustic is re-
duced. Tanks used for making solvent-based paints nor-
mally employ a built-in high pressure cleaning system. At
Lilly, in High Point, N.C., a high pressure cleaning system
was installed in several mix tanks. By continuously
pumping a fixed amount of solvent into a tank until it was
clean, the overall volume of solvent required for cleaning
was reduced (Kohlv Moses, and Triplett 1984).
Use of Teflon* lined tanks to reduce adhesion and
improve drainage. The reduced amount of "clingage" will
make dry cleaning more attractive. This method is proba-
bly applicable only to small batch tanks amenable to
manual cleaning.
Use^ofa plastic or foam "pig" to clean pipes. It was
reported that much of the industry is currently using plastic
or foam "pigs" (slugs) to clean paint from pipes. The "pig"
is forced through the pipe from the mixing tank to the
filling machine hopper. The "pig" pushes ahead paint left
clinging to the walls of the pipe. This, in turn, increases
yield and reduces the subsequent degree of pipe cleaning
required. Inert gas is used to propel the "pig" and minimize
drying of paint inside the pipe. The equipment (launcher
and catcher) must be carefully designed so as to prevent
spills, sprays, and potential injuries, and the piping runs
must be free of obstructions so that the "pig" does not
become stuck or lost in the system.
Better operating practices. At Desoto, in Greens-
boro, N.C., wash solvent from each solvent-based paint
batch is separately collected and stored. When the same
type of paint is going to be pioduced, waste solvent from
the previous batch is used in place of virgin solvent In
1981, Desoto produced 25,000 gallons of waste mineral
spirits. In 1982, when the system was implemented, waste
solvent production amounted to 400 gallons. This same
technique is currently being applied to their latex paint
production operation (Kohl, Moses and Triplett 1984).
Insomecases,cleaningsludgKcanberecycled. One of the
audited facilities discussed in the DHS report (Calif. DHS
1987) recycles the sludge from alkaline cleaning of their
water-based paint mix tanks into a marketable product,
Other waste minimization measures based on good oper-
ating practices would be to schedule paint production for
long runs or to cycle from light to dark colors so that the
need for equipment cleaning would be reduced. For
facilities using small portable mix tanks for water-based
paints, immediate cleaning after use would reduce the
amount of paint drying in the tank and hence reduce the
need for caustic. Many times, dirty equipment is sent to a
central cleaning operation where it waits until a given shift
(usually night) to be cleaned;. While tanks wait to be
cleaned, the residual paint dries up, often necessitating the
use of caustic solution for cleaning. By designing and
operating the cleaning operation to handle any peak load
continuously, all need for caustic should be eliminated or
drastically reduced.
For plants employing CIP (cleari-in-place) and recycle
systems for wash/rinse operations, the inventory replace-
ment frequency and waste volume can be minimized by
using these following waste reduction methods:
A counter current rinsing sequence. For facilities that
have additional storage spaces available, countercurrent
rinsing can be employed. This technique uses recycled
"dirty" solution to initially clejin the tank. Following this
step, recycled "clean" solution is used to rinse the "dirty"
solution from the tank. Since the level of contamination
builds up more slowly in the recycled "clean" solution than
with asimplereuse system, solution life is greatly increased.
Countercurrent rinsing is more common with CIP systems,
but can be used with all systems.
Alternative cleaning agent. Many facilities use
caustic to clean their mixing equipment. When the build-
up of solids and dissolved organics reaches a given con-
centration, the cleaning efficiency decreases and the solution
must be replaced. As reported by one of the audited
facilities, substituting a proprietary alkaline cleaning so-
lution for their caustic solution cut the solution replacement
frequency in half and thereby reduced the volume of
cleaning solution requiring disposal.
^Registered trademark ofEJ. Du Pont de Nemours & Co.
11
-------
Sludge dewatering by filtration or centrifugation.
Theabovethreemethods areuseful inreducing theamount
of waste entering the environment provided they allow the
continued useofthecleaningsolution.Dewatering only to
reduce sludge disposal volumes should not be viewed as
waste minimization.
Provision for adequate solid settling time in spent
rinse solution.
Use of de-emulsificrs in rinse water to promote
emulsion breakdown and organic phase separation.
OFF-SPECIFICATION PAINT
Most off-specification paint is produced by small
shops that deal in specialty paints. Since these paints cost
more to produce, and therefore sell at a premium price,
most off-spec paint is reworked into a salable product
Since elimination of off-spec paint production has built-
in economic incentives.thefollowing techniques are widely
used:
Increased automation.
Better operating practices. Unless the sludge from
wetcleanup can be recycled into amarketable product, the
useof dry cleanupmethodsshouldbemaximized wherever
possible. By closing floor drains and discouraging em-
ployees from routinely (i.e. needlessly) washing down
areas, some facilities have been able to achieve a large
decrease in wastewater volume (USEPA 1979). Other
effective ways to reduce water use include employing
volume-limiting hose nozzles, using recycled water for
cleanups, and actively involved supervision.
BAGS AND PACKAGES
Inorganic pigments, which may contain heavy metals
and therefore be classified as hazardous, are usually
shipped in 50 pound bags. After emptying the bag, an
ounce or two of pigment usually remains inside. Empty
containersofliquidrawmaterialsthatconstiiute hazardous
waste (e.g. solvents and resins) are typically cleaned or
recycled to the original raw material manufacturer or to a
local drum recycler. Empty liquid containers are excluded
from the following discussion. Thefollowingwastereduc-
tion techniques for bags and packages were noted:
Use of water soluble bags for toxic pigments and
compounds used in water-based paints. When empty, the
bags could be dissolved or mixed in with the paint. Such
a method is commonly used for handling mercury com-
pounds and other paint fungicides. This method could not
be used, however, when producing high quality, smooth
finish paint since the presence of this material could affect
the paint's film forming property or could increase the load
on the filters which would increase filter waste.
*
Use ofrinseablelrecyclable drums withplastic liners
instead of paper bags.
Better operating practices. Through industry contacts, it
was established that the most effective way of reducing
hazardouswasteassociated with bagsand packages (orany
otherwastestream)was to segregate Unhazardous materials
from the non-hazardous materials. As an example, empty
packages that contained hazardous materials should be
placed into plastic bags (so as to reduce or eliminate
dusting leading to non-hazardous material contamination)
and should be stored in a special container to await col-
lection.
AIR EMISSIONS _ v • "
The two major types of air emissions that occur in the
paint manufacturing process are volatile organic com-
pounds and pigment dusts. Volatile organics may be
emitted from the bulk storage of resins and solvents and
from their use in open processing equipment such as mix
tanks. Since most existing equipment is of open design,
reducing or controlling organic emissions from process
equipment could require substantial expenditures in retro-
fitcosts. Additional work on control methods appears to be
warranted in this area, and as a result, the following
measures only address bulk storage and pigment handling.
Controlbulkstorage air emissions. Many methodsare
available for reducing the amount of emissions resulting
from fixed roof storage tanks. Some of these methods
include use of conservation vents, conversion to floating
roof, use of nitrogen blanketing to suppress emissions and
reduce material oxidation, use of refrigerated condensers,
use of lean-oil or carbon absorbers, or use of vapor com-
pressors. When dealing with volatile materials, employ-
ment of one or more of these methods can result in cost
savings to the facility by reducing raw material losses.
Some of the dusts generated during the handling,
grinding, and mixing of pigments can be hazardous.
Therefore, dust collection equipment (hoods, exhaust fans,
and baghouses) are provided to minimizea worker's expo-
sure to localized dusting and to filter ventilation air ex-
haust. The waste reduction methods considered consist of:
Use of pigments in paste form instead of dry powders.
Pigments in paste form are dry pigments that have been
wetted or mixed with resins. Since these pigments are wet,
less dust or no dust is generated when the package is
opened. In addition, most pigments in paste form are
supplied in drums (which can be recycled) and therefore
would eliminate the waste due to empty bags. While this
method would increase the amount of pigment handling
occurring at the supplier's facility, it can be argued that the
overall number of handling/transfer points for dry powder
will be greatly reduced along with the probability of spills
and dust generation.
12
-------
Dedicatedbaghouse systemfor pigment loading area.
At Daly-Herring Co., in Kinston, N.C., (while Daly-
Hening is engaged in the formulation of pesticides and not
paints, there are many material handling problems common
to both industries) dust streams from several different
production areas were handled byasingle baghouse. Since
all of the streams were mixed, none of the waste could be
recycled to the process that generated them. By installing
separate dedicated baghouses for each production line, all
of the collected pesticide dust could be recycled (Huisingh
and Martin 1985). While this example is not intended to
imply that most of the dust generated by the paint industry
could be recycled, it does show the overall importance of
keeping waste streams segregated.
SPILLS
Spills are due to accidental or inadvertent discharges
usually occurring during transfer operations or equipment
failures (leaks). Spilled paint and the resulting clean up
wastes are usually discharged to the wastewater treatment
system or are directly drummed for disposal. If the plant
has floor drains, large quantities of water may be used to
clean up water-based paint spills. Dry cleaning methods
are employed for cleaning of solvent-containing spills or
for water-based spills where floor drains are not available.
Wastereduction methods similar to those foroff-spec paint
include:
Increased automation.
Better operating practices. Unless the sludge from
wet cleanup can be recycled into a marketable product, the
use of dry cleanup methods should be maximized wherever
possible. By closing floor drains and discouraging em-
ployees from routinely (i.e. needlessly) washing down
areas, some facilities have been able to achieve a large
decrease in wastewater volume (USEPA 1979). Other
effective ways to reduce water use include employing
volume-limiting hose nozzles, using recycled water for
cleanups, and actively involved supervision.
FILTER CARTRIDGES
Spent filter cartridges are produced during the paint load-
ing operation. These cartridges are designed to remove
undispersed pigment from the paint during loading and are
saturated with paint when removed. Hence, waste minimi-
zation and economy both call for as small a cartridge as
possible so as to reduce the amount of paint lost and the
capital spent for the filters. If frequent filter plugging is a
problem, then it should be first addressed from the stand-
point of improving pigment dispersion, and not from the
standpoint of increasing filter area.
Viable alternatives to cartridge filters include bag filters
and metal mesh filters. Metal mesh filters are available in
very fine micron sizes and they can be cleaned and reused.
Since itis very important to minimize all wastes, the issue
of mesh filter cleaning waste reuse or recyling would need
to be addressed before switching to these filters.
OBSOLETE PRODUCTS/CUSTOMER RETURNS
Obsolete products and customer returns can be blended
into new batches of paint Obsolete products result from
changes in customer demand, mew superior products, and
expired shelf life. Marketing policies, such as discounting
older paints, can reduce the amount of obsolete products
requiring disposal.
References
Huisingh, D. and L. Martin. 1985. Proven Profit from
Pollution Prevention. Conference draft. The Institute
for Local Self-Reliance, Washington, D.C.
Kohl, J., P. Moses, and B. Triplet!. 1984. Managing and
Recycling Solvents. North Carolina Practices,
Facilities, and Regulations. Raleigh, N.C.; North
Carolina State University.
USEPA 1979. U. S. Environmental Protection Agency,
OfficeofWaterandWasteManagement Development
• document for proposed effluent limitation guidelines,
new source performance:5tandards,andpretreatment
standards for the paint formulating point source
category. EPA-440-l-79-049b. Washington, D.C.:
U.S. Environmental Protection Agency.
Weismantel,G.,and S.Guggilam. 1984. Mixing and size
reduction (A chemical engineering special advertising
section). Chem.Eng. 92(13): 71-109.
13
-------
SECTION 4
GUIDELINES FOR USING THE
WASTE MINIMIZATION ASSESSMENT WORKSHEETS
Waste minimization assessments were conducted at Conducting Your Own Assessment
severalpaintmanufacturingplantsintheLos Angelesarea. ^ worksheets provided in this section are intended
Hie assessments were used to develop the waste minimi- to g^ p^ manufacturers in systematically evaluating
zation questionnaire and worksheets that are provided in waste generating processes and in identifying waste mim-
the following section. mizationopportunities. These worksheets include only the
assessment phase of the procedure described in the w aste
A comprehensive waste minimization assessment Minimization(>)pOrtunity Assessment Manual. Forafull
iMludesaplaraungandorganizationalstep,anassessment -^^^^^.^mi^onassessmentprocedures,
step thatincludes gathering background data and informa- £ &•&* ^^
tion, a feasibility study on specific waste minimization
options.andanimplementationphase. Table 5 lists the worksheets that are provided in this
section.
14
-------
Table 5. List of Waste Minimization Assessment Worksheets
Number Title Description
i.
2A.
2B.
2C.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Waste Sources
Waste Minimization:
Material Handling
Waste Minimization:
Material Handling
Waste Minimization:
Material Handling
Option Generation:
Material Handling
Waste Minimization:
Material Substitution/
Primary Dispersion
Techniques
Option Generation:
Material Substitution/
Primary Dispersion
Techniques
Waste Minimization:
Process Modification
(Let-Down)
Option Generation:
Let-Down Techniques
Waste Minimization:
Process Modification
(Filtering and Filling)
Option Generation:
Filtering and Filling
Waste Minimization:
Good Operating Practices
Option Generation:
Good Operating Practices
Waste Minimization:
Reuse and Recovery
Typical wastes generated at
paint manufacturing plants.
Questionnaire on general
handling techniques for raw
material handling.
Questionnaire on procedures used '
for bulk liquid handling.
Questionnaire on procedures used
for handling drums, containers
and packages.
Waste minimization options for
material handling operations,,
Questionnaire on material
substitution and primary dispersion
operations.
Waste minimization options for
material substitution and mollification
of the primary dispersion opera-
tions.
Questionnaire on let-down
procedures.
Waste minimization opportunities
for let-down techniques.
Questionnaire on filtering,
filling, and on-site tank
cleaning procedures.
Filtering and filling waste
minimization options.
Questionnaire on use of good
operating practices.
Waste minimization options for
good operating practices.
Questionnaire on opportunities
for reuse and recovery of wastes.
15
-------
Waste Minimization Assessment
Prepared By
Checked By
Sheet of • Page of
WASTE SOURCES
Significance at Plant
Wast* Source: Material Handling
Ott'Spec mcterlals
Obsolete raw materials
Obsolete products
Spills I leaks (liquids)
Spills (powders)
Empty container cleaning
Container disposal (metal)
Container disposal (paper)
Pipeline/tank drainage
Laboratory wastes
Evaporative losses
Wast* Source: Process Operations
Mill cleaning
Portable tank cleaning
Container cleaning
Stationary tank cleaning
Mixer cleaning
FUter equipment cleaning
Spent filter elements
Filling equipment cleaning
Baghouae fines
Other
16
-------
Firm.
Site
Date
Wast* Minimization Assossment
Proj. No.
WORKSHEET
2A
WASTE MINIMIZATION:
Material Handling
Prepared By
Checksci By
Sheet of ; Page of
A. GENERAL HANDLING TECHNIQUES
Are all raw materials tested for quality before being accepted from suppliers?
Describe safeguards to prevent the use of materials that may generate off-spec product:.
Dyes
Dno
Is obsolete raw material returned to the supplier?
Is inventory used in first-in first-out order?
Is the inventory system computerized?
Does the current inventory control system adequately prevent waste generation?
What information does the system track?.
Dyes
Dyes
Dyes
Dyes
Dno
Dno
Dno
Dno
Is there a formal personnel training program on raw material handling, spin prevention. D yes D no
proper storage techniques, and waste handling procedures?
Does the program include information on the safe handling of the types of drums, containers D yes D no
and packages received?
How often is training given and by whom? ——, , —
17
-------
WORKSHEET
WASTE MINIMIZATION:
Material Handling
B. BULK LIQUIDS HANDLING
What safeguards am in pJact to prevent spills and avoid ground contamination during the filling of storage tanks?
High toval shutdown/alarms D Secondary containment D
Flow totalizers with cutoff D Other
Describe the system:.
Are alf emissions from solvent storage tanks controlled by means of:
Conservation vents
Nitrogen blanketing
Absorber/Condenser
Other vapor toss control system
Describe the system: • —— —
Dyes
Dyes
Dyes
Dyes
Dno
Dno
Dno
Dno
Are all storage tanks routinely monitored for leaks?
Describe procedure and monitoring frequency for above-ground/vaulted tanks:.
Dyes
Dno
Underground tanks:.
How are tha liquids in these tanks dispensed to the users? (i.e., in small containers or hard piped.).
What measures are employed to prevent the spillago of liquids being dispensed?.
When a spUl 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):.
18
-------
Firm ,
Site .
Date
Wast* Minimization Assessment
Prej. No.
Prepared By
By
Sheet __ of _ Page _ of
WORKSHEET
2C
WASTE MINIMIZATION:
Material Handling
C. DRUMS, CONTAINERS, AND PACKAGES
Are drums, packages, and containers inspected for damage before being accepted? G yes
Are employees trained in ways to safety handle the types of drums & packages received? G yes
Are they property trained in handling of spiffed raw materials? G yes
Are stored items protected from damage, contamination, or exposure to rain, snow, sun & heat? G yes
Describe handling procedures for damaged items:.
G yes
Does the layout of the facility result in heavy traffic through the raw material storage area?
(Heavy traffic increases the potential for contaniinating raw materials with dirt or dust and
for causing spilled materials to become dispersed throughout the facility.) G yes
Can traffic through the storage area be reduced?
To reduce the generation of empty bags & packages, dust from dry material handling and liquid
wastes due to cleaning of empty raw material drums and/or customer returns','
has the facility attempted to:
Use pigments in slurry/paste form? G yes
Purchase hazardous materials in preweighed containers to avoid the need for weighing? G yes
Purchase preweighed hazardous materials in water or solvent soluble bags? G yes
Use reuseable/recyclable drums with liners instead of paper bags? G yes
Use larger containers or bulk delivery systems that can be returned to supplier for cleaning? G yes
Dedicate baghouse systems in the pigment loading area so as to segregate hazardous
from non-hazardous dusts? G yes
Reformulate the ctearang waste Into a product? G yes
Discuss the results of these attempts!.
Gno
Gno
Gno
Gno
Gno
Gno
Gno
Gno
Gno
Gno
Gno
Gno
Gno
Are all empty bags, packages, and containers that contained hazardous materials segregated
from those that contained non-hazardous wastes? •.,...., .:......, G yes Gno
Describe method currentty used to dispose of this waste: _ .——
19
-------
WORKSHEET
Wast* Minimization Assessment
Proc. Unit/Qper •
Prej. No.
OPTION GENERATION:
Material Handling
Prepared By .
ChsckedBy .
Sheet. of
Page of
.^
Meeting Format (*.g., bralnstormlng, nominal group technique).
Meeting Coordinator
MMtlng Participants.
Ratlonale/Nomairks on Option
Suggested wast* Minimization Options
General Handling T*chnlqu*s
Quality Control Check
Return Obsolete Material To Supplier
Minimize Inventory
Computerize Inventory
Formal Training
B. Bulk Liquids Handling
High Level Shutdown/Alarm
Ftow Totalizers with Cutotl
„.
Secondary Containment
m~^—— •.^•^•1^—•-••
Air Emission Control
Leak Monitoring
Spilled Material Reuse
Cleanup Methods to Promote Recycling
Drums, Containers, and Packages
Raw Material Inspection
Proper Storage/Handling
Slurry/Paste Pigments
Preweighed Containers
Soluble Bags
Reusable Drum
Buk Delivery
Dedicated Baghouses
Waste Segregation
Reformulate Cleaning Waste
20
-------
rtrm .
Site ,
Data.
Waste Minimization Assessment
Proj. No.
Prepared By
Checked By
Sheet of _ Page _ of
WORKSHEET
WASTE MINIMIZATION:
Material Substitution
Primary Dispersion Techniques
A. MATERIAL SUBSTITUTION
Do any Of the paints or coatings produced contain hazardous materials (i.e., chlorinated
solvents, lead or chrome pigments, mercury, etc.)?
If yes, has material substitution been tried?
Discuss the results:—\ . —
Dyes
Dyes
B. PRIMARY DISPERSION (skip this section H mills not used)
Are separate containers used for feeding and receiving materials passed through the mill? G yes
Are multiple passes of the material through the mill often required? D yes
Can the number of containers used (requiring cleaning) be reduced by continuously
recirculating the material through the mill instead of using multiple passes? D yes
Would the purchase of a more efficient mill eliminate the need tor multiple passes? D yes
Is dispersed material used immediately for let-down? Dyes
If sent to storage, does the material often require redteperston? D yes
Would reducing the amount of material sent to intermediate storage reduce the use of the mill
and the subsequent need for cleaning? D yes
Discuss:.
Is solvent used for cleaning the mills?
Can the cleaning waste be used as part of the formulation during let-down?
As part of another formulation or for other cleaning activities?
Can the type of cleaning agent be standardized so as to promote reuse or recycling?
. Discuss:____ .—: —
Dyes
3 yes
Dyes
Dyes
Dno
Dno
Dno
Dno
Dno
Dno
Dno
Dno
Dno
Dno
Dno
Dno
Dno
21
-------
Wast* Minimization Assessment
Prepared By
Checked By
Sheet _._ of __ Page of
OPTION GENERATION:
WORKSHEET
Material Substitution
Primary Dispersion Techniques
Meeting format (e.g., bralnstormlng, nominal group technique]
Meeting Coordinator
Meeting Participants
Rationale/Remarks on Option
Suggested Waste Minimization Options
A. Substitution/Reformulation Techniques
Pigment Substitution
Solvent Substitution
Product Reformulation
Other Raw Material Substitution
e. Primary Dispersion Techniques
Recirculatton Through Mill
Improve Production Planning
Clean with Part of Batch
Standardize Cleaning Solvent
22
-------
Prepared By
Checked By
Waste Minimization Assessment
Sheet of Page __ of —
WORKSHEET
WASTE MINIMIZATION:
Process Modification
LET-DOWN TANKS
Is the piping to and from the let-down tanks routinely flushed with water or solvent?
Is the piping -pigged' before flushing?
Dyes
Gyes
Gno
Gno
Describe how waste from flushing is handled:.
Describe the cleaning sequence (i.e.. manually scraped, washed with a high-pressure spray system using caust.c.
then solvent rinsed) used for cleaning portable let-down tanks:— :
Describe the cleaning sequence used for cleaning fixed let-down tanks:.
Describe the cleaning sequence used for cleaning the mixing units:
How are cleaning wastes handled and disposed of?.
Much more drastic cleaning measures are usually required when the paint is allowed to dry
inside the tank. Are all of the tanks cleaned promptly after use? Gyes
Are any precautions taken during this flme to prevent the paintfrem drying? Gyes
Describe: — —'
Are there established procedures for communications between cleaning & production crew?
For situations where the paint does dry in the tank. \a your spray cleaning system effective?
Has the use of new nozzle heads or higher pump pressures been attempted?
K a high-pressure spray system is not used for cleaning tanks, am there plans to install one?
if caustic is used, have alternative commercial cleaning solutions been tried?
Results: _ ——
Gyes
Gyes
Gyes
Gyes
Gyes
Can batches be sequences from light-to-dark to reduce cleaning needs?
Has the facility investigated the effect of reduced cleaning on product quality?
Was the testing performed on a lab scale or in production?
Results:
Gyes
ayes
G yes
Gno
Gno
Gno
Gno
Gno
Gno
Gno
Gno
Gno
Gno
23
-------
waste Minimization Assessment
Proc. Unit/Oper.
PTOJ.NO.
Prepared By
Checked By
Sheet of Page •
OPTION GENERATION:
Let-Down Techniques
MMtlng format («.Q., bralnstormlng, nominal group technique)
MMtlng Coordinator
MMtlng Participants
Rationale/Remarks on Option
Suggtstad Waste Minimization Opttona
Ltt-Down Tachnlquaa
Mechanical Cleaning
Clean Promptly
Proper Communications
Prevent Paint Drying
High Pressure Spray Cleaning
Use of Efficient Nozzles
Replace Caustic Solution
LighHQ-Dark Sequence
Avoid Unnecessary Cleaning
__———— —
Dedicate Tanks
Standardize Cleaning Solvent
Reuse/Rework Solvent Waste
Waste Segregation
M™^™^™™^^"^"""^™""^•••••""•^
Ensure Proper Batching
Minimize Evaporative Loss
24
-------
Firm
Site
Wast* Minimization Assessment
Proj. No.
Prepared By '
GhecksidBy
Sheet of Page of
WORKSHEET
8
WASTE MINIMIZATION:
Process Modification
FILTERING & FILLING
Are any of the fitter units dedicated to a particular product fine?
Would increased dedication reduce the need for fitter replacement or cleaning?
Has the facility attempted to replace disposable cartridge fitters with reusable fitters such as
bags or metal mesh?
What type of reusable fitter was tried and what were the results:-
Dyes
D yes
Gyes
Dno
Dno
Dno
How are the wastes from spent fitter cartridges or reusable filter cleaning handled?.
Are any of the fining units dedicated to a particular product fine?
Would increased dedication reduce the need for cleaning?
Describe the filling unit cleaning procedures and how cleaning wastes are handled.
Dyes
ID yes
Dno
Dno
25
-------
•Inn
Site
Data,
Waste Minimization Assessment
Proc. Unit/Oper
Proj. No
Prepared By
ChecksdBy
Sheet __ of Page of
WORKSHEET
9
OPTION GENERATION:
Filtering & Riling
MMtlng'fonnat (e.g., bralnstormlng, nominal group technlque).
Meetlng Coordinator ——
MMtlng Participants —. —
Suggested Waste Minimization Options
Currently
DoneY/N?
Rationale/Remarks on Option
Filtering Jk Riling Techniques
Dedicate Fitter Units
Use Wire Screen Fitters
Use Bags, Not Cartridges
Reuse Filter Bags
Dedicate Filling Units
Ught-to-Dark Sequence
26
-------
(___ wast* Minimization Assessment
•m
Date Proj. No '. — s
WPRKSHEET WASTE MINIMIZATION:
10 Good Operating Practices
Prepared By
Shaekad By
£heet of Page of
A. PRODUCTION SCHEDULING TECHNIQUES
Is the production schedule varied to decrease wast* generation? (For example, do you
attempt to increase size of production nms and minimize cleaning by accumulating orders or
production for inventory?) -Dyes Gno
[Joes tfw production include lignt-to-daric manufacturing sequence?
Dyes Gno
Are there any other attempts at eliminating cleanup steps betwesn subsequent batches? D yes Gno
- . . • •
B. AVOIDING OFF-SPEC PRODUCTS
Is the batch fprmuiatton attempted in ma lab before larg* scale production?
C. GOOD OPERATING PRACTICES
Are plant material balances routinely performed?
Are they performed tor each material of concern (e.g. solvent) soparatety?
Are records kept of individual wastes with their sources of origin and eventual dte
' (This can aid in pinpointing large waste streams and focus reuse efforts.)
Are the operators provided win detailed operating manuals or msirucuon seis f
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?
n yes D no
D yes G no
Dyes Gno
posall? ' O yes • G no
Dyes.. Gno
Dyes Gno
. ; Dyes Gno'
Dyes Gno
! Dyes Gno
Dyes Gno
Has a waste minimization assessment been performed at the facility in the past?
Dyes Gno
• " • •
27
-------
Waste Minimization Assessment Prepared By
e«jfft pmr. LJntVOpfir - . Checked By __
_ . »,.. Sheet of Page of
WORKSHEET OPTION GENERATION:
11 Good Operating Practices
Meeting format (e.g., bralnstormlng, nominal group technique)
Suggested Waste Minimization Options
A. Production Scheduling Techniques
Increase Size of Production Run
Ught-to-Daik Sequence
Avoid Unnecessary Cleaning
B. Avoiding Off-Spec Products
Test Batch Formulation in Lab
a Good Operating Practices
Perform Material Balances
Keep Records of Waste Sources & Disposition
Waste/Materials Documentation
Provide Operating Manuals/Instructions
Employee Training
Increased Supervision
Provide Employee Incentives
Encourage Dry Cleanup
Increase Plant Sanitation
Establish Waste Minimization Policy
Set Goals for Source Reduction
Set Goals for Recycling
Conduct Annual Assessments
Currently
Done Y/N?
Rationale/Remarks on Option
28
-------
t~m Wast* Minimization Assessment
.«»• .
nata Pmj Nfl. •
' •
WORKSHEET WASTE MINIMIZATION:
1 2 Reuse and Recovery
Preoared By
Chiiekad By
Sheet of Page of
A. SEGREGATION
Segregation of wastes reduces the amount of unknown material in waste and improves
prospects for reuse & recovery.
Are different solvent wastes due to equipment clean-up segregated? G yes Gno
Are aqueous wastes from equipment clean-up segregated from solvent wastes? Dyes Gno
Are spent alkaline solutions segregated from the rinse water streams? 3 yes Dno
If no. exDlain:
B. ON-SITE RECOVERY
On-site recovery of solvents by distillation is economically feasible for as little as 8 gallons .
of solvent waste per day.
Has on-site distillation of the spent solvent ever been attempted? CD yes G no
If yes, is distillation still being performed? Dyes Dno
C. CONSOLIDATION/REUSE
Are many different solvents are used for cleaning? 3 yes G no
If too many small-volume solvent waste streams are generated to justify on-site distillation,
can the solvent used for equipment cleaning be standardized? G yes D no
is spent cleaning solvent reused? G yes Gno
Are mere any attempts at making the rinse solvent part of a batch formulation (rework)? G yes Gno
Are any attempts made to blend various waste streams to produce marketable products? G yes G no
Are spills collected and reworked? G yes Gno
Describe which measures were successful and far which typ«* «f paint!
n VBS 1 no
Is your solvent waste segregated from other wastes? G yes Gno
Has off-site reuse of wastes through Waste Exchange services been considered? G yes G no
Or rouse through commercial brokerage firms?
29
-------
APPENDIX A
CASE STUDIES OF PAINT MANUFACTURING PLANTS
In 1986 the California Department of Health Services
commissioned a waste minimization study (DHS 1987) of
two paint manufacturing firms, called Plants A and B in
this guide. The results of the two waste assessments were
used to prepare waste minimization assessment work-
sheets to be completed by other paint manufacturers in a
self-audit process. The worksheets were sent to a third
paintmanufacturer.totesttheireffectivenessinguidingan
assessment
The paint manufacturing plants were chosen for their
willingness toparticipate in the study, their applicability to
the study's objectives, and the potential usefulness of the
resulting data to the industry as a whole. Plant A produces
water-based architectural coatings and Plant B produces
solvent-basedindustrialcoatings. Thewasteminimization
assessments were concerned with waste generated within
theplant boundaries and not with waste derived from paint
application or disposal of painted parts or stripped paint
This Appendix section presents the results of the
assessments of Plants A and B and potentially useful
waste minimization options identified through the assess-
ments. Also included are the practices already in use at the
plant that have successfully reduced waste generation from
past levels.
The waste minimization assessments were conducted
according to the description of such assessments found in
the "Introduction: Overview of Waste Minimization," in
this guide. The steps involved in the assessments were (see
also Figure 1):
• Planning and organization
• Assessment phase
• Feasibility analysis phase
The fourth phase, Implementation, was not a part of
these assessments since they were conducted by an outside
consulting firm. It was left to the paint manufacturers
themselves to take steps to implement the waste minimiza-
tion opyions that passed the feasibility analysis.
30
-------
PLANT A WASTE MINIMIZATION ASSESSMENT
Planning and Organization
Planning and organization of the assessment was done
by the consulting firm with the assistance of personnel
from the paint manufacturing firm. Initial contact was
made with the paint manufacturer's plant operations man-
ager, a high level manager who could provide the com-
pany's commitment to cooperate in the assessment and
provide all the necessary facility and process information.
The goal of this joint effort was to conduct a comprehen-
sive waste minimization assessment for the plant Under
different circumstances, in a company with its own on-
going waste minimization program, goals could be set to
target a specific amount or type of waste to be reduced; or
to conduct a waste minimization assessment each year, or
other goal. The waste assessment task force in the case of
Plant A consisted of the consultants working together
with the plant manager. This task force also functioned as
the assessment team.
Assessment Phase: Process and Facility
Data
Initial discussions by telephone between the consult-
ants and the plant manager were used to request process
and facility information prior to a site visit These discus-
sions also served to identify particular waste streams of
concern to plant managers — in particular, the disposal of
cartridge filters.
1 At the .site visit, the plant operations manager and
consultants met to review the facility's operations and its
potential target waste streams. The manager conducted a
facility tour and introduced the consultants to process
managers and workers involved in materials and waste
handling. Someofthesepeople were interviewed toobtain
information about specific procedures used at the plant
FACILITY DESCRIPTION
Plant A produces a wide variety of architectural coat-
ings: 76 lines of paint products and eight lines of aerosol
spray paints for distribution through retail outlets, and 55
lines of aerosol and specialty paints for sale through
distributors. About SOpercentof the paints producedat this
facility are water-based and the remainder are solvent-
based. The water-based coatings are latexes and the
solvent-based coatings are m ostly alkyd resins dissolved in
solvents. Figure A-l presents the annual production rates
of paints since 1982. Most of the paints produced are for
use by the general public.
1 .
7 .
1 .
Production •
fWthi
Millkmocf
Giltoiw 4 '
1 .
I .
i .
o .
7.2W
1882
•.407
Vh9
1M3 1M4 1985
Vwr
Fig. A-l. Annual Production Rates of Paints at Plant A since
1982
RAW MATERIALS MANAGEMENT
The raw materials used at Plant A include resin solu-
tions, emulsions, solvents, pigments, bactericides, fungi-
cides, and extenders. Some defoamers and surfactants are
also added to the water-basal batches. Table A-l lists the
principal raw materials used by the plant in 198S.
The solvents used at mis facility include aliphatics,
aromatics, ketones, or glycol ethers. Glycols such as
diethylene glycol, propylene glycol, or Texanol are added
to the water-based formulations to increase the paint
drying time and to act as an ami-freeze. The solvents are
31
-------
lather delivered and stored in drums or delivered in bulk
and held in the above-ground diked storage tanks.
The pigments are delivered in bags when used in
powderform,andindrumsorinbulkwhenusedinslurried
form. The use-of slurried pigments is predominant in
water-based formulations. Some solvent-based formula-
tions use pigments in paste form, which are purchased in
five gallon containers.
A complete inventory check is done four times a year,
though limited inventory checks are done on a daily basis.
Plant A is planning to convert from a manual to a compu-
terized inventory system.
Table A-l. Raw Materials Used at Plant A
Description
Solvents
Resins
Pigments
Extenders
Miscellaneous Additives
Material
Aliphatics
Aromaiics
Ketones
Alcohols
Diethylene glycol
Propylene glycol
Acrylics
Vinyl-acrylics
Alkyds
Titanium dioxide
Organic pigments
Red oxide
Yellow oxide
Other inorganic pigments
Calcium carbonate
Clay
Talc
Silicates
Bactericides and fungicides
Surfactants and defoamers
Viscosity modifiers
Ammonia
Others
PROCESS DESCRIPTION
The production of paints at Plant A is shown in block
flow diagrams in Figures A-2 through A-7. The descrip-
tion is general enough to apply to the production of both
solvent- and water-based paints in most cases.
The first step in paint production is the dispersion of
the pigments (see Figure A-2). The pigments in emulsion
or slurry form, along with the solvents, resins, and addi-
tives are added directly to a mill in the primary dispersion
step. The dispersed material from the mill is then pumped
directly to the let-down tanks. In less than five percent of
the cases, the pigments (in emulsion, slurry, or dry form)
areaddedtootherrawmaterialsinaportabletankorasmall
container. The contents of the tank or container are then
dispersed in a sand mill, ball mill, or high-speed mill and
either collected in another portable tank or directly added
to the let-down tank. In all cases, the portable tanks or
containers are reused several times without any cleaning
but are ultimately sent for cleaning.
The dispersion mills are dedicated to aparticular type
The dispersion mills are dedicated to a particular type of
producttothefullestextentpossible. Thededicatedmills
are not cleaned. The non-dedicated mills are purged with
•solventor waterattheendof thedispersionprocessandthe
wash material is mixed with the dispersed product in the
let-down step.
In the let-down step (see Figures A-4 and A-5), the
dispersed pigments from milling operation are mixed in
portable or stationary tanks with additional diluents, res-
ins, and additives. The tanks have capacity varying from
50 to 10,000 gallons. The additives constitute bactericides,
fungicides, surfactants, defoamers, or extenders. The
bactericides and fungicides used for water-based batches
are mercury-based whereas non-mercurials are used for
solvent-based batches. Solvents such as diethylene glycol
or propylene glycol are added to water-based paints to
extend the drying time and act as an anti-freeze in cold
climates.
The stationary tanks have a capacity greater than 400
gallons while the portable tanks have a 50- to 400-gallon
capacity. About 25 percent of the total number of batches
are let down using portable tanks, which accounts for less
than 10 percent of the total paint volume produced at Plant
A. The mixing in the tanks is performed using turbine
mixers. When the propertiesof the batch reach therequired
standards, the mixing is stopped. The tank contents are
then pumped through bag filters to the filling unit, which
can fill five gallon, one gallon, 1/4 gallon, or 1/2 pint cans.
WASTE DESCRIPTION
The principal waste streams generated by Plant A include
the following:
• Equipment cleaning wastes
• Obsolete stock
32
-------
Empty bags
nhd cans
Rinse
Pigments
Water or
Solvents
Additives
Resins
Emulsion or slurry
Dispersion
bst-Down
See Figs. A-4.A-5
Mill rinse with
water or solvent
Figure A-2. Dispersion and Let-Down Steps - Prevalent Route
Jh
ts
11
t
«
•58 Note: The process shown in this diagram is used in less than
5 * 5% of tfie eases. The most commonly used procedure for
primary dispersion is shown in Figure A-2.
Pigments
Water or
Solvents
Additives
Resins
r
Emulsion, slurry or
drypigmemts „,
1 r~~
1 ' '
J
r*" lit
fff.
Batching ^ Dispersion —
i A
Mill rinse with
water or solvent
t^1 Cleaning
See Figs A-6, A-7
^
nse .
l
l
1
1
Hj ^ Lot-Down
1 See Figs A-4, A-5
f
~^i
•
Figure A-3. Dispersion and Let-Down Steps - Minor Route
33
-------
6J911II «*—
Deq juads
snids «*—
•
siiids ^~
t*
ii*
fl
J W CO
t
|
_
I. |* *•
4 II E
i
• A
i <£
c 1
r— fi
=
* )
\J
—
1 ^ A
^ 1— 1
^ y
(1
Mil it
en o>
o a-
r»
<
O)
o:
£
£
a
a>
«
o
I
(9
i
1
£
O)
5 in
s 8
jalnt residues are a ml
ationary tanks.
s than 5 percent of the
•5«.S
ll-S
ill
» 1 §
£ "C O
in
«
O
5
I
<
2
a.
(D
H-
5
n
o
^
o
o
2
0)
a.
O
c
0
O
3
•
gn
£
3
0)
il
34
-------
T
•*• II
O. a
E£
QJ O
.1
o
-^•
~^
-+>
-+-
•B •
01 en
£ S
£ *»(
f
9 •»
VI f
^ n s
n
a
75
M
I
o
a.
c
JO
S.
S.
O
o
9
t
o>
ili
t^
<
O> o
Q3 Ul
73 a>
.0 g
35
-------
<
**
E
To
o>
775
I
(0
0)
O
I
To
(0
0)
0>
O)
(0
to
£
D)
36
-------
Alkaline Cleaning
1+—
Dirty
Tank
57
I
Clean tank
return
Alkaline
Cleaning
Machine
(Makeup
• solution
Sludge
(Intermittent Stream)
See Note
NOTE: The alkaline sludge and
the rinse water stream are
processed separately and
are not allowed to mix. The
same separation tank is used
uor handling both streams,
but at separate times. When
treating alkaline sludge, add
neutralization i s used.
1*1-
Rinse water from
cleaning of
stationary tanks
See Note
Water
Aqueous Wash Residuals Reclamation System
Required Settled
raw materials solids
Floceulants
Filling
Clarified & decanted
waste water to sewer
Figure A-7. Alkaline Cleaning of Portable Tanks and Aqueous Wash Residuals
Reclamation at Plant A.
37
-------
• Returns from customers
• Off-specification products
- Spills
• Spent filter bags
• Empty bags and packages
TableA-2showsthevarious waste streamsalongwim
their origin and treatment/disposal methods used in the
pastandpresenL Thewastegenerationratesforindividual
streams could not be established. Figure A-8 shows the
amountofwastelandfflledbyPlantAsincel982. Asseen
from this figure, landfill disposal is no longer employed.
Rom Table A-2, it is seen that the waste management
methods haveevolvedinto the presentstate.wheremostof
thewastesareiecycled,reused,orreworked. Thefollow-
ing sections discuss each of these waste streams.
Equipment Cleaning Wastes
Theprocessequipmentisroutinelycleanedtoprevent
product contamination and/or to restore operational effi-
ciency. Theresulting cleanup residuals constitute a major
wastestreamgeneratedbythe facility. Mostofthecleanup
wastes generated at Plant A are reprocessed into market-
able products.
Mill cleaning. The mills are dedicated to a single type
of product whenever possible. In such cases, post-batch
cleaningof themillsisnot necessary. If dedication of amill
to a single product is not possible, e.g. due to demand
fluctuation, then cleaning is necessary. Cleaning is ac-
complished by flushing'the mill either with water or a
solvent, depending on the batch. The flush is then mixed
with the batch in the let-down step. Thus, mill cleaning
does not produce a disposable waste at Plant A.
t
UN
181
(M .
M»»IWMh
UnfflM "• _
IN _
4M «
M _
4-
W.1
1
4- 4-—-I
1M1
Ytir
Rgurt M. Anxsurt et W«H UndfllW by Flirt A tine* 1982
Portabletankcleaning. Portable tanksarefirstscraped
manually to remove residual clingage. Next, the tanks are
washed with highpressurejetsof acommerciallyavailable
alkaline cleaning solution. The cleaning solution is
recirculatedandtheblowdownorpurgeissenttowastewa-
ter treatment. Thisprocess consists of flocculation and pH
adjustment The clear water effluent is drained to the
sewer and the settled solids containing 70 to 75-percent
water are sent to a blending tank (see Figure A-7).
Blending with new material produces a beige-colored
coating which is sold as a general purpose coating.
Stationary tank cleaning. The stationary tanks are to
alarge extent dedicated to the making of a single product.
In such cases, the residue on the tank walls (clingage) is
allowed to build up "to a certain thickness, before being
scraped off manually. Following the manual cleaning, no
further rinsing is necessary. The scraped paint residues
were drummed and disposed of in a landfill until Septem-
ber 1986. Since thattime,PlantAhasdevelopeda process
to rework these residues into a useful product.
Non-dedicated tanks are rinsed with high pressure jets
of water or hosed with solvent depending on whether the
tank is used for water- or solvent-based product prepara-
tion. The rinse water is sent to a holding tank where it is
blended with other aqueous wash streams to produce a
general purpose paint following flocculation and pH
adjustment. The rinse solvent is reused several times and
then sent to an on-site still, where the solvent is recovered
for reuse. The distillation bottoms are convened into a
primer product by blending with solvents and other addi-
tives.
Filling unit cleanup. Separate filling units are used for
water- and solvent-based paints. Filling units for water-
based products are rinsed with water. The rinse water is
sentfortreatmentas described previously. The fillinglines
used for solvent-based paints are back-flushed with a
compatible solvent into the tank from which the product
was drawn. The spent solvent is then reused or sent to the
solvent recovery still, as described previously.
Container cleaning. The small containers (cans, pails,
etc.) containing residual paint are sent for metal reclama-
tion without any on-site cleaning. Containers in which
mercury-based bactericides are delivered are returned to
the supplier without any cleaning.
Obsolete Stock
Obsolete stock is the paint that is no longer marketed
or raw material that can no longer be used. The obsolete
paints that are made by Plant A are reworked into other
marketableproducts. The obsolete raw material is returned
to the suppliers.
Returns From Customers
As with the obsolete stock, the returns from customers
are reworked at Plant A into other products and the empty
containers are sent off-site for metal reclamation.
38
-------
Table A-2. Origin and Treatment/Disposal of Paint Manufacturing
Process Wastes at Plant A
Waste Description Process Origin
No.
1
6
7
Equipment
cleaning wastes
Obsolete stock
Returns from
customers
Off-spec.
products
Spills
Filter bags
Empty bags and
packages
Solvent cleaning of
process equipment
Water cleaning of
process equipment
Alkalinecleaning of
Process Equipment
Mechanical cleaning of
process equipment
Paint that is no longer
marketed or out-dated
raw materials
Unused or spoiled paints
returned by customers
Spoiled batches
Accidental discharges
Filtration of paint
Unloading of pigments
and other additives into
mixing tanksNotes:
Treatment/Disposal Method
Before 1983 19EU 1985
D E A A
F: before
1976
G: stalled
in 1976
F: before
1976
G: started
1976
C
G,H
B
G,H B
B
B
B
1986
A
B
B
B
B
B
A-Reused to the extent possible, distill on-sfte to recover solvent, rework still bottoms
B-Blend to make a marketable product
C-Landfill disposal (Discontinued in September 1986)
D-Off-site recycling
E-Same as A except that the still bottoms are land disposed
F-Overilow discharge to the sewer and landfill disposal of the solids settled in weirs
G-Flocculation followed by discharge of decanted water to the sewer and landfill disposal of the settled solids
H-Vacuum filtration
l-Sanitary landfill after washing
39
-------
Off-Specification Products
Off-specificationproductsaretheresultofbadtotches
thatarecausedbyeirorsinbatchfonnulationorthefailme
ofqualitycontroltodetectoff-specificaudnrawmatenals
At Plant A, the off-specification-products are reworked
into olher usable products.
SpWs
Spills areinadvertentdischarges that occur at various
places in theplant. AtPlant A, the spills are scooped up to
thefullestextentpossible. If the scooped up materials are
water-based then they are sent to the water treatment unit
If they are solvent-based then they are sent to the solvent
recovery still. The spills that cannot be scooped up are
cleaned with commercially available adsorbents. Theuse
of "dry" cleaning methods over manual scooping is dis-
couraged, since it is difficult to rework the adsorbents
containing the spilled material.
Filter Bags
Plant A uses bag filters for all filtering applications.
Cartridgefiltersarenotusedduetotheassociated disposal
problems. The spent bag filters (used for both water- and
solvent-based products) are washed and dried and dis-
posed of as non-hazardous waste.
Empty Bags and Packages
Plant A has eliminated the use of all hazardous lead
and chromate pigments, as most of the paints produced by
Plant A are for use by the general public. Therefore, the
presence of residual pigments does not make the bags/
' packages hazardous and thus they are disposed of as non-
hazardous waste. In addition, since the pigments used at
Plant A are mostly in slurried form, the use of pigments in
bags and packages is limited.
Assessment Phase: Option Generation
The consultants reviewed the plant operations data
obtained prior to and during the site inspection. They
developed a set of waste minimization options based on
this informationandoninformationinthe literature. These
options were screened for their effectiveness in reducing
waste and for their future implementation potential. The
plantmanagerparticipated in this screening, with theresult
that there was general consensus on the list of recom-
mended options.
SOURCE REDUCTION MEASURES
The following paragraphs describe the application
and use of source reduction measures to various waste
streams at Plant A.
Equipment Cleaning Wastes
This stream constitutes a large portion of the total
waste generated. The following source reduction meas-
ures are in current use:
Replacement of caustic cleaning solution
In the past, the portable tanks and small containers
were cleaned with caustic solution. Three years ago, the
caustic cleaning solution was replaced by a proprietary
alkaline solution. As the replacement frequency of this
cleaningsolutionishalfthatoftheregular caustic solution,
the cleanup residuals' volume was cut nearly in half.
Use of high-pressure spraying systems
In the past, the water-based process equipment was
rinsed clean with water from low-pressure hoses. Since
this procedure generated a large quantity of wastewater a
portable high pressure spraying system was purchased.
This modification contributed to a reported 25 percent
reduction in cleanup waste volume.
Dedication of let-down tanks
The let-down tanks that make white paints are dedi-
cated to making whites alone which minimizes the inter-
mediate washing of these tanks. The deposits in thestation-
ary tanks are allowed to build up for a period of time and
thenarescrapedoff manually. Dedication of the stationary
tanks contributed toa reportedSto lOpercentreductionm
associated cleanup waste volume, when compared to a
' previous situation where the tanks were not dedicated and
hence required cleaning after each batch.
Proper batch scheduling
AtPlant A, certain batches are sequenced in the order
of light to dark paint manufacture. This scheduling often
eliminates the need for intermediate cleanup steps.
Pigment substitution
Plant A has already eliminated the use of lead and
chromium pigments, since these pigments are prohibited
from use in consumer products.
The only place where a future raw material substitu-
tion will reduce the degree of hazard is for mercury-based
bactericides. Non-mercury-based bactericides have re-
placed mercury-based counterparts in all solvent-based
paints butnot in water-based formulations. Plant A contin-
ues to use mercury-based bactericides for water-based
paints since their search for effective non-mercury substi-
tutes was unsuccessful. It is suggested that the search for
the substitutes should continue in spite of continual set-
backs.
40
-------
Obsolete Stock
Prevent obsolescence of raw material.
Prevention of raw material obsolescence is accom-
plished by careful control and monitoring of the inventory.
The raw material is used up as quickly as possible to avoid
expiration or degradation. The raw materials are accepted
from the suppliers only when they meet stringent quality
control standards. When a raw material becomes obsolete,
it is returned to the supplier.
Prevent obsolescence of finished stock
Obsolete finished material can be virtually eliminated
by proper production planning and inventory control. The
current manual inventory control system is very efficient in
limiting the obsolete stock. The company is planning to
purchase a computerized raw material inventory control
system. The computerized system is expected merely to
provide more detailed information about the inventory in
a shorter time period.
Off-specification Products
The off-specification products are reworked on-site to
produce marketable products. To achieve additional sav-
ings in reprocessing cost, however, reduction of off-speci-
fication product generation can be further promoted by
proper quality control of the raw material, increased proc-
ess automation, and by ensuring effective cleanup of
equipment. Tight control measures have been extremely
effective at Plant A.
Spills
As mentioned previously, the spills are first recovered
by manual scooping, then reworked into useful products.
Only the residuals remaining after the recovery are subject
to "dry" cleaning using adsorbents. Direct use of adsorb-
ents (i.e. without prior recovery) is discouraged as the
resulting waste is difficult or impossible to reprocess.
Filter Bags
The use of cartridge filters was eliminated since their
disposal proved problematic. Plant A, at present, uses bag
filters forall purposes. These filters arereused to the extent
possible. The spent bag filters when rinsed and dried are
not considered hazardous waste.
Empty Bags and Packages
Use of non-hazardous pigments.
As none of the pigments used atPlant A are hazardous,
the empty bags and packages containing residual amounts
are not considered hazardous.
Use of 'pigments in slurry form.
Most of the pigments used by Plant A are in slurry or
paste form, and therefore, the inse of bags and packages for
pigments is minimal.
Use of water-soluble bags.
Some of the mercury-based bactericides are delivered
to Plant A in water-soluble bags. These bags are added to
the batch along with the bacitericides, thus avoiding the
generation of waste in the form of empty bags and pack-
ages.
RECYCLING AND RESOURCE RECOVERY
MEASURES
Waste segregation, on-site recycling, and off-site re-
cycling were evaluated for their effectiveness in reducing
waste generation at Plant A. These are discussed in the
following paragraphs. ~
Waste Segregation
Segregate water- and solvent-based wastes.
The solvent-based equipment cleanup wastes are
segregated from the water-based wastes. This facilitates
the rework of both these streams into marketable products.
The solvent- and water-based wastes are reworked as
shown in Figures A-6 and A-7, respectively. The rework
strategies shown in these figures would not be effective if
the waste streams are allowed to mix.
Segregate alkaline cleanup wastes from rinse water
wastes.
The alkaline cleanup wastes are segregated from rinse
water wastes. Both these waste streams are separately
reworked (see Figure A-7) into useful products.
On-site Recycling
Reuse of water-based equipment cleanup wastes.
In the past, partially dewatered cleanup wastes were
landfilled. Ten years ago a ilocculation step was intro-
duced to remove the solids prior to discharging the stream
to the sewer. The flocculated solids containing 70 to 75
percent water were disposed of in landfills. Six years ago
this procedure was again modified by adding a vacuum
filter to reduce the water content in the disposed solids to
30-35 percent
Since all these process modifications still involved
disposal of solids in a landfill, Plant A decided to pursue
other process changes that would eliminate such disposal.
This decision was based, in part, on anticipated landfill
ban. Currently, the water-based equipment cleaning wastes
are blended with additives after fiocculation to generate a
beige-colored product (see Figure A-7) which is sold as a
general purpose paint Thus, by rework, the landfilling of
water-based equipment cleanup wastes is avoided alto-
gether.
41
-------
Reuse of alkaline cleaning wastes.
The alkaline cleaning of portable tanks generates a
wastestream. This stream is segregated fiom the aqueous
wastes describedin the previous paragraph, but processed
mtheexactsameniaimer(flocculation,pHadjustmeiitand
blending) to produce a marketable product (seeFigureA-
7).
Reuse of solvent-bearing cleanup wastes.
The'cleanup solvents are reused several times for
rinsingtanks. Thisprocedureensuresthatthetotalsolvent
usageforclearungisminimized. Whentherinsesolventis
considered too dirty for direct reuse, it is distilled on-ate.
The solvent reclaimed by distillation is recycled Jo the
cleaning operation. The distillation bottoms are sent to a
holding tank, where they are blended with solvents and
o!herrawmaterialstoproduceaprimerproduct(seeFigure
A-6).
Rework wastes.
All of the wastes due to customer returns, scraped
paint residues, obsolete finished products, off-specifica-
tion products, and scooped up spills are reworked into
marketableproducts. Proper identification of thecustomer
returns is central to determining the rework strategy for
this waste. For the scraped paint residues (generated due
to the mechanical cleaning of stationary and portable
tanks). Plant A has developed a process to rework these
residues into a useful product. This process is currently
being refined.
Off-site Recycling
In thepast,thesolvent-basedcleanup wastes were sent
to an off-site recycler for reclamation. The reclaimed
solvent was purchased from the recycler and reused. As
this process proved expensive, Plant A discontinued off-
site recycling four years ago in favor of on-site recycling.
At present, off-site recycling is practiced only on an oc-
casional basis.
Feasibility Analysis Phase
The recommended options were evaluated for their
technical and economic feasibility by the consultants, who
obtained cost and performance data from vendors where
new equipment was recommended. The result of the
technical and economic feasibility analyses was a list of
feasible options, which became part of the assessment's
final report. The next waste minimization assessment
phase, Implementation, was left to the discretion of the
paint manufacturer, Plant A.
reduction options employed are essentiany good operating
practices, and hence did not require a large capital invest-
ment However, the rework strategies and their evolution
didrequirealargeR&D expenditure. The implementation
of these measures seemed to be guided more by the
intuition and foresight of the plant personnel than by the
calculated benefits that may have been indicated by a
specific detailed economic evaluation.
The plant personnel indicate that the increase in oper-
ating expense for rework has been matched by .the in-
cre^edrevenuesduetothesaleofreworkedproducts.The
avoided disposal costs, however, are expected to be quite
significantln 1984,181 tons of waste (equivalents about
660 fifty-five gallon drums) was landfiUed (see Figure A-
8) In 1985, due to a comprehensive rework strategy, no
wastewaslandfilled. UsinglandfiUdisposalcostsof$155/
drum,PlantAsaved$102,000 in avoided disposal cosuas
compared to 1984. By reducing its waste from the 1982
level of 1226 tons landfiUed, over the years 1983-1985
Plant Aavoidedpayingatotalof$1.78miUioninlandfiU
disposal costs. This assumes that waste generation would
have remained constant without waste minimization - a
conservative assumption since production rates actually
increased somewhat.
MEASURES
Table A-3 lists the various source reduction measures
noted above for each waste stream. Table A-4 lists the
recyclrngandresourcerecovery options. Each measure is
qualitatively rated on a scale of 0 (low) to 10 (high) for its
waste reduction effectiveness, extent of current use, and
future appUcation potential. The waste reduction effec-
tiveness indicates the amount of waste reduction that is
possible by implementing a particular source reduction/
recycle measure. The extent of current use, as the name
implies, is a measure of current usage of a particular waste
reduction option. The future appUcation potential is a
qualitative measure of the probability that the measure
would be implemented in the future. This probability is a
function of the cost, degree of technical risk, and the extent
of current use.
batch formulation, and washing and drying filter bags pnor
The specific economic aspects of implementing each to disposal.
42
-------
I
Table A-3. Summary of Source Reduction Measures for Plant A
Waste ' Extentof Future
Waste • • Reduction
Source Control Methodology ' Effectiveness
Equipment 1. Replacement of caustic
Cleaning cleaning solution
Wastes 2. Use of high-pressure
9 spraying systems
- 3. Dedication of let-down tanks
4. Proper batch scheduling
5. Pigment substitution
6. Use of non-meercury
bactericides
Obsolete 1 . Prevent raw material
Stock obsolescence
2. Prevent finished stock
obsolescence
Off-Spec 1. Ensure proper
Products batch formulation
Spills 1. Discourage dry
cleanup methods
Filter Bags 1 . Wash and dry
before disposal
Empty 1. Use non-hazardous
Bags& pigments
Packages 2. Use of pigments
in slurry or paste form
3. Use of water-soluble bags
Table A-4. Summary of Recycling and
Recycling/Resource Control Methodology
Recovery Measure
9
7
9
9
10
10
10
10
10
9
10
10
8
5
Resource
Waste
Reduction
Effectiveness
Waste Segregation 1 . Segregate water
and solvent wastes
2. Segregate water
and alkali wastes
On-Site resyciing 1 . Reuse rinse
water wastes
2. Reuse alkaline
cleanup wastes
3. Reuse solvent-10
bearing cleanup wastes
4. Rework wastes
Off-Site recycling 1. Off-site reclamation/
incineration
10
10
10
10
10
10
2
Current
Future
Current Application Reduction Reduction
Use
9
8
10
10
10
0
10
10
10
9
10
10
8
10
Potential
1
3
0
0
0
8
0
0
0
1
0
0
5
0
Recovery Measures for
Extent of
Current
Use
10
10
10
10
0
10
1
Future
Application
Potential
0
0
0
0
10
0
0
Index
8
6
9
9
10
>==>
10
10
10
8
10
10
6
==>
5
Plant A
Current
Index
0
0
0
0
0
8
0
0
0
0
0
0
1
0
Future
Reduction Reduction
Index
10
10
10
10
0
10
0
Index
0
0
0
0
0
o
43
-------
waste generation at present and therefore given a zero
future reduction index in Table A-4. The use of non-
mercury bacteriddes and the use of pigments in slurry or
paste form are rated high for future application potential.
Thesetwomeasures,however,haveavery lowimpacton
reducing waste volume because these processes generate
only a small volume of waste.
SUMMARY
The data on production and waste generation rates for
Plant Afor 1982 to 1985 can be used to determine specific
waste generationrates Ob waste/gal product). Theserates
are plotted in Figure A-9. The waste reduction program
used by Plant A is clearly effective; the specific waste
generation rate was reduced from 0.34 Ib/gal in 1982 to
zero in 1985. The following factors contributed to this
successful waste reduction effort at Plant A:
• ProperplanningandforesighLTheproblems
associated with off-site waste disposal were
anticipated well in advance and measures
were implemented ahead of time. Total
eliminationoflandffll disposal wasagoal set
by management Waste minimization and
other environmental issues are given high
priority.
• properperspectiveofthewasteminimization
issue. Good operating practices contributed
to successful source reduction, recycling,
and reworking of all the wastes generated.
Theresearchanddevelopmenteffortresulted
in the formulation of new products from the
waste and at the same time reduced the need
for disposal.
• Experienced employees. The average
seniority is well over 10 years for the
employeesatPlant A. Because theemployees
understand the process very well, mistakes
that result in waste generation are few and
infrequent.
• Product usage. Most of the paints produced
by Plant A are for use by the general public.
For this reason, extreme care is taken in the
choice of raw material and product
formulation. This is seen hi the rapid
replacemenfofsblvent-based formulations
by water-based formulations in the
architecturalpaintscategoryinthelastdecade.
Productvariety. Mostofthepaintsproduced
at Plant A are water-based latexes and
blending of waste latexes to produce a
marketable product is easier than for non-
Jatexpaints. Hence, wastereuse,by blending,
to produce a marketable product may not be
a viable option for industrial paint
manufacturers who produce solvent-based
acrylics, epoxies, mrethanes and other
products.
. Marketing outlets. Plant A markets its
products through retail outlets and
commercialservicecenters. Anynewproduct
resulting from reworking processes can be
easily sold from these outlets using price
discount programs. Also, because home
mteriorpaintispurehasedforaesthetic rather
thanfunctionalattributes,consumersaremore
liberal in experimenting with new products.
The same advantage may not pertain to
industrial paint manufacturers, where the
functions of the products limit their usage
and marketability.
u -
03 -
Pmfcof
Vafcfcr
atari U "
Predict
0.1 -
0.0 _
OJ37
BJW
Ott
0
»« 1H1 1IU 1IU
YHJ
Figure A-9.
44
-------
Reference
DHS. 1987. Hazardous Waste Minimization Audit
Study ofthePaintManufacturinglndustry. April24,1987.
Prepared for California Department of Health Services,
Alternative Technology Section (Sacramento, California)
by Jacobs Engineering Group Inc.
45
-------
PLANT B WASTE MINIMIZATION ASSESSMENT
The waste minimization assessment of Plant B fol-
lowed the same protocol used for Plant A, and included:
• Planning and organization
• Assessment phase
• Feasibility analysis phase
Implementation of selected waste minimization op-
tions was left to the discretion of Plant B.
Planning and Organization
Planning and organization of the assessment were a
jointeffonoftheconsulnngfirmandthepaintmanufactur-
ing plant's operations manager. As summarized in Figure
1, this phase of the assessment involved getting company
managment commitment to the project, setting goals for
the assessment, and establishing a task force (the consult-
ants working in cooperation with the plant operations
manager) to conduct the assessment.
Assessment Phase: Process and Facility
Data
The consultants worked with the plant operations
manager to establish a data base of the facility's raw
material needs, materials handling procedures, and opera-
tions processes. Block flow diagrams were drawn up to
identify where materials are used and where waste is
generated. Initial study of this infbrmati on and discussions
of was te stream concerns at the plant served as preliminary
steps to thesiteinspection.during whichadditionalprocess
and waste handling information was obtained.
FACILITY DESCRIPTION
Plant B produces a wide variety of industrial coatings.
About 90 percent-are solvent-based;,the remainder are.
water-based. About 10 years ago, the water-based paints
constituted only 1 percent of total production.
The solvent-basedpaints produced includepigmented
tints, p igmented non-tints, lacquer thinners, unpigmented
paints (clears), and stains. The water-based formulations
are mostly emulsion paints. The production rates of the
major products are listed in Table A-5.
Table A-5. Coatings Produced by Plant B in
1985
Product Production Rat* (gal/yr)
Pigmented products (enamels) „ 2!!°'°°°
Clear products (lacquers & varnishes) 1.220,000
Reducers & solvents 260,000
Stains & fillers 310'000
RAW MATERIALS MANAGEMENT
NumerousorganicsolventsareusedatPlantBinpaint
production. Other raw materials in paint production in-
clude resins, pigments, extenders, and additives. Table A-
6presentstheconsumption rates of the majorraw materials
in 1985.
The selection of solvents used in paint production is
based on the enduse of thepaint the solvents used at Plant
B include methanol, methyl ethyl keome (MEK), Tolusol-
6, toluene, lacquer thinner, and mineral spirits. The sol-
vents are purchased in bulk or in drums. The solvents in
bulk form are stored in underground storage tanks. The
solvents in drums are stored in an outdoor storage area.
The pigments are delivered in plastic or paper bags,
which are stored in an indoor storage area. The inventory
is typically capable of meeting the production requirement
for two months. In addition to raw materials, some process
intermediates are also stored indoors.
Each of the raw materials is assigned an identification
number for inventory control and product formulation.
The amounts of various raw materials for each batch are
determined through a computer and the data is punched out
• on computer-generated batch cards. The employee at the
production unit follows the instructions given on the cards
and obtains the raw material from the storage area using
the coding sequence for the material.
46
-------
PROCESS DESCRIPTION
The following description highlights the production
ofasolvent-basedpaintatPlantB. The.blockflbwdiagram
for this process is presented in Figures A-10 through A-12.
The production of the paint begins with dispersing the
pigments in either a roll mill or a sand mill. The sand mills
are horizontalorvertical and employ sand/glass/steel bead/
shot to disperse the pigments in a small quantity of solvent/
resin mixture. The primary dispersion is carried out in
batchesof 30 or 55 gallons. Afterpassingthrough the mill,
the mixture of pigments and solvent/resin is collected in
another container and sent to intermediate storage, let-
down, or the next step in production. Sometimes, the
mixture is passed through the mill up to 3 times to achieve
the required degree of dispersion. In such instances, two
containers (feedcontainerandreceiver container)areused.
The same containers are used for all the passes through the
mill, and the containers are cleaned after each pass.
Table A-6. Raw Material Consumption
Rates at Plant B in 1985
No. Material
Solvents
1. Methanol
2. Methyl ethyl ketone
3. Tolusol-6
4. Solvent IB
5. Lacquer thinner (blend)
6. Mineral spirits
7. Filmcol A-4
6. Isobutyl Isobulyrate
Resins
9. Beckosol
10. Coconut Alkyd
11. .t Rhophex WL-91
Pigments
12. Titanium dioxide
13. Yellow oxide
14. Burnt umber
15. Van dyke brown
Extenders
16. Calcium carbonate
17. Talc
18. Clay
Miscellaneous
19. Drying oils
20. Piasticizers
Annual Consumption Rate
48,000 gal.
178,000 gal.
361,000 gal.
186,000 gal.
170,000 gal.
132,000 gal.
82,000 gal.
51,000 gal.
41,515 gal.
33,575 gal.
16,000 gal.
350,000 Ibs.
32,000 Ibs.
51,000 Ibs.
56,000 Ibs.
52,000 Ibs.
128,000 Ibs.
30,000 Ibs.
30,000 gal.
10,000 gal.
The let-down step consists of filling the mixing tank
with the primary dispersions, solvents, plasticizers and
other additives. The solvents are pumped into the tanks
using the filling system isnown in Figure A-13. The
contents are then mixed. .For portable tanks, high-shear
vari-speed mixers are employed. For the stationary tanks
a low-speed mixing is used. When the tank contents attain
theproper viscosity, color.and gloss, themixingis stopped
and the contents are filtered and dispensed into product
containers. The filtration is achieved using bags, cartridge
filters, or vibrating screens. If the tanks are portable, they
aremoved to theflllingareaiuidthecontents are gravity fed
to the filling unit
Thebatch sizes are 55,110,220,300 or 550 gallons for
the portable tanks. Larger batches are prepared in station-
ary tanks with a capacity of 1000,1500, or 3000 gallons.
Figure A-13 shows thelayoutof the tanks in the production
area. The stationary tanks are usually dedicated to one
product and therefore, no cleaning is required between
subsequent batches. At present, the products prepared in
the stationary tanks (in order of decreasing production
quantity) are clears, stains, and enamels. Similarly, the
major products produced using portable tanks are stains,
enamels, and clears.
WASTE DESCRIPTION
The major wastes generated by Plant B are (in order of
decreasing volume): equipment cleaning waste, obsolete
products, returns from customers, off-specification prod-
ucts, spills, filter bags and cartridges, and empty bags and
packages. The sections below discuss each of these wastes.
The solvent waste is sent to an off-site recycler for
reclamation. On-site solvent recovery was conducted in
the past, but was discontinued when it proved too expen-
sive. The off-site recycler charges $0.65/gal.of spent
solvent to reclaim it at 60 % minimum yield and return it
to Plant B. The distillation residues generated during the
reclamation are disposed of at a surcharge of $0.75/gal-
spent solvent. The off-site recycler charges $l/gal if the
solvent waste is incinerated in a cement kiln. The off-site
recycler is planning to substantially increase its service
charges (e.g. S 2.60/gal for incineration) in the near future.
Table A-7 presents the costs (S/ton) of some solvents
used by Plant B. Also presented are some disposal cost
. figures from an off-site recycler.
47
-------
.3
i O)
1 2>
II
i'
UL
n t.
51
I
£
¥ |
*c o
S£
5 •
I
0
_
s
•> •
o
73 e
€ o
• S
E o
r
let-d
a
s.
1*
1-
o
o
52
0)
OL
w
o.
o
2
O)
u.
48
-------
eBpuiieo pue
6eq weds
sessoi
J2
0.
CB
cn
o
Q.
o
o
a
^i
0
a>
a>
49
-------
m
*«
CO
E
CO
o>
i
a
o
o
CM
3
=
O»
\L
50
-------
#<•'
Ill *
eun t
E]
CD
so
o.
>
o
CO
o
=
t
2
eun t
ton
jg:
I
51
-------
Equipment Cleaning Wastes
Equipment such as mills and mixing tanks is cleaned
after each batch in order to prevent cross-contamination.
Unusable storage containers, such as drums and paUs, are
cleaned before sending them for off»site metal reclama-
tion. Theequipmentcleaninggenerates two waste streams:
spent solvent from solvent rinsing operations and paint
sludge from caustic cleaning.
Table A-7. Raw Material Costs and Waste
Disposal Costs
No. Solvant/Wasto Cost($/ton)
1. Lacquer thinner 386-°°
2. Methyl ethyl ketone 470.00
3. Mineral spirits 204.00
4. Recyclables (a) 280.00
A. Incinerables (a,b) 200.00
Notes: (a) AdensityoflOlb/galwasassumedforliquid
wastestreams.
(b) Indicatespricechargedbyanoff-siterecycler
in 1985 and does not include lost raw material
costs.
Mill cleaning
The mills are usually cleaned with a solvent used in
formulation of the next batch. When this is not possible,
methyl ethyl ketone (MEK) is used for cleaning. The
cleaning solvent is let through the operating mill immedi-
ately following the batch. The spent MEK is reused if
contamination is not a problem. Spent solvents from mill
cleaning operation are used directly as part of formulation
if let-down step immediately follows milling. In cases
where the intermediate dispersion is stored for later use, the
flush solvents are collected and reclaimed off-site by an
off-site recycler.
Portable tank cleaning
Manual cleaning with spatulas is used to remove
clingage from portable tanks before cleaning with a caustic
solution. The removed clingage is drummed and sent for
off-site incineration. Following clingage removal, the
portable tanks (and barrels/pails) are cleaned in a caustic
cleaning machine employing a high pressure spray. Gen-
erally, the tanks are cleaned immediately after use to
prevent drying of the residues on the tank walls. When
cleaning cannot be performed immediately after clingage
removal, a small quantity (e.g. one quart) of solvent is
added to the tank to prevent drying of residuals. This
solvent is either lost due to evaporation or removed by the
caustic cleaning. The caustic cleaning solution comprises
600 gallons of water with 475 Ibs of dissolved sodium
hydroxide at 200-205 F. The caustic solution is recircu-
lated and the sludge drawn off into reclaim drums for
disposal through off-site incineration. In 30 percent of the
cases, the caustic wash alone is insufficient, and further
cleaning with a solvent (such as MEK or lacquer thinner)
is required. The solvent wash residuals are drummed and
sentoff-siteforsolventreclamation.Thisadditionalclean-
ing is common for handling acrylic paint deposits. PlantB
is installing a new high pressure nozzle to improve the
cleaning efficiency of the caustic cleaning system.
Stationary tank cleaning
The stationary tanks are usually dedicated to the
production of asingleproducL In such cases, the tank walls
are rinsed with the solvent used in the formulation. The
rinse solvent then becomes part of the next batch. When a
different product is to be prepared in the tank, the tank is
rinsed with three gallons of lacquer thinner before starting
the new batch. The spent solvent is reused for rinsing
whenever possible. When this is not possible, the spent
solvent is drummed and sent to the off-site recycler for
reclamation/incineration.
Filling unit cleanup
The filling unit consisting of a positive displacement
pump, filter, and associated piping, is solvent-cleaned
between filling campaigns of different products. Prior to
solvent cleaning, the residual paint is emptied from the
suction side into a container using the pump. The residual
• paint from inside the filter housing and the discharge side
is normally drained into a separate bucket, and combined
with the product MEK is then used for rinsing the filling
unit The spent MEK is reused if possible or drummed and
sent to an off-site recycler for reclamation/incineration.
Turbine mixer cleaning
The turbine mixers used for let-down in portable tanks
are also solvent cleaned. Here, the mixer is lifted from the
mixing tanks, lowered into a barrel containing solvent, and
then rotated. The solvent in the barrel is reused several
times before being sent off«site for reclamation/incinera-
tion. Prior to solvent cleaning, cleaning with brushes is
sometimes employed.
Returned product container cleaning
The returned tote bins containing residual paint are
cleaned by an off-site contractor. Before sending the
drums, pails, and cans off-site for metal reclamation, they
are cleaned either on-site or off-site. In the past, the
containers could be sent for metal reclamation without any
cleaning. At present, the reclaimers do not accept un-
cleaned containers.
52
-------
Obsolete Products
Obsolete products are mostly paint that is no longer
produced or marketed. These materials are usually re-
worked into marketable products. When this is riot pos-
sible, they are sent to an off-site recycler for reclamation or
incineration. Unusable shipping containers that contain
some leftover paint are a part of this stream. These pails
may be washed on site or sent off-site for cleaning. After
cleaning, the pails are sent for off-site metal reclamation.
Returns from Customers
Unused or spoiled paints are often returned to Plant B
by their clients. These returns are accepted to maintain
good customerrelations. After lab analysis, some of these
wastes are reworked into marketable products and the
remainder is sent to an off-site recycler for reclamation/
incineration. The containers that are returned by the
customers are handled in the manner discussed in the
previous paragraph.
Off-specification Products
Off-specification products are usually generated by
any of the following occurrences:
• Errors in the computer codes for the raw
materials. This can cause the operators to use
the wrong materials or formulation for the
batch.
• Spoiled or degraded raw materials. The raw
material are routinely tested; however, time
and production constraints sometimes result in
the quality control steps being by-passed.
• The "rework" material may sometimes be
introduced into a wrong batch.
• Contamination due to improper cleaning of the
tank.
The average seniority of employees at Plant B is about
10 years and the employees have considerable experience,
which makes errors in batch formulation infrequent. The
off-specification products are usually reworked. When
this is not possible, they are sent off-site for reclamation/
incineration.
Spills
Spills are inadvertent discharges of paint that occur in
the productiorrarea.--Spills are usually cleaned by '"dry"
methods. Saw dust or sand is sprinkled on the spill and then
scraped up and drummed for disposal in a landfill. The area
is then mopped with a thinner.
Filter Bags and Cartridges
The spent filter bags and cartridges are disposed in a
landfill. As of November 8,1986, this waste may not be
disposed of in a landfill if the ;solvent content is more than
1 percent. Plant B is considering alternative disposal
options incrudmg'theiise of an-off-site incinerator.
Empty Bags and Packages
The pigmentsare usually delivered in paper bags. The
empty bags and packages containing traces of pigments
are hazardous waste and are Dialed and sent to a landfill for
disposal.
WASTE GENERATION RATES
Table A-8 presents the individual waste streams along
with their origin, treatment/disposal, and their generation
rates in 1985. Generation rates for waste streams such as
obsolete stock, customer returns, off-specification prod-
ucts and spills are not documented separately at Plant B;
these figures are included in the equipment cleaning waste
generationrate shown in Table A-8. The amount of solvent
consumed in cleaning operations is about 1500 gallons per
month, which gives a measure of the equipment cleaning
wastes. The caustic wash process generates about 220
gallons of sludge per month.
Assessment Phase: Option Generation
After the site inspection, the plant operations manager
and the consultant team reviewed the raw material, proc-
ess, and waste stream information and developed a number
of waste minimization options for consideration. These
options fall into the categories of source reduction tech-
niques and recycling and resource recovery techniques.
SOURCE REDUCTION MEASURES
Equipment Cleaning Wastes
Equipment cleaning wastes constitute the major por-
tion of the total wastes generated by Plant B. Both existing
and new source reduction measures can be effective in
reducing this waste stream. These measures fall into four
general categories:
• Raw materials substitution
• Process modification
• Equipment modification
• •..Improved operating practices
Raw materials substitution
Plant B uses lead and chiromate pigments for making
special primers. The use of these pigments should be
53
-------
Table A-8. Origin, Treatment/Disposal, and the 1985 Generation Rates of Paint
Manufacturing Process Wastes at Plant B.
No. Waste
Description
1 Equipment
cleaning
wastes
Obsolete
products
Returns from
customers
Off-specification
products
Spills
Filter bags
and cartridges
Empty bags
and packages
Process Origin
Equipment cleaning using
solvent. Equipment
cleaning sludges
removed from the caustic?
cleaning solution.
Paint that is no longer
produced or marketed,
obsolete raw material
Unused or spoiled paints
returned by customers
Spoiled batches
Accidental discharges
Filtration of paint
Unloading of pigments
and other additives into
mixing tanks
Treatment/Disposal
Sent to OSCO for off-site
reclamation/incineration
Sent to OSCO for off-site
incineration
Some of it is reworked &
the rest is sent to OSCO
Some of it is reworked &
the rest is sent to OSCO
Some of ft is reworked &
the rest is sent to OSCO
Dry cleanup followed by
landfill disposal of the
spent absorbents
Landf illed at present,
planning alternate means
of disposal
Landfilled
Generation Rates, Short Tons
Solvents Solids Sludge Total
14815 75 N/A 223.5
N/A N/A 13.2 13.2
1 N/A
N/A Unknown N/A 0.1
Notes:
- Data included in the equipment cleaning wastes
N/A • Not applicable
54
-------
reduced or eliminated to the fullest extent possible.
Equivalentfoimulationsusing less hazardouspigmentsare
commercially available (e.g. the no-lead and no-chrome
alternatives marketed by Halox Pigments) and should be
tested for customer acceptance. Chrome yellow pigment
can be substituted for by organic pigments or yellow iron
oxide. However, the color obtained with yellow oxide
pigments is not as bright when compared with chrome
yellow counterparts: Customer acceptance is viewed as a
major obstacle.
Process modification
• Improved production planning. The mills are
usually cleaned with a compatible solvent
thereby generating a stream that is used in the
let-down formulation. However, this is not
done if the pigments are dispersed for
subsequent storage. In the latter case, MEK is
used to clean the roll mill By planning the
production schedule in such a way that the
pigments are dispersed only before a batch
formulation (thus eliminating the need for
intermediate storage), the spent MEK wastes
can be minimized. Alternatively, the mills can
be cleaned with a small amount of compatible
solvent to be combined with the batch that is
destined for intermediate storage.
• Recirculation through the mill. Recirculating
the mixture of pigments and solvent through
the millandretumingthemtothesamecontainer
shouldbeexplored. Thisprocessavoidstheuse
of asecondcontainerforcollecting the material
from the mill, with the elimination of one
cleaning step. This method has more potential
for waste reduction in cases where multiple
passes through the mills are necessary. The
; disadvantage of this method is that fine,
dispersed pigments are allowed to mix with
undispersed pigments before going through the
mill again. This may reduce the efficiency of
the mill and require running the mill for a
longer period of time. Excessive degradation
of the polymers (resins) can also be a problem
with this recirculation scheme. The economics
of increased power consumption should be
weighed against the reduction in labor required
for cleaning plus the reduced disposal costs.
• Replacement of caustic solution. The caustic
solution used for cleaning can be replaced by a
more stable cleaning fluid. Somecommercially
available alkaline cleaners were found to be an
effective alternative by other users. There are
no expecteddisposal problems associated with
theuse of these formulations. Onesuch washing
agent, when substituted for caustic solution at
another facility, reduced the cleaning solution
replacement frequency by a factor of two.
• Caustic wash sludge dewatering. The sludge
generated from the caustic cleaning system is
generally drummed for disposal. Dewatering
the sludge by flocciilation, filtration, or
centrifugationcanminirnizethis wastevolume.
Adding de-emulsifiers to the rinse water can
also break the emulsion and decrease the
sludge volume.Thespeiit rinsewatershouldbe
allowedtosetfleforaniidequateperiod of time
to allow forcomplete solids separation. Itshould
be noted that dewatering, while effective as a
cost reduction measure, has few, if any,
environmental benefits.
Equipment modification
• Mechanical cleaning. Use of mechanical
devices for cleaning the tanks is currently
practicedonlyonsmallianks. Thepaintresidues
are removed with a spatula before sending the
tank for caustic cleaning. For larger tanks, the
use of rubber/metal blade wipers appears to be
limited.
• High-pressure nozzle replacement. Plant Bis
replacing the existing high pressure nozzle
used for caustic spray cleaning with a more
efficient unit. Increaised cleaning efficiency
will contribute to a reduction in the solvent
cleaning currently necessary in some cases
after the caustic cleaning.
• Replacement of existing mills. The installation
of more efficient mills that would not require
multi-pass dispersions should be considered as
a part of future plant modernization plans.
• High-pressurecleaningof stationary tanks. The
large (stationary) tanks can be cleaned by
efficient high pressure cleaning systems such
as the ones used by Lilly Industrial Coatings in
High Point, North Carolina. This measure
would decrease the total amount of solvent
required for cleaning.
Improved operating practices
• Avoidanceofunnecesiarycleaning. Equipment
should be cleaned only when necessary. For
example, when the primary dispersion is done,
employing more than one pass through the
55
-------
mills, the containers are currently rinsed
betweenpasses-Thisintermediatecleanupcan
be avoided if the product contamination is not
significant In general, the feasibility of
eliminating the cleaning step between
subsequent batches should be explored.
Experiments could be conducted on a small
scale in the laboratory to measure the degree of
contamination resulting. If the contamination
of the products is within the quality control
standards then the cleanup step can be
eliminated.
• Light-toniarkbatchsequencmg.Theschediuuig
of thebatches in such a way that light paints are
produced before dark paints could mean the
elimination of an intermediate cleaning step in
some cases.
• Preventpaintdrying in the tanks. Cleaning the
tanks immediately after use prevents scaling
due to paihtdrying. This also reduces cleanup.
Though a quart of solvent is poured into tine
tank to prevent drying, the tanks may be left
unused long enough for this quantity to
evaporate. Proper coordination between
production and cleaning can prevent such
occurrences.
• Computerized inventory control. There are
several commercially available computerized '
inventory systems-Installationofthesesystems
canimpiovetheraw material trackingandhelp
identify and remedy raw material losses at an
early stage.
• Computerized waste documentation and
control. Computerized waste documentation
and control can help track the wastes in the
process and can help in undertaking control
strategies. Companies offering such systems
(hardware and software) include Waste
DocumentationandControlInc.,in Beaumont,
Texas, and Intellus Corporation in Irvine,
California.
Other Waste Categories
After equipment cleaning wastes, important waste cat-
egories are: obsolete products, returns from customers,
off-specificationproducts,spills,filterbags and cartridges,
and empty bags and cartridges. Recommended ways of
reducing these wastes are as follows:
Obsolete Products
• Proper planning and inventory control.
Obsolete stock can be minimized by proper
planning and inventory control. Currently, the
inventorycheckisdonetwiceayear.By having
acomputerizedinventory system, theinventory
can be checked more frequently and over-
stocking, to some degree, can be reduced.
Returns from Customers
• Customerincentiveprograms.Whencustomers
return unused paint, the paint is reworked into
other products, and the containers are cleaned.
Customersthatpurchaselargevolumesof paint
in drums could be offered cost incentives to
convert to bulk purchase (e.g. 400 gallon Tote
drums). This would seduce the quantity of
returned drums that require cleaning at Plant B
and would also result in reduction of residuals.
The size of the containers used by Plant B's
clientele can be controlled to some extent with
similar incentive programs, if the cost savings
in cleaning are significant
Off-Specffication Products
• Ensure proper batch formulation. Before
making a batch, it is a current practice to
attempt the formulation al;a«mall scale inPlant
B'slabs. Whenlargebatehesofpaintaremade,
the lab scale formulations must be repeated two
to three times to ensure that the formulation is
correct This prevents a large volume batch
from becoming spoiled.
Spills
• Improved training and supervision. Proper
equipment maintenance can prevent leaks, and
increased training and closer supervision can
prevent overfilling and spills during manual
transfer.
• Discourage dry cleanup methods. Dry cleanup
with solid adsorbents is widely used at Plant B
for dealing with spills. Dry cleanup produces
spent adsorbent waste that is not amenable to
reworkandthusneedstobedisposed. Therefore,
dry cleanup should be avoided to the extent
possible, if the scooped up spills can be
reworked.
Filter Bags and Cartridges
• Use bag filters in place of cartridges. Plant B
56
-------
uses two cartridge filtration units, each
containing six cartridges. Disposal of the spent
filter cartridges is an anticipated problem.
Cartridge filters can be replaced by bag filters.
Spent bag filters contain much less paint man
spent cartridges and can be reused several tunes;
however, bag filters are more expensive.
Unreusable bag filters can easily be washed
with solvent and dried prior to their disposal as
non-hazardous waste. Wash solvent can be
combined with other solvent wastes and sent
for off-site reclamation.
Use of wire screens in place of filter bags/
cartridges. Wire screens can be reused almost
indefinitely when backwashed with a solvent
and therefore are preferred to bags/cartridges.
The backwashing process may generate a
solvent-bearing waste. Therefore, the use of
wirescreens isrecommendedonly if this waste
streamcanbereusedorreworkedon-site.Plant
B already uses wire screen filters in two of the
eight filtration units and is currently testing
wire screen filters to replace the remaining
filters.
Empty Bags and Packages
• Use of rinseable/tecyclable drums. Replace-
ment of bags and packages (used for hazardous
materials) withrinseable/recyclabledrumscan
be addressed through inquiries with suppliers.
• Use of pigments in slurry form. Theavailability
of pigments in slurry form should be explored
through vendor contacts. The use of pigments
in slurry form means areduction in waste bags
and packages. The pigment slurry can be
bought in drums or bulk form and the drums
could be returned to the vendor.
• Segregation of empty bags and packages.
Currently, all the empty bags and packages are
baledanddisposed of as hazardous waste, even
though only some of the bags and packages
contain hazardous material Segregating the
bags and packages containing hazardous
pigments (lead or chromate) from those that do
notcontainhazardousmaterialswouldprevent
the rest of the bags and packages from being
considered hazardous. v
RECYCLING AND RESOURCE RECOVERY
MEASURES
The following recycling and resource recovery measures
were considered for the facility:
• Increase recyclability
• On-site recycling
• Off-site recycling
• Waste exchange possibilities
Eachofthesemeasures is discussed in detail in the following
paragraphs.
Increase Recyclability
Maintenance of minimum, solvent content in the waste
The spentsolventfromPlant Bis sent to an off-site recycler
forreclamation^ncineration.Theoff-siterecycler reclaims
the solvent (at a net cost of $1.40/gal) only if the solvent
yield from the waste is more than 60 percent If the solvent
yield is lower, the wastes are incinerated at a cost of $ LOO/
gal. Incineration has an additional cost associated with the
lostsolvent that needs to beieplaced($ 1.57/galforMEK).
It is economically beneficial to generate a waste contain-
ing more than 60 percent sol vent, if off-site reclamation is
theprefenedmethod. Thiscreatesaninterestingconstraint
on all efforts aimed at reducing solvent use at the facility;
the amount of solvent that ends up as a waste destined for
off-site reclamation must be reduced together with the
amountof solids thatsuchawastecontains,e.g. by reducing
clingage prior to cleaning or by improved caustic wash.
Also, the amount of solvent evaporated during miscella-
neous operations must be reduced.
Segregation of the solvent wastes
Recyclability is improved by segregation of the wastes.
Segregation of cleanup wastes containing MEK and lac-
quer thinner should be triedin order to improve therecycla-
bility of both streams. Another alternative involves using
only one solvent (MEK or lacquer thinner) for all cleaning
purposes. This generates a larger, single waste stream mat
is easier to handle.
On-site Recycling
On-site distillation
Plant B has attempted on-site reclamation using a solvent
recovery still. This method, however, proved unprofitable
in the past and was discontinued. This method should be
reconsidered in light of the present disposal costs.
Reuse of cleanup solvent
, Reuse of the cleanup solvent to the fullest extent possible
can reduce waste solvent quantity. Wash solvent from
each (or at least the mostprevailing type) of solvent-based
paint batches can be collected and segregated to facilitate
reuse. The wash solvent can men be reworked into com-
patible batches. One example of such reuse is presented
below.
57
-------
The mills used for primary dispersion are cleaned by
rinsing with solvent The rinse solvent is added to the let-
down tankonly if let-down is theimmediatenext step in the
process. Sometimes the dispersed pigments from the
primary dispersion are sent for intermediate storage. In
such cases, the rinse solvent is drummed for disposal and
sent to an off-site recy cler. The rinse solvent can be saved
inaseparatecontainerandthenaddedtothelet-downwhen
the compatiblebatchofdispersedpigmentsfrominterme-
diate storage is being processed in the let-down tank.
Rework cleanup solvents into useful products
Cleanup solvents from various cleaning operations can be
blended and reworked into a marketable product. This
method wasattemptedwithsuccessby onefirmtoproduce
a primer product
Rework wastes
All of the wastes due to customerretums, obsolete finished
products, off-specification products, and scooped up spills
should be reworked to the fullest extent possible. This is
already being practiced to some extent at Plant B.
Reuse of filter bags
Thefilterbagscanberinsedcleanandreused several times.
This is already practiced to some extent at PlantB. Such
reuse will decrease the volume of spent filter bags that
require disposal.
Off-site Recycling
Off-site recycling is already in effect at Plant B. The
recyclerreclairhs andretums the solvent from the wastes if
the solvent yield from the wastes is more than 60 percent.
However, cost increases are anticipated because of the
increasing cost of insurance to the recycler.
Waste Exchange Possibilities
Information about Waste Exchanges is included in the
following Appendix section: Where to Get Help.
RATING AND SCREENING OF WASTE
MINIMIZATION MEASURES
Table A-9 lists the various source reduction measures
noted for each waste stream. Table A-10 lists the recycling
and resource recovery options. Each measure is rated on
a scale of 0 (low) to 10 (high) for its waste reduction
effectiveness, extent of current use, and future application
potential. The waste reduction effectiveness indicates the
amount of waste reduction that is possible by implement-
ing a particular source reduction/recycle measure. The
extent of current use, as the name implies, is a measure of
current usage of a particular waste reduction option. The
futureapplication potential isaqualitative measure of how
easy it would be to implement, considering cost and
technical feasibility.
According to facility personnel, the most effective source
reduction measure for reducing equipment cleanup wastes
wascausticsludgedewatering. This method wouldrequire
the installation of equipmentfor dewatering. Other source
reduction methods considered effective by the facility
personnel for dealing with equipment cleanup wastes were
avoidance of unnecessary cleaning, replacement of caustic
cleaning solution, and prevention of paint drying in tanks.
The following source reduction methods for dealing with
other specific waste streams were given high ratings by the
facility personnel:
• Proper planning and inventory control for
obsolete stock;
• Customer incentive programs for customer
returns;
• Ensuring proper batch formulation for off-
specification products;
• Improvedtrainingandsupervisionforhandling
of spills;
• Use of bag filters in place of cartridges;
• Use of wire screen filters in place of bag/
cartridge filters; and
• Useofrinseableandrecyclabledrums for empty
bags or packages.
Among the recycling and resource recovery options, re-
consideration of on-site distillation received the highest
rating of 8. This measure would involve the installation of
a distillation unit Other recycling/resource recovery
measures rated highly include reuse of spent solvent,
rework of various waste streams, and the segregation of
solvent waste streams to promote their recyclability.
Feasibility Analysis Phase
After discussions with Plant B personnel, some of the
options discussed in the previous section were selected for
investigation of their technical and economic feasibility.
The economic analysis was based on the raw material and
waste disposal costs provided by the facility personnel and
on economic and technical information provided by equip-
ment manufacturers. The measures evaluated in this sec-
tion include: use of on-site distillation for solvent recov-
ery, caustic sludge dewatering, replacement of caustic
cleaning solution, avoidance of unnecessary cleaning,
replacementof cartridges with bagfilters.andreplacement
of cartridge or bag filters with wire mesh filters. Other
58
-------
Table A-9. Summary of Source Reduction Measures tor PianiB,
Waste Control Methodology Waste Extent of Future Current Future
<££> control Metnoooragy Reduction Current Use Application Reduction Reduction
j Effectiveness
Equipment 1.
Cleaning 2.
Wastes 3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Obsolete 1.
Products
Customer 1.
Returns
Off-Spec 1.
Products
Spills 1.
Filter 1.
Cartridges 2.
Empty 1 .
bags & 2.
Packages
Table A-10.
Waste Source
Raw Material substitution.
Improved production planning.
Recirculation through the mill.
Replacement of caustic solution.
Caustic wash sludge dewatering.
Mechanical Cleaning.
High-pressure nozzle replacement.
Replacement of existing mills.
High-pressure clean stationary tanks.
Avoidance of unnecessary cleaning.
Light-to dark batch sequencing.
Prevent paint drying in the tanks.
Computerized inventory control.
Computerized waste documentation.
Proper planning & inventory control.
Customer incentive programs.
Ensure proper batch formulation.
Improved training and supervision.
2. Discourage dry cleanup methods.
Use bags instead of cartridges.
Use wire screen filters.
Use of rinseble/recyclable drums.
Use of pigments in slurry form.
•
Summary of Recycling and
9
6
2
5
7
5
5
2
2
8
5
5
5
5
5
6
6
6
7
7
7
6
6
Resource
Control Methodology Waste
Reduction
9
6
0
0
0
•5
5
2
2
5
5
3
3
0
3
2
4
4
7
4
3
0
2
Potential Index Index
2
5
2
5
5 •
5
5
2
2
7
5
5
5
5
7
2
6
6
7
6
8
2
5
8
4,
0
3
.
0
4
3
2
0
2
1
2
2
5
3
2
0
1
Recovery Measures
Extent of
Current Use
., - Effectiveness
Increase
Readability
On-Site
Recycling
Off-site
Recycling
Waste
1 . Maintain minimum 5
solvent in waste.
2. Segregation 6
of the wastes.
1 . Reconsider 9
on-site distillation unit.
2. Reuse of 7
cleaning solvent.
3. Rework of
cleanup solvent. 6
4. Rework wastes. 6
5. Reuse filter bags. 5
1 . Off-she reclamation 7
/incineration.
1. Off-site reuse. 3
5
4
0
3
4
4
5
"7
0
Future
Application
Potential
5
6
9
7
7
7
5
4
3
Current
Reduction
Index
3
2
0
2
2
2
3
5
0
0
«
. 1
3'
-
1
. •
0
3
1
2.
2,
2
1
2
2
3
4
1
2
for Plant B.
Future
Reduction
Index
1
2
8
3
3
3
1
1
1
Exchange
59
-------
options, such as reuse of cleaning solvent and rework of
various waste streams, are to be examined by Plant B for
their technical feasibility. Since these measures involve
more efficient use of the materials, the economic benefits
are obvious.
On-site Distillation
On-site distillation was attempted in the past at Plant B and
was discontinued as it proved unprofitable.. But present
disposal costs and their expected increases justify a re-
examination of this option. The following conditions must
be satisfied for the distillation still to be purchased and
installed:
• Thestillshouldmeetthetechnicalrequirements
for reclaiming the solvents;
• The economics of on-site distillation must be
proven to be favorable; and
• The measure should be proven to be an
environmentally safer option (short term and
longtenn) compared to thepresentlyemployed
off-site recycling.
The total wastesentto the off-siterecyclerin 1985is223.5
tons/yr, which amounts to 44,700 gal/yr (assuming a
density of 10 Ib/gal). Assuming a one shift operation and
aSday work week,amaximum of 2,080 hrs/yr of onstream
time is available. This results in a minimum throughput of
21.5 gal/hr. Using a conservative estimate of 5 hours per
batch.abatch capacity of 100 gallons isrecommended. For
a base case analysis, the economics of using the Progres-
siveRecoverylnc. (PRI)ModelSC-400,whichhasabatch
capacity of 120 gallons, is presented in Table A-ll.
Based on the analysis presented in Table A-l 1 the instal-
lation of anon-sitestillappearstobeeconomicaUyattrac:tive
since it has a payback period of 1.9 years, and, as such, is
much less than the (rule-of-the-thumb) hurdle rate of 3
years. As this economic analysis does not consider the
major price hikes contemplated by therecycler, the on-site
distillation option has an even greater economic appeal.
The technical feasibility of on-site distillation can be
examined by sending a solvent waste sample to PRI. The
reclaimed solvent and the distillation residues returned by
PRI can be examined by Plant B for the distillate yield and
the quality of recovered solvent. PRI's equipment has been
used to handle paint process wastes at other facilities and
is therefore expected to meet the requirements of Plant B.
On-site reclamation has the following benefits:
• The transportation of the wastes and the
associated risks are minimized because less
waste leaves the facility;
• Plant B has more control over the purity of the
reclaimed solvent;
• Even though the distillation residues require
off-site incineration, the disposal costs will be
less affected by increases in charges by off-site
recyclers, because the waste volume is
considerably reduced;
• It is cheaper to recover on-site; and
• On-sitereclamationisnotconsideredtreatment
by RCRA and therefore does not require a
TSDF status to be obtained by the facility.
Table A-ll. Economics of On-Site
Distillation
Installation Costs
Capital cost, still, PRI Modal SC-400 with $ 32,150
autofill and cycle complete shutoff
Freight Cost (a) 1.930
Tax (b) 2,090
installation (labor plus supplies), 50 ft. 3,500
of 1* pipe for cooling water and two
explosion-proof conduits
Total Installed Cost $39.670
Current Annual Disposal Costs
Recycling costs @ $130Aon
Surcharge for disposal of distillation
residues @ $150Aon
Total Disposal Costs
Annual Incremental Savings
Lost raw material costs (c)
Disposal costs (d)
Labor (e)
Other (utilities) (f)
Savings
Pay back period, years
(a) Estimated as 6 % of capital cost
(b) 6.5% sales tax
(c) The solvent is assumed to bo MEK.
(d) Incineration of distillation residues @ $200/ton
assumed, and a 90 % solvent recovery
process. The disposal cost of
distillation residues is $ 17,970.
(e)Estimated for 40 hr/wk @ $9.00/hr.
(f)Based on a still operating cost of $0.30/gal of
recovered solvent.
The disadvantages of on-site reclamation are:
• Capital investment needed for the still
• Additional operating costs
• Possible need for operator training
• Air quality permits may be needed to operate
the equipment
29,055
33.525
$ 62,580
6,980
44,610
-18.720
-12.023
$20,847
1.9
60
-------
• Landfill disposal optionfor distillation bottoms
is probably not available, as it is doubtful that
residues will pass the new TCLP test
requirements (Nov. 8, 1986 landfill ban
regulations). This leaves only the incineration
option.
• Liability and risks due to improper equipment
operation or solvent quality maintenance are
incurred.
Because distillation bottoms can be incinerated off-site,
environmental and regulatory concern do not play as big a
role in the decision to convert to on-site reclamation as do
economics.
Caustic Sludge Dewatering
Alkaline cleaning of portable tanks produces a sludge that
is sent to the off-site recycler for incineration. This sludge
contains a significant amount of alkaline solution. De-
watering will decrease the sludge volume, reducing dis-
posal costs. At present, 132. tons/yr of sludge is disposed
of at a cost of $1.00/gal through an off-site recycler.
Assuming the density of 10 Ib/gal for the sludge, this
represents an annual disposal cost of $ 2,640. Assuming
that the sludge contains 10 percent of solids, and that
dewatering produces sludge with 30% solids, a savings of
$ 1,770/yr can be achieved. The operating costs of a
dewatering unit were not subtracted from these savings.
Small savings such as these do not seem to warrant the
purchase of even a not-very-efficient filtration unit In
addition, the environmental benefits of dewatering are
questionable. The recovered aqueous portion will need
additional treatment such as neutralization before dis-
charge to the sewer. Therefore, caustic sludge dewatering
is not expected to have any significant economic or
environmental impact
Replacement of Caustic Cleaning Solution
The presently used caustic cleaning solution could be
replaced with more efficient commercially available alka-
line cleaning agents. Based on the experience of a different
facility, a SO percent reduction in cleaning solution re-
placement is expected. This translates roughly into a
reduction of SO percent in sludge waste volume, or a
savings of about $ 1320/yr. The increase in the purchase
cost of the cleaning solution should be lower than this
amount to justify substitution. In addition, the effective-
ness of the new cleaning solution would need to be demon-
strated on a trial basis.
Avoidance of Unnecessary Cleaning
The technical feasibility of eliminating a cleanup step can
be established by examining its effect on product quality in
a lab scale experiment. If product contamination is within
quality control standards of the facility, the cleanup step
can be eliminated. This option does not involve any capital
investment If avoiding unnecessary cleaning can result in
a decrease of 10 percent in waste volume, about $6,0007
yr in present disposal costs would be saved.
Replace Cartridges with Bag Filters
Plant B uses cartridges in two filtration units, each con-
taining six cartridges. To use bag filters in place of
cartridges, one possibility is the purchase of 12 new filter
housings. Other possibilities include the purchase of two
housings, each containing sue bag filters. As an example,
Table A-12 presents die economics of replacing cartridge
filters with bag filters in 12 new housings. The payback
period is 7.4 years and therefore the option is not
considered viable. The use of two filter housings, each
holding six filters (with total capital cost of $ 20,000) does
not seem to significantly reduce the payback period. In
addition, the technical feasibility of using bag filters in
place of cartridges must be eiitablished through trial runs.
Table A-12. Economics of Replacing Cartridge
Filters with Bag Filter:;
Instaltod Cost
Fitter housings (12), delivered cost
including tax and freight
Installation including labor
and supplies
Total Installed Cost
Annual Incremental Savings
Raw materials, solvents (a)
Disposal costs (b)
Operating costs (c)
Savings
Payback period, years
$ 20,950
3,000
$23,950
470
2,770
0
$ 3,240
7.4
(a)Assuming no solvent retention in bag filters.
(b)tt is assumed that the cartridge filters are
replaced 12 times/week. Using bag fitters in
their place reduces volume of solid waste by
6.0 fl3/wk. Current disposal fee is assumed to
be $9.25/ft3.
(c)The bags are replaced 3 times/wk at $12/bag
and the cartridges are replaced 12 times/wk
at $3/cartridge.bag filters in place of cartridges
must be established through trial runs.
Replace Cartridges and Bag Filters with Wire Mesh
Filters
Plant B uses four bag filter units and 12 cartridge filter
units. The wire screen filters can be reused almost indefi-
nitely because they are backwashable. Therefore, this
measure could eliminate the spent filter bag/cartridge
61
-------
waste. Table A-13 presents fee economics of replacing
these with wire mesh screens. The increase in disposal
costsassociated with thesolvent-bearingwaste from back-
washingis not consitoed to be significantin this analysis.
Such a waste can be combined with other solvent wastes
destined for reclamation. As seen from Table A-13 the
paybackperiodforimplementingfeis measureis0.2years.
Plant B is already testing the effectiveness of some wire
mesh filters. If the-technical requirements are met, it is
recommended that wire mesh filters replace bag/cartridge
filters.
Table A-13. Economic Aspects of Replacing
Bag or Cartridge
FILTERS WITH "WERE MESH FILTERS
Installed Cost*
Mata! mash filters (16), delivered
cost including sales tax
Installation, including labor and
supplies
Total Installed Costs
Annual Incremental Savings
Raw material, solvents (a)
Disposal costs (b)
Labor (c)
Other (cartridges.bags) (d)
Total Savings
Payback Period, years
$ 2,550
4,000
$ 6,550
470
2,775
0
$ 28,800
$32,045
0.2
(a)Based on 1 ton/yr toss of solvent (MEK)
(b)Basad on reducing the volume of solidified
waste by 6.0 ftSAvk. Current disposal fee is
$9.25/ft3.
(c)Assuming that the change in labor costs is
riot significant
(d)Based on the use of 144 cartridges/wk at
$3.00/cartridge and 12 bags/wk at $12.00/
bag.
Summary and Discussion
PlantB's majorsource of waste generation is the equipment
cleaning operation. A number of waste minimization
options toreduce,reuse, orrecycleeach of fee wastes was
identified. After rating fee options, the following were
chosen for additional economic analysis:
• on-site distillation
• caustic sludge dewatering
• replacement of caustic cleaning solution
• avoidance of unnecessary cleaning
. V
• replacement of cartridges wife bag filters
• replacement of cartridges and uags wife wire
screen filters
The equipment cleaning wastes can be distilled on-site at
an annual savings of about $21,000. The payback period
for installation of an automatic still is 1.9 years, which
makesfeisoptioneconomicallyattractive. Ofeermeasures
considered to have good potential are avoidance of un-
necessary cleaning and replacement of caustic cleaning
solution.
Caustic sludge dewatering, though effective in decreasing
waste volume, is not recommended because fee environ-
mental and economic benefits do not seem significant
enough to warrant capital investment. Replacement of
cartridges wife bagfiltershasapaybackperiod of about7.4
years and is therefore not a viable option. However,
replacement of bags or cartridges wife wire screen filters
has a payback period of 0.2 years and therefore is highly
attractive if fee technical requirements are met
On-site distillation appears to be economically feasible
and tooffersignificantwaste reduction potential; however,
its technical feasibility needs to be established. Also, fee
technical feasibility of using wire screen filters in place of
bag or cartridge filters needs to be established.
62
-------
APPENDIX B
WHERE TO GET HELP
FURTHER INFORMATION ON POLLUTION PREVENTION
Additional information on soorcereductioE, reuse and
recycling approaches to pollution prevention is available
inEPAreports listed in this section, and through state pro-
grams (listed below) that offer technical and/or financial
assistance in the areas of pollution prevention and treat-
ment
In addition, waste exchanges have been established in
some areas of the U.S. to put waste generators in contact
with potential usersof the waste. Four waste exchanges are
listed below. Finally, EPA's regional offices ate listed.
EPA REPORTS ON WASTE MINIMIZATION
U.S. Environmental Protection Agency. "Waste
Minimization AiiditReporcCaseStudiesof Corrosive
and Heavy Metal Waste Minimization Audit at a
Specialty Steel Manufacturing Complex." Executive
Summary.*
U.S. Environmental Protection Agency. "Waste
Minimization Audit Report: Case Studies of
Minimization of SolventWasteforPartsCleaningand
from Electronic Capacitor ManufacturingOperation."
Executive Summary.*
U.S. Environmental Protection Agency. "Waste
Minimization Audit Report: Case Studies of
Minimization of Cyanide Wastes from Electroplating
Operations." Executive Summary.*
U.S. Environmental Protection Agency. Report to
Congress: Waste Minimization, Vols. I and II. EPA/
530-SW-86-033 and -034 (Washington, D.C.: U.S.
EPA, 1986).**
U.S. Environmental Protection Agency. Waste
Minimization - Issues and Options, Vols. I-III EPA/
530-SW-86-041 through -043. (Washington, D.C.:
U.S. EPA, 1986).**
* Executive Summary available from EPA,
WMDDRD, RREL, 26 West Martin Luther King Drive,
Cincinnati, OH, 45268; full report available from the
National Technical Information Service (NTIS), U.S.
Department of Commerce, Springfield, VA 22161.
** Available from the National Technical Information
Service as a five-volume set, NTIS No. PB-87-114-328.
WASTE REDUCTION TECHNICAL/FINANCIAL
ASSISTANCE PROGRAM!?
The EPA'sOffice of Solid Waste andEmergency Re-
sponse has set up a telephone call-in service to answer
questions regarding RCRA and Superfund (CERCLA):
(800) 242-9346 (outside the District of Columbia)
(202)382-3000 (in the District of Columbia)
The following states have programs mat offer technical
and/or financial assistance in the areas of waste minimiza-
tion and treatment
Alabama
Hazardous Material Management and Resources Recov-
ery Program
University of Alabama
P.O. Box 6373
Tuscaloosa, AL 35487-6373
(205) 348-8401
Alaska
Alaska Health Project
Waste Reduction Assistance Program
431 West Seventh Avenue, Suite 101
Anchorage, AK 99501
(907) 276-2864
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 Service
714/744 P Street
Sacramento, CA 94234-7320
(916) 324-1807
Connecticut ;
Connecticut Hazardous Waste Management Service
Suite 360
900 Asylum Avenue
Hartford, CT 06105
(203) 244-2007
63
-------
Connecticut Department of Economic Development
210 Washington Street
Hartford, CT 06106
(203) 566-7196
Georgia
Hazardous Waste Technical Assistance Program
Georgia Institute of Technology
Georgia Technical Research Institute
Environmental-Health and Safety-Division
Of Keefe Building, Room 027
Atlanta, GA 30332
(404) 894-3806
Environmental Protection Division
Georgia Department of Natural Resources
Floyd Towers East, Suite 1154
205 Butler Street
Atlanta, GA 30334
(404) 656-2833
Illinois
Hazardous Waste Research and Information Center
Illinois Department of Energy of Energy and Natural
Resources
1808 Woodfield Drive
Savoy, IL 61874
(217) 333-8940
Illinois Waste Elimination Research Center
Pritzker Department of Environmental Engineering
Alumni Building, Room 102
Illinois Institute of Technology
3200 South Federal Street
Chicago, IL 60616
(313) 567-3535
Indiana
Environmental Management and Education Program
Young Graduate House, Room 120
Purdue University
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
205 Engineering Annex
Iowa State University
Ames, IA 50011
(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
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
ISReiUyRoad
Frankfort, KY 40601
(502) 564-6716
Louisiana
Department of Environmental Quality
Office of Solid and Hazardous Waste
P.O. Box 44307
Baton Rouge, LA 70804
(504) 342-1354
Maryland
Maryland Hazardous Waste Facilities Siting Board
60 West Street, Suite 200 A
Annapolis, MD 21401
(301) 974-3432
Maryland Environmental Service
2020 Industrial Drive
Annapolis, MD 21401
(301) 269-3291
(800) 492-9188 (in Maryland)
Massachusetts
Office of Safe Waste Management
Department of Environmental Management
100 Cambridge Street, Room 1094
Boston, MA 02202
(617) 727-3260
Source Reduction Program
Massachusetts Department of Environmental Quality En-
gineering
1 Winter Street
Boston, MA 02108
(617) 292-5982
64
-------
Michigan
Resource Recovery Section
Department of Natural Resources
P.O.Box30028
Lansing, MI 48909 J
(517) 373-0540
Minnesota
Minnesota Pollution Control Agency
Solid and Hazardous Waste Division
520 Lafayette Road
SL Paul, MN 55155
(612)296-6300
Minnesota Technical Assistance Program
W-140 Boynton Health Service
University of Minnesota
Minneapolis, MN 55455
(612)625-9677
(800) 247-0015 (in Minnesota)
Minnesota Waste Management Board
123 Thorson Center
7323 Fifty-Eighth Avenue North
Crystal, MN 55428
(612)536-0816
Missouri
State Environmental Improvement and Energy
Resources Agency
P.O. Box 744
Jefferson City, MO 65102
(314) 751-4919
New Jersey
New Jersey Hazardous Waste Facilities Siting
Commission
Room 614
28 West State Street
Trenton, NJ 08608
(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
Risk Reduction Unit
Office of Science and Research
New Jersey Department of Environmental Protection
401 East State Street
Trenton, NJ 08625
New York
New York State Environmental Facilities
Corporation
50 Wolf Road
Albany, NY 12205
(518)457-3273
North Carolina
Pollution Prevention Pays Program
Department of Natural Resources and
Community Development
P.O. Box 27687
512 Norm Salisbury Street
Raleigh, NC 27611
(919)733-7015
Governor's Waste Management Board
325 Norm Salisbury Street
Raleigh, NC 27611
(919) 733-9020
Technics! Assistance Unit
Solid and Hazardous Waste Management Branch
North Carolina Department of Human Resources
P.O. Box 2091
306 North Wilmington Street
Releigh,NC 27602
(919)733-2178
Ohio
Division of Solid and Hazardous Waste Management
Ohio Environmental Protection Agency
P.O. Box 1049
1800 WaterMark Drive
Columbus, OH 43266-1049
(614)481-7200
Ohio Technology Transfer Organization
Suite 200
65 East State Street
Columbus, OH 43266-0330
(614)466-4286
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
65
-------
Pennsylvania
Pennsylvania Technical Assistance Program
501F. Orvis Keller Building
University Park, PA 16802
(814)865-0427
Center of Hazardous Material Research
320 William Pitt Way
Pittsburgh, PA 15238
(412)826-5320
Bureau of Waste Management
Pennsylvania Department of
Environmental Resources
P.O. Box 2063
Fulton Building
3rd and Locust Streets
Harrisburg, PA 17120
(717) 787-6239
Rhode Island
Ocean State Cleanup and Recycling Program
Rhode Island Department of Environmental Management
9 Hayes Street
Providence, RI02908-5003
(401)277-3434
(800) 253-2674 (in Rhode Island)
Center for Environmental Studies
Brown University
P.O. Box 1943
135 Angell Street
Providence, RI 02912
(401) 863-3449
Tennessee
Center for Industrial Services
102 Alumni Hall
University of Tennessee
Knoxvffle,TN 37996
(615) 974-2456
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
01ympia,WA 98504-8711
(206)459-6322
Wisconsin
Bureau of Solid Waste Management
Wisconsin Department of Natural Resources
P.O. Box 7921
101 South Webster Street
Madison, WI53707
(608)267-3763
Wyoming
Solid Waste Management Program
Wyoming Department of Environmental Quality
Herchler Building, 4th Floor, West Wing
122 West 25th Street
Cheyenne, WY 82002
(307)777-7752 V
WASTE EXCHANGES
Northeast Industrial Exchange
90 Presidential Plaza, Syracuse, NY 13202
(315)422-6572
Southern Waste Information Exchange
P.O. Box 6487, Tallahassee, FL 32313
(904) 644-5516
California Waste Exchange
Department of Health Services
Toxic Substances Control Division
Alternative Technology & Policy Development Sectioi
714 P Street
Sacramento, CA 95814
(916) 324-1807
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)
26 Federal Plaza
New York, NY 10278
(212) 264-2525
Region 3 (PA, DE, MD, WV, VA)
841 Chestnut Street
Philadelphia, PA 19107
(215) 597-9800
Region 4 (KY, TN, NC, SC, GA, FL, AL, MS)
345 Courtland Street, NE
Atlanta, GA 30365
66
-------
(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, ffi)
215 Fremont Street
San Francisco, CA 94105
(415)974-8071
Region 10 (AK, WA, OR, ID)
1200 Sixth Avenue
Seattle, WA 98101
(206)442-5810
• U.S. Covernnent Prtntine Officf• 1990-74B-!59/00482
67
-------
-------
-------
------- |